Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry.

PubMed

Sundararaman, Ravishankar; Goddard, William A; Arias, Tomas A

2017-03-21

First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition. We present two distinct algorithms: a self-consistent field method and a direct variational free energy minimization method using auxiliary Hamiltonians (GC-AuxH), to solve the Kohn-Sham equations of electronic density-functional theory directly in the grand canonical ensemble at fixed potential. Both methods substantially improve performance compared to a sequence of conventional fixed-number calculations targeting the desired potential, with the GC-AuxH method additionally exhibiting reliable and smooth exponential convergence of the grand free energy. Finally, we apply grand-canonical density-functional theory to the under-potential deposition of copper on platinum from chloride-containing electrolytes and show that chloride desorption, not partial copper monolayer formation, is responsible for the second voltammetric peak.

Grand canonical electronic density-functional theory: Algorithms and applications to electrochemistry

DOE PAGES

Sundararaman, Ravishankar; Goddard, III, William A.; Arias, Tomas A.

2017-03-16

First-principles calculations combining density-functional theory and continuum solvation models enable realistic theoretical modeling and design of electrochemical systems. When a reaction proceeds in such systems, the number of electrons in the portion of the system treated quantum mechanically changes continuously, with a balancing charge appearing in the continuum electrolyte. A grand-canonical ensemble of electrons at a chemical potential set by the electrode potential is therefore the ideal description of such systems that directly mimics the experimental condition. We present two distinct algorithms: a self-consistent field method and a direct variational free energy minimization method using auxiliary Hamiltonians (GC-AuxH), to solvemore » the Kohn-Sham equations of electronic density-functional theory directly in the grand canonical ensemble at fixed potential. Both methods substantially improve performance compared to a sequence of conventional fixed-number calculations targeting the desired potential, with the GC-AuxH method additionally exhibiting reliable and smooth exponential convergence of the grand free energy. Lastly, we apply grand-canonical density-functional theory to the under-potential deposition of copper on platinum from chloride-containing electrolytes and show that chloride desorption, not partial copper monolayer formation, is responsible for the second voltammetric peak.« less

Potential Energy Surface of the Chromium Dimer Re-re-revisited with Multiconfigurational Perturbation Theory.

PubMed

Vancoillie, Steven; Malmqvist, Per Åke; Veryazov, Valera

2016-04-12

The chromium dimer has long been a benchmark molecule to evaluate the performance of different computational methods ranging from density functional theory to wave function methods. Among the latter, multiconfigurational perturbation theory was shown to be able to reproduce the potential energy surface of the chromium dimer accurately. However, for modest active space sizes, it was later shown that different definitions of the zeroth-order Hamiltonian have a large impact on the results. In this work, we revisit the system for the third time with multiconfigurational perturbation theory, now in order to increase the active space of the reference wave function. This reduces the impact of the choice of zeroth-order Hamiltonian and improves the shape of the potential energy surface significantly. We conclude by comparing our results of the dissocation energy and vibrational spectrum to those obtained from several highly accurate multiconfigurational methods and experiment. For a meaningful comparison, we used the extrapolation to the complete basis set for all methods involved.

Layered synthetic microstructures as Bragg diffractors for X rays and extreme ultraviolet - Theory and predicted performance

NASA Technical Reports Server (NTRS)

Underwood, J. H.; Barbee, T. W., Jr.

1981-01-01

The theory of X-ray diffraction by periodic structures is applied to the layered synthetic microstructures (LSMs) made possible by recent developments in thin film technology, and approximate formulas for estimating their performance are presented. A more complete computation scheme based on optical multilayer theory is also described, and it is shown that the diffracting properties may be tailored to specific applications by adjusting the refractive indices and thicknesses of the component layers. The theory may be modified to take account of imperfections in the LMS structure, and the properties of nonperiodic structures thereby computed. Structures with high integrated reflectivity constructed according to the methods defined have potential application in many areas of X-ray or EUV research and instrumentation.

Strong-field ionization of Li and Be: a time-dependent density functional theory with self-interaction correction

NASA Astrophysics Data System (ADS)

Telnov, Dmitry A.; Heslar, John T.; Chu, Shih-I.

2011-11-01

In the framework of the time-dependent density functional theory, we have performed 3D calculations of multiphoton ionization of Li and Be atoms by strong near-infrared laser fields. The results for the intensity-dependent probabilities of single and double ionization are presented. We make use of the time-dependent Krieger-Li-Iafrate exchange-correlation potential with self-interaction correction (TD-KLI-SIC). Such a potential possesses an integer discontinuity which improves description of the ionization process. However, we have found that the discontinuity of the TD-KLI-SIC potential is not sufficient to reproduce characteristic feature of double ionization.

What Is Improvement Science? Do We Need It in Education?

ERIC Educational Resources Information Center

Lewis, Catherine

2015-01-01

The theory and tools of "improvement science" have produced performance improvements in many organizational sectors. This essay describes improvement science and explores its potential and challenges within education. Potential contributions include attention to the knowledge-building and motivational systems within schools, strategies…

Five-dimensional fermionic Chern-Simons theory

NASA Astrophysics Data System (ADS)

Bak, Dongsu; Gustavsson, Andreas

2018-02-01

We study 5d fermionic CS theory with a fermionic 2-form gauge potential. This theory can be obtained from 5d maximally supersymmetric YM theory by performing the maximal topological twist. We put the theory on a five-manifold and compute the partition function. We find that it is a topological quantity, which involves the Ray-Singer torsion of the five-manifold. For abelian gauge group we consider the uplift to the 6d theory and find a mismatch between the 5d partition function and the 6d index, due to the nontrivial dimensional reduction of a selfdual two-form gauge field on a circle. We also discuss an application of the 5d theory to generalized knots made of 2d sheets embedded in 5d.

Optimum performance and potential flow field of hovering rotors

NASA Technical Reports Server (NTRS)

Wu, J. C.; Sigman, R. K.

1975-01-01

Rotor and propeller performance and induced potential flowfields were studied on the basis of a rotating actuator disk concept, with special emphasis on rotors hovering out of ground effect. A new theory for the optimum performance of rotors hovering OGE is developed and presented. An extended theory for the optimum performance of rotors and propellers in axial motion is also presented. Numerical results are presented for the optimum distributions of blade-bound circulation together with axial inflow and ultimate wake velocities for the hovering rotor over the range of thrust coefficient of interest in rotorcraft applications. Shapes of the stream tubes and of the velocities in the slipstream are obtained, using available methods, for optimum and off-optimum circulation distributions for rotors hovering in and out of ground effect. A number of explicit formulae useful in computing rotor and propeller induced flows are presented for stream functions and velocities due to distributions of circular vortices over axi-symmetric surfaces.

Autobiographical Memory in Adults with Autism Spectrum Disorder: The role of Depressed Mood, Rumination, Working Memory and Theory of Mind

ERIC Educational Resources Information Center

Crane, Laura; Goddard, Lorna; Pring, Linda

2013-01-01

Autobiographical memory difficulties have been widely reported in adults with autism spectrum disorder (ASD). The aim of the current study was to explore the potential correlates of autobiographical memory performance (including depressed mood, rumination, working memory and theory of mind) in adults with ASD, relative to a group of typical adults…

Phase structure of completely asymptotically free SU(Nc) models with quarks and scalar quarks

NASA Astrophysics Data System (ADS)

Hansen, F. F.; Janowski, T.; Langæble, K.; Mann, R. B.; Sannino, F.; Steele, T. G.; Wang, Z. W.

2018-03-01

We determine the phase diagram of completely asymptotically free SU (Nc) gauge theories featuring Ns complex scalars and Nf Dirac quarks transforming according to the fundamental representation of the gauge group. The analysis is performed at the maximum known order in perturbation theory. We unveil a very rich dynamics and associated phase structure. Intriguingly, we discover that the completely asymptotically free conditions guarantee that the infrared dynamics displays long-distance conformality, and in a regime when perturbation theory is applicable. We conclude our analysis by determining the quantum corrected potential of the model and summarizing the possible patterns of radiative symmetry breaking. These models are of potential phenomenological interest as either elementary or composite ultraviolet finite extensions of the standard model.

Density functional theory (DFT) study of a new novel bionanosensor hybrid; tryptophan/Pd doped single walled carbon nanotube

NASA Astrophysics Data System (ADS)

Yoosefian, Mehdi; Etminan, Nazanin

2016-07-01

In order to explore a new novel L-amino acid/transition metal doped single walled carbon nanotube based biosensor, density functional theory calculations were studied. These hybrid structures of organic-inorganic nanobiosensors are able to detect the smallest amino acid building block of proteins. The configurations of amine and carbonyl group coordination of tryptophan aromatic amino acid adsorbed on Pd/doped single walled carbon nanotube were compared. The frontier molecular orbital theory, quantum theory atom in molecule and natural bond orbital analysis were performed. The molecular electrostatic potential and the electron density surfaces were constructed. The calculations indicated that the Pd/SWCNT was sensitive to tryptophan suggesting the importance of interaction with biological molecule and potential detecting application. The proposed nanobiosensor represents a highly sensitive detection of protein at ultra-low concentration in diagnosis applications.

Potential Theory for Directed Networks

PubMed Central

Zhang, Qian-Ming; Lü, Linyuan; Wang, Wen-Qiang; Zhou, Tao

2013-01-01

Uncovering factors underlying the network formation is a long-standing challenge for data mining and network analysis. In particular, the microscopic organizing principles of directed networks are less understood than those of undirected networks. This article proposes a hypothesis named potential theory, which assumes that every directed link corresponds to a decrease of a unit potential and subgraphs with definable potential values for all nodes are preferred. Combining the potential theory with the clustering and homophily mechanisms, it is deduced that the Bi-fan structure consisting of 4 nodes and 4 directed links is the most favored local structure in directed networks. Our hypothesis receives strongly positive supports from extensive experiments on 15 directed networks drawn from disparate fields, as indicated by the most accurate and robust performance of Bi-fan predictor within the link prediction framework. In summary, our main contribution is twofold: (i) We propose a new mechanism for the local organization of directed networks; (ii) We design the corresponding link prediction algorithm, which can not only testify our hypothesis, but also find out direct applications in missing link prediction and friendship recommendation. PMID:23408979

Gravitational potential as a source of earthquake energy

USGS Publications Warehouse

Barrows, L.; Langer, C.J.

1981-01-01

Some degree of tectonic stress within the earth originates from gravity acting upon density structures. The work performed by this "gravitational tectonics stress" must have formerly existed as gravitational potential energy contained in the stress-causing density structure. According to the elastic rebound theory (Reid, 1910), the energy of earthquakes comes from an elastic strain field built up by fairly continuous elastic deformation in the period between events. For earthquakes resulting from gravitational tectonic stress, the elastic rebound theory requires the transfer of energy from the gravitational potential of the density structures into an elastic strain field prior to the event. An alternate theory involves partial gravitational collapse of the stress-causing density structures. The earthquake energy comes directly from a net decrease in gravitational potential energy. The gravitational potential energy released at the time of the earthquake is split between the energy released by the earthquake, including work done in the fault zone and an increase in stored elastic strain energy. The stress associated with this elastic strain field should oppose further fault slip. ?? 1981.

Massively parallel GPU-accelerated minimization of classical density functional theory

NASA Astrophysics Data System (ADS)

Stopper, Daniel; Roth, Roland

2017-08-01

In this paper, we discuss the ability to numerically minimize the grand potential of hard disks in two-dimensional and of hard spheres in three-dimensional space within the framework of classical density functional and fundamental measure theory on modern graphics cards. Our main finding is that a massively parallel minimization leads to an enormous performance gain in comparison to standard sequential minimization schemes. Furthermore, the results indicate that in complex multi-dimensional situations, a heavy parallel minimization of the grand potential seems to be mandatory in order to reach a reasonable balance between accuracy and computational cost.

Lenard-Balescu calculations and classical molecular dynamics simulations of electrical and thermal conductivities of hydrogen plasmas

DOE PAGES

Whitley, Heather D.; Scullard, Christian R.; Benedict, Lorin X.; ...

2014-12-04

Here, we present a discussion of kinetic theory treatments of linear electrical and thermal transport in hydrogen plasmas, for a regime of interest to inertial confinement fusion applications. In order to assess the accuracy of one of the more involved of these approaches, classical Lenard-Balescu theory, we perform classical molecular dynamics simulations of hydrogen plasmas using 2-body quantum statistical potentials and compute both electrical and thermal conductivity from out particle trajectories using the Kubo approach. Our classical Lenard-Balescu results employing the identical statistical potentials agree well with the simulations.

Maternal history of depression is associated with enhanced theory of mind in depressed and nondepressed adult women.

PubMed

Harkness, Kate Leslie; Washburn, Dustin; Theriault, Jordan Eugene; Lee, Lisa; Sabbagh, Mark Alan

2011-08-30

Theory of mind forms the basis of social cognition and develops on a stereotyped ontogenetic timetable. Yet, there are individual differences in theory of mind that may be transmitted through genetic and/or environmental mechanisms. In the current study we examined the relation of maternal history of depression to individual differences in theory of mind in a sample of adult women. Sixty-one depressed women (23% with a positive maternal history of depression) and 30 non-depressed women (33% with a positive maternal history of depression) completed the 'Reading the Mind in the Eyes task', a test of theory of mind decoding. Women with a maternal history of depression performed better on the Eyes task than those without. Further, the younger the mother's onset of depression, the better the current probands' Eyes task performance. These results are consistent with a broader literature linking hypersensitive social cognition and depression risk. We discuss the potential clinical implications of our results. Copyright © 2011 Elsevier Ltd. All rights reserved.

Our Students Suffer from Both Lack of Knowledge and Consistency: A PPT (Potential Performance Theory) Analysis of Test-Taking

ERIC Educational Resources Information Center

Rice, Stephen; Geels, Kasha; Trafimow, David; Hackett, Holly

2011-01-01

Test scores are used to assess one's general knowledge of a specific area. Although strategies to improve test performance have been previously identified, the consistency with which one uses these strategies has not been analyzed in such a way that allows assessment of how much consistency affects overall performance. Participants completed one…

Instructional Approach to Molecular Electronic Structure Theory

ERIC Educational Resources Information Center

Dykstra, Clifford E.; Schaefer, Henry F.

1977-01-01

Describes a graduate quantum mechanics projects in which students write a computer program that performs ab initio calculations on the electronic structure of a simple molecule. Theoretical potential energy curves are produced. (MLH)

The fourth dimension: A motoric perspective on the anxiety-performance relationship.

PubMed

Carson, Howie J; Collins, Dave

2016-01-01

This article focuses on raising concern that anxiety-performance relationship theory has insufficiently catered for motoric issues during, primarily, closed and self-paced skill execution (e.g., long jump and javelin throw). Following a review of current theory, we address the under-consideration of motoric issues by extending the three-dimensional model put forward by Cheng, Hardy, and Markland (2009) ('Toward a three-dimensional conceptualization of performance anxiety: Rationale and initial measurement development, Psychology of Sport and Exercise , 10 , 271-278). This fourth dimension, termed skill establishment , comprises the level and consistency of movement automaticity together with a performer's confidence in this specific process, as providing a degree of robustness against negative anxiety effects. To exemplify this motoric influence, we then offer insight regarding current theories' misrepresentation that a self-focus of attention toward an already well-learned skill always leads to a negative performance effect. In doing so, we draw upon applied literature to distinguish between positive and negative self-foci and suggest that on what and how a performer directs their attention is crucial to the interaction with skill establishment and, therefore, performance. Finally, implications for skill acquisition research are provided. Accordingly, we suggest a positive potential flow from applied/translational to fundamental/theory-generating research in sport which can serve to freshen and usefully redirect investigation into this long-considered but still insufficiently understood concept.

Coupling-parameter expansion in thermodynamic perturbation theory.

PubMed

Ramana, A Sai Venkata; Menon, S V G

2013-02-01

An approach to the coupling-parameter expansion in the liquid state theory of simple fluids is presented by combining the ideas of thermodynamic perturbation theory and integral equation theories. This hybrid scheme avoids the problems of the latter in the two phase region. A method to compute the perturbation series to any arbitrary order is developed and applied to square well fluids. Apart from the Helmholtz free energy, the method also gives the radial distribution function and the direct correlation function of the perturbed system. The theory is applied for square well fluids of variable ranges and compared with simulation data. While the convergence of perturbation series and the overall performance of the theory is good, improvements are needed for potentials with shorter ranges. Possible directions for further developments in the coupling-parameter expansion are indicated.

Improved Academic Performance and Enhanced Employability? The Potential Double Benefit of Proactivity for Business Graduates

ERIC Educational Resources Information Center

Tymon, Alex; Batistic, Sasa

2016-01-01

This study contributes to proactivity theory and debate on how universities meet competing stakeholder demands in an increasingly marketized higher education environment. We explore how the interplay between the stable facet of proactive personality and the situated behaviour of personal initiative influence academic performance. We hypothesized…

Linking Rubrics and Academic Performance: An Engagement Theory Perspective

ERIC Educational Resources Information Center

Francis, Julie Elizabeth

2018-01-01

While marking rubrics offer a range of potential benefits for students and staff, educators are working to develop a richer understanding of the most effective ways to unlock these benefits. This study contributes by examining the link between rubrics and performance through the lens of student engagement. The work introduced an assessment rubric…

Letting the Drama into Group Work: Using Conflict Constructively in Performing Arts Group Practice

ERIC Educational Resources Information Center

Crossley, Tracy

2006-01-01

The article examines conflict avoidance in performing arts group work and issues arising in relation to teaching and learning. In group theory, conflict is addressed largely in terms of its detrimental effects on group work, and its constructive potential is often marginalized. Similarly, undergraduate students usually interpret "effective…

Combining Theory-Driven Evaluation and Causal Loop Diagramming for Opening the 'Black Box' of an Intervention in the Health Sector: A Case of Performance-Based Financing in Western Uganda.

PubMed

Renmans, Dimitri; Holvoet, Nathalie; Criel, Bart

2017-09-03

Increased attention on "complexity" in health systems evaluation has resulted in many different methodological responses. Theory-driven evaluations and systems thinking are two such responses that aim for better understanding of the mechanisms underlying given outcomes. Here, we studied the implementation of a performance-based financing intervention by the Belgian Technical Cooperation in Western Uganda to illustrate a methodological strategy of combining these two approaches. We utilized a systems dynamics tool called causal loop diagramming (CLD) to generate hypotheses feeding into a theory-driven evaluation. Semi-structured interviews were conducted with 30 health workers from two districts (Kasese and Kyenjojo) and with 16 key informants. After CLD, we identified three relevant hypotheses: "success to the successful", "growth and underinvestment", and "supervision conundrum". The first hypothesis leads to increasing improvements in performance, as better performance leads to more incentives, which in turn leads to better performance. The latter two hypotheses point to potential bottlenecks. Thus, the proposed methodological strategy was a useful tool for identifying hypotheses that can inform a theory-driven evaluation. The hypotheses are represented in a comprehensible way while highlighting the underlying assumptions, and are more easily falsifiable than hypotheses identified without using CLD.

Testing the 'free radical theory of aging' hypothesis: physiological differences in long-lived and short-lived colubrid snakes.

PubMed

Robert, Kylie A; Brunet-Rossinni, Anja; Bronikowski, Anne M

2007-06-01

We test the 'free radical theory of aging' using six species of colubrid snakes (numerous, widely distributed, non-venomous snakes of the family Colubridae) that exhibit long (> 15 years) or short (< 10 years) lifespans. Because the 'rate of living theory' predicts metabolic rates to be correlated with rates of aging and oxidative damage results from normal metabolic processes we sought to answer whether physiological parameters and locomotor performance (which is a good predictor of survival in juvenile snakes) mirrored the evolution of lifespans in these colubrid snakes. We measured whole animal metabolic rate (oxygen consumption Vo2), locomotor performance, cellular metabolic rate (mitochondrial oxygen consumption), and oxidative stress potential (hydrogen peroxide production by mitochondria). Longer-lived colubrid snakes have greater locomotor performance and reduced hydrogen peroxide production than short-lived species, while whole animal metabolic rates and mitochondrial efficiency did not differ with lifespan. We present the first measures testing the 'free radical theory of aging' using reptilian species as model organisms. Using reptiles with different lifespans as model organisms should provide greater insight into mechanisms of aging.

Does human capital matter? A meta-analysis of the relationship between human capital and firm performance.

PubMed

Crook, T Russell; Todd, Samuel Y; Combs, James G; Woehr, David J; Ketchen, David J

2011-05-01

Theory at both the micro and macro level predicts that investments in superior human capital generate better firm-level performance. However, human capital takes time and money to develop or acquire, which potentially offsets its positive benefits. Indeed, extant tests appear equivocal regarding its impact. To clarify what is known, we meta-analyzed effects drawn from 66 studies of the human capital-firm performance relationship and investigated 3 moderators suggested by resource-based theory. We found that human capital relates strongly to performance, especially when the human capital in question is not readily tradable in labor markets and when researchers use operational performance measures that are not subject to profit appropriation. Our results suggest that managers should invest in programs that increase and retain firm-specific human capital.

Time-dependent spin-density-functional-theory description of He+-He collisions

NASA Astrophysics Data System (ADS)

Baxter, Matthew; Kirchner, Tom; Engel, Eberhard

2017-09-01

Theoretical total cross-section results for all ionization and capture processes in the He+-He collision system are presented in the approximate impact energy range of 10-1000 keV/amu. Calculations were performed within the framework of time-dependent spin-density functional theory. The Krieger-Li-Iafrate approximation was used to determine an accurate exchange-correlation potential in the exchange-only limit. The results of two models, one where electron translation factors in the orbitals used to calculate the potential are ignored and another where partial electron translation factors are included, are compared with available experimental data as well as a selection of previous theoretical calculations.

Aerodynamic preliminary analysis system. Part 1: Theory. [linearized potential theory

NASA Technical Reports Server (NTRS)

Bonner, E.; Clever, W.; Dunn, K.

1978-01-01

A comprehensive aerodynamic analysis program based on linearized potential theory is described. The solution treats thickness and attitude problems at subsonic and supersonic speeds. Three dimensional configurations with or without jet flaps having multiple non-planar surfaces of arbitrary planform and open or closed slender bodies of non-circular contour may be analyzed. Longitudinal and lateral-directional static and rotary derivative solutions may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. Nominal case computation time of 45 CPU seconds on the CDC 175 for a 200 panel simulation indicates the program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

Testing general relativity and alternative theories of gravity with space-based atomic clocks and atom interferometers

NASA Astrophysics Data System (ADS)

Bondarescu, Ruxandra; Schärer, Andreas; Jetzer, Philippe; Angélil, Raymond; Saha, Prasenjit; Lundgren, Andrew

2015-05-01

The successful miniaturisation of extremely accurate atomic clocks and atom interferometers invites prospects for satellite missions to perform precision experiments. We discuss the effects predicted by general relativity and alternative theories of gravity that can be detected by a clock, which orbits the Earth. Our experiment relies on the precise tracking of the spacecraft using its observed tick-rate. The spacecraft's reconstructed four-dimensional trajectory will reveal the nature of gravitational perturbations in Earth's gravitational field, potentially differentiating between different theories of gravity. This mission can measure multiple relativistic effects all during the course of a single experiment, and constrain the Parametrized Post-Newtonian Parameters around the Earth. A satellite carrying a clock of fractional timing inaccuracy of Δ f / f ˜ 10-16 in an elliptic orbit around the Earth would constrain the PPN parameters |β - 1|, |γ - 1| ≲ 10-6. We also briefly review potential constraints by atom interferometers on scalar tensor theories and in particular on Chameleon and dilaton models.

Recreational benefits of urban forests: explaining visitors' willingness to pay in the context of the theory of planned behavior.

PubMed

Bernath, Katrin; Roschewitz, Anna

2008-11-01

The extension of contingent valuation models with an attitude-behavior based framework has been proposed in order to improve the descriptive and predictive ability of the models. This study examines the potential of the theory of planned behavior to explain willingness to pay (WTP) in a contingent valuation survey of the recreational benefits of the Zurich city forests. Two aspects of WTP responses, protest votes and bid levels, were analyzed separately. In both steps, models with and without the psychological predictors proposed by the theory of planned behavior were compared. Whereas the inclusion of the psychological predictors significantly improved explanations of protest votes, their ability to improve the performance of the model explaining bid levels was limited. The results indicate that the interpretation of bid levels as behavioral intention may not be appropriate and that the potential of the theory of planned behavior to improve contingent valuation models depends on which aspect of WTP responses is examined.

Towards overcoming the Monte Carlo sign problem with tensor networks

NASA Astrophysics Data System (ADS)

Bañuls, Mari Carmen; Cichy, Krzysztof; Ignacio Cirac, J.; Jansen, Karl; Kühn, Stefan; Saito, Hana

2017-03-01

The study of lattice gauge theories with Monte Carlo simulations is hindered by the infamous sign problem that appears under certain circumstances, in particular at non-zero chemical potential. So far, there is no universal method to overcome this problem. However, recent years brought a new class of non-perturbative Hamiltonian techniques named tensor networks, where the sign problem is absent. In previous work, we have demonstrated that this approach, in particular matrix product states in 1+1 dimensions, can be used to perform precise calculations in a lattice gauge theory, the massless and massive Schwinger model. We have computed the mass spectrum of this theory, its thermal properties and real-time dynamics. In this work, we review these results and we extend our calculations to the case of two flavours and non-zero chemical potential. We are able to reliably reproduce known analytical results for this model, thus demonstrating that tensor networks can tackle the sign problem of a lattice gauge theory at finite density.

Achievement goals and emotions: The mediational roles of perceived progress, control, and value.

PubMed

Hall, Nathan C; Sampasivam, Lavanya; Muis, Krista R; Ranellucci, John

2016-06-01

The link between achievement goals and achievement emotions is well established; however, research exploring potential mediators of this relationship is lacking. The control-value theory of achievement emotions (Pekrun, 2006, Educational Psychology Review, 18, 315) posits that perceptions of control and value mediate the relationship between achievement goals and achievement emotions, whereas the bidirectional theory of affect (Linnenbrink & Pintrich, 2002, Educational Psychologist, 37, 69) proposes that perceived progress mediates this relationship. The present study empirically evaluated three hypothesized mediators of the effects of achievement goals on learning-related emotions as proposed in the control-value theory and the bidirectional theory of affect. Undergraduate students (N = 273) from humanities, social science, and STEM disciplines participated. Participants completed web-based questionnaires evaluating academic achievement goals, perceptions of control, perceived task value, and achievement emotions. Results provided empirical support primarily for perceived progress as a mediator of mastery-approach goal effects on positive emotions (enjoyment, hope), showing indirect effects of mastery- and performance-approach goals on outcome-related emotions (hope, anxiety) via perceived control. Indirect effects of mastery- and performance-approach goals were further observed on anxiety via perceived value, with higher value levels predicting greater anxiety. Study findings partially support Linnenbrink and Pintrich's (2002, Educational Psychologist, 37, 69) bidirectional theory of affect while underscoring the potential for indirect effects of goals on emotions through perceived control as proposed by Pekrun (2006, Educational Psychology Review, 18, 315). © 2016 The British Psychological Society.

Theoretical studies for the rates and kinetic isotope effects of the excited-state double proton transfer in the 1:1 7-azaindole:H2O complex using variational transition state theory including multidimensional tunneling.

PubMed

Duong, My Phu Thi; Kim, Yongho

2010-03-18

Variational transition state theory calculations including multidimensional tunneling (VTST/MT) for excited-state tautomerization in the 1:1 7-azaindole:H(2)O complex were performed. Electronic structures and energies for reactant, product, transition state, and potential energy curves along the reaction coordinate were computed at the CASSCF(10,9)/6-31G(d,p) level of theory. The potential energies were corrected by second-order multireference perturbation theory to take the dynamic electron correlation into consideration. The final potential energy curves along the reaction coordinate were generated at the MRPT2//CASSCF(10,9)/6-31G(d,p) level. Two protons in the excited-state tautomerization are transferred concertedly, albeit asynchronously. The position of the variational transition state is very different from the conventional transition state, and is highly dependent on isotopic substitution. Rate constants were calculated using VTST/MT, and were on the order of 10(-6) s(-1) at room temperature. The HH/DD kinetic isotope effects are consistent with experimental observations; consideration of both tunneling and variational effects was essential to predict the experimental values correctly.

Investigating the importance of self-theories of intelligence and musicality for students' academic and musical achievement.

PubMed

Müllensiefen, Daniel; Harrison, Peter; Caprini, Francesco; Fancourt, Amy

2015-01-01

Musical abilities and active engagement with music have been shown to be positively associated with many cognitive abilities as well as social skills and academic performance in secondary school students. While there is evidence from intervention studies that musical training can be a cause of these positive relationships, recent findings in the literature have suggested that other factors, such as genetics, family background or personality traits, might also be contributing factors. In addition, there is mounting evidence that self-concepts and beliefs can affect academic performance independently of intellectual ability. Students who believe that intelligence is malleable are more likely to attribute poor academic performances to effort rather than ability, and are more likely to take remedial action to improve their performance. However, it is currently not known whether student's beliefs about the nature of musical talent also influence the development of musical abilities in a similar fashion. Therefore, this study introduces a short self-report measure termed "Musical Self-Theories and Goals," closely modeled on validated measures for self-theories in academic scenarios. Using this measure the study investigates whether musical self-theories are related to students' musical development as indexed by their concurrent musical activities and their performance on a battery of listening tests. We use data from a cross-sectional sample of 313 secondary school students to construct a network model describing the relationships between self-theories and academic as well as musical outcome measures, while also assessing potential effects of intelligence and the Big Five personality dimensions. Results from the network model indicate that self-theories of intelligence and musicality are closely related. In addition, both kinds of self-theories are connected to the students' academic achievement through the personality dimension conscientiousness and academic effort. Finally, applying the do-calculus method to the network model we estimate that the size of the assumed causal effects between musical self-theories and academic achievement lie between 0.07 and 0.15 standard deviations.

Renormalization group naturalness of GUT Higgs potentials

NASA Astrophysics Data System (ADS)

Allanach, B. C.; Amelino-Camelia, G.; Philipsen, O.; Pisanti, O.; Rosa, L.

1999-01-01

We analyze the symmetry-breaking patterns of grand unified theories from the point of view of a recently proposed criterion of renormalization-group naturalness. We perform the analysis on simple non-SUSY SU(5) and SO(10) and SUSY SU(5) GUTs. We find that the naturalness criterion can favor spontaneous symmetry breaking in the direction of the smallest of the maximal little groups. Some differences between theories with and without supersymmetry are also emphasized.

Application and Exploration of Big Data Mining in Clinical Medicine.

PubMed

Zhang, Yue; Guo, Shu-Li; Han, Li-Na; Li, Tie-Ling

2016-03-20

To review theories and technologies of big data mining and their application in clinical medicine. Literatures published in English or Chinese regarding theories and technologies of big data mining and the concrete applications of data mining technology in clinical medicine were obtained from PubMed and Chinese Hospital Knowledge Database from 1975 to 2015. Original articles regarding big data mining theory/technology and big data mining's application in the medical field were selected. This review characterized the basic theories and technologies of big data mining including fuzzy theory, rough set theory, cloud theory, Dempster-Shafer theory, artificial neural network, genetic algorithm, inductive learning theory, Bayesian network, decision tree, pattern recognition, high-performance computing, and statistical analysis. The application of big data mining in clinical medicine was analyzed in the fields of disease risk assessment, clinical decision support, prediction of disease development, guidance of rational use of drugs, medical management, and evidence-based medicine. Big data mining has the potential to play an important role in clinical medicine.

Theorizing Strategic Human Resource Development: Linking Financial Performance and Sustainable Competitive Advantage

ERIC Educational Resources Information Center

Hu, Po

2007-01-01

This paper is to explore potential new underlying theory of strategic human resource development based on critiques of current theoretical foundations of HRD. It offers a new definition and model of Strategic HRD based on resource-based view of firm and human resource, with linkage to financial performance and competitiveness. Proposed new model…

Does Human Capital Matter? A Meta-Analysis of the Relationship between Human Capital and Firm Performance

ERIC Educational Resources Information Center

Crook, T. Russell; Todd, Samuel Y.; Combs, James G.; Woehr, David J.; Ketchen, David J., Jr.

2011-01-01

Theory at both the micro and macro level predicts that investments in superior human capital generate better firm-level performance. However, human capital takes time and money to develop or acquire, which potentially offsets its positive benefits. Indeed, extant tests appear equivocal regarding its impact. To clarify what is known, we…

Why does MP2 work?

PubMed

Fink, Reinhold F

2016-11-14

We show analytically and numerically that the performance of second order Møller-Plesset (MP) perturbation theory (PT), coupled-cluster (CC) theory, and other perturbation theory approaches can be rationalized by analyzing the wavefunctions of these methods. While rather large deviations for the individual contributions of configurations to the electron correlation energy are found for MP wavefunctions, they profit from an advantageous and robust error cancellation: The absolute contribution to the correlation energy is generally underestimated for the critical excitations with small energy denominators and all other doubly excited configurations where the two excited electrons are coupled to a singlet. This is balanced by an overestimation of the contribution of triplet-coupled double excitations to the correlation energy. The even better performance of spin-component-scaled-MP2 theory is explained by a similar error compensation effect. The wavefunction analysis for the lowest singlet states of H 2 O, CH 2 , CO, and Cu + shows the predicted trends for MP methods, rapid but biased convergence of CC theory as well as the substantial potential of linearized CC, or retaining the excitation-degree (RE)-PT.

Microsolvation of Cl anion by water clusters: Pertubative Monte Carlo simulations using a hybrid HF/MM potential

NASA Astrophysics Data System (ADS)

Truong, Thanh N.; Stefanovich, Eugene V.

1997-05-01

We present a study of micro-solvation of Cl anion by water clusters of the size up to seven molecules using a perturbative Monte Carlo approach with a hybrid HF/MM potential. In this approach, a perturbation theory was used to avoid performing full SCF calculations at every Monte Carlo step. In this study, the anion is treated quantum mechanically at the HF/6-31G ∗ level of theory while interactions between solvent waters are presented by the TIP3P potential force field. Analysis on the solvent induced dipole moment of the ion indicates that the Cl anion resides most of the time on the surface of the clusters. Accuracy of the perturbative MC approach is also discussed.

Quantitative evaluation of first-order retardation corrections to the quarkonium spectrum

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

Brambilla, N.; Prosperi, G.M.

1992-08-01

We evaluate numerically first-order retardation corrections for some charmonium and bottomonium masses under the usual assumption of a Bethe-Salpeter purely scalar confinement kernel. The result depends strictly on the use of an additional effective potential to express the corrections (rather than to resort to Kato perturbation theory) and on an appropriate regularization prescription. The kernel has been chosen in order to reproduce in the instantaneous approximation a semirelativistic potential suggested by the Wilson loop method. The calculations are performed for two sets of parameters determined by fits in potential theory. The corrections turn out to be typically of the ordermore » of a few hundred MeV and depend on an additional scale parameter introduced in the regularization. A conjecture existing in the literature on the origin of the constant term in the potential is also discussed.« less

Topological Quantum Phase Transition in Synthetic Non-Abelian Gauge Potential: Gauge Invariance and Experimental Detections

PubMed Central

Sun, Fadi; Yu, Xiao-Lu; Ye, Jinwu; Fan, Heng; Liu, Wu-Ming

2013-01-01

The method of synthetic gauge potentials opens up a new avenue for our understanding and discovering novel quantum states of matter. We investigate the topological quantum phase transition of Fermi gases trapped in a honeycomb lattice in the presence of a synthetic non-Abelian gauge potential. We develop a systematic fermionic effective field theory to describe a topological quantum phase transition tuned by the non-Abelian gauge potential and explore its various important experimental consequences. Numerical calculations on lattice scales are performed to compare with the results achieved by the fermionic effective field theory. Several possible experimental detection methods of topological quantum phase transition are proposed. In contrast to condensed matter experiments where only gauge invariant quantities can be measured, both gauge invariant and non-gauge invariant quantities can be measured by experimentally generating various non-Abelian gauges corresponding to the same set of Wilson loops. PMID:23846153

Event-related potential evidence for the processing efficiency theory.

PubMed

Murray, N P; Janelle, C M

2007-01-15

The purpose of this study was to examine the central tenets of the processing efficiency theory using psychophysiological measures of attention and effort. Twenty-eight participants were divided equally into either a high or low trait anxiety group. They were then required to perform a simulated driving task while responding to one of four target light-emitting diodes. Cortical activity and dual task performance were recorded under two conditions -- baseline and competition -- with cognitive anxiety being elevated in the competitive session by an instructional set. Although driving speed was similar across sessions, a reduction in P3 amplitude to cue onset in the light detection task occurred for both groups during the competitive session, suggesting a reduction in processing efficiency as participants became more state anxious. Our findings provide more comprehensive and mechanistic evidence for processing efficiency theory, and confirm that increases in cognitive anxiety can result in a reduction of processing efficiency with little change in performance effectiveness.

Electric-magnetic dualities in non-abelian and non-commutative gauge theories

NASA Astrophysics Data System (ADS)

Ho, Jun-Kai; Ma, Chen-Te

2016-08-01

Electric-magnetic dualities are equivalence between strong and weak coupling constants. A standard example is the exchange of electric and magnetic fields in an abelian gauge theory. We show three methods to perform electric-magnetic dualities in the case of the non-commutative U (1) gauge theory. The first method is to use covariant field strengths to be the electric and magnetic fields. We find an invariant form of an equation of motion after performing the electric-magnetic duality. The second method is to use the Seiberg-Witten map to rewrite the non-commutative U (1) gauge theory in terms of abelian field strength. The third method is to use the large Neveu Schwarz-Neveu Schwarz (NS-NS) background limit (non-commutativity parameter only has one degree of freedom) to consider the non-commutative U (1) gauge theory or D3-brane. In this limit, we introduce or dualize a new one-form gauge potential to get a D3-brane in a large Ramond-Ramond (R-R) background via field redefinition. We also use perturbation to study the equivalence between two D3-brane theories. Comparison of these methods in the non-commutative U (1) gauge theory gives different physical implications. The comparison reflects the differences between the non-abelian and non-commutative gauge theories in the electric-magnetic dualities. For a complete study, we also extend our studies to the simplest abelian and non-abelian p-form gauge theories, and a non-commutative theory with the non-abelian structure.

Effect of the nonlocal exchange on the performance of the orbital-dependent correlation functionals from second-order perturbation theory.

PubMed

Schweigert, Igor V; Bartlett, Rodney J

2008-09-28

Adding a fraction of the nonlocal exchange operator to the local orbital-dependent exchange potential improves the many-body perturbation expansion based on the Kohn-Sham determinant. The effect of such a hybrid scheme on the performance of the orbital-dependent correlation functional from the second-order perturbation theory (PT2H) is investigated numerically. A small fraction of the nonlocal exchange is often sufficient to ensure the existence of the self-consistent solution for the PT2H potential. In the He and Be atoms, including 37% of the nonlocal exchange leads to the correlation energies and electronic densities that are very close to the exact ones. In molecules, varying the fraction of the nonlocal exchange may result in the PT2H energy closely reproducing the CCSD(T) value; however such a fraction depends on the system and does not always result in an accurate electronic density. We also numerically verify that the "semicanonical" perturbation series includes most of the beneficial effects of the nonlocal exchange without sacrificing the locality of the exchange potential.

Combining Theory-Driven Evaluation and Causal Loop Diagramming for Opening the ‘Black Box’ of an Intervention in the Health Sector: A Case of Performance-Based Financing in Western Uganda

PubMed Central

Holvoet, Nathalie; Criel, Bart

2017-01-01

Increased attention on “complexity” in health systems evaluation has resulted in many different methodological responses. Theory-driven evaluations and systems thinking are two such responses that aim for better understanding of the mechanisms underlying given outcomes. Here, we studied the implementation of a performance-based financing intervention by the Belgian Technical Cooperation in Western Uganda to illustrate a methodological strategy of combining these two approaches. We utilized a systems dynamics tool called causal loop diagramming (CLD) to generate hypotheses feeding into a theory-driven evaluation. Semi-structured interviews were conducted with 30 health workers from two districts (Kasese and Kyenjojo) and with 16 key informants. After CLD, we identified three relevant hypotheses: “success to the successful”, “growth and underinvestment”, and “supervision conundrum”. The first hypothesis leads to increasing improvements in performance, as better performance leads to more incentives, which in turn leads to better performance. The latter two hypotheses point to potential bottlenecks. Thus, the proposed methodological strategy was a useful tool for identifying hypotheses that can inform a theory-driven evaluation. The hypotheses are represented in a comprehensible way while highlighting the underlying assumptions, and are more easily falsifiable than hypotheses identified without using CLD. PMID:28869518

Using theory and formative research to design interventions to improve community health worker motivation, retention and performance in Mozambique and Uganda.

PubMed

Strachan, Daniel Llywelyn; Källander, Karin; Nakirunda, Maureen; Ndima, Sozinho; Muiambo, Abel; Hill, Zelee

2015-04-30

Community health workers (CHWs) are increasingly being used in low-income countries to address human resources shortages, yet there remain few effective, evidence-based strategies for addressing the enduring programmatic constraints of worker motivation, retention and performance. This paper describes how two interventions were designed by the Innovations at Scale for Community Access and Lasting Effects (inSCALE) project to address these constraints in Uganda and Mozambique drawing on behavioural theory and formative research results. A review of the work motivation and CHW motivation literature--incorporating influences on retention and performance--was conducted on articles sourced through electronic web searches. Formative research with a focus on the barriers and facilitators to CHW motivation, retention and performance was conducted with community health workers and key stakeholders in Uganda and Mozambique. An analytical induction approach to the thematic analysis of transcripts from 98 in-depth interviews and 26 focus group discussions was adopted across the country settings. From the theoretical review, it was determined that the interventions should promote CHWs as members of a collective by highlighting a sense of shared experience, focus on alignment between worker and programme goals, and emphasise the actions that lead to good performance. The Social Identity Approach was selected as the theory most likely to lead to the development of effective, scalable and sustainable interventions by addressing the identified gap in the literature of the influence of CHW working context. The formative research indicated that CHWs value feedback and feeling connected to the health system and their community, are motivated by status and community standing, and want to be provided with the necessary tools to perform. Two interventions based on these results were developed: a participatory, local community approach and an information communication technology (ICT) approach. Drawing on contextual data and theory that is sensitive to context can potentially lead to the development of appropriate and effective interventions when aiming to improve the motivation, retention and performance of CHWs in Uganda and Mozambique and other comparable settings. Evaluation of the developed interventions is crucial to assess this potential.

Stability derivatives for bodies of revolution at subsonic speeds

NASA Technical Reports Server (NTRS)

Liu, D. D.; Platzer, M. F.; Ruo, S. Y.

1976-01-01

The paper considers a rigid pointed body of revolution in a steady uniform subsonic flow. The body performs harmonic small-amplitude pitching oscillations around its zero angle of attack position. The body is assumed to be smooth and sufficiently slender so that the small perturbation concept can be applied. The basis of the method used, following Revell (1960), is the relation of a body-fixed perturbation potential to the general velocity potential. Normal force distributions as well as total force and moment coefficients are calculated for parabolic spindles and the numerical results show good agreement between Revell's second-order slender body theory and the present theory for the static stability derivatives of the parabolic spindles.

The role of Area 10 (BA10) in human multitasking and in social cognition: a lesion study.

PubMed

Roca, María; Torralva, Teresa; Gleichgerrcht, Ezequiel; Woolgar, Alexandra; Thompson, Russell; Duncan, John; Manes, Facundo

2011-11-01

A role for rostral prefrontal cortex (BA10) has been proposed in multitasking, in particular, the selection and maintenance of higher order internal goals while other sub-goals are being performed. BA10 has also been implicated in the ability to infer someone else's feelings and thoughts, often referred to as theory of mind. While most of the data to support these views come from functional neuroimaging studies, lesion studies are scant. In the present study, we compared the performance of a group of frontal patients whose lesions involved BA10, a group of frontal patients whose lesions did not affect this area (nonBA10), and a group of healthy controls on tests requiring multitasking and complex theory of mind judgments. Only the group with lesions involving BA10 showed deficits on multitasking and theory of mind tasks when compared with control subjects. NonBA10 patients performed more poorly than controls on an executive function screening tool, particularly on measures of response inhibition and abstract reasoning, suggesting that theory of mind and multitasking deficits following lesions to BA10 cannot be explained by a general worsening of executive function. In addition, we searched for correlations between performance and volume of damage within different subregions of BA10. Significant correlations were found between multitasking performance and volume of damage in right lateral BA10, and between theory of mind and total BA10 lesion volume. These findings stress the potential pivotal role of BA10 in higher order cognitive functions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Motivational Support in Web 2.0 Learning Environments: A Regression Analysis Based on the Integrative Theory of Motivation, Volition and Performance

ERIC Educational Resources Information Center

Huang, Wen-Hao David; Hood, Denice Ward; Yoo, Sun Joo

2014-01-01

Web 2.0 applications have been widely applied for teaching and learning in US higher education in recent years. Their potential impact on learning motivation and learner performance, however, has not attracted substantial research efforts. To better understand how Web 2.0 applications might impact learners' motivation in higher education…

Independence: proposing an initial framework for occupational therapy.

PubMed

Collins, Bethan

2017-11-01

The concept of independence is common in occupational therapy theory and practice but has rarely been clearly defined or conceptualized within in occupational therapy literature and there seems to be no standard definition. This can result in ambiguity, which potentially jeopardizes client-centred practice. This paper proposes an occupational therapy independence framework (OTIF) that synthesizes the range of characterizations of independence in a practically useful and occupation-centred manner. A review of literature, clinical experience, doctoral research and conversations with occupational therapists and disabled people, in particular those involved in a disability activism group and people with physical disabilities, has led to the development of the OTIF. Independence and interdependence, as characterized in the OTIF, occur when an individual exerts choice over occupational performance and can engage in occupations in a manner acceptable to the individual. Interdependence results when occupations are performed with another person whereas independence involves solitary occupational performance. Dependence typically results from inability to choose occupations or a mismatch between performance capacity and environmental factors. The OTIF has the potential to clarify the conceptualization of independence within occupational therapy theory and practice. This initial proposal is presented to stimulate debate and discussion.

Analysis of superconducting electromagnetic finite elements based on a magnetic vector potential variational principle

NASA Technical Reports Server (NTRS)

Schuler, James J.; Felippa, Carlos A.

1991-01-01

Electromagnetic finite elements are extended based on a variational principle that uses the electromagnetic four potential as primary variable. The variational principle is extended to include the ability to predict a nonlinear current distribution within a conductor. The extension of this theory is first done on a normal conductor and tested on two different problems. In both problems, the geometry remains the same, but the material properties are different. The geometry is that of a 1-D infinite wire. The first problem is merely a linear control case used to validate the new theory. The second problem is made up of linear conductors with varying conductivities. Both problems perform well and predict current densities that are accurate to within a few ten thousandths of a percent of the exact values. The fourth potential is then removed, leaving only the magnetic vector potential, and the variational principle is further extended to predict magnetic potentials, magnetic fields, the number of charge carriers, and the current densities within a superconductor. The new element produces good results for the mean magnetic field, the vector potential, and the number of superconducting charge carriers despite a relatively high system condition number. The element did not perform well in predicting the current density. Numerical problems inherent to this formulation are explored and possible remedies to produce better current predicting finite elements are presented.

Force-field functor theory: classical force-fields which reproduce equilibrium quantum distributions

PubMed Central

Babbush, Ryan; Parkhill, John; Aspuru-Guzik, Alán

2013-01-01

Feynman and Hibbs were the first to variationally determine an effective potential whose associated classical canonical ensemble approximates the exact quantum partition function. We examine the existence of a map between the local potential and an effective classical potential which matches the exact quantum equilibrium density and partition function. The usefulness of such a mapping rests in its ability to readily improve Born-Oppenheimer potentials for use with classical sampling. We show that such a map is unique and must exist. To explore the feasibility of using this result to improve classical molecular mechanics, we numerically produce a map from a library of randomly generated one-dimensional potential/effective potential pairs then evaluate its performance on independent test problems. We also apply the map to simulate liquid para-hydrogen, finding that the resulting radial pair distribution functions agree well with path integral Monte Carlo simulations. The surprising accessibility and transferability of the technique suggest a quantitative route to adapting Born-Oppenheimer potentials, with a motivation similar in spirit to the powerful ideas and approximations of density functional theory. PMID:24790954

Current-Voltage and Floating-Potential characteristics of cylindrical emissive probes from a full-kinetic model based on the orbital motion theory

NASA Astrophysics Data System (ADS)

Chen, Xin; Sánchez-Arriaga, Gonzalo

2018-02-01

To model the sheath structure around an emissive probe with cylindrical geometry, the Orbital-Motion theory takes advantage of three conserved quantities (distribution function, transverse energy, and angular momentum) to transform the stationary Vlasov-Poisson system into a single integro-differential equation. For a stationary collisionless unmagnetized plasma, this equation describes self-consistently the probe characteristics. By solving such an equation numerically, parametric analyses for the current-voltage (IV) and floating-potential (FP) characteristics can be performed, which show that: (a) for strong emission, the space-charge effects increase with probe radius; (b) the probe can float at a positive potential relative to the plasma; (c) a smaller probe radius is preferred for the FP method to determine the plasma potential; (d) the work function of the emitting material and the plasma-ion properties do not influence the reliability of the floating-potential method. Analytical analysis demonstrates that the inflection point of an IV curve for non-emitting probes occurs at the plasma potential. The flat potential is not a self-consistent solution for emissive probes.

Dedicated clock/timing-circuit theories of time perception and timed performance.

PubMed

van Rijn, Hedderik; Gu, Bon-Mi; Meck, Warren H

2014-01-01

Scalar Timing Theory (an information-processing version of Scalar Expectancy Theory) and its evolution into the neurobiologically plausible Striatal Beat-Frequency (SBF) theory of interval timing are reviewed. These pacemaker/accumulator or oscillation/coincidence detection models are then integrated with the Adaptive Control of Thought-Rational (ACT-R) cognitive architecture as dedicated timing modules that are able to make use of the memory and decision-making mechanisms contained in ACT-R. The different predictions made by the incorporation of these timing modules into ACT-R are discussed as well as the potential limitations. Novel implementations of the original SBF model that allow it to be incorporated into ACT-R in a more fundamental fashion than the earlier simulations of Scalar Timing Theory are also considered in conjunction with the proposed properties and neural correlates of the "internal clock".

Theory-of-mind understanding and theory-of-mind use in unaffected first-degree relatives of schizophrenia and bipolar disorder.

PubMed

Wang, Yong-Guang; Roberts, David L; Liang, Yan; Shi, Jian-Fei; Wang, Kai

2015-12-15

We assessed theory of mind (ToM) in unaffected first-degree relatives (FDR) of patients with schizophrenia (SC) and bipolar disorder (BD) compared to healthy controls with a revised computerized referential communication task. Results showed that FDR of SC performed worse than FDR of BD and controls on a task requiring ToM-use, but not on a task requiring ToM-understanding. This indicates that deficient ToM-use, rather than ToM-understanding impairments, may represent a potential candidate endophenotype for schizophrenia. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Equilibrium finite-frequency noise of an interacting mesoscopic capacitor studied in time-dependent density functional theory

NASA Astrophysics Data System (ADS)

Dittmann, Niklas; Splettstoesser, Janine; Helbig, Nicole

2018-03-01

We calculate the frequency-dependent equilibrium noise of a mesoscopic capacitor in time-dependent density functional theory (TDDFT). The capacitor is modeled as a single-level quantum dot with on-site Coulomb interaction and tunnel coupling to a nearby reservoir. The noise spectra are derived from linear-response conductances via the fluctuation-dissipation theorem. Thereby, we analyze the performance of a recently derived exchange-correlation potential with time-nonlocal density dependence in the finite-frequency linear-response regime. We compare our TDDFT noise spectra with real-time perturbation theory and find excellent agreement for noise frequencies below the reservoir temperature.

Judith Butler's theories: reflections for nursing research and practice.

PubMed

Nagington, Maurice G

2016-10-01

Judith Butler is one of the most influential late 20th and early 21st century philosophers in regard to left wing politics, as well as an active campaigner for social justice within the United States and worldwide. Her academic work has been foundational to the academic discipline of queer theory and has been extensively critiqued and applied across a hugely wide range of disciplines. In addition, Butler's work itself is extensive covering topics such as gender, sexuality, race, literary theory, and warfare. This article can only serve as a taster for the potential application of her work in relation to nursing, which is in its infancy. This introduction covers three of the potentially most productive themes in Butler's work, namely power, performativity, and ethics. Each of these themes are critically explored in turn, sometimes in relation to their actual application in nursing literature, but also in relation to their potential for producing novel critiques of nursing practice. Suggestions are made about how Butler's work can develop nursing research and practice. The article concludes with a short summary of Butler's key works as well as suggested reading for people interested in examining how her theories have been applied across different academic settings. © 2016 John Wiley & Sons Ltd.

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

Catterall, Simon; Veernala, Aarti

We construct a lattice theory with one exact supersymmetry which consists of fields transforming in both the adjoint and fundamental representations of a U(Nc) gauge group. In addition to gluons and gluinos, the theory contains Nf flavors of fermion in the fundamental representation along with their scalar partners and is invariant under a global U(Nf) flavor symmetry. The lattice action contains an additional Fayet-Iliopoulos term which can be used to generate a scalar potential. We perform numerical simulations that corroborate the theoretical expectation that supersymmetry is spontaneously broken for Nf

Testing a lepton quarticity flavor theory of neutrino oscillations with the DUNE experiment

NASA Astrophysics Data System (ADS)

Srivastava, Rahul; Ternes, Christoph A.; Tórtola, Mariam; Valle, José W. F.

2018-03-01

Oscillation studies play a central role in elucidating at least some aspects of the flavor problem. Here we examine the status of the predictions of a lepton quarticity flavor theory of neutrino oscillations against the existing global sample of oscillation data. By performing quantitative simulations we also determine the potential of the upcoming DUNE experiment in narrowing down the currently ill-measured oscillation parameters θ23 and δCP. We present the expected improved sensitivity on these parameters for different assumptions.

Ling's Adsorption Theory as a Mechanism of Membrane Potential Generation Observed in Both Living and Nonliving Systems.

PubMed

Tamagawa, Hirohisa; Funatani, Makoto; Ikeda, Kota

2016-01-26

The potential between two electrolytic solutions separated by a membrane impermeable to ions was measured and the generation mechanism of potential measured was investigated. From the physiological point of view, a nonzero membrane potential or action potential cannot be observed across the impermeable membrane. However, a nonzero membrane potential including action potential-like potential was clearly observed. Those observations gave rise to a doubt concerning the validity of currently accepted generation mechanism of membrane potential and action potential of cell. As an alternative theory, we found that the long-forgotten Ling's adsorption theory was the most plausible theory. Ling's adsorption theory suggests that the membrane potential and action potential of a living cell is due to the adsorption of mobile ions onto the adsorption site of cell, and this theory is applicable even to nonliving (or non-biological) system as well as living system. Through this paper, the authors emphasize that it is necessary to reconsider the validity of current membrane theory and also would like to urge the readers to pay keen attention to the Ling's adsorption theory which has for long years been forgotten in the history of physiology.

Application and Exploration of Big Data Mining in Clinical Medicine

PubMed Central

Zhang, Yue; Guo, Shu-Li; Han, Li-Na; Li, Tie-Ling

2016-01-01

Objective: To review theories and technologies of big data mining and their application in clinical medicine. Data Sources: Literatures published in English or Chinese regarding theories and technologies of big data mining and the concrete applications of data mining technology in clinical medicine were obtained from PubMed and Chinese Hospital Knowledge Database from 1975 to 2015. Study Selection: Original articles regarding big data mining theory/technology and big data mining's application in the medical field were selected. Results: This review characterized the basic theories and technologies of big data mining including fuzzy theory, rough set theory, cloud theory, Dempster–Shafer theory, artificial neural network, genetic algorithm, inductive learning theory, Bayesian network, decision tree, pattern recognition, high-performance computing, and statistical analysis. The application of big data mining in clinical medicine was analyzed in the fields of disease risk assessment, clinical decision support, prediction of disease development, guidance of rational use of drugs, medical management, and evidence-based medicine. Conclusion: Big data mining has the potential to play an important role in clinical medicine. PMID:26960378

Dynamics and Thermodynamics of Quantum Crystals Near the Instability Point in the Self-Consistent Phonon Theory

DTIC Science & Technology

2001-01-01

Buckingham (B), Lennard - Jones (LI ) and Morse (M) potential energy parameters of solid helium and neon calculated with the help of experimental data for the...Using the values of potential energy parameters given in Table 1 for the Buckingham (Eq.(3)), Lennard - Jones (Eq.(4)) and the Morse (Eq.(5)) s.c...calculations are performed in terms of the (expm) Buckingham, the (n,m) Lennard - Jones and the (expexp) Morse self-consistent potentials as

Fast Model Generalized Pseudopotential Theory Interatomic Potential Routine

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

2015-03-18

MGPT is an unclassified source code for the fast evaluation and application of quantum-based MGPT interatomic potentials for mrtals. The present version of MGPT has been developed entirely at LLNL, but is specifically designed for implementation in the open-source molecular0dynamics code LAMMPS maintained by Sandia National Laboratories. Using MGPT in LAMMPS, with separate input potential data, one can perform large-scale atomistic simulations of the structural, thermodynamic, defeat and mechanical properties of transition metals with quantum-mechanical realism.

Investigating the importance of self-theories of intelligence and musicality for students' academic and musical achievement

PubMed Central

Müllensiefen, Daniel; Harrison, Peter; Caprini, Francesco; Fancourt, Amy

2015-01-01

Musical abilities and active engagement with music have been shown to be positively associated with many cognitive abilities as well as social skills and academic performance in secondary school students. While there is evidence from intervention studies that musical training can be a cause of these positive relationships, recent findings in the literature have suggested that other factors, such as genetics, family background or personality traits, might also be contributing factors. In addition, there is mounting evidence that self-concepts and beliefs can affect academic performance independently of intellectual ability. Students who believe that intelligence is malleable are more likely to attribute poor academic performances to effort rather than ability, and are more likely to take remedial action to improve their performance. However, it is currently not known whether student's beliefs about the nature of musical talent also influence the development of musical abilities in a similar fashion. Therefore, this study introduces a short self-report measure termed “Musical Self-Theories and Goals,” closely modeled on validated measures for self-theories in academic scenarios. Using this measure the study investigates whether musical self-theories are related to students' musical development as indexed by their concurrent musical activities and their performance on a battery of listening tests. We use data from a cross-sectional sample of 313 secondary school students to construct a network model describing the relationships between self-theories and academic as well as musical outcome measures, while also assessing potential effects of intelligence and the Big Five personality dimensions. Results from the network model indicate that self-theories of intelligence and musicality are closely related. In addition, both kinds of self-theories are connected to the students' academic achievement through the personality dimension conscientiousness and academic effort. Finally, applying the do-calculus method to the network model we estimate that the size of the assumed causal effects between musical self-theories and academic achievement lie between 0.07 and 0.15 standard deviations. PMID:26594189

Exploring the motivation jungle: predicting performance on a novel task by investigating constructs from different motivation perspectives in tandem.

PubMed

Van Nuland, Hanneke J C; Dusseldorp, Elise; Martens, Rob L; Boekaerts, Monique

2010-08-01

Different theoretical viewpoints on motivation make it hard to decide which model has the best potential to provide valid predictions on classroom performance. This study was designed to explore motivation constructs derived from different motivation perspectives that predict performance on a novel task best. Motivation constructs from self-determination theory, self-regulation theory, and achievement goal theory were investigated in tandem. Performance was measured by systematicity (i.e. how systematically students worked on a problem-solving task) and test score (i.e. score on a multiple-choice test). Hierarchical regression analyses on data from 259 secondary school students showed a quadratic relation between a performance avoidance orientation and both performance outcomes, indicating that extreme high and low performance avoidance resulted in the lowest performance. Furthermore, two three-way interaction effects were found. Intrinsic motivation seemed to play a key role in test score and systematicity performance, provided that effort regulation and metacognitive skills were both high. Results indicate that intrinsic motivation in itself is not enough to attain a good performance. Instead, a moderate score on performance avoidance, together with the ability to remain motivated and effectively regulate and control task behavior, is needed to attain a good performance. High time management skills also contributed to higher test score and systematicity performance and a low performance approach orientation contributed to higher systematicity performance. We concluded that self-regulatory skills should be trained in order to have intrinsically motivated students perform well on novel tasks in the classroom.

An efficient finite element with layerwise mechanics for smart piezoelectric composite and sandwich shallow shells

NASA Astrophysics Data System (ADS)

Yasin, M. Yaqoob; Kapuria, S.

2014-01-01

In this work, we present a new efficient four-node finite element for shallow multilayered piezoelectric shells, considering layerwise mechanics and electromechanical coupling. The laminate mechanics is based on the zigzag theory that has only seven kinematic degrees of freedom per node. The normal deformation of the piezoelectric layers under the electric field is accounted for without introducing any additional deflection variables. A consistent quadratic variation of the electric potential across the piezoelectric layers with the provision of satisfying the equipotential condition of electroded surfaces is adopted. The performance of the new element is demonstrated for the static response under mechanical and electric potential loads, and for free vibration response of smart shells under different boundary conditions. The predictions are found to be very close to the three dimensional piezoelasticity solutions for hybrid shells made of not only single-material composite substrates, but also sandwich substrates with a soft core for which the equivalent single layer (ESL) theories perform very badly.

Performance on verbal and low-verbal false belief tasks: evidence from children with Williams syndrome.

PubMed

Van Herwegen, Jo; Dimitriou, Dagmara; Rundblad, Gabriella

2013-01-01

Previous studies that have investigated the relationship between performance on theory of mind (ToM) tasks and verbal abilities in individuals with Williams syndrome (WS) have reported contradictory findings with some showing that language abilities aid performance on ToM tasks while others have found that participants with WS fail these tasks because of their verbal demands. The current study investigated this relationship again comparing performance on a classical change-location task to two newly developed low-verbal tasks, one change-location task and one unexpected content task. Thirty children with WS (aged 5-17;01 years) and 30 typically developing (TD) children (aged between 2;10 years and 9;09 years), who were matched for vocabulary comprehension scores were included in the study. Although performance in the WS group was significantly poorer compared to the TD group on all three tasks, performance was not predicted by their receptive vocabulary or grammatical ability scores. In addition, ToM abilities in both groups depended on the cognitive demands of the task at hand. This finding shows that performance on ToM tasks in WS is not necessarily hindered by their delayed language abilities but rather by the task administered. This could potentially affect the diagnosis of developmental disorders, such as Autism Spectrum Disorders, and comparison of ToM abilities across developmental disorders. Readers of this article should be able to (1) describe the current state of theory of mind research in Williams syndrome, (2) identify which cognitive abilities might explain performance on theory of mind tasks in both typically developing children and in children with Williams syndrome, and (3) interpret the importance of task demands when assessing children's theory of mind abilities. Copyright © 2013 Elsevier Inc. All rights reserved.

“UTILIZING” SIGNAL DETECTION THEORY

PubMed Central

Lynn, Spencer K.; Barrett, Lisa Feldman

2014-01-01

What do inferring what a person is thinking or feeling, deciding to report a symptom to your doctor, judging a defendant’s guilt, and navigating a dimly lit room have in common? They involve perceptual uncertainty (e.g., a scowling face might indicate anger or concentration, which engender different appropriate responses), and behavioral risk (e.g., a cost to making the wrong response). Signal detection theory describes these types of decisions. In this tutorial we show how, by incorporating the economic concept of utility, signal detection theory serves as a model of optimal decision making, beyond its common use as an analytic method. This utility approach to signal detection theory highlights potentially enigmatic influences of perceptual uncertainty on measures of decision-making performance (accuracy and optimality) and on behavior (a functional relationship between bias and sensitivity). A “utilized” signal detection theory offers the possibility of expanding the phenomena that can be understood within a decision-making framework. PMID:25097061

The Topological Field Theory of Data: a program towards a novel strategy for data mining through data language

NASA Astrophysics Data System (ADS)

Rasetti, M.; Merelli, E.

2015-07-01

This paper aims to challenge the current thinking in IT for the 'Big Data' question, proposing - almost verbatim, with no formulas - a program aiming to construct an innovative methodology to perform data analytics in a way that returns an automaton as a recognizer of the data language: a Field Theory of Data. We suggest to build, directly out of probing data space, a theoretical framework enabling us to extract the manifold hidden relations (patterns) that exist among data, as correlations depending on the semantics generated by the mining context. The program, that is grounded in the recent innovative ways of integrating data into a topological setting, proposes the realization of a Topological Field Theory of Data, transferring and generalizing to the space of data notions inspired by physical (topological) field theories and harnesses the theory of formal languages to define the potential semantics necessary to understand the emerging patterns.

Electromechanical instability in soft materials: Theory, experiments and applications

NASA Astrophysics Data System (ADS)

Suo, Zhigang

2013-03-01

Subject to a voltage, a membrane of a dielectric elastomer reduces thickness and expands area, possibly straining over 100%. The phenomenon is being developed as transducers for broad applications, including soft robots, adaptive optics, Braille displays, and electric generators. The behavior of dielectric elastomers is closely tied to electromechanical instability. This instability may limit the performance of devices, and may also be used to achieve giant actuation strains. This talk reviews the theory of dielectric elastomers, coupling large deformation and electric potential. The theory is developed within the framework of continuum mechanics and thermodynamics. The theory attempts to answer commonly asked questions. How do mechanics and electrostatics work together to generate large deformation? How efficiently can a material convert energy from one form to another? How do molecular processes affect macroscopic behavior? The theory is used to describe electromechanical instability, and is related to recent experiments.

The fourth dimension: A motoric perspective on the anxiety–performance relationship

PubMed Central

Carson, Howie J.; Collins, Dave

2016-01-01

ABSTRACT This article focuses on raising concern that anxiety–performance relationship theory has insufficiently catered for motoric issues during, primarily, closed and self-paced skill execution (e.g., long jump and javelin throw). Following a review of current theory, we address the under-consideration of motoric issues by extending the three-dimensional model put forward by Cheng, Hardy, and Markland (2009) (‘Toward a three-dimensional conceptualization of performance anxiety: Rationale and initial measurement development, Psychology of Sport and Exercise, 10, 271–278). This fourth dimension, termed skill establishment, comprises the level and consistency of movement automaticity together with a performer's confidence in this specific process, as providing a degree of robustness against negative anxiety effects. To exemplify this motoric influence, we then offer insight regarding current theories’ misrepresentation that a self-focus of attention toward an already well-learned skill always leads to a negative performance effect. In doing so, we draw upon applied literature to distinguish between positive and negative self-foci and suggest that on what and how a performer directs their attention is crucial to the interaction with skill establishment and, therefore, performance. Finally, implications for skill acquisition research are provided. Accordingly, we suggest a positive potential flow from applied/translational to fundamental/theory-generating research in sport which can serve to freshen and usefully redirect investigation into this long-considered but still insufficiently understood concept. PMID:26692896

Motivation to learn: an overview of contemporary theories.

PubMed

Cook, David A; Artino, Anthony R

2016-10-01

To succinctly summarise five contemporary theories about motivation to learn, articulate key intersections and distinctions among these theories, and identify important considerations for future research. Motivation has been defined as the process whereby goal-directed activities are initiated and sustained. In expectancy-value theory, motivation is a function of the expectation of success and perceived value. Attribution theory focuses on the causal attributions learners create to explain the results of an activity, and classifies these in terms of their locus, stability and controllability. Social- cognitive theory emphasises self-efficacy as the primary driver of motivated action, and also identifies cues that influence future self-efficacy and support self-regulated learning. Goal orientation theory suggests that learners tend to engage in tasks with concerns about mastering the content (mastery goal, arising from a 'growth' mindset regarding intelligence and learning) or about doing better than others or avoiding failure (performance goals, arising from a 'fixed' mindset). Finally, self-determination theory proposes that optimal performance results from actions motivated by intrinsic interests or by extrinsic values that have become integrated and internalised. Satisfying basic psychosocial needs of autonomy, competence and relatedness promotes such motivation. Looking across all five theories, we note recurrent themes of competence, value, attributions, and interactions between individuals and the learning context. To avoid conceptual confusion, and perhaps more importantly to maximise the theory-building potential of their work, researchers must be careful (and precise) in how they define, operationalise and measure different motivational constructs. We suggest that motivation research continue to build theory and extend it to health professions domains, identify key outcomes and outcome measures, and test practical educational applications of the principles thus derived. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Dynamics of modularity of neural activity in the brain during development

NASA Astrophysics Data System (ADS)

Deem, Michael; Chen, Man

2014-03-01

Theory suggests that more modular systems can have better response functions at short times. This theory suggests that greater cognitive performance may be achieved for more modular neural activity, and that modularity of neural activity may, therefore, likely increase with development in children. We study the relationship between age and modularity of brain neural activity in developing children. The value of modularity calculated from fMRI data is observed to increase during childhood development and peak in young adulthood. We interpret these results as evidence of selection for plasticity in the cognitive function of the human brain. We present a model to illustrate how modularity can provide greater cognitive performance at short times and enhance fast, low-level, automatic cognitive processes. Conversely, high-level, effortful, conscious cognitive processes may not benefit from modularity. We use quasispecies theory to predict how the average modularity evolves with age, given a fitness function extracted from the model. We suggest further experiments exploring the effect of modularity on cognitive performance and suggest that modularity may be a potential biomarker for injury, rehabilitation, or disease.

Examining the influence of psychopathy, hostility biases, and automatic processing on criminal offenders' Theory of Mind.

PubMed

Nentjes, Lieke; Bernstein, David; Arntz, Arnoud; van Breukelen, Gerard; Slaats, Mariëtte

2015-01-01

Theory of Mind (ToM) is a social perceptual skill that refers to the ability to take someone else's perspective and infer what others think. The current study examined the effect of potential hostility biases, as well as controlled (slow) versus automatic (fast) processing on ToM performance in psychopathy. ToM abilities (as assessed with the Reading the Mind in the Eyes Test; RMET; Baron-Cohen, Wheelwright, Hill, Raste, & Plumb, 2001), was compared between 39 PCL-R diagnosed psychopathic offenders, 37 non-psychopathic offenders, and 26 nonoffender controls. Contrary to our hypothesis, psychopathic individuals presented with intact overall RMET performance when restrictions were imposed on how long task stimuli could be processed. In addition, psychopaths did not over-ascribe hostility to task stimuli (i.e., lack of hostility bias). However, there was a significant three-way interaction between hostility, processing speed, and psychopathy: when there was no time limit on stimulus presentation, psychopathic offenders made fewer errors in identifying more hostile eye stimuli compared to nonoffender controls, who seemed to be less accurate in detecting hostility. Psychopaths' more realistic appraisal of others' malevolent mental states is discussed in the light of theories that stress its potential adaptive function. Copyright © 2015 Elsevier Ltd. All rights reserved.

Neural Bases of Automaticity

ERIC Educational Resources Information Center

Servant, Mathieu; Cassey, Peter; Woodman, Geoffrey F.; Logan, Gordon D.

2018-01-01

Automaticity allows us to perform tasks in a fast, efficient, and effortless manner after sufficient practice. Theories of automaticity propose that across practice processing transitions from being controlled by working memory to being controlled by long-term memory retrieval. Recent event-related potential (ERP) studies have sought to test this…

Are anxious workers less productive workers? It depends on the quality of social exchange.

PubMed

McCarthy, Julie M; Trougakos, John P; Cheng, Bonnie Hayden

2016-02-01

In this article, we draw from Conservation of Resources Theory to advance and test a framework which predicts that emotional exhaustion plays an explanatory role underlying the relation between workplace anxiety and job performance. Further, we draw from social exchange theories to predict that leader-member exchange and coworker exchange will mitigate the harmful effects of anxiety on job performance. Findings across a 3-wave study of police officers supported our model. Emotional exhaustion mediated the link between workplace anxiety and job performance, over and above the effect of cognitive interference. Further, coworker exchange mitigated the positive relation between anxiety and emotional exhaustion, while leader-member exchange mitigated the negative relation between emotional exhaustion and job performance. This study elucidates the effects of workplace anxiety on resource depletion via emotional exhaustion and highlights the value of drawing on social resources to offset the potentially harmful effects of workplace anxiety on job performance. (c) 2016 APA, all rights reserved).

Doping Attitudes and Covariates of Potential Doping Behaviour in High-Level Team-Sport Athletes; Gender Specific Analysis.

PubMed

Sekulic, Damir; Tahiraj, Enver; Zvan, Milan; Zenic, Natasa; Uljevic, Ognjen; Lesnik, Blaz

2016-12-01

Team sports are rarely studied with regard to doping behaviour and doping-related factors regardless of their global popularity. This study aimed to investigate doping factors and covariates of potential doping behaviour in high-level team-sport athletes. The subjects were 457 high-performing, national- and international-level athletes (21.9 ± 3.4 years of age; 179 females) involved in volleyball (n = 77), soccer (n = 163), basketball (n = 114) and handball (n = 103). Previously validated self-administered questionnaires aimed at evidencing sport factors, doping-related factors, knowledge on sport nutrition and doping, and attitudes to performance enhancement were used. The results indicated a higher doping likelihood in male athletes, with a significant gender difference for basketball and handball. In males, a higher doping likelihood is found for athletes who had achieved better results at junior-age level, those who regularly consume dietary supplements, and who perceive their sport as being contaminated by doping. A higher sport achievement at senior-age level is protective against potential doping behaviour in males. In females, a higher likelihood of doping is evidenced in those athletes involved in binge drinking, while a lower tendency for doping is evidenced in female athletes who possess better knowledge on sport nutrition. Knowledge about doping is very low and thus education about doping is urgently needed. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in females. Future studies should consider other approaches and theories, such as theory of planned behaviour and/or social-cognitive theory, in studying the problem of doping behaviour in team-sports.

Reference interaction site model and optimized perturbation theories of colloidal dumbbells with increasing anisotropy

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

Munaò, Gianmarco, E-mail: gmunao@unime.it; Costa, Dino; Caccamo, Carlo

We investigate thermodynamic properties of anisotropic colloidal dumbbells in the frameworks provided by the Reference Interaction Site Model (RISM) theory and an Optimized Perturbation Theory (OPT), this latter based on a fourth-order high-temperature perturbative expansion of the free energy, recently generalized to molecular fluids. Our model is constituted by two identical tangent hard spheres surrounded by square-well attractions with same widths and progressively different depths. Gas-liquid coexistence curves are obtained by predicting pressures, free energies, and chemical potentials. In comparison with previous simulation results, RISM and OPT agree in reproducing the progressive reduction of the gas-liquid phase separation as themore » anisotropy of the interaction potential becomes more pronounced; in particular, the RISM theory provides reasonable predictions for all coexistence curves, bar the strong anisotropy regime, whereas OPT performs generally less well. Both theories predict a linear dependence of the critical temperature on the interaction strength, reproducing in this way the mean-field behavior observed in simulations; the critical density—that drastically drops as the anisotropy increases—turns to be less accurate. Our results appear as a robust benchmark for further theoretical studies, in support to the simulation approach, of self-assembly in model colloidal systems.« less

On holographic Rényi entropy in some modified theories of gravity

NASA Astrophysics Data System (ADS)

Dey, Anshuman; Roy, Pratim; Sarkar, Tapobrata

2018-04-01

We perform a detailed analysis of holographic entanglement Rényi entropy in some modified theories of gravity with four dimensional conformal field theory duals. First, we construct perturbative black hole solutions in a recently proposed model of Einsteinian cubic gravity in five dimensions, and compute the Rényi entropy as well as the scaling dimension of the twist operators in the dual field theory. Consistency of these results are verified from the AdS/CFT correspondence, via a corresponding computation of the Weyl anomaly on the gravity side. Similar analyses are then carried out for three other examples of modified gravity in five dimensions that include a chemical potential, namely Born-Infeld gravity, charged quasi-topological gravity and a class of Weyl corrected gravity theories with a gauge field, with the last example being treated perturbatively. Some interesting bounds in the dual conformal field theory parameters in quasi-topological gravity are pointed out. We also provide arguments on the validity of our perturbative analysis, whenever applicable.

Flux compactification of M-theory on compact manifolds with spin(7) holonomy

NASA Astrophysics Data System (ADS)

Constantin, Dragos Eugeniu

2005-11-01

At the leading order, M-theory admits minimal supersymmetric compactifications if the internal manifold has exceptional holonomy. The inclusion of non-vanishing fluxes in M-theory and string theory compactifications induce a superpotential in the lower dimensional theory, which depends on the fluxes. In this work, we check the conjectured form of this superpotential in the case of warped M-theory compactifications on Spin (7) holonomy manifolds. We perform a Kaluza-Klein reduction of the eleven-dimensional supersymmetry transformation for the gravitino and we find by direct comparison the superpotential expression. We check the conjecture for the heterotic string compactified on a Calabi-Yau three-fold as well. The conjecture can be checked indirectly by inspecting the scalar potential obtained after the compactification of M-theory on Spin (7) holonomy manifolds with non-vanishing fluxes. The scalar potential can be written in terms of the superpotential and we show that this potential stabilizes all the moduli fields describing deformations of the metric except for the radial modulus. All the above analyses require the knowledge of the minimal supergravity action in three dimensions. Therefore we calculate the most general causal N = 1 three-dimensional, gauge invariant action coupled to matter in superspace and derive its component form using Ectoplasmic integration theory. We also show that the three-dimensional theory which results from the compactification is in agreement with the more general supergravity construction. The compactification procedure takes into account higher order quantum correction terms in the low energy effective action. We analyze the properties of these terms on a Spin (7) background. We derive a perturbative set of solutions which emerges from a warped compactification on a Spin (7) holonomy manifold with non-vanishing flux for the M-theory field strength and we show that in general the Ricci flatness of the internal manifold is lost, which means that the supergravity vacua are deformed away from the exceptional holonomy. Using the superpotential form we identify the supersymmetric vacua out of this general set of solutions.

Social epidemiology of a large outbreak of chickenpox in the Colombian sugar cane producer region: a set theory-based analysis.

PubMed

Idrovo, Alvaro J; Albavera-Hernández, Cidronio; Rodríguez-Hernández, Jorge Martín

2011-07-01

There are few social epidemiologic studies on chickenpox outbreaks, although previous findings suggested the important role of social determinants. This study describes the context of a large outbreak of chickenpox in the Cauca Valley region, Colombia (2003 to 2007), with an emphasis on macro-determinants. We explored the temporal trends in chickenpox incidence in 42 municipalities to identify the places with higher occurrences. We analyzed municipal characteristics (education quality, vaccination coverage, performance of health care services, violence-related immigration, and area size of planted sugar cane) through analyses based on set theory. Edwards-Venn diagrams were used to present the main findings. The results indicated that three municipalities had higher incidences and that poor quality education was the attribute most prone to a higher incidence. Potential use of set theory for exploratory outbreak analyses is discussed. It is a tool potentially useful to contrast units when only small sample sizes are available.

Timing, timing, timing: Fast decoding of object information from intracranial field potentials in human visual cortex

PubMed Central

Liu, Hesheng; Agam, Yigal; Madsen, Joseph R.; Kreiman, Gabriel

2010-01-01

Summary The difficulty of visual recognition stems from the need to achieve high selectivity while maintaining robustness to object transformations within hundreds of milliseconds. Theories of visual recognition differ in whether the neuronal circuits invoke recurrent feedback connections or not. The timing of neurophysiological responses in visual cortex plays a key role in distinguishing between bottom-up and top-down theories. Here we quantified at millisecond resolution the amount of visual information conveyed by intracranial field potentials from 912 electrodes in 11 human subjects. We could decode object category information from human visual cortex in single trials as early as 100 ms post-stimulus. Decoding performance was robust to depth rotation and scale changes. The results suggest that physiological activity in the temporal lobe can account for key properties of visual recognition. The fast decoding in single trials is compatible with feed-forward theories and provides strong constraints for computational models of human vision. PMID:19409272

Probing the electronic structure of liquid water with many-body perturbation theory

NASA Astrophysics Data System (ADS)

Pham, Tuan Anh; Zhang, Cui; Schwegler, Eric; Galli, Giulia

2014-03-01

We present a first-principles investigation of the electronic structure of liquid water based on many-body perturbation theory (MBPT), within the G0W0 approximation. The liquid quasiparticle band gap and the position of its valence band maximum and conduction band minimum with respect to vacuum were computed and it is shown that the use of MBPT is crucial to obtain results that are in good agreement with experiment. We found that the level of theory chosen to generate molecular dynamics trajectories may substantially affect the electronic structure of the liquid, in particular, the relative position of its band edges and redox potentials. Our results represent an essential step in establishing a predictive framework for computing the relative position of water redox potentials and the band edges of semiconductors and insulators. Work supported by DOE/BES (Grant No. DE-SC0008938). Work at LLNL was performed under Contract DE-AC52-07NA27344.

Domain-general contributions to social reasoning: theory of mind and deontic reasoning re-explored.

PubMed

McKinnon, Margaret C; Moscovitch, Morris

2007-02-01

Using older adults and dual-task interference, we examined performance on two social reasoning tasks: theory of mind (ToM) tasks and versions of the deontic selection task involving social contracts and hazardous conditions. In line with performance accounts of social reasoning, evidence from both aging and the dual-task method suggested that domain-general resources contribute to performance of these tasks. Specifically, older adults were impaired relative to younger adults on all types of social reasoning tasks tested; performance varied as a function of the demands these tasks placed on domain-general resources. Moreover, in younger adults, simultaneous performance of a working memory task interfered with younger adults' performance on both types of social reasoning tasks; here too, the magnitude of the interference effect varied with the processing demands of each task. Limits placed on social reasoning by executive functions contribute a great deal to performance, even in old age and in healthy younger adults under conditions of divided attention. The role of potentially non-modular and modular contributions to social reasoning is discussed.

Chemical Reactivity Theory Study of Advanced Glycation Endproduct Inhibitors.

PubMed

Frau, Juan; Glossman-Mitnik, Daniel

2017-02-02

Several compounds with the known ability to perform as inhibitors of advanced glycation endproducts (AGE) have been studied with Density Functional Theory (DFT) through the use of anumberofdensityfunctionalswhoseaccuracyhasbeentestedacrossabroadspectrumofdatabases in Chemistry and Physics. The chemical reactivity descriptors for these systems have been calculated through Conceptual DFT in an attempt to relate their intrinsic chemical reactivity with the ability to inhibit the action of glycating carbonyl compounds on amino acids and proteins. This knowledge could be useful in the design and development of new drugs which can be potential medicines for diabetes and Alzheimer's disease.

Bond order potential module for LAMMPS

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

2012-09-11

pair_bop is a module for performing energy calculations using the Bond Order Potential (BOP) for use in the parallel molecular dynamics code LAMMPS. The bop pair style computes BOP based upon quantum mechanical incorporating both sigma and pi bondings. By analytically deriving the BOP pair bop from quantum mechanical theory its transferability to different phases can approach that of quantum mechanical methods. This potential is extremely effective at modeling 111-V and II-VI compounds such as GaAs and CdTe. This potential is similar to the original BOP developed by Pettifor and later updated by Murdock et al. and Ward et al.

Examining Person--Environment Fit and Academic Major Satisfaction

ERIC Educational Resources Information Center

Milsom, Amy; Coughlin, Julie

2017-01-01

Decisions regarding college majors have the potential to affect a person's overall academic performance and long-term career success. With Holland's (1997) trait-and-factor theory serving as a foundation, the authors examined relationships between person-environment fit, college major satisfaction, and grade point average of undergraduate students…

A Motive of Rhetorics: Invention and Speech Acts.

ERIC Educational Resources Information Center

Schneider, Michael J.

While rhetorical theory has long been concerned with the epistemological foundations of rhetorical abilities, the full potential of the structuralist perspective is far from realized. The study of speech acts and inventive processes discloses the underlying logic of linguistic performance. A speech act is conceptualized in terms of the…

Strategies for Limiting Engineers' Potential Liability for Indoor Air Quality Problems.

PubMed

von Oppenfeld, Rolf R; Freeze, Mark E; Sabo, Sean M

1998-10-01

Engineers face indoor air quality (IAQ) issues at the design phase of building construction as well as during the investigation and mitigation of potential indoor air pollution problems during building operation. IAQ issues that can be identified are "building-related illnesses" that may include problems of volatile organic compounds (VOCs). IAQ issues that cannot be identified are termed "sick building syndrome." Frequently, microorganism-caused illnesses are difficult to confirm. Engineers who provide professional services that directly or indirectly impact IAQ face significant potential liability to clients and third parties when performing these duties. Potential theories supporting liability claims for IAQ problems against engineers include breach of contract and various common law tort theories such as negligence and negligent misrepresentation. Furthermore, an increasing number of federal, state, and local regulations affect IAQ issues and can directly increase the potential liability of engineers. A duty to disclose potential or actual air quality concerns to third parties may apply for engineers in given circumstances. Such a duty may arise from judicial precedent, the Model Guide for Professional Conduct for Engineers, or the Code of Ethics for Engineers. Practical strategies engineers can use to protect themselves from liability include regular training and continuing education in relevant regulatory, scientific, and case law developments; detailed documentation and recordkeeping practices; adequate insurance coverage; contractual indemnity clauses; contractual provisions limiting liability to the scope of work performed; and contractual provisions limiting the extent of liability for engineers' negligence. Furthermore, through the proper use of building materials and construction techniques, an engineer or other design professional can effectively limit the potential for IAQ liability.

Unified Aeroacoustics Analysis for High Speed Turboprop Aerodynamics and Noise. Volume 1; Development of Theory for Blade Loading, Wakes, and Noise

NASA Technical Reports Server (NTRS)

Hanson, D. B.

1991-01-01

A unified theory for the aerodynamics and noise of advanced turboprops are presented. Aerodynamic topics include calculation of performance, blade load distribution, and non-uniform wake flow fields. Blade loading can be steady or unsteady due to fixed distortion, counter-rotating wakes, or blade vibration. The aerodynamic theory is based on the pressure potential method and is therefore basically linear. However, nonlinear effects associated with finite axial induction and blade vortex flow are included via approximate methods. Acoustic topics include radiation of noise caused by blade thickness, steady loading (including vortex lift), and unsteady loading. Shielding of the fuselage by its boundary layer and the wing are treated in separate analyses that are compatible but not integrated with the aeroacoustic theory for rotating blades.

Meson properties in asymmetric matter

NASA Astrophysics Data System (ADS)

Mammarella, Andrea; Mannarelli, Massimo

2018-03-01

In this work we study dynamic and thermodynamic (at T = 0) properties of mesons in asymmetric matter in the framework of Chiral Perturbation Theory. We consider a system at vanishing temperature with nonzero isospin chemical potential and strangeness chemical potential; meson masses and mixing in the normal phase, the pion condensation phase and the kaon condensation phase are described. We find differences with previous works, but the results presented here are supported by both theory group analysis and by direct calculations. Some pion decay channels in the normal and the pion condensation phases are studied, finding a nonmonotonic behavior of the decay width as a function of µ I . Furthermore, pressure, density and equation of state of the system at T = 0 are studied, finding remarkable agreement with analogue studies performed by lattice calculations.

Theory and practice in the electrometric determination of pH in precipitation

NASA Astrophysics Data System (ADS)

Brennan, Carla Jo; Peden, Mark E.

Basic theory and laboratory investigations have been applied to the electrometric determination of pH in precipitation samples in an effort to improve the reliability of the results obtained from these low ionic strength samples. The theoretical problems inherent in the measurement of pH in rain have been examined using natural precipitation samples with varying ionic strengths and pH values. The importance of electrode design and construction has been stressed. The proper choice of electrode can minimize or eliminate problems arising from residual liquid junction potentials, streaming potentials and temperature differences. Reliable pH measurements can be made in precipitation samples using commercially available calibration buffers providing low ionic strength quality control solutions are routinely used to verify electrode and meter performance.

Facilitating progress in health behaviour theory development and modification: the reasoned action approach as a case study.

PubMed

Head, Katharine J; Noar, Seth M

2014-01-01

This paper explores the question: what are barriers to health behaviour theory development and modification, and what potential solutions can be proposed? Using the reasoned action approach (RAA) as a case study, four areas of theory development were examined: (1) the theoretical domain of a theory; (2) tension between generalisability and utility, (3) criteria for adding/removing variables in a theory, and (4) organisational tracking of theoretical developments and formal changes to theory. Based on a discussion of these four issues, recommendations for theory development are presented, including: (1) the theoretical domain for theories such as RAA should be clarified; (2) when there is tension between generalisability and utility, utility should be given preference given the applied nature of the health behaviour field; (3) variables should be formally removed/amended/added to a theory based on their performance across multiple studies and (4) organisations and researchers with a stake in particular health areas may be best suited for tracking the literature on behaviour-specific theories and making refinements to theory, based on a consensus approach. Overall, enhancing research in this area can provide important insights for more accurately understanding health behaviours and thus producing work that leads to more effective health behaviour change interventions.

The genetics of music accomplishment: evidence for gene-environment correlation and interaction.

PubMed

Hambrick, David Z; Tucker-Drob, Elliot M

2015-02-01

Theories of skilled performance that emphasize training history, such as K. Anders Ericsson and colleagues' deliberate-practice theory, have received a great deal of recent attention in both the scientific literature and the popular press. Twin studies, however, have demonstrated evidence for moderate-to-strong genetic influences on skilled performance. Focusing on musical accomplishment in a sample of over 800 pairs of twins, we found evidence for gene-environment correlation, in the form of a genetic effect on music practice. However, only about one quarter of the genetic effect on music accomplishment was explained by this genetic effect on music practice, suggesting that genetically influenced factors other than practice contribute to individual differences in music accomplishment. We also found evidence for gene-environment interaction, such that genetic effects on music accomplishment were most pronounced among those engaging in music practice, suggesting that genetic potentials for skilled performance are most fully expressed and fostered by practice.

Fundamental Neutron Physics: Theory and Analysis

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

Gudkov, Vladimir

The goal of the proposal was to study the possibility of searching for manifestations of new physics beyond the Standard model in fundamental neutron physics experiments. This involves detailed theoretical analyses of parity- and time reversal invariance-violating processes in neutron-induced reactions, properties of neutron β-decay, and the precise description of properties of neutron interactions with nuclei. To describe neutron-nuclear interactions, we use both the effective field theory approach and the theory of nuclear reaction with phenomenological nucleon potentials for the systematic description of parity- and time reversal-violating effects in the consistent way. A major emphasis of our research during themore » funding period has been the study of parity violation (PV) and time reversal invariance violation (TRIV) in few-body systems. We studied PV effects in non-elastic processes in three-nucleon system using both ”DDH-like” and effective field theory (EFT) approaches. The wave functions were obtained by solving three-body Faddeev equations in configuration space for a number of realistic strong potentials. The observed model dependence for the DDH approach indicates intrinsic difficulty in the description of nuclear PV effects, and it could be the reason for the observed discrepancies in the nuclear PV data analysis. It shows that the DDH approach could be a reasonable approach for analysis of PV effects only if exactly the same strong and weak potentials are used in calculating all PV observables in all nuclei. However, the existing calculations of nuclear PV effects were performed using different potentials; therefore, strictly speaking, one cannot compare the existing results of these calculations among themselves.« less

Performance Characterization, Development, and Application of Artificial Potential Function Guidance Methods

DTIC Science & Technology

2014-03-01

to determine if a system is stabilizable with feedback. 12 that asymptotic stability is guaranteed by Lyapunov theory. The advantage of this method are...discretized dynamics are a sufficient representation of the continuous system . Given these assumptions, the optimal control problem for minimum transit time is...tion (APF) guidance performance when applied to systems with limited control au- thority in a dynamic environment and then to use the findings to

Why does offspring size affect performance? Integrating metabolic scaling with life-history theory

PubMed Central

Pettersen, Amanda K.; White, Craig R.; Marshall, Dustin J.

2015-01-01

Within species, larger offspring typically outperform smaller offspring. While the relationship between offspring size and performance is ubiquitous, the cause of this relationship remains elusive. By linking metabolic and life-history theory, we provide a general explanation for why larger offspring perform better than smaller offspring. Using high-throughput respirometry arrays, we link metabolic rate to offspring size in two species of marine bryozoan. We found that metabolism scales allometrically with offspring size in both species: while larger offspring use absolutely more energy than smaller offspring, larger offspring use proportionally less of their maternally derived energy throughout the dependent, non-feeding phase. The increased metabolic efficiency of larger offspring while dependent on maternal investment may explain offspring size effects—larger offspring reach nutritional independence (feed for themselves) with a higher proportion of energy relative to structure than smaller offspring. These findings offer a potentially universal explanation for why larger offspring tend to perform better than smaller offspring but studies on other taxa are needed. PMID:26559952

Optical communication with two-photon coherent stages. I - Quantum-state propagation and quantum-noise reduction

NASA Technical Reports Server (NTRS)

Yuen, H. P.; Shapiro, J. H.

1978-01-01

To determine the ultimate performance limitations imposed by quantum effects, it is also essential to consider optimum quantum-state generation. Certain 'generalized' coherent states of the radiation field possess novel quantum noise characteristics that offer the potential for greatly improved optical communications. These states have been called two-photon coherent states because they can be generated, in principle, by stimulated two-photon processes. The use of two-photon coherent state (TCS) radiation in free-space optical communications is considered. A simple theory of quantum state propagation is developed. The theory provides the basis for representing the free-space channel in a quantum-mechanical form convenient for communication analysis. The new theory is applied to TCS radiation.

Theory of mind may be contagious, but you don't catch it from your twin.

PubMed

Wright Cassidy, Kimberly; Shaw Fineberg, Deborah; Brown, Kimberly; Perkins, Alexis

2005-01-01

The theory-of-mind abilities of twins, children with nontwin siblings, and only children were compared to investigate further the link between number and type of siblings and theory-of-mind abilities. Three- to 5-year-old children with nontwin siblings outperformed both only children and twins with no other siblings, twins who also had other siblings outperformed twins who did not, and children with at least 1 opposite-sex sibling outperformed children with only same-sex siblings. Twins performed significantly better when asked about the false beliefs of their twins than they did when asked about the false beliefs of their friends. Results are discussed in terms of potential mechanisms that may account for the twin and sibling effects.

Comparison of non-ideal solution theories for multi-solute solutions in cryobiology and tabulation of required coefficients.

PubMed

Zielinski, Michal W; McGann, Locksley E; Nychka, John A; Elliott, Janet A W

2014-10-01

Thermodynamic solution theories allow the prediction of chemical potentials in solutions of known composition. In cryobiology, such models are a critical component of many mathematical models that are used to simulate the biophysical processes occurring in cells and tissues during cryopreservation. A number of solution theories, both thermodynamically ideal and non-ideal, have been proposed for use with cryobiological solutions. In this work, we have evaluated two non-ideal solution theories for predicting water chemical potential (i.e. osmolality) in multi-solute solutions relevant to cryobiology: the Elliott et al. form of the multi-solute osmotic virial equation, and the Kleinhans and Mazur freezing point summation model. These two solution theories require fitting to only single-solute data, although they can make predictions in multi-solute solutions. The predictions of these non-ideal solution theories were compared to predictions made using ideal dilute assumptions and to available literature multi-solute experimental osmometric data. A single, consistent set of literature single-solute solution data was used to fit for the required solute-specific coefficients for each of the non-ideal models. Our results indicate that the two non-ideal solution theories have similar overall performance, and both give more accurate predictions than ideal models. These results can be used to select between the non-ideal models for a specific multi-solute solution, and the updated coefficients provided in this work can be used to make the desired predictions. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Strategic issues in performance appraisal: theory and practice.

PubMed

Fombrun, C J; Laud, R L

1983-01-01

Performance appraisal systems have tremendous strategic potential for governing employee behavior and thus corporate direction through their links to selection, training and career planning, and reward systems. Authors Charles J. Fombrun, assistant professor of management at the University of Pennsylvania's Wharton School, and Robert P. Laud, senior vice-president of Drake Beam Morin, Inc., surveyed appraisal systems of Fortune 1300 corporations to find out how well companies are realizing this potential. Among their conclusions: (1) In most organizations, the typical performance appraisal system is focused on short-term goals. Strengthening the linkage between the appraisal system and the long-term implications of strategic planning could improve organizational effectiveness in the future. (2) The performance appraisal system's most prevalent use is as a feedback mechanism rather than as a management tool. Thus, the authors conclude, the role of the performance appraisal system as a strategic organizational tool is largely unappreciated by U.S. organizations.

Bridging the gap between neurocognitive processing theory and performance validity assessment among the cognitively impaired: a review and methodological approach.

PubMed

Leighton, Angela; Weinborn, Michael; Maybery, Murray

2014-10-01

Bigler (2012) and Larrabee (2012) recently addressed the state of the science surrounding performance validity tests (PVTs) in a dialogue highlighting evidence for the valid and increased use of PVTs, but also for unresolved problems. Specifically, Bigler criticized the lack of guidance from neurocognitive processing theory in the PVT literature. For example, individual PVTs have applied the simultaneous forced-choice methodology using a variety of test characteristics (e.g., word vs. picture stimuli) with known neurocognitive processing implications (e.g., the "picture superiority effect"). However, the influence of such variations on classification accuracy has been inadequately evaluated, particularly among cognitively impaired individuals. The current review places the PVT literature in the context of neurocognitive processing theory, and identifies potential methodological factors to account for the significant variability we identified in classification accuracy across current PVTs. We subsequently evaluated the utility of a well-known cognitive manipulation to provide a Clinical Analogue Methodology (CAM), that is, to alter the PVT performance of healthy individuals to be similar to that of a cognitively impaired group. Initial support was found, suggesting the CAM may be useful alongside other approaches (analogue malingering methodology) for the systematic evaluation of PVTs, particularly the influence of specific neurocognitive processing components on performance.

Autobiographical memory in adults with autism spectrum disorder: the role of depressed mood, rumination, working memory and theory of mind.

PubMed

Crane, Laura; Goddard, Lorna; Pring, Linda

2013-03-01

Autobiographical memory difficulties have been widely reported in adults with autism spectrum disorder (ASD). The aim of the current study was to explore the potential correlates of autobiographical memory performance (including depressed mood, rumination, working memory and theory of mind) in adults with ASD, relative to a group of typical adults matched for age, gender and IQ. Results demonstrated that the adults with ASD reported higher levels of depressed mood and rumination than the typical adults, and also received lower scores on measures of theory of mind and working memory. Correlational analysis suggested that theory of mind and working memory were associated with autobiographical memory performance in the adults with ASD, but no significant relationships were observed between autobiographical memory, depressed mood and rumination in this group. To explore these patterns further, two cases of adults with a dual diagnosis of ASD and depression are discussed. These participants present a profile in line with the idea that depressed mood and rumination do not have the same influence on autobiographical memory in adults with ASD as they do in typical adults.

Vibrational spectroscopy and density functional theory analysis of 3-O-caffeoylquinic acid

NASA Astrophysics Data System (ADS)

Mishra, Soni; Tandon, Poonam; Eravuchira, Pinkie J.; El-Abassy, Rasha M.; Materny, Arnulf

2013-03-01

Density functional theory (DFT) calculations are being performed to investigate the geometric, vibrational, and electronic properties of the chlorogenic acid isomer 3-CQA (1R,3R,4S,5R)-3-{[(2E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-1,4,5-trihydroxycyclohexanecarboxylic acid), a major phenolic compound in coffee. DFT calculations with the 6-311G(d,p) basis set produce very good results. The electrostatic potential mapped onto an isodensity surface has been obtained. A natural bond orbital analysis (NBO) has been performed in order to study intramolecular bonding, interactions among bonds, and delocalization of unpaired electrons. HOMO-LUMO studies give insights into the interaction of the molecule with other species. The calculated HOMO and LUMO energies indicate that a charge transfer occurs within the molecule.

Model, Framework, and Platform of Health Persuasive Social Network

ERIC Educational Resources Information Center

Al Ayubi, Soleh Udin

2013-01-01

Persuasive technology (PT) has the potential to support individuals to perform self-management and social support as a part of health behavior change. This has led a few researchers in the intersection of the areas of health behavior change and software engineering to apply behavior change and persuasion theories to software development practices,…

A preliminary discussion of gravitational physics experiments for the Spacelab era

NASA Technical Reports Server (NTRS)

Decher, R.; Winkler, C. G.

1976-01-01

An overview of past, present, and proposed future experiments in gravitational physics is given. These experiments are concerned with the measurement of relativistic gravity effects to test theories of gravitation. Certain experiments which could be performed on shuttle and Spacelab missions and the potential of Spacelab for gravitation physics research are discussed.

Maximizing Potential: A School-Based Conception of Psychosocial Development

ERIC Educational Resources Information Center

Cross, Tracy L.; Cross, Jennifer Riedl

2017-01-01

Optimal talent development can only occur when high ability students are willing to take opportunities for growth in a domain and are able to persist when presented with challenges that accompany performance or production at the highest levels. This paper proposes the use of Erikson's theory of psychosocial development to provide a framework…

Neural Correlates of Children's Theory of Mind Development

ERIC Educational Resources Information Center

Liu, David; Sabbagh, Mark A.; Gehring, William J.; Wellman, Henry M.

2009-01-01

Young children show significant changes in their mental-state understanding as marked by their performance on false-belief tasks. This study provides evidence for activity in the prefrontal cortex associated with the development of this ability. Event-related brain potentials (ERPs) were recorded as adults (N = 24) and 4-, 5-, and 6-year-old…

Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory.

PubMed

Inkaya, Ersin; Dinçer, Muharrem; Sahan, Emine; Yıldırım, Ismail

2013-10-01

In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, (1)H NMR, (13)C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z=2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis, spectroscopic and structural characterization of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine with theoretical calculations using density functional theory

NASA Astrophysics Data System (ADS)

İnkaya, Ersin; Dinçer, Muharrem; Şahan, Emine; Yıldırım, İsmail

2013-10-01

In this paper, we will report a combined experimental and theoretical investigation of the molecular structure and spectroscopic parameters (FT-IR, 1H NMR, 13C NMR) of 5-benzoyl-4-phenyl-2-methylthio-1H-pyrimidine. The compound crystallizes in the triclinic space group P-1 with Z = 2. The molecular geometry was also optimized using density functional theory (DFT/B3LYP) method with the 6-311G(d,p) and 6-311++G(d,p) basis sets in ground state and compared with the experimental data. All the assignments of the theoretical frequencies were performed by potential energy distributions using VEDA 4 program. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP). Also, non-linear optical properties of the title compound were performed at B3LYP/6-311++G(d,p) level. The theoretical results showed an excellent agreement with the experimental values.

Theory of mind and verbal working memory deficits in parents of autistic children.

PubMed

Gokcen, Sezen; Bora, Emre; Erermis, Serpil; Kesikci, Hande; Aydin, Cahide

2009-03-31

The objective of this study was to investigate the potential values of executive function and social cognition deficits as endophenotypes of autism. While theory of mind (ToM) is generally accepted as a unitary concept, some have suggested that ToM may be separated into two components (mental state reasoning and decoding). In this study, both aspects of ToM and verbal working memory abilities were investigated with relatively demanding tasks. The authors used a neurocognitive battery to compare the executive function and social cognition skills of 76 parents of autistic probands with 41 parents of healthy children. Both groups were matched for IQ, age and gender. Index parents had verbal working memory deficits. They had also low performance on a mental state reasoning task. Index parents had difficulties in reasoning about others' emotions. In contrast to findings in the control group, low performance of mental state reasoning ability was not associated with working memory deficit in index parents. Social cognition and working memory impairments may represent potential endophenotypes, related to an underlying vulnerability for autistic spectrum disorders.

The processing of unexpected positive response outcomes in the mediofrontal cortex.

PubMed

Ferdinand, Nicola K; Mecklinger, Axel; Kray, Jutta; Gehring, William J

2012-08-29

The human mediofrontal cortex, especially the anterior cingulate cortex, is commonly assumed to contribute to higher cognitive functions like performance monitoring. How exactly this is achieved is currently the subject of lively debate but there is evidence that an event's valence and its expectancy play important roles. One prominent theory, the reinforcement learning theory by Holroyd and colleagues (2002, 2008), assigns a special role to feedback valence, while the prediction of response-outcome (PRO) model by Alexander and Brown (2010, 2011) claims that the mediofrontal cortex is sensitive to unexpected events regardless of their valence. However, paradigms examining this issue have included confounds that fail to separate valence and expectancy. In the present study, we tested the two competing theories of performance monitoring by using an experimental task that separates valence and unexpectedness of performance feedback. The feedback-related negativity of the event-related potential, which is commonly assumed to be a reflection of mediofrontal cortex activity, was elicited not only by unexpected negative feedback, but also by unexpected positive feedback. This implies that the mediofrontal cortex is sensitive to the unexpectedness of events in general rather than their valence and by this supports the PRO model.

Comparison of the Melting Temperatures of Classical and Quantum Water Potential Models

NASA Astrophysics Data System (ADS)

Du, Sen; Yoo, Soohaeng; Li, Jinjin

2017-08-01

As theoretical approaches and technical methods improve over time, the field of computer simulations for water has greatly progressed. Water potential models become much more complex when additional interactions and advanced theories are considered. Macroscopic properties of water predicted by computer simulations using water potential models are expected to be consistent with experimental outcomes. As such, discrepancies between computer simulations and experiments could be a criterion to comment on the performances of various water potential models. Notably, water can occur not only as liquid phases but also as solid and vapor phases. Therefore, the melting temperature related to the solid and liquid phase equilibrium is an effective parameter to judge the performances of different water potential models. As a mini review, our purpose is to introduce some water models developed in recent years and the melting temperatures obtained through simulations with such models. Moreover, some explanations referred to in the literature are described for the additional evaluation of the water potential models.

Monocrystalline solar cells performance coated by silver nanoparticles: Effect of NPs sizes from point of view Mie theory

NASA Astrophysics Data System (ADS)

Elnoby, Rasha M.; Mourad, M. Hussein; Elnaby, Salah L. Hassab; Abou Kana, Maram T. H.

2018-05-01

Solar based cells coated by nanoparticles (NPs) acknowledge potential utilizing as a part of photovoltaic innovation. The acquired silicon solar cells (Si-SCs) coated with different sizes of silver nanoparticles (Ag NPs) as well as uncoated were fabricated in our lab. The sizes and optical properties of prepared NPs were characterized by spectroscopic techniques and Mie theory respectively. The reflectivity of Si-SCs showed reduction of this property as the size of NPs increased. Electrical properties as open circuit current, fill factor and output power density were assessed and discussed depending on point of view of Mie theory for the optical properties of NPs. Also, photostabilities of SCs were assessed using diode laser of wavelength 450 nm and power 300 mW. Coated SCs with the largest Ag NPs size showed the highest Photostability due to its highest scattering efficiency according to Mie theory concept.

Performing Desistance: How Might Theories of Desistance From Crime Help Us Understand the Possibilities of Prison Theatre?

PubMed

Davey, Linda; Day, Andrew; Balfour, Michael

2015-07-01

Despite the ubiquity of theatre projects in prisons there has been little (published) discussion of the application of theatre to the theories of criminology or rehabilitation of offenders, and scant examination of the potential for criminological theories to inform theatre practice in criminal justice settings. This article seeks to address this deficit and argues that positioning prison theatre within the discipline of positive criminology, specifically contemporary theories of desistance from crime, provides a theoretical framework for understanding the contribution that prison theatre might be making in the correctional setting. Through a review of related literature, the article explores how prison theatre may be motivating offenders toward the construction of a more adaptive narrative identity and toward the acquisition of capabilities that might usefully assist them in the process of desisting from crime. © The Author(s) 2014.

Parallel software for lattice N = 4 supersymmetric Yang-Mills theory

NASA Astrophysics Data System (ADS)

Schaich, David; DeGrand, Thomas

2015-05-01

We present new parallel software, SUSY LATTICE, for lattice studies of four-dimensional N = 4 supersymmetric Yang-Mills theory with gauge group SU(N). The lattice action is constructed to exactly preserve a single supersymmetry charge at non-zero lattice spacing, up to additional potential terms included to stabilize numerical simulations. The software evolved from the MILC code for lattice QCD, and retains a similar large-scale framework despite the different target theory. Many routines are adapted from an existing serial code (Catterall and Joseph, 2012), which SUSY LATTICE supersedes. This paper provides an overview of the new parallel software, summarizing the lattice system, describing the applications that are currently provided and explaining their basic workflow for non-experts in lattice gauge theory. We discuss the parallel performance of the code, and highlight some notable aspects of the documentation for those interested in contributing to its future development.

Nuclear shielding constants by density functional theory with gauge including atomic orbitals

NASA Astrophysics Data System (ADS)

Helgaker, Trygve; Wilson, Philip J.; Amos, Roger D.; Handy, Nicholas C.

2000-08-01

Recently, we introduced a new density-functional theory (DFT) approach for the calculation of NMR shielding constants. First, a hybrid DFT calculation (using 5% exact exchange) is performed on the molecule to determine Kohn-Sham orbitals and their energies; second, the constants are determined as in nonhybrid DFT theory, that is, the paramagnetic contribution to the constants is calculated from a noniterative, uncoupled sum-over-states expression. The initial results suggested that this semiempirical DFT approach gives shielding constants in good agreement with the best ab initio and experimental data; in this paper, we further validate this procedure, using London orbitals in the theory, having implemented DFT into the ab initio code DALTON. Calculations on a number of small and medium-sized molecules confirm that our approach produces shieldings in excellent agreement with experiment and the best ab initio results available, demonstrating its potential for the study of shielding constants of large systems.

Robust determination of the chemical potential in the pole expansion and selected inversion method for solving Kohn-Sham density functional theory

NASA Astrophysics Data System (ADS)

Jia, Weile; Lin, Lin

2017-10-01

Fermi operator expansion (FOE) methods are powerful alternatives to diagonalization type methods for solving Kohn-Sham density functional theory (KSDFT). One example is the pole expansion and selected inversion (PEXSI) method, which approximates the Fermi operator by rational matrix functions and reduces the computational complexity to at most quadratic scaling for solving KSDFT. Unlike diagonalization type methods, the chemical potential often cannot be directly read off from the result of a single step of evaluation of the Fermi operator. Hence multiple evaluations are needed to be sequentially performed to compute the chemical potential to ensure the correct number of electrons within a given tolerance. This hinders the performance of FOE methods in practice. In this paper, we develop an efficient and robust strategy to determine the chemical potential in the context of the PEXSI method. The main idea of the new method is not to find the exact chemical potential at each self-consistent-field (SCF) iteration but to dynamically and rigorously update the upper and lower bounds for the true chemical potential, so that the chemical potential reaches its convergence along the SCF iteration. Instead of evaluating the Fermi operator for multiple times sequentially, our method uses a two-level strategy that evaluates the Fermi operators in parallel. In the regime of full parallelization, the wall clock time of each SCF iteration is always close to the time for one single evaluation of the Fermi operator, even when the initial guess is far away from the converged solution. We demonstrate the effectiveness of the new method using examples with metallic and insulating characters, as well as results from ab initio molecular dynamics.

Robust determination of the chemical potential in the pole expansion and selected inversion method for solving Kohn-Sham density functional theory.

PubMed

Jia, Weile; Lin, Lin

2017-10-14

Fermi operator expansion (FOE) methods are powerful alternatives to diagonalization type methods for solving Kohn-Sham density functional theory (KSDFT). One example is the pole expansion and selected inversion (PEXSI) method, which approximates the Fermi operator by rational matrix functions and reduces the computational complexity to at most quadratic scaling for solving KSDFT. Unlike diagonalization type methods, the chemical potential often cannot be directly read off from the result of a single step of evaluation of the Fermi operator. Hence multiple evaluations are needed to be sequentially performed to compute the chemical potential to ensure the correct number of electrons within a given tolerance. This hinders the performance of FOE methods in practice. In this paper, we develop an efficient and robust strategy to determine the chemical potential in the context of the PEXSI method. The main idea of the new method is not to find the exact chemical potential at each self-consistent-field (SCF) iteration but to dynamically and rigorously update the upper and lower bounds for the true chemical potential, so that the chemical potential reaches its convergence along the SCF iteration. Instead of evaluating the Fermi operator for multiple times sequentially, our method uses a two-level strategy that evaluates the Fermi operators in parallel. In the regime of full parallelization, the wall clock time of each SCF iteration is always close to the time for one single evaluation of the Fermi operator, even when the initial guess is far away from the converged solution. We demonstrate the effectiveness of the new method using examples with metallic and insulating characters, as well as results from ab initio molecular dynamics.

Direct measurements of forces between different charged colloidal particles and their prediction by the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO)

NASA Astrophysics Data System (ADS)

Ruiz-Cabello, F. Javier Montes; Maroni, Plinio; Borkovec, Michal

2013-06-01

Force measurements between three types of latex particles of diameters down to 1 μm with sulfate and carboxyl surface functionalities were carried out with the multi-particle colloidal probe technique. The experiments were performed in monovalent electrolyte up to concentrations of about 5 mM. The force profiles could be quantified with the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) by invoking non-retarded van der Waals forces and the Poisson-Boltzmann description of double layer forces within the constant regulation approximation. The forces measured in the symmetric systems were used to extract particle and surface properties, namely, the Hamaker constant, surface potentials, and regulation parameters. The regulation parameter is found to be independent of solution composition. With these values at hand, the DLVO theory is capable to accurately predict the measured forces in the asymmetric systems down to distances of 2-3 nm without adjustable parameters. This success indicates that DLVO theory is highly reliable to quantify interaction forces in such systems. However, charge regulation effects are found to be important, and they must be considered to obtain correct description of the forces. The use of the classical constant charge or constant potential boundary conditions may lead to erroneous results. To make reliable predictions of the force profiles, the surface potentials must be extracted from direct force measurements too. For highly charged surfaces, the commonly used electrophoresis techniques are found to yield incorrect estimates of this quantity.

Direct measurements of forces between different charged colloidal particles and their prediction by the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO).

PubMed

Montes Ruiz-Cabello, F Javier; Maroni, Plinio; Borkovec, Michal

2013-06-21

Force measurements between three types of latex particles of diameters down to 1 μm with sulfate and carboxyl surface functionalities were carried out with the multi-particle colloidal probe technique. The experiments were performed in monovalent electrolyte up to concentrations of about 5 mM. The force profiles could be quantified with the theory of Derjaguin, Landau, Verwey, and Overbeek (DLVO) by invoking non-retarded van der Waals forces and the Poisson-Boltzmann description of double layer forces within the constant regulation approximation. The forces measured in the symmetric systems were used to extract particle and surface properties, namely, the Hamaker constant, surface potentials, and regulation parameters. The regulation parameter is found to be independent of solution composition. With these values at hand, the DLVO theory is capable to accurately predict the measured forces in the asymmetric systems down to distances of 2-3 nm without adjustable parameters. This success indicates that DLVO theory is highly reliable to quantify interaction forces in such systems. However, charge regulation effects are found to be important, and they must be considered to obtain correct description of the forces. The use of the classical constant charge or constant potential boundary conditions may lead to erroneous results. To make reliable predictions of the force profiles, the surface potentials must be extracted from direct force measurements too. For highly charged surfaces, the commonly used electrophoresis techniques are found to yield incorrect estimates of this quantity.

Factors influencing the provision of oral hygiene care following stroke: an application of the Theory of Planned Behaviour.

PubMed

Ab Malik, Normaliza; Mohamad Yatim, Saari; Lam, Otto L T; Jin, Lijian; McGrath, Colman

2018-04-01

This study aimed to examine "intention to" and "performance of" oral hygiene care to stroke patients using the Theory of Planned Behavior. A large scale survey of 13 centers in Malaysia was conducted involving 806 nurses in relation to oral hygiene care intentions and practices. In addition, information on personal and environmental factors was collected. The response rate was 95.6% (778/806). The domains of the Theory of Planned Behavior were significantly associated with general intention to perform oral hygiene care: attitudes (β = 0.21, p < 0.001), subjective norms (β = 0.38, p < 0.001), perceived behavior control (β = 0.04, p < 0.001); after controlling for personal and environmental factors. Approximately two-thirds (63.4%, 493) reported the performance of some form of oral hygiene care for patients. This behavior was associated with general intention scores (OR =1.13, 95%CI =1.05-1.22, p <0.01), controlling for other factors. Knowledge scores, training, access to oral hygiene guidelines and kits, as well as working ward type were identified as key factors associated with intention and practice of oral hygiene care. The Theory of Planned Behavior provides understanding of "intention to" and "performance of" oral hygiene care to stroke patients. Several provider and environmental factors were also associated with intentions and practices. This has implications for understanding and improving the implementation of oral hygiene care in stroke rehabilitation. Implications for Rehabilitation Oral hygiene care is crucial for stroke patients as it can prevent oral health problems and potentially life threatening events (such as aspiration pneumonia). Despite oral hygiene care being relative simple to perform, it is often neglected during stroke rehabilitation. A large-scale national survey was conducted to understand "intentions to" and "performance of" oral hygiene care to stroke patients using the Theory of Planned Behavior social cognition model. These study findings may have implications and use in promoting oral hygiene care to stroke patients:i) by understanding the pathways and influences to perform oral hygiene care.ii) to conduct health promotion and health education based on behavioral models such as Theory of Planned Behavior.

Kinetic study on the H + SiH4 abstraction reaction using an ab initio potential energy surface.

PubMed

Cao, Jianwei; Zhang, Zhijun; Zhang, Chunfang; Bian, Wensheng; Guo, Yin

2011-01-14

Variational transition state theory calculations with the correction of multidimensional tunneling are performed on a 12-dimensional ab initio potential energy surface for the H + SiH(4) abstraction reaction. The surface is constructed using a dual-level strategy. For the temperature range 200-1600 K, thermal rate constants are calculated and kinetic isotope effects for various isotopic species of the title reaction are investigated. The results are in very good agreement with available experimental data.

Conductivity of graphene in the framework of Dirac model: Interplay between nonzero mass gap and chemical potential

NASA Astrophysics Data System (ADS)

Klimchitskaya, G. L.; Mostepanenko, V. M.; Petrov, V. M.

2017-12-01

The complete theory of electrical conductivity of graphene at arbitrary temperature is developed with taking into account mass-gap parameter and chemical potential. Both the in-plane and out-of-plane conductivities of graphene are expressed via the components of the polarization tensor in (2+1)-dimensional space-time analytically continued to the real frequency axis. Simple analytic expressions for both the real and imaginary parts of the conductivity of graphene are obtained at zero and nonzero temperature. They demonstrate an interesting interplay depending on the values of mass gap and chemical potential. In the local limit, several results obtained earlier using various approximate and phenomenological approaches are reproduced, refined, and generalized. The numerical computations of both the real and imaginary parts of the conductivity of graphene are performed to illustrate the obtained results. The analytic expressions for the conductivity of graphene obtained in this paper can serve as a guide in the comparison between different theoretical approaches and between experiment and theory.

An experimental and theoretical method for determination of standard electrode potential for the redox couple diphenyl sulfone/diphenyl sulfide

NASA Astrophysics Data System (ADS)

Song, Y. Z.; Wei, K. X.; Lv, J. S.

2013-12-01

DFT calculations were performed for diphenyl sulfide and diphenyl sulfone. The electrochemistry of diphenyl sulfide on the gold electrode was investigated by cyclic voltammety and the results show that standard electrode potential for redox couple diphenyl sulfone/diphenyl sulfide is 1.058 V, which is consistent with that of 1.057 calculated at B3LYP/6-31++G( d, p)-IEFPCM level. The front orbit theory and Mulliken charges of molecular explain well on the oxidation of diphenyl sulfide in oxidative desulfurization. According to equilibrium theory the experimental equilibrium constant in the oxidative desulfurization of H2O2, is 1.17 × 1048, which is consistent with the theoretical equilibrium constant is 2.18 × 1048 at B3LYP/6-31++G( d, p)-IEFPCM level.

In your eyes: does theory of mind predict impaired life functioning in bipolar disorder?

PubMed

Purcell, Amanda L; Phillips, Mary; Gruber, June

2013-12-01

Deficits in emotion perception and social functioning are strongly implicated in bipolar disorder (BD). Examining theory of mind (ToM) may provide one potential mechanism to explain observed socio-emotional impairments in this disorder. The present study prospectively investigated the relationship between theory of mind performance and life functioning in individuals diagnosed with BD compared to unipolar depression and healthy control groups. Theory of mind (ToM) performance was examined in 26 individuals with remitted bipolar I disorder (BD), 29 individuals with remitted unipolar depression (UD), and 28 healthy controls (CTL) using a well-validated advanced theory of mind task. Accuracy and response latency scores were calculated from the task. Life functioning was measured during a 12 month follow-up session. No group differences for ToM accuracy emerged. However, the BD group exhibited significantly shorter response times than the UD and CTL groups. Importantly, quicker response times in the BD group predicted greater life functioning impairment at a 12-month follow-up, even after controlling for baseline symptoms. The stimuli were static representations of emotional states and do not allow for evaluating the appropriateness of context during emotional communication; due to sample size, neither specific comorbidities nor medication effects were analyzed for the BD and UD groups; preliminary status of theory of mind as a construct. Results suggest that quickened socio-emotional decision making may represent a risk factor for future functional impairment in BD. Copyright © 2013 Elsevier B.V. All rights reserved.

Molecular dynamics studies of electron-ion temperature equilibration in hydrogen plasmas within the coupled-mode regime

DOE PAGES

Benedict, Lorin X.; Surh, Michael P.; Stanton, Liam G.; ...

2017-04-10

Here, we use classical molecular dynamics (MD) to study electron-ion temperature equilibration in two-component plasmas in regimes for which the presence of coupled collective modes has been predicted to substantively reduce the equilibration rate. Guided by previous kinetic theory work, we examine hydrogen plasmas at a density of n = 10 26cm –3, T i = 10 5K, and 10 7 K < Te < 10 9K. The nonequilibrium classical MD simulations are performed with interparticle interactions modeled by quantum statistical potentials (QSPs). Our MD results indicate (i) a large effect from time-varying potential energy, which we quantify by appealingmore » to an adiabatic two-temperature equation of state, and (ii) a notable deviation in the energy equilibration rate when compared to calculations from classical Lenard-Balescu theory including the QSPs. In particular, it is shown that the energy equilibration rates from MD are more similar to those of the theory when coupled modes are neglected. We suggest possible reasons for this surprising result and propose directions of further research along these lines.« less

Systematics of Rydberg Series of Diatomic Molecules and Correlation Diagrams

NASA Astrophysics Data System (ADS)

Lee, Chun-Woo

2015-06-01

Rydberg states are studied for H2, Li2, HeH, LiH and BeH using the multi-reference configuration interaction (MRCI) method. The systematics and regularities of the physical properties such as potential energies curves (PECs), quantum defect curves, permanent dipole moment and transition dipole moment curves of the Rydberg series are studied. They are explained using united atom perturbation theory by Bingel and Byers-Brown, Fermi model, Stark theory, and Mulliken's theory. Interesting mirror relationships of the dipole moments are observed between l-mixed Rydberg series, indicating that the members of the l-mixed Rydberg series have dipole moments with opposite directions, which are related to the reversal of the polarity of a dipole moment at the avoided crossing points. The assignment of highly excited states is difficult because of the usual absence of the knowledge on the behaviors of potential energy curves at small internuclear separation whereby the correlation between the united atom limit and separated atoms limit cannot be given. All electron MRCI calculations of PECs are performed to obtain the correlation diagrams between Rydberg orbitals at the united-atom and separated atoms limits.

The Importance of Electron Correlation on Stacking Interaction of Adenine-Thymine Base-Pair Step in B-DNA: A Quantum Monte Carlo Study.

PubMed

Hongo, Kenta; Cuong, Nguyen Thanh; Maezono, Ryo

2013-02-12

We report fixed-node diffusion Monte Carlo (DMC) calculations of stacking interaction energy between two adenine(A)-thymine(T) base pairs in B-DNA (AA:TT), for which reference data are available, obtained from a complete basis set estimate of CCSD(T) (coupled-cluster with singles, doubles, and perturbative triples). We consider four sets of nodal surfaces obtained from self-consistent field calculations and examine how the different nodal surfaces affect the DMC potential energy curves of the AA:TT molecule and the resulting stacking energies. We find that the DMC potential energy curves using the different nodes look similar to each other as a whole. We also benchmark the performance of various quantum chemistry methods, including Hartree-Fock (HF) theory, second-order Møller-Plesset perturbation theory (MP2), and density functional theory (DFT). The DMC and recently developed DFT results of the stacking energy reasonably agree with the reference, while the HF, MP2, and conventional DFT methods give unsatisfactory results.

Dirac and non-Dirac conditions in the two-potential theory of magnetic charge

NASA Astrophysics Data System (ADS)

Scott, John; Evans, Timothy J.; Singleton, Douglas; Dzhunushaliev, Vladimir; Folomeev, Vladimir

2018-05-01

We investigate the Cabbibo-Ferrari, two-potential approach to magnetic charge coupled to two different complex scalar fields, Φ _1 and Φ _2, each having different electric and magnetic charges. The scalar field, Φ _1, is assumed to have a spontaneous symmetry breaking self-interaction potential which gives a mass to the "magnetic" gauge potential and "magnetic" photon, while the other "electric" gauge potential and "electric" photon remain massless. The magnetic photon is hidden until one reaches energies of the order of the magnetic photon rest mass. The second scalar field, Φ _2, is required in order to make the theory non-trivial. With only one field one can always use a duality rotation to rotate away either the electric or magnetic charge, and thus decouple either the associated electric or magnetic photon. In analyzing this system of two scalar fields in the Cabbibo-Ferrari approach we perform several duality and gauge transformations, which require introducing non-Dirac conditions on the initial electric and magnetic charges. We also find that due to the symmetry breaking the usual Dirac condition is altered to include the mass of the magnetic photon. We discuss the implications of these various conditions on the charges.

Factors influencing variation in physician adenoma detection rates: a theory-based approach for performance improvement.

PubMed

Atkins, Louise; Hunkeler, Enid M; Jensen, Christopher D; Michie, Susan; Lee, Jeffrey K; Doubeni, Chyke A; Zauber, Ann G; Levin, Theodore R; Quinn, Virginia P; Corley, Douglas A

2016-03-01

Interventions to improve physician adenoma detection rates for colonoscopy have generally not been successful, and there are little data on the factors contributing to variation that may be appropriate targets for intervention. We sought to identify factors that may influence variation in detection rates by using theory-based tools for understanding behavior. We separately studied gastroenterologists and endoscopy nurses at 3 Kaiser Permanente Northern California medical centers to identify potentially modifiable factors relevant to physician adenoma detection rate variability by using structured group interviews (focus groups) and theory-based tools for understanding behavior and eliciting behavior change: the Capability, Opportunity, and Motivation behavior model; the Theoretical Domains Framework; and the Behavior Change Wheel. Nine factors potentially associated with adenoma detection rate variability were identified, including 6 related to capability (uncertainty about which types of polyps to remove, style of endoscopy team leadership, compromised ability to focus during an examination due to distractions, examination technique during withdrawal, difficulty detecting certain types of adenomas, and examiner fatigue and pain), 2 related to opportunity (perceived pressure due to the number of examinations expected per shift and social pressure to finish examinations before scheduled breaks or the end of a shift), and 1 related to motivation (valuing a meticulous examination as the top priority). Examples of potential intervention strategies are provided. By using theory-based tools, this study identified several novel and potentially modifiable factors relating to capability, opportunity, and motivation that may contribute to adenoma detection rate variability and be appropriate targets for future intervention trials. Copyright © 2016 American Society for Gastrointestinal Endoscopy. Published by Elsevier Inc. All rights reserved.

Advanced capabilities for materials modelling with Quantum ESPRESSO.

PubMed

Andreussi, Oliviero; Brumme, Thomas; Bunau, Oana; Buongiorno Nardelli, Marco; Calandra, Matteo; Car, Roberto; Cavazzoni, Carlo; Ceresoli, Davide; Cococcioni, Matteo; Colonna, Nicola; Carnimeo, Ivan; Dal Corso, Andrea; de Gironcoli, Stefano; Delugas, Pietro; DiStasio, Robert; Ferretti, Andrea; Floris, Andrea; Fratesi, Guido; Fugallo, Giorgia; Gebauer, Ralph; Gerstmann, Uwe; Giustino, Feliciano; Gorni, Tommaso; Jia, Junteng; Kawamura, Mitsuaki; Ko, Hsin-Yu; Kokalj, Anton; Küçükbenli, Emine; Lazzeri, Michele; Marsili, Margherita; Marzari, Nicola; Mauri, Francesco; Nguyen, Ngoc Linh; Nguyen, Huy-Viet; Otero-de-la-Roza, Alberto; Paulatto, Lorenzo; Poncé, Samuel; Giannozzi, Paolo; Rocca, Dario; Sabatini, Riccardo; Santra, Biswajit; Schlipf, Martin; Seitsonen, Ari Paavo; Smogunov, Alexander; Timrov, Iurii; Thonhauser, Timo; Umari, Paolo; Vast, Nathalie; Wu, Xifan; Baroni, Stefano

2017-09-27

Quantum ESPRESSO is an integrated suite of open-source computer codes for quantum simulations of materials using state-of-the art electronic-structure techniques, based on density-functional theory, density-functional perturbation theory, and many-body perturbation theory, within the plane-wave pseudo-potential and projector-augmented-wave approaches. Quantum ESPRESSO owes its popularity to the wide variety of properties and processes it allows to simulate, to its performance on an increasingly broad array of hardware architectures, and to a community of researchers that rely on its capabilities as a core open-source development platform to implement theirs ideas. In this paper we describe recent extensions and improvements, covering new methodologies and property calculators, improved parallelization, code modularization, and extended interoperability both within the distribution and with external software. © 2017 IOP Publishing Ltd.

Structure of Salt-free Linear Polyelectrolytes in the Debye-Hückel Approximation

NASA Astrophysics Data System (ADS)

Stevens, Mark J.; Kremer, Kurt

1996-11-01

We examine the effects of the common Debye-Hückel approximation used in theories of polyelectrolytes. Molecular dynamics simulations using the Debye-Hückel pair potential of salt-free polyelectrolytes have been performed. The results of these simulations are compared to earlier “Coulomb" simulations which explicitly treated the counterions. We report here the comparisons of the osmotic pressure, the end-to-end distance and the single chain structure factor. In the dilute regime the Debye-Hückel chains are more elongated than the Coulomb chains implying that the counterion screening is stronger than the Debye-Hückel prediction. Like the Coulomb chains the Debye-Hückel chains contract significantly below the overlap density in contradiction to all theories. Entropy thus plays an important and sorely neglected role in theory.

Kinetics study of the CN + CH4 hydrogen abstraction reaction based on a new ab initio analytical full-dimensional potential energy surface.

PubMed

Espinosa-Garcia, Joaquin; Rangel, Cipriano; Suleimanov, Yury V

2017-07-26

We have developed an analytical full-dimensional potential energy surface, named PES-2017, for the gas-phase hydrogen abstraction reaction between the cyano radical and methane. This surface is fitted using high-level ab initio information as input. Using the PES-2017 surface, a kinetics study was performed via two theoretical approaches: variational transition-state theory with multidimensional tunnelling (VTST-MT) and ring polymer molecular dynamics (RPMD). The results are compared with the experimental data. In the whole temperature range analysed, 300-1500 K, both theories agree within a factor of <2, reproducing the experimental behaviour taking into account the experimental uncertainties. At high temperatures, where the recrossing effects dominate and the RPMD theory is exact, both theories differ by a factor of about 20%; while at low temperatures this difference is larger, 45%. Note that in this temperature regime, the tunnelling effect is negligible. The CN + CH 4 /CD 4 kinetic isotope effects are important, reproducing the scarce experimental evidence. The good agreement with the ab initio information used in the fitting process (self-consistency test) and with the kinetic behaviour in a wide temperature range gives confidence and strength to the new surface.

Personal Goal Setting and Quality of Life: A Mixed Methods Study of Adult Professionals

ERIC Educational Resources Information Center

Ingraham, Frank

2017-01-01

This mixed methods study was designed to examine the potential impactful relationship between personal goal setting and the quality of life satisfaction (built upon the Goal Setting Theory of motivation and performance). The study aimed to determine how influential the goal achievement process is (or is not) regarding personal fulfillment and…

Evaluation of a New Mean Scaled and Moment Adjusted Test Statistic for SEM

ERIC Educational Resources Information Center

Tong, Xiaoxiao; Bentler, Peter M.

2013-01-01

Recently a new mean scaled and skewness adjusted test statistic was developed for evaluating structural equation models in small samples and with potentially nonnormal data, but this statistic has received only limited evaluation. The performance of this statistic is compared to normal theory maximum likelihood and 2 well-known robust test…

Critical Analysis of Textbooks: Knowledge-Generating Logics and the Emerging Image of "Global Economic Contexts"

ERIC Educational Resources Information Center

Thoma, Michael

2017-01-01

This paper presents an approach to the critical analysis of textbook knowledge, which, working from a discourse theory perspective (based on the work of Foucault), refers to the performative nature of language. The critical potential of the approach derives from an analysis of knowledge-generating logics, which produce particular images of reality…

Aspects of Performance on Line Graph Description Tasks: Influenced by Graph Familiarity and Different Task Features

ERIC Educational Resources Information Center

Xi, Xiaoming

2010-01-01

Motivated by cognitive theories of graph comprehension, this study systematically manipulated characteristics of a line graph description task in a speaking test in ways to mitigate the influence of graph familiarity, a potential source of construct-irrelevant variance. It extends Xi (2005), which found that the differences in holistic scores on…

Impossible Practice and Theories of the Impossible: A Response to Helene Illeris's "Potentials of Togetherness"

ERIC Educational Resources Information Center

Kallio-Tavin, Mira

2014-01-01

In a recent commentary in "Studies in Art Education," Helene Illeris (2013) discussed the idea of "performative experimental communities" via a critique of visual culture pedagogy and the romanticism of community-oriented art education in Nordic countries. Illeris underpinned her arguments with Jean-Luc Nancy's (1997)…

The Operator Construct of Rational Numbers in Childhood and Adolescence--An Exploratory Study

ERIC Educational Resources Information Center

Kieren, T. E.; Nelson, D.

1978-01-01

Based on a theory of rational numbers which sees the rational numbers construct of a person as potentially built on a number of subconstructs, this study explored the view of rational numbers as operators. Significant changes in performance level and quality appeared between ages 11 and 12 and 12 and 13. (JC)

Three-dimensional infinite order sudden quantum theory for indirect photodissociation processes. Application to the photofragment yield spectrum of NOCl in the region of the T1(13A″) ←S0(11A') transition. Fragment rotational distributions and thermal averages

NASA Astrophysics Data System (ADS)

Grinberg, Horacio; Freed, Karl F.; Williams, Carl J.

1997-08-01

The analytical infinite order sudden (IOS) quantum theory of triatomic photodissociation, developed in paper I, is applied to study the indirect photodissociation of NOCl through a real or virtual intermediate state. The theory uses the IOS approximation for the dynamics in the final dissociative channels and an Airy function approximation for the continuum functions. The transition is taken as polarized in the plane of the molecule; symmetric top wave functions are used for both the initial and intermediate bound states; and simple semiempirical model potentials are employed for each state. The theory provides analytical expressions for the photofragment yield spectrum for producing particular final fragment ro-vibrational states as a function of the photon excitation energy. Computations are made of the photofragment excitation spectrum of NOCl in the region of the T1(13A″)←S0(11A') transition for producing the NO fragment in the vibrational states nNO=0, 1, and 2. The computed spectra for the unexcited nNO==0 and excited nNO=2 states are in reasonable agreement with experiment. However, some discrepancies are observed for the singly excited nNO=1 vibrational state, indicating deficiencies in the semiempirical potential energy surface. Computations for two different orientations of the in-plane transition dipole moment produce very similar excitation spectra. Calculations of fragment rotational distributions are performed for high values of the total angular momentum J, a feature that would be very difficult to perform with close-coupled methods. Computations are also made of the thermally averaged rotational energy distributions to simulate the conditions in actual supersonic jet experiments.

Dark spectroscopy at lepton colliders

NASA Astrophysics Data System (ADS)

Hochberg, Yonit; Kuflik, Eric; Murayama, Hitoshi

2018-03-01

Rich and complex dark sectors are abundant in particle physics theories. Here, we propose performing spectroscopy of the mass structure of dark sectors via mono-photon searches at lepton colliders. The energy of the mono-photon tracks the invariant mass of the invisible system it recoils against, which enables studying the resonance structure of the dark sector. We demonstrate this idea with several well-motivated models of dark sectors. Such spectroscopy measurements could potentially be performed at Belle II, BES-III and future low-energy lepton colliders.

Unified theory of nonlinear electrodynamics and gravity

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

Torres-Gomez, Alexander; Krasnov, Kirill; Scarinci, Carlos

2011-01-15

We describe a class of unified theories of electromagnetism and gravity. The Lagrangian is of the BF type, with a potential for the B field, the gauge group is U(2) (complexified). Given a choice of the potential function the theory is a deformation of (complex) general relativity and electromagnetism, and describes just two propagating polarizations of the graviton and two of the photon. When gravity is switched off the theory becomes the usual nonlinear electrodynamics with a general structure function. The Einstein-Maxwell theory can be recovered by sending some of the parameters of the defining potential to zero, but formore » any generic choice of the potential the theory is indistinguishable from Einstein-Maxwell at low energies. A real theory is obtained by imposing suitable reality conditions. We also study the spherically-symmetric solution and show how the usual Reissner-Nordstrom solution is recovered.« less

Hamiltonian thermodynamics of charged three-dimensional dilatonic black holes

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

Dias, Goncalo A. S.; Lemos, Jose P. S.; Centro Multidisciplinar de Astrofisica-CENTRA, Departamento de Fisica, Instituto Superior Tecnico-IST, Universidade Tecnica de Lisboa-UTL, Avenida Rovisco Pais 1, 1049-001 Lisboa

2008-10-15

The action for a class of three-dimensional dilaton-gravity theories, with an electromagnetic Maxwell field and a cosmological constant, can be recast in a Brans-Dicke-Maxwell type action, with its free {omega} parameter. For a negative cosmological constant, these theories have static, electrically charged, and spherically symmetric black hole solutions. Those theories with well formulated asymptotics are studied through a Hamiltonian formalism, and their thermodynamical properties are found out. The theories studied are general relativity ({omega}{yields}{+-}{infinity}), a dimensionally reduced cylindrical four-dimensional general relativity theory ({omega}=0), and a theory representing a class of theories ({omega}=-3), all with a Maxwell term. The Hamiltonian formalismmore » is set up in three dimensions through foliations on the right region of the Carter-Penrose diagram, with the bifurcation 1-sphere as the left boundary, and anti-de Sitter infinity as the right boundary. The metric functions on the foliated hypersurfaces and the radial component of the vector potential one-form are the canonical coordinates. The Hamiltonian action is written, the Hamiltonian being a sum of constraints. One finds a new action which yields an unconstrained theory with two pairs of canonical coordinates (M,P{sub M};Q,P{sub Q}), where M is the mass parameter, which for {omega}<-(3/2) and for {omega}={+-}{infinity} needs a careful renormalization, P{sub M} is the conjugate momenta of M, Q is the charge parameter, and P{sub Q} is its conjugate momentum. The resulting Hamiltonian is a sum of boundary terms only. A quantization of the theory is performed. The Schroedinger evolution operator is constructed, the trace is taken, and the partition function of the grand canonical ensemble is obtained, where the chemical potential is the scalar electric field {phi}. Like the uncharged cases studied previously, the charged black hole entropies differ, in general, from the usual quarter of the horizon area due to the dilaton.« less

Thermal density functional theory, ensemble density functional theory, and potential functional theory for warm dense matter

NASA Astrophysics Data System (ADS)

Pribram-Jones, Aurora

Warm dense matter (WDM) is a high energy phase between solids and plasmas, with characteristics of both. It is present in the centers of giant planets, within the earth's core, and on the path to ignition of inertial confinement fusion. The high temperatures and pressures of warm dense matter lead to complications in its simulation, as both classical and quantum effects must be included. One of the most successful simulation methods is density functional theory-molecular dynamics (DFT-MD). Despite great success in a diverse array of applications, DFT-MD remains computationally expensive and it neglects the explicit temperature dependence of electron-electron interactions known to exist within exact DFT. Finite-temperature density functional theory (FT DFT) is an extension of the wildly successful ground-state DFT formalism via thermal ensembles, broadening its quantum mechanical treatment of electrons to include systems at non-zero temperatures. Exact mathematical conditions have been used to predict the behavior of approximations in limiting conditions and to connect FT DFT to the ground-state theory. An introduction to FT DFT is given within the context of ensemble DFT and the larger field of DFT is discussed for context. Ensemble DFT is used to describe ensembles of ground-state and excited systems. Exact conditions in ensemble DFT and the performance of approximations depend on ensemble weights. Using an inversion method, exact Kohn-Sham ensemble potentials are found and compared to approximations. The symmetry eigenstate Hartree-exchange approximation is in good agreement with exact calculations because of its inclusion of an ensemble derivative discontinuity. Since ensemble weights in FT DFT are temperature-dependent Fermi weights, this insight may help develop approximations well-suited to both ground-state and FT DFT. A novel, highly efficient approach to free energy calculations, finite-temperature potential functional theory, is derived, which has the potential to transform the simulation of warm dense matter. As a semiclassical method, it connects the normally disparate regimes of cold condensed matter physics and hot plasma physics. This orbital-free approach captures the smooth classical density envelope and quantum density oscillations that are both crucial to accurate modeling of materials where temperature and pressure effects are influential.

Evaluation of oral microbiology lab curriculum reform.

PubMed

Nie, Min; Gao, Zhen Y; Wu, Xin Y; Jiang, Chen X; Du, Jia H

2015-12-07

According to the updated concept of oral microbiology, the School of Stomatology, Wuhan University, has carried out oral microbiology teaching reforms during the last 5 years. There was no lab curriculum before 2009 except for a theory course of oral microbiology. The school has implemented an innovative curriculum with oral medicine characteristics to strengthen understanding of knowledge, cultivate students' scientific interest and develop their potential, to cultivate the comprehensive ability of students. This study was designed to evaluate the oral microbiology lab curriculum by analyzing student performance and perceptions regarding the curriculum from 2009 to 2013. The lab curriculum adopted modalities for cooperative learning. Students collected dental plaque from each other and isolated the cariogenic bacteria with selective medium plates. Then they purified the enrichment culture medium and identified the cariogenic strains by Gram stain and biochemical tests. Both quantitative and qualitative data for 5 years were analysed in this study. Part One of the current study assessed student performance in the lab from 2009 to 2013. Part Two used qualitative means to assess students' perceptions by an open questionnaire. The 271 study students' grades on oral microbiology improved during the lab curriculum: "A" grades rose from 60.5 to 81.2 %, and "C" grades fell from 28.4 to 6.3 %. All students considered the lab curriculum to be interesting and helpful. Quantitative and qualitative data converge to suggest that the lab curriculum has strengthened students' grasp of important microbiology-related theory, cultivated their scientific interest, and developed their potential and comprehensive abilities. Our student performance and perception data support the continued use of the innovative teaching system. As an extension and complement of the theory course, the oral microbiology lab curriculum appears to improve the quality of oral medicine education and help to cultivate high-quality innovative medical talents.

Interactions between Nanoparticles and Polymer Brushes: Molecular Dynamics Simulations and Self-consistent Field Theory Calculations

NASA Astrophysics Data System (ADS)

Cheng, Shengfeng; Wen, Chengyuan; Egorov, Sergei

2015-03-01

Molecular dynamics simulations and self-consistent field theory calculations are employed to study the interactions between a nanoparticle and a polymer brush at various densities of chains grafted to a plane. Simulations with both implicit and explicit solvent are performed. In either case the nanoparticle is loaded to the brush at a constant velocity. Then a series of simulations are performed to compute the force exerted on the nanoparticle that is fixed at various distances from the grafting plane. The potential of mean force is calculated and compared to the prediction based on a self-consistent field theory. Our simulations show that the explicit solvent leads to effects that are not captured in simulations with implicit solvent, indicating the importance of including explicit solvent in molecular simulations of such systems. Our results also demonstrate an interesting correlation between the force on the nanoparticle and the density profile of the brush. We gratefully acknowledge the support of NVIDIA Corporation with the donation of the Tesla K40 GPU used for this research.

Thermodynamic properties of diamond and wurtzite model fluids from computer simulation and thermodynamic perturbation theory

NASA Astrophysics Data System (ADS)

Zhou, S.; Solana, J. R.

2018-03-01

Monte Carlo NVT simulations have been performed to obtain the thermodynamic and structural properties and perturbation coefficients up to third order in the inverse temperature expansion of the Helmholtz free energy of fluids with potential models proposed in the literature for diamond and wurtzite lattices. These data are used to analyze performance of a coupling parameter series expansion (CPSE). The main findings are summarized as follows, (1) The CPSE provides accurate predictions of the first three coefficient in the inverse temperature expansion of Helmholtz free energy for the potential models considered and the thermodynamic properties of these fluids are predicted more accurately when the CPSE is truncated at second or third order. (2) The Barker-Henderson (BH) recipe is appropriate for determining the effective hard sphere diameter for strongly repulsive potential cores, but its performance worsens with increasing the softness of the potential core. (3) For some thermodynamic properties the first-order CPSE works better for the diamond potential, whose tail is dominated by repulsive interactions, than for the potential, whose tail is dominated by attractive interactions. However, the first-order CPSE provides unsatisfactory results for the excess internal energy and constant-volume excess heat capacity for the two potential models.

DeePMD-kit: A deep learning package for many-body potential energy representation and molecular dynamics

NASA Astrophysics Data System (ADS)

Wang, Han; Zhang, Linfeng; Han, Jiequn; E, Weinan

2018-07-01

Recent developments in many-body potential energy representation via deep learning have brought new hopes to addressing the accuracy-versus-efficiency dilemma in molecular simulations. Here we describe DeePMD-kit, a package written in Python/C++ that has been designed to minimize the effort required to build deep learning based representation of potential energy and force field and to perform molecular dynamics. Potential applications of DeePMD-kit span from finite molecules to extended systems and from metallic systems to chemically bonded systems. DeePMD-kit is interfaced with TensorFlow, one of the most popular deep learning frameworks, making the training process highly automatic and efficient. On the other end, DeePMD-kit is interfaced with high-performance classical molecular dynamics and quantum (path-integral) molecular dynamics packages, i.e., LAMMPS and the i-PI, respectively. Thus, upon training, the potential energy and force field models can be used to perform efficient molecular simulations for different purposes. As an example of the many potential applications of the package, we use DeePMD-kit to learn the interatomic potential energy and forces of a water model using data obtained from density functional theory. We demonstrate that the resulted molecular dynamics model reproduces accurately the structural information contained in the original model.

Symmetry, Contingency, Complexity: Accommodating Uncertainty in Public Relations Theory.

ERIC Educational Resources Information Center

Murphy, Priscilla

2000-01-01

Explores the potential of complexity theory as a unifying theory in public relations, where scholars have recently raised problems involving flux, uncertainty, adaptiveness, and loss of control. Describes specific complexity-based methodologies and their potential for public relations studies. Offers an account of complexity theory, its…

Physician practice management organizations: their prospects and performance.

PubMed

Conrad, D A; Koos, S; Harney, A; Haase, M

1999-09-01

As physician organizations adapt their incentives, processes, and structures to accommodate the demands of an increasingly competitive and performance-sensitive external environment, the development of more effective administrative and managerial mechanisms becomes critical to success. The emergence of physician practice management companies (PPMCs) represents a potentially positive step for physician practices seeking increased economies of scale through consolidation, as well as enhanced access to financial capital. However, economic and finance theory, coupled with some empirical "arithmetic" regarding the financial and operational performance of leading publicly traded PPMCs, suggest caution in one's forecasts of the future prospects for these evolving corporate forms.

Promoting HIV Vaccine Research in African American Communities: Does the Theory of Reasoned Action Explain Potential Outcomes of Involvement?

PubMed Central

Frew, Paula M.; Archibald, Matthew; Martinez, Nina; del Rio, Carlos; Mulligan, Mark J.

2009-01-01

The HIV/AIDS pandemic continues to challenge the African American community with disproportionate rates of infection, particularly among young women ages 25 to 34 years. Development of a preventive HIV vaccine may bring a substantial turning point in this health crisis. Engagement of the African American community is necessary to improve awareness of the effort and favorably influence attitudes and referent norms. The Theory of Reasoned Action (TRA) may be a useful framework for exploration of community engagement outcomes including future attendance, community mobilization, and study participation. Within the context of HIV vaccine outreach, we conducted a cross-sectional survey in early 2007 with 175 African-American adults (≥ 18 years). Confirmatory factor analysis and structural equation modeling were performed and the findings support the potential of the model in understanding behavioral intentions toward HIV vaccine research. PMID:20686675

Promoting HIV Vaccine Research in African American Communities: Does the Theory of Reasoned Action Explain Potential Outcomes of Involvement?

PubMed

Frew, Paula M; Archibald, Matthew; Martinez, Nina; del Rio, Carlos; Mulligan, Mark J

2007-01-01

The HIV/AIDS pandemic continues to challenge the African American community with disproportionate rates of infection, particularly among young women ages 25 to 34 years. Development of a preventive HIV vaccine may bring a substantial turning point in this health crisis. Engagement of the African American community is necessary to improve awareness of the effort and favorably influence attitudes and referent norms. The Theory of Reasoned Action (TRA) may be a useful framework for exploration of community engagement outcomes including future attendance, community mobilization, and study participation. Within the context of HIV vaccine outreach, we conducted a cross-sectional survey in early 2007 with 175 African-American adults (>/= 18 years). Confirmatory factor analysis and structural equation modeling were performed and the findings support the potential of the model in understanding behavioral intentions toward HIV vaccine research.

Zooming in on neutrino oscillations with DUNE

NASA Astrophysics Data System (ADS)

Srivastava, Rahul; Ternes, Christoph A.; Tórtola, Mariam; Valle, José W. F.

2018-05-01

We examine the capabilities of the DUNE experiment as a probe of the neutrino mixing paradigm. Taking the current status of neutrino oscillations and the design specifications of DUNE, we determine the experiment's potential to probe the structure of neutrino mixing and C P violation. We focus on the poorly determined parameters θ23 and δC P and consider both two and seven years of run. We take various benchmarks as our true values, such as the current preferred values of θ23 and δC P, as well as several theory-motivated choices. We determine quantitatively DUNE's potential to perform a precision measurement of θ23, as well as to test the C P violation hypothesis in a model-independent way. We find that, after running for seven years, DUNE will make a substantial step in the precise determination of these parameters, bringing to quantitative test the predictions of various theories of neutrino mixing.

A molecular theory for optimal blue energy extraction by electrical double layer expansion

DOE PAGES

Kong, Xian; Gallegos, Alejandro; Lu, Diannan; ...

2015-08-19

We proposed the electrical double layer expansion (CDLE) as a promising alternative to reverse electrodialysis (RED) and pressure retarded osmosis (PRO) processes for extracting osmotic power generated by the salinity difference between freshwater and seawater. The performance of the CDLE process is sensitive to the configuration of porous electrodes and operation parameters for ion extraction and release cycles. In our work, we use a classical density functional theory (CDFT) to examine how the electrode pore size and charging/discharging potentials influence the thermodynamic efficiency of the CDLE cycle. The existence of an optimal charging potential that maximizes the energy output formore » a given pore configuration is predicted, which varies substantially with the pore size, especially when it is smaller than 2 nm. Finally, the thermodynamic efficiency is maximized when the electrode has a pore size about twice the ion diameter.« less

Gravitational effective action at second order in curvature and gravitational waves

NASA Astrophysics Data System (ADS)

Calmet, Xavier; Capozziello, Salvatore; Pryer, Daniel

2017-09-01

We consider the full effective theory for quantum gravity at second order in curvature including non-local terms. We show that the theory contains two new degrees of freedom beyond the massless graviton: namely a massive spin-2 ghost and a massive scalar field. Furthermore, we show that it is impossible to fine-tune the parameters of the effective action to eliminate completely the classical spin-2 ghost because of the non-local terms in the effective action. Being a classical field, it is not clear anyway that this ghost is problematic. It simply implies a repulsive contribution to Newton's potential. We then consider how to extract the parameters of the effective action and show that it is possible to measure, at least in principle, the parameters of the local terms independently of each other using a combination of observations of gravitational waves and measurements performed by pendulum type experiments searching for deviations of Newton's potential.

Two-dimensional nitrides as highly efficient potential candidates for CO2 capture and activation.

PubMed

Morales-Salvador, Raul; Morales-García, Ángel; Viñes, Francesc; Illas, Francesc

2018-06-13

The performance of novel two-dimensional nitrides in carbon capture and storage (CCS) is analyzed for a broad range of pressures and temperatures. Employing an integrated theoretical framework where CO2 adsorption/desorption rates on the M2N (M = Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, and W) surfaces are derived from transition state theory and density functional theory based calculations, the present theoretical simulations consistently predict that, depending on the particular composition, CO2 can be strongly adsorbed and even activated at temperatures above 1000 K. For practical purposes, Ti2N, Zr2N, Hf2N, V2N, Nb2N, and Ta2N are predicted as the best suited materials for CO2 activation. Moreover, the estimated CO2 uptake of 2.32-7.96 mol CO2 kg-1 reinforces the potential of these materials for CO2 abatement.

Teaching a lay theory before college narrows achievement gaps at scale.

PubMed

Yeager, David S; Walton, Gregory M; Brady, Shannon T; Akcinar, Ezgi N; Paunesku, David; Keane, Laura; Kamentz, Donald; Ritter, Gretchen; Duckworth, Angela Lee; Urstein, Robert; Gomez, Eric M; Markus, Hazel Rose; Cohen, Geoffrey L; Dweck, Carol S

2016-06-14

Previous experiments have shown that college students benefit when they understand that challenges in the transition to college are common and improvable and, thus, that early struggles need not portend a permanent lack of belonging or potential. Could such an approach-called a lay theory intervention-be effective before college matriculation? Could this strategy reduce a portion of racial, ethnic, and socioeconomic achievement gaps for entire institutions? Three double-blind experiments tested this possibility. Ninety percent of first-year college students from three institutions were randomly assigned to complete single-session, online lay theory or control materials before matriculation (n > 9,500). The lay theory interventions raised first-year full-time college enrollment among students from socially and economically disadvantaged backgrounds exiting a high-performing charter high school network or entering a public flagship university (experiments 1 and 2) and, at a selective private university, raised disadvantaged students' cumulative first-year grade point average (experiment 3). These gains correspond to 31-40% reductions of the raw (unadjusted) institutional achievement gaps between students from disadvantaged and nondisadvantaged backgrounds at those institutions. Further, follow-up surveys suggest that the interventions improved disadvantaged students' overall college experiences, promoting use of student support services and the development of friendship networks and mentor relationships. This research therefore provides a basis for further tests of the generalizability of preparatory lay theories interventions and of their potential to reduce social inequality and improve other major life transitions.

A coupled cluster theory with iterative inclusion of triple excitations and associated equation of motion formulation for excitation energy and ionization potential

NASA Astrophysics Data System (ADS)

Maitra, Rahul; Akinaga, Yoshinobu; Nakajima, Takahito

2017-08-01

A single reference coupled cluster theory that is capable of including the effect of connected triple excitations has been developed and implemented. This is achieved by regrouping the terms appearing in perturbation theory and parametrizing through two different sets of exponential operators: while one of the exponentials, involving general substitution operators, annihilates the ground state but has a non-vanishing effect when it acts on the excited determinant, the other is the regular single and double excitation operator in the sense of conventional coupled cluster theory, which acts on the Hartree-Fock ground state. The two sets of operators are solved as coupled non-linear equations in an iterative manner without significant increase in computational cost than the conventional coupled cluster theory with singles and doubles excitations. A number of physically motivated and computationally advantageous sufficiency conditions are invoked to arrive at the working equations and have been applied to determine the ground state energies of a number of small prototypical systems having weak multi-reference character. With the knowledge of the correlated ground state, we have reconstructed the triple excitation operator and have performed equation of motion with coupled cluster singles, doubles, and triples to obtain the ionization potential and excitation energies of these molecules as well. Our results suggest that this is quite a reasonable scheme to capture the effect of connected triple excitations as long as the ground state remains weakly multi-reference.

Teaching a lay theory before college narrows achievement gaps at scale

PubMed Central

Yeager, David S.; Walton, Gregory M.; Brady, Shannon T.; Akcinar, Ezgi N.; Paunesku, David; Keane, Laura; Kamentz, Donald; Ritter, Gretchen; Duckworth, Angela Lee; Urstein, Robert; Gomez, Eric M.; Markus, Hazel Rose; Cohen, Geoffrey L.; Dweck, Carol S.

2016-01-01

Previous experiments have shown that college students benefit when they understand that challenges in the transition to college are common and improvable and, thus, that early struggles need not portend a permanent lack of belonging or potential. Could such an approach—called a lay theory intervention—be effective before college matriculation? Could this strategy reduce a portion of racial, ethnic, and socioeconomic achievement gaps for entire institutions? Three double-blind experiments tested this possibility. Ninety percent of first-year college students from three institutions were randomly assigned to complete single-session, online lay theory or control materials before matriculation (n > 9,500). The lay theory interventions raised first-year full-time college enrollment among students from socially and economically disadvantaged backgrounds exiting a high-performing charter high school network or entering a public flagship university (experiments 1 and 2) and, at a selective private university, raised disadvantaged students’ cumulative first-year grade point average (experiment 3). These gains correspond to 31–40% reductions of the raw (unadjusted) institutional achievement gaps between students from disadvantaged and nondisadvantaged backgrounds at those institutions. Further, follow-up surveys suggest that the interventions improved disadvantaged students’ overall college experiences, promoting use of student support services and the development of friendship networks and mentor relationships. This research therefore provides a basis for further tests of the generalizability of preparatory lay theories interventions and of their potential to reduce social inequality and improve other major life transitions. PMID:27247409

Multitasking as a choice: a perspective.

PubMed

Broeker, Laura; Liepelt, Roman; Poljac, Edita; Künzell, Stefan; Ewolds, Harald; de Oliveira, Rita F; Raab, Markus

2018-01-01

Performance decrements in multitasking have been explained by limitations in cognitive capacity, either modelled as static structural bottlenecks or as the scarcity of overall cognitive resources that prevent humans, or at least restrict them, from processing two tasks at the same time. However, recent research has shown that individual differences, flexible resource allocation, and prioritization of tasks cannot be fully explained by these accounts. We argue that understanding human multitasking as a choice and examining multitasking performance from the perspective of judgment and decision-making (JDM), may complement current dual-task theories. We outline two prominent theories from the area of JDM, namely Simple Heuristics and the Decision Field Theory, and adapt these theories to multitasking research. Here, we explain how computational modelling techniques and decision-making parameters used in JDM may provide a benefit to understanding multitasking costs and argue that these techniques and parameters have the potential to predict multitasking behavior in general, and also individual differences in behavior. Finally, we present the one-reason choice metaphor to explain a flexible use of limited capacity as well as changes in serial and parallel task processing. Based on this newly combined approach, we outline a concrete interdisciplinary future research program that we think will help to further develop multitasking research.

Exploring Increased Productivity Through Employee Engagement

NASA Astrophysics Data System (ADS)

Richards, Wayne K., Jr.

Disengaged employees cost U.S. companies billions of dollars annually in lowered productivity, a cost which has been compounded by the difficult economic situations in the country. The potential for increasing productivity through increased employee engagement was examined in this study. Using personal engagement theory and the theory of planned behavior, the purpose of this phenomenological study was to explore how the experiences of salaried aerospace employees affected productivity and the financial performance of an organization. Interviews were conducted with a purposive sample of 20 aerospace employees whose responses were codified and analyzed to identify themes. The analysis indicated that (a) the lived experiences of employees influenced employee engagement, (b) employee engagement affects organizational commitment and performance, and (c) trust and respect and leadership are essential components to keep employees engaged. Eighty percent of the participants indicated that as employee engagement increases so too does organizational performance. The implications for positive social change include new insights for leaders seeking to increase productivity and financial performance, and to support employee engagement for maintaining sustainability, retaining talent, increasing profits, and improving the economy.

Cognitive therapy for performance anxiety.

PubMed

Rodebaugh, Thomas L; Chambless, Dianne L

2004-08-01

We present and illustrate the major components of cognitive therapy for performance anxiety, focusing on the performance fears of a client treated with a protocol designed for social phobia. The basic supposition of cognitive theory is that a client's thoughts and beliefs about situations maintain distressing feelings, such as anxiety. Changing these beliefs involves detection and disputation of anxiety-provoking thoughts, as well as testing of these thoughts through exposure to feared situations. Through a process of identifying existing beliefs about performance situations and challenging these beliefs, clients can gain a more realistic and less anxiety-producing perspective on performance tasks. Specific techniques, along with common difficulties and potential solutions, are presented in a detailed case study. Copyright 2004 Wiley Periodicals, Inc.

Multispectral iris recognition based on group selection and game theory

NASA Astrophysics Data System (ADS)

Ahmad, Foysal; Roy, Kaushik

2017-05-01

A commercially available iris recognition system uses only a narrow band of the near infrared spectrum (700-900 nm) while iris images captured in the wide range of 405 nm to 1550 nm offer potential benefits to enhance recognition performance of an iris biometric system. The novelty of this research is that a group selection algorithm based on coalition game theory is explored to select the best patch subsets. In this algorithm, patches are divided into several groups based on their maximum contribution in different groups. Shapley values are used to evaluate the contribution of patches in different groups. Results show that this group selection based iris recognition

Aerodynamic preliminary analysis system 2. Part 1: Theory

NASA Technical Reports Server (NTRS)

Bonner, E.; Clever, W.; Dunn, K.

1991-01-01

An aerodynamic analysis system based on potential theory at subsonic and/or supersonic speeds and impact type finite element solutions at hypersonic conditions is described. Three dimensional configurations having multiple nonplanar surfaces of arbitrary planform and bodies of noncircular contour may be analyzed. Static, rotary, and control longitudinal and lateral directional characteristics may be generated. The analysis was implemented on a time sharing system in conjunction with an input tablet digitizer and an interactive graphics input/output display and editing terminal to maximize its responsiveness to the preliminary analysis problem. The program provides an efficient analysis for systematically performing various aerodynamic configuration tradeoff and evaluation studies.

Portfolio: a comprehensive method of assessment for postgraduates in oral and maxillofacial surgery.

PubMed

Kadagad, Poornima; Kotrashetti, S M

2013-03-01

Post graduate learning and assessment is an important responsibility of an academic oral and maxillofacial surgeon. The current method of assessment for post graduate training include formative evaluation in the form of seminars, case presentations, log books and infrequently conducted end of year theory exams. End of the course theory and practical examination is a summative evaluation which awards the degree to the student based on grades obtained. Oral and maxillofacial surgery is mainly a skill based specialty and deliberate practice enhances skill. But the traditional system of assessment of post graduates emphasizes their performance on the summative exam which fails to evaluate the integral picture of the student throughout the course. Emphasis on competency and holistic growth of the post graduate student during training in recent years has lead to research and evaluation of assessment methods to quantify students' progress during training. Portfolio method of assessment has been proposed as a potentially functional method for post graduate evaluation. It is defined as a collection of papers and other forms of evidence that learning has taken place. It allows the collation and integration of evidence on competence and performance from different sources to gain a comprehensive picture of everyday practice. The benefits of portfolio assessment in health professions education are twofold: it's potential to assess performance and its potential to assess outcomes, such as attitudes and professionalism that are difficult to assess using traditional instruments. This paper is an endeavor for the development of portfolio method of assessment for post graduate student in oral and maxillofacial surgery.

Measures and Interpretations of Vigilance Performance: Evidence Against the Detection Criterion

NASA Technical Reports Server (NTRS)

Balakrishnan, J. D.

1998-01-01

Operators' performance in a vigilance task is often assumed to depend on their choice of a detection criterion. When the signal rate is low this criterion is set high, causing the hit and false alarm rates to be low. With increasing time on task the criterion presumably tends to increase even further, thereby further decreasing the hit and false alarm rates. Virtually all of the empirical evidence for this simple interpretation is based on estimates of the bias measure Beta from signal detection theory. In this article, I describe a new approach to studying decision making that does not require the technical assumptions of signal detection theory. The results of this new analysis suggest that the detection criterion is never biased toward either response, even when the signal rate is low and the time on task is long. Two modifications of the signal detection theory framework are considered to account for this seemingly paradoxical result. The first assumes that the signal rate affects the relative sizes of the variances of the information distributions; the second assumes that the signal rate affects the logic of the operator's stopping rule. Actual or potential applications of this research include the improved training and performance assessment of operators in areas such as product quality control, air traffic control, and medical and clinical diagnosis.

Story Immersion of Videogames for Youth Health Promotion: A Review of Literature

PubMed Central

Baranowski, Tom; Thompson, Debbe; Buday, Richard

2012-01-01

Abstract This article reviews research in the fields of psychology, literature, communication, human–computer interaction, public health, and consumer behavior on narrative and its potential relationships with videogames and story immersion. It also reviews a narrative's role in complementing behavioral change theories and the potential of story immersion for health promotion through videogames. Videogames have potential for health promotion and may be especially promising when attempting to reach youth. An understudied characteristic of videogames is that many contain a narrative, or story. Story immersion (transportation) is a mechanism through which a narrative influences players' cognition, affect, and, potentially, health behavior. Immersion promotes the suspension of disbelief and the reduction of counterarguments, enables the story experience as a personal experience, and creates the player's deep affection for narrative protagonists. Story immersion complements behavioral change theories, including the Theory of Planned Behavior, Social Cognitive Theory, and Self-Determination Theory. Systematic investigations are needed to realize the powerful potential of interactive narratives within theory-driven research. PMID:24416639

Story Immersion of Videogames for Youth Health Promotion: A Review of Literature.

PubMed

Lu, Amy Shirong; Baranowski, Tom; Thompson, Debbe; Buday, Richard

2012-06-01

This article reviews research in the fields of psychology, literature, communication, human-computer interaction, public health, and consumer behavior on narrative and its potential relationships with videogames and story immersion. It also reviews a narrative's role in complementing behavioral change theories and the potential of story immersion for health promotion through videogames. Videogames have potential for health promotion and may be especially promising when attempting to reach youth. An understudied characteristic of videogames is that many contain a narrative, or story. Story immersion (transportation) is a mechanism through which a narrative influences players' cognition, affect, and, potentially, health behavior. Immersion promotes the suspension of disbelief and the reduction of counterarguments, enables the story experience as a personal experience, and creates the player's deep affection for narrative protagonists. Story immersion complements behavioral change theories, including the Theory of Planned Behavior, Social Cognitive Theory, and Self-Determination Theory. Systematic investigations are needed to realize the powerful potential of interactive narratives within theory-driven research.

Evidence for Trait Related Theory of Mind Impairment in First Episode Psychosis Patients and Its Relationship with Processing Speed: A 3 Year Follow-up Study.

PubMed

Ayesa-Arriola, Rosa; Setién-Suero, Esther; Neergaard, Karl D; Ferro, Adele; Fatjó-Vilas, Mar; Ríos-Lago, Marcos; Otero, Soraya; Rodríguez-Sánchez, Jose M; Crespo-Facorro, Benedicto

2016-01-01

This study aimed to confirm whether first-episode psychosis patients present a stable trait impairment in theory of mind (ToM) and to examine the potential relationship between ToM and clinical symptomatology and neurocognition. Patients with a first episode of psychosis (N = 160) and healthy controls (N = 159) were assessed with an extensive neuropsychological test battery, which included a mental state decoding task known as "The Reading the Mind in the Eyes" (Eyes test), at baseline and reassessed after 1 and 3 years. The clinical group performed below healthy controls on the Eyes test while not showing test-retest differences between baseline and follow-up administrations. Analyses revealed age, education and premorbid IQ as potential moderators. Poorer performance on the Eyes test was not linked to clinical symptomatology but was associated with greater neurocognitive deficit, particularly related to processing speed. The persistence of ToM deficits in patients suggests that there are trait related metalizing impairments in first episode psychosis. This study shows the influence of processing speed and moderator variables on efficient ToM.

Evidence for Trait Related Theory of Mind Impairment in First Episode Psychosis Patients and Its Relationship with Processing Speed: A 3 Year Follow-up Study

PubMed Central

Ayesa-Arriola, Rosa; Setién-Suero, Esther; Neergaard, Karl D.; Ferro, Adele; Fatjó-Vilas, Mar; Ríos-Lago, Marcos; Otero, Soraya; Rodríguez-Sánchez, Jose M.; Crespo-Facorro, Benedicto

2016-01-01

This study aimed to confirm whether first-episode psychosis patients present a stable trait impairment in theory of mind (ToM) and to examine the potential relationship between ToM and clinical symptomatology and neurocognition. Patients with a first episode of psychosis (N = 160) and healthy controls (N = 159) were assessed with an extensive neuropsychological test battery, which included a mental state decoding task known as “The Reading the Mind in the Eyes” (Eyes test), at baseline and reassessed after 1 and 3 years. The clinical group performed below healthy controls on the Eyes test while not showing test-retest differences between baseline and follow-up administrations. Analyses revealed age, education and premorbid IQ as potential moderators. Poorer performance on the Eyes test was not linked to clinical symptomatology but was associated with greater neurocognitive deficit, particularly related to processing speed. The persistence of ToM deficits in patients suggests that there are trait related metalizing impairments in first episode psychosis. This study shows the influence of processing speed and moderator variables on efficient ToM. PMID:27199826

Potential theory of radiation

NASA Technical Reports Server (NTRS)

Chiu, Huei-Huang

1989-01-01

A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.

Attractive potential around a thermionically emitting microparticle.

PubMed

Delzanno, G L; Lapenta, G; Rosenberg, M

2004-01-23

We present a simulation study of the charging of a dust grain immersed in a plasma, considering the effect of thermionic electron emission from the grain. It is shown that the orbit motion limited theory is no longer reliable when electron emission becomes large: screening can no longer be treated within the Debye-Huckel approach and an attractive potential well can form, leading to the possibility of attractive forces on other grains with the same polarity. We suggest to perform laboratory experiments where emitting dust grains could be used to create nonconventional dust crystals or macromolecules.

How to Improve Adolescent Stress Responses: Insights From Integrating Implicit Theories of Personality and Biopsychosocial Models.

PubMed

Yeager, David S; Lee, Hae Yeon; Jamieson, Jeremy P

2016-08-01

This research integrated implicit theories of personality and the biopsychosocial model of challenge and threat, hypothesizing that adolescents would be more likely to conclude that they can meet the demands of an evaluative social situation when they were taught that people have the potential to change their socially relevant traits. In Study 1 (N = 60), high school students were assigned to an incremental-theory-of-personality or a control condition and then given a social-stress task. Relative to control participants, incremental-theory participants exhibited improved stress appraisals, more adaptive neuroendocrine and cardiovascular responses, and better performance outcomes. In Study 2 (N = 205), we used a daily-diary intervention to test high school students' stress reactivity outside the laboratory. Threat appraisals (Days 5-9 after intervention) and neuroendocrine responses (Days 8 and 9 after intervention only) were unrelated to the intensity of daily stressors when adolescents received the incremental-theory intervention. Students who received the intervention also had better grades over freshman year than those who did not. These findings offer new avenues for improving theories of adolescent stress and coping. © The Author(s) 2016.

Preparation and Application of Electrodes in Capacitive Deionization (CDI): a State-of-Art Review.

PubMed

Jia, Baoping; Zhang, Wei

2016-12-01

As a promising desalination technology, capacitive deionization (CDI) have shown practicality and cost-effectiveness in brackish water treatment. Developing more efficient electrode materials is the key to improving salt removal performance. This work reviewed current progress on electrode fabrication in application of CDI. Fundamental principal (e.g. EDL theory and adsorption isotherms) and process factors (e.g. pore distribution, potential, salt type and concentration) of CDI performance were presented first. It was then followed by in-depth discussion and comparison on properties and fabrication technique of different electrodes, including carbon aerogel, activated carbon, carbon nanotubes, graphene and ordered mesoporous carbon. Finally, polyaniline as conductive polymer and its potential application as CDI electrode-enhancing materials were also discussed.

A performance analysis of ensemble averaging for high fidelity turbulence simulations at the strong scaling limit

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

Makarashvili, Vakhtang; Merzari, Elia; Obabko, Aleksandr

We analyze the potential performance benefits of estimating expected quantities in large eddy simulations of turbulent flows using true ensembles rather than ergodic time averaging. Multiple realizations of the same flow are simulated in parallel, using slightly perturbed initial conditions to create unique instantaneous evolutions of the flow field. Each realization is then used to calculate statistical quantities. Provided each instance is sufficiently de-correlated, this approach potentially allows considerable reduction in the time to solution beyond the strong scaling limit for a given accuracy. This study focuses on the theory and implementation of the methodology in Nek5000, a massively parallelmore » open-source spectral element code.« less

A performance analysis of ensemble averaging for high fidelity turbulence simulations at the strong scaling limit

DOE PAGES

Makarashvili, Vakhtang; Merzari, Elia; Obabko, Aleksandr; ...

2017-06-07

We analyze the potential performance benefits of estimating expected quantities in large eddy simulations of turbulent flows using true ensembles rather than ergodic time averaging. Multiple realizations of the same flow are simulated in parallel, using slightly perturbed initial conditions to create unique instantaneous evolutions of the flow field. Each realization is then used to calculate statistical quantities. Provided each instance is sufficiently de-correlated, this approach potentially allows considerable reduction in the time to solution beyond the strong scaling limit for a given accuracy. This study focuses on the theory and implementation of the methodology in Nek5000, a massively parallelmore » open-source spectral element code.« less

A comparative test of the theory of reasoned action and the theory of planned behavior in the prediction of condom use intentions in a national sample of English young people.

PubMed

Sutton, S; McVey, D; Glanz, A

1999-01-01

Based on the theories of reasoned action (TRA) and planned behavior (TPB), predictors of condom use intentions were investigated in 949 young people (16-24 years of age) from a national survey conducted in England. Contrary to expectations, the TPB did not perform significantly better than the TRA, even among women. Measures of past behavior were the best predictors of intentions and attenuated the effects of attitude and subjective norm. There was only weak evidence for the multiplicative assumption underlying the TRA and TPB. Although the TRA components were not the strongest predictors, the beliefs on which they are based are potentially amenable to change through information-based intervention programs. A number of practical suggestions for developing intervention strategies are offered.

Geographical thinking in nursing inquiry, part two: performance, possibility, and non-representational theory.

PubMed

Andrews, Gavin J

2017-04-01

Part one in this two paper series reviewed the nature of geographical thinking in nursing research thus far. The current paper builds on it by looking forwards and providing a particular vision for future research. It argues that it is time to once again look to the parent discipline of human geography for inspiration, specifically to its turn towards non-representational theory, involving an emphasis on life that onflows prior to meaning, significance, and full cognition; on life's 'taking-place'. The paper introduces this way of viewing and animating the world. Some potential connections to nursing research and practice are suggested, as are some specific avenues for future inquiry. Explained is how, through non-representational theory, nursing might be re-imagined as something that reveals space-time. © 2016 John Wiley & Sons Ltd.

Explicit polarization (X-Pol) potential using ab initio molecular orbital theory and density functional theory.

PubMed

Song, Lingchun; Han, Jaebeom; Lin, Yen-lin; Xie, Wangshen; Gao, Jiali

2009-10-29

The explicit polarization (X-Pol) method has been examined using ab initio molecular orbital theory and density functional theory. The X-Pol potential was designed to provide a novel theoretical framework for developing next-generation force fields for biomolecular simulations. Importantly, the X-Pol potential is a general method, which can be employed with any level of electronic structure theory. The present study illustrates the implementation of the X-Pol method using ab initio Hartree-Fock theory and hybrid density functional theory. The computational results are illustrated by considering a set of bimolecular complexes of small organic molecules and ions with water. The computed interaction energies and hydrogen bond geometries are in good accord with CCSD(T) calculations and B3LYP/aug-cc-pVDZ optimizations.

Psychoacoustic entropy theory and its implications for performance practice

NASA Astrophysics Data System (ADS)

Strohman, Gregory J.

This dissertation attempts to motivate, derive and imply potential uses for a generalized perceptual theory of musical harmony called psychoacoustic entropy theory. This theory treats the human auditory system as a physical system which takes acoustic measurements. As a result, the human auditory system is subject to all the appropriate uncertainties and limitations of other physical measurement systems. This is the theoretic basis for defining psychoacoustic entropy. Psychoacoustic entropy is a numerical quantity which indexes the degree to which the human auditory system perceives instantaneous disorder within a sound pressure wave. Chapter one explains the importance of harmonic analysis as a tool for performance practice. It also outlines the critical limitations for many of the most influential historical approaches to modeling harmonic stability, particularly when compared to available scientific research in psychoacoustics. Rather than analyze a musical excerpt, psychoacoustic entropy is calculated directly from sound pressure waves themselves. This frames psychoacoustic entropy theory in the most general possible terms as a theory of musical harmony, enabling it to be invoked for any perceivable sound. Chapter two provides and examines many widely accepted mathematical models of the acoustics and psychoacoustics of these sound pressure waves. Chapter three introduces entropy as a precise way of measuring perceived uncertainty in sound pressure waves. Entropy is used, in combination with the acoustic and psychoacoustic models introduced in chapter two, to motivate the mathematical formulation of psychoacoustic entropy theory. Chapter four shows how to use psychoacoustic entropy theory to analyze the certain types of musical harmonies, while chapter five applies the analytical tools developed in chapter four to two short musical excerpts to influence their interpretation. Almost every form of harmonic analysis invokes some degree of mathematical reasoning. However, the limited scope of most harmonic systems used for Western common practice music greatly simplifies the necessary level of mathematical detail. Psychoacoustic entropy theory requires a greater deal of mathematical complexity due to its sheer scope as a generalized theory of musical harmony. Fortunately, under specific assumptions the theory can take on vastly simpler forms. Psychoacoustic entropy theory appears to be highly compatible with the latest scientific research in psychoacoustics. However, the theory itself should be regarded as a hypothesis and this dissertation an experiment in progress. The evaluation of psychoacoustic entropy theory as a scientific theory of human sonic perception must wait for more rigorous future research.

Synaptic Transmission Optimization Predicts Expression Loci of Long-Term Plasticity.

PubMed

Costa, Rui Ponte; Padamsey, Zahid; D'Amour, James A; Emptage, Nigel J; Froemke, Robert C; Vogels, Tim P

2017-09-27

Long-term modifications of neuronal connections are critical for reliable memory storage in the brain. However, their locus of expression-pre- or postsynaptic-is highly variable. Here we introduce a theoretical framework in which long-term plasticity performs an optimization of the postsynaptic response statistics toward a given mean with minimal variance. Consequently, the state of the synapse at the time of plasticity induction determines the ratio of pre- and postsynaptic modifications. Our theory explains the experimentally observed expression loci of the hippocampal and neocortical synaptic potentiation studies we examined. Moreover, the theory predicts presynaptic expression of long-term depression, consistent with experimental observations. At inhibitory synapses, the theory suggests a statistically efficient excitatory-inhibitory balance in which changes in inhibitory postsynaptic response statistics specifically target the mean excitation. Our results provide a unifying theory for understanding the expression mechanisms and functions of long-term synaptic transmission plasticity. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Density matrix perturbation theory for magneto-optical response of periodic insulators

NASA Astrophysics Data System (ADS)

Lebedeva, Irina; Tokatly, Ilya; Rubio, Angel

2015-03-01

Density matrix perturbation theory offers an ideal theoretical framework for the description of response of solids to arbitrary electromagnetic fields. In particular, it allows to consider perturbations introduced by uniform electric and magnetic fields under periodic boundary conditions, though the corresponding potentials break the translational invariance of the Hamiltonian. We have implemented the density matrix perturbation theory in the open-source Octopus code on the basis of the efficient Sternheimer approach. The procedures for responses of different order to electromagnetic fields, including electric polarizability, orbital magnetic susceptibility and magneto-optical response, have been developed and tested by comparison with the results for finite systems and for wavefunction-based perturbation theory, which is already available in the code. Additional analysis of the orbital magneto-optical response is performed on the basis of analytical models. Symmetry limitations to observation of the magneto-optical response are discussed. The financial support from the Marie Curie Fellowship PIIF-GA-2012-326435 (RespSpatDisp) is gratefully acknowledged.

The causal theory of the resting potential of cells.

PubMed

Jäckle, Josef

2007-12-07

In this pedagogical article the causal theory of the resting potential of cells is presented, which for given extracellular ion concentrations predicts the intracellular ones simultaneously with the resting potential. In addition to the Na, K-pump, fixed charges on the membrane surfaces are taken into account. The equation determining the resting potential in the causal theory suggests a new explanation of the genesis of the resting potential. The usual criterion for an ion pump to be electrogenic is not relevant for the whole of the resting potential, and may therefore be misleading. The physical meaning of the Goldman-Hodgkin-Katz formula for the membrane potential as a diffusion potential is also explained and tested with numbers for the giant axon of the squid. A significant discrepancy between theory and experiment is found which calls for an experimental re-examination of the constitutive equations for passive potassium and sodium currents.

Stereotype Threat and College Academic Performance: A Latent Variables Approach*

PubMed Central

Owens, Jayanti; Massey, Douglas S.

2013-01-01

Stereotype threat theory has gained experimental and survey-based support in helping explain the academic underperformance of minority students at selective colleges and universities. Stereotype threat theory states that minority students underperform because of pressures created by negative stereotypes about their racial group. Past survey-based studies, however, are characterized by methodological inefficiencies and potential biases: key theoretical constructs have only been measured using summed indicators and predicted relationships modeled using ordinary least squares. Using the National Longitudinal Survey of Freshman, this study overcomes previous methodological shortcomings by developing a latent construct model of stereotype threat. Theoretical constructs and equations are estimated simultaneously from multiple indicators, yielding a more reliable, valid, and parsimonious test of key propositions. Findings additionally support the view that social stigma can indeed have strong negative effects on the academic performance of pejoratively stereotyped racial-minority group members, not only in laboratory settings, but also in the real world. PMID:23950616

Synthesis, crystal structures, computational studies and antimicrobial activity of new designed bis((5-aryl-1,3,4-oxadiazol-2-yl)thio)alkanes

NASA Astrophysics Data System (ADS)

Ahmed, Muhammad Naeem; Sadiq, Beenish; Al-Masoudi, Najim A.; Yasin, Khawaja Ansar; Hameed, Shahid; Mahmood, Tariq; Ayub, Khurshid; Tahir, Muhammad Nawaz

2018-03-01

A new series of bis((5-aryl-1,3,4-oxadiazol-2-yl)thio)alkanes 4-14 have been synthesized via nucleophilic substitution reaction of dihaloalkanes with respective 1,3,4-oxadiazole-2-thiols 3a-f, and characterized by spectroscopic techniques. The structures of 4 and 12 were unambiguously confirmed by single-crystal X-ray diffraction analysis. Density functional theory calculations at B3LYP/6-31 + G(d) level of theory were performed for comparison of X-ray geometric parameters, molecular electrostatic potential (MEP) and frontier molecular orbital analyses of synthesized compounds. MEP analysis revealed that these compounds are nucleophilic in nature. Frontier molecular orbitals (FMOs) analysis of 4-14 was performed for evaluation of kinetic stability. All synthesized compounds were screened in vitro for antimicrobial activity against three bacterial and three fungal strains and showed promising results.

Numerical exploration of the string theory landscape

NASA Astrophysics Data System (ADS)

Metallinos, Konstantinos

String theory is the best candidate to provide a consistent quantum theory of gravity. Its ten dimensional formulation forces us to perform a compactification of the six unobserved dimensions in a very special compact manifold known as Calabi-Yau. The standard way to address this issue is through the flux compactification scenarios. One of the major implications of these scenarios is that the string theory cannot provide a single and unique vacuum as a solution. Rather one can find an extremely large set of solutions, each with its own physical properties. This is the string theory Landscape. In the first part we present the formal description of the flux compactification theory. From the four dimensional point of view this is a supersymmetric theory, fully described only by two functions, the superpotential and the Kahler potential. Their expressions are crucially depend on the geometrical properties of the compact manifold. By writing these functions for the specific Calabi-Yau manifold P41,1,1,6,9 we are looking firstly for supersymmetric and then after breaking the supersymmetry, for non-supersymmetric numerical solutions. These solutions describe the possible vacua and our goal is using statistical analysis to categorize them based on their cosmological properties and to check their stability. Finally we present the existence of stable dS vacua with and without adding an uplifting term on the potential. In the case where there is not an uplifting term the breaking of supersymmetry is done by incorporating alpha' corrections to the Kahler potential. In the second part we construct a KKLT like inflation model, within string theory flux compactifications and, in particular a model of accidental inflation. We investigate the possibility that the apparent fine-tuning of the low energy parameters of the theory needed to have inflation can be generically obtained by scanning the values of the fluxes over the landscape. Furthermore, we find that the existence of a landscape of eternal inflation in this model provides us with a natural theory of initial conditions for the inflationary period in our vacuum. We demonstrate how these two effects work in a small corner of the landscape associated with the complex structure of the Calabi-Yau manifold P41,1,1,6,9 by numerically investigating the flux vacua of a reduced moduli space. This allows us to obtain the distribution of observable parameters for inflation in this mini-landscape directly from the fluxes.

Calculations of rate constants for the three-body recombination of H2 in the presence of H2

NASA Technical Reports Server (NTRS)

Schwenke, David W.

1988-01-01

A new global potential energy hypersurface for H2 + H2 is constructed and quasiclassical trajectory calculations performed using the resonance complex theory and energy transfer mechanism to estimate the rate of three body recombination over the temperature range 100 to 5000 K. The new potential is a faithful representation of ab initio electron structure calculations, is unchanged under the operation of exchanging H atoms, and reproduces the accurate H3 potential as one H atom is pulled away. Included in the fitting procedure are geometries expected to be important when one H2 is near or above the dissociation limit. The dynamics calculations explicitly include the motion of all four atoms and are performed efficiently using a vectorized variable-stepsize integrator. The predicted rate constants are approximately a factor of two smaller than experimental estimates over a broad temperature range.

Molecular aspects of the Eu3+/Eu2+ redox reaction at the interface between a molten salt and a metallic electrode

NASA Astrophysics Data System (ADS)

Pounds, Michael A.; Salanne, Mathieu; Madden, Paul A.

2015-09-01

We perform molecular dynamics simulations of a system consisting of Eu3+ and Eu2+ species dissolved in a high-temperature KCl electrolyte between two metallic electrodes. The interaction potential includes ion polarisation effects, and a constant electric potential is maintained within the electrodes by allowing the atomic charges to fluctuate in response to the environment. This setup allows us to study the electrochemical Eu3+/Eu2+ reaction in the framework of Marcus theory. Numerous studies have pointed to the highly structured nature of ionic liquids and molten salts close to solid surfaces which is not accounted for in the conventional mean-field description of this interface that underpins the theories of electrochemical reaction rates. Here we examine the influence on the kinetics of the charge-transfer event of the electrical potential across the electrode-electrolyte interface and on the effect of the presence of charged surface on the coordination structure and energetics of the ions in the region important for the charge-transfer event.

Breakdown of the single-exchange approximation in third-order symmetry-adapted perturbation theory.

PubMed

Lao, Ka Un; Herbert, John M

2012-03-22

We report third-order symmetry-adapted perturbation theory (SAPT) calculations for several dimers whose intermolecular interactions are dominated by induction. We demonstrate that the single-exchange approximation (SEA) employed to derive the third-order exchange-induction correction (E(exch-ind)((30))) fails to quench the attractive nature of the third-order induction (E(ind)((30))), leading to one-dimensional potential curves that become attractive rather than repulsive at short intermolecular separations. A scaling equation for (E(exch-ind)((30))), based on an exact formula for the first-order exchange correction, is introduced to approximate exchange effects beyond the SEA, and qualitatively correct potential energy curves that include third-order induction are thereby obtained. For induction-dominated systems, our results indicate that a "hybrid" SAPT approach, in which a dimer Hartree-Fock calculation is performed in order to obtain a correction for higher-order induction, is necessary not only to obtain quantitative binding energies but also to obtain qualitatively correct potential energy surfaces. These results underscore the need to develop higher-order exchange-induction formulas that go beyond the SEA. © 2012 American Chemical Society

A global reaction route mapping-based kinetic Monte Carlo algorithm

NASA Astrophysics Data System (ADS)

Mitchell, Izaac; Irle, Stephan; Page, Alister J.

2016-07-01

We propose a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. Starting from any given equilibrium state, this GRRM-KMC algorithm performs a one-step GRRM search to identify all surrounding transition states. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculated on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde and surface carbon diffusion on an iron nanoparticle. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding potential.

A global reaction route mapping-based kinetic Monte Carlo algorithm.

PubMed

Mitchell, Izaac; Irle, Stephan; Page, Alister J

2016-07-14

We propose a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. Starting from any given equilibrium state, this GRRM-KMC algorithm performs a one-step GRRM search to identify all surrounding transition states. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculated on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde and surface carbon diffusion on an iron nanoparticle. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding potential.

Voltage-induced switching of an antiferromagnetically ordered topological Dirac semimetal

NASA Astrophysics Data System (ADS)

Kim, Youngseok; Kang, Kisung; Schleife, André; Gilbert, Matthew J.

2018-04-01

An antiferromagnetic semimetal has been recently identified as a new member of topological semimetals that may host three-dimensional symmetry-protected Dirac fermions. A reorientation of the Néel vector may break the underlying symmetry and open a gap in the quasiparticle spectrum, inducing the (semi)metal-insulator transition. Here, we predict that such a transition may be controlled by manipulating the chemical potential location of the material. We perform both analytical and numerical analysis on the thermodynamic potential of the model Hamiltonian and find that the gapped spectrum is preferred when the chemical potential is located at the Dirac point. As the chemical potential deviates from the Dirac point, the system shows a possible transition from the gapped to the gapless phase and switches the corresponding Néel vector configuration. We perform density functional theory calculations to verify our analysis using a realistic material and discuss a two terminal transport measurement as a possible route to identify the voltage-induced switching of the Néel vector.

Network Theory: A Primer and Questions for Air Transportation Systems Applications

NASA Technical Reports Server (NTRS)

Holmes, Bruce J.

2004-01-01

A new understanding (with potential applications to air transportation systems) has emerged in the past five years in the scientific field of networks. This development emerges in large part because we now have a new laboratory for developing theories about complex networks: The Internet. The premise of this new understanding is that most complex networks of interest, both of nature and of human contrivance, exhibit a fundamentally different behavior than thought for over two hundred years under classical graph theory. Classical theory held that networks exhibited random behavior, characterized by normal, (e.g., Gaussian or Poisson) degree distributions of the connectivity between nodes by links. The new understanding turns this idea on its head: networks of interest exhibit scale-free (or small world) degree distributions of connectivity, characterized by power law distributions. The implications of scale-free behavior for air transportation systems include the potential that some behaviors of complex system architectures might be analyzed through relatively simple approximations of local elements of the system. For air transportation applications, this presentation proposes a framework for constructing topologies (architectures) that represent the relationships between mobility, flight operations, aircraft requirements, and airspace capacity, and the related externalities in airspace procedures and architectures. The proposed architectures or topologies may serve as a framework for posing comparative and combinative analyses of performance, cost, security, environmental, and related metrics.

Toward a Meta-Theory of Learning and Performance

ERIC Educational Resources Information Center

Russ-Eft, Darlene

2004-01-01

This purpose of this paper is to identify implications of various learning theories for workplace learning and performance and HRD. It begins with a review of various theoretical positions on learning including behaviorism, Gestalt theory, cognitive theory, schema theory, connectionist theory, social learning or behavior modeling, social…

Scalar-fluid interacting dark energy: Cosmological dynamics beyond the exponential potential

NASA Astrophysics Data System (ADS)

Dutta, Jibitesh; Khyllep, Wompherdeiki; Tamanini, Nicola

2017-01-01

We extend the dynamical systems analysis of scalar-fluid interacting dark energy models performed in C. G. Boehmer et al., Phys. Rev. D 91, 123002 (2015), 10.1103/PhysRevD.91.123002 by considering scalar field potentials beyond the exponential type. The properties and stability of critical points are examined using a combination of linear analysis, computational methods and advanced mathematical techniques, such as center manifold theory. We show that the interesting results obtained with an exponential potential can generally be recovered also for more complicated scalar field potentials. In particular, employing power law and hyperbolic potentials as examples, we find late time accelerated attractors, transitions from dark matter to dark energy domination with specific distinguishing features, and accelerated scaling solutions capable of solving the cosmic coincidence problem.

Turbine blade forced response prediction using FREPS

NASA Technical Reports Server (NTRS)

Murthy, Durbha, V.; Morel, Michael R.

1993-01-01

This paper describes a software system called FREPS (Forced REsponse Prediction System) that integrates structural dynamic, steady and unsteady aerodynamic analyses to efficiently predict the forced response dynamic stresses in axial flow turbomachinery blades due to aerodynamic and mechanical excitations. A flutter analysis capability is also incorporated into the system. The FREPS system performs aeroelastic analysis by modeling the motion of the blade in terms of its normal modes. The structural dynamic analysis is performed by a finite element code such as MSC/NASTRAN. The steady aerodynamic analysis is based on nonlinear potential theory and the unsteady aerodynamic analyses is based on the linearization of the non-uniform potential flow mean. The program description and presentation of the capabilities are reported herein. The effectiveness of the FREPS package is demonstrated on the High Pressure Oxygen Turbopump turbine of the Space Shuttle Main Engine. Both flutter and forced response analyses are performed and typical results are illustrated.

Active Enhancement of Slow Light Based on Plasmon-Induced Transparency with Gain Materials.

PubMed

Zhang, Zhaojian; Yang, Junbo; He, Xin; Han, Yunxin; Zhang, Jingjing; Huang, Jie; Chen, Dingbo; Xu, Siyu

2018-06-03

As a plasmonic analogue of electromagnetically induced transparency (EIT), plasmon-induced transparency (PIT) has drawn more attention due to its potential of realizing on-chip sensing, slow light and nonlinear effect enhancement. However, the performance of a plasmonic system is always limited by the metal ohmic loss. Here, we numerically report a PIT system with gain materials based on plasmonic metal-insulator-metal waveguide. The corresponding phenomenon can be theoretically analyzed by coupled mode theory (CMT). After filling gain material into a disk cavity, the system intrinsic loss can be compensated by external pump beam, and the PIT can be greatly fueled to achieve a dramatic enhancement of slow light performance. Finally, a double-channel enhanced slow light is introduced by adding a second gain disk cavity. This work paves way for a potential new high-performance slow light device, which can have significant applications for high-compact plasmonic circuits and optical communication.

Invertibility of retarded response functions for Laplace transformable potentials: Application to one-body reduced density matrix functional theory.

PubMed

Giesbertz, K J H

2015-08-07

A theorem for the invertibility of arbitrary response functions is presented under the following conditions: the time dependence of the potentials should be Laplace transformable and the initial state should be a ground state, though it might be degenerate. This theorem provides a rigorous foundation for all density-functional-like theories in the time-dependent linear response regime. Especially for time-dependent one-body reduced density matrix (1RDM) functional theory, this is an important step forward, since a solid foundation has currently been lacking. The theorem is equally valid for static response functions in the non-degenerate case, so can be used to characterize the uniqueness of the potential in the ground state version of the corresponding density-functional-like theory. Such a classification of the uniqueness of the non-local potential in ground state 1RDM functional theory has been lacking for decades. With the aid of presented invertibility theorem presented here, a complete classification of the non-uniqueness of the non-local potential in 1RDM functional theory can be given for the first time.

The Hartree product and the description of local and global quantities in atomic systems: A study within Kohn-Sham theory

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

Garza, Jorge; Nichols, Jeffrey A.; Dixon, David A.

2000-01-15

The Hartree product is analyzed in the context of Kohn-Sham theory. The differential equations that emerge from this theory are solved with the optimized effective potential using the Krieger, Li, and Iafrate approximation, in order to get a local potential as required by the ordinary Kohn-Sham procedure. Because the diagonal terms of the exact exchange energy are included in Hartree theory, it is self-interaction free and the exchange potential has the proper asymptotic behavior. We have examined the impact of this correct asymptotic behavior on local and global properties using this simple model to approximate the exchange energy. Local quantities,more » such as the exchange potential and the average local electrostatic potential are used to examine whether the shell structure in an atom is revealed by this theory. Global quantities, such as the highest occupied orbital energy (related to the ionization potential) and the exchange energy are also calculated. These quantities are contrasted with those obtained from calculations with the local density approximation, the generalized gradient approximation, and the self-interaction correction approach proposed by Perdew and Zunger. We conclude that the main characteristics in an atomic system are preserved with the Hartree theory. In particular, the behavior of the exchange potential obtained in this theory is similar to those obtained within other Kohn-Sham approximations. (c) 2000 American Institute of Physics.« less

Development summary of a sympathetic discharge CO2 laser for lidar use

NASA Technical Reports Server (NTRS)

Jaenisch, Holger M.; Johnson, R. Barry

1991-01-01

A commercial pulsed sympathetic discharge laser has been characterized and modified for use as a potential lidar. This report summarizes the initial findings and modifications made to the baseline system. The new laser performance is then checked with theory and operational results are presented. The laser has inherent mode instability and high chirp. Several solutions were tried and their results are presented.

Using Potential Performance Theory to Assess How to Increase Student Consistency in Taking Exams

ERIC Educational Resources Information Center

Rice, Stephen; Trafimow, David; Kraemer, Keegan

2012-01-01

It has been a concern among educators and academics that U.S. students suffer from a lack of knowledge about the world around them. This is reflected in low history scores, particularly in world history. The common explanation for this is that there is some systematic deficiency in American students, in that they either do not know the material or…

Loop corrections in double field theory: non-trivial dilaton potentials

NASA Astrophysics Data System (ADS)

Lv, Songlin; Wu, Houwen; Yang, Haitang

2014-10-01

It is believed that the invariance of the generalised diffeomorphisms prevents any non-trivial dilaton potential from double field theory. It is therefore difficult to include loop corrections in the formalism. We show that by redefining a non-local dilaton field, under strong constraint which is necessary to preserve the gauge invariance of double field theory, the theory does permit non-constant dilaton potentials and loop corrections. If the fields have dependence on only one single coordinate, the non-local dilaton is identical to the ordinary one with an additive constant.

Kinetic theory for strongly coupled Coulomb systems

NASA Astrophysics Data System (ADS)

Dufty, James; Wrighton, Jeffrey

2018-01-01

The calculation of dynamical properties for matter under extreme conditions is a challenging task. The popular Kubo-Greenwood model exploits elements from equilibrium density-functional theory (DFT) that allow a detailed treatment of electron correlations, but its origin is largely phenomenological; traditional kinetic theories have a more secure foundation but are limited to weak ion-electron interactions. The objective here is to show how a combination of the two evolves naturally from the short-time limit for the generator of the effective single-electron dynamics governing time correlation functions without such limitations. This provides a theoretical context for the current DFT-related approach, the Kubo-Greenwood model, while showing the nature of its corrections. The method is to calculate the short-time dynamics in the single-electron subspace for a given configuration of the ions. This differs from the usual kinetic theory approach in which an average over the ions is performed as well. In this way the effective ion-electron interaction includes strong Coulomb coupling and is shown to be determined from DFT. The correlation functions have the form of the random-phase approximation for an inhomogeneous system but with renormalized ion-electron and electron-electron potentials. The dynamic structure function, density response function, and electrical conductivity are calculated as examples. The static local field corrections in the dielectric function are identified in this way. The current analysis is limited to semiclassical electrons (quantum statistical potentials), so important quantum conditions are excluded. However, a quantization of the kinetic theory is identified for broader application while awaiting its detailed derivation.

Two-parameter partially correlated ground-state electron density of some light spherical atoms from Hartree-Fock theory with nonintegral nuclear charge

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

Cordero, Nicolas A.; March, Norman H.; Alonso, Julio A.

2007-05-15

Partially correlated ground-state electron densities for some spherical light atoms are calculated, into which nonrelativistic ionization potentials represent essential input data. The nuclear cusp condition of Kato is satisfied precisely. The basic theoretical starting point, however, is Hartree-Fock (HF) theory for the N electrons under consideration but with nonintegral nuclear charge Z{sup '} slightly different from the atomic number Z (=N). This HF density is scaled with a parameter {lambda}, near to unity, to preserve normalization. Finally, some tests are performed on the densities for the atoms Ne and Ar, as well as for Be and Mg.

Numerical and Experimental Study on Hydrodynamic Performance of A Novel Semi-Submersible Concept

NASA Astrophysics Data System (ADS)

Gao, Song; Tao, Long-bin; Kou, Yu-feng; Lu, Chao; Sun, Jiang-long

2018-04-01

Multiple Column Platform (MCP) semi-submersible is a newly proposed concept, which differs from the conventional semi-submersibles, featuring centre column and middle pontoon. It is paramount to ensure its structural reliability and safe operation at sea, and a rigorous investigation is conducted to examine the hydrodynamic and structural performance for the novel structure concept. In this paper, the numerical and experimental studies on the hydrodynamic performance of MCP are performed. Numerical simulations are conducted in both the frequency and time domains based on 3D potential theory. The numerical models are validated by experimental measurements obtained from extensive sets of model tests under both regular wave and irregular wave conditions. Moreover, a comparative study on MCP and two conventional semi-submersibles are carried out using numerical simulation. Specifically, the hydrodynamic characteristics, including hydrodynamic coefficients, natural periods and motion response amplitude operators (RAOs), mooring line tension are fully examined. The present study proves the feasibility of the novel MCP and demonstrates the potential possibility of optimization in the future study.

Case II: Conflict recognition--the case of the misdirected faculty.

PubMed

Hoelscher, Diane C; Comer, Robert W

2002-04-01

Early recognition is fundamental to managing conflict. Successful leaders rely upon their ability to recognize conflict before it escalates into crisis. This article reviews the signs and sources of conflict along with related management theories. Conflict management includes understanding the sources and types of conflict as well as the impact potential; in the case presented, the leaders were unaware of conflict. Dr. Forester, the faculty member "in the middle," was in a precarious position. Her performance evaluation reflected unacceptable accomplishments. However, her self-assessment, based on the hiring agreement, was successful. Her requests for guidance and clarification were unproductive. What does she do now? The management theories that apply to the case of "the misdirected faculty" include analysis and discussion of communication, feedback, and expectancy theory. Action alternatives are presented to explore some of the options available to stimulate discussion and to provide readers with an eclectic approach to applying a case analysis.

Relatedness in spatially structured populations with empty sites: An approach based on spatial moment equations.

PubMed

Lion, Sébastien

2009-09-07

Taking into account the interplay between spatial ecological dynamics and selection is a major challenge in evolutionary ecology. Although inclusive fitness theory has proven to be a very useful tool to unravel the interactions between spatial genetic structuring and selection, applications of the theory usually rely on simplifying demographic assumptions. In this paper, I attempt to bridge the gap between spatial demographic models and kin selection models by providing a method to compute approximations for relatedness coefficients in a spatial model with empty sites. Using spatial moment equations, I provide an approximation of nearest-neighbour relatedness on random regular networks, and show that this approximation performs much better than the ordinary pair approximation. I discuss the connection between the relatedness coefficients I define and those used in population genetics, and sketch some potential extensions of the theory.

Hard sphere perturbation theory for fluids with soft-repulsive-core potentials

NASA Astrophysics Data System (ADS)

Ben-Amotz, Dor; Stell, George

2004-03-01

The thermodynamic properties of fluids with very soft repulsive-core potentials, resembling those of some liquid metals, are predicted with unprecedented accuracy using a new first-order thermodynamic perturbation theory. This theory is an extension of Mansoori-Canfield/Rasaiah-Stell (MCRS) perturbation theory, obtained by including a configuration integral correction recently identified by Mon, who evaluated it by computer simulation. In this work we derive an analytic expression for Mon's correction in terms of the radial distribution function of the soft-core fluid, g0(r), approximated using Lado's self-consistent extension of Weeks-Chandler-Andersen (WCA) theory. Comparisons with WCA and MCRS predictions show that our new extended-MCRS theory outperforms other first-order theories when applied to fluids with very soft inverse-power potentials (n⩽6), and predicts free energies that are within 0.3kT of simulation results up to the fluid freezing point.

Too Good to be True? Ideomotor Theory from a Computational Perspective

PubMed Central

Herbort, Oliver; Butz, Martin V.

2012-01-01

In recent years, Ideomotor Theory has regained widespread attention and sparked the development of a number of theories on goal-directed behavior and learning. However, there are two issues with previous studies’ use of Ideomotor Theory. Although Ideomotor Theory is seen as very general, it is often studied in settings that are considerably more simplistic than most natural situations. Moreover, Ideomotor Theory’s claim that effect anticipations directly trigger actions and that action-effect learning is based on the formation of direct action-effect associations is hard to address empirically. We address these points from a computational perspective. A simple computational model of Ideomotor Theory was tested in tasks with different degrees of complexity. The model evaluation showed that Ideomotor Theory is a computationally feasible approach for understanding efficient action-effect learning for goal-directed behavior if the following preconditions are met: (1) The range of potential actions and effects has to be restricted. (2) Effects have to follow actions within a short time window. (3) Actions have to be simple and may not require sequencing. The first two preconditions also limit human performance and thus support Ideomotor Theory. The last precondition can be circumvented by extending the model with more complex, indirect action generation processes. In conclusion, we suggest that Ideomotor Theory offers a comprehensive framework to understand action-effect learning. However, we also suggest that additional processes may mediate the conversion of effect anticipations into actions in many situations. PMID:23162524

Attractor cosmology from nonminimally coupled gravity

NASA Astrophysics Data System (ADS)

Odintsov, S. D.; Oikonomou, V. K.

2018-03-01

By using a bottom-up reconstruction technique for nonminimally coupled scalar-tensor theories, we realize the Einstein frame attractor cosmologies in the Ω (ϕ )-Jordan frame. For our approach, what is needed for the reconstruction method to work is the functional form of the nonminimal coupling Ω (ϕ ) and of the scalar-to-tensor ratio, and also the assumption of the slow-roll inflation in the Ω (ϕ )-Jordan frame. By appropriately choosing the scalar-to-tensor ratio, we demonstrate that the observational indices of the attractor cosmologies can be realized directly in the Ω (ϕ )-Jordan frame. We investigate the special conditions that are required to hold true in for this realization to occur, and we provide the analytic form of the potential in the Ω (ϕ )-Jordan frame. Also, by performing a conformal transformation, we find the corresponding Einstein frame canonical scalar-tensor theory, and we calculate in detail the corresponding observational indices. The result indicates that although the spectral index of the primordial curvature perturbations is the same in the Jordan and Einstein frames, at leading order in the e -foldings number, the scalar-to-tensor ratio differs. We discuss the possible reasons behind this discrepancy, and we argue that the difference is due to some approximation we performed to the functional form of the potential in the Einstein frame, in order to obtain analytical results, and also due to the difference in the definition of the e -foldings number in the two frames, which is also pointed out in the related literature. Finally, we find the F (R ) gravity corresponding to the Einstein frame canonical scalar-tensor theory.

Implementation of Patient Decision Support Interventions in Primary Care: The Role of Relational Coordination.

PubMed

Tietbohl, Caroline K; Rendle, Katharine A S; Halley, Meghan C; May, Suepattra G; Lin, Grace A; Frosch, Dominick L

2015-11-01

The benefits of patient decision support interventions (DESIs) have been well documented. However, DESIs remain difficult to incorporate into clinical practice. Relational coordination (RC) has been shown to improve performance and quality of care in health care settings. This study aims to demonstrate how applying RC theory to DESI implementation could elucidate underlying issues limiting widespread uptake. Five primary care clinics in Northern California participated in a DESI implementation project. We used a deductive thematic approach guided by behaviors outlined in RC theory to analyze qualitative data collected from ethnographic field notes documenting the implementation process and focus groups with health care professionals. We then systematically compared the qualitative findings with quantitative DESI distribution data. Based on DESI distribution rates, clinics were placed into 3 performance categories: high, middle, and low. Qualitative data illustrated how each clinic's performance related to RC behaviors. Consistent with RC theory, the high-performing clinic exhibited frequent, timely, and accurate communication and positive working relationships. The 3 middle-performing clinics exhibited high-quality communication within physician-staff teams but limited communication regarding DESI implementation across the clinic. The lowest-performing clinic was characterized by contentious relationships and inadequate communication. Limitations of the study include nonrandom selection of clinics and limited geographic diversity. In addition, ethnographic data collected documented only DESI implementation practices and not larger staff interactions contributing to RC. These findings suggest that a high level of RC within clinical settings may be a key component and facilitator of successful DESI implementation. Future attempts to integrate DESIs into clinical practice should consider incorporating interventions designed to increase positive RC behaviors as a potential means to improve uptake. © The Author(s) 2015.

Rare-gas impurities in alkali metals: Relation to optical absorption

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

Meltzer, D.E.; Pinski, F.J.; Stocks, G.M.

1988-04-15

An investigation of the nature of rare-gas impurity potentials in alkali metals is performed. Results of calculations based on simple models are presented, which suggest the possibility of resonance phenomena. These could lead to widely varying values for the exponents which describe the shape of the optical-absorption spectrum at threshold in the Mahan--Nozieres--de Dominicis theory. Detailed numerical calculations are then performed with the Korringa-Kohn-Rostoker coherent-potential-approximation method. The results of these highly realistic calculations show no evidence for the resonance phenomena, and lead to predictions for the shape of the spectra which are in contradiction to observations. Absorption and emission spectramore » are calculated for two of the systems studied, and their relation to experimental data is discussed.« less

London equation for monodromy inflation

NASA Astrophysics Data System (ADS)

Kaloper, Nemanja; Lawrence, Albion

2017-03-01

We focus on the massive gauge theory formulation of axion monodromy inflation. We argue that a gauge symmetry hidden in these models is the key mechanism protecting inflation from dangerous field theory and quantum gravity corrections. The effective theory of large-field inflation is dual to a massive U (1 ) 4-form gauge theory, which is similar to a massive gauge theory description of superconductivity. The gauge theory explicitly realizes the old Julia-Toulouse proposal for a low-energy description of a gauge theory in a defect condensate. While we work mostly with the example of quadratic axion potential induced by flux monodromy, we discuss how other types of potentials can arise from the inclusion of gauge-invariant corrections to the theory.

Telluric currents: A meeting of theory and observation

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

Boteler, D.H.; Seager, W.H.

Pipe-to-soil (P/S) potential variations resulting from telluric currents have been observed on pipelines in many locations. However, it has never teen clear which parts of a pipeline will experience the worst effects. Two studies were conducted to answer this question. Distributed-source transmission line (DSTL) theory was applied to the problem of modeling geomagnetic induction in pipelines. This theory predicted that the largest P/S potential variations would occur at the ends of the pipeline. The theory also predicted that large P/S potential variations, of opposite sign, should occur on either side of an insulating flange. Independently, an observation program was conductedmore » to determine the change in telluric current P/S potential variations and to design counteractive measures along a pipeline in northern Canada. Observations showed that the amplitude of P/S potential fluctuations had maxima at the northern and southern ends of the pipeline. A further set of recordings around an insulating flange showed large P/S potential variations, of opposite sign, on either side of the flange. Agreement between the observations and theoretical predictions was remarkable. While the observations confirmed the theory, the theory explains how P/S potential variations are produced by telluric currents and provides the basis for design of cathodic protection systems for pipelines that can counteract any adverse telluric effects.« less

Propulsion of a fin whale (Balaenoptera physalus): why the fin whale is a fast swimmer.

PubMed

Bose, N; Lien, J

1989-07-22

Measurements of an immature fin whale (Balaenoptera physalus), which died as a result of entrapment in fishing gear near Frenchmans Cove, Newfoundland (47 degrees 9' N, 55 degrees 25' W), were made to obtain estimates of volume and surface area of the animal. Detailed measurements of the flukes, both planform and sections, were also obtained. A strip theory was developed to calculate the hydrodynamic performance of the whale's flukes as an oscillating propeller. This method is based on linear, two-dimensional, small-amplitude, unsteady hydrofoil theory with correction factors used to account for the effects of finite span and finite amplitude motion. These correction factors were developed from theoretical results of large-amplitude heaving motion and unsteady lifting-surface theory. A model that makes an estimate of the effects of viscous flow on propeller performance was superimposed on the potential-flow results. This model estimates the drag of the hydrofoil sections by assuming that the drag is similar to that of a hydrofoil section in steady flow. The performance characteristics of the flukes of the fin whale were estimated by using this method. The effects of the different correction factors, and of the frictional drag of the fluke sections, are emphasized. Frictional effects in particular were found to reduce the hydrodynamic efficiency of the flukes significantly. The results are discussed and compared with the known characteristics of fin-whale swimming.

Symptomatology and social inference: a theory of mind study of schizophrenia and psychotic affective disorder.

PubMed

Marjoram, Dominic; Gardner, Clare; Burns, Jonathan; Miller, Patrick; Lawrie, Stephen M; Johnstone, Eve C

2005-11-01

There is evidence that certain patients with schizophrenia have deficits in theory of mind (ToM) capabilities. It is, however, unclear whether these are symptom or diagnosis-specific. A ToM hinting task was given to 15 patients with a DSM-IV diagnosis of schizophrenia, 15 patients with affective disorder and 15 healthy controls. Severity of the current psychopathology was measured using the Krawiecka standardised scale of psychotic symptoms (Krawiecka, Goldberg, & Vaughan, 1977); IQ was estimated via the Ammons and Ammons Quick Test (Ammons & Ammons, 1962). The group with schizophrenia performed significantly worse than the affective and control groups. Poor performance on the hinting task was found to be significantly related to the presence of positive symptoms (instead of negative ones) and specifically related to delusions and hallucinations. These findings remained when covariance for potentially confounding variables was applied. Individuals with high levels of delusions and hallucinations performed significantly worse on this ToM task, regardless of diagnosis, implying ToM impairment is not exclusive to schizophrenia but is evident in other forms of psychosis. Between-group analyses showed the schizophrenia group had a significantly poorer performance on this task than the others.

Theory of mind ability in high socially anxious individuals.

PubMed

Lenton-Brym, Ariella P; Moscovitch, David A; Vidovic, Vanja; Nilsen, Elizabeth; Friedman, Ori

2018-06-25

Research has demonstrated an association between social anxiety and impaired Theory of Mind (ToM). We assess whether ToM deficits occur even at a subclinical level of social anxiety and whether group differences in ToM performance are consistent with interpretation bias. We also explore potential reasons as to why socially anxious individuals may perform differently on ToM tasks. Undergraduate participants high (HSA; n = 78) and low (LSA; n = 35) in social anxiety completed a task of ToM decoding, the Reading the Mind in the Eyes (MIE), a task of ToM reasoning, the Movie for the Assessment of Social Cognition (MASC), and a post-task questionnaire about their experience completing the MASC. HSAs performed marginally worse than LSAs on the MIE on neutrally valenced trials, and their pattern of errors may be consistent with a negative interpretation bias. HSAs and LSAs did not differ overall in performance on the MASC, though HSAs reported experiencing more confusion and distress than LSAs during the task, and this distress was associated with more MASC errors for HSA participants only. These results provide insight into the nature of ToM ability in socially anxious individuals and highlight important avenues for future research.

Implementation of a real option in a sustainable supply chain: an empirical study of alkaline battery recycling

NASA Astrophysics Data System (ADS)

Cucchiella, Federica; D'Adamo, Idiano; Gastaldi, Massimo; Lenny Koh, S. C.

2014-06-01

Green supply chain management (GSCM) has emerged as a key approach for enterprises seeking to become environmentally sustainable. This paper aims to evaluate and describe the advantages of a GSCM approach by analysing practices and performance consequences in the battery recycling sector. It seeks to integrate works in supply chain management (SCM), environmental management, performance management and real option (RO) theory into one framework. In particular, life cycle assessment (LCA) is applied to evaluate the environmental impact of a battery recycling plant project, and life cycle costing (LCC) is applied to evaluate its economic impact. Firms, also understanding the relevance of GSCM, have often avoided applying the green principles because of the elevated costs that such management involved. Such costs could also seem superior to the potential advantages since standard performance measurement systems are internally and business focused; for these reasons, we consider all the possible value deriving also by uncertainty associated to a green project using the RO theory. This work is one of the few and pioneering efforts to investigate GSCM practices in the battery recycling sector.

Nano-scale mass sensor based on the vibration analysis of a magneto-electro-elastic nanoplate resting on a visco-Pasternak substrate

NASA Astrophysics Data System (ADS)

Khanmirza, E.; Jamalpoor, A.; Kiani, A.

2017-10-01

In this paper, a magneto-electro-elastic nanoplate resting on a visco-Pasternak medium with added concentrated nanoparticles is presented as a mass nanosensor according to the vibration analysis. The MEE nanoplate is supposed to be subject to external electric voltage and magnetic potential. In order to take into account the size effect on the sensitivity of the sensor, the nonlocal elasticity theory in conjunction with the Kirchhoff plate theory is applied. Partial differential equations are derived by implementing Hamilton's variational principle. Equilibrium equations were solved analytically to determine an explicit closed-form statement for both the damped frequency shift and the relative damped frequency shift using Navier's approach. A genetic algorithm (GA) is employed to achieve the optimal added nanoparticle location to gain the most sensitivity performance of the nanosensor. Numerical studies are performed to illustrate the variation of the sensitivity property corresponding to various values of the number of attached nanoparticles, the mass of each nanoparticle, the nonlocal parameter, external electric voltage and magnetic potential, the aspect ratio, and visco-Pasternak parameters. Some numerical outcomes of this paper show that the minimum value of the damped frequency shift occurs for a certain value of the length-to-thickness ratio. Also, it is shown that the external magnetic and external electric potentials have a different effect on the sensitivity property. It is anticipated that the results reported in this work can be considered as a benchmark in future micro-structures issues.

How to Improve Adolescent Stress Responses: Insights from an Integration of Implicit Theories and Biopsychosocial Models

PubMed Central

Yeager, David S.; Lee, Hae Yeon; Jamieson, Jeremy

2016-01-01

This research integrated implicit theories and the biopsychosocial (BPS) model of challenge and threat, hypothesizing that adolescents would be more likely to conclude that they have the resources to meet the demands of an evaluative social situation when they were taught a belief that people have the potential to change their socially-relevant traits. Study 1 (N=60) randomly assigned high school adolescents to an incremental theory of personality or control condition, and then administered a standardized social stress task. Relative to controls, incremental theory participants exhibited improved stress appraisals, more adaptive neuroendocrine and cardiovascular responses (lower salivary cortisol, reduced vascular resistance, higher stroke volume, and more rapid return to homeostasis after stress offset), and better performance outcomes. Study 2 (N=205) used a daily diary intervention study to test high school adolescents’ stress reactivity outside the laboratory. Threat appraisals (days 5–9 post-intervention) and neuroendocrine responses (cortisol and DHEA-S; days 8–9 post-intervention only) were untethered from the intensity of daily stressors when adolescents received the incremental theory of personality intervention. The intervention also improved grades over freshman year. These findings offer new avenues for improving theories of adolescent stress and coping. PMID:27324267

A theory-based curriculum design for remediation of residents' communication skills.

PubMed

Leung, Fok-Han; Martin, Dawn; Batty, Helen

2009-12-01

Residents requiring remediation are often deficient in communication skills, namely clinical interviewing skills. Residents have to digest large amounts of knowledge, and then apply it in a clinical interview. The patient-centered approach, as demonstrated in the Calgary-Cambridge model and Martin's Map, can be difficult to teach. Before implementing a remediation curriculum, the theoretical educational underpinnings must be sound; curriculum evaluation is often expensive. Before establishing metrics for curriculum evaluation, a starting point is to perform a mental experiment to test theoretical adherence. This article describes an experiential remedial curriculum for communication skills. Educational theories of Kolb, Knowles, Bandura, and Bloom are used to design the curriculum into theory-based design components. Kolb's experiential cycle models the natural sequence of experiencing, teaching, and learning interviewing skills. A curriculum structured around this cycle has multiple intercalations with the above educational theories. The design is strengthened by appropriately timed use of education strategies such as learning contracts, taped interviews, simulations, structured reflection, and teacher role modeling. Importantly, it also models the form of the clinical interview format desired. Through understanding and application of contemporary educational theories, a program to remediate interviewing skills can increase its potential for success.

Community Service-Learning and Cultural-Historical Activity Theory

ERIC Educational Resources Information Center

Taylor, Alison

2014-01-01

This paper explores the potential of cultural-historical activity theory (CHAT), to provide new insights into community service-learning (CSL) in higher education. While CSL literature acknowledges the influences of John Dewey and Paolo Freire, discussion of the potential contribution of cultural-historical activity theory, rooted in the work of…

An experimental and theoretical analysis of the aerodynamic characteristics of a biplane-winglet configuration. M.D. Thesis

NASA Technical Reports Server (NTRS)

Gall, P. D.

1984-01-01

Improving the aerodynamic characteristics of an airplane with respect to maximizing lift and minimizing induced and parasite drag are of primary importance in designing lighter, faster, and more efficient aircraft. Previous research has shown that a properly designed biplane wing system can perform superiorly to an equivalent monoplane system with regard to maximizing the lift-to-drag ratio and efficiency factor. Biplanes offer several potential advantages over equivalent monoplanes, such as a 60-percent reduction in weight, greater structural integrity, and increased roll response. The purpose of this research is to examine, both theoretically and experimentally, the possibility of further improving the aerodynamic characteristics of the biplanes configuration by adding winglets. Theoretical predictions were carried out utilizing vortex-lattice theory, which is a numerical method based on potential flow theory. Experimental data were obtained by testing a model in the Pennsylvania State University's subsonic wind tunnel at a Reynolds number of 510,000. The results showed that the addition of winglets improved the performance of the biplane with respect to increasing the lift-curve slope, increasing the maximum lift coefficient, increasing the efficiency factor, and decreasing the induced drag. A listing of the program is included in the Appendix.

Time dependent-density functional theory (TD-DFT) and experimental studies of UV-Visible spectra and cyclic voltammetry for Cu(II) complex with Et2DTC

NASA Astrophysics Data System (ADS)

Valle, Eliana Maira A.; Maltarollo, Vinicius Gonçalves; Almeida, Michell O.; Honorio, Kathia Maria; dos Santos, Mauro Coelho; Cerchiaro, Giselle

2018-04-01

In this work, we studied the complexation mode between copper(II) ion and the specific ligand investigated as carriers of metals though biological membranes, diethyldithiocarbamate (Et2DTC). It is important to understand how this occurs because it is an important intracellular chelator with potential therapeutic applications. Theoretical and experimental UV visible studies were performed to investigate the complexation mode between copper and the ligand. Electrochemical studies were also performed to complement the spectroscopic analyses. According to the theoretical calculations, using TD-DFT (Time dependent density functional theory), with B3LYP functional and DGDVZP basis set, implemented in Gaussian 03 package, it was observed that the formation of the complex [Cu(Et2DTC)2] is favorable with higher electron density over the sulfur atoms of the ligand. UV/Vis spectra have a charge transfer band at 450 nm, with the DMSO-d6 band shift from 800 to 650 nm. The electrochemical experiments showed the formation of a new redox process, referring to the complex, where the reduction peak potential of copper is displaced to less positive region. Therefore, the results obtained from this study give important insights on possible mechanisms involved in several biological processes related to the studied system.

Large-scale atomistic simulations of helium-3 bubble growth in complex palladium alloys

DOE PAGES

Hale, Lucas M.; Zimmerman, Jonathan A.; Wong, Bryan M.

2016-05-18

Palladium is an attractive material for hydrogen and hydrogen-isotope storage applications due to its properties of large storage density and high diffusion of lattice hydrogen. When considering tritium storage, the material’s structural and mechanical integrity is threatened by both the embrittlement effect of hydrogen and the creation and evolution of additional crystal defects (e.g., dislocations, stacking faults) caused by the formation and growth of helium-3 bubbles. Using recently developed inter-atomic potentials for the palladium-silver-hydrogen system, we perform large-scale atomistic simulations to examine the defect-mediated mechanisms that govern helium bubble growth. Our simulations show the evolution of a distribution of materialmore » defects, and we compare the material behavior displayed with expectations from experiment and theory. In conclusion, we also present density functional theory calculations to characterize ideal tensile and shear strengths for these materials, which enable the understanding of how and why our developed potentials either meet or confound these expectations.« less

Acoustic bubble dynamics in a microvessel surrounded by elastic material

NASA Astrophysics Data System (ADS)

Wang, S. P.; Wang, Q. X.; Leppinen, D. M.; Zhang, A. M.; Liu, Y. L.

2018-01-01

This paper is concerned with microbubble dynamics in a blood vessel surrounded by elastic tissue subject to ultrasound, which are associated with important applications in medical ultrasonics. Both the blood flow inside the vessel and the tissue flow external to the vessel are modeled using the potential flow theory coupled with the boundary element method. The elasticity of tissue is modeled through the inclusion of a pressure term in the dynamic boundary condition at the interface between the two fluids. Weakly viscous effects are considered using viscous potential flow theory. The numerical model is validated by comparison with the theoretical results of the Rayleigh-Plesset equation for spherical bubbles, the numerical results for acoustic bubbles in an unbounded flow, and the experimental images for a spark generated bubble in a rigid circular cylinder. Numerical analyses are then performed for the bubble oscillation, jet formation and penetration through the bubble, and the deformation of the vessel wall in terms of the ultrasound amplitude and the vessel radius.

The COREL and W12SC3 computer programs for supersonic wing design and analysis

NASA Technical Reports Server (NTRS)

Mason, W. H.; Rosen, B. S.

1983-01-01

Two computer codes useful in the supersonic aerodynamic design of wings, including the supersonic maneuver case are described. The nonlinear full potential equation COREL code performs an analysis of a spanwise section of the wing in the crossflow plane by assuming conical flow over the section. A subsequent approximate correction to the solution can be made in order to account for nonconical effects. In COREL, the flow-field is assumed to be irrotional (Mach numbers normal to shock waves less than about 1.3) and the full potential equation is solved to obtain detailed results for the leading edge expansion, supercritical crossflow, and any crossflow shockwaves. W12SC3 is a linear theory panel method which combines and extends elements of several of Woodward's codes, with emphasis on fighter applications. After a brief review of the aerodynamic theory used by each method, the use of the codes is illustrated with several examples, detailed input instructions and a sample case.

Teaching About "Brain and Learning" in High School Biology Classes: Effects on Teachers' Knowledge and Students' Theory of Intelligence.

PubMed

Dekker, Sanne; Jolles, Jelle

2015-01-01

This study evaluated a new teaching module about "Brain and Learning" using a controlled design. The module was implemented in high school biology classes and comprised three lessons: (1) brain processes underlying learning; (2) neuropsychological development during adolescence; and (3) lifestyle factors that influence learning performance. Participants were 32 biology teachers who were interested in "Brain and Learning" and 1241 students in grades 8-9. Teachers' knowledge and students' beliefs about learning potential were examined using online questionnaires. Results indicated that before intervention, biology teachers were significantly less familiar with how the brain functions and develops than with its structure and with basic neuroscientific concepts (46 vs. 75% correct answers). After intervention, teachers' knowledge of "Brain and Learning" had significantly increased (64%), and more students believed that intelligence is malleable (incremental theory). This emphasizes the potential value of a short teaching module, both for improving biology teachers' insights into "Brain and Learning," and for changing students' beliefs about intelligence.

Communication: Understanding molecular representations in machine learning: The role of uniqueness and target similarity

NASA Astrophysics Data System (ADS)

Huang, Bing; von Lilienfeld, O. Anatole

2016-10-01

The predictive accuracy of Machine Learning (ML) models of molecular properties depends on the choice of the molecular representation. Inspired by the postulates of quantum mechanics, we introduce a hierarchy of representations which meet uniqueness and target similarity criteria. To systematically control target similarity, we simply rely on interatomic many body expansions, as implemented in universal force-fields, including Bonding, Angular (BA), and higher order terms. Addition of higher order contributions systematically increases similarity to the true potential energy and predictive accuracy of the resulting ML models. We report numerical evidence for the performance of BAML models trained on molecular properties pre-calculated at electron-correlated and density functional theory level of theory for thousands of small organic molecules. Properties studied include enthalpies and free energies of atomization, heat capacity, zero-point vibrational energies, dipole-moment, polarizability, HOMO/LUMO energies and gap, ionization potential, electron affinity, and electronic excitations. After training, BAML predicts energies or electronic properties of out-of-sample molecules with unprecedented accuracy and speed.

Microscopically based energy density functionals for nuclei using the density matrix expansion. II. Full optimization and validation

NASA Astrophysics Data System (ADS)

Navarro Pérez, R.; Schunck, N.; Dyhdalo, A.; Furnstahl, R. J.; Bogner, S. K.

2018-05-01

Background: Energy density functional methods provide a generic framework to compute properties of atomic nuclei starting from models of nuclear potentials and the rules of quantum mechanics. Until now, the overwhelming majority of functionals have been constructed either from empirical nuclear potentials such as the Skyrme or Gogny forces, or from systematic gradient-like expansions in the spirit of the density functional theory for atoms. Purpose: We seek to obtain a usable form of the nuclear energy density functional that is rooted in the modern theory of nuclear forces. We thus consider a functional obtained from the density matrix expansion of local nuclear potentials from chiral effective field theory. We propose a parametrization of this functional carefully calibrated and validated on selected ground-state properties that is suitable for large-scale calculations of nuclear properties. Methods: Our energy functional comprises two main components. The first component is a non-local functional of the density and corresponds to the direct part (Hartree term) of the expectation value of local chiral potentials on a Slater determinant. Contributions to the mean field and the energy of this term are computed by expanding the spatial, finite-range components of the chiral potential onto Gaussian functions. The second component is a local functional of the density and is obtained by applying the density matrix expansion to the exchange part (Fock term) of the expectation value of the local chiral potential. We apply the UNEDF2 optimization protocol to determine the coupling constants of this energy functional. Results: We obtain a set of microscopically constrained functionals for local chiral potentials from leading order up to next-to-next-to-leading order with and without three-body forces and contributions from Δ excitations. These functionals are validated on the calculation of nuclear and neutron matter, nuclear mass tables, single-particle shell structure in closed-shell nuclei, and the fission barrier of 240Pu. Quantitatively, they perform noticeably better than the more phenomenological Skyrme functionals. Conclusions: The inclusion of higher-order terms in the chiral perturbation expansion seems to produce a systematic improvement in predicting nuclear binding energies while the impact on other observables is not really significant. This result is especially promising since all the fits have been performed at the single-reference level of the energy density functional approach, where important collective correlations such as center-of-mass correction, rotational correction, or zero-point vibrational energies have not been taken into account yet.

Applications of potential theory computations to transonic aeroelasticity

NASA Technical Reports Server (NTRS)

Edwards, J. W.

1986-01-01

Unsteady aerodynamic and aeroelastic stability calculations based upon transonic small disturbance (TSD) potential theory are presented. Results from the two-dimensional XTRAN2L code and the three-dimensional XTRAN3S code are compared with experiment to demonstrate the ability of TSD codes to treat transonic effects. The necessity of nonisentropic corrections to transonic potential theory is demonstrated. Dynamic computational effects resulting from the choice of grid and boundary conditions are illustrated. Unsteady airloads for a number of parameter variations including airfoil shape and thickness, Mach number, frequency, and amplitude are given. Finally, samples of transonic aeroelastic calculations are given. A key observation is the extent to which unsteady transonic airloads calculated by inviscid potential theory may be treated in a locally linear manner.

First-principles study of low Miller index Ni3S2 surfaces in hydrotreating conditions.

PubMed

Aray, Yosslen; Vega, David; Rodriguez, Jesus; Vidal, Alba B; Grillo, Maria Elena; Coll, Santiago

2009-03-12

Density functional theory (DFT) calculations combined with surface thermodynamic arguments and the Gibbs-Curie-Wulff equilibrium morphology formalism have been employed to explore the effect of the reaction conditions, temperature (T), and gas-phase partial pressures (PH2 and PH2S) on the stability of nickel sulfide (Ni3S2) surfaces. Furthermore, the strength and nature of chemical bonds for selected Ni3S2 surface cuts were investigated with the quantum theory of atoms in molecules methodology. A particular analysis of the electrostatic potential within this theoretical framework is performed to study the potential activity of nickel sulfide nanoparticles as hydrodesulfurization (HDS) catalysts. The calculated thermodynamic surface stabilities and the resulting equilibrium morphology model suggest that unsupported Ni3S2 nanoparticles mainly expose (111) and (111) type surface faces in HDS conditions. Analysis of the electrostatic potential mapped onto a selected electron density isocontour (0.001 au) on those expose surface reveals a poor potential reactivity toward electron-donating reagents (i.e., low Lewis acidity). Consequently, a very low attraction between coordinatively unsaturated active sites (Lewis sites) exposed at the catalytic particles and the S atoms coming from reagent polluting molecules does inactive these kinds of particles for HDS.

Shear viscosity in an anisotropic unitary Fermi gas

NASA Astrophysics Data System (ADS)

Samanta, Rickmoy; Sharma, Rishi; Trivedi, Sandip P.

2017-11-01

We consider a system consisting of a strongly interacting, ultracold unitary Fermi gas under harmonic confinement. Our analysis suggests the possibility of experimentally studying, in this system, an anisotropic shear viscosity tensor driven by the anisotropy in the trapping potential. In particular, we suggest that this experimental setup could mimic some features of anisotropic geometries that have recently been studied for strongly coupled field theories which have a dual gravitational description. Results using the AdS/CFT (anti-de Sitter/conformal field theory correspondence) in these theories show that in systems with a background linear potential, certain viscosity components can be made much smaller than the entropy density, parametrically violating the bound proposed by Kovtun, Son, and Starinets (KSS). This intuition, along with results from a Boltzmann analysis that we perform, suggests that a violation of the KSS bound can perhaps occur in the unitary Fermi gas system when it is subjected to a suitable anisotropic trapping potential which may be approximated to be linear in a suitable range of parameters. We give a concrete proposal for an experimental setup where an anisotropic shear viscosity tensor may arise. In such situations, it may also be possible to observe a reduction in the spin-1 component of the shear viscosity from its lowest value observed so far in ultracold Fermi gases. In extreme anisotropic situations, the reduction may be enough to reduce the shear viscosity to entropy ratio below the proposed KSS bound, although this regime is difficult to analyze in a theoretically controlled manner.

Theory of a cylindrical probe in a collisionless magnetoplasma

NASA Technical Reports Server (NTRS)

Laframboise, J. G.; Rubinstein, J.

1976-01-01

A theory is presented for a cylindrical electrostatic probe in a collisionless plasma in the case where the probe axis is inclined at an angle to a uniform magnetic field. The theory is applicable to electron collection, and under more restrictive conditions, to ion collection. For a probe at space potential, the theory is exact in the limit where probe radius is much less than Debye length. At attracting probe potentials, the theory yields an upper bound and an adiabatic limit for current collection. At repelling probe potentials, it provides a lower bound. The theory is valid if the ratios of probe radius to Debye length and probe radius to mean gyroradius are not simultaneously large enough to produce extrema in the probe sheath potential. The numerical current calculations are based on the approximation that particle orbits are helices near the probe, together with the use of kinetic theory to relate velocity distributions near the probe to those far from it. Probe characteristics are presented for inclination angles from 0 to 90 deg and for probe-radius mean-gyroradius ratios from 0.1 to infinity. For an angle of 0 deg, the end-effect current is calculated separately.

Measuring the lensing potential with tomographic galaxy number counts

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

Montanari, Francesco; Durrer, Ruth, E-mail: francesco.montanari@unige.ch, E-mail: ruth.durrer@unige.ch

2015-10-01

We investigate how the lensing potential can be measured tomographically with future galaxy surveys using their number counts. Such a measurement is an independent test of the standard ΛCDM framework and can be used to discern modified theories of gravity. We perform a Fisher matrix forecast based on galaxy angular-redshift power spectra, assuming specifications consistent with future photometric Euclid-like surveys and spectroscopic SKA-like surveys. For the Euclid-like survey we derive a fitting formula for the magnification bias. Our analysis suggests that the cross correlation between different redshift bins is very sensitive to the lensing potential such that the survey canmore » measure the amplitude of the lensing potential at the same level of precision as other standard ΛCDM cosmological parameters.« less

Fused thiophene and its periphery fluorinated substitution derivatives: a theoretical study for organic semiconductors

NASA Astrophysics Data System (ADS)

Wei, Hui-Ling; Shi, Ya-Rui; Liu, Yu-Fang

2015-06-01

A series of phenyl end-capped derivatives of benzo[d,d‧]thieno[3,2-b4,5- b‧]dithiophene (BTDT) with periphery-fluorinated substitutions (PFS) were systematically investigated by using density functional theory (DFT) combined with the Marcus-Hush electron transfer theory. The substituting effects of PFS were discussed. Compared with the original compounds, (i) the PFS compounds have a relatively higher efficiency of charge transport, lower barriers of electron injection, and larger HOMO-LUMO gaps; (ii) the air-stability and the device performance are enhanced by PFS; and (iii) the HOMO-LUMO transitions in the absorption spectrum of the PFS compounds show an obvious blue-shift trend. The perfluorophenylbisbenzo[d, d‧]thieno[3,2-b4,5-b‧]dithiophene (BpF-BTDT) is found to be the most stable and most effective compound in charge transport among the investigated compounds, and it is suggested as an ambipolar semiconducting material. The results of electronic coupling of the bisbenzo[d, d‧]thieno[3,2-b 4,5- b‧]dithiophene (BBTDT) derivatives show that the orbital interaction is mainly contributed by the neighboring molecule in the two dimensional (2D) layer. The PFS compounds have lower oxidization potential, ionization potential, and electron affinity values than the corresponding original ones, which suggest that fluorination can enhance the performance of the thiophene-based organic solar cells. These findings provide a better understanding of the PFS effects on organic semiconductors and may help to design high-performance semiconductor materials.

Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

NASA Astrophysics Data System (ADS)

Wissman, J.; Finkenauer, L.; Deseri, L.; Majidi, C.

2014-10-01

We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K <0). Applying voltage Φ to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ϑ. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theory based on the principle of minimum potential energy to predict the principal curvatures as a function of Φ. Based on this theory, we predict a dependency of ϑ on Φ that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.

Nuclear Fission: from more phenomenology and adjusted parameters to more fundamental theory and increased predictive power

NASA Astrophysics Data System (ADS)

Bulgac, Aurel; Jin, Shi; Magierski, Piotr; Roche, Kenneth; Schunck, Nicolas; Stetcu, Ionel

2017-11-01

Two major recent developments in theory and computational resources created the favorable conditions for achieving a microscopic description of fission dynamics in classically allowed regions of the collective potential energy surface, almost eighty years after its discovery in 1939 by Hahn and Strassmann [1]. The first major development was in theory, the extension of the Time-Dependent Density Functional Theory (TDDFT) [2-5] to superfluid fermion systems [6]. The second development was in computing, the emergence of powerful enough supercomputers capable of solving the complex systems of equations describing the time evolution in three dimensions without any restrictions of hundreds of strongly interacting nucleons. Thus the conditions have been created to renounce phenomenological models and incomplete microscopic treatments with uncontrollable approximations and/or assumptions in the description of the complex dynamics of fission. Even though the available nuclear energy density functionals (NEDFs) are phenomenological still, their accuracy is improving steadily and the prospects of being able to perform calculations of the nuclear fission dynamics and to predict many properties of the fission fragments, otherwise not possible to extract from experiments.

"Found Performance": Towards a Musical Methodology for Exploring the Aesthetics of Care.

PubMed

Wood, Stuart

2017-09-18

Concepts of performance in fine art reflect key processes in music therapy. Music therapy enables practitioners to reframe patients as performers, producing new meanings around the clinical knowledge attached to medical histories and constructs. In this paper, music therapy practices are considered in the wider context of art history, with reference to allied theories from social research. Tracing a century in art that has revised the performativity of found objects (starting with Duchamp's "Fountain"), and of found sound (crystallised by Cage's 4' 33) this paper proposes that music therapy might be a pioneer methodology of "found performance". Examples from music therapy and contemporary socially engaged art practices are brought as potential links between artistic methodologies and medical humanities research, with specific reference to notions of Aesthetics of Care.

Attribution of movement: Potential links between subjective reports of agency and output monitoring.

PubMed

Sugimori, Eriko; Asai, Tomohisa

2015-01-01

According to agency memory theory, individuals decide whether "I did it" based on a memory trace of "I am doing it". The purpose of this study was to validate the agency memory theory. To this end, several hand actions were individually presented as samples, and participants were asked to perform the sample action, observe the performance of that action by another person, or imagine performing the action. Online feedback received by the participants during the action was manipulated among the different conditions, and output monitoring, in which participants were asked whether they had performed each hand action, was conducted. The rate at which respondents thought that they themselves had performed the action was higher when visual feedback was unaltered than when it was altered (Experiment 1A), and this tendency was observed across all types of altered feedback (Experiment 1B). The observation of an action performed by the hand of another person did not increase the rate at which respondents thought that they themselves had performed the action unless the participants actually did perform the action (Experiments 2A and 2B). In Experiment 3, a relationship was observed between the subjective feeling that "I am the one who is causing an action" and the memory that "I did perform the action". These experiments support the hypothesis that qualitative information and sense of "self" are tagged in a memory trace and that such tags can be used as cues for judgements when the memory is related to the "self".

Hemispheric asymmetry and theory of mind: is there an association?

PubMed

Herzig, Daniela A; Sullivan, Sarah; Evans, Jonathan; Corcoran, Rhiannon; Mohr, Christine

2012-01-01

In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations. Healthy participants (n=129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only). The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of "overinterpreting" the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

Doping Attitudes and Covariates of Potential Doping Behaviour in High-Level Team-Sport Athletes; Gender Specific Analysis

PubMed Central

Sekulic, Damir; Tahiraj, Enver; Zvan, Milan; Zenic, Natasa; Uljevic, Ognjen; Lesnik, Blaz

2016-01-01

Team sports are rarely studied with regard to doping behaviour and doping-related factors regardless of their global popularity. This study aimed to investigate doping factors and covariates of potential doping behaviour in high-level team-sport athletes. The subjects were 457 high-performing, national- and international-level athletes (21.9 ± 3.4 years of age; 179 females) involved in volleyball (n = 77), soccer (n = 163), basketball (n = 114) and handball (n = 103). Previously validated self-administered questionnaires aimed at evidencing sport factors, doping-related factors, knowledge on sport nutrition and doping, and attitudes to performance enhancement were used. The results indicated a higher doping likelihood in male athletes, with a significant gender difference for basketball and handball. In males, a higher doping likelihood is found for athletes who had achieved better results at junior-age level, those who regularly consume dietary supplements, and who perceive their sport as being contaminated by doping. A higher sport achievement at senior-age level is protective against potential doping behaviour in males. In females, a higher likelihood of doping is evidenced in those athletes involved in binge drinking, while a lower tendency for doping is evidenced in female athletes who possess better knowledge on sport nutrition. Knowledge about doping is very low and thus education about doping is urgently needed. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in females. Future studies should consider other approaches and theories, such as theory of planned behaviour and/or social-cognitive theory, in studying the problem of doping behaviour in team-sports. Key points The doping knowledge among Kosovar team-sport athletes is very low and systematic anti-doping education is urgently needed. The highest risk of doping behaviour in males is found for those athletes who had been successful in their junior age and those who consume dietary supplements. An improvement of knowledge on sport nutrition might be a potentially effective method for reducing the tendency for doping in female team-sport athletes. While the associations between the studied factors and doping behaviour are different between males and females, the gender-specific approach to exploring the covariates of doping behaviour is warranted. PMID:27928206

Theory and design of interferometric synthetic aperture radars

NASA Technical Reports Server (NTRS)

Rodriguez, E.; Martin, J. M.

1992-01-01

A derivation of the signal statistics, an optimal estimator of the interferometric phase, and the expression necessary to calculate the height-error budget are presented. These expressions are used to derive methods of optimizing the parameters of the interferometric synthetic aperture radar system (InSAR), and are then employed in a specific design example for a system to perform high-resolution global topographic mapping with a one-year mission lifetime, subject to current technological constraints. A Monte Carlo simulation of this InSAR system is performed to evaluate its performance for realistic topography. The results indicate that this system has the potential to satisfy the stringent accuracy and resolution requirements for geophysical use of global topographic data.

Study of the Hyperon-Nucleon Interaction in Exclusive Λ Photoproduction off the Deuteron

NASA Astrophysics Data System (ADS)

Zachariou, Nicholas; CLAS Collaboration

2014-09-01

Understanding the nature of the nuclear force in terms of the fundamental degrees of freedom of the theory of strong interaction, Quantum Chromodynamics (QCD), is one of the primary goals of modern nuclear physics. While the nucleon-nucleon (NN) interaction has been studied for decades, a systematic description of the NN potential has been achieved only recently with the development of low-energy Effective Field Theories (EFT). To obtain a comprehensive understanding of the strong interaction, dynamics involving strange baryons must be studied. Currently, little is known about the properties of the hyperon-nucleon (YN) and the hyperon-hyperon (YY) interactions. In this talk I will describe our current research of the Λn interaction using the E06-103 experiment performed with the CLAS detector in Hall B at Jefferson Lab. The large kinematic coverage of the CLAS combined with the exceptionally high quality of the experimental data allows to identify and select final-state interaction events in the reaction γd -->K+ Λn and to establish their kinematical dependencies. The large set of observables we aim to obtain will provide tight constraints on modern YN potentials. I will present the current status of the project and will discuss future incentives. Understanding the nature of the nuclear force in terms of the fundamental degrees of freedom of the theory of strong interaction, Quantum Chromodynamics (QCD), is one of the primary goals of modern nuclear physics. While the nucleon-nucleon (NN) interaction has been studied for decades, a systematic description of the NN potential has been achieved only recently with the development of low-energy Effective Field Theories (EFT). To obtain a comprehensive understanding of the strong interaction, dynamics involving strange baryons must be studied. Currently, little is known about the properties of the hyperon-nucleon (YN) and the hyperon-hyperon (YY) interactions. In this talk I will describe our current research of the Λn interaction using the E06-103 experiment performed with the CLAS detector in Hall B at Jefferson Lab. The large kinematic coverage of the CLAS combined with the exceptionally high quality of the experimental data allows to identify and select final-state interaction events in the reaction γd -->K+ Λn and to establish their kinematical dependencies. The large set of observables we aim to obtain will provide tight constraints on modern YN potentials. I will present the current status of the project and will discuss future incentives. for the CLAS Collaboration.

Assessing photocatalytic power of g-C{sub 3}N{sub 4} for solar fuel production: A first-principles study involving quasi-particle theory and dispersive forces

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

Osorio-Guillén, J. M., E-mail: mario.osorio@udea.edu.co; Espinosa-García, W. F.; Grupo de Investigación en Modelamiento y Simulación Computacional, Facultad de Ingenierías, Universidad de San Buenaventura Seccional Medellín, Carrera 56C No 51-110, Medellín

2015-09-07

First-principles quasi-particle theory has been employed to assess catalytic power of graphitic carbon nitride, g-C{sub 3}N{sub 4}, for solar fuel production. A comparative study between g-h-triazine and g-h-heptazine has been carried out taking also into account van der Waals dispersive forces. The band edge potentials have been calculated using a recently developed approach where quasi-particle effects are taken into account through the GW approximation. First, it was found that the description of ground state properties such as cohesive and surface formation energies requires the proper treatment of dispersive interaction. Furthermore, through the analysis of calculated band-edge potentials, it is shownmore » that g-h-triazine has high reductive power reaching the potential to reduce CO{sub 2} to formic acid, coplanar g-h-heptazine displays the highest thermodynamics force toward H{sub 2}O/O{sub 2} oxidation reaction, and corrugated g-h-heptazine exhibits a good capacity for both reactions. This rigorous theoretical study shows a route to further improve the catalytic performance of g-C{sub 3}N{sub 4}.« less

Triphenylamine based organic dyes for dye sensitized solar cells: A theoretical approach

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

Mohankumar, V.; Pandian, Muthu Senthil; Ramasamy, P., E-mail: ramasamyp@ssn.edu.in

2016-05-23

The geometry, electronic structure and absorption spectra for newly designed triphenylamine based organic dyes were investigated by density functional theory (DFT) and time dependent density functional theory (TD-DFT) with the Becke 3-Parameter-Lee-Yang-parr(B3LYP) functional, where the 6-31G(d,p) basis set was employed. All calculations were performed using the Gaussian 09 software package. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. Ultraviolet–visible (UV–vis) spectrum was simulated by TD-DFT in gas phase. The calculation shows that all of the dyes can potentially be good sensitizers for DSSC. The LUMOs are just above the conduction band of TiO{sub 2}more » and their HOMOs are under the reduction potential energy of the electrolytes (I{sup −}/I{sub 3}{sup −}) which can facilitate electron transfer from the excited dye to TiO{sub 2} and charge regeneration process after photo oxidation respectively. The simulated absorption spectrum of dyes match with solar spectrum. Frontier molecular orbital results show that among all the three dyes, the “dye 3” can be used as potential sensitizer for DSSC.« less

Assessing photocatalytic power of g-C3N4 for solar fuel production: A first-principles study involving quasi-particle theory and dispersive forces.

PubMed

Osorio-Guillén, J M; Espinosa-García, W F; Moyses Araujo, C

2015-09-07

First-principles quasi-particle theory has been employed to assess catalytic power of graphitic carbon nitride, g-C3N4, for solar fuel production. A comparative study between g-h-triazine and g-h-heptazine has been carried out taking also into account van der Waals dispersive forces. The band edge potentials have been calculated using a recently developed approach where quasi-particle effects are taken into account through the GW approximation. First, it was found that the description of ground state properties such as cohesive and surface formation energies requires the proper treatment of dispersive interaction. Furthermore, through the analysis of calculated band-edge potentials, it is shown that g-h-triazine has high reductive power reaching the potential to reduce CO2 to formic acid, coplanar g-h-heptazine displays the highest thermodynamics force toward H2O/O2 oxidation reaction, and corrugated g-h-heptazine exhibits a good capacity for both reactions. This rigorous theoretical study shows a route to further improve the catalytic performance of g-C3N4.

Applying and advancing behavior change theories and techniques in the context of a digital health revolution: Proposals for more effectively realizing untapped potential

PubMed Central

Moller, Arlen C.; Merchant, Gina; Conroy, David E.; West, Robert; Hekler, Eric B.; Kugler, Kari C.; Michie, Susan

2017-01-01

As more behavioral health interventions move from traditional to digital platforms, the application of evidence-based theories and techniques may be doubly advantageous. First, it can expedite digital health intervention development, improving efficacy, and increasing reach. Second, moving behavioral health interventions to digital platforms presents researchers with novel (potentially paradigm shifting) opportunities for advancing theories and techniques. In particular, the potential for technology to revolutionize theory refinement is made possible by leveraging the proliferation of “real-time” objective measurement and “big data” commonly generated and stored by digital platforms. Much more could be done to realize this potential. This paper offers proposals for better leveraging the potential advantages of digital health platforms, and reviews three of the cutting edge methods for doing so: optimization designs, dynamic systems modeling, and social network analysis. PMID:28058516

Optimization Design of Minimum Total Resistance Hull Form Based on CFD Method

NASA Astrophysics Data System (ADS)

Zhang, Bao-ji; Zhang, Sheng-long; Zhang, Hui

2018-06-01

In order to reduce the resistance and improve the hydrodynamic performance of a ship, two hull form design methods are proposed based on the potential flow theory and viscous flow theory. The flow fields are meshed using body-fitted mesh and structured grids. The parameters of the hull modification function are the design variables. A three-dimensional modeling method is used to alter the geometry. The Non-Linear Programming (NLP) method is utilized to optimize a David Taylor Model Basin (DTMB) model 5415 ship under the constraints, including the displacement constraint. The optimization results show an effective reduction of the resistance. The two hull form design methods developed in this study can provide technical support and theoretical basis for designing green ships.

Aspects Topologiques de la Theorie des Champs et leurs Applications

NASA Astrophysics Data System (ADS)

Caenepeel, Didier

This thesis is dedicated to the study of various topological aspects of field theory, and is divided in three parts. In two space dimensions the possibility of fractional statistics can be implemented by adding an appropriate "fictitious" electric charge and magnetic flux to each particle (after which they are known as anyons). Since the statistical interaction is rather difficult to handle, a mean-field approximation is used in order to describe a gas of anyons. We derive a criterion for the validity of this approximation using the inherent feature of parity violation in the scattering of anyons. We use this new method in various examples of anyons and show both analytically and numerically that the approximation is justified if the statistical interaction is weak, and that it must be more weak for boson-based than for fermion-based anyons. Chern-Simons theories give an elegant implementation of anyonic properties in field theories, which permits the emergence of new mechanisms for anyon superconductivity. Since it is reasonable to think that superconductivity is a low energy phenomenon, we have been interested in non-relativistic C-S systems. We present the scalar field effective potential for non-relativistic matter coupled to both Abelian and non-Abelian C-S gauge fields. We perform the calculations using functional methods in background fields. Finally, we compute the scalar effective potential in various gauges and treat divergences with various regularization schemes. In three space dimensions, a generalization of Chern-Simons theory may be achieved by introducing an antisymmetric tensor gauge field. We use these theories, called B wedge F theories, to present an alternative to the Higgs mechanism to generate masses for non-Abelian gauge fields. The initial Lagrangian is composed of a fermion with current-current and dipole-dipole type self -interactions minimally coupled to non-Abelian gauge fields. The mass generation occurs upon the fermionic functional integration. We show that by suitably adjusting the coupling constants the effective theory contains massive non-Abelian gauge fields without any residual scalars or other degrees of freedom.

The Examination of Reliability According to Classical Test and Generalizability on a Job Performance Scale

ERIC Educational Resources Information Center

Yelboga, Atilla; Tavsancil, Ezel

2010-01-01

In this research, the classical test theory and generalizability theory analyses were carried out with the data obtained by a job performance scale for the years 2005 and 2006. The reliability coefficients obtained (estimated) from the classical test theory and generalizability theory analyses were compared. In classical test theory, test retest…

A global reaction route mapping-based kinetic Monte Carlo algorithm

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

Mitchell, Izaac; Page, Alister J., E-mail: sirle@chem.nagoya-u.ac.jp, E-mail: alister.page@newcastle.edu.au; Irle, Stephan, E-mail: sirle@chem.nagoya-u.ac.jp, E-mail: alister.page@newcastle.edu.au

2016-07-14

We propose a new on-the-fly kinetic Monte Carlo (KMC) method that is based on exhaustive potential energy surface searching carried out with the global reaction route mapping (GRRM) algorithm. Starting from any given equilibrium state, this GRRM-KMC algorithm performs a one-step GRRM search to identify all surrounding transition states. Intrinsic reaction coordinate pathways are then calculated to identify potential subsequent equilibrium states. Harmonic transition state theory is used to calculate rate constants for all potential pathways, before a standard KMC accept/reject selection is performed. The selected pathway is then used to propagate the system forward in time, which is calculatedmore » on the basis of 1st order kinetics. The GRRM-KMC algorithm is validated here in two challenging contexts: intramolecular proton transfer in malonaldehyde and surface carbon diffusion on an iron nanoparticle. We demonstrate that in both cases the GRRM-KMC method is capable of reproducing the 1st order kinetics observed during independent quantum chemical molecular dynamics simulations using the density-functional tight-binding potential.« less

Reading with peripheral vision: a comparison of reading dynamic scrolling and static text with a simulated central scotoma.

PubMed

Harvey, Hannah; Walker, Robin

2014-05-01

Horizontally scrolling text is, in theory, ideally suited to enhance viewing strategies recommended to improve reading performance under conditions of central vision loss such as macular disease, although it is largely unproven in this regard. This study investigated if the use of scrolling text produced an observable improvement in reading performed under conditions of eccentric viewing in an artificial scotoma paradigm. Participants (n=17) read scrolling and static text with a central artificial scotoma controlled by an eye-tracker. There was an improvement in measures of reading accuracy, and adherence to eccentric viewing strategies with scrolling, compared to static, text. These findings illustrate the potential benefits of scrolling text as a potential reading aid for those with central vision loss. Copyright © 2014 Elsevier B.V. All rights reserved.

Structural, electronic, optical and thermoelectric investigations of antiperovskites A3SnO (A = Ca, Sr, Ba) using density functional theory

NASA Astrophysics Data System (ADS)

Hassan, M.; Shahid, A.; Mahmood, Q.

2018-02-01

Density functional theory study of the structural, electrical, optical and thermoelectric behaviors of very less investigated anti-perovskites A3SnO (A = Ca, Sr, Ba) is performed with FP-LAPW technique. The A3SnO exhibit narrow direct band gap, in contrast to the wide indirect band gap of the respective perovskites. Hence, indirect to direct band gap transformation can be realized by the structural transition from perovskite to anti-perovskite. The p-p hybridization between A and O states result in the covalent bonding. The transparency and maximum reflectivity to the certain energies, and the verification of the Penn's model indicate potential optical device applications. Thermoelectric behaviors computed within 200-800 K depict that Ca3SnO exhibits good thermoelectric performance than Ba3SnO and Sr3SnO, and all three operate at their best at 800 K suggesting high temperature thermoelectric device applications.

Effect of vacancy defects on generalized stacking fault energy of fcc metals.

PubMed

Asadi, Ebrahim; Zaeem, Mohsen Asle; Moitra, Amitava; Tschopp, Mark A

2014-03-19

Molecular dynamics (MD) and density functional theory (DFT) studies were performed to investigate the influence of vacancy defects on generalized stacking fault (GSF) energy of fcc metals. MEAM and EAM potentials were used for MD simulations, and DFT calculations were performed to test the accuracy of different common parameter sets for MEAM and EAM potentials in predicting GSF with different fractions of vacancy defects. Vacancy defects were placed at the stacking fault plane or at nearby atomic layers. The effect of vacancy defects at the stacking fault plane and the plane directly underneath of it was dominant compared to the effect of vacancies at other adjacent planes. The effects of vacancy fraction, the distance between vacancies, and lateral relaxation of atoms on the GSF curves with vacancy defects were investigated. A very similar variation of normalized SFEs with respect to vacancy fractions were observed for Ni and Cu. MEAM potentials qualitatively captured the effect of vacancies on GSF.

Physical Meaning of Virtual Kohn-Sham Orbitals and Orbital Energies: An Ideal Basis for the Description of Molecular Excitations.

PubMed

van Meer, R; Gritsenko, O V; Baerends, E J

2014-10-14

In recent years, several benchmark studies on the performance of large sets of functionals in time-dependent density functional theory (TDDFT) calculations of excitation energies have been performed. The tested functionals do not approximate exact Kohn-Sham orbitals and orbital energies closely. We highlight the advantages of (close to) exact Kohn-Sham orbitals and orbital energies for a simple description, very often as just a single orbital-to-orbital transition, of molecular excitations. Benchmark calculations are performed for the statistical average of orbital potentials (SAOP) functional for the potential [J. Chem. Phys. 2000, 112, 1344; 2001, 114, 652], which approximates the true Kohn-Sham potential much better than LDA, GGA, mGGA, and hybrid potentials do. An accurate Kohn-Sham potential does not only perform satisfactorily for calculated vertical excitation energies of both valence and Rydberg transitions but also exhibits appealing properties of the KS orbitals including occupied orbital energies close to ionization energies, virtual-occupied orbital energy gaps very close to excitation energies, realistic shapes of virtual orbitals, leading to straightforward interpretation of most excitations as single orbital transitions. We stress that such advantages are completely lost in time-dependent Hartree-Fock and partly in hybrid approaches. Many excitations and excitation energies calculated with local density, generalized gradient, and hybrid functionals are spurious. There is, with an accurate KS, or even the LDA or GGA potentials, nothing problematic about the "band gap" in molecules: the HOMO-LUMO gap is close to the first excitation energy (the optical gap).

Robust global identifiability theory using potentials--Application to compartmental models.

PubMed

Wongvanich, N; Hann, C E; Sirisena, H R

2015-04-01

This paper presents a global practical identifiability theory for analyzing and identifying linear and nonlinear compartmental models. The compartmental system is prolonged onto the potential jet space to formulate a set of input-output equations that are integrals in terms of the measured data, which allows for robust identification of parameters without requiring any simulation of the model differential equations. Two classes of linear and non-linear compartmental models are considered. The theory is first applied to analyze the linear nitrous oxide (N2O) uptake model. The fitting accuracy of the identified models from differential jet space and potential jet space identifiability theories is compared with a realistic noise level of 3% which is derived from sensor noise data in the literature. The potential jet space approach gave a match that was well within the coefficient of variation. The differential jet space formulation was unstable and not suitable for parameter identification. The proposed theory is then applied to a nonlinear immunological model for mastitis in cows. In addition, the model formulation is extended to include an iterative method which allows initial conditions to be accurately identified. With up to 10% noise, the potential jet space theory predicts the normalized population concentration infected with pathogens, to within 9% of the true curve. Copyright © 2015 Elsevier Inc. All rights reserved.

Inflation in anisotropic scalar-tensor theories

NASA Technical Reports Server (NTRS)

Pimentel, Luis O.; Stein-Schabes, Jaime

1988-01-01

The existence of an inflationary phase in anisotropic Scalar-Tensor Theories is investigated by means of a conformal transformation that allows us to rewrite these theories as gravity minimally coupled to a scalar field with a nontrivial potential. The explicit form of the potential is then used and the No Hair Theorem concludes that there is an inflationary phase in all open or flat anisotropic spacetimes in these theories. Several examples are constructed where the effect becomes manifest.

A Van der Waals-like theory of plasma double layers

NASA Technical Reports Server (NTRS)

Katz, Ira; Davis, V. A.

1989-01-01

A theory describing plasma double layers in terms of multiple roots of the charge density expression is presented. The theory presented uses the fact that equilibrium plasmas shield small potential perturbations linearly; for high potentials, the shielding decreases. The approach is analogous to Van der Waals' theory of simple fluids in which inclusion of approximate expressions for both excluded volume and long range attractive forces sufficiently describes the first-order liquid-gas phase transition.

Catching the PEG-induced attractive interaction between proteins.

PubMed

Vivarès, D; Belloni, L; Tardieu, A; Bonneté, F

2002-09-01

We present the experimental and theoretical background of a method to characterize the protein-protein attractive potential induced by one of the mostly used crystallizing agents in the protein-field, the poly(ethylene glycol) (PEG). This attractive interaction is commonly called, in colloid physics, the depletion interaction. Small-Angle X-ray Scattering experiments and numerical treatments based on liquid-state theories were performed on urate oxidase-PEG mixtures with two different PEGs (3350 Da and 8000 Da). A "two-component" approach was used in which the polymer-polymer, the protein-polymer and the protein-protein pair potentials were determined. The resulting effective protein-protein potential was characterized. This potential is the sum of the free-polymer protein-protein potential and of the PEG-induced depletion potential. The depletion potential was found to be hardly dependent upon the protein concentration but strongly function of the polymer size and concentration. Our results were also compared with two models, which give an analytic expression for the depletion potential.

How to make thermodynamic perturbation theory to be suitable for low temperature?

NASA Astrophysics Data System (ADS)

Zhou, Shiqi

2009-02-01

Low temperature unsuitability is a problem plaguing thermodynamic perturbation theory (TPT) for years. Present investigation indicates that the low temperature predicament can be overcome by employing as reference system a nonhard sphere potential which incorporates one part of the attractive ingredient in a potential function of interest. In combination with a recently proposed TPT [S. Zhou, J. Chem. Phys. 125, 144518 (2006)] based on a λ expansion (λ being coupling parameter), the new perturbation strategy is employed to predict for several model potentials. It is shown that the new perturbation strategy can very accurately predict various thermodynamic properties even if the potential range is extremely short and hence the temperature of interest is very low and current theoretical formalisms seriously deteriorate or critically fail to predict even the existence of the critical point. Extensive comparison with existing liquid state theories and available computer simulation data discloses a superiority of the present TPT to two Ornstein-Zernike-type integral equation theories, i.e., hierarchical reference theory and self-consistent Ornstein-Zernike approximation.

How to make thermodynamic perturbation theory to be suitable for low temperature?

PubMed

Zhou, Shiqi

2009-02-07

Low temperature unsuitability is a problem plaguing thermodynamic perturbation theory (TPT) for years. Present investigation indicates that the low temperature predicament can be overcome by employing as reference system a nonhard sphere potential which incorporates one part of the attractive ingredient in a potential function of interest. In combination with a recently proposed TPT [S. Zhou, J. Chem. Phys. 125, 144518 (2006)] based on a lambda expansion (lambda being coupling parameter), the new perturbation strategy is employed to predict for several model potentials. It is shown that the new perturbation strategy can very accurately predict various thermodynamic properties even if the potential range is extremely short and hence the temperature of interest is very low and current theoretical formalisms seriously deteriorate or critically fail to predict even the existence of the critical point. Extensive comparison with existing liquid state theories and available computer simulation data discloses a superiority of the present TPT to two Ornstein-Zernike-type integral equation theories, i.e., hierarchical reference theory and self-consistent Ornstein-Zernike approximation.

Alkaline earth lead and tin compounds Ae2Pb, Ae2Sn, Ae = Ca, Sr, Ba, as thermoelectric materials

PubMed Central

Parker, David; Singh, David J

2013-01-01

We present a detailed theoretical study of three alkaline earth compounds Ca2Pb, Sr2Pb and Ba2Pb, which have undergone little previous study, calculating electronic band structures and Boltzmann transport and bulk moduli using density functional theory. We also study the corresponding tin compounds Ca2Sn, Sr2Sn and Ba2Sn. We find that these are all narrow band gap semiconductors with an electronic structure favorable for thermoelectric performance, with substantial thermopowers for the lead compounds at temperature ranges from 300 to 800 K. For the lead compounds, we further find very low calculated bulk moduli—roughly half of the values for the lead chalcogenides, suggestive of soft phonons and hence low lattice thermal conductivity. All these facts indicate that these materials merit experimental investigation as potential high performance thermoelectrics. We find good potential for thermoelectric performance in the environmentally friendly stannide materials, particularly at high temperature. PMID:27877610

Theoretical characterisation of highly efficient dye-sensitised solar cells

NASA Astrophysics Data System (ADS)

Shalabi, A. S.; El Mahdy, A. M.; Assem, M. M.; Taha, H. O.; Abdel Halim, W. S.

2014-01-01

Molecular electronic structure calculations, employing density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methodologies, have been carried out to improve the performance of the synthesised dye YD2-o-C8 which is characterised by 11.9%-12.7% efficiencies. We aimed to narrow the band gap of YD2-o-C8 to extend the light-harvesting region to near-infrared (NIR). This was done by incorporating Cd instead of Zn onto the porphyrin ring and elongating the length of π-conjugation by adding ethynylene link and anthracene unit, so that the performances of the suggested cells could be expected to exceed the 11.9%-12.7% efficiencies with TiO2, ZnO2, and WO3 oxide electrodes. The effects of modifying the central metal and elongating the length of π-conjugation on cell performance are confirmed in terms of frontier molecular orbital (FMO) energy gaps, density of states (DOS), molecular electrostatic potentials (MEPs), non-linear optical (NLO) properties, ultraviolet-visible (UV-vis) electronic absorption, and 1H nuclear magnetic resonance chemical shifts. Increasing the length of π-conjugation of the D-π-A dyes leads to increasing the DOS near Fermi levels, more active NLO performance, strong response to the external electric field, delocalisation of the negative charges near the anchoring groups, deep electron injection, suppressing macrocycle aggregation, active dye regeneration, and inhibited dye recombination. The calculated band gap/eV of the present DMP-Zn is correlated with the experimental (E1/2(oxidation)-E1/2(reduction)/V) potentials of the identical YD2-o-C8. A co-sensitiser is suggested for NIR sensitisation (550-950 nm) to increase the power-to-conversion efficiency beyond 14%.

A neural-network potential through charge equilibration for WS2: From clusters to sheets

NASA Astrophysics Data System (ADS)

Hafizi, Roohollah; Ghasemi, S. Alireza; Hashemifar, S. Javad; Akbarzadeh, Hadi

2017-12-01

In the present work, we use a machine learning method to construct a high-dimensional potential for tungsten disulfide using a charge equilibration neural-network technique. A training set of stoichiometric WS2 clusters is prepared in the framework of density functional theory. After training the neural-network potential, the reliability and transferability of the potential are verified by performing a crystal structure search on bulk phases of WS2 and by plotting energy-area curves of two different monolayers. Then, we use the potential to investigate various triangular nano-clusters and nanotubes of WS2. In the case of nano-structures, we argue that 2H atomic configurations with sulfur rich edges are thermodynamically more stable than the other investigated configurations. We also studied a number of WS2 nanotubes which revealed that 1T tubes with armchair chirality exhibit lower bending stiffness.

Gaussian approximation potential modeling of lithium intercalation in carbon nanostructures

NASA Astrophysics Data System (ADS)

Fujikake, So; Deringer, Volker L.; Lee, Tae Hoon; Krynski, Marcin; Elliott, Stephen R.; Csányi, Gábor

2018-06-01

We demonstrate how machine-learning based interatomic potentials can be used to model guest atoms in host structures. Specifically, we generate Gaussian approximation potential (GAP) models for the interaction of lithium atoms with graphene, graphite, and disordered carbon nanostructures, based on reference density functional theory data. Rather than treating the full Li-C system, we demonstrate how the energy and force differences arising from Li intercalation can be modeled and then added to a (prexisting and unmodified) GAP model of pure elemental carbon. Furthermore, we show the benefit of using an explicit pair potential fit to capture "effective" Li-Li interactions and to improve the performance of the GAP model. This provides proof-of-concept for modeling guest atoms in host frameworks with machine-learning based potentials and in the longer run is promising for carrying out detailed atomistic studies of battery materials.

Correlation energy, correlated electron density, and exchange-correlation potential in some spherically confined atoms.

PubMed

Vyboishchikov, Sergei F

2016-12-05

We report correlation energies, electron densities, and exchange-correlation potentials obtained from configuration interaction and density functional calculations on spherically confined He, Be, Be 2+ , and Ne atoms. The variation of the correlation energy with the confinement radius R c is relatively small for the He, Be 2+ , and Ne systems. Curiously, the Lee-Yang-Parr (LYP) functional works well for weak confinements but fails completely for small R c . However, in the neutral beryllium atom the CI correlation energy increases markedly with decreasing R c . This effect is less pronounced at the density-functional theory level. The LYP functional performs very well for the unconfined Be atom, but fails badly for small R c . The standard exchange-correlation potentials exhibit significant deviation from the "exact" potential obtained by inversion of Kohn-Sham equation. The LYP correlation potential behaves erratically at strong confinements. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Pattern detection in forensic case data using graph theory: application to heroin cutting agents.

PubMed

Terrettaz-Zufferey, Anne-Laure; Ratle, Frédéric; Ribaux, Olivier; Esseiva, Pierre; Kanevski, Mikhail

2007-04-11

Pattern recognition techniques can be very useful in forensic sciences to point out to relevant sets of events and potentially encourage an intelligence-led style of policing. In this study, these techniques have been applied to categorical data corresponding to cutting agents found in heroin seizures. An application of graph theoretic methods has been performed, in order to highlight the possible relationships between the location of seizures and co-occurrences of particular heroin cutting agents. An analysis of the co-occurrences to establish several main combinations has been done. Results illustrate the practical potential of mathematical models in forensic data analysis.

Conflict and Gaming in Instruction and Performance.

ERIC Educational Resources Information Center

Kowitz, Gerald T.; Smith, Jay C.

1989-01-01

Discussion of instruction and training to introduce new ideas and to improve performance focuses on the presence of conflict and the theory of games. Topics discussed include learner participation; Theory X; Theory Y; and Theory Z; and game rules, including control, scoring, changing rules, and ending the game. (25 references) (LRW)

Social cognition in anorexia nervosa: evidence of preserved theory of mind and impaired emotional functioning.

PubMed

Adenzato, Mauro; Todisco, Patrizia; Ardito, Rita B

2012-01-01

The findings of the few studies that have to date investigated the way in which individuals with Anorexia Nervosa (AN) navigate their social environment are somewhat contradictory. We undertook this study to shed new light on the social-cognitive profile of patients with AN, analysing Theory of Mind and emotional functioning. Starting from previous evidence on the role of the amygdala in the neurobiology of AN and in the social cognition, we hypothesise preserved Theory of Mind and impaired emotional functioning in patients with AN. Thirty women diagnosed with AN and thirty-two women matched for education and age were involved in the study. Theory of Mind and emotional functioning were assessed with a set of validated experimental tasks. A measure of perceived social support was also used to test the correlations between this dimension and the social-cognitive profile of AN patients. The performance of patients with AN is significantly worse than that of healthy controls on tasks assessing emotional functioning, whereas patients' performance is comparable to that of healthy controls on the Theory of Mind task. Correlation analyses showed no relationship between scores on any of the social-cognition tasks and either age of onset or duration of illness. A correlation between social support and emotional functioning was found. This latter result seems to suggest a potential role of social support in the treatment and recovery of AN. The pattern of results followed the experimental hypothesis. They may be useful to help us better understand the social-cognitive profile of patients with AN and to contribute to the development of effective interventions based on the ways in which patients with AN actually perceive their social environment.

Statistical substantiation of the van der Waals theory of inhomogeneous fluids

NASA Astrophysics Data System (ADS)

Baidakov, V. G.; Protsenko, S. P.; Chernykh, G. G.; Boltachev, G. Sh.

2002-04-01

Computer experiments on simulation of thermodynamic properties and structural characteristics of a Lennard-Jones fluid in one- and two-phase models have been performed for the purpose of checking the base concepts of the van der Waals theory. Calculations have been performed by the method of molecular dynamics at cutoff radii of the intermolecular potential rc,1=2.6σ and rc,2=6.78σ. The phase equilibrium parameters, surface tension, and density distribution have been determined in a two-phase model with a flat liquid-vapor interface. The strong dependence of these properties on the value of rc is shown. The p,ρ,T properties and correlation functions have been calculated in a homogeneous model for a stable and a metastable fluid. An equation of state for a Lennard-Jones fluid describing stable, metastable, and labile regions has been built. It is shown that at T>=1.1 the properties of a flat interface within the computer experimental error can be described by the van der Waals square-gradient theory with an influence parameter κ independent of the density. Taking into account the density dependence of κ through the second moment of the direct correlation function will deteriorate the agreement of the theory with data of computer simulation. The contribution of terms of a higher order than (∇ρ)2 to the Helmholtz free energy of an inhomogeneous system has been considered. It is shown that taking into account terms proportional to (∇ρ)4 leaves no way of obtaining agreement between the theory and simulation data, while taking into consideration of terms proportional to (∇ρ)6 makes it possible to describe with adequate accuracy all the properties of a flat interface in the temperature range from the triple to the critical point.

Combine experimental and theoretical investigation on an alkaloid-Dimethylisoborreverine

NASA Astrophysics Data System (ADS)

Singh, Swapnil; Singh, Harshita; Karthick, T.; Agarwal, Parag; Erande, Rohan D.; Dethe, Dattatraya H.; Tandon, Poonam

2016-01-01

A combined experimental (FT-IR, 1H and 13C NMR) and theoretical approach is used to study the structure and properties of antimalarial drug dimethylisoborreverine (DMIB). Conformational analysis, has been performed by plotting one dimensional potential energy curve that was computed using density functional theory (DFT) with B3LYP/6-31G method and predicted conformer A1 as the most stable conformer. After full geometry optimization, harmonic wavenumbers were computed for conformer A1 at the DFT/B3LYP/6-311++G(d,P) level. A complete vibrational assignment of all the vibrational modes have been performed on the bases of the potential energy distribution (PED) and theoretical results were found to be in good agreement with the observed data. To predict the solvent effect, the UV-Vis spectra were calculated in different solvents by polarizable continuum model using TD-DFT method. Molecular docking studies were performed to test the biological activity of the sample using SWISSDOCK web server and Hex 8.0.0 software. The molecular electrostatic potential (MESP) was plotted to identify the reactive sites of the molecule. Natural bond orbital (NBO) analysis was performed to get a deep insight of intramolecular charge transfer. Thermodynamical parameters were calculated to predict the direction of chemical reaction.

A combined experimental and DFT study of a novel unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine

NASA Astrophysics Data System (ADS)

Vijaya, P.; Sankaran, K. R.

2015-03-01

A novel unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine (UA) was prepared and characterized by IR, 1H and 13C NMR spectral studies. A 2D - potential energy scan (PES) of p-isobutylacetophenone (IBAP) was the portal to the conformational analysis of UA by density functional theory (DFT) methods using 6-31G(d,p) basis set by Gaussian 03 program. The theoretical IR frequencies were found to be in good agreement with the experimental values. The IR frequencies of UA were analyzed by means of Potential energy Distribution (PED %) calculation using Vibrational Energy Distribution Analysis (VEDA 4) program. The experimental NMR chemical shift values of UA were compared with the theoretical values obtained by DFT method. Nonlinear optical behavior of the unsymmetrical azine is also examined by the theoretically predicted values of dipole moment (μ), polarizability (α0) and first hyperpolarizability (βtot). Stability of the UA molecule has been analyzed using NBO analysis. The electrochemistry of UA studied experimentally by cyclic voltammetry is complemented by the computational analysis of the anionic form of the molecule UA. The determination of various global and local reactivity descriptors in the context of chemical reactivity is also performed and the electrophilicity at the vital atomic sites in UA is revealed. Bader's Atoms in molecules (AIM) theory of UA indicated the presence of intramolecular hydrogen bonding in the molecule. The molecular electrostatic potential (MEP) and HOMO-LUMO orbital analysis are also performed for the molecule UA.

A combined experimental and DFT study of a novel unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine.

PubMed

Vijaya, P; Sankaran, K R

2015-03-05

A novel unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine (UA) was prepared and characterized by IR, (1)H and (13)C NMR spectral studies. A 2D - potential energy scan (PES) of p-isobutylacetophenone (IBAP) was the portal to the conformational analysis of UA by density functional theory (DFT) methods using 6-31G(d,p) basis set by Gaussian 03 program. The theoretical IR frequencies were found to be in good agreement with the experimental values. The IR frequencies of UA were analyzed by means of Potential energy Distribution (PED %) calculation using Vibrational Energy Distribution Analysis (VEDA 4) program. The experimental NMR chemical shift values of UA were compared with the theoretical values obtained by DFT method. Nonlinear optical behavior of the unsymmetrical azine is also examined by the theoretically predicted values of dipole moment (μ), polarizability (α0) and first hyperpolarizability (βtot). Stability of the UA molecule has been analyzed using NBO analysis. The electrochemistry of UA studied experimentally by cyclic voltammetry is complemented by the computational analysis of the anionic form of the molecule UA. The determination of various global and local reactivity descriptors in the context of chemical reactivity is also performed and the electrophilicity at the vital atomic sites in UA is revealed. Bader's Atoms in molecules (AIM) theory of UA indicated the presence of intramolecular hydrogen bonding in the molecule. The molecular electrostatic potential (MEP) and HOMO-LUMO orbital analysis are also performed for the molecule UA. Copyright © 2014 Elsevier B.V. All rights reserved.

Young children's reasoning about the effects of emotional and physiological states on academic performance.

PubMed

Amsterlaw, Jennifer; Lagattuta, Kristin Hansen; Meltzoff, Andrew N

2009-01-01

This study assessed young children's understanding of the effects of emotional and physiological states on cognitive performance. Five, 6-, 7-year-olds, and adults (N= 96) predicted and explained how children experiencing a variety of physiological and emotional states would perform on academic tasks. Scenarios included: (a) negative and positive emotions, (b) negative and positive physiological states, and (c) control conditions. All age groups understood the impairing effects of negative emotions and physiological states. Only 7-year-olds, however, showed adult-like reasoning about the potential enhancing effects of positive internal states and routinely cited cognitive mechanisms to explain how internal states affect performance. These results shed light on theory-of-mind development and also have significance for children's everyday school success.

Leucine/Pd-loaded (5,5) single-walled carbon nanotube matrix as a novel nanobiosensors for in silico detection of protein.

PubMed

Yoosefian, Mehdi; Etminan, Nazanin

2018-06-01

We have designed a novel nanobiosensor for in silico detecting proteins based on leucine/Pd-loaded single-walled carbon nanotube matrix. Density functional theory at the B3LYP/6-31G (d) level of theory was realized to analyze the geometrical and electronic structure of the proposed nanobiosensor. The solvent effects were investigated using the Tomasi's polarized continuum model. Atoms-in-molecules theory was used to study the nature of interactions by calculating the electron density ρ(r) and Laplacian at the bond critical points. Natural bond orbital analysis was performed to achieve a deep understanding of the nature of the interactions. The biosensor has potential application for high sensitive and rapid response to protein due to the chemical adsorption of L-leucine amino acid onto Pd-loaded single-walled carbon nanotube and reactive functional groups that can incorporate in hydrogen binding, hydrophobic interactions and van der Waals forces with the protein surface in detection process.

Parent-child picture-book reading, mothers' mental state language and children's theory of mind.

PubMed

Adrian, Juan E; Clemente, Rosa A; Villanueva, Lidon; Rieffe, Carolien

2005-08-01

This study focuses on parent-child book reading and its connection to the development of a theory of mind. First, parents were asked to report about frequency of parent-child storybook reading at home. Second, mothers were asked to read four picture-books to thirty-four children between 4;0 and 5;0. Both frequency of parent-child storybook reading at home, and mother's use of mental state terms in picture-books reading tasks were significantly associated with success on false belief tasks, after partialling out a number of potential mediators such as age of children, verbal IQ, paternal education, and words used by mothers in joint picture-book reading. Among the different mental state references (cognitive terms, desires, emotions and perceptions), it was found that the frequency and variety of cognitive terms, but also the frequency of emotional terms correlated positively with children's false belief performance. Relationships between mental state language and theory of mind are discussed.

Sensitivity Analysis for Steady State Groundwater Flow Using Adjoint Operators

NASA Astrophysics Data System (ADS)

Sykes, J. F.; Wilson, J. L.; Andrews, R. W.

1985-03-01

Adjoint sensitivity theory is currently being considered as a potential method for calculating the sensitivity of nuclear waste repository performance measures to the parameters of the system. For groundwater flow systems, performance measures of interest include piezometric heads in the vicinity of a waste site, velocities or travel time in aquifers, and mass discharge to biosphere points. The parameters include recharge-discharge rates, prescribed boundary heads or fluxes, formation thicknesses, and hydraulic conductivities. The derivative of a performance measure with respect to the system parameters is usually taken as a measure of sensitivity. To calculate sensitivities, adjoint sensitivity equations are formulated from the equations describing the primary problem. The solution of the primary problem and the adjoint sensitivity problem enables the determination of all of the required derivatives and hence related sensitivity coefficients. In this study, adjoint sensitivity theory is developed for equations of two-dimensional steady state flow in a confined aquifer. Both the primary flow equation and the adjoint sensitivity equation are solved using the Galerkin finite element method. The developed computer code is used to investigate the regional flow parameters of the Leadville Formation of the Paradox Basin in Utah. The results illustrate the sensitivity of calculated local heads to the boundary conditions. Alternatively, local velocity related performance measures are more sensitive to hydraulic conductivities.

An equivalent potential vorticity theory applied to the analysis and prediction of severe storm dynamics

NASA Technical Reports Server (NTRS)

Paine, D. A.; Kaplan, M. L.

1976-01-01

Potential vorticity theory is developed in a description of an equivalent potential temperature topography, and a new theory suited to the description of scale interaction is elaborated. Macroscale triggering of ageostrophic flow fields at the mesoscale, in turn leading to release of convective instability along narrow zones at the microscale, is examined. Correlation of appreciable decrease in potential vorticity with such phenomena as cumulonimbi, tornados, and duststorms is examined. The relevance of a multiscale energy-momentum cascade in numerical prediction of severe mesoscale and microscale phenomena from radiosonde data is reviewed. Hypotheses for mesoscale dynamics are constructed.

Engineering Redox Potential of Lithium Clusters for Electrode Material in Lithium-Ion Batteries

DOE PAGES

Kushwaha, Anoop Kumar; Sahoo, Mihir Ranjan; Nanda, Jagjit; ...

2017-07-01

Low negative electrode potential and high reactivity makes lithium (Li) ideal candidate for obtaining highest possible energy density among other materials. Here, we show a novel route with which the overall electrode potential could significantly be enhanced through selection of cluster size. In using first principles density functional theory and continuum dielectric model, we studied free energy and redox potential as well as investigated relative stability of Li n (n ≤ 8) clusters in both gas phase and solution. We found that Li 3 has the lowest negative redox potential (thereby highest overall electrode potential) suggesting that cluster based approachmore » could provide a novel way of engineering the next generation battery technology. The microscopic origin of Li 3 cluster’s superior performance is related to two major factors: gas phase ionization and difference between solvation free energy for neutral and positive ion. Taken together, our study provides insight into the engineering of redox potential in battery and could stimulate further work in this direction.« less

Engineering Redox Potential of Lithium Clusters for Electrode Material in Lithium-Ion Batteries

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

Kushwaha, Anoop Kumar; Sahoo, Mihir Ranjan; Nanda, Jagjit

Low negative electrode potential and high reactivity makes lithium (Li) ideal candidate for obtaining highest possible energy density among other materials. Here, we show a novel route with which the overall electrode potential could significantly be enhanced through selection of cluster size. In using first principles density functional theory and continuum dielectric model, we studied free energy and redox potential as well as investigated relative stability of Li n (n ≤ 8) clusters in both gas phase and solution. We found that Li 3 has the lowest negative redox potential (thereby highest overall electrode potential) suggesting that cluster based approachmore » could provide a novel way of engineering the next generation battery technology. The microscopic origin of Li 3 cluster’s superior performance is related to two major factors: gas phase ionization and difference between solvation free energy for neutral and positive ion. Taken together, our study provides insight into the engineering of redox potential in battery and could stimulate further work in this direction.« less

High-temperature asymptotics of supersymmetric partition functions

DOE PAGES

Ardehali, Arash Arabi

2016-07-05

We study the supersymmetric partition function of 4d supersymmetric gauge theories with a U(1) R-symmetry on Euclidean S 3 × S β 1, with S 3 the unit-radius squashed three-sphere, and β the circumference of the circle. For superconformal theories, this partition function coincides (up to a Casimir energy factor) with the 4d superconformal index. The partition function can be computed exactly using the supersymmetric localization of the gauge theory path-integral. It takes the form of an elliptic hypergeometric integral, which may be viewed as a matrix-integral over the moduli space of the holonomies of the gauge fields around Smore » β 1. At high temperatures (β → 0, corresponding to the hyperbolic limit of the elliptic hypergeometric integral) we obtain from the matrix-integral a quantum effective potential for the holonomies. The effective potential is proportional to the temperature. Therefore the high-temperature limit further localizes the matrix-integral to the locus of the minima of the potential. If the effective potential is positive semi-definite, the leading high-temperature asymptotics of the partition function is given by the formula of Di Pietro and Komargodski, and the subleading asymptotics is connected to the Coulomb branch dynamics on R 3 × S 1. In theories where the effective potential is not positive semi-definite, the Di Pietro-Komargodski formula needs to be modified. In particular, this modification occurs in the SU(2) theory of Intriligator-Seiberg-Shenker, and the SO(N) theory of Brodie-Cho-Intriligator, both believed to exhibit “misleading” anomaly matchings, and both believed to yield interacting superconformal field theories with c < a. Lastly, two new simple tests for dualities between 4d supersymmetric gauge theories emerge as byproducts of our analysis.« less

The Effects of Anti-Vaccine Conspiracy Theories on Vaccination Intentions

PubMed Central

Jolley, Daniel; Douglas, Karen M.

2014-01-01

The current studies investigated the potential impact of anti-vaccine conspiracy beliefs, and exposure to anti-vaccine conspiracy theories, on vaccination intentions. In Study 1, British parents completed a questionnaire measuring beliefs in anti-vaccine conspiracy theories and the likelihood that they would have a fictitious child vaccinated. Results revealed a significant negative relationship between anti-vaccine conspiracy beliefs and vaccination intentions. This effect was mediated by the perceived dangers of vaccines, and feelings of powerlessness, disillusionment and mistrust in authorities. In Study 2, participants were exposed to information that either supported or refuted anti-vaccine conspiracy theories, or a control condition. Results revealed that participants who had been exposed to material supporting anti-vaccine conspiracy theories showed less intention to vaccinate than those in the anti-conspiracy condition or controls. This effect was mediated by the same variables as in Study 1. These findings point to the potentially detrimental consequences of anti-vaccine conspiracy theories, and highlight their potential role in shaping health-related behaviors. PMID:24586574

The effects of anti-vaccine conspiracy theories on vaccination intentions.

PubMed

Jolley, Daniel; Douglas, Karen M

2014-01-01

The current studies investigated the potential impact of anti-vaccine conspiracy beliefs, and exposure to anti-vaccine conspiracy theories, on vaccination intentions. In Study 1, British parents completed a questionnaire measuring beliefs in anti-vaccine conspiracy theories and the likelihood that they would have a fictitious child vaccinated. Results revealed a significant negative relationship between anti-vaccine conspiracy beliefs and vaccination intentions. This effect was mediated by the perceived dangers of vaccines, and feelings of powerlessness, disillusionment and mistrust in authorities. In Study 2, participants were exposed to information that either supported or refuted anti-vaccine conspiracy theories, or a control condition. Results revealed that participants who had been exposed to material supporting anti-vaccine conspiracy theories showed less intention to vaccinate than those in the anti-conspiracy condition or controls. This effect was mediated by the same variables as in Study 1. These findings point to the potentially detrimental consequences of anti-vaccine conspiracy theories, and highlight their potential role in shaping health-related behaviors.

On the Numerical Analysis of Decay Rate Enhancement in Metallic Environment

NASA Astrophysics Data System (ADS)

Mehedinteanu, S.

2007-10-01

Motivated on the very recent experiments to determine the acceleration of the alpha decay of meta-stable radionuclides in metallic environment some work has been done to strengthten the importance in the process of electrons screening in metals. Thus, by combining the Gamow decay theory with electrostatic screening in Debye-Hückel approximation (jellium model) a formula for ``the shift'' in screening energy which enters in the decay enhancement factor expression that copes well with these experiments has been derived. It was established that to simulate the poly-atoms system containing decaying isotopes in QM&MD codes calculations, and to include ``the screening energy shift'' of protons, decay alpha, beta+ particles due to all surrounding interacting effects, it is sufficiently only to substitute the code ruly pseudo-potential input for hydrogen-like atoms (including alpha) by a screened Coulomb potential as from the well-known Gamow alpha decay theory. For demonstration is used the QM&MD code package which usually performs density-functional theory (DFT) total-energy calculations for materials ranging from insulators to transition metals. This package employs first-principles pseudo-potentials and a plane-wave basis-set, and it was used to do a special calculus for some metal environments (Pd) where protons-deuterons are implanted or when it is alloyed with a radionuclide-like isotopes (174Hf72), the results compare well with the existing experiments on the decay enhancement. These works give further arguments for a cheap solution to remove the transuranic waste (involving all alpha-decay) of used-up rods of fission reactors in a time period of a few years.

A pressure consistent bridge correction of Kovalenko-Hirata closure in Ornstein-Zernike theory for Lennard-Jones fluids by apparently adjusting sigma parameter

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

Ebato, Yuki; Miyata, Tatsuhiko, E-mail: miyata.tatsuhiko.mf@ehime-u.ac.jp

Ornstein-Zernike (OZ) integral equation theory is known to overestimate the excess internal energy, U{sup ex}, pressure through the virial route, P{sub v}, and excess chemical potential, μ{sup ex}, for one-component Lennard-Jones (LJ) fluids under hypernetted chain (HNC) and Kovalenko-Hirata (KH) approximatons. As one of the bridge correction methods to improve the precision of these thermodynamic quantities, it was shown in our previous paper that the method to apparently adjust σ parameter in the LJ potential is effective [T. Miyata and Y. Ebato, J. Molec. Liquids. 217, 75 (2016)]. In our previous paper, we evaluated the actual variation in the σmore » parameter by using a fitting procedure to molecular dynamics (MD) results. In this article, we propose an alternative method to determine the actual variation in the σ parameter. The proposed method utilizes a condition that the virial and compressibility pressures coincide with each other. This method can correct OZ theory without a fitting procedure to MD results, and possesses characteristics of keeping a form of HNC and/or KH closure. We calculate the radial distribution function, pressure, excess internal energy, and excess chemical potential for one-component LJ fluids to check the performance of our proposed bridge function. We discuss the precision of these thermodynamic quantities by comparing with MD results. In addition, we also calculate a corrected gas-liquid coexistence curve based on a corrected KH-type closure and compare it with MD results.« less

Theory-of-mind development influences suggestibility and source monitoring.

PubMed

Bright-Paul, Alexandra; Jarrold, Christopher; Wright, Daniel B

2008-07-01

According to the mental-state reasoning model of suggestibility, 2 components of theory of mind mediate reductions in suggestibility across the preschool years. The authors examined whether theory-of-mind performance may be legitimately separated into 2 components and explored the memory processes underlying the associations between theory of mind and suggestibility, independent of verbal ability. Children 3 to 6 years old completed 6 theory-of-mind tasks and a postevent misinformation procedure. Contrary to the model's prediction, a single latent theory-of-mind factor emerged, suggesting a single-component rather than a dual-component conceptualization of theory-of-mind performance. This factor provided statistical justification for computing a single composite theory-of-mind score. Improvements in theory of mind predicted reductions in suggestibility, independent of verbal ability (Study 1, n = 72). Furthermore, once attribution biases were controlled (Study 2, n = 45), there was also a positive relationship between theory of mind and source memory, but not recognition performance. The findings suggest a substantial, and possibly causal, association between theory-of-mind development and resistance to suggestion, driven specifically by improvements in source monitoring.

Assessment of learning powered mobility use--applying grounded theory to occupational performance.

PubMed

Nilsson, Lisbeth; Durkin, Josephine

2014-01-01

Collaboration by two grounded theory researchers, who each had developed a learning continuum instrument, led to the emergence of a new tool for assessment of learning powered mobility use. We undertook a rigorous process of comparative reanalysis that included merging, modifying, and expanding our previous research findings. A new instrument together with its facilitating strategies emerged in the course of revisits to our existing rich account of data taken from real environment powered mobility practice over an extensive time period. Instrument descriptors, categories, phases, and stages allow a facilitator to assess actual phase and plot actual occupational performance and provide a learner with the just right challenge through the learning process. Facilitating strategies are described for each of the phases and provide directions for involvement during learner performance. The learning approach is led by a belief system that the intervention is user-led, working in partnership and empowering the learner. The new assessment tool is inclusive of every potential powered mobility user because it focuses on the whole continuum of the learning process of powered mobility use from novice to expert. The new tool was appraised by clinicians and has been used successfully in clinical practice in the United Kingdom and Sweden.

The proprietary hospital industry: a financial analysis 1972-1982.

PubMed

Michel, A; Shaked, I; Daley, J

1985-01-01

This paper evaluates the performance of both specific firms within the American for-profit hospital industry and the industry as a whole. First, traditional financial analysis is used to evaluate individual publicly traded for-profit chains. Then, industry performance from 1973 to 1982 is evaluated using a set of measures based on Modern Portfolio Theory. The traditional financial analysis indicates that the industry seems increasingly profitable as well as increasingly healthy from the perspective of utilizing its assets and reducing its collection period. However, the industry's rapid growth rate has strained its ability to use additional debt funding and has created a potentially dangerous liquidity position. Measures based on Modern Portfolio Theory indicate that the average return of the industry has improved over the past 5 years. However, its risk has also increased. Nevertheless, the increase in risk is more than offset by the increased average return. In addition, recent legislation designed 'to reward the efficient' has introduced a significant degree of uncertainty into the industry's performance for the coming years. Thus, hospitals' ability to maintain the substantial profitability and rate of growth they have experienced over the past decade will depend on how well they will adapt to the changing environment.

Anxiety, anticipation and contextual information: A test of attentional control theory.

PubMed

Cocks, Adam J; Jackson, Robin C; Bishop, Daniel T; Williams, A Mark

2016-09-01

We tested the assumptions of Attentional Control Theory (ACT) by examining the impact of anxiety on anticipation using a dynamic, time-constrained task. Moreover, we examined the involvement of high- and low-level cognitive processes in anticipation and how their importance may interact with anxiety. Skilled and less-skilled tennis players anticipated the shots of opponents under low- and high-anxiety conditions. Participants viewed three types of video stimuli, each depicting different levels of contextual information. Performance effectiveness (response accuracy) and processing efficiency (response accuracy divided by corresponding mental effort) were measured. Skilled players recorded higher levels of response accuracy and processing efficiency compared to less-skilled counterparts. Processing efficiency significantly decreased under high- compared to low-anxiety conditions. No difference in response accuracy was observed. When reviewing directional errors, anxiety was most detrimental to performance in the condition conveying only contextual information, suggesting that anxiety may have a greater impact on high-level (top-down) cognitive processes, potentially due to a shift in attentional control. Our findings provide partial support for ACT; anxiety elicited greater decrements in processing efficiency than performance effectiveness, possibly due to predominance of the stimulus-driven attentional system.

Development of modularity in the neural activity of childrenʼs brains

NASA Astrophysics Data System (ADS)

Chen, Man; Deem, Michael W.

2015-02-01

We study how modularity of the human brain changes as children develop into adults. Theory suggests that modularity can enhance the response function of a networked system subject to changing external stimuli. Thus, greater cognitive performance might be achieved for more modular neural activity, and modularity might likely increase as children develop. The value of modularity calculated from functional magnetic resonance imaging (fMRI) data is observed to increase during childhood development and peak in young adulthood. Head motion is deconvolved from the fMRI data, and it is shown that the dependence of modularity on age is independent of the magnitude of head motion. A model is presented to illustrate how modularity can provide greater cognitive performance at short times, i.e. task switching. A fitness function is extracted from the model. Quasispecies theory is used to predict how the average modularity evolves with age, illustrating the increase of modularity during development from children to adults that arises from selection for rapid cognitive function in young adults. Experiments exploring the effect of modularity on cognitive performance are suggested. Modularity may be a potential biomarker for injury, rehabilitation, or disease.

Talent identification and specialization in sport: an overview of some unanswered questions.

PubMed

Gonçalves C, E B; Rama L, M L; Figueiredo, António B

2012-12-01

The theory of deliberate practice postulates that experts are always made, not born. This theory translated to the youth-sport domain means that if athletes want to be high-level performers, they need to deliberately engage in practice during the specialization years, spending time wisely and always focusing on tasks that challenge current performance. Sport organizations in several countries around the world created specialized training centers where selected young talents practice under the supervision of experienced coaches in order to become professional athletes and integrate onto youth national teams. Early specialization and accurate observation by expert coaches or scouts remain the only tools to find a potential excellent athlete among a great number of participants. In the current study, the authors present 2 of the problems raised by talent search and the risks of such a search. Growth and maturation are important concepts to better understand the identification, selection, and development processes of young athletes. However, the literature suggests that sport-promoting strategies are being maintained despite the increased demands in the anthropometric characteristics of professional players and demands of actual professional soccer competitions. On the other hand, identifying biological variables that can predict performance is almost impossible.

Destination memory and cognitive theory of mind in normal ageing.

PubMed

El Haj, Mohamad; Raffard, Stéphane; Gély-Nargeot, Marie-Christine

2016-01-01

Destination memory is the ability to remember the destination to which a piece of information has been addressed (e.g., "Did I tell you about the promotion?"). This ability is found to be impaired in normal ageing. Our work aimed to link this deterioration to the decline in theory of mind. Forty younger adults (M age = 23.13 years, SD = 4.00) and 36 older adults (M age = 69.53 years, SD = 8.93) performed a destination memory task. They also performed the False-belief test addressing cognitive theory of mind and the Reading the mind in the eyes test addressing affective theory of mind. Results showed significant deterioration in destination memory, cognitive theory of mind and affective theory of mind in the older adults. The older adults' performance on destination memory was significantly correlated with and predicted by their performance on cognitive theory of mind. Difficulties in the ability to interpret and predict others' mental states are related to destination memory decline in older adults.

Pair potentials for liquid sodium near freezing from electron theory and from inversion of the measured structure factor

NASA Astrophysics Data System (ADS)

Perrot, F.; March, N. H.

An effective pair potential for liquid sodium near freezing has been calculated from electron theory using the density-functional method. The main features of the potential extracted by Reatto, Levesque, and Weis [phys. Rev. A 33, 3451 (1986)] by inverting the measured structure factor of Greenfield, Wellendorf, and Wiser [Phys. Rev. A 4, 1607 (1971)] are faithfully reflected by electron theory. To obtain precise agreement between the two methods will evidently require further progress in setting up nonlocal exchange and correlation functionals.

Store manager performance and satisfaction: effects on store employee performance and satisfaction, store customer satisfaction, and store customer spending growth.

PubMed

Netemeyer, Richard G; Maxham, James G; Lichtenstein, Donald R

2010-05-01

Based on emotional contagion theory and the value-profit chain literatures, the present study posits a number of hypotheses that show how managers in the small store, small number of employees retail context may affect store employees, customers, and potentially store performance. With data from 306 store managers, 1,615 store customer-contact employees, and 57,656 customers of a single retail chain, the authors examined relationships among store manager job satisfaction and job performance, store customer-contact employee job satisfaction and job performance, customer satisfaction with the retailer, and a customer-spending-based store performance metric (customer spending growth over a 2-year period). Via path analysis, several hypothesized direct and interaction relations among these constructs are supported. The results suggest implications for academic researchers and retail managers. PsycINFO Database Record (c) 2010 APA, all rights reserved.

When Task Conflict Becomes Personal: The Impact of Perceived Team Performance.

PubMed

Guenter, Hannes; van Emmerik, Hetty; Schreurs, Bert; Kuypers, Tom; van Iterson, Ad; Notelaers, Guy

2016-10-01

Although potentially beneficial, task conflict may threaten teams because it often leads to relationship conflict. Prior research has identified a set of interpersonal factors (e.g., team communication, team trust) that help attenuate this association. The purpose of this article is to provide an alternative perspective that focuses on the moderating role of performance-related factors (i.e., perceived team performance). Using social identity theory, we build a model that predicts how task conflict associates with growth in relationship conflict and how perceived team performance influences this association. We test a three-wave longitudinal model by means of random coefficient growth modeling, using data from 60 ongoing teams working in a health care organization. Results provide partial support for our hypotheses. Only when perceived team performance is low, do task conflicts relate with growth in relationship conflict. We conclude that perceived team performance seems to enable teams to uncouple task from relationship conflict.

Direct water decomposition on transition metal surfaces: Structural dependence and catalytic screening

DOE PAGES

Tsai, Charlie; Lee, Kyoungjin; Yoo, Jong Suk; ...

2016-02-16

Density functional theory calculations are used to investigate thermal water decomposition over the close-packed (111), stepped (211), and open (100) facets of transition metal surfaces. A descriptor-based approach is used to determine that the (211) facet leads to the highest possible rates. As a result, a range of 96 binary alloys were screened for their potential activity and a rate control analysis was performed to assess how the overall rate could be improved.

The Effects of Motivation on Student Performance on Science Assessments

NASA Astrophysics Data System (ADS)

Glenn, Tina Heard

Academic achievement of public school students in the United States has significantly fallen behind other countries. Students' lack of knowledge of, or interest in, basic science and math has led to fewer graduates of science, technology, engineering, and math-related fields (STEM), a factor that may affect their career success and will certainly affect the numbers in the workforce who are prepared for some STEM jobs. Drawing from self-determination theory and achievement theory, the purpose of this correlational study was to determine whether there were significant relationships between high school academic performance in science classes, motivations (self-efficacy, self-regulation, and intrinsic and extrinsic goal orientation), and academic performance in an introductory online college biology class. Data were obtained at 2 points in time from a convenience multiethnic sample of adult male ( n =16) and female (n = 49) community college students in the southeast United States. Correlational analyses indicated no statistically significant relationships for intrinsic or extrinsic goal orientation, self-efficacy, or self-regulation with high school science mean-GPA nor college biology final course grade. However, high school academic performance in science classes significantly predicted college performance in an entry-level online biology class. The implications of positive social change include knowledge useful for educational institutions to explore additional factors that may motivate students to enroll in science courses, potentially leading to an increase in scientific knowledge and STEM careers.

The Development of Attention Systems and Working Memory in Infancy

PubMed Central

Reynolds, Greg D.; Romano, Alexandra C.

2016-01-01

In this article, we review research and theory on the development of attention and working memory in infancy using a developmental cognitive neuroscience framework. We begin with a review of studies examining the influence of attention on neural and behavioral correlates of an earlier developing and closely related form of memory (i.e., recognition memory). Findings from studies measuring attention utilizing looking measures, heart rate, and event-related potentials (ERPs) indicate significant developmental change in sustained and selective attention across the infancy period. For example, infants show gains in the magnitude of the attention related response and spend a greater proportion of time engaged in attention with increasing age (Richards and Turner, 2001). Throughout infancy, attention has a significant impact on infant performance on a variety of tasks tapping into recognition memory; however, this approach to examining the influence of infant attention on memory performance has yet to be utilized in research on working memory. In the second half of the article, we review research on working memory in infancy focusing on studies that provide insight into the developmental timing of significant gains in working memory as well as research and theory related to neural systems potentially involved in working memory in early development. We also examine issues related to measuring and distinguishing between working memory and recognition memory in infancy. To conclude, we discuss relations between the development of attention systems and working memory. PMID:26973473

Capacitive Energy Extraction by Few-Layer Graphene Electrodes

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

Lian, Cheng; Zhan, Cheng; Jiang, De-en

Capacitive double-layer expansion is a promising technology to harvest energy arising from the salinity difference between freshwater and seawater. Its optimal performance requires a careful selection of the operation potentials and electrode materials. While carbonaceous materials such as graphene and various forms of activated carbons are routinely used as the electrodes, there is little knowledge on how the quantum capacitance and the electric double-layer (EDL) capacitance, which are on the same order of magnitude, affect the capacitive performance. Toward understanding that from a theoretical perspective, here we study the capacitive energy extraction with graphene electrodes as a function of themore » number of graphene layers. The classical density functional theory is joined with the electronic density functional theory to obtain the EDL and the quantum capacitance, respectively. The theoretical results show that the quantum capacitance contribution plays a dominant role in extracting energy using the single-layer graphene, but its effect diminishes as the number of graphene layers increases. The overall extracted energy is dominated by the EDL contribution beyond about four graphene layers. Electrodes with more graphene layers are able to extract more energy at low charging potential. Here, because many porous carbons have nanopores with stacked graphene layers, our theoretical predictions are useful to identify optimal operation parameters for capacitive energy extraction with porous electrodes of different wall thickness.« less

Capacitive Energy Extraction by Few-Layer Graphene Electrodes

DOE PAGES

Lian, Cheng; Zhan, Cheng; Jiang, De-en; ...

2017-06-09

Capacitive double-layer expansion is a promising technology to harvest energy arising from the salinity difference between freshwater and seawater. Its optimal performance requires a careful selection of the operation potentials and electrode materials. While carbonaceous materials such as graphene and various forms of activated carbons are routinely used as the electrodes, there is little knowledge on how the quantum capacitance and the electric double-layer (EDL) capacitance, which are on the same order of magnitude, affect the capacitive performance. Toward understanding that from a theoretical perspective, here we study the capacitive energy extraction with graphene electrodes as a function of themore » number of graphene layers. The classical density functional theory is joined with the electronic density functional theory to obtain the EDL and the quantum capacitance, respectively. The theoretical results show that the quantum capacitance contribution plays a dominant role in extracting energy using the single-layer graphene, but its effect diminishes as the number of graphene layers increases. The overall extracted energy is dominated by the EDL contribution beyond about four graphene layers. Electrodes with more graphene layers are able to extract more energy at low charging potential. Here, because many porous carbons have nanopores with stacked graphene layers, our theoretical predictions are useful to identify optimal operation parameters for capacitive energy extraction with porous electrodes of different wall thickness.« less

Linking Science Analysis with Observation Planning: A Full Circle Data Lifecycle

NASA Technical Reports Server (NTRS)

Grosvenor, Sandy; Jones, Jeremy; Koratkar, Anuradha; Li, Connie; Mackey, Jennifer; Neher, Ken; Wolf, Karl; Obenschain, Arthur F. (Technical Monitor)

2001-01-01

A clear goal of the Virtual Observatory (VO) is to enable new science through analysis of integrated astronomical archives. An additional and powerful possibility of the VO is to link and integrate these new analyses with planning of new observations. By providing tools that can be used for observation planning in the VO, the VO will allow the data lifecycle to come full circle: from theory to observations to data and back around to new theories and new observations. The Scientist's Expert Assistant (SEA) Simulation Facility (SSF) is working to combine the ability to access existing archives with the ability to model and visualize new observations. Integrating the two will allow astronomers to better use the integrated archives of the VO to plan and predict the success of potential new observations more efficiently, The full circle lifecycle enabled by SEA can allow astronomers to make substantial leaps in the quality of data and science returns on new observations. Our paper examines the exciting potential of integrating archival analysis with new observation planning, such as performing data calibration analysis on archival images and using that analysis to predict the success of new observations, or performing dynamic signal-to-noise analysis combining historical results with modeling of new instruments or targets. We will also describe how the development of the SSF is progressing and what have been its successes and challenges.

Linking Science Analysis with Observation Planning: A Full Circle Data Lifecycle

NASA Technical Reports Server (NTRS)

Jones, Jeremy; Grosvenor, Sandy; Wolf, Karl; Li, Connie; Koratkar, Anuradha; Powers, Edward I. (Technical Monitor)

2001-01-01

A clear goal of the Virtual Observatory (VO) is to enable new science through analysis of integrated astronomical archives. An additional and powerful possibility of the VO is to link and integrate these new analyses with planning of new observations. By providing tools that can be used for observation planning in the VO, the VO will allow the data lifecycle to come full circle: from theory to observations to data and back around to new theories and new observations. The Scientist's Expert Assistant (SEA) Simulation Facility (SSF) is working to combine the ability to access existing archives with the ability to model and visualize new observations. Integrating the two will allow astronomers to better use the integrated archives of the VO to plan and predict the success of potential new observations. The full circle lifecycle enabled by SEA can allow astronomers to make substantial leaps in the quality of data and science returns on new observations. Our paper will examine the exciting potential of integrating archival analysis with new observation planning, such as performing data calibration analysis on archival images and using that analysis to predict the success of new observations, or performing dynamic signal-to-noise analysis combining historical results with modeling of new instruments or targets. We will also describe how the development of the SSF is progressing and what has been its successes and challenges.

A theoretical study on the electronic structures and equilibrium constants evaluation of Deferasirox iron complexes.

PubMed

Salehi, Samie; Saljooghi, Amir Shokooh; Izadyar, Mohammad

2016-10-01

Elemental iron is essential for cellular growth and homeostasis but it is potentially toxic to the cells and tissues. Excess iron can contribute in tumor initiation and tumor growth. Obviously, in iron overload issues using an iron chelator in order to reduce iron concentration seems to be vital. This study presents the density functional theory calculations of the electronic structure and equilibrium constant for iron-deferasirox (Fe-DFX) complexes in the gas phase, water and DMSO. A comprehensive study was performed to investigate the Deferasirox-iron complexes in chelation therapy. Calculation was performed in CAMB3LYP/6-31G(d,p) to get the optimized structures for iron complexes in high and low spin states. Natural bond orbital and quantum theory of atoms in molecules analyses was carried out with B3LYP/6-311G(d,p) to understand the nature of complex bond character and electronic transition in complexes. Electrostatic potential effects on the complexes were evaluated using the CHelpG calculations. The results indicated that higher affinity for Fe(III) is not strictly a function of bond length but also the degree of Fe-X (X=O,N) covalent bonding. Based on the quantum reactivity parameters which have been investigated here, it is possible reasonable design of the new chelators to improve the chelator abilities. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Development of Attention Systems and Working Memory in Infancy.

PubMed

Reynolds, Greg D; Romano, Alexandra C

2016-01-01

In this article, we review research and theory on the development of attention and working memory in infancy using a developmental cognitive neuroscience framework. We begin with a review of studies examining the influence of attention on neural and behavioral correlates of an earlier developing and closely related form of memory (i.e., recognition memory). Findings from studies measuring attention utilizing looking measures, heart rate, and event-related potentials (ERPs) indicate significant developmental change in sustained and selective attention across the infancy period. For example, infants show gains in the magnitude of the attention related response and spend a greater proportion of time engaged in attention with increasing age (Richards and Turner, 2001). Throughout infancy, attention has a significant impact on infant performance on a variety of tasks tapping into recognition memory; however, this approach to examining the influence of infant attention on memory performance has yet to be utilized in research on working memory. In the second half of the article, we review research on working memory in infancy focusing on studies that provide insight into the developmental timing of significant gains in working memory as well as research and theory related to neural systems potentially involved in working memory in early development. We also examine issues related to measuring and distinguishing between working memory and recognition memory in infancy. To conclude, we discuss relations between the development of attention systems and working memory.

Correlation between theoretical descriptor and catalytic oxygen reduction activity of graphene supported palladium and palladium alloy electrocatalysts

NASA Astrophysics Data System (ADS)

Seo, Min Ho; Choi, Sung Mook; Lee, Dong Un; Kim, Won Bae; Chen, Zhongwei

2015-12-01

The oxygen reduction reaction, ORR, performances of graphene-supported palladium (Pd) and palladium alloys (Pd3X: X = Ag, Co and Fe) catalysts with highly dispersed catalyst particles are investigated in acidic and alkaline conditions using a rotating disk electrode, RDE. Graphene nanosheet, GNS, supported Pd based catalysts are fabricated without surfactant through the impregnation of Pd and 2nd metal precursors on GNS, leading to small and uniformly dispersed nanoparticles, even when high metal loading of up to 60 wt.% are deposited on supports. The ab-initio density functional theory, DFT, calculations, which are based on the d-band center theory, have been applied to correlate with the results of the ORR performances obtained by half-cell tests. Additionally, the cohesive energy, Ecoh, and dissolution potential, Um, for the Pd nanoparticles have been calculated to understand thermodynamic stability. To elucidate the d-band center shift, the Pd 3d5/2 core-level binding energies for Pd/GNS, Pd3Ag/GNS, Pd3Fe/GNS and Pd3Co/GNS have been investigated by X-ray photoelectron spectroscopy, XPS. The GNS-supported Pd, or Pd-based alloy-nanoparticle catalyst shows good ORR activity under acidic and alkaline conditions, suggesting it may offer potential replacement for Pt for use in cathode electrodes of anion-exchange membrane fuel cell, AEMFC, and acid based polymer electrolyte fuel cell, PEMFC.

Nonadiabatic dynamics on the two coupled electronic PESs: the H+ + O2 system.

PubMed

Xavier, F George D

2010-09-30

Multistate adiabatic and diabatic PESs were computed for the H+ + O2 collision system in Jacobi coordinates, (R,r,γ) using the cc-pVTZ basis set and the ic-MRCI level of theory. In addition, all possible interaction potentials and nonadiabatic coupling matrix elements among those different electronic states were also computed. Comparisons with earlier computed interaction potentials were made wherever possible, and the differences between them is attributed to the multistate diabatization and the chosen level of theory and basis set. Focusing our attention on the ground-state (GS) and the first excited-state (ES) PES, quantum dynamics were performed using the 2 × 2 diabatic potential submatrix obtained from the multistate (four) diabatic potential matrix within the VCC-RIOSA scheme at two experimentally reported collision energies, E(cm) = 9.5 and 23 eV. The scattering quantities were computed for two experimentally observed collision processes, namely, the inelastic vibrational excitation (IVE), H+ + O2 (X3Σg(−),v = 0) → H+ + O2 (X3Σg(−),v′), and the vibrational charge transfer (VCT), H+ + O2 (X3Σg(−),v = 0) → H (2S) + O (X2Πg,v′′). Comparisons were made with experimental results and found an overall improvement relative to the earlier computed results, and the discrepancies, if any, could be brought down to minimum by further modification in employed ab initio PESs and the interaction potential.

Locating and applying sociological theories of risk-taking to develop public health interventions for adolescents

PubMed Central

Pound, Pandora; Campbell, Rona

2015-01-01

Sociological theories seldom inform public health interventions at the community level. The reasons for this are unclear but may include difficulties in finding, understanding or operationalising theories. We conducted a study to explore the feasibility of locating sociological theories within a specific field of public health, adolescent risk-taking, and to consider their potential for practical application. We identified a range of sociological theories. These explained risk-taking: (i) as being due to lack of social integration; (ii) as a consequence of isolation from mainstream society; (iii) as a rite of passage; (iv) as a response to social constraints; (v) as resistance; (vi) as an aspect of adolescent development; (vii) by the theory of the ‘habitus’; (viii) by situated rationality and social action theories; and (ix) as social practice. We consider these theories in terms of their potential to inform public health interventions for young people. PMID:25999784

Intelligence, personality, and interests: evidence for overlapping traits.

PubMed

Ackerman, P L; Heggestad, E D

1997-03-01

The authors review the development of the modern paradigm for intelligence assessment and application and consider the differentiation between intelligence-as-maximal performance and intelligence-as-typical performance. They review theories of intelligence, personality, and interest as a means to establish potential overlap. Consideration of intelligence-as-typical performance provides a basis for evaluation of intelligence-personality and intelligence-interest relations. Evaluation of relations among personality constructs, vocational interests, and intellectual abilities provides evidence for communality across the domains of personality of J. L. Holland's (1959) model of vocational interests. The authors provide an extensive meta-analysis of personality-intellectual ability correlations, and a review of interest-intellectual ability associations. They identify 4 trait complexes: social, clerical/conventional, science/math, and intellectual/cultural.

Reflection: moving from a mandatory ritual to meaningful professional development.

PubMed

Murdoch-Eaton, Deborah; Sandars, John

2014-03-01

Reflection has become established as a key principle underpinning maintenance of standards within professional education and practice. A requirement to evidence reflection within performance review is intended to develop a transformative approach to practice, identify developmental goals, and ultimately, improve healthcare. However, some applications have taken an excessively instrumental approach to the evidencing of reflection, and while they have provided useful templates or framing devices for recording individualistic reflective practice, they potentially have distorted the original intentions. This article revisits the educational theory underpinning the importance of reflection for enhancing performance and considers how to enhance its value within current paediatric practice.

Limiting of microjoule femtosecond pulses in air-guided modes of a hollow photonic-crystal fiber

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

Konorov, S.O.; Serebryannikov, E.E.; Sidorov-Biryukov, D.A.

Self-phase-modulation-induced spectral broadening of laser pulses in air-guided modes of hollow photonic-crystal fibers (PCFs) is shown to allow the creation of fiber-optic limiters for high-intensity ultrashort laser pulses. The performance of PCF limiters is analyzed in terms of elementary theory of self-phase modulation. Experiments performed with 100 fs microjoule pulses of 800 nm Ti:sapphire laser radiation demonstrate the potential of hollow PCFs as limiters for 10 MW ultrashort laser pulses and show the possibility to switch the limiting level of output radiation energy by guiding femtosecond pulses in different PCF modes.

The force distribution probability function for simple fluids by density functional theory.

PubMed

Rickayzen, G; Heyes, D M

2013-02-28

Classical density functional theory (DFT) is used to derive a formula for the probability density distribution function, P(F), and probability distribution function, W(F), for simple fluids, where F is the net force on a particle. The final formula for P(F) ∝ exp(-AF(2)), where A depends on the fluid density, the temperature, and the Fourier transform of the pair potential. The form of the DFT theory used is only applicable to bounded potential fluids. When combined with the hypernetted chain closure of the Ornstein-Zernike equation, the DFT theory for W(F) agrees with molecular dynamics computer simulations for the Gaussian and bounded soft sphere at high density. The Gaussian form for P(F) is still accurate at lower densities (but not too low density) for the two potentials, but with a smaller value for the constant, A, than that predicted by the DFT theory.

Design of Fresnel Lens-Type Multi-Trapping Acoustic Tweezers

PubMed Central

Tu, You-Lin; Chen, Shih-Jui; Hwang, Yean-Ren

2016-01-01

In this paper, acoustic tweezers which use beam forming performed by a Fresnel zone plate are proposed. The performance has been demonstrated by finite element analysis, including the acoustic intensity, acoustic pressure, acoustic potential energy, gradient force, and particle distribution. The acoustic tweezers use an ultrasound beam produced by a lead zirconate titanate (PZT) transducer operating at 2.4 MHz and 100 Vpeak-to-peak in a water medium. The design of the Fresnel lens (zone plate) is based on air reflection, acoustic impedance matching, and the Fresnel half-wave band (FHWB) theory. This acoustic Fresnel lens can produce gradient force and acoustic potential wells that allow the capture and manipulation of single particles or clusters of particles. Simulation results strongly indicate a good trapping ability, for particles under 150 µm in diameter, in the minimum energy location. This can be useful for cell or microorganism manipulation. PMID:27886050

DFT-derived reactive potentials for the simulation of activated processes: the case of CdTe and CdTe:S.

PubMed

Hu, Xiao Liang; Ciaglia, Riccardo; Pietrucci, Fabio; Gallet, Grégoire A; Andreoni, Wanda

2014-06-19

We introduce a new ab initio derived reactive potential for the simulation of CdTe within density functional theory (DFT) and apply it to calculate both static and dynamical properties of a number of systems (bulk solid, defective structures, liquid, surfaces) at finite temperature. In particular, we also consider cases with low sulfur concentration (CdTe:S). The analysis of DFT and classical molecular dynamics (MD) simulations performed with the same protocol leads to stringent performance tests and to a detailed comparison of the two schemes. Metadynamics techniques are used to empower both Car-Parrinello and classical molecular dynamics for the simulation of activated processes. For the latter, we consider surface reconstruction and sulfur diffusion in the bulk. The same procedures are applied using previously proposed force fields for CdTe and CdTeS materials, thus allowing for a detailed comparison of the various schemes.

Optical fiber sensors and signal processing for intelligent structure monitoring

NASA Technical Reports Server (NTRS)

Rogowski, Robert; Claus, R. O.; Lindner, D. K.; Thomas, Daniel; Cox, Dave

1988-01-01

The analytic and experimental performance of optical fiber sensors for the control of vibration of large aerospace and other structures are investigated. In particular, model domain optical fiber sensor systems, are being studied due to their apparent potential as distributed, low mass sensors of vibration over appropriate ranges of both low frequency and low amplitude displacements. Progress during the past three months is outlined. Progress since September is divided into work in the areas of experimental hardware development, analytical analysis, control design and sensor development. During the next six months, tests of a prototype closed-loop control system for a beam are planned which will demonstrate the solution of several optical fiber instrumentation device problems, the performance of the control system theory which incorporates the model of the modal domain sensor, and the potential for distributed control which this sensor approach offers.

Optical spectra and band structure of Ag(x)Ga(x)Ge(1-x)Se2 (x = 0.333, 0.250, 0.200, 0.167) single crystals: experiment and theory.

PubMed

Reshak, A H; Parasyuk, O V; Fedorchuk, A O; Kamarudin, H; Auluck, S; Chyský, J

2013-12-05

Theoretical and experimental studies of the Ag(x)Ga(x)Ge(1-x)Se2 (x = 0.333, 0.250, 0.200, 0.167) single crystals are performed. These crystals possess a lot of intrinsic defects which are responsible for their optoelectronic features. The theoretical investigations were performed by means of DFT calculations using different exchange-correlation potentials. The experimental studies were carried out using the modulated VUV ellipsometry for dielectric constants and birefringence studies. The comparison of the structure obtained from X-ray with the theoretically optimized structure is presented. The crucial role of the intrinsic defect states is manifested in the choice of the exchange correlation potential used. The data may be applicable for a large number of the ternary chalcogenides which are sensitive to the presence of the local disordered states near the band edges.

Asymptotic quantum elastic generalized Lorenz Mie theory

NASA Astrophysics Data System (ADS)

Gouesbet, G.

2006-10-01

The (electromagnetic) generalized Lorenz-Mie theory describes the interaction between an electromagnetic arbitrary shaped beam and a homogeneous sphere. It is a generalization of the Lorenz-Mie theory which deals with the simpler case of a plane-wave illumination. In a recent paper, we established that, if we restrict ourselves to the study of cross-sections, both for elastic and inelastic scatterings, a macroscopic sphere in Lorenz-Mie theory is formally equivalent to a quantum-like radial potential. To generalize this result, a prerequisite is to possess an asymptotic quantum generalized Lorenz-Mie theory expressing cross-sections in the case of a quantum radial potential interacting with a sub-class of quantum arbitrary wave-packets. Such a theory, restricted however to elastic scattering, is presented in this paper.

Vibrational spectroscopic investigation of p-, m- and o-nitrobenzonitrile by using Hartree-Fock and density functional theory

NASA Astrophysics Data System (ADS)

Sert, Y.; Ucun, F.

2013-08-01

In the present work, the theoretical vibrational spectra of p-, m- and o-nitrobenzonitrile molecules have been analyzed. The harmonic vibrational frequencies and geometric parameters (bond lengths and bond angles) of these molecules have been calculated using ab initio Hartree-Fock and density functional theory methods with 6-311++G(d,p) basis set by Gaussian 03 W, for the first time. Assignments of the vibrational frequencies have been performed by potential energy distribution by using VEDA 4 program. The optimized geometric parameters and harmonic vibrational frequencies have been compared with the corresponding experimental data and seen to be in a good agreement with each other. Also, the highest occupied molecular orbital and lowest unoccupied molecular orbital energies have been obtained.

Rational F-theory GUTs without exotics

NASA Astrophysics Data System (ADS)

Krippendorf, Sven; Peña, Damián Kaloni Mayorga; Oehlmann, Paul-Konstantin; Ruehle, Fabian

2014-07-01

We construct F-theory GUT models without exotic matter, leading to the MSSM matter spectrum with potential singlet extensions. The interplay of engineering explicit geometric setups, absence of four-dimensional anomalies, and realistic phenomenology of the couplings places severe constraints on the allowed local models in a given geometry. In constructions based on the spectral cover we find no model satisfying all these requirements. We then provide a survey of models with additional U(1) symmetries arising from rational sections of the elliptic fibration in toric constructions and obtain phenomenologically appealing models based on SU(5) tops. Furthermore we perform a bottom-up exploration beyond the toric section constructions discussed in the literature so far and identify benchmark models passing all our criteria, which can serve as a guideline for future geometric engineering.

Applicability of modified effective-range theory to positron-atom and positron-molecule scattering

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

Idziaszek, Zbigniew; Karwasz, Grzegorz; Instytut Fizyki, Uniwersytet Mikolaja Kopernika, 87-100 Torun

2006-06-15

We analyze low-energy scattering of positrons on Ar atoms and N{sub 2} molecules using the modified effective-range theory (MERT) developed by O'Malley, et al. [J. Math. Phys. 2, 491 (1961)]. We use the formulation of MERT based on exact solutions of the Schroedinger equation with polarization potential rather than low-energy expansions of phase shifts into momentum series. We show that MERT describes the experimental data well, provided that effective-range expansion is performed both for s- and p-wave scattering, which dominate in the considered regime of positron energies (0.4-2 eV). We estimate the values of the s-wave scattering length and themore » effective range for e{sup +}-Ar and e{sup +}-N{sub 2} collisions.« less

Cartan symmetries and global dynamical systems analysis in a higher-order modified teleparallel theory

NASA Astrophysics Data System (ADS)

Karpathopoulos, L.; Basilakos, S.; Leon, G.; Paliathanasis, A.; Tsamparlis, M.

2018-07-01

In a higher-order modified teleparallel theory cosmological we present analytical cosmological solutions. In particular we determine forms of the unknown potential which drives the scalar field such that the field equations form a Liouville integrable system. For the determination of the conservation laws we apply the Cartan symmetries. Furthermore, inspired from our solutions, a toy model is studied and it is shown that it can describe the Supernova data, while at the same time introduces dark matter components in the Hubble function. When the extra matter source is a stiff fluid then we show how analytical solutions for Bianchi I universes can be constructed from our analysis. Finally, we perform a global dynamical analysis of the field equations by using variables different from that of the Hubble-normalization.

Linking Theory of Mind and Central Coherence Bias in Autism and in the General Population.

ERIC Educational Resources Information Center

Jarrold, Christopher; Butler, David W.; Cottington, Emily M.; Jimenez, Flora

2000-01-01

Three experiments investigated whether theory-of-mind deficits and weak central coherence might be functionally related. Found that theory-of-mind performance was inversely related to a measure of central coherence bias in the general population. Poor theory-of-mind performance was linked to weak central coherence among children with typical…

Cyclohexane isomerization. Unimolecular dynamics of the twist-boat intermediate.

PubMed

Kakhiani, Khatuna; Lourderaj, Upakarasamy; Hu, Wenfang; Birney, David; Hase, William L

2009-04-23

Direct dynamics simulations were performed at the HF/6-31G level of theory to investigate the intramolecular and unimolecuar dynamics of the twist-boat (TB) intermediate on the cyclohexane potential energy surface (PES). Additional calculations were performed at the MP2/aug-cc-pVDZ level of theory to further characterize the PES's stationary points. The trajectories were initiated at the C(1) and C(2) half-chair transition states (TSs) connecting a chair conformer with a TB intermediate, via an intrinsic reaction coordinate (IRC). Energy was added in accord with a microcanonical ensemble at the average energy for experiments at 263 K. Important nontransition state theory (TST), non-IRC, and non-RRKM dynamics were observed in the simulations. Trajectories initially directed toward the chair conformer had a high probability of recrossing the TS, with approximately 30% forming a TB intermediate instead of accessing the potential energy well for the conformer. The TB intermediate initially formed was not necessarily the one connected to the TS via the IRC. Of the trajectories initiated at the C(2) half-chair TS and initially directed toward the chair conformer, 35% formed a TB intermediate instead of the chair conformer. Also, of the trajectories forming a TB intermediate, only 16% formed the TB intermediate connected with the C(2) TS via the IRC. Up to eight consecutive TB --> TB isomerizations were followed, and non-RRKM behavior was observed in their dynamics. A TB can isomerize to two different TBs, one by a clockwise rotation of C-C-C-C dihedral angles and the other by a counterclockwise rotation. In contrast to RRKM theory, which predicts equivalent probabilities for these rotations, the trajectory dynamics show they are not equivalent and depend on whether the C(1) or C(2) half-chair TS is initially excited. Non-RRKM dynamics is also observed in the isomerization of the TB intermediates to the chair conformers. RRKM theory assumes equivalent probabilities for isomerizing to the two chair conformers. In contrast, for the first and following TB intermediate formed, there is a preference to isomerize to the chair conformer connected to the TS at which the trajectories were initiated. For the first TB intermediate formed, approximately 30% of the isomerization is to a chair conformer, but this fraction decreases for the later formed TB intermediates and becomes approximately 10% for the eighth consecutive TB intermediate formed.

Loudspeakers: Modeling and control

NASA Astrophysics Data System (ADS)

Al-Ali, Khalid Mohammad

This thesis documented a comprehensive study of loudspeaker modeling and control. A lumped-parameter model for a voice-coil loudspeaker in a vented enclosure was presented that derived from a consideration of physical principles. In addition, a low-frequency (20 Hz to 100 Hz), feedback control method designed to improve the nonlinear performance of the loudspeaker and a suitable performance measure for use in design and evaluation were proposed. Data from experiments performed on a variety of actual loudspeakers confirmed the practicality of the theory developed in this work. The lumped-parameter loudspeaker model, although simple, captured much of the nonlinear behavior of the loudspeaker. In addition, the model formulation allowed a straightforward application of modern control system methods and lent itself well to modern parametric identification techniques. The nonlinear performance of the loudspeaker system was evaluated using a suitable distortion measure that was proposed and compared with other distortion measures currently used in practice. Furthermore, the linearizing effect of feedback using a linear controller (both static and dynamic) was studied on a class of nonlinear systems. The results illustrated that the distortion reduction was potentially significant and a useful upper bound on the closed-loop distortion was found based on the sensitivity function of the system's linearization. A feedback scheme based on robust control theory was chosen for application to the loudspeaker system. Using the pressure output of the loudspeaker system for feedback, the technique offered significant advantages over those previously attempted. Illustrative examples were presented that proved the applicability of the theory developed in this dissertation to a variety of loudspeaker systems. The examples included a vented loudspeaker model and actual loudspeakers enclosed in both vented and sealed configurations. In each example, predictable and measurable distortion reduction at the output of the closed-loop system was recorded.

Experimental, DFT and molecular docking studies on 2-(2-mercaptophenylimino)-4-methyl-2H-chromen-7-ol

NASA Astrophysics Data System (ADS)

Singh, Ashok Kumar; Singh, Ravindra Kumar

2016-10-01

A new coumarin derivative 2-(2-mercaptophenylimino)-4-methyl-2H-chromen-7-ol (COMSB) was synthesized and characterized with the help of 1H,13C NMR, FT-IR, FT-Raman and mass spectrometry. All quantum calculations were performed at DFT level of theory using B3LYP functional and 6-31G (d,p) as basis set. The UV-Vis spectrum studied by TD-DFT theory, with a hybrid exchange-correlation functional using Coulomb-attenuating method (CAM-B3LYP) in solvent phase gives similar pattern of bands, at energies and is consistent with that of experimental findings. The detailed analysis of vibrational (IR and Raman) spectra and their assignments has been done by computing Potential Energy Distribution (PED) using Gar2ped. Intra-molecular interactions were analyzed by 'Atoms in molecule' (AIM) approach. Computed first static hyperpolarizability (β0 = 8.583 × 10-30 esu) indicates non-linear optical (NLO) response of the molecule. Molecular docking studies show that the title molecule may act as potential acetylcholine esterase (AChE) inhibitor.

Multiple shock reverberation compression of dense Ne up to the warm dense regime: Evaluating the theoretical models

NASA Astrophysics Data System (ADS)

Tang, J.; Gu, Y. J.; Chen, Q. F.; Li, Z. G.; Zheng, J.; Li, C. J.; Li, J. T.

2018-04-01

Multiple shock reverberation compression experiments are designed and performed to determine the equation of state of neon ranging from the initial dense gas up to the warm dense regime where the pressure is from about 40 MPa to 120 GPa and the temperature is from about 297 K up to above 20 000 K. The wide region experimental data are used to evaluate the available theoretical models. It is found that, for neon below 1.1 g/cm 3 , within the framework of density functional theory molecular dynamics, a van der Waals correction is meaningful. Under high pressure and temperature, results from the self-consistent fluid variational theory model are sensitive to the potential parameter and could give successful predictions in the whole experimental regime if a set of proper parameters is employed. The new observations on neon under megabar (1 Mbar =1011Pa ) pressure and eV temperature (1 eV ≈104K ) enrich the understanding on properties of warm dense matter and have potential applications in revealing the formation and evolution of gaseous giants or mega-Earths.

First-principles calculations of two cubic fluoropervskite compounds: RbFeF3 and RbNiF3

NASA Astrophysics Data System (ADS)

Mubarak, A. A.; Al-Omari, Saleh

2015-05-01

We present first-principles calculations of the structural, elastic, electronic, magnetic and optical properties for RbFeF3 and RbNiF3. The full-potential linear augmented plan wave (FP-LAPW) method within the density functional theory was utilized to perform the present calculations. We employed the generalized gradient approximation as exchange-correlation potential. It was found that the calculated analytical lattice parameters agree with previous studies. The analysis of elastic constants showed that the present compounds are elastically stable and anisotropic. Moreover, both compounds are classified as a ductile compound. The calculations of the band structure and density functional theory revealed that the RbFeF3 compound has a half-metallic behavior while the RbNiF3 compound has a semiconductor behavior with indirect (M-Γ) band gap. The ferromagnetic behavior was studied for both compounds. The optical properties were calculated for the radiation of up to 40 eV. A beneficial optics technology is predicted as revealed from the optical spectra.

Teaching About “Brain and Learning” in High School Biology Classes: Effects on Teachers' Knowledge and Students' Theory of Intelligence

PubMed Central

Dekker, Sanne; Jolles, Jelle

2015-01-01

This study evaluated a new teaching module about “Brain and Learning” using a controlled design. The module was implemented in high school biology classes and comprised three lessons: (1) brain processes underlying learning; (2) neuropsychological development during adolescence; and (3) lifestyle factors that influence learning performance. Participants were 32 biology teachers who were interested in “Brain and Learning” and 1241 students in grades 8–9. Teachers' knowledge and students' beliefs about learning potential were examined using online questionnaires. Results indicated that before intervention, biology teachers were significantly less familiar with how the brain functions and develops than with its structure and with basic neuroscientific concepts (46 vs. 75% correct answers). After intervention, teachers' knowledge of “Brain and Learning” had significantly increased (64%), and more students believed that intelligence is malleable (incremental theory). This emphasizes the potential value of a short teaching module, both for improving biology teachers' insights into “Brain and Learning,” and for changing students' beliefs about intelligence. PMID:26648900

Oscillations in the CMB from Axion Monodromy Inflation

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

Flauger, Raphael; /Texas U.; McAllister, Liam

2011-12-01

We study the CMB observables in axion monodromy inflation. These well-motivated scenarios for inflation in string theory have monomial potentials over super-Planckian field ranges, with superimposed sinusoidal modulations from instanton effects. Such periodic modulations of the potential can drive resonant enhancements of the correlation functions of cosmological perturbations, with characteristic modulations of the amplitude as a function of wavenumber. We give an analytical result for the scalar power spectrum in this class of models, and we determine the limits that present data places on the amplitude and frequency of modulations. Then, incorporating an improved understanding of the realization of axionmore » monodromy inflation in string theory, we perform a careful study of microphysical constraints in this scenario. We find that detectable modulations of the scalar power spectrum are commonplace in well-controlled examples, while resonant contributions to the bispectrum are undetectable in some classes of examples and detectable in others. We conclude that resonant contributions to the spectrum and bispectrum are a characteristic signature of axion monodromy inflation that, in favorable cases, could be detected in near-future experiments.« less

First-Principles Study of the Electronic Structure and Bonding Properties of X8C46 and X8B6C40 (X: Li, Na, Mg, Ca) Carbon Clathrates

NASA Astrophysics Data System (ADS)

KoleŻyński, Andrzej; Szczypka, Wojciech

2016-03-01

Results from theoretical analysis of the crystal structure, electronic structure, and bonding properties of C46 and B6C40 carbon clathrates doped with selected alkali and alkaline earth metals cations (Li, Na, Mg, Ca) are presented. The ab initio calculations were performed by means of the WIEN2k package (full potential linearized augmented plane wave method (FP-LAPW) within density functional theory (DFT)) with PBESol and modified Becke-Johnson exchange-correlation potentials used in geometry optimization and electronic structure calculations, respectively. The bonding properties were analyzed by applying Bader's quantum theory of atoms in molecules formalism to the topological properties of total electron density obtained from ab initio calculations. Analysis of the results obtained (i.a. equilibrium geometry, equation of state, cohesive energy, band structure, density of states—both total and projected on to particular atoms, and topological properties of bond critical points and net charges of topological atoms) is presented in detail.

Benchmarking fully analytic DFT force fields for vibrational spectroscopy: A study on halogenated compounds

NASA Astrophysics Data System (ADS)

Pietropolli Charmet, Andrea; Cornaton, Yann

2018-05-01

This work presents an investigation of the theoretical predictions yielded by anharmonic force fields having the cubic and quartic force constants are computed analytically by means of density functional theory (DFT) using the recursive scheme developed by M. Ringholm et al. (J. Comput. Chem. 35 (2014) 622). Different functionals (namely B3LYP, PBE, PBE0 and PW86x) and basis sets were used for calculating the anharmonic vibrational spectra of two halomethanes. The benchmark analysis carried out demonstrates the reliability and overall good performances offered by hybrid approaches, where the harmonic data obtained at the coupled cluster with single and double excitations level of theory augmented by a perturbational estimate of the effects of connected triple excitations, CCSD(T), are combined with the fully analytic higher order force constants yielded by DFT functionals. These methods lead to reliable and computationally affordable calculations of anharmonic vibrational spectra with an accuracy comparable to that yielded by hybrid force fields having the anharmonic force fields computed at second order Møller-Plesset perturbation theory (MP2) level of theory using numerical differentiation but without the corresponding potential issues related to computational costs and numerical errors.

Theory of mind performance in schizophrenia: diagnostic, symptom, and neuropsychological correlates.

PubMed

Greig, Tamasine C; Bryson, Gary J; Bell, Morris D

2004-01-01

The purpose of this study was to explore the relationship between Theory of Mind (ToM) performance and schizophrenia subtype, symptom, and neuropsychological variables. One hundred twenty-eight stable outpatients with schizophrenia or schizoaffective disorder were assessed during the intake phase of a vocational and cognitive rehabilitation study. Results indicate that ToM performance differed significantly by schizophrenia diagnosis, with people diagnosed with disorganized schizophrenia performing the most poorly. Theory of Mind performance was also significantly correlated with measures of thought disorder and verbal memory. Regression analysis revealed that thought disorder and verbal memory measures explained 30% of the variance in ToM scores. Findings suggest that there is theory of mind variance in the schizophrenia population and theory of mind is strongly related to thought disorder, verbal memory, and cognitive disorganization. Contrary to previous reports, ToM was not related to measures of paranoia.

Advanced Small Perturbation Potential Flow Theory for Unsteady Aerodynamic and Aeroelastic Analyses

NASA Technical Reports Server (NTRS)

Batina, John T.

2005-01-01

An advanced small perturbation (ASP) potential flow theory has been developed to improve upon the classical transonic small perturbation (TSP) theories that have been used in various computer codes. These computer codes are typically used for unsteady aerodynamic and aeroelastic analyses in the nonlinear transonic flight regime. The codes exploit the simplicity of stationary Cartesian meshes with the movement or deformation of the configuration under consideration incorporated into the solution algorithm through a planar surface boundary condition. The new ASP theory was developed methodically by first determining the essential elements required to produce full-potential-like solutions with a small perturbation approach on the requisite Cartesian grid. This level of accuracy required a higher-order streamwise mass flux and a mass conserving surface boundary condition. The ASP theory was further developed by determining the essential elements required to produce results that agreed well with Euler solutions. This level of accuracy required mass conserving entropy and vorticity effects, and second-order terms in the trailing wake boundary condition. Finally, an integral boundary layer procedure, applicable to both attached and shock-induced separated flows, was incorporated for viscous effects. The resulting ASP potential flow theory, including entropy, vorticity, and viscous effects, is shown to be mathematically more appropriate and computationally more accurate than the classical TSP theories. The formulaic details of the ASP theory are described fully and the improvements are demonstrated through careful comparisons with accepted alternative results and experimental data. The new theory has been used as the basis for a new computer code called ASP3D (Advanced Small Perturbation - 3D), which also is briefly described with representative results.

Performance management in healthcare: a critical analysis.

PubMed

Hewko, Sarah J; Cummings, Greta G

2016-01-01

Purpose - The purpose of this paper is to explore the underlying theoretical assumptions and implications of current micro-level performance management and evaluation (PME) practices, specifically within health-care organizations. PME encompasses all activities that are designed and conducted to align employee outputs with organizational goals. Design/methodology/approach - PME, in the context of healthcare, is analyzed through the lens of critical theory. Specifically, Habermas' theory of communicative action is used to highlight some of the questions that arise in looking critically at PME. To provide a richer definition of key theoretical concepts, the authors conducted a preliminary, exploratory hermeneutic semantic analysis of the key words "performance" and "management" and of the term "performance management". Findings - Analysis reveals that existing micro-level PME systems in health-care organizations have the potential to create a workforce that is compliant, dependent, technically oriented and passive, and to support health-care systems in which inequalities and power imbalances are perpetually reinforced. Practical implications - At a time when the health-care system is under increasing pressure to provide high-quality, affordable services with fewer resources, it may be wise to investigate new sector-specific ways of evaluating and managing performance. Originality/value - In this paper, written for health-care leaders and health human resource specialists, the theoretical assumptions and implications of current PME practices within health-care organizations are explored. It is hoped that readers will be inspired to support innovative PME practices within their organizations that encourage peak performance among health-care professionals.

Computability, Gödel's incompleteness theorem, and an inherent limit on the predictability of evolution

PubMed Central

Day, Troy

2012-01-01

The process of evolutionary diversification unfolds in a vast genotypic space of potential outcomes. During the past century, there have been remarkable advances in the development of theory for this diversification, and the theory's success rests, in part, on the scope of its applicability. A great deal of this theory focuses on a relatively small subset of the space of potential genotypes, chosen largely based on historical or contemporary patterns, and then predicts the evolutionary dynamics within this pre-defined set. To what extent can such an approach be pushed to a broader perspective that accounts for the potential open-endedness of evolutionary diversification? There have been a number of significant theoretical developments along these lines but the question of how far such theory can be pushed has not been addressed. Here a theorem is proven demonstrating that, because of the digital nature of inheritance, there are inherent limits on the kinds of questions that can be answered using such an approach. In particular, even in extremely simple evolutionary systems, a complete theory accounting for the potential open-endedness of evolution is unattainable unless evolution is progressive. The theorem is closely related to Gödel's incompleteness theorem, and to the halting problem from computability theory. PMID:21849390

Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs{sub 2} (A = K, Rb)

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

Azam, Sikander; Khan, Saleem Ayaz; Goumri-Said, Souraya, E-mail: Souraya.Goumri-Said@chemistry.gatech.edu

Highlights: • Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) using the full potential linear augmented plane wave method andmore » the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices.« less

Is Education a Fundamental Right? People's Lay Theories About Intellectual Potential Drive Their Positions on Education.

PubMed

Savani, Krishna; Rattan, Aneeta; Dweck, Carol S

2017-09-01

Does every child have a fundamental right to receive a high-quality education? We propose that people's beliefs about whether "nearly everyone" or "only some people" have high intellectual potential drive their positions on education. Three studies found that the more people believed that nearly everyone has high potential, the more they viewed education as a fundamental human right. Furthermore, people who viewed education as a fundamental right, in turn (a) were more likely to support the institution of free public education, (b) were more concerned upon learning that students in the country were not performing well academically compared with students in peer nations, and (c) were more likely to support redistributing educational funds more equitably across wealthier and poorer school districts. The studies show that people's beliefs about intellectual potential can influence their positions on education, which can affect the future quality of life for countless students.

A test of the embodied simulation theory of object perception: potentiation of responses to artifacts and animals.

PubMed

Matheson, Heath E; White, Nicole C; McMullen, Patricia A

2014-07-01

Theories of embodied object representation predict a tight association between sensorimotor processes and visual processing of manipulable objects. Previous research has shown that object handles can 'potentiate' a manual response (i.e., button press) to a congruent location. This potentiation effect is taken as evidence that objects automatically evoke sensorimotor simulations in response to the visual presentation of manipulable objects. In the present series of experiments, we investigated a critical prediction of the theory of embodied object representations that potentiation effects should be observed with manipulable artifacts but not non-manipulable animals. In four experiments we show that (a) potentiation effects are observed with animals and artifacts; (b) potentiation effects depend on the absolute size of the objects and (c) task context influences the presence/absence of potentiation effects. We conclude that potentiation effects do not provide evidence for embodied object representations, but are suggestive of a more general stimulus-response compatibility effect that may depend on the distribution of attention to different object features.

Effective potential kinetic theory for strongly coupled plasmas

NASA Astrophysics Data System (ADS)

Baalrud, Scott D.; Daligault, Jérôme

2016-11-01

The effective potential theory (EPT) is a recently proposed method for extending traditional plasma kinetic and transport theory into the strongly coupled regime. Validation from experiments and molecular dynamics simulations have shown it to be accurate up to the onset of liquid-like correlation parameters (corresponding to Γ ≃ 10-50 for the one-component plasma, depending on the process of interest). Here, this theory is briefly reviewed along with comparisons between the theory and molecular dynamics simulations for self-diffusivity and viscosity of the one-component plasma. A number of new results are also provided, including calculations of friction coefficients, energy exchange rates, stopping power, and mobility. The theory is also cast in the Landau and Fokker-Planck kinetic forms, which may prove useful for enabling efficient kinetic computations.

REMOTE, a Wireless Sensor Network Based System to Monitor Rowing Performance

PubMed Central

Llosa, Jordi; Vilajosana, Ignasi; Vilajosana, Xavier; Navarro, Nacho; Suriñach, Emma; Marquès, Joan Manuel

2009-01-01

In this paper, we take a hard look at the performance of REMOTE, a sensor network based application that provides a detailed picture of a boat movement, individual rower performance, or his/her performance compared with other crew members. The application analyzes data gathered with a WSN strategically deployed over a boat to obtain information on the boat and oar movements. Functionalities of REMOTE are compared to those of RowX [1] outdoor instrument, a commercial wired sensor instrument designed for similar purposes. This study demonstrates that with smart geometrical configuration of the sensors, rotation and translation of the oars and boat can be obtained. Three different tests are performed: laboratory calibration allows us to become familiar with the accelerometer readings and validate the theory, ergometer tests which help us to set the acquisition parameters, and on boat tests shows the application potential of this technologies in sports. PMID:22423204

When Task Conflict Becomes Personal

PubMed Central

Guenter, Hannes; van Emmerik, Hetty; Schreurs, Bert; Kuypers, Tom; van Iterson, Ad; Notelaers, Guy

2016-01-01

Although potentially beneficial, task conflict may threaten teams because it often leads to relationship conflict. Prior research has identified a set of interpersonal factors (e.g., team communication, team trust) that help attenuate this association. The purpose of this article is to provide an alternative perspective that focuses on the moderating role of performance-related factors (i.e., perceived team performance). Using social identity theory, we build a model that predicts how task conflict associates with growth in relationship conflict and how perceived team performance influences this association. We test a three-wave longitudinal model by means of random coefficient growth modeling, using data from 60 ongoing teams working in a health care organization. Results provide partial support for our hypotheses. Only when perceived team performance is low, do task conflicts relate with growth in relationship conflict. We conclude that perceived team performance seems to enable teams to uncouple task from relationship conflict. PMID:28190944

Expert performance in sport and the dynamics of talent development.

PubMed

Phillips, Elissa; Davids, Keith; Renshaw, Ian; Portus, Marc

2010-04-01

Research on expertise, talent identification and development has tended to be mono-disciplinary, typically adopting genocentric or environmentalist positions, with an overriding focus on operational issues. In this paper, the validity of dualist positions on sport expertise is evaluated. It is argued that, to advance understanding of expertise and talent development, a shift towards a multidisciplinary and integrative science focus is necessary, along with the development of a comprehensive multidisciplinary theoretical rationale. Here we elucidate dynamical systems theory as a multidisciplinary theoretical rationale for capturing how multiple interacting constraints can shape the development of expert performers. This approach suggests that talent development programmes should eschew the notion of common optimal performance models, emphasize the individual nature of pathways to expertise, and identify the range of interacting constraints that impinge on performance potential of individual athletes, rather than evaluating current performance on physical tests referenced to group norms.

Theory and Experiment of Binary Diffusion Coefficient of n-Alkanes in Dilute Gases.

PubMed

Liu, Changran; McGivern, W Sean; Manion, Jeffrey A; Wang, Hai

2016-10-10

Binary diffusion coefficients were measured for n-pentane, n-hexane, and n-octane in helium and of n-pentane in nitrogen over the temperature range of 300 to 600 K, using reversed-flow gas chromatography. A generalized, analytical theory is proposed for the binary diffusion coefficients of long-chain molecules in simple diluent gases, taking advantage of a recently developed gas-kinetic theory of the transport properties of nanoslender bodies in dilute free-molecular flows. The theory addresses the long-standing question about the applicability of the Chapman-Enskog theory in describing the transport properties of nonspherical molecular structures, or equivalently, the use of isotropic potentials of interaction for a roughly cylindrical molecular structure such as large normal alkanes. An approximate potential energy function is proposed for the intermolecular interaction of long-chain n-alkane with typical bath gases. Using this potential and the analytical theory for nanoslender bodies, we show that the diffusion coefficients of n-alkanes in typical bath gases can be treated by the resulting analytical model accurately, especially for compounds larger than n-butane.

6D fractional quantum Hall effect

NASA Astrophysics Data System (ADS)

Heckman, Jonathan J.; Tizzano, Luigi

2018-05-01

We present a 6D generalization of the fractional quantum Hall effect involving membranes coupled to a three-form potential in the presence of a large background four-form flux. The low energy physics is governed by a bulk 7D topological field theory of abelian three-form potentials with a single derivative Chern-Simons-like action coupled to a 6D anti-chiral theory of Euclidean effective strings. We derive the fractional conductivity, and explain how continued fractions which figure prominently in the classification of 6D superconformal field theories correspond to a hierarchy of excited states. Using methods from conformal field theory we also compute the analog of the Laughlin wavefunction. Compactification of the 7D theory provides a uniform perspective on various lower-dimensional gapped systems coupled to boundary degrees of freedom. We also show that a supersymmetric version of the 7D theory embeds in M-theory, and can be decoupled from gravity. Encouraged by this, we present a conjecture in which IIB string theory is an edge mode of a 10 + 2-dimensional bulk topological theory, thus placing all twelve dimensions of F-theory on a physical footing.

Winglets on low aspect ratio wings

NASA Technical Reports Server (NTRS)

Kuhlman, John M.; Liaw, Paul

1987-01-01

The drag reduction potentially available from the use of winglets at the tips of low aspect ratio (1.75-2.67) wings with pronounced (45-60 deg) leading edge sweep is assessed numerically for the case of a cruise design point at Mach of 0.8 and a lift coefficient of 0.3. Both wing-winglet and wing-alone design geometries are derived from a linear-theory, minimum induced drag design methodology. Relative performance is evaluated with a nonlinear extended small disturbance potential flow analysis code. Predicted lift coefficient/pressure drag coefficient increases at equal lift for the wing-winglet configurations over the wing-alone planform are of the order of 14.6-15.8, when boundary layer interaction is included.

Theoretical calculations of the pressure, forces, and moments at supersonic speeds due to various lateral motions acting on thin isolated vertical tails

NASA Technical Reports Server (NTRS)

Margolis, Kenneth; Bobbitt, Percy J

1956-01-01

Velocity potentials, pressure, distributions, and stability derivatives are derived by use of supersonic linearized theory for families of thin isolated vertical tails performing steady rolling, steady yawing, and constant-lateral-acceleration motions. Vertical-tail families (half-delta and rectangular plan forms) are considered for a broad Mach number range. Also considered are the vertical tail with arbitrary sweepback and taper ratio at Mach numbers for which both the leading edge and trailing edge of the tail are supersonic and the triangular vertical tail with a subsonic leading edge and a supersonic trailing edge. Expressions for potentials, pressures, and stability derivatives are tabulated.

Review of betavoltaic energy conversion

NASA Astrophysics Data System (ADS)

Olsen, Larry C.

1993-05-01

Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

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

Verma, U. P.; Nayak, V.

Quantum mechanical first principle calculations have been performed to study the electronic and structural properties of TiN and TiAs in zinc blende (ZB) and rock salt (RS) structures. The full-potential linearized augmented plane wave (FP-LAPW) method has been used within the framework of density functional theory (DFT). The exchange correlation functional has been solved employing generalized gradient approximation (GGA). Our predicted results for lattice constants are in good agreement with the earlier findings. The electronic band structures of TiX are metallic in both the phases.

Review of betavoltaic energy conversion

NASA Technical Reports Server (NTRS)

Olsen, Larry C.

1993-01-01

Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

Origin of photovoltage in perovskite solar cells probed by first-principles calculations

NASA Astrophysics Data System (ADS)

Echeverría-Arrondo, C.

2018-06-01

Hybrid halide perovskite solar cells hold great potential for photovoltaic applications, but suffer, however, from anomalous current density-voltage characteristics. With a view to further understanding the performance of these optoelectronic devices, we investigate a prototypical electron selective contact with density functional theory methods. Our computations on a TiO2/CH3NH3PbI3 heterojunction doped with Schottky defects at open circuit reveal a consistent picture of ions and interlayer excitons at the origin of photovoltage formation.

A Theory-Based Methodology for Analyzing Domain Suitability for Expert Systems Technology Applications

DTIC Science & Technology

1989-06-01

amount of data now available as a result of these experiments, we are still unable to explain the "why" or " how " of successful systems or to predict for...order to better understand the potential contribution of this research, it is important to first discuss how expert systems are developed and the...task performance through internal and external feedback. 9. Knowing how to act upon the feedback received. 10. Implementing the action based on the

Analysis of DoD Travel Management: An Application of Learning Curve Theory.

DTIC Science & Technology

1982-09-01

tI AFIT Control Number LSSR 72-82 AFIT RESEARCH ASSESSMENT The purpose of this questionnaire is to determine the potential for current and future...by the equivalent value that your agency received by virtue of AFIT performing the research . Can you estimate what this research would have cost if it...In-house). 4. Often it is not possible to attach equivalent dollar values to research , although the results of the research may, in fact, be

Equilibrium and Non-Equilibrium Condensation Phenomena in Tuneable 3D and 2D Bose Gases

DTIC Science & Technology

2016-04-01

condensed gas " which remains condensed above the expected critical temperature, and performed one of the first studies of the strongly-interacting "unitary...34 Bose gas . With the 2d harmonic trap we showed how the interaction-driven BKT phase is connected with purely statistical theory, and with the 3d...box trap we created the world’s first atomic BEC in a quasi-uniform potential. 15. SUBJECT TERMS EOARD, Bose gas , ultracold, condensation, equilibrium

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

Oegetbil, O.

After reviewing the existing results we give an extensive analysis of the critical points of the potentials of the gauged N=2 Yang-Mills/Einstein supergravity theories coupled to tensor multiplets and hypermultiplets. Our analysis includes all the possible gaugings of all N=2 Maxwell-Einstein supergravity theories whose scalar manifolds are symmetric spaces. In general, the scalar potential gets contributions from R-symmetry gauging, tensor couplings, and hypercouplings. We show that the coupling of a hypermultiplet into a theory whose potential has a nonzero value at its critical point, and gauging a compact subgroup of the hyperscalar isometry group will only rescale the value ofmore » the potential at the critical point by a positive factor, and therefore will not change the nature of an existing critical point. However this is not the case for noncompact SO(1,1) gaugings. An SO(1,1) gauging of the hyperisometry will generally lead to de Sitter vacua, which is analogous to the ground states found by simultaneously gauging SO(1,1) symmetry of the real scalar manifold with U(1){sub R} in earlier literature. SO(m,1) gaugings with m>1, which give contributions to the scalar potential only in the magical Jordan family theories, on the other hand, do not lead to de Sitter vacua. Anti-de Sitter vacua are generically obtained when the U(1){sub R} symmetry is gauged. We also show that it is possible to embed certain generic Jordan family theories into the magical Jordan family preserving the nature of the ground states. However the magical Jordan family theories have additional ground states which are not found in the generic Jordan family theories.« less

Performance of Children and Adolescents with Asperger Syndrome or High-Functioning Autism on Advanced Theory of Mind Tasks

ERIC Educational Resources Information Center

Kaland, Nils; Callesen, Kirsten; Moller-Nielsen, Annette; Mortensen, Erik Lykke; Smith, Lars

2008-01-01

Although a number of advanced theory of mind tasks have been developed, there is a dearth of information on whether performances on different tasks are associated. The present study examined the performance of 21 children and adolescents with diagnoses of Asperger syndrome (AS) and 20 typically developing controls on three advanced theory of mind…

COMPUTATIONAL ELECTROCHEMISTRY: AQUEOUS ONE-ELECTRON OXIDATION POTENTIALS FOR SUBSTITUTED ANILINES

EPA Science Inventory

Semiempirical molecular orbital theory and density functional theory are used to compute one-electron oxidation potentials for aniline and a set of 21 mono- and di-substituted anilines in aqueous solution. Linear relationships between theoretical predictions and experiment are co...

Proof of Concept in Disrupted Tactical Networking

DTIC Science & Technology

2017-09-01

because of the risk of detection. In this study , we design projectile-based mesh networking prototypes as one potential type of short-living network...to communicate because of the risk of detection. In this study , we design projectile-based mesh networking prototypes as one potential type of short...reader with a background in systems-theory. This study is designed using systems theory and uses systems theory as a lens through which to observe

Induced strain actuation of composite beams and rotor blades with embedded piezoceramic elements

NASA Astrophysics Data System (ADS)

Chen, Peter C.; Chopra, Inderjit

1996-02-01

The objective of this research is to develop a dynamically-scaled (Froude scale) helicopter rotor blade with embedded piezoceramic elements as sensors and actuators to control blade vibrations. A 6 ft diameter 2-bladed bearingless rotor model was built where each blade is embedded with banks of piezoelectric actuators at 0964-1726/5/1/005/img1 degree angles with respect to the beam axis on the top and bottom surfaces. A twist distribution along the blade span is achieved through in-phase excitation of the top and bottom actuators at equal potentials, while a bending distribution is achieved through out-of-phase excitation. In order to fix design variables and to optimize blade performance, a uniform strain beam theory is formulated to analytically predict the static bending and torsional response of composite rectangular beams with embedded piezoelectric actuators. Parameters such as bond thicknesses, actuator skew angle and actuator spacing are investigated by experiments and then validated by theory. The static bending and torsional response of the rotor blades is experimentally measured and correlated with theory. Dynamic torsional and bending responses are experimentally determined for frequencies from 2 - 120 Hz to assess the viability of a vibration reduction system based on piezo-actuation of blade twist. To assess the performance of the piezo-actuators in rotation, hover tests were conducted where accelerometers embedded in the blades were used to resolve the tip twist amplitudes. Although the magnitudes of blade twist attained in this experiment were small, it is expected that future models can be built with improved performance.

Temperature scaling method for Markov chains.

PubMed

Crosby, Lonnie D; Windus, Theresa L

2009-01-22

The use of ab initio potentials in Monte Carlo simulations aimed at investigating the nucleation kinetics of water clusters is complicated by the computational expense of the potential energy determinations. Furthermore, the common desire to investigate the temperature dependence of kinetic properties leads to an urgent need to reduce the expense of performing simulations at many different temperatures. A method is detailed that allows a Markov chain (obtained via Monte Carlo) at one temperature to be scaled to other temperatures of interest without the need to perform additional large simulations. This Markov chain temperature-scaling (TeS) can be generally applied to simulations geared for numerous applications. This paper shows the quality of results which can be obtained by TeS and the possible quantities which may be extracted from scaled Markov chains. Results are obtained for a 1-D analytical potential for which the exact solutions are known. Also, this method is applied to water clusters consisting of between 2 and 5 monomers, using Dynamical Nucleation Theory to determine the evaporation rate constant for monomer loss. Although ab initio potentials are not utilized in this paper, the benefit of this method is made apparent by using the Dang-Chang polarizable classical potential for water to obtain statistical properties at various temperatures.

The Influence of Financial Performance on Higher Education Academic Quality

ERIC Educational Resources Information Center

Montanaro, Marilee Kaye Fannon

2013-01-01

A variety of academic and financial performance metrics are used to assess higher education institution performance. However, there is no consensus on the best performance measures. Signaling theory and agency theory are used to frame the challenges of assessing post-secondary institution performance related to information asymmetry between the…

Spherical harmonics based descriptor for neural network potentials: Structure and dynamics of Au147 nanocluster.

PubMed

Jindal, Shweta; Chiriki, Siva; Bulusu, Satya S

2017-05-28

We propose a highly efficient method for fitting the potential energy surface of a nanocluster using a spherical harmonics based descriptor integrated with an artificial neural network. Our method achieves the accuracy of quantum mechanics and speed of empirical potentials. For large sized gold clusters (Au 147 ), the computational time for accurate calculation of energy and forces is about 1.7 s, which is faster by several orders of magnitude compared to density functional theory (DFT). This method is used to perform the global minimum optimizations and molecular dynamics simulations for Au 147 , and it is found that its global minimum is not an icosahedron. The isomer that can be regarded as the global minimum is found to be 4 eV lower in energy than the icosahedron and is confirmed from DFT. The geometry of the obtained global minimum contains 105 atoms on the surface and 42 atoms in the core. A brief study on the fluxionality in Au 147 is performed, and it is concluded that Au 147 has a dynamic surface, thus opening a new window for studying its reaction dynamics.

Spherical harmonics based descriptor for neural network potentials: Structure and dynamics of Au147 nanocluster

NASA Astrophysics Data System (ADS)

Jindal, Shweta; Chiriki, Siva; Bulusu, Satya S.

2017-05-01

We propose a highly efficient method for fitting the potential energy surface of a nanocluster using a spherical harmonics based descriptor integrated with an artificial neural network. Our method achieves the accuracy of quantum mechanics and speed of empirical potentials. For large sized gold clusters (Au147), the computational time for accurate calculation of energy and forces is about 1.7 s, which is faster by several orders of magnitude compared to density functional theory (DFT). This method is used to perform the global minimum optimizations and molecular dynamics simulations for Au147, and it is found that its global minimum is not an icosahedron. The isomer that can be regarded as the global minimum is found to be 4 eV lower in energy than the icosahedron and is confirmed from DFT. The geometry of the obtained global minimum contains 105 atoms on the surface and 42 atoms in the core. A brief study on the fluxionality in Au147 is performed, and it is concluded that Au147 has a dynamic surface, thus opening a new window for studying its reaction dynamics.

Design and Implementation of Scientific Software Components to Enable Multiscale Modeling: The Effective Fragment Potential (QM/EFP) Method

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

Gaenko, Alexander; Windus, Theresa L.; Sosonkina, Masha

2012-10-19

The design and development of scientific software components to provide an interface to the effective fragment potential (EFP) methods are reported. Multiscale modeling of physical and chemical phenomena demands the merging of software packages developed by research groups in significantly different fields. Componentization offers an efficient way to realize new high performance scientific methods by combining the best models available in different software packages without a need for package readaptation after the initial componentization is complete. The EFP method is an efficient electronic structure theory based model potential that is suitable for predictive modeling of intermolecular interactions in large molecularmore » systems, such as liquids, proteins, atmospheric aerosols, and nanoparticles, with an accuracy that is comparable to that of correlated ab initio methods. The developed components make the EFP functionality accessible for any scientific component-aware software package. The performance of the component is demonstrated on a protein interaction model, and its accuracy is compared with results obtained with coupled cluster methods.« less

Using managerial role motivation theory to predict career success.

PubMed

Holland, M G; Black, C H; Miner, J B

1987-01-01

Managerial role motivation theory has proved to be useful for understanding executive performance in a wide range of highly structured organizational environments. Consistent results of studies indicate that the theory may be useful for understanding managerial behavior and predicting performance in health care organizations.

A principled approach to the measurement of situation awareness in commercial aviation

NASA Technical Reports Server (NTRS)

Tenney, Yvette J.; Adams, Marilyn Jager; Pew, Richard W.; Huggins, A. W. F.; Rogers, William H.

1992-01-01

The issue of how to support situation awareness among crews of modern commercial aircraft is becoming especially important with the introduction of automation in the form of sophisticated flight management computers and expert systems designed to assist the crew. In this paper, cognitive theories are discussed that have relevance for the definition and measurement of situation awareness. These theories suggest that comprehension of the flow of events is an active process that is limited by the modularity of attention and memory constraints, but can be enhanced by expert knowledge and strategies. Three implications of this perspective for assessing and improving situation awareness are considered: (1) Scenario variations are proposed that tax awareness by placing demands on attention; (2) Experimental tasks and probes are described for assessing the cognitive processes that underlie situation awareness; and (3) The use of computer-based human performance models to augment the measures of situation awareness derived from performance data is explored. Finally, two potential example applications of the proposed assessment techniques are described, one concerning spatial awareness using wide field of view displays and the other emphasizing fault management in aircraft systems.

Theoretical prediction of the mechanistic pathways and kinetics of methylcyclohexane initiated by OH radicals

NASA Astrophysics Data System (ADS)

Begum, Saheen Shehnaz; Deka, Ramesh Chandra; Gour, Nand Kishor

2018-06-01

In this manuscript, we have systematically depicted the theoretical prediction of H-absorption from methylcyclohexane initiated by OH radical. For this we have performed dual-level of quantum chemical calculations on the gas-phase reactions between methylcyclohexane (MCH) and OH radical. Geometry optimisation and vibrational frequency calculations have been performed at BHandHLYP/6-311G(d,p) level of theory along with energetic calculations at coupled cluster CCSD(T) method using the same basis set. All the stationary points of titled reaction have been located on the potential energy surface. It has also been found that the H-abstraction takes place from -CH site of MCH, which is the minimum energy pathway than others. The rate constant was calculated using canonical transition state theory for MCH with OH radical and is found to be 3.27 × 10-12 cm3 molecule-1 s-1, which is in sound agreement with reported experimental data. The atmospheric lifetime of MCH and branching ratios of the reaction channels are also reported in the manuscript.

Randomness increases self-reported anxiety and neurophysiological correlates of performance monitoring

PubMed Central

Kay, Aaron C.; Inzlicht, Michael

2015-01-01

Several prominent theories spanning clinical, social and developmental psychology suggest that people are motivated to see the world as a sensible orderly place. These theories presuppose that randomness is aversive because it is associated with unpredictability. If this is the case, thinking that the world is random should lead to increased anxiety and heightened monitoring of one’s actions and their consequences. Here, we conduct experimental tests of both of these ideas. Participants read one of three passages: (i) comprehensible order, (ii) incomprehensible order and (iii) randomness. In Study 1, we examined the effects of these passages on self-reported anxiety. In Study 2, we examined the effects of the same manipulation on the error-related negativity (ERN), an event-related brain potential associated with performance monitoring. We found that messages about randomness increased self-reported anxiety and ERN amplitude relative to comprehensible order, whereas incomprehensible order had intermediate effects. These results lend support to the theoretically important idea that randomness is unsettling because it implies that the world is unpredictable. PMID:25062840

Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach

PubMed Central

Cheung, Mike W.-L.; Jak, Suzanne

2016-01-01

Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists—and probably the most crucial one—is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study. PMID:27242639

Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach.

PubMed

Cheung, Mike W-L; Jak, Suzanne

2016-01-01

Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists-and probably the most crucial one-is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study.

Locating structures and evolution pathways of reconstructed rutile TiO2(011) using genetic algorithm aided density functional theory calculations.

PubMed

Ding, Pan; Gong, Xue-Qing

2016-05-01

Titanium dioxide (TiO2) is an important metal oxide that has been used in many different applications. TiO2 has also been widely employed as a model system to study basic processes and reactions in surface chemistry and heterogeneous catalysis. In this work, we investigated the (011) surface of rutile TiO2 by focusing on its reconstruction. Density functional theory calculations aided by a genetic algorithm based optimization scheme were performed to extensively sample the potential energy surfaces of reconstructed rutile TiO2 structures that obey (2 × 1) periodicity. A lot of stable surface configurations were located, including the global-minimum configuration that was proposed previously. The wide variety of surface structures determined through the calculations performed in this work provide insight into the relationship between the atomic configuration of a surface and its stability. More importantly, several analytical schemes were proposed and tested to gauge the differences and similarities among various surface structures, aiding the construction of the complete pathway for the reconstruction process.

Improving Team Performance: Proceedings of the Rand Team Performance Workshop.

DTIC Science & Technology

1980-08-01

organization theory, small group processes, cognitive psychologi training and instruction , decision theory, artificial intelligence, and human engineering...theory, small group processes, cognitive psy- chology, training and instruction , heuristic modeling, decision theory, and human engineering. Within...interact with. The operators are taught about the equipment and how it works; the actual job is left to be learned aboard ship. The cognitive processes the

HARNESSING VALUES TO PROMOTE MOTIVATION IN EDUCATION.

PubMed

Harackiewicz, Judith M; Tibbetts, Yoi; Canning, Elizabeth; Hyde, Janet S

2014-01-01

We review the interventions that promote motivation in academic contexts, with a focus on two primary questions: How can we motivate students to take more STEM courses? Once in those STEM courses, how can we keep students motivated and promote their academic achievement? We have approached these two motivational questions from several perspectives, examining the theoretical issues with basic laboratory research, conducting longitudinal questionnaire studies in classrooms, and developing interventions implemented in different STEM contexts. Our research is grounded in three theories that we believe are complementary: expectancy-value theory (Eccles & Wigfield, 2002), interest theory (Hidi & Renninger, 2006), and self-affirmation theory (Steele, 1988). As social psychologists, we have focused on motivational theory and used experimental methods, with an emphasis on values - students' perceptions of the value of academic tasks and students' personal values that shape their experiences in academic contexts. We review the experimental field studies in high-school science and college psychology classes, in which utility-value interventions promoted interest and performance for high-school students in science classes and for undergraduate students in psychology courses. We also review a randomized intervention in which parents received information about the utility value of math and science for their teens in high school; this intervention led students to take nearly one semester more of science and mathematics, compared with the control group. Finally, we review an experimental study of values affirmation in a college biology course and found that the intervention improved performance and retention for first-generation college students, closing the social-class achievement gap by 50%. We conclude by discussing the mechanisms through which these interventions work. These interventions are exciting for their broad applicability in improving students' academic choices and performance, they are also exciting regarding their potential for contributions to basic science. The combination of laboratory experiments and field experiments is advancing our understanding of the motivational principles and almost certainly will continue to do so. At the same time, interventions may benefit from becoming increasingly targeted at specific motivational processes that are effective with particular groups or in particular contexts.

HARNESSING VALUES TO PROMOTE MOTIVATION IN EDUCATION

PubMed Central

Harackiewicz, Judith M.; Tibbetts, Yoi; Canning, Elizabeth; Hyde, Janet S.

2017-01-01

Purpose We review the interventions that promote motivation in academic contexts, with a focus on two primary questions: How can we motivate students to take more STEM courses? Once in those STEM courses, how can we keep students motivated and promote their academic achievement? Design/methodology/approach We have approached these two motivational questions from several perspectives, examining the theoretical issues with basic laboratory research, conducting longitudinal questionnaire studies in classrooms, and developing interventions implemented in different STEM contexts. Our research is grounded in three theories that we believe are complementary: expectancy-value theory (Eccles & Wigfield, 2002), interest theory (Hidi & Renninger, 2006), and self-affirmation theory (Steele, 1988). As social psychologists, we have focused on motivational theory and used experimental methods, with an emphasis on values – students’ perceptions of the value of academic tasks and students’ personal values that shape their experiences in academic contexts. Findings We review the experimental field studies in high-school science and college psychology classes, in which utility-value interventions promoted interest and performance for high-school students in science classes and for undergraduate students in psychology courses. We also review a randomized intervention in which parents received information about the utility value of math and science for their teens in high school; this intervention led students to take nearly one semester more of science and mathematics, compared with the control group. Finally, we review an experimental study of values affirmation in a college biology course and found that the intervention improved performance and retention for first-generation college students, closing the social-class achievement gap by 50%. We conclude by discussing the mechanisms through which these interventions work. Originality/value These interventions are exciting for their broad applicability in improving students’ academic choices and performance, they are also exciting regarding their potential for contributions to basic science. The combination of laboratory experiments and field experiments is advancing our understanding of the motivational principles and almost certainly will continue to do so. At the same time, interventions may benefit from becoming increasingly targeted at specific motivational processes that are effective with particular groups or in particular contexts. PMID:28890603

Buoyancy Driven Shear Flows of Bubble Suspensions

NASA Technical Reports Server (NTRS)

Koch, D. L.; Hill, R. J.; Chellppannair, T.; Zenit, R.; Zenit, R.; Spelt, P. D. M.

1999-01-01

In this work the gas volume fraction and the root-mean-squared fluid velocity are measured in buoyancy driven shear flows of bubble suspensions in a tall, inclined, rectangular channel. The experiments are performed under conditions where We << 1a nd Re >> 1, for which comparisons are made with kinetic theory and numerical simulations. Here Re = gamma(a(exp 2)/nu is the Reynolds number and We = rho(gamma(exp 2))a(exp 3)/sigma is the Weber number; gamma is the shear rate, a is the bubble radius, nu is the kinematic viscosity of the liquid, rho is the density of the liquid, and sigma is the surface tension of the gas/liquid interface. Kang et al. calculated the bubble phase pressure and velocity variance of sheared bubble suspensions under conditions where the bubbles are spherical and the liquid phase velocity field can be approximated using potential flow theory, i.e. We= 0 and Re >> 1. Such conditions can be achieved in an experiment using gas bubbles, with a radius of O(0.5mm), in water. The theory requires that there be no average relative motion of the gas and liquid phases, hence the motivation for an experimental program in microgravity. The necessity of performing preliminary, Earth based experiments, however, requires performing experiments where the gas phase rises in the liquid, which significantly complicates the comparison of experiments with theory. Rather than comparing experimental results with theory for a uniform, homogeneous shear flow, experiments can be compared directly with solutions of the averaged equations of motion for bubble suspensions. This requires accounting for the significant lift force acting on the gas phase when the bubbles rise parallel to the average velocity of the sheared suspension. Shear flows can be produced in which the bubble phase pressure gradient, arising from shear induced collisions amongst the bubbles, balances a body force (centrifugal or gravitational) on the gas phase. A steady, non-uniform gas volume fraction can be measured, from which the bubble phase pressure gradient can be obtained and compared to theory and numerical simulations. The presence of bounding walls further complicates the experiments, since the detailed interactions of the bubbles with bounding walls is not well understood, especially in the presence of gravity, where the momentum and energy exchange depends on the inclination of the wall.

Predicting the potentials, solubilities and stabilities of metal-acetylacetonates for non-aqueous redox flow batteries using density functional theory calculations

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

Kucharyson, J. F.; Cheng, L.; Tung, S. O.

New active materials are needed to improve the performance and reduce the cost of non-aqueous redox flow batteries (RFBs) for grid-scale energy storage applications. Efforts to develop better performing materials, which have largely been empirical, would benefit from a better understanding of relationships between structural, electronic and RFB-relevant functional properties. This paper focuses on metal-acetylacetonates, a class of metal coordination complexes that has shown promise for use in RFBs, and describes correlations between their experimentally measured standard potentials, solubilities, and stabilities (cycle lifes), and selected chemical, structural and electronic properties determined from Density Functional Theory (DFT) calculations. The training setmore » consisted of 16 complexes including 5 different metals and 11 different substituents on the acetylacetonate ligand. Standard potentials for those compounds were calculated and are in good agreement with experimentally measured results. A predictive equation based on the solvation energies and dipole moments, two easily computed properties, reasonably modeled the experimentally determined solubilities. Importantly, we were able to identify a descriptor for the stability of acetylacetonates. The experimentally determined stability, quantified as the cycle life to a given degree of degradation, correlated with the percentage of the highest occupied (HOMO) or lowest unoccupied molecular orbital (LUMO) on the metal of the complex. This percentage is influenced by the degree of ligand innocence (irreducibility), and complexes with the most innocent ligands yielded the most stable redox reactions. To this end, VO(acetylacetonate)(2) and Fe(acetylacetonate)(3), with nearly 80% of the HOMO and LUMO on the metal, possessed the most stable oxidation and reduction half-reactions, respectively. The structure-function relationships and correlations presented in this paper could be used to predict new, highly soluble and stable complexes for RFB applications.« less

Concentration transport calculations by an original C++ program with interediate fidelity physics through user-defined buildings with an emphasis on release scenarios in radiological facilities

NASA Astrophysics Data System (ADS)

Sayre, George Anthony

The purpose of this dissertation was to develop the C ++ program Emergency Dose to calculate transport of radionuclides through indoor spaces using intermediate fidelity physics that provides improved spatial heterogeneity over well-mixed models such as MELCORRTM and much lower computation times than CFD codes such as FLUENTRTM . Modified potential flow theory, which is an original formulation of potential flow theory with additions of turbulent jet and natural convection approximations, calculates spatially heterogeneous velocity fields that well-mixed models cannot predict. Other original contributions of MPFT are: (1) generation of high fidelity boundary conditions relative to well-mixed-CFD coupling methods (conflation), (2) broadening of potential flow applications to arbitrary indoor spaces previously restricted to specific applications such as exhaust hood studies, and (3) great reduction of computation time relative to CFD codes without total loss of heterogeneity. Additionally, the Lagrangian transport module, which is discussed in Sections 1.3 and 2.4, showcases an ensemble-based formulation thought to be original to interior studies. Velocity and concentration transport benchmarks against analogous formulations in COMSOLRTM produced favorable results with discrepancies resulting from the tetrahedral meshing used in COMSOLRTM outperforming the Cartesian method used by Emergency Dose. A performance comparison of the concentration transport modules against MELCORRTM showed that Emergency Dose held advantages over the well-mixed model especially in scenarios with many interior partitions and varied source positions. A performance comparison of velocity module against FLUENTRTM showed that viscous drag provided the largest error between Emergency Dose and CFD velocity calculations, but that Emergency Dose's turbulent jets well approximated the corresponding CFD jets. Overall, Emergency Dose was found to provide a viable intermediate solution method for concentration transport with relatively low computation times.

Molecular modeling, dynamics studies and density functional theory approaches to identify potential inhibitors of SIRT4 protein from Homo sapiens : a novel target for the treatment of type 2 diabetes.

PubMed

Choubey, Sanjay K; Prabhu, Dhamodharan; Nachiappan, Mutharasappan; Biswal, Jayshree; Jeyakanthan, Jeyaraman

2017-11-01

Type 2 diabetes is one of the biggest health challenges in the world and WHO projects it to be the 7th leading cause of death in 2030. It is a chronic condition affecting the way our body metabolizes sugar. Insulin resistance is high risk factor marked by expression of Lipoprotein Lipases and Peroxisome Proliferator-Activated Receptor that predisposes to type 2 diabetes. AMP-dependent protein kinase in AMPK signaling pathway is a central sensor of energy status. Deregulation of AMPK signaling leads to inflammation, oxidative stress, and deactivation of autophagy which are implicated in pathogenesis of insulin resistance. SIRT4 protein deactivates AMPK as well as directly inhibits insulin secretion. SIRT4 overexpression leads to dyslipidimeia, decreased fatty acid oxidation, and lipogenesis which are the characteristic features of insulin resistance promoting type 2 diabetes. This makes SIRT4 a novel therapeutic target to control type 2 diabetes. Virtual screening and molecular docking studies were performed to obtain potential ligands. To further optimize the geometry of protein-ligand complexes Quantum Polarized Ligand Docking was performed. Binding Free Energy was calculated for the top three ligand molecules. In view of exploring the stereoelectronic features of the ligand, density functional theory approach was implemented at B3LYP/6-31G* level. 30 ns MD simulation studies of the protein-ligand complexes were done. The present research work proposes ZINC12421989 as potential inhibitor of SIRT4 with docking score (-7.54 kcal/mol), docking energy (-51.34 kcal/mol), binding free energy (-70.21 kcal/mol), and comparatively low energy gap (-0.1786 eV) for HOMO and LUMO indicating reactivity of the lead molecule.

Rethinking Remediation: A Model to Support the Detailed Diagnosis of Clinicians' Performance Problems and the Development of Effective Remediation Plans.

PubMed

Prescott-Clements, Linda; Voller, Vicky; Bell, Mark; Nestors, Natasha; van der Vleuten, Cees P M

2017-01-01

The successful remediation of clinicians demonstrating poor performance in the workplace is essential to ensure the provision of safe patient care. Clinicians may develop performance problems for numerous reasons, including health, personal factors, the workplace environment, or outdated knowledge/skills. Performance problems are often complex involving multifactorial issues, encompassing knowledge, skills, and professional behaviors. It is important that (where possible and appropriate) clinicians are supported through effective remediation to return them to safe clinical practice. A review of the literature demonstrated that research into remediation is in its infancy, with little known about the effectiveness of remediation programs currently. Current strategies for the development of remediation programs are mostly "intuitive"; a few draw upon established theories to inform their approach. Similarly, although it has been established that identification of the nature/scope of performance problems through assessment is an essential first step within remediation, the need for a more widespread "diagnosis" of why the problems exist is emerging. These reasons for poor performance, particularly in the context of experienced practicing clinicians, are likely to have an impact on the potential success of remediation and should be considered within the "diagnosis." A new model for diagnosing the performance problems of the clinicians has been developed, using behavioral change theories to explore known barriers to successful remediation, such as insight, motivation, attitude, self-efficacy, and the working environment, in addition to addressing known deficits regarding knowledge and skills. This novel approach is described in this article. An initial feasibility study has demonstrated the acceptability and practical implementation of our model.

Induced strain actuation of composite beams and rotor blades with embedded piezoceramic elements

NASA Astrophysics Data System (ADS)

Chen, Peter C.; Chopra, Inderjit

1994-05-01

The objective of this research is to develop a dynamically scaled (Froude scale) helicopter rotor blade with embedded piezoceramic elements as sensors and actuators to control blade vibrations. A 6-ft-diameter two-bladed bearingless rotor model was built, where each blade is embedded with banks of piezoelectric actuators at +/- 45-degree angles with respect to the beam axis on the top and bottom surfaces. A twist distribution along the blade span is achieved through in-phase excitation of the top and bottom actuators at equal potentials, while a bending distribution is achieved through out-of-phase excitation. In order to fix design variables and to optimize blade performance, a uniform strain beam theory is formulated to analytically predict the static bending and torsional response of composite rectangular beams with embedded piezoelectric actuators. Parameters such as bond thicknesses, actuator skew angle, and actuator spacing are investigated by experiments and then validated by theory. The static bending and torsional response of the rotor blades is experimentally measured and correlated with theory. Dynamic torsional and bending responses are experimentally determined for frequencies from 2-120 HZ to assess the viability of a vibration reduction system based on piezoactuation of blade twist. Although the magnitudes of blade twist attained in this experiment were small, it is expected that future models can be built with improved performance.

Renormalization group method based on the ionization energy theory

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

Arulsamy, Andrew Das, E-mail: sadwerdna@gmail.com; School of Physics, University of Sydney, Sydney, New South Wales 2006

2011-03-15

Proofs are developed to explicitly show that the ionization energy theory is a renormalized theory, which mathematically exactly satisfies the renormalization group formalisms developed by Gell-Mann-Low, Shankar and Zinn-Justin. However, the cutoff parameter for the ionization energy theory relies on the energy-level spacing, instead of lattice point spacing in k-space. Subsequently, we apply the earlier proofs to prove that the mathematical structure of the ionization-energy dressed electron-electron screened Coulomb potential is exactly the same as the ionization-energy dressed electron-phonon interaction potential. The latter proof is proven by means of the second-order time-independent perturbation theory with the heavier effective mass condition,more » as required by the electron-electron screened Coulomb potential. The outcome of this proof is that we can derive the heat capacity and the Debye frequency as a function of ionization energy, which can be applied in strongly correlated matter and nanostructures.« less

Translating Theory into Practice: Implications of Japanese Management Theory for Student Personnel Administrators. NASPA Monograph Series Volume 3. First Edition.

ERIC Educational Resources Information Center

Deegan, William L.; And Others

Japanese management theory was studied to identify specific models for consideration by student personnel administrators. The report is organized into three sections: major components of Japanese management theory, potential implications for student personnel administration, and three models, based on components of Japanese management theory, for…

From square-well to Janus: Improved algorithm for integral equation theory and comparison with thermodynamic perturbation theory within the Kern-Frenkel model

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

Giacometti, Achille, E-mail: achille.giacometti@unive.it; Gögelein, Christoph, E-mail: christoph.goegelein@ds.mpg.de; Lado, Fred, E-mail: lado@ncsu.edu

2014-03-07

Building upon past work on the phase diagram of Janus fluids [F. Sciortino, A. Giacometti, and G. Pastore, Phys. Rev. Lett. 103, 237801 (2009)], we perform a detailed study of integral equation theory of the Kern-Frenkel potential with coverage that is tuned from the isotropic square-well fluid to the Janus limit. An improved algorithm for the reference hypernetted-chain (RHNC) equation for this problem is implemented that significantly extends the range of applicability of RHNC. Results for both structure and thermodynamics are presented and compared with numerical simulations. Unlike previous attempts, this algorithm is shown to be stable down to themore » Janus limit, thus paving the way for analyzing the frustration mechanism characteristic of the gas-liquid transition in the Janus system. The results are also compared with Barker-Henderson thermodynamic perturbation theory on the same model. We then discuss the pros and cons of both approaches within a unified treatment. On balance, RHNC integral equation theory, even with an isotropic hard-sphere reference system, is found to be a good compromise between accuracy of the results, computational effort, and uniform quality to tackle self-assembly processes in patchy colloids of complex nature. Further improvement in RHNC however clearly requires an anisotropic reference bridge function.« less

U(1) Wilson lattice gauge theories in digital quantum simulators

NASA Astrophysics Data System (ADS)

Muschik, Christine; Heyl, Markus; Martinez, Esteban; Monz, Thomas; Schindler, Philipp; Vogell, Berit; Dalmonte, Marcello; Hauke, Philipp; Blatt, Rainer; Zoller, Peter

2017-10-01

Lattice gauge theories describe fundamental phenomena in nature, but calculating their real-time dynamics on classical computers is notoriously difficult. In a recent publication (Martinez et al 2016 Nature 534 516), we proposed and experimentally demonstrated a digital quantum simulation of the paradigmatic Schwinger model, a U(1)-Wilson lattice gauge theory describing the interplay between fermionic matter and gauge bosons. Here, we provide a detailed theoretical analysis of the performance and the potential of this protocol. Our strategy is based on analytically integrating out the gauge bosons, which preserves exact gauge invariance but results in complicated long-range interactions between the matter fields. Trapped-ion platforms are naturally suited to implementing these interactions, allowing for an efficient quantum simulation of the model, with a number of gate operations that scales polynomially with system size. Employing numerical simulations, we illustrate that relevant phenomena can be observed in larger experimental systems, using as an example the production of particle-antiparticle pairs after a quantum quench. We investigate theoretically the robustness of the scheme towards generic error sources, and show that near-future experiments can reach regimes where finite-size effects are insignificant. We also discuss the challenges in quantum simulating the continuum limit of the theory. Using our scheme, fundamental phenomena of lattice gauge theories can be probed using a broad set of experimentally accessible observables, including the entanglement entropy and the vacuum persistence amplitude.

On the Applicability of DLVO Theory to the Prediction of Clay Colloids Stability.

PubMed

Missana; Adell

2000-10-01

The stability behavior of Na-montmorillonite colloids has been studied by combining the analysis of their surface charge properties and time-resolved dynamic light scattering experiments. The chemical surface model for several types of clays, including montmorillonite, has to take into account the double surface charge contribution due to their permanent structural charge and to their pH-dependent charge, which is developed at the edge sites, therefore, these stability studies were carried out as a function of both ionic strength and pH. DLVO theory is largely applied for the prediction of the stability of many colloidal systems, including the natural ones. This work shows that the stability behavior of Na-montmorillonite colloids cannot be satisfactorily reproduced by DLVO theory, using the surface parameters experimentally obtained. Particularly, this theory is unable to explain their pH-dependent stability behavior caused by the small charge at the edge sites. Based on these results, a literature review of DLVO stability prediction of clay colloids was performed. It confirmed that this theory is not capable of taking into account the double contribution to the total surface charge and, at the same time, pointed out the main uncertainties related to the appropriate use of the input parameters for the calculation as, for example, the Hamaker constant or the surface potential. Copyright 2000 Academic Press.

Second-order perturbation theory with a density matrix renormalization group self-consistent field reference function: theory and application to the study of chromium dimer.

PubMed

Kurashige, Yuki; Yanai, Takeshi

2011-09-07

We present a second-order perturbation theory based on a density matrix renormalization group self-consistent field (DMRG-SCF) reference function. The method reproduces the solution of the complete active space with second-order perturbation theory (CASPT2) when the DMRG reference function is represented by a sufficiently large number of renormalized many-body basis, thereby being named DMRG-CASPT2 method. The DMRG-SCF is able to describe non-dynamical correlation with large active space that is insurmountable to the conventional CASSCF method, while the second-order perturbation theory provides an efficient description of dynamical correlation effects. The capability of our implementation is demonstrated for an application to the potential energy curve of the chromium dimer, which is one of the most demanding multireference systems that require best electronic structure treatment for non-dynamical and dynamical correlation as well as large basis sets. The DMRG-CASPT2/cc-pwCV5Z calculations were performed with a large (3d double-shell) active space consisting of 28 orbitals. Our approach using large-size DMRG reference addressed the problems of why the dissociation energy is largely overestimated by CASPT2 with the small active space consisting of 12 orbitals (3d4s), and also is oversensitive to the choice of the zeroth-order Hamiltonian. © 2011 American Institute of Physics

INCORPORATING ENVIRONMENTAL AND ECONOMIC CONSIDERATIONS INTO PROCESS DESIGN: THE WASTE REDUCTION (WAR) ALGORITHM

EPA Science Inventory

A general theory known as the WAste Reduction (WASR) algorithm has been developed to describe the flow and the generation of potential environmental impact through a chemical process. This theory integrates environmental impact assessment into chemical process design Potential en...

THE WASTE REDUCTION (WAR) ALGORITHM: ENVIRONMENTAL IMPACTS, ENERGY CONSUMPTION, AND ENGINEERING ECONOMICS

EPA Science Inventory

A general theory known as the WAste Reduction (WAR) algorithm has been developed to describe the flow and the generation of potential environmental impact through a chemical process. This theory defines potential environmental impact indexes that characterize the generation and t...

Thermodynamic properties of charged three-dimensional black holes in the scalar-tensor gravity theory

NASA Astrophysics Data System (ADS)

Dehghani, M.

2018-02-01

Making use of the suitable transformation relations, the action of three-dimensional Einstein-Maxwell-dilaton gravity theory has been obtained from that of scalar-tensor modified gravity theory coupled to the Maxwell's electrodynamics as the matter field. Two new classes of the static three-dimensional charged dilatonic black holes, as the exact solutions to the coupled scalar, electromagnetic and gravitational field equations, have been obtained in the Einstein frame. Also, it has been found that the scalar potential can be written in the form of a generalized Liouville-type potential. The conserved black hole charge and masses as well as the black entropy, temperature, and electric potential have been calculated from the geometrical and thermodynamical approaches, separately. Through comparison of the results arisen from these two alternative approaches, the validity of the thermodynamical first law has been proved for both of the new black hole solutions in the Einstein frame. Making use of the canonical ensemble method, a black hole stability or phase transition analysis has been performed. Regarding the black hole heat capacity, with the black hole charge as a constant, the points of type-1 and type-2 phase transitions have been determined. Also, the ranges of the black hole horizon radius at which the Einstein black holes are thermally stable have been obtained for both of the new black hole solutions. Then making use of the inverse transformation relations, two new classes of the string black hole solutions have been obtained from their Einstein counterpart. The thermodynamics and thermal stability of the new string black hole solutions have been investigated. It has been found that thermodynamic properties of the new charged black holes are identical in the Einstein and Jordan frames.

Spectroscopic investigations (FT-IR, UV, 1H and 13C NMR) and DFT/TD-DFT calculations of potential analgesic drug 2-[2-(dimethylamino)ethyl]-6-methoxy-4-(pyridin-2-yl)-1(2H)-phthalazinone

NASA Astrophysics Data System (ADS)

Sroczyński, Dariusz; Malinowski, Zbigniew

2017-12-01

The theoretical molecular geometry and the IR, UV, 1H and 13C NMR spectroscopic properties of 2-[2-(dimethylamino)ethyl]-6-methoxy-4-(pyridin-2-yl)-1(2H)-phthalazinone with the previously demonstrated in vivo analgesic activity were characterized. The conformational analysis, performed using the molecular mechanics method with the General AMBER Force Field (GAFF) and the Density Functional Theory (DFT) approach with the B3LYP hybrid functional and the 6-31 + g(d) basis sets, allowed to determine the most stable rotamer. The theoretical molecular geometry of this conformer was then calculated at the B3LYP/6-311++g(d,p) level of theory, and its phthalazinone core was compared with the experimental geometry of 1(2H)-phthalazinone. The calculated vibrational frequencies and the potential energy distribution enabled to assign the theoretical vibrational modes to the experimental FT-IR bands. The UV spectrum calculated with the Time-Dependent Density Functional Theory (TD-DFT) method in methanol identified the main electronic transitions and their character. 1H and 13C NMR chemical shifts simulated by the Gauge-Independent Atomic Orbital (GIAO) method in chloroform confirmed the previous assignment of the experimental resonance signals. The stability of the molecule was considered taking into account the hyperconjugation and electron density delocalization effects evaluated by the Natural Bond Orbital (NBO) method. The calculated spatial distribution of molecular electrostatic potential made possible to estimate the regions with nucleophilic and electrophilic properties. The results of the potentiodynamic polarization measurements were also indicated the corrosion inhibition activity of the title compound on 100Cr6 bearing steel in 1 mol dm-3 HCl solution.

A mathematical model of a lithium/thionyl chloride primary cell

NASA Technical Reports Server (NTRS)

Evans, T. I.; Nguyen, T. V.; White, R. E.

1987-01-01

A 1-D mathematical model for the lithium/thionyl chloride primary cell was developed to investigate methods of improving its performance and safety. The model includes many of the components of a typical lithium/thionyl chloride cell such as the porous lithium chloride film which forms on the lithium anode surface. The governing equations are formulated from fundamental conservation laws using porous electrode theory and concentrated solution theory. The model is used to predict 1-D, time dependent profiles of concentration, porosity, current, and potential as well as cell temperature and voltage. When a certain discharge rate is required, the model can be used to determine the design criteria and operating variables which yield high cell capacities. Model predictions can be used to establish operational and design limits within which the thermal runaway problem, inherent in these cells, can be avoided.

Carbonic anhydrase inhibition of Schiff base derivative of imino-methyl-naphthalen-2-ol: Synthesis, structure elucidation, molecular docking, dynamic simulation and density functional theory calculations

NASA Astrophysics Data System (ADS)

Abbas, Saghir; Nasir, Hafiza Huma; Zaib, Sumera; Ali, Saqib; Mahmood, Tariq; Ayub, Khurshid; Tahir, Muhammad Nawaz; Iqbal, Jamshed

2018-03-01

In the present study, we have designed and synthesized a Schiff base derivative 3 and characterized by FT-IR, 1H and 13C NMR spectroscopy. Single crystal X-ray diffraction and NMR studies were also performed. The synthetic compound was screened for its inhibitory potential against carbonic anhydrase II. The experimental results were validated by molecular docking and dynamic simulations of compound 3 in the active pocket of enzyme. Important binding interactions with the key residues in the active site of the carbonic anhydrase enzyme were revealed. Moreover, supramolecular assembly of the title compound was analyzed by density functional theory (DFT) calculations. These studies rendered a more clear understanding for the demonstration of novel molecular mechanism involved in CA II inhibition by the synthesized compound.

Density functional theory calculations of 95Mo NMR parameters in solid-state compounds.

PubMed

Cuny, Jérôme; Furet, Eric; Gautier, Régis; Le Pollès, Laurent; Pickard, Chris J; d'Espinose de Lacaillerie, Jean-Baptiste

2009-12-21

The application of periodic density functional theory-based methods to the calculation of (95)Mo electric field gradient (EFG) and chemical shift (CS) tensors in solid-state molybdenum compounds is presented. Calculations of EFG tensors are performed using the projector augmented-wave (PAW) method. Comparison of the results with those obtained using the augmented plane wave + local orbitals (APW+lo) method and with available experimental values shows the reliability of the approach for (95)Mo EFG tensor calculation. CS tensors are calculated using the recently developed gauge-including projector augmented-wave (GIPAW) method. This work is the first application of the GIPAW method to a 4d transition-metal nucleus. The effects of ultra-soft pseudo-potential parameters, exchange-correlation functionals and structural parameters are precisely examined. Comparison with experimental results allows the validation of this computational formalism.

Electron-induced hydrogen loss in uracil in a water cluster environment

NASA Astrophysics Data System (ADS)

Smyth, M.; Kohanoff, J.; Fabrikant, I. I.

2014-05-01

Low-energy electron-impact hydrogen loss due to dissociative electron attachment (DEA) to the uracil and thymine molecules in a water cluster environment is investigated theoretically. Only the A'-resonance contribution, describing the near-threshold behavior of DEA, is incorporated. Calculations are based on the nonlocal complex potential theory and the multiple scattering theory, and are performed for a model target with basic properties of uracil and thymine, surrounded by five water molecules. The DEA cross section is strongly enhanced when the attaching molecule is embedded in a water cluster. This growth is due to two effects: the increase of the resonance lifetime and the negative shift in the resonance position due to interaction of the intermediate negative ion with the surrounding water molecules. A similar effect was earlier found in DEA to chlorofluorocarbons.

Avoiding threat in late adulthood: testing two life span theories of emotion.

PubMed

Orgeta, Vasiliki

2011-07-01

The purpose of the present research was to explore the time course of age-related attentional biases and the role of emotion regulation as a potential mediator of older adults' performance in an emotion dot probe task. In two studies, younger and older adults (N = 80) completed a visual probe detection task, which presented happy, angry, and sad facial expressions. Across both studies, age influenced attentional responses to angry faces. Results indicated a bias away from angry-related facial emotion information occurring relatively late in attention. Age effects were not attributable to decreasing information processing speed or visuoperceptual function. Current results demonstrated that an age-related attentional preference away from angry facial cues was mediated by efforts to suppress emotion. Findings are discussed in relation to current theories of sociocognitive aging.

Quantum Monte Carlo calculations of two neutrons in finite volume

DOE PAGES

Klos, P.; Lynn, J. E.; Tews, I.; ...

2016-11-18

Ab initio calculations provide direct access to the properties of pure neutron systems that are challenging to study experimentally. In addition to their importance for fundamental physics, their properties are required as input for effective field theories of the strong interaction. In this work, we perform auxiliary-field diffusion Monte Carlo calculations of the ground state and first excited state of two neutrons in a finite box, considering a simple contact potential as well as chiral effective field theory interactions. We compare the results against exact diagonalizations and present a detailed analysis of the finite-volume effects, whose understanding is crucial formore » determining observables from the calculated energies. Finally, using the Lüscher formula, we extract the low-energy S-wave scattering parameters from ground- and excited-state energies for different box sizes.« less

How to test gravitation theories by means of gravitational-wave measurements

NASA Technical Reports Server (NTRS)

Thorne, K. S.

1974-01-01

Gravitational-wave experiments are a potentially powerful tool for testing gravitation theories. Most theories in the literature predict rather different polarization properties for gravitational waves than are predicted by general relativity; and many theories predict anomalies in the propagation speeds of gravitational waves.

SU (2) lattice gauge theory simulations on Fermi GPUs

NASA Astrophysics Data System (ADS)

Cardoso, Nuno; Bicudo, Pedro

2011-05-01

In this work we explore the performance of CUDA in quenched lattice SU (2) simulations. CUDA, NVIDIA Compute Unified Device Architecture, is a hardware and software architecture developed by NVIDIA for computing on the GPU. We present an analysis and performance comparison between the GPU and CPU in single and double precision. Analyses with multiple GPUs and two different architectures (G200 and Fermi architectures) are also presented. In order to obtain a high performance, the code must be optimized for the GPU architecture, i.e., an implementation that exploits the memory hierarchy of the CUDA programming model. We produce codes for the Monte Carlo generation of SU (2) lattice gauge configurations, for the mean plaquette, for the Polyakov Loop at finite T and for the Wilson loop. We also present results for the potential using many configurations (50,000) without smearing and almost 2000 configurations with APE smearing. With two Fermi GPUs we have achieved an excellent performance of 200× the speed over one CPU, in single precision, around 110 Gflops/s. We also find that, using the Fermi architecture, double precision computations for the static quark-antiquark potential are not much slower (less than 2× slower) than single precision computations.

Exploring motivations to seek and undergo prosthodontic care: an empirical approach using the Theory of Planned Behavior construct

PubMed Central

Vieira, Antonio Hélio; Leles, Cláudio Rodrigues

2014-01-01

Motivations for seeking and undergoing prosthodontic care are poorly understood and are not often explored for clinical purposes when determining treatment need and understanding the factors related to the demand for health care and effective use. This article uses the Theory of Planned Behavior construct to identify factors related to the motivations of edentulous subjects to seek and undergo prosthodontic treatment. The conceptual framework of the Theory of Planned Behavior includes attitude toward behavior, an individual’s positive or negative evaluation of self-performance of the particular behavior; the subjective norm, an individual’s perception of social normative pressures or relevant others’ beliefs that he or she should or should not perform such behavior; and perceived behavioral control, or an individual’s perceived ease or difficulty in performing the particular behavior, determined by the total set of accessible control beliefs. These components mediate a subject’s intention and behavior toward an object and may also explain health-related behaviors, providing strong predictions across a range of health behaviors. This study suggests categories for each component of the Theory of Planned Behavior, based on clinical evidence and practical reasoning. Attitudes toward behavior include perceived consequences of no treatment, perceived potential benefits and risks of treatment, dental anxiety, previous experiences, and interpersonal abilities of the health care providers. The subjective norm includes the opinions of relevant others, advertisement, professionally defined normative need, perceived professional skills, and technical quality of care. Perceived behavioral control includes subject’s time, availability and opportunity, treatment costs, subject’s perceived need, and accessibility to dental care. This conceptual model represents a theoretical multidimensional model that may help clinicians better understand the patient’s treatment behaviors and provide additional information for clinical research on patient’s adherence to interventions in prosthodontics. PMID:25246777

Threshold collision-induced dissociation and theoretical study of protonated azobenzene

NASA Astrophysics Data System (ADS)

Rezaee, Mohammadreza; McNary, Christopher P.; Armentrout, P. B.

2017-10-01

Protonated azobenzene (AB), H+(C6H5N2C6H5), has been studied using threshold collision-induced dissociation in a guided ion beam tandem mass spectrometer. Product channels observed are C6H5N2+ + C6H6 and C6H5+ + N2 + C6H6. The experimental kinetic energy-dependent cross sections were analyzed using a statistical model that accounts for internal and kinetic energy distributions of the reactants, multiple collisions, and kinetic shifts. From this analysis, the activation energy barrier height of 2.02 ± 0.11 eV for benzene loss is measured. To identify the transition states (TSs) and intermediates (IMs) for these dissociations, relaxed potential energy surface (PES) scans were performed at the B3LYP/aug-cc-pVTZ level of theory. The PES indicates that there is a substantial activation energy along the dissociation reaction coordinate that is the rate-limiting step for benzene loss and at some levels of theory, for subsequent N2 loss as well. Relative energies of the reactant, TSs, IMs, and products were calculated at B3LYP, wB97XD, M06, PBEPBE, and MP2(full) levels of theory using both 6-311++G(2d,2p) and aug-cc-pVTZ basis sets. Comparison of the experimental results with theoretical values from various computational methods indicates how well these theoretical methods can predict thermochemical properties. In addition to these density functional theory and MP2 methods, several high accuracy multi-level calculations such as CBS-QB3, G3, G3MP2, G3B3MP2, G4, and G4MP2 were performed to determine the thermochemical properties of AB including the proton affinity and gas-phase basicity, and to compare the performance of different theoretical methods.

Comparing Habitat Suitability and Connectivity Modeling Methods for Conserving Pronghorn Migrations

PubMed Central

Poor, Erin E.; Loucks, Colby; Jakes, Andrew; Urban, Dean L.

2012-01-01

Terrestrial long-distance migrations are declining globally: in North America, nearly 75% have been lost. Yet there has been limited research comparing habitat suitability and connectivity models to identify migration corridors across increasingly fragmented landscapes. Here we use pronghorn (Antilocapra americana) migrations in prairie habitat to compare two types of models that identify habitat suitability: maximum entropy (Maxent) and expert-based (Analytic Hierarchy Process). We used distance to wells, distance to water, NDVI, land cover, distance to roads, terrain shape and fence presence to parameterize the models. We then used the output of these models as cost surfaces to compare two common connectivity models, least-cost modeling (LCM) and circuit theory. Using pronghorn movement data from spring and fall migrations, we identified potential migration corridors by combining each habitat suitability model with each connectivity model. The best performing model combination was Maxent with LCM corridors across both seasons. Maxent out-performed expert-based habitat suitability models for both spring and fall migrations. However, expert-based corridors can perform relatively well and are a cost-effective alternative if species location data are unavailable. Corridors created using LCM out-performed circuit theory, as measured by the number of pronghorn GPS locations present within the corridors. We suggest the use of a tiered approach using different corridor widths for prioritizing conservation and mitigation actions, such as fence removal or conservation easements. PMID:23166656

Comparing habitat suitability and connectivity modeling methods for conserving pronghorn migrations.

PubMed

Poor, Erin E; Loucks, Colby; Jakes, Andrew; Urban, Dean L

2012-01-01

Terrestrial long-distance migrations are declining globally: in North America, nearly 75% have been lost. Yet there has been limited research comparing habitat suitability and connectivity models to identify migration corridors across increasingly fragmented landscapes. Here we use pronghorn (Antilocapra americana) migrations in prairie habitat to compare two types of models that identify habitat suitability: maximum entropy (Maxent) and expert-based (Analytic Hierarchy Process). We used distance to wells, distance to water, NDVI, land cover, distance to roads, terrain shape and fence presence to parameterize the models. We then used the output of these models as cost surfaces to compare two common connectivity models, least-cost modeling (LCM) and circuit theory. Using pronghorn movement data from spring and fall migrations, we identified potential migration corridors by combining each habitat suitability model with each connectivity model. The best performing model combination was Maxent with LCM corridors across both seasons. Maxent out-performed expert-based habitat suitability models for both spring and fall migrations. However, expert-based corridors can perform relatively well and are a cost-effective alternative if species location data are unavailable. Corridors created using LCM out-performed circuit theory, as measured by the number of pronghorn GPS locations present within the corridors. We suggest the use of a tiered approach using different corridor widths for prioritizing conservation and mitigation actions, such as fence removal or conservation easements.

Vapour-liquid interfacial properties of square-well chains from density functional theory and Monte Carlo simulation.

PubMed

Martínez-Ruiz, Francisco José; Blas, Felipe J; Moreno-Ventas Bravo, A Ignacio; Míguez, José Manuel; MacDowell, Luis G

2017-05-17

The statistical associating fluid theory for attractive potentials of variable range (SAFT-VR) density functional theory (DFT) developed by [Gloor et al., J. Chem. Phys., 2004, 121, 12740-12759] is used to predict the interfacial behaviour of molecules modelled as fully-flexible square-well chains formed from tangentially-bonded monomers of diameter σ and potential range λ = 1.5σ. Four different model systems, comprising 4, 8, 12, and 16 monomers per molecule, are considered. In addition to that, we also compute a number of interfacial properties of molecular chains from direct simulation of the vapour-liquid interface. The simulations are performed in the canonical ensemble, and the vapour-liquid interfacial tension is evaluated using the wandering interface (WIM) method, a technique based on the thermodynamic definition of surface tension. Apart from surface tension, we also obtain density profiles, coexistence densities, vapour pressures, and critical temperature and density, paying particular attention to the effect of the chain length on these properties. According to our results, the main effect of increasing the chain length (at fixed temperature) is to sharpen the vapour-liquid interface and to increase the width of the biphasic coexistence region. As a result, the interfacial thickness decreases and the surface tension increases as the molecular chains get longer. The interfacial thickness and surface tension appear to exhibit an asymptotic limiting behaviour for long chains. A similar behaviour is also observed for the coexistence densities and critical properties. Agreement between theory and simulation results indicates that SAFT-VR DFT is only able to predict qualitatively the interfacial properties of the model. Our results are also compared with simulation data taken from the literature, including the vapour-liquid coexistence densities, vapour pressures, and surface tension.

Synthetic, XRD, non-covalent interactions and solvent dependent nonlinear optical studies of Sulfadiazine-Ortho-Vanillin Schiff base: (E)-4-((2-hydroxy-3-methoxy- benzylidene) amino)-N-(pyrimidin-2-yl)benzene-sulfonamide

NASA Astrophysics Data System (ADS)

Shahid, Muhammad; Salim, Muhammad; Khalid, Muhammad; Tahir, Muhammad Nawaz; Khan, Muhammad Usman; Braga, Ataualpa Albert Carmo

2018-06-01

In this study, Sulfadiazine-Ortho-Vanillin Schiff base namely (E)-4-((2-hydroxy-3-methoxybenzylidene)amino)sbnd N-(pyrimidin-2-yl)benzene-sulfonamide (BS) was synthesized. Chemical characterization and computational studies using different techniques like XRD, FT-IR, UV-Vis, NBO, FMO, and MEP have been employed. Density functional theory (DFT) calculations have been performed at M06-2X/6-311 + G(d,p) level of theory to obtain optimized geometry and vibrational wave numbers for (E)-4-((2-hydroxy-3-methoxybenzylidene)amino)sbnd N-(pyrimidin-2-yl)benzene-sulfonamide (BS). The DFT optimized geometry supports the experimental XRD parameters. Frontier molecular orbital (FMO) energies and molecular electrostatic potential (MEP) surfaces have been executed at M06-2X/6-311 + G(d,p) level of theory. NBO analysis has been carried out at M06-2X/6-311 + G(d,p) level which not only discovered the hyper conjugative interactions and stability in title molecule but also reconfirmed the existence of Nsbnd H⋯N hydrogen bonds between the dimer. The findings of small EHOMO-ELUMO gap shows less hardness and larger softness values which suggested the bioactiveness of the title molecule. Finally, the effect of solvent on nonlinear optical (NLO) properties has been executed using M06-2X level of theory and 6-311 + G (d,p) basis set. The solvent polarity enhanced the NLO response from 3.62 × 10-30 esu to 4.66 × 10-30 esu indicating the considerable NLO character hence in general may have potential applications in the development of non-linear optical materials.

Experiments and Reaction Models of Fundamental Combustion Properties

DTIC Science & Technology

2010-05-31

in liquid hydrocarbon flames Lennard - Jones 12-6 potential parameters were estimated for n-alkanes and 1-alkenes with carbon numbers ranging from 5...hydrocarbons, were studied both experimentally and numerically. The fuel mixtures were chosen in order to gain insight into potential kinetic couplings...initio electronic structure theory, transition state theory, and master equation modelling. The potential energy surface was examined with the coupled

Effective field theories for van der Waals interactions

NASA Astrophysics Data System (ADS)

Brambilla, Nora; Shtabovenko, Vladyslav; Tarrús Castellà, Jaume; Vairo, Antonio

2017-06-01

Van der Waals interactions between two neutral but polarizable systems at a separation R much larger than the typical size of the systems are at the core of a broad sweep of contemporary problems in settings ranging from atomic, molecular and condensed matter physics to strong interactions and gravity. In this paper, we reexamine the dispersive van der Waals interactions between two hydrogen atoms. The novelty of the analysis resides in the usage of nonrelativistic effective field theories of quantum electrodynamics. In this framework, the van der Waals potential acquires the meaning of a matching coefficient in an effective field theory, dubbed van der Waals effective field theory, suited to describe the low-energy dynamics of an atom pair. It may be computed systematically as a series in R times some typical atomic scale and in the fine-structure constant α . The van der Waals potential gets short-range contributions and radiative corrections, which we compute in dimensional regularization and renormalize here for the first time. Results are given in d space-time dimensions. One can distinguish among different regimes depending on the relative size between 1 /R and the typical atomic bound-state energy, which is of order m α2. Each regime is characterized by a specific hierarchy of scales and a corresponding tower of effective field theories. The short-distance regime is characterized by 1 /R ≫m α2 and the leading-order van der Waals potential is the London potential. We also compute next-to-next-to-next-to-leading-order corrections. In the long-distance regime we have 1 /R ≪m α2. In this regime, the van der Waals potential contains contact terms, which are parametrically larger than the Casimir-Polder potential that describes the potential at large distances. In the effective field theory, the Casimir-Polder potential counts as a next-to-next-to-next-to-leading-order effect. In the intermediate-distance regime, 1 /R ˜m α2, a significantly more complex potential is obtained. We compare this exact result with the two previous limiting cases. We conclude by commenting on the van der Waals interactions in the hadronic case.

Comparison of high-angle-of-attack slender-body theory and exact solutions for potential flow over an ellipsoid

NASA Technical Reports Server (NTRS)

Hemsch, Michael J.

1990-01-01

The accuracy of high-alpha slender-body theory (HASBT) for bodies with elliptical cross-sections is presently demonstrated by means of a comparison with exact solutions for incompressible potential flow over a wide range of ellipsoid geometries and angles of attack and sideslip. The addition of the appropriate trigonometric coefficients to the classical slender-body theory decomposition yields the formally correct HASBT, and results in accuracies previously considered unattainable.

Theories, models and frameworks used in capacity building interventions relevant to public health: a systematic review.

PubMed

Bergeron, Kim; Abdi, Samiya; DeCorby, Kara; Mensah, Gloria; Rempel, Benjamin; Manson, Heather

2017-11-28

There is limited research on capacity building interventions that include theoretical foundations. The purpose of this systematic review is to identify underlying theories, models and frameworks used to support capacity building interventions relevant to public health practice. The aim is to inform and improve capacity building practices and services offered by public health organizations. Four search strategies were used: 1) electronic database searching; 2) reference lists of included papers; 3) key informant consultation; and 4) grey literature searching. Inclusion and exclusion criteria are outlined with included papers focusing on capacity building, learning plans, professional development plans in combination with tools, resources, processes, procedures, steps, model, framework, guideline, described in a public health or healthcare setting, or non-government, government, or community organizations as they relate to healthcare, and explicitly or implicitly mention a theory, model and/or framework that grounds the type of capacity building approach developed. Quality assessment were performed on all included articles. Data analysis included a process for synthesizing, analyzing and presenting descriptive summaries, categorizing theoretical foundations according to which theory, model and/or framework was used and whether or not the theory, model or framework was implied or explicitly identified. Nineteen articles were included in this review. A total of 28 theories, models and frameworks were identified. Of this number, two theories (Diffusion of Innovations and Transformational Learning), two models (Ecological and Interactive Systems Framework for Dissemination and Implementation) and one framework (Bloom's Taxonomy of Learning) were identified as the most frequently cited. This review identifies specific theories, models and frameworks to support capacity building interventions relevant to public health organizations. It provides public health practitioners with a menu of potentially usable theories, models and frameworks to support capacity building efforts. The findings also support the need for the use of theories, models or frameworks to be intentional, explicitly identified, referenced and for it to be clearly outlined how they were applied to the capacity building intervention.

Exploration Opportunity Search of Near-earth Objects Based on Analytical Gradients

NASA Astrophysics Data System (ADS)

Ren, Yuan; Cui, Ping-Yuan; Luan, En-Jie

2008-07-01

The problem of search of opportunity for the exploration of near-earth minor objects is investigated. For rendezvous missions, the analytical gradients of the performance index with respect to the free parameters are derived using the variational calculus and the theory of state-transition matrix. After generating randomly some initial guesses in the search space, the performance index is optimized, guided by the analytical gradients, leading to the local minimum points representing the potential launch opportunities. This method not only keeps the global-search property of the traditional method, but also avoids the blindness in the latter, thereby increasing greatly the computing speed. Furthermore, with this method, the searching precision could be controlled effectively.

Reconsidering community-based health promotion: promise, performance, and potential.

PubMed

Merzel, Cheryl; D'Afflitti, Joanna

2003-04-01

Contemporary public health emphasizes a community-based approach to health promotion and disease prevention. The evidence from the past 20 years indicates, however, that many community-based programs have had only modest impact, with the notable exception of a number of HIV prevention programs. To better understand the reasons for these outcomes, we conducted a systematic literature review of 32 community-based prevention programs. Reasons for poor performance include methodological challenges to study design and evaluation, concurrent secular trends, smaller-than-expected effect sizes, limitations of the interventions, and limitations of theories used. The effectiveness of HIV programs appears to be related in part to extensive formative research and an emphasis on changing social norms.

Excitonic giant-dipole potentials in cuprous oxide

NASA Astrophysics Data System (ADS)

Kurz, Markus; Grünwald, Peter; Scheel, Stefan

2017-06-01

In this paper we predict the existence of a novel species of Wannier excitons when exposed to crossed electric and magnetic fields. In particular, we present a theory of giant-dipole excitons in Cu2O in crossed fields. Within our theoretical approach we perform a pseudoseparation of the center-of-mass motion for the field-dressed excitonic species, thereby obtaining an effective single-particle Hamiltonian for the relative motion. For arbitrary gauge fields we exactly separate the gauge-dependent kinetic-energy terms from the effective single-particle interaction potential. Depending on the applied field strengths and the specific field orientation, the potential for the relative motion of electron and hole exhibits an outer well at spatial separations up to several micrometers and depths up to 380 μ eV , leading to possible permanent excitonic electric dipole moments of around 3 ×106 D.

Theory and performance of plated thermocouples.

NASA Technical Reports Server (NTRS)

Pesko, R. N.; Ash, R. L.; Cupschalk, S. G.; Germain, E. F.

1972-01-01

A theory has been developed to describe the performance of thermocouples which have been formed by electroplating portions of one thermoelectric material with another. The electroplated leg of the thermocouple was modeled as a collection of infinitesimally small homogeneous thermocouples connected in series. Experiments were performed using several combinations of Constantan wire sizes and copper plating thicknesses. A transient method was used to develop the thermoelectric calibrations, and the theory was found to be in quite good agreement with the experiments. In addition, data gathered in a Soviet experiment were also found to be in close agreement with the theory.

Job Attitudes and Performance during Three Career Stages.

ERIC Educational Resources Information Center

Slocum, John W., Jr.; Cron, William L.

1985-01-01

Tested a theory suggesting three distinct career stages between 21 and 60, each with its own career issues, job attitudes, and behavior. Attitudinal and career measures from 675 salespersons supported the theory. Within each stage, different attitudes and behaviors predicted sales performance in accordance with the theory. (Author/NRB)

Evidence-based selection of theories for designing behaviour change interventions: using methods based on theoretical construct domains to understand clinicians' blood transfusion behaviour.

PubMed

Francis, Jill J; Stockton, Charlotte; Eccles, Martin P; Johnston, Marie; Cuthbertson, Brian H; Grimshaw, Jeremy M; Hyde, Chris; Tinmouth, Alan; Stanworth, Simon J

2009-11-01

Many theories of behaviour are potentially relevant to predictive and intervention studies but most studies investigate a narrow range of theories. Michie et al. (2005) agreed 12 'theoretical domains' from 33 theories that explain behaviour change. They developed a 'Theoretical Domains Interview' (TDI) for identifying relevant domains for specific clinical behaviours, but the framework has not been used for selecting theories for predictive studies. It was used here to investigate clinicians' transfusion behaviour in intensive care units (ICU). Evidence suggests that red blood cells transfusion could be reduced for some patients without reducing quality of care. (1) To identify the domains relevant to transfusion practice in ICUs and neonatal intensive care units (NICUs), using the TDI. (2) To use the identified domains to select appropriate theories for a study predicting transfusion behaviour. An adapted TDI about managing a patient with borderline haemoglobin by watching and waiting instead of transfusing red blood cells was used to conduct semi-structured, one-to-one interviews with 18 intensive care consultants and neonatologists across the UK. Relevant theoretical domains were: knowledge, beliefs about capabilities, beliefs about consequences, social influences, behavioural regulation. Further analysis at the construct level resulted in selection of seven theoretical approaches relevant to this context: Knowledge-Attitude-Behaviour Model, Theory of Planned Behaviour, Social Cognitive Theory, Operant Learning Theory, Control Theory, Normative Model of Work Team Effectiveness and Action Planning Approaches. This study illustrated, the use of the TDI to identify relevant domains in a complex area of inpatient care. This approach is potentially valuable for selecting theories relevant to predictive studies and resulted in greater breadth of potential explanations than would be achieved if a single theoretical model had been adopted.

Molecular simulation of disjoining-pressure isotherms for free liquid , Lennard-Jones thin films

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

Bhatt, Divesh; Newman, John; Radke, C.J.

2001-10-01

We present canonical-ensemble molecular-dynamics simulations of disjoining-pressure isotherms in Lennard-Jones free liquid films. Thermodynamics demands that the disjoining pressure is determined uniquely as a function of the chemical potential purely from the phase diagram of the fluid. Our results from molecular dynamics validate this argument. The inverse-sixth-power distance term in the Lennard-Jones intermolecular potential represents van der Waals dispersion forces. Hence, we compare our results with classical Hamaker theory that is based on dispersion forces but assumes a slab geometry for the density profile and completely neglects fluid structure and entropy. We find that the Hamaker constant obtained from ourmore » simulations is about an order of magnitude larger than that from classical theory. To investigate the origin of this discrepancy, we calculate the disjoining-pressure isotherm using a density-functional theory relaxing the inherent assumptions in the Hamaker theory and imparting to the fluid an approximate structure. For disjoining pressure as a function of chemical potential, the results of density-functional theory and molecular dynamics are very close. Even for disjoining-pressure isotherms, and the subsequently calculated Hamaker constant, results of the density-functional theory are closer to the molecular-dynamics simulations by about a factor of 4 compared to Hamaker theory. [References: 44]« less

Dental hygiene self-assessment: a key to quality care.

PubMed

DeVore, L; Fried, J L; Dailey, J; Qori, C G

2000-01-01

To help achieve the goal of delivering quality care to the public, this study applied the Theory of Reasoned Action to dental hygienists' self-assessment (appraisal of one's performance). This theory suggests that individuals are likely to exhibit a given behavior, i.e., self-assessment, when they view it positively and when they believe that important others think they should perform it. To date, no research has been conducted on the self-assessment (SA) behaviors of practicing dental hygienists. The following research questions were addressed: what/who are the (1) behavioral beliefs; (2) normative beliefs; (3) salient referents; (4) attitudes toward self-assessment; (5) intentions to perform self-assessment; (6) outcomes associated with self-assessment; and (7) motivations to comply with self-assessment in a representative sample of dental hygienists? This study consisted of two phases: Phase I, telephone interviews (N = 30) and Phase II, a mailed survey of 600 randomly selected subjects. Interview responses from Phase I determined questionnaire items. Survey data analysis included descriptive statistics and correlations of component mean scores. A total of 273 usable surveys were returned, achieving a 46% response rate. Respondents valued the potential benefits of SA with a statistical mean of 2.70 on a six point scale ranging from minus three to plus three. Attitude correlated strongly with intention to self-assess (R = .7455). Survey respondents are motivated by their own beliefs and perceived benefits of SA rather than by the values of others. The insights that were derived from this study will permit the development of strategies to enable dental hygiene educators and practitioners to incorporate self-assessment as part of quality assurance plans. Application of well-developed self-assessment strategies promises potential benefits for dental hygienists and the public they serve.

THE WASTE REDUCTION (WAR) ALGORITHM: ENVIRONMENTAL IMPACTS, ENERGY CONSUMPTION, AND ENGINEERING ECONOMICS

EPA Science Inventory

A general theory known as the Waste Reduction (WAR) Algorithm has been developed to describe the flow and the generation of potential environmental impact through a chemical process. The theory defines indexes that characterize the generation and the output of potential environm...

The Female Voice: Applications to Bowen's Family Systems Theory.

ERIC Educational Resources Information Center

Knudson-Martin, Carmen

1994-01-01

Responds to calls from feminist scholars to address potential biases against women in theories of family therapy. Summarizes findings from studies of female development and integrates findings into expanded model of Bowen's family systems theory. Includes case example comparing expanded model with traditional application of Bowen's theory.…

Integrating Implicit Leadership Theories, Leader-Member Exchange, Self-Efficacy, and Attachment Theory to Predict Job Performance.

PubMed

Khorakian, Alireza; Sharifirad, Mohammad Sadegh

2018-01-01

The impact of implicit leadership theories on performance and the mechanism linking them have received insufficient theoretical and research attention. Drawing on Bandura's social cognitive theory, the present study contributes theory through examining the assertion that higher congruence between followers' implicit leadership theory and the characteristics of supervisors enhance job performance through higher quality of leader-member exchange and self-efficacy. Moreover, in the proposed model, attachment insecurity was considered as the antecedent of the congruence and leader-member exchange in addition to the moderator of the relationship between them. Capitalizing upon Structural Equation Modeling (SEM), this study tested the model in a field study using a sample of employees in knowledge-oriented firms in Iran. The results suggest that the congruence between followers' implicit leadership theory and the characteristics of supervisors does not directly impact performance and leader-member exchange and self-efficacy are the full mediators. The results also showed that attachment insecurity is the predictor of neither the congruence nor the leader-member exchange. Additionally, attachment insecurity moderates the relationship between these two variables in a way that when attachment insecurity is high, the congruence has more positive impact on leader-member exchange.

A comparison between index of entropy and catastrophe theory methods for mapping groundwater potential in an arid region.

PubMed

Al-Abadi, Alaa M; Shahid, Shamsuddin

2015-09-01

In this study, index of entropy and catastrophe theory methods were used for demarcating groundwater potential in an arid region using weighted linear combination techniques in geographical information system (GIS) environment. A case study from Badra area in the eastern part of central of Iraq was analyzed and discussed. Six factors believed to have influence on groundwater occurrence namely elevation, slope, aquifer transmissivity and storativity, soil, and distance to fault were prepared as raster thematic layers to facility integration into GIS environment. The factors were chosen based on the availability of data and local conditions of the study area. Both techniques were used for computing weights and assigning ranks vital for applying weighted linear combination approach. The results of application of both modes indicated that the most influential groundwater occurrence factors were slope and elevation. The other factors have relatively smaller values of weights implying that these factors have a minor role in groundwater occurrence conditions. The groundwater potential index (GPI) values for both models were classified using natural break classification scheme into five categories: very low, low, moderate, high, and very high. For validation of generated GPI, the relative operating characteristic (ROC) curves were used. According to the obtained area under the curve, the catastrophe model with 78 % prediction accuracy was found to perform better than entropy model with 77 % prediction accuracy. The overall results indicated that both models have good capability for predicting groundwater potential zones.

Application of Dempster-Shafer theory, spatial analysis and remote sensing for groundwater potentiality and nitrate pollution analysis in the semi-arid region of Khuzestan, Iran.

PubMed

Rahmati, Omid; Melesse, Assefa M

2016-10-15

Effective management and sustainable development of groundwater resources of arid and semi-arid environments require monitoring of groundwater quality and quantity. The aim of this paper is to develop a reasonable methodological framework for producing the suitability map for drinking water through the geographic information system, remote sensing and field surveys of the Andimeshk-Dezful, Khozestan province, Iran as a semi-arid region. This study investigated the delineation of groundwater potential zone based on Dempster-Shafer (DS) theory of evidence and evaluate its applicability for groundwater potentiality mapping. The study also analyzed the spatial distribution of groundwater nitrate concentration; and produced the suitability map for drinking water. The study has been carried out with the following steps: i) creation of maps of groundwater conditioning factors; ii) assessment of groundwater occurrence characteristics; iii) creation of groundwater potentiality map (GPM) and model validation; iv) collection and chemical analysis of water samples; v) assessment of groundwater nitrate pollution; and vi) creation of groundwater potentiality and quality map. The performance of the DS was also evaluated using the receiver operating characteristic (ROC) curve method and pumping test data to ensure its generalization ability, which eventually, the GPM showed 87.76% accuracy. The detailed analysis of groundwater potentiality and quality revealed that the 'non acceptable' areas covers an area of about 1479km(2) (60%). The study will provide significant information for groundwater management and exploitation in areas where groundwater is a major source of water and its exploration is critical to support drinking water need. Copyright © 2016 Elsevier B.V. All rights reserved.

Theory of Mind and Its Neuropsychological and Quality of Life Correlates in the Early Stages of Amyotrophic Lateral Sclerosis.

PubMed

Trojsi, Francesca; Siciliano, Mattia; Russo, Antonio; Passaniti, Carla; Femiano, Cinzia; Ferrantino, Teresa; De Liguoro, Stefania; Lavorgna, Luigi; Monsurrò, Maria R; Tedeschi, Gioacchino; Santangelo, Gabriella

2016-01-01

This study aims to explore the potential impairment of Theory of Mind (ToM; i.e., the ability to represent cognitive and affective mental states to both self and others) and the clinical, neuropsychological and Quality of Life (QoL) correlates of these cognitive abnormalities in the early stages of amyotrophic lateral sclerosis (ALS), a multisystem neurodegenerative disease recently recognized as a part of the same clinical and pathological spectrum of frontotemporal lobar degeneration. Twenty-two consecutive, cognitively intact ALS patients, and 15 healthy controls, underwent assessment of executive, verbal comprehension, visuospatial, behavioral, and QoL measures, as well as of the ToM abilities by Emotion Attribution Task (EAT), Advanced Test of ToM (ATT), and Eyes Task (ET). ALS patients obtained significantly lower scores than controls on EAT and ET. No significant difference was found between the two groups on ATT. As regard to type of ALS onset, patients with bulbar onset performed worse than those with spinal onset on ET. Correlation analysis revealed that EAT and ET were positively correlated with education, memory prose, visuo-spatial performances, and "Mental Health" scores among QoL items. Our results suggest that not only "cognitive" but also "affective" subcomponents of ToM may be impaired in the early stages of ALS, with significant linkage to disease onset and dysfunctions of less executively demanding conditions, causing potential impact on patients' "Mental Health."

A systematic examination of preoperative surgery warm-up routines.

PubMed

Pike, T W; Pathak, S; Mushtaq, F; Wilkie, R M; Mon-Williams, M; Lodge, J P A

2017-05-01

Recent evidence indicates that a preoperative warm-up is a potentially useful tool in facilitating performance. But what factors drive such improvements and how should a warm-up be implemented? In order to address these issues, we adopted a two-pronged approach: (1) we conducted a systematic review of the literature to identify existing studies utilising preoperative simulation techniques; (2) we performed task analysis to identify the constituent parts of effective warm-ups. We identified five randomised control trials, four randomised cross-over trials and four case series. The majority of these studies reviewed surgical performance following preoperative simulation relative to performance without simulation. Four studies reported outcome measures in real patients and the remainder reported simulated outcome measures. All but one of the studies found that preoperative simulation improves operative outcomes-but this improvement was not found across all measured parameters. While the reviewed studies had a number of methodological issues, the global data indicate that preoperative simulation has substantial potential to improve surgical performance. Analysis of the task characteristics of successful interventions indicated that the majority of these studies employed warm-ups that focused on the visual motor elements of surgery. However, there was no theoretical or empirical basis to inform the design of the intervention in any of these studies. There is an urgent need for a more rigorous approach to the development of "warm-up" routines if the potential value of preoperative simulation is to be understood and realised. We propose that such interventions need to be grounded in theory and empirical evidence on human motor performance.

Generalised teleparallel quintom dark energy non-minimally coupled with the scalar torsion and a boundary term

NASA Astrophysics Data System (ADS)

Bahamonde, Sebastian; Marciu, Mihai; Rudra, Prabir

2018-04-01

Within this work, we propose a new generalised quintom dark energy model in the teleparallel alternative of general relativity theory, by considering a non-minimal coupling between the scalar fields of a quintom model with the scalar torsion component T and the boundary term B. In the teleparallel alternative of general relativity theory, the boundary term represents the divergence of the torsion vector, B=2∇μTμ, and is related to the Ricci scalar R and the torsion scalar T, by the fundamental relation: R=‑T+B. We have investigated the dynamical properties of the present quintom scenario in the teleparallel alternative of general relativity theory by performing a dynamical system analysis in the case of decomposable exponential potentials. The study analysed the structure of the phase space, revealing the fundamental dynamical effects of the scalar torsion and boundary couplings in the case of a more general quintom scenario. Additionally, a numerical approach to the model is presented to analyse the cosmological evolution of the system.

Non-statistical effects in bond fission reactions of 1,2-difluoroethane

NASA Astrophysics Data System (ADS)

Schranz, Harold W.; Raff, Lionel M.; Thompson, Donald L.

1991-08-01

A microcanonical, classical variational transition-state theory based on the use of the efficient microcanonical sampling (EMS) procedure is applied to simple bond fission in 1,2-difluoroethane. Comparison is made with results of trajectory calculations performed on the same global potential-energy surface. Agreement between the statistical theory and trajectory results for CC CF and CH bond fissions is poor with differences as large as a factor of 125. Most importantly, at the lower energy studied, 6.0 eV, the statistical calculations predict considerably slower rates than those computed from trajectories. We conclude from these results that the statistical assumptions inherent in the transition-state theory method are not valid for 1,2-difluoroethane in spite of the fact that the total intramolecular energy transfer rate out of CH and CC normal and local modes is large relative to the bond fission rates. The IVR rate is not globally rapid and the trajectories do not access all of the energetically available phase space uniformly on the timescale of the reactions.

Saddle-like deformation in a dielectric elastomer actuator embedded with liquid-phase gallium-indium electrodes

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

Wissman, J., E-mail: jwissman@andrew.cmu.edu; Finkenauer, L.; Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213

We introduce a dielectric elastomer actuator (DEA) composed of liquid-phase Gallium-Indium (GaIn) alloy electrodes embedded between layers of poly(dimethylsiloxane) (PDMS) and examine its mechanics using a specialized elastic shell theory. Residual stresses in the dielectric and sealing layers of PDMS cause the DEA to deform into a saddle-like geometry (Gaussian curvature K<0). Applying voltage Φ to the liquid metal electrodes induces electrostatic pressure (Maxwell stress) on the dielectric and relieves some of the residual stress. This reduces the longitudinal bending curvature and corresponding angle of deflection ϑ. Treating the elastomer as an incompressible, isotropic, NeoHookean solid, we develop a theorymore » based on the principle of minimum potential energy to predict the principal curvatures as a function of Φ. Based on this theory, we predict a dependency of ϑ on Φ that is in strong agreement with experimental measurements performed on a GaIn-PDMS composite. By accurately modeling electromechanical coupling in a soft-matter DEA, this theory can inform improvements in design and fabrication.« less

Development and application of an analysis of axisymmetric body effects on helicopter rotor aerodynamics using modified slender body theory

NASA Technical Reports Server (NTRS)

Yamauchi, G.; Johnson, W.

1984-01-01

A computationally efficient body analysis designed to couple with a comprehensive helicopter analysis is developed in order to calculate the body-induced aerodynamic effects on rotor performance and loads. A modified slender body theory is used as the body model. With the objective of demonstrating the accuracy, efficiency, and application of the method, the analysis at this stage is restricted to axisymmetric bodies at zero angle of attack. By comparing with results from an exact analysis for simple body shapes, it is found that the modified slender body theory provides an accurate potential flow solution for moderately thick bodies, with only a 10%-20% increase in computational effort over that of an isolated rotor analysis. The computational ease of this method provides a means for routine assessment of body-induced effects on a rotor. Results are given for several configurations that typify those being used in the Ames 40- by 80-Foot Wind Tunnel and in the rotor-body aerodynamic interference tests being conducted at Ames. A rotor-hybrid airship configuration is also analyzed.

Site-occupation embedding theory using Bethe ansatz local density approximations

NASA Astrophysics Data System (ADS)

Senjean, Bruno; Nakatani, Naoki; Tsuchiizu, Masahisa; Fromager, Emmanuel

2018-06-01

Site-occupation embedding theory (SOET) is an alternative formulation of density functional theory (DFT) for model Hamiltonians where the fully interacting Hubbard problem is mapped, in principle exactly, onto an impurity-interacting (rather than a noninteracting) one. It provides a rigorous framework for combining wave-function (or Green function)-based methods with DFT. In this work, exact expressions for the per-site energy and double occupation of the uniform Hubbard model are derived in the context of SOET. As readily seen from these derivations, the so-called bath contribution to the per-site correlation energy is, in addition to the latter, the key density functional quantity to model in SOET. Various approximations based on Bethe ansatz and perturbative solutions to the Hubbard and single-impurity Anderson models are constructed and tested on a one-dimensional ring. The self-consistent calculation of the embedded impurity wave function has been performed with the density-matrix renormalization group method. It has been shown that promising results are obtained in specific regimes of correlation and density. Possible further developments have been proposed in order to provide reliable embedding functionals and potentials.

Performing Leadership: Use of Performative Inquiry in Teaching Organizational Theories

ERIC Educational Resources Information Center

Nilson, Michelle; Fels, Lynn; Gopaul, Bryan

2016-01-01

This research explores the various ways in which performative inquiry was implemented in a graduate organizational theories course within an educational leadership cohort at a medium-sized urban Canadian research university. Drawing on Fink's framework for significant learning experiences, the researchers used performative inquiry to enact the…

Charging of nonspherical macroparticles in a plasma

NASA Astrophysics Data System (ADS)

Holgate, J. T.; Coppins, M.

2016-03-01

The current theories of macroparticle charging in a plasma are limited to spheres, and are unsuitable for the multitude of nonspherical objects existing in astrophysical, atmospheric, laboratory, and fusion plasmas. This paper extends the most widely used spherical charging theory, orbit motion limited theory, to spheroids and, as such, provides a comprehensive study of the charging of nonspherical objects in a plasma. The spherical charging theory is shown to be a reasonable approximation for a considerable range of spheroids. However, the electric potential of highly elongated spheroids can be almost twice the spherical value. Furthermore, the total charge on the spheroids increases by a significantly larger factor than their potential.

Neuropharmacology of performance monitoring.

PubMed

Jocham, Gerhard; Ullsperger, Markus

2009-01-01

Adaptive, goal-directed behavior requires that organisms evaluate their actions in terms of their outcomes. Neuroimaging studies show that unfavorable outcomes or situations with high level of conflict engage the posterior medial frontal cortex (pMFC). Recording of event-related potentials revealed that these situations are accompanied by a negative deflection, the so-called error-related negativity (ERN), which appears after an erroneous response or after negative feedback. Both activation of the pMFC and the ERN are thought to represent a signal that indicates the need for behavioral adjustment, and to recruit other brain regions that implement these adjustments. While many fMRI and EEG studies have shed light on the anatomical structures and the cognitive processes involved in performance monitoring, only very recently have researchers begun to investigate the underlying neurochemical mechanisms. Drawing on the putative involvement of dopamine (DA) neurons in coding a reward prediction error, an influential theory has ascribed a pivotal role to DA in performance monitoring. However, although important, DA is certainly not the only neuromodulator involved. Recent studies point to a role for serotonin, norepinephrine and GABA, but also for adenosine in performance monitoring. Here, we review the evidence for neurotransmitter effects on this function in humans. In this light, we critically discuss currently debated models of performance monitoring and potential alternatives.

Vibration training: could it enhance the strength, power, or speed of athletes?

PubMed

Wilcock, Ian M; Whatman, Chris; Harris, Nigel; Keogh, Justin W L

2009-03-01

The aim of this literature review was to determine whether vibration training could produce chronic improvements in the physical performance of trained athletes. Although the main objective was to analyze any performance benefits, a brief review of possible mechanisms linked to performance enhancement is also included. Vibration causes an increase in the g-forces acting on the muscles, increasing the loading parameters of any exercise. Increased loading should aid muscle hypertrophy, and some authors have suggested that vibration may enhance neuromuscular potentiation. Considering the 6 studies on trained athletes, there does seem to be some evidence to suggest that vibration may provide a small benefit to maximal strength (1-repetition maximum) and power (countermovement jumps) of trained athletes. Speed does not seem to be enhanced by vibration training. There is a lack of evidence to support the theory that long-term vibration training increases neuromuscular potentiation in trained athletes. What mechanism(s) could be responsible for possible strength and power enhancement is unclear. Because whole-body vibration does not seem to be detrimental to performance when used in a controlled manner, it could provide an additional training stimulus for athletes. However, further research is required to determine optimum vibration training protocols and to clarify whether vibration training produces performance benefits greater than those of traditional training methods.

Extending the Diffuse Layer Model of Surface Acidity Constant Behavior: IV. Diffuse Layer Charge/Potential Relationships

EPA Science Inventory

Most current electrostatic surface complexation models describing ionic binding at the particle/water interface rely on the use of Poisson - Boltzmann (PB) theory for relating diffuse layer charge densities to diffuse layer electrostatic potentials. PB theory is known to contain ...

Are the Performance Based Logistics Prophets Using Science or Alchemy to Create Life-Cycle Affordability? Using Theory to Predict the Efficacy of Performance Based Logistics

DTIC Science & Technology

2013-10-01

Based Logistics Prophets Using Science or Alchemy to Create Life-Cycle Affordability? Using Theory to Predict the Efficacy of Performance Based...Using Science or Alchemy to Create Life-Cycle Affordability? Using Theory to Predict the Efficacy of Performance Based Logistics 5a. CONTRACT NUMBER 5b...Are the PBL Prophets Using Science or Alchemy to Create Life Cycle Affordability? 328Defense ARJ, October 2013, Vol. 20 No. 3 : 325–348 Defense

Intrinsic motivation, performance, and the mediating role of mastery goal orientation: a test of self-determination theory.

PubMed

Cerasoli, Christopher P; Ford, Michael T

2014-01-01

Although intrinsic motivation has been linked repeatedly to performance and outcomes, the causal relationship between the two has remained unclear. To explain the link, this study considered the focusing influence of mastery goals. Using a three-wave panel study and hypotheses drawn from self-determination theory and achievement goal theory, the current study sought to clarify the relationships between intrinsic motivation, mastery goal orientation, and performance. Specifically, the current study hypothesized and found that mastery goals mediated (explained) the relationship between intrinsic motivation and performance.

Freezing of simple systems using density functional theory

NASA Astrophysics Data System (ADS)

de Kuijper, A.; Vos, W. L.; Barrat, J.-L.; Hansen, J.-P.; Schouten, J. A.

1990-10-01

Density functional theory (DFT) has been applied to the study of the fluid-solid transition in systems with realistic potentials (soft cores and attractive forces): the purely repulsive WCA Lennard-Jones reference potential (LJT), the full Lennard-Jones potential (LJ) and the exponential-6 potential appropriate for helium and hydrogen. Three different DFT formalisms were used: the formulation of Haymet and Oxtoby (HO) and the new theories of Denton and Ashcroft (MWDA) and of Baus (MELA). The results for the melting pressure are compared with recent simulation and experimental data. The results of the HO version are always too high, the deviation increasing when going from the repulsive Lennard-Jones to the exponential-6 potential of H2. The MWDA gives too low results for the repulsive Lennard-Jones potential. At low temperatures, it fails for the full LJ potential while at high temperatures it is in good agreement. Including the attraction as a mean-field correction gives good results also for low temperatures. The MWDA results are too high for the exponential-6 potentials. The MELA fails completely for the LJT potential and the hydrogen exponential-6 potential, since it does not give a stable solid phase.

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

Hill, Christopher T.

We review and expand upon recent work demonstrating that Weyl invariant theories can be broken "inertially," which does not depend upon a potential. This can be understood in a general way by the "current algebra" of these theories, independently of specific Lagrangians. Maintaining the exact Weyl invariance in a renormalized quantum theory can be accomplished by renormalization conditions that refer back to the VEV's of fields in the action. We illustrate the computation of a Weyl invariant Coleman-Weinberg potential that breaks a U(1) symmetry together,with scale invariance.

Exposure to Psychological Aggression at Work and Job Performance: The Mediating Role of Job Attitudes and Personal Health

PubMed Central

Schat, Aaron; Frone, Michael R.

2011-01-01

Despite the growing literature on workplace aggression and the importance of employee performance at work, few studies have examined the relation between workplace aggression and job performance. The purpose of this study was to investigate the relations between psychological aggression at work and two forms of job performance (task performance and contextual performance) and potential mediators of these relations. Based on Conservation of Resources theory and prior research, a model was developed and tested in which overall job attitudes (i.e., job satisfaction and organizational commitment) and overall personal health (i.e., physical and psychological health) fully mediate the relations between exposure to psychological aggression at work and both task performance and contextual performance. Data were obtained from a national probability sample of US workers (N = 2376) and the model was tested using structural equation modelling. The results supported the hypothesized model, demonstrating that exposure to psychological aggression at work negatively predicted both task performance and contextual performance, and that these relations were explained by decrements in job attitudes and health associated with exposure to psychological aggression at work. PMID:21643471

Exposure to Psychological Aggression at Work and Job Performance: The Mediating Role of Job Attitudes and Personal Health.

PubMed

Schat, Aaron; Frone, Michael R

2011-01-01

Despite the growing literature on workplace aggression and the importance of employee performance at work, few studies have examined the relation between workplace aggression and job performance. The purpose of this study was to investigate the relations between psychological aggression at work and two forms of job performance (task performance and contextual performance) and potential mediators of these relations. Based on Conservation of Resources theory and prior research, a model was developed and tested in which overall job attitudes (i.e., job satisfaction and organizational commitment) and overall personal health (i.e., physical and psychological health) fully mediate the relations between exposure to psychological aggression at work and both task performance and contextual performance. Data were obtained from a national probability sample of US workers (N = 2376) and the model was tested using structural equation modelling. The results supported the hypothesized model, demonstrating that exposure to psychological aggression at work negatively predicted both task performance and contextual performance, and that these relations were explained by decrements in job attitudes and health associated with exposure to psychological aggression at work.

Nonisentropic unsteady three dimensional small disturbance potential theory

NASA Technical Reports Server (NTRS)

Gibbons, M. D.; Whitlow, W., Jr.; Williams, M. H.

1986-01-01

Modifications that allow for more accurate modeling of flow fields when strong shocks are present were made into three dimensional transonic small disturbance (TSD) potential theory. The Engquist-Osher type-dependent differencing was incorporated into the solution algorithm. The modified theory was implemented in the XTRAN3S computer code. Steady flows over a rectangular wing with a constant NACA 0012 airfoil section and an aspect ratio of 12 were calculated for freestream Mach numbers (M) of 0.82, 0.84, and 0.86. The obtained results are compared using the modified and unmodified TSD theories and the results from a three dimensional Euler code are presented. Nonunique solutions in three dimensions are shown to appear for the rectangular wing as aspect ratio increases. Steady and unsteady results are shown for the RAE tailplane model at M = 0.90. Calculations using unmodified theory, modified theory and experimental data are compared.

The Black-White-Other Achievement Gap: Testing Theories of Academic Performance among Multiracial and Monoracial Adolescents

ERIC Educational Resources Information Center

Herman, Melissa R.

2009-01-01

The study presented here tested three theories of racial differences in academic performance among monoracial and multiracial high school students. These theories (status attainment, oppositional culture, and educational attitudes) were developed to explain differences in achievement among monoracial groups, but the study tested how the theories…

A Selected Review of the Underpinnings of Ethics for Human Performance Technology Professionals--Part One: Key Ethical Theories and Research.

ERIC Educational Resources Information Center

Dean, Peter J.

1993-01-01

Provides a review of the key ethical theories and relevant empirical research relating to the practice of human performance technology. Topics addressed include ethics, morals, business ethics, ethics officers, empiricism versus normative ethical theory, consequentialism, utilitarianism, nonconsequentialism, Kohlberg model of cognitive moral…

Modelling Transposition Latencies: Constraints for Theories of Serial Order Memory

ERIC Educational Resources Information Center

Farrell, Simon; Lewandowsky, Stephan

2004-01-01

Several competing theories of short-term memory can explain serial recall performance at a quantitative level. However, most theories to date have not been applied to the accompanying pattern of response latencies, thus ignoring a rich and highly diagnostic aspect of performance. This article explores and tests the error latency predictions of…

The Effects of Racial Conflict on Organizational Performance: A Search for Theory

ERIC Educational Resources Information Center

Byrd, Marilyn Y.

2007-01-01

This article addresses the effect of racial conflict on organizational performance as an issue that needs theoretical support in the foundational theories of human resource development (HRD). While the field of HRD recognizes theories from multiple disciplines, the field lacks a theoretical framework to inform leadership in managing racial…

The Relation between Individual Differences in Fantasy and Theory of Mind.

ERIC Educational Resources Information Center

Taylor, Marjorie; Carlson, Stephanie M.

1997-01-01

Examined relation between early fantasy/pretense and knowledge about mental life in 3- and 4-year olds. Found that performance on theory of mind tasks was significantly intercorrelated when effects of verbal intelligence and age were statistically controlled. Individual differences in fantasy/pretense were related to theory of mind performance in…

Motivation across Domains: Do Goals and Attributions Change with Subject Matter for Grades 4 and 5 Students?

ERIC Educational Resources Information Center

Vogler, Jane S.; Bakken, Linda

2007-01-01

This study explored a theory for motivation which included aspects of both attribution theory and goal theory. Motivational variables included beliefs about intelligence (entity or incremental), goal orientation (mastery/learning, performance-approach, performance-avoidance) and avoidant behaviours. Grades 4 and 5 students from a large,…

Performance Enhancement of Unsteady Ejectors Investigated Using a Pulsejet Driver

NASA Technical Reports Server (NTRS)

Paxson, Daniel E.

2003-01-01

Unsteady ejectors are currently under investigation for use in some pulse detonation engine (PDE) propulsion systems. This is due primarily to their potential high performance in comparison to steady ejectors of similar dimensions relative to the source or driver jet. Although some experimental work has been done in the past to study thrust augmentation with unsteady ejectors, there is no proven theory by which optimal design parameters can be selected and an effective ejector constructed for a given pulsed flow. Therefore, an experimental facility was developed at the NASA Glenn Research Center to study the correlation between ejector design and performance, and to get a better understanding of the flow phenomena that result in thrust augmentation. A commercially available pulsejet was used for the unsteady driving jet. This was paired with a basic, yet flexible, ejector design that allowed parametric evaluation of the effects that length, diameter, and inlet radius have on performance.

Towards a new paradigm: Activity level balanced sustainability reporting.

PubMed

Samudhram, Ananda; Siew, Eu-Gene; Sinnakkannu, Jothee; Yeow, Paul H P

2016-11-01

Technoeconomic paradigms based economic growth theories suggest that waves of technological innovations drove the economic growth of advanced economies. Widespread economic degradation and pollution is an unintended consequence of such growth. Tackling environmental and social issues at firm levels would help us to overcome such issues at macro-levels. Consequently, the Triple Bottom Line (TBL) reporting approach promotes firm level economic, environmental and social performances. Incorporating Zink's (2014) 3-pillar presentation model, this paper indicates that economic, social and environmental performances tend to be reported at firm level. All three pillars are not covered evenly at the activity levels. Thus, a loophole is identified whereby excellent environmental performance at activity levels could potentially leave poor social performance undisclosed. A refinement of the TBL paradigm, whereby all three pillars are covered at the activity level, is suggested, to enhance sustainability reporting. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fast Screening Technology for Drug Emergency Management: Predicting Suspicious SNPs for ADR with Information Theory-based Models.

PubMed

Liang, Zhaohui; Liu, Jun; Huang, Jimmy X; Zeng, Xing

2018-01-01

The genetic polymorphism of Cytochrome P450 (CYP 450) is considered as one of the main causes for adverse drug reactions (ADRs). In order to explore the latent correlations between ADRs and potentially corresponding single-nucleotide polymorphism (SNPs) in CYP450, three algorithms based on information theory are used as the main method to predict the possible relation. The study uses a retrospective case-control study to explore the potential relation of ADRs to specific genomic locations and single-nucleotide polymorphism (SNP). The genomic data collected from 53 healthy volunteers are applied for the analysis, another group of genomic data collected from 30 healthy volunteers excluded from the study are used as the control group. The SNPs respective on five loci of CYP2D6*2,*10,*14 and CYP1A2*1C, *1F are detected by the Applied Biosystem 3130xl. The raw data is processed by ChromasPro to detect the specific alleles on the above loci from each sample. The secondary data are reorganized and processed by R combined with the reports of ADRs from clinical reports. Three information theory based algorithms are implemented for the screening task: JMI, CMIM, and mRMR. If a SNP is selected by more than two algorithms, we are confident to conclude that it is related to the corresponding ADR. The selection results are compared with the control decision tree + LASSO regression model. In the study group where ADRs occur, 10 SNPs are considered relevant to the occurrence of a specific ADR by the combined information theory model. In comparison, only 5 SNPs are considered relevant to a specific ADR by the decision tree + LASSO regression model. In addition, the new method detects more relevant pairs of SNP and ADR which are affected by both SNP and dosage. This implies that the new information theory based model is effective to discover correlations of ADRs and CYP 450 SNPs and is helpful in predicting the potential vulnerable genotype for some ADRs. The newly proposed information theory based model has superiority performance in detecting the relation between SNP and ADR compared to the decision tree + LASSO regression model. The new model is more sensitive to detect ADRs compared to the old method, while the old method is more reliable. Therefore, the selection criteria for selecting algorithms should depend on the pragmatic needs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A theoretical study of the adiabatic and vertical ionization potentials of water.

PubMed

Feller, David; Davidson, Ernest R

2018-06-21

Theoretical predictions of the three lowest adiabatic and vertical ionization potentials of water were obtained from the Feller-Peterson-Dixon approach. This approach combines multiple levels of coupled cluster theory with basis sets as large as aug-cc-pV8Z in some cases and various corrections up to and including full configuration interaction theory. While agreement with experiment for the adiabatic ionization potential of the lowest energy 2 B 1 state was excellent, differences for other states were much larger, sometimes exceeding 10 kcal/mol (0.43 eV). Errors of this magnitude are inconsistent with previous benchmark work on 52 adiabatic ionization potentials, where a root mean square of 0.20 kcal/mol (0.009 eV) was found. Difficulties in direct comparisons between theory and experiment for vertical ionization potentials are discussed. With regard to the differences found for the 2 A 1 / 2 Π u and 2 B 2 adiabatic ionization potentials, a reinterpretation of the experimental spectrum appears justified.

Item response theory and the measurement of motor behavior.

PubMed

Safrit, M J; Cohen, A S; Costa, M G

1989-12-01

Item response theory (IRT) has been the focus of intense research and development activity in educational and psychological measurement during the past decade. Because this theory can provide more precise information about test items than other theories usually used in measuring motor behavior, the application of IRT in physical education and exercise science merits investigation. In IRT, the difficulty level of each item (e.g., trial or task) can be estimated and placed on the same scale as the ability of the examinee. Using this information, the test developer can determine the ability levels at which the test functions best. Equating the scores of individuals on two or more items or tests can be handled efficiently by applying IRT. The precision of the identification of performance standards in a mastery test context can be enhanced, as can adaptive testing procedures. In this tutorial, several potential benefits of applying IRT to the measurement of motor behavior were described. An example is provided using bowling data and applying the graded-response form of the Rasch IRT model. The data were calibrated and the goodness of fit was examined. This analysis is described in a step-by-step approach. Limitations to using an IRT model with a test consisting of repeated measures were noted.

Theory for the three-dimensional Mercedes-Benz model of water.

PubMed

Bizjak, Alan; Urbic, Tomaz; Vlachy, Vojko; Dill, Ken A

2009-11-21

The two-dimensional Mercedes-Benz (MB) model of water has been widely studied, both by Monte Carlo simulations and by integral equation methods. Here, we study the three-dimensional (3D) MB model. We treat water as spheres that interact through Lennard-Jones potentials and through a tetrahedral Gaussian hydrogen bonding function. As the "right answer," we perform isothermal-isobaric Monte Carlo simulations on the 3D MB model for different pressures and temperatures. The purpose of this work is to develop and test Wertheim's Ornstein-Zernike integral equation and thermodynamic perturbation theories. The two analytical approaches are orders of magnitude more efficient than the Monte Carlo simulations. The ultimate goal is to find statistical mechanical theories that can efficiently predict the properties of orientationally complex molecules, such as water. Also, here, the 3D MB model simply serves as a useful workbench for testing such analytical approaches. For hot water, the analytical theories give accurate agreement with the computer simulations. For cold water, the agreement is not as good. Nevertheless, these approaches are qualitatively consistent with energies, volumes, heat capacities, compressibilities, and thermal expansion coefficients versus temperature and pressure. Such analytical approaches offer a promising route to a better understanding of water and also the aqueous solvation.

Theory for the three-dimensional Mercedes-Benz model of water

PubMed Central

Bizjak, Alan; Urbic, Tomaz; Vlachy, Vojko; Dill, Ken A.

2009-01-01

The two-dimensional Mercedes-Benz (MB) model of water has been widely studied, both by Monte Carlo simulations and by integral equation methods. Here, we study the three-dimensional (3D) MB model. We treat water as spheres that interact through Lennard-Jones potentials and through a tetrahedral Gaussian hydrogen bonding function. As the “right answer,” we perform isothermal-isobaric Monte Carlo simulations on the 3D MB model for different pressures and temperatures. The purpose of this work is to develop and test Wertheim’s Ornstein–Zernike integral equation and thermodynamic perturbation theories. The two analytical approaches are orders of magnitude more efficient than the Monte Carlo simulations. The ultimate goal is to find statistical mechanical theories that can efficiently predict the properties of orientationally complex molecules, such as water. Also, here, the 3D MB model simply serves as a useful workbench for testing such analytical approaches. For hot water, the analytical theories give accurate agreement with the computer simulations. For cold water, the agreement is not as good. Nevertheless, these approaches are qualitatively consistent with energies, volumes, heat capacities, compressibilities, and thermal expansion coefficients versus temperature and pressure. Such analytical approaches offer a promising route to a better understanding of water and also the aqueous solvation. PMID:19929057

Theory for the three-dimensional Mercedes-Benz model of water

NASA Astrophysics Data System (ADS)

Bizjak, Alan; Urbic, Tomaz; Vlachy, Vojko; Dill, Ken A.

2009-11-01

The two-dimensional Mercedes-Benz (MB) model of water has been widely studied, both by Monte Carlo simulations and by integral equation methods. Here, we study the three-dimensional (3D) MB model. We treat water as spheres that interact through Lennard-Jones potentials and through a tetrahedral Gaussian hydrogen bonding function. As the "right answer," we perform isothermal-isobaric Monte Carlo simulations on the 3D MB model for different pressures and temperatures. The purpose of this work is to develop and test Wertheim's Ornstein-Zernike integral equation and thermodynamic perturbation theories. The two analytical approaches are orders of magnitude more efficient than the Monte Carlo simulations. The ultimate goal is to find statistical mechanical theories that can efficiently predict the properties of orientationally complex molecules, such as water. Also, here, the 3D MB model simply serves as a useful workbench for testing such analytical approaches. For hot water, the analytical theories give accurate agreement with the computer simulations. For cold water, the agreement is not as good. Nevertheless, these approaches are qualitatively consistent with energies, volumes, heat capacities, compressibilities, and thermal expansion coefficients versus temperature and pressure. Such analytical approaches offer a promising route to a better understanding of water and also the aqueous solvation.

Pragmatic hydraulic theory predicts stomatal responses to climatic water deficits.

PubMed

Sperry, John S; Wang, Yujie; Wolfe, Brett T; Mackay, D Scott; Anderegg, William R L; McDowell, Nate G; Pockman, William T

2016-11-01

Ecosystem models have difficulty predicting plant drought responses, partially from uncertainty in the stomatal response to water deficits in soil and atmosphere. We evaluate a 'supply-demand' theory for water-limited stomatal behavior that avoids the typical scaffold of empirical response functions. The premise is that canopy water demand is regulated in proportion to threat to supply posed by xylem cavitation and soil drying. The theory was implemented in a trait-based soil-plant-atmosphere model. The model predicted canopy transpiration (E), canopy diffusive conductance (G), and canopy xylem pressure (P canopy ) from soil water potential (P soil ) and vapor pressure deficit (D). Modeled responses to D and P soil were consistent with empirical response functions, but controlling parameters were hydraulic traits rather than coefficients. Maximum hydraulic and diffusive conductances and vulnerability to loss in hydraulic conductance dictated stomatal sensitivity and hence the iso- to anisohydric spectrum of regulation. The model matched wide fluctuations in G and P canopy across nine data sets from seasonally dry tropical forest and piñon-juniper woodland with < 26% mean error. Promising initial performance suggests the theory could be useful in improving ecosystem models. Better understanding of the variation in hydraulic properties along the root-stem-leaf continuum will simplify parameterization. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Theories of behaviour and behaviour change across the social and behavioural sciences: a scoping review.

PubMed

Davis, Rachel; Campbell, Rona; Hildon, Zoe; Hobbs, Lorna; Michie, Susan

2015-01-01

Interventions to change health-related behaviours typically have modest effects and may be more effective if grounded in appropriate theory. Most theories applied to public health interventions tend to emphasise individual capabilities and motivation, with limited reference to context and social factors. Intervention effectiveness may be increased by drawing on a wider range of theories incorporating social, cultural and economic factors that influence behaviour. The primary aim of this paper is to identify theories of behaviour and behaviour change of potential relevance to public health interventions across four scientific disciplines: psychology, sociology, anthropology and economics. We report in detail the methodology of our scoping review used to identify these theories including which involved a systematic search of electronic databases, consultation with a multidisciplinary advisory group, web searching, searching of reference lists and hand searching of key behavioural science journals. Of secondary interest we developed a list of agreed criteria for judging the quality of the theories. We identified 82 theories and 9 criteria for assessing theory quality. The potential relevance of this wide-ranging number of theories to public health interventions and the ease and usefulness of evaluating the theories in terms of the quality criteria are however yet to be determined.

Theories of behaviour and behaviour change across the social and behavioural sciences: a scoping review

PubMed Central

Davis, Rachel; Campbell, Rona; Hildon, Zoe; Hobbs, Lorna; Michie, Susan

2015-01-01

Interventions to change health-related behaviours typically have modest effects and may be more effective if grounded in appropriate theory. Most theories applied to public health interventions tend to emphasise individual capabilities and motivation, with limited reference to context and social factors. Intervention effectiveness may be increased by drawing on a wider range of theories incorporating social, cultural and economic factors that influence behaviour. The primary aim of this paper is to identify theories of behaviour and behaviour change of potential relevance to public health interventions across four scientific disciplines: psychology, sociology, anthropology and economics. We report in detail the methodology of our scoping review used to identify these theories including which involved a systematic search of electronic databases, consultation with a multidisciplinary advisory group, web searching, searching of reference lists and hand searching of key behavioural science journals. Of secondary interest we developed a list of agreed criteria for judging the quality of the theories. We identified 82 theories and 9 criteria for assessing theory quality. The potential relevance of this wide-ranging number of theories to public health interventions and the ease and usefulness of evaluating the theories in terms of the quality criteria are however yet to be determined. PMID:25104107

A complete vibrational study on a potential environmental toxicant agent, the 3,3',4,4'-tetrachloroazobenzene combining the FTIR, FTRaman, UV-Visible and NMR spectroscopies with DFT calculations.

PubMed

Castillo, María V; Pergomet, Jorgelina L; Carnavale, Gustavo A; Davies, Lilian; Zinczuk, Juan; Brandán, Silvia A

2015-01-05

In this study 3,3',4,4'-tetrachloroazobenzene (TCAB) was prepared and then characterized by infrared, Raman, multidimensional nuclear magnetic resonance (NMR) and ultraviolet-visible spectroscopies. The density functional theory (DFT) together with the 6-31G(*) and 6-311++G(**) basis sets were used to study the structures and vibrational properties of the two cis and trans isomers of TCAB. The harmonic vibrational wavenumbers for the optimized geometries were calculated at the same theory levels. A complete assignment of all the observed bands in the vibrational spectra of TCAB was performed combining the DFT calculations with the scaled quantum mechanical force field (SQMFF) methodology. The molecular electrostatic potentials, atomic charges, bond orders and frontier orbitals for the two isomers of TCAB were compared and analyzed. The comparison of the theoretical ultraviolet-visible spectrum with the corresponding experimental demonstrates a good concordance while the calculated (1)H and (13)C chemicals shifts are in good conformity with the corresponding experimental NMR spectra of TCAB in solution. The npp(*) transitions for both forms were studied by natural bond orbital (NBO) while the topological properties were calculated by employing Bader's Atoms in the Molecules (AIM) theory. This study shows that the cis and trans isomers exhibit different structural and vibrational properties and absorption bands. Copyright © 2014. Published by Elsevier B.V.

Alternative separation of exchange and correlation energies in multi-configuration range-separated density-functional theory.

PubMed

Stoyanova, Alexandrina; Teale, Andrew M; Toulouse, Julien; Helgaker, Trygve; Fromager, Emmanuel

2013-10-07

The alternative separation of exchange and correlation energies proposed by Toulouse et al. [Theor. Chem. Acc. 114, 305 (2005)] is explored in the context of multi-configuration range-separated density-functional theory. The new decomposition of the short-range exchange-correlation energy relies on the auxiliary long-range interacting wavefunction rather than the Kohn-Sham (KS) determinant. The advantage, relative to the traditional KS decomposition, is that the wavefunction part of the energy is now computed with the regular (fully interacting) Hamiltonian. One potential drawback is that, because of double counting, the wavefunction used to compute the energy cannot be obtained by minimizing the energy expression with respect to the wavefunction parameters. The problem is overcome by using short-range optimized effective potentials (OEPs). The resulting combination of OEP techniques with wavefunction theory has been investigated in this work, at the Hartree-Fock (HF) and multi-configuration self-consistent-field (MCSCF) levels. In the HF case, an analytical expression for the energy gradient has been derived and implemented. Calculations have been performed within the short-range local density approximation on H2, N2, Li2, and H2O. Significant improvements in binding energies are obtained with the new decomposition of the short-range energy. The importance of optimizing the short-range OEP at the MCSCF level when static correlation becomes significant has also been demonstrated for H2, using a finite-difference gradient. The implementation of the analytical gradient for MCSCF wavefunctions is currently in progress.

Ar(n)HF van der Waals clusters revisited: II. Energetics and HF vibrational frequency shifts from diffusion Monte Carlo calculations on additive and nonadditive potential-energy surfaces for n=1-12.

PubMed

Jiang, Hao; Xu, Minzhong; Hutson, Jeremy M; Bacić, Zlatko

2005-08-01

The ground-state energies and HF vibrational frequency shifts of Ar(n)HF clusters have been calculated on the nonadditive potential-energy surfaces (PESs) for n=2-7 and on the pairwise-additive PESs for the clusters with n=1-12, using the diffusion Monte Carlo (DMC) method. For n>3, the calculations have been performed for the lowest-energy isomer and several higher-lying isomers which are the closest in energy. They provide information about the isomer dependence of the HF redshift, and enable direct comparison with the experimental data recently obtained in helium nanodroplets. The agreement between theory and experiment is excellent, in particular, for the nonadditive DMC redshifts. The relative, incremental redshifts are reproduced accurately even at the lower level of theory, i.e., the DMC and quantum five-dimensional (rigid Ar(n)) calculations on the pairwise-additive PESs. The nonadditive interactions make a significant contribution to the frequency shift, on the order of 10%-12%, and have to be included in the PESs in order for the theory to yield accurate magnitude of the HF redshift. The energy gaps between the DMC ground states of the cluster isomers are very different from the energy separation of their respective minima on the PES, due to the considerable variations in the intermolecular zero-point energy of different Ar(n)HF isomers.

The 'realities' of part-time nursing: a grounded theory study.

PubMed

Jamieson, Lynn N; Williams, Leonie Mosel; Lauder, William; Dwyer, Trudy

2008-10-01

To develop a theory that explains the 'realities' of part-time nursing. While little is known about the phenomenon of part-time nursing, increasing numbers of nurses work in part-time employment. Grounded theory. The problem that part-time nurses shared was an inability to achieve their personal optimal nursing potential. Motivators to work part-time, employment hours, specialty, individual and organizational factors formed contextual conditions that led to this problem. Part-time nurses responded to the challenges through a process of adaptation and adjustment. Harnessing the full productive potential of part-time nurses requires support to limit the difficulties that they encounter. The developed theory provides a valuable guide to managerial action. Nurse Managers need to consider the developed substantive theory when planning and managing nursing workforces.

Numerical Predictions of Damage and Failure in Carbon Fiber Reinforced Laminates Using a Thermodynamically-Based Work Potential Theory

NASA Technical Reports Server (NTRS)

Pineda, Evan Jorge; Waas, Anthony M.

2013-01-01

A thermodynamically-based work potential theory for modeling progressive damage and failure in fiber-reinforced laminates is presented. The current, multiple-internal state variable (ISV) formulation, referred to as enhanced Schapery theory (EST), utilizes separate ISVs for modeling the effects of damage and failure. Consistent characteristic lengths are introduced into the formulation to govern the evolution of the failure ISVs. Using the stationarity of the total work potential with respect to each ISV, a set of thermodynamically consistent evolution equations for the ISVs are derived. The theory is implemented into a commercial finite element code. The model is verified against experimental results from two laminated, T800/3900-2 panels containing a central notch and different fiber-orientation stacking sequences. Global load versus displacement, global load versus local strain gage data, and macroscopic failure paths obtained from the models are compared against the experimental results.

Lineshape theory of pigment-protein complexes: How the finite relaxation time of nuclei influences the exciton relaxation-induced lifetime broadening.

PubMed

Dinh, Thanh-Chung; Renger, Thomas

2016-07-21

In pigment-protein complexes, often the excited states are partially delocalized and the exciton-vibrational coupling in the basis of delocalized states contains large diagonal and small off-diagonal elements. This inequality may be used to introduce potential energy surfaces (PESs) of exciton states and to treat the inter-PES coupling in Markov and secular approximations. The resulting lineshape function consists of a Lorentzian peak that is broadened by the finite lifetime of the exciton states caused by the inter-PES coupling and a vibrational sideband that results from the mutual displacement of the excitonic PESs with respect to that of the ground state. So far analytical expressions have been derived that relate the exciton relaxation-induced lifetime broadening to the Redfield [T. Renger and R. A. Marcus, J. Chem. Phys. 116, 9997 (2002)] or modified Redfield [M. Schröder, U. Kleinekathöfer, and M. Schreiber, J. Chem. Phys. 124, 084903 (2006)] rate constants of exciton relaxation, assuming that intra-PES nuclear relaxation is fast compared to inter-PES transfer. Here, we go beyond this approximation and provide an analytical expression, termed Non-equilibrium Modified Redfield (NeMoR) theory, for the lifetime broadening that takes into account the finite nuclear relaxation time. In an application of the theory to molecular dimers, we find that, for a widely used experimental spectral density of the exciton-vibrational coupling of pigment-protein complexes, the NeMoR spectrum at low-temperatures (T < 150 K) is better approximated by Redfield than by modified Redfield theory. At room temperature, the lifetime broadening obtained with Redfield theory underestimates the NeMoR broadening, whereas modified Redfield theory overestimates it by a similar amount. A fortuitous error compensation in Redfield theory is found to explain the good performance of this theory at low temperatures. Since steady state spectra of PPCs are often measured at low temperatures, Redfield theory still provides a numerically efficient alternative to NeMoR theory. At higher temperatures, we suggest to use NeMoR theory, because it has the same numerical costs as modified Redfield theory, but is more accurate.

Behavioral and Social Sciences Theories and Models: Are They Used in Unintentional Injury Prevention Research?

ERIC Educational Resources Information Center

Trifiletti, L. B.; Gielen, A. C.; Sleet, D. A.; Hopkins, K.

2005-01-01

Behavioral and social sciences theories and models have the potential to enhance efforts to reduce unintentional injuries. The authors reviewed the published literature on behavioral and social science theory applications to unintentional injury problems to enumerate and categorize the ways different theories and models are used in injury…

Art as Relational Encounter: An Ostensive Communication Theory of Art Therapy

ERIC Educational Resources Information Center

Springham, Neil; Huet, Val

2018-01-01

Biopsychosocial theory is strengthening psychotherapy by focusing on interactions that engage the attachment system. Art therapy has the potential to align coherently with current theory provided it addresses the value of art in engaging with the attachment system. This article describes an interpersonal theory of art therapy based on a model of…

Generative Insights from the Eleanor Chelimsky Forum on Evaluation Theory and Practice

ERIC Educational Resources Information Center

Leviton, Laura C.

2014-01-01

Both speakers at the Eleanor Chelimsky Forum on Theory and Practice in Evaluation pointed out the complexity and messiness of evaluation practice, and thus potential limits on theory and generalizable knowledge. The concept of reflective practice offers one way forward to build evaluation theory. Building generalizable knowledge about practice…

Parables and paradigms: an introduction to using communication theories in outdoor recreation research

Treesearch

James Absher

1998-01-01

Studies that employ communication theories are rare in recreation resource management. One reason may be unfamiliarity with communication theories and their potential to provide useful results. A two-dimensional metatheoretical plane is proposed, selected recreation and communication theories are located in it, and functional comparisons are made among eight disparate...

Applications of Balance Theory to Faculty Effectiveness: An Assessment

ERIC Educational Resources Information Center

Peterson, Robin T.; Limbu, Yam B.; Xu, Bing; Fischbach, Sarah

2012-01-01

This paper provides a critical examination of the potential role of balance theory and student liking (affect) of instructors as tools for marketing professors in assisting student learning. The nature of balance theory and evidence of the learning impact of affect toward instructors are discussed. An empirical test of the theory is provided, and…

Group contribution methodology based on the statistical associating fluid theory for heteronuclear molecules formed from Mie segments.

PubMed

Papaioannou, Vasileios; Lafitte, Thomas; Avendaño, Carlos; Adjiman, Claire S; Jackson, George; Müller, Erich A; Galindo, Amparo

2014-02-07

A generalization of the recent version of the statistical associating fluid theory for variable range Mie potentials [Lafitte et al., J. Chem. Phys. 139, 154504 (2013)] is formulated within the framework of a group contribution approach (SAFT-γ Mie). Molecules are represented as comprising distinct functional (chemical) groups based on a fused heteronuclear molecular model, where the interactions between segments are described with the Mie (generalized Lennard-Jonesium) potential of variable attractive and repulsive range. A key feature of the new theory is the accurate description of the monomeric group-group interactions by application of a high-temperature perturbation expansion up to third order. The capabilities of the SAFT-γ Mie approach are exemplified by studying the thermodynamic properties of two chemical families, the n-alkanes and the n-alkyl esters, by developing parameters for the methyl, methylene, and carboxylate functional groups (CH3, CH2, and COO). The approach is shown to describe accurately the fluid-phase behavior of the compounds considered with absolute average deviations of 1.20% and 0.42% for the vapor pressure and saturated liquid density, respectively, which represents a clear improvement over other existing SAFT-based group contribution approaches. The use of Mie potentials to describe the group-group interaction is shown to allow accurate simultaneous descriptions of the fluid-phase behavior and second-order thermodynamic derivative properties of the pure fluids based on a single set of group parameters. Furthermore, the application of the perturbation expansion to third order for the description of the reference monomeric fluid improves the predictions of the theory for the fluid-phase behavior of pure components in the near-critical region. The predictive capabilities of the approach stem from its formulation within a group-contribution formalism: predictions of the fluid-phase behavior and thermodynamic derivative properties of compounds not included in the development of group parameters are demonstrated. The performance of the theory is also critically assessed with predictions of the fluid-phase behavior (vapor-liquid and liquid-liquid equilibria) and excess thermodynamic properties of a variety of binary mixtures, including polymer solutions, where very good agreement with the experimental data is seen, without the need for adjustable mixture parameters.

ERP Reliability Analysis (ERA) Toolbox: An open-source toolbox for analyzing the reliability of event-related brain potentials.

PubMed

Clayson, Peter E; Miller, Gregory A

2017-01-01

Generalizability theory (G theory) provides a flexible, multifaceted approach to estimating score reliability. G theory's approach to estimating score reliability has important advantages over classical test theory that are relevant for research using event-related brain potentials (ERPs). For example, G theory does not require parallel forms (i.e., equal means, variances, and covariances), can handle unbalanced designs, and provides a single reliability estimate for designs with multiple sources of error. This monograph provides a detailed description of the conceptual framework of G theory using examples relevant to ERP researchers, presents the algorithms needed to estimate ERP score reliability, and provides a detailed walkthrough of newly-developed software, the ERP Reliability Analysis (ERA) Toolbox, that calculates score reliability using G theory. The ERA Toolbox is open-source, Matlab software that uses G theory to estimate the contribution of the number of trials retained for averaging, group, and/or event types on ERP score reliability. The toolbox facilitates the rigorous evaluation of psychometric properties of ERP scores recommended elsewhere in this special issue. Copyright © 2016 Elsevier B.V. All rights reserved.

The Chicken or the Egg? The Direction of the Relationship Between Mathematics Anxiety and Mathematics Performance.

PubMed

Carey, Emma; Hill, Francesca; Devine, Amy; Szücs, Dénes

2015-01-01

This review considers the two possible causal directions between mathematics anxiety (MA) and poor mathematics performance. Either poor maths performance may elicit MA (referred to as the Deficit Theory), or MA may reduce future maths performance (referred to as the Debilitating Anxiety Model). The evidence is in conflict: the Deficit Theory is supported by longitudinal studies and studies of children with mathematical learning disabilities, but the Debilitating Anxiety Model is supported by research which manipulates anxiety levels and observes a change in mathematics performance. It is suggested that this mixture of evidence might indicate a bidirectional relationship between MA and mathematics performance (the Reciprocal Theory), in which MA and mathematics performance can influence one another in a vicious cycle.

Researching pharmacist managerial capability: philosophical perspectives and paradigms of inquiry.

PubMed

Woods, Phillip; Gapp, Rod; King, Michelle A

2015-01-01

In successful community pharmacy business enterprises suitably responsive actions to meet ever-increasing change require capable pharmacy managers who readily learn and adapt. Capability as a concept is generally understood to be the ability of a manager to identify and act to solve unfamiliar problems in unfamiliar situations. Capability is characterized by adaptability and flexibility. However, different understandings of the concept 'capability' and what it means to be 'capable' are indirect and incomplete. This paper aims to clarify current theories regarding the concept of 'capability' at the level of the individual, and through this to make more explicit what is known about the phenomenon, but more particularly, how we know what we know. The analysis includes the concept of 'competence' because explanations of capability include competence, and the two concepts are not clearly separated in the literature. By probing the epistemological origins of current theory concerning both concepts, the limiting taken for granted assumptions are revealed. Assumptions about context and time, and the psychological theory through which individuals are assumed to perceive, know and learn, are illuminated. The analysis, in connection with the literature, shows how the interpretive philosophic research approach may reveal a different and useful theoretical perspective for explaining capability as a dynamic performance. It is suggested that such a perspective may narrow the gap between the theory of capability and its practice. The interpretive perspective holds potential to reveal how capability, as performed by successful community pharmacy managers, might be further researched and strengthened. This paper supports the challenging suggestion that pharmacy social research needs to rebalance the dominance of purely empirical research by exploring interpretive methodologies to better understand human actions and relations in the context of pharmacy. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Influence of pressure on the crystallization of systems characterized by different intermolecular attraction

NASA Astrophysics Data System (ADS)

Koperwas, K.; Affouard, F.; Gerges, J.; Valdes, L.-C.; Adrjanowicz, K.; Paluch, M.

2017-12-01

In this paper, we examine, in terms of the classical nucleation theory, how the strengthening of the attractive intermolecular interactions influences the crystallization process for systems like Lennard-Jones at different isobaric conditions. For this purpose, we modify the standard Lennard-Jones potential, and as a result, we obtain three different systems characterized by various strengths of attractive potentials occurring between molecules, which are in direct relationship to the physical quantities describing molecules, e.g., its polarizability or dipole moment. Based on performed analysis, we demonstrate that the molecular attraction primarily impacts the thermodynamics of the interface between liquid and crystal. This is reflected in the behavior of nucleation and overall crystallization rates during compression of the system.

The relationship between vocabulary, grammar, and false belief task performance in children with autistic spectrum disorders and children with moderate learning difficulties.

PubMed

Fisher, Naomi; Happé, Francesca; Dunn, Judy

2005-04-01

The aim of this study was to examine the relationship between language and theory of mind in children with autistic spectrum disorders (ASD) and children with moderate learning difficulties (MLD). Previous studies have found a strong association between language and theory of mind in a range of groups, but mostly have not included measures of both grammar and vocabulary; including these enables us to speculate about the causal direction of the relationship. Fifty-eight children with ASD and 118 children with MLD were given standardised assessments of vocabulary and grammar, along with standard theory of mind tasks. The relationship between language and theory of mind was more evident in children with ASD than in those with MLD, and grammar was a particularly strong predictor of theory of mind performance in children with ASD. Children with MLD performed better on false belief (FB) tasks than did children with ASD, and their performance was more predictable across the different theory of mind tasks. Language, in particular grammar, and theory of mind appear to be more strongly related in children with ASD than in those with MLD. We speculate that this relationship may be causal, with some grammatical understanding being a precursor of theory of mind. The implications of these findings are discussed in relation to possible routes for compensatory strategies for mentalising in children with ASD.

Theory, practice and performance

NASA Astrophysics Data System (ADS)

Gallagher, Shaun

2017-01-01

I focus on the enactivist and extended mind approaches to embodied cognition (EC), and specifically on the concepts of body schema, affectivity, distributed cognition and intersubjectivity to show how EC has relevance to questions about expert performance, and to the theory and practice of performing arts.

Managerial Perceptions of Performance: A Comparison of Japanese and American Work Groups.

ERIC Educational Resources Information Center

Sullivan, Jeremiah J.; And Others

1986-01-01

Identifies various theories of individual and group influences on the performance control process. Both Japanese and American managers have a Rational Man theory of the individual. However, Americans see groups as helping to reduce the risk of poor performance, whereas Japanese see them as enhancing good performance. (Author/LHW)

Construction of the landscape for multi-stable systems: Potential landscape, quasi-potential, A-type integral and beyond

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

Zhou, Peijie, E-mail: cliffzhou@pku.edu.cn; Li, Tiejun, E-mail: tieli@pku.edu.cn

Motivated by the famous Waddington’s epigenetic landscape metaphor in developmental biology, biophysicists and applied mathematicians made different proposals to construct the landscape for multi-stable complex systems. We aim to summarize and elucidate the relationships among these theories from a mathematical point of view. We systematically investigate and compare three different but closely related realizations in the recent literature: the Wang’s potential landscape theory from steady state distribution of stochastic differential equations (SDEs), the Freidlin-Wentzell quasi-potential from the large deviation theory, and the construction through SDE decomposition and A-type integral. We revisit that the quasi-potential is the zero noise limit ofmore » the potential landscape, and the potential function in the third proposal coincides with the quasi-potential. We compare the difference between local and global quasi-potential through the viewpoint of exchange of limit order for time and noise amplitude. We argue that local quasi-potentials are responsible for getting transition rates between neighboring stable states, while the global quasi-potential mainly characterizes the residence time of the states as the system reaches stationarity. The difference between these two is prominent when the transitivity property is broken. The most probable transition path by minimizing the Onsager-Machlup or Freidlin-Wentzell action functional is also discussed. As a consequence of the established connections among different proposals, we arrive at the novel result which guarantees the existence of SDE decomposition while denies its uniqueness in general cases. It is, therefore, clarified that the A-type integral is more appropriate to be applied to the decomposed SDEs rather than its primitive form as believed by previous researchers. Our results contribute to a deeper understanding of landscape theories for biological systems.« less

Construction of the landscape for multi-stable systems: Potential landscape, quasi-potential, A-type integral and beyond

NASA Astrophysics Data System (ADS)

Zhou, Peijie; Li, Tiejun

2016-03-01

Motivated by the famous Waddington's epigenetic landscape metaphor in developmental biology, biophysicists and applied mathematicians made different proposals to construct the landscape for multi-stable complex systems. We aim to summarize and elucidate the relationships among these theories from a mathematical point of view. We systematically investigate and compare three different but closely related realizations in the recent literature: the Wang's potential landscape theory from steady state distribution of stochastic differential equations (SDEs), the Freidlin-Wentzell quasi-potential from the large deviation theory, and the construction through SDE decomposition and A-type integral. We revisit that the quasi-potential is the zero noise limit of the potential landscape, and the potential function in the third proposal coincides with the quasi-potential. We compare the difference between local and global quasi-potential through the viewpoint of exchange of limit order for time and noise amplitude. We argue that local quasi-potentials are responsible for getting transition rates between neighboring stable states, while the global quasi-potential mainly characterizes the residence time of the states as the system reaches stationarity. The difference between these two is prominent when the transitivity property is broken. The most probable transition path by minimizing the Onsager-Machlup or Freidlin-Wentzell action functional is also discussed. As a consequence of the established connections among different proposals, we arrive at the novel result which guarantees the existence of SDE decomposition while denies its uniqueness in general cases. It is, therefore, clarified that the A-type integral is more appropriate to be applied to the decomposed SDEs rather than its primitive form as believed by previous researchers. Our results contribute to a deeper understanding of landscape theories for biological systems.

Blowing bubbles in Lennard-Jonesium along the saturation curve.

PubMed

Ashbaugh, Henry S

2009-05-28

Extensive molecular simulations of the Lennard-Jones fluid have been performed to determine its liquid-vapor coexistence properties and solvent contact densities with cavities up to ten times the diameter of the solvent from the triple point to the critical point. These simulations are analyzed using a revised scaled-particle theory [H. S. Ashbaugh and L. R. Pratt, Rev. Mod. Phys. 78, 159 (2006)] to evaluate the thermodynamics of cavity solvation and curvature dependent interfacial properties along the saturation curve. While the thermodynamic signatures of cavity solvation are distinct from those in water, exhibiting a chemical potential dominated by a large temperature independent enthalpy, the solvent dewets cavities of increasing size similar with water near coexistence. The interfacial tension for forming a liquid-wall interface is found to be consistently greater than the liquid-vapor surface tension of the Lennard-Jones fluid by up to 10% and potentially reflects the suppression of high amplitude fluctuations at the cavity surface. The first-order curvature correction for the surface tension is negative and appears to diverge to negative infinity at temperatures approaching the critical point. Our results point to the success of the revised scaled-particle theory at bridging molecular and macroscopic descriptions of cavity solvation.