Perturbed period-doubling bifurcation. I. Theory
DEFF Research Database (Denmark)
Svensmark, Henrik; Samuelsen, Mogens Rugholm
1990-01-01
-defined way that is a function of the amplitude and the frequency of the signal. New scaling laws between the amplitude of the signal and the detuning δ are found; these scaling laws apply to a variety of quantities, e.g., to the shift of the bifurcation point. It is also found that the stability...... of a microwave-driven Josephson junction confirm the theory. Results should be of interest in parametric-amplification studies....
Dynamical systems V bifurcation theory and catastrophe theory
1994-01-01
Bifurcation theory and catastrophe theory are two of the best known areas within the field of dynamical systems. Both are studies of smooth systems, focusing on properties that seem to be manifestly non-smooth. Bifurcation theory is concerned with the sudden changes that occur in a system when one or more parameters are varied. Examples of such are familiar to students of differential equations, from phase portraits. Moreover, understanding the bifurcations of the differential equations that describe real physical systems provides important information about the behavior of the systems. Catastrophe theory became quite famous during the 1970's, mostly because of the sensation caused by the usually less than rigorous applications of its principal ideas to "hot topics", such as the characterization of personalities and the difference between a "genius" and a "maniac". Catastrophe theory is accurately described as singularity theory and its (genuine) applications. The authors of this book, the first printing of w...
Phase diagram of N = 2 superconformal field theories and bifurcation sets in catastrophe theory
International Nuclear Information System (INIS)
Kei Ito.
1989-08-01
Phase diagrams of N=2 superconformal field theories are mapped out. It is shown that they coincide with bifurcation sets in catastrophe theory. The results are applied to the determination of renormalization group flows triggered by a combination of two or more relevant operators. (author). 13 refs, 2 figs
Prolegomena to a theory of bifurcating universes
International Nuclear Information System (INIS)
Banks, T.; California Univ., Santa Cruz
1988-01-01
We outline a framework for describing the bifurcation of the universe into disconnected pieces, and formulate criteria for a system in which such phenomena occur, to describe local quantum physics in a single connected universe. The formalism is a four-dimensional analog of string field theory which we call Universal Field Theory (UFT). We argue that local dynamics in a single universe is a good approximation to UFT if the universal field is classical and if the vertex for emission of a new connected component of the universe is concentrated on universes of small volume. We show that classical UFT is equivalent to a Wheeler-DeWitt equation for a single connected universe plus a set of nonlocal gap equations for the couplings in the spacetime lagrangian. The effective action must be stationary with respect to the couplings. Nonlocality shows up only at short distances. We solve the equation for the low-energy cosmological constant and show that if the universe undergoes substantial inflation then the cosmological constant is determined to be negative and very small. Its precise value may depend on the fate of nonrelativistic matter in the very late stages of universal expansion. Finally, we argue that corrections to the classical UFT are nonlocal and must be suppressed if the theory is to make sense. This may be the reason that supersymmetric vacua of string theory are not realized in nature. (orig.)
The Effects of Machine Components on Bifurcation and Chaos as Applied to Multimachine System
Alomari, M. M.; Rodanski, B. S.
The second system of the IEEE second benchmark model of Subsynchronous Resonance (SSR) is considered. The system can be mathematically modeled as a set of first order nonlinear ordinary differential equations with the compensation factor (µ = Xc/XL) as a bifurcation (control) parameter. So, bifurcation theory can be applied to nonlinear dynamical systems, which can be written as dx/dt = F(x; µ). The effects of machine components, i.e. damper winding, automatic voltage regulator (AVR), and power system stabilizer (PSS) on SSR in power system are studied. The results show that these components affect the locations, number and type of the Hopf bifurcations.
Bifurcation theory for hexagonal agglomeration in economic geography
Ikeda, Kiyohiro
2014-01-01
This book contributes to an understanding of how bifurcation theory adapts to the analysis of economic geography. It is easily accessible not only to mathematicians and economists, but also to upper-level undergraduate and graduate students who are interested in nonlinear mathematics. The self-organization of hexagonal agglomeration patterns of industrial regions was first predicted by the central place theory in economic geography based on investigations of southern Germany. The emergence of hexagonal agglomeration in economic geography models was envisaged by Krugman. In this book, after a brief introduction of central place theory and new economic geography, the missing link between them is discovered by elucidating the mechanism of the evolution of bifurcating hexagonal patterns. Pattern formation by such bifurcation is a well-studied topic in nonlinear mathematics, and group-theoretic bifurcation analysis is a well-developed theoretical tool. A finite hexagonal lattice is used to express uniformly distri...
A numerical study of crack initiation in a bcc iron system based on dynamic bifurcation theory
International Nuclear Information System (INIS)
Li, Xiantao
2014-01-01
Crack initiation under dynamic loading conditions is studied under the framework of dynamic bifurcation theory. An atomistic model for BCC iron is considered to explicitly take into account the detailed molecular interactions. To understand the strain-rate dependence of the crack initiation process, we first obtain the bifurcation diagram from a computational procedure using continuation methods. The stability transition associated with a crack initiation, as well as the connection to the bifurcation diagram, is studied by comparing direct numerical results to the dynamic bifurcation theory [R. Haberman, SIAM J. Appl. Math. 37, 69–106 (1979)].
1991-01-01
Dynamical Bifurcation Theory is concerned with the phenomena that occur in one parameter families of dynamical systems (usually ordinary differential equations), when the parameter is a slowly varying function of time. During the last decade these phenomena were observed and studied by many mathematicians, both pure and applied, from eastern and western countries, using classical and nonstandard analysis. It is the purpose of this book to give an account of these developments. The first paper, by C. Lobry, is an introduction: the reader will find here an explanation of the problems and some easy examples; this paper also explains the role of each of the other paper within the volume and their relationship to one another. CONTENTS: C. Lobry: Dynamic Bifurcations.- T. Erneux, E.L. Reiss, L.J. Holden, M. Georgiou: Slow Passage through Bifurcation and Limit Points. Asymptotic Theory and Applications.- M. Canalis-Durand: Formal Expansion of van der Pol Equation Canard Solutions are Gevrey.- V. Gautheron, E. Isambe...
The period adding and incrementing bifurcations: from rotation theory to applications
DEFF Research Database (Denmark)
Granados, Albert; Alseda, Lluis; Krupa, Maciej
2017-01-01
for maps on the circle. In the second scenario, symbolic sequences are obtained by consecutive attachment of a given symbolic block and the periods of periodic orbits are incremented by a constant term. It is called the period incrementing bifurcation, in its proof relies on results for maps...... on the interval. We also discuss the expanding cases, as some of the partial results found in the literature also hold when these maps lose contractiveness. The higher dimensional case is also discussed by means of quasi-contractions. We also provide applied examples in control theory, power electronics...
Niederreiter, Harald
2015-01-01
This textbook effectively builds a bridge from basic number theory to recent advances in applied number theory. It presents the first unified account of the four major areas of application where number theory plays a fundamental role, namely cryptography, coding theory, quasi-Monte Carlo methods, and pseudorandom number generation, allowing the authors to delineate the manifold links and interrelations between these areas. Number theory, which Carl-Friedrich Gauss famously dubbed the queen of mathematics, has always been considered a very beautiful field of mathematics, producing lovely results and elegant proofs. While only very few real-life applications were known in the past, today number theory can be found in everyday life: in supermarket bar code scanners, in our cars’ GPS systems, in online banking, etc. Starting with a brief introductory course on number theory in Chapter 1, which makes the book more accessible for undergraduates, the authors describe the four main application areas in Chapters...
Hopf bifurcation in an Internet congestion control model
International Nuclear Information System (INIS)
Li Chunguang; Chen Guanrong; Liao Xiaofeng; Yu Juebang
2004-01-01
We consider an Internet model with a single link accessed by a single source, which responds to congestion signals from the network, and study bifurcation of such a system. By choosing the gain parameter as a bifurcation parameter, we prove that Hopf bifurcation occurs. The stability of bifurcating periodic solutions and the direction of the Hopf bifurcation are determined by applying the normal form theory and the center manifold theorem. Finally, a numerical example is given to verify the theoretical analysis
Dekkers, Rob
2017-01-01
Offering an up-to-date account of systems theories and its applications, this book provides a different way of resolving problems and addressing challenges in a swift and practical way, without losing overview and grip on the details. From this perspective, it offers a different way of thinking in order to incorporate different perspectives and to consider multiple aspects of any given problem. Drawing examples from a wide range of disciplines, it also presents worked cases to illustrate the principles. The multidisciplinary perspective and the formal approach to modelling of systems and processes of ‘Applied Systems Theory’ makes it suitable for managers, engineers, students, researchers, academics and professionals from a wide range of disciplines; they can use this ‘toolbox’ for describing, analysing and designing biological, engineering and organisational systems as well as getting a better understanding of societal problems. This revised, updated and expanded second edition includes coverage of a...
Fixed-point bifurcation analysis in biological models using interval polynomials theory.
Rigatos, Gerasimos G
2014-06-01
The paper proposes a systematic method for fixed-point bifurcation analysis in circadian cells and similar biological models using interval polynomials theory. The stages for performing fixed-point bifurcation analysis in such biological systems comprise (i) the computation of fixed points as functions of the bifurcation parameter and (ii) the evaluation of the type of stability for each fixed point through the computation of the eigenvalues of the Jacobian matrix that is associated with the system's nonlinear dynamics model. Stage (ii) requires the computation of the roots of the characteristic polynomial of the Jacobian matrix. This problem is nontrivial since the coefficients of the characteristic polynomial are functions of the bifurcation parameter and the latter varies within intervals. To obtain a clear view about the values of the roots of the characteristic polynomial and about the stability features they provide to the system, the use of interval polynomials theory and particularly of Kharitonov's stability theorem is proposed. In this approach, the study of the stability of a characteristic polynomial with coefficients that vary in intervals is equivalent to the study of the stability of four polynomials with crisp coefficients computed from the boundaries of the aforementioned intervals. The efficiency of the proposed approach for the analysis of fixed-point bifurcations in nonlinear models of biological neurons is tested through numerical and simulation experiments.
Arnold, Vladimir I; Khesin, Boris; Marsden, Jerrold E; Varchenko, AN; Vassiliev, Victor A; Viro, Oleg Yanovich; Zakalyukin, Vladimir
2013-01-01
Vladimir Arnold was one of the great mathematical scientists of our time. He is famous for both the breadth and the depth of his work. At the same time he is one of the most prolific and outstanding mathematical authors. This second volume of his ""Collected Works"" focuses on hydrodynamics, bifurcation theory, and algebraic geometry.
Geometric Theory Predicts Bifurcations in Minimal Wiring Cost Trees in Biology Are Flat
Chindapol, Nol; Kaandorp, Jaap A.; De Schutter, Erik
2012-01-01
The complex three-dimensional shapes of tree-like structures in biology are constrained by optimization principles, but the actual costs being minimized can be difficult to discern. We show that despite quite variable morphologies and functions, bifurcations in the scleractinian coral Madracis and in many different mammalian neuron types tend to be planar. We prove that in fact bifurcations embedded in a spatial tree that minimizes wiring cost should lie on planes. This biologically motivated generalization of the classical mathematical theory of Euclidean Steiner trees is compatible with many different assumptions about the type of cost function. Since the geometric proof does not require any correlation between consecutive planes, we predict that, in an environment without directional biases, consecutive planes would be oriented independently of each other. We confirm this is true for many branching corals and neuron types. We conclude that planar bifurcations are characteristic of wiring cost optimization in any type of biological spatial tree structure. PMID:22557937
Applied Research and Social Theory
Hawkins, Darnell F.
1978-01-01
Applied research, as compared to basic nonapplied research, offers the potential for the development of unique insights into the nature of social theory. Cultural deprivation theorizing is used to illustrate the interplay between research and theory. (Author/CTM)
Applied multidimensional systems theory
Bose, Nirmal K
2017-01-01
Revised and updated, this concise new edition of the pioneering book on multidimensional signal processing is ideal for a new generation of students. Multidimensional systems or m-D systems are the necessary mathematical background for modern digital image processing with applications in biomedicine, X-ray technology and satellite communications. Serving as a firm basis for graduate engineering students and researchers seeking applications in mathematical theories, this edition eschews detailed mathematical theory not useful to students. Presentation of the theory has been revised to make it more readable for students, and introduce some new topics that are emerging as multidimensional DSP topics in the interdisciplinary fields of image processing. New topics include Groebner bases, wavelets, and filter banks.
Spieker, Matthew H.
2016-01-01
Some American high schools include Advanced Placement (AP) Music Theory within their course offerings. Students who pass the AP exam can receive college credit either as a music or humanities credit. An AP class, however, offers music students more than future college credit; it ultimately improves musicianship skills and promotes deeper…
Applied neutron resonance theory
International Nuclear Information System (INIS)
Froehner, F.H.
1978-07-01
Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (orig.) [de
Applied electromagnetic scattering theory
Osipov, Andrey A
2017-01-01
Besides classical applications (radar and stealth, antennas, microwave engineering), scattering and diffraction are enabling phenomena for some emerging research fields (artificial electromagnetic materials or metamaterials, terahertz technologies, electromagnetic aspects of nano-science). This book is a tutorial for advanced students who need to study diffraction theory. The textbook gives fundamental knowledge about scattering and diffraction of electromagnetic waves and provides some working examples of solutions for practical high-frequency scattering and diffraction problems. The book focuses on the most important diffraction effects and mechanisms influencing the scattering process and describes efficient and physically justified simulation methods - physical optics (PO) and the physical theory of diffraction (PTD) - applicable in typical remote sensing scenarios. The material is presented in a comprehensible and logical form, which relates the presented results to the basic principles of electromag...
Dekkers, Rob
2014-01-01
Offering an up-to-date account of systems theories and its applications, this book provides a different way of resolving problems and addressing challenges in a swift and practical way, without losing overview and not having a grip on the details. From this perspective, it offers a different way of thinking in order to incorporate different perspectives and to consider multiple aspects of any given problem. Drawing examples from a wide range of disciplines, it also presents worked cases to illustrate the principles. The multidisciplinary perspective and the formal approach to modelling of syst
Bifurcation and stability in Yang-Mills theory with sources
International Nuclear Information System (INIS)
Jackiw, R.
1979-06-01
A lecture is presented in which some recent work on solutions to classical Yang-Mills theory is discussed. The investigations summarized include the field equations with static, external sources. A pattern allowing a comprehensive description of the solutions and stability in dynamical systems are covered. A list of open questions and problems for further research is given. 20 references
Romeou, Z.; Neukirch, T.
2002-10-01
We present the results of an investigation of the relationship between the predictions made by linear MHD stability theory for instabilities of straight flux tube models of line-tied coronal loops and the bifurcations of the underlying MHD equilibria. It is found that contrary to the naive assumption that there should be a one-to-one correspondence between instability points and bifurcation points, such an one-to-one correspondence does not always exist. Using the Gold-Hoyle equilibrium as an illustrative example it is shown that additional axisymmetric bifurcations exist if the equilibrium bifurcations are calculated with Grad-Shafranov theory. In this case the onset of the m = 0-instability (sausage mode) corresponds to the second and not the first bifurcation point of the equilibrium sequence. No additional bifurcations have been found when Euler potentials are used, and in this case the first bifurcation coincides with the onset condition for the m = 0-instability. A possible reason for this difference are the different boundary conditions.
Degenerate Hopf bifurcation in a self-exciting Faraday disc dynamo
Indian Academy of Sciences (India)
Weiquan Pan
2017-05-31
May 31, 2017 ... 2Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Big Data Processing,. Yulin Normal University, Yulin 537000, Guangxi, People's Republic of ..... Now we apply the Hopf bifurcation theory to analyse the complex dynamical bifurcations. 4.1 Hopf bifurcation at E0.
International Nuclear Information System (INIS)
Bakasov, A.A.; Govorkov, B.B. Jr.
1990-08-01
The critical case in stability theory is the case when it is impossible to study the stability of solutions over the linear part of ordinary differential equations. This situation is usual at the bifurcation points. There exists a powerful and constructive approach to investigate the stability - the theory of critical cases created by Lyapunov. The famous Lorenz model is used in this article as an illustration of the power of the method (new results). (author). 27 refs
Hou, Saing Paul; Haddad, Wassim M; Meskin, Nader; Bailey, James M
2015-12-01
With the advances in biochemistry, molecular biology, and neurochemistry there has been impressive progress in understanding the molecular properties of anesthetic agents. However, there has been little focus on how the molecular properties of anesthetic agents lead to the observed macroscopic property that defines the anesthetic state, that is, lack of responsiveness to noxious stimuli. In this paper, we use dynamical system theory to develop a mechanistic mean field model for neural activity to study the abrupt transition from consciousness to unconsciousness as the concentration of the anesthetic agent increases. The proposed synaptic drive firing-rate model predicts the conscious-unconscious transition as the applied anesthetic concentration increases, where excitatory neural activity is characterized by a Poincaré-Andronov-Hopf bifurcation with the awake state transitioning to a stable limit cycle and then subsequently to an asymptotically stable unconscious equilibrium state. Furthermore, we address the more general question of synchronization and partial state equipartitioning of neural activity without mean field assumptions. This is done by focusing on a postulated subset of inhibitory neurons that are not themselves connected to other inhibitory neurons. Finally, several numerical experiments are presented to illustrate the different aspects of the proposed theory.
Applied Linguistics: The Challenge of Theory
McNamara, Tim
2015-01-01
Language has featured prominently in contemporary social theory, but the relevance of this fact to the concerns of Applied Linguistics, with its necessary orientation to practical issues of language in context, represents an ongoing challenge. This article supports the need for a greater engagement with theory in Applied Linguistics. It considers…
Advanced Learning Theories Applied to Leadership Development
2006-11-01
Center for Army Leadership Technical Report 2006-2 Advanced Learning Theories Applied to Leadership Development Christina Curnow...2006 5a. CONTRACT NUMBER W91QF4-05-F-0026 5b. GRANT NUMBER 4. TITLE AND SUBTITLE Advanced Learning Theories Applied to Leadership Development 5c...ABSTRACT This report describes the development and implementation of an application of advanced learning theories to leadership development. A
Geometric theory predicts bifurcations in minimal wiring cost trees in biology are flat
Kim, Y.; Sinclair, R.; Chindapol, N.; Kaandorp, J.A.; De Schutter, E.
2012-01-01
The complex three-dimensional shapes of tree-like structures in biology are constrained by optimization principles, but the actual costs being minimized can be difficult to discern. We show that despite quite variable morphologies and functions, bifurcations in the scleractinian coral Madracis and
Bifurcation methods of dynamical systems for generalized ...
Indian Academy of Sciences (India)
Compacton solution; periodic wave solution; periodic cusp wave solution; generalized KP-BBM equation. Abstract. By applying the bifurcation theory of dynamical system to the generalized KP-BBM equation, the phase portraits of the travelling wave system are obtained. It can be shown that singular straight line in the ...
Applied group theory selected readings in physics
Cracknell, Arthur P
1968-01-01
Selected Readings in Physics: Applied Group Theory provides information pertinent to the fundamental aspects of applied group theory. This book discusses the properties of symmetry of a system in quantum mechanics.Organized into two parts encompassing nine chapters, this book begins with an overview of the problem of elastic vibrations of a symmetric structure. This text then examines the numbers, degeneracies, and symmetries of the normal modes of vibration. Other chapters consider the conditions under which a polyatomic molecule can have a stable equilibrium configuration when its electronic
Energy Technology Data Exchange (ETDEWEB)
Peters, John W.; Miller, Anne-Frances; Jones, Anne K.; King, Paul W.; Adams, Michael W. W.
2016-04-01
Electron bifurcation is the recently recognized third mechanism of biological energy conservation. It simultaneously couples exergonic and endergonic oxidation-reduction reactions to circumvent thermodynamic barriers and minimize free energy loss. Little is known about the details of how electron bifurcating enzymes function, but specifics are beginning to emerge for several bifurcating enzymes. To date, those characterized contain a collection of redox cofactors including flavins and iron-sulfur clusters. Here we discuss the current understanding of bifurcating enzymes and the mechanistic features required to reversibly partition multiple electrons from a single redox site into exergonic and endergonic electron transfer paths.
Energy Technology Data Exchange (ETDEWEB)
Kolesnikov, R.A.; Krommes, J.A.
2005-09-22
The collisionless limit of the transition to ion-temperature-gradient-driven plasma turbulence is considered with a dynamical-systems approach. The importance of systematic analysis for understanding the differences in the bifurcations and dynamics of linearly damped and undamped systems is emphasized. A model with ten degrees of freedom is studied as a concrete example. A four-dimensional center manifold (CM) is analyzed, and fixed points of its dynamics are identified and used to predict a ''Dimits shift'' of the threshold for turbulence due to the excitation of zonal flows. The exact value of that shift in terms of physical parameters is established for the model; the effects of higher-order truncations on the dynamics are noted. Multiple-scale analysis of the CM equations is used to discuss possible effects of modulational instability on scenarios for the transition to turbulence in both collisional and collisionless cases.
Bifurcation analysis for a two-dimensional delayed discrete-time Hopfield neural network
International Nuclear Information System (INIS)
Kaslik, E.; Balint, St.
2007-01-01
In this paper, a bifurcation analysis is undertaken for a discrete-time Hopfield neural network with a single delay. Conditions ensuring the asymptotic stability of the null solution are found, with respect to two characteristic parameters of the system. It is shown that for certain values of these parameters, fold or Neimark-Sacker bifurcations occur, but codimension 2 (fold-Neimark-Sacker, double Neimark-Sacker and resonance 1:1) bifurcations may also be present. The direction and the stability of the Neimark-Sacker bifurcations are investigated by applying the center manifold theorem and the normal form theory
Relative Lyapunov Center Bifurcations
DEFF Research Database (Denmark)
Wulff, Claudia; Schilder, Frank
2014-01-01
Relative equilibria (REs) and relative periodic orbits (RPOs) are ubiquitous in symmetric Hamiltonian systems and occur, for example, in celestial mechanics, molecular dynamics, and rigid body motion. REs are equilibria, and RPOs are periodic orbits of the symmetry reduced system. Relative Lyapunov...... center bifurcations are bifurcations of RPOs from REs corresponding to Lyapunov center bifurcations of the symmetry reduced dynamics. In this paper we first prove a relative Lyapunov center theorem by combining recent results on the persistence of RPOs in Hamiltonian systems with a symmetric Lyapunov...... center theorem of Montaldi, Roberts, and Stewart. We then develop numerical methods for the detection of relative Lyapunov center bifurcations along branches of RPOs and for their computation. We apply our methods to Lagrangian REs of the N-body problem....
Rezaei Kivi, Araz; Azizi, Saber; Norouzi, Peyman
2017-12-01
In this paper, the nonlinear size-dependent static and dynamic behavior of an electrostatically actuated nano-beam is investigated. A fully clamped nano-beam is considered for the modeling of the deformable electrode of the NEMS. The governing differential equation of the motion is derived using Hamiltonian principle based on couple stress theory; a non-classical theory for considering length scale effects. The nonlinear partial differential equation of the motion is discretized to a nonlinear Duffing type ODE's using Galerkin method. Static and dynamic pull-in instabilities obtained by both classical theory and MCST are compared. At the second stage of analysis, shooting technique is utilized to obtain the frequency response curve, and to capture the periodic solutions of the motion; the stability of the periodic solutions are gained by Floquet theory. The nonlinear dynamic behavior of the deformable electrode due to the AC harmonic accompanied with size dependency is investigated.
Bifurcation dynamics of the tempered fractional Langevin equation
Energy Technology Data Exchange (ETDEWEB)
Zeng, Caibin, E-mail: macbzeng@scut.edu.cn; Yang, Qigui, E-mail: qgyang@scut.edu.cn [School of Mathematics, South China University of Technology, Guangzhou 510640 (China); Chen, YangQuan, E-mail: ychen53@ucmerced.edu [MESA LAB, School of Engineering, University of California, Merced, 5200 N. Lake Road, Merced, California 95343 (United States)
2016-08-15
Tempered fractional processes offer a useful extension for turbulence to include low frequencies. In this paper, we investigate the stochastic phenomenological bifurcation, or stochastic P-bifurcation, of the Langevin equation perturbed by tempered fractional Brownian motion. However, most standard tools from the well-studied framework of random dynamical systems cannot be applied to systems driven by non-Markovian noise, so it is desirable to construct possible approaches in a non-Markovian framework. We first derive the spectral density function of the considered system based on the generalized Parseval's formula and the Wiener-Khinchin theorem. Then we show that it enjoys interesting and diverse bifurcation phenomena exchanging between or among explosive-like, unimodal, and bimodal kurtosis. Therefore, our procedures in this paper are not merely comparable in scope to the existing theory of Markovian systems but also provide a possible approach to discern P-bifurcation dynamics in the non-Markovian settings.
Applying organizational behavior theory to primary care.
Mullangi, Samyukta; Saint, Sanjay
2017-03-01
Addressing the mounting primary care shortage in the United States has been a focus of educators and policy makers, especially with the passage of the Affordable Care Act in 2010 and the Medicare Access and CHIP Reauthorization Act in 2015, placing increased pressure on the system. The Association of American Medical Colleges recently projected a shortage of as many as 65,000 primary care physicians by 2025, in part because fewer than 20% of medical students are picking primary care for a career. We examined the issue of attracting medical students to primary care through the lens of organizational behavior theory. Assuming there are reasons other than lower income potential for why students are inclined against primary care, we applied various principles of the Herzberg 2-factor theory to reimagine the operational flow and design of primary care. We conclude by proposing several solutions to enrich the job, such as decreasing documentation requirements, reducing the emphasis on specialty consultations, and elevating physicians to a supervisory role.
Application of Bifurcation and Catastrophe Theories to Near Stall Flight Mechanics.
1985-01-01
subjective use of the theorem can be found in [32]. This has led to some considerable criticism of the theory itself as a result of its inability to give...Function, 4 (x,c) for CUBo ~s values of 02 with Cl=-3 Figure 4.3 brings the concepts discussed above together in a three dimensional diagram in the...points on the roll rate catastrophe map discussed in the next section. Figures 5.2 through 5.5 follow this page. 97 0 Arraft A (DR=Ot DE -.-5 deg*) S
Bifurcations sights, sounds, and mathematics
Matsumoto, Takashi; Kokubu, Hiroshi; Tokunaga, Ryuji
1993-01-01
Bifurcation originally meant "splitting into two parts. " Namely, a system under goes a bifurcation when there is a qualitative change in the behavior of the sys tem. Bifurcation in the context of dynamical systems, where the time evolution of systems are involved, has been the subject of research for many scientists and engineers for the past hundred years simply because bifurcations are interesting. A very good way of understanding bifurcations would be to see them first and study theories second. Another way would be to first comprehend the basic concepts and theories and then see what they look like. In any event, it is best to both observe experiments and understand the theories of bifurcations. This book attempts to provide a general audience with both avenues toward understanding bifurcations. Specifically, (1) A variety of concrete experimental results obtained from electronic circuits are given in Chapter 1. All the circuits are very simple, which is crucial in any experiment. The circuits, howev...
Wealth inhomogeneity applied to crash rate theory.
Shuler, Robert L
2015-11-01
A crash rate theory based on corporate economic utility maximization is applied to individual behavior in U.S. and German motorway death rates, by using wealth inhomogeneity data in ten-percentile bins to account for variations of utility maximization in the population. Germany and the U.S. have similar median wealth figures, a well-known indicator of accident risk, but different motorway death rates. It is found that inhomogeneity in roughly the 10(th) to 30(th) percentile, not revealed by popular measures such as the Gini index which focus on differences at the higher percentiles, provides a satisfactory explanation of the data. The inhomogeneity analysis reduces data disparity from a factor of 2.88 to 1.75 as compared with median wealth assumed homogeneity, and further to 1.09 with average wealth assumed homogeneity. The first reduction from 2.88 to 1.75 is attributable to inequality at lower percentiles and suggests it may be as important in indicating socioeconomic risk as extremes in the upper percentile ranges, and that therefore the U.S. socioeconomic risk may be higher than generally realized.
Applying Activity Theory in Multiagency Settings
Directory of Open Access Journals (Sweden)
Daniels H.,
2016-12-01
Full Text Available In this paper I explore the extent to which two approaches to the social formation of mind are compatible and may be used to enrich and extend each other. These are: Activity Theory (AT as derived from the work of the early Russian psychologists, Vygotsky and Leontiev, and the work of the sociologist Basil Bernstein. The purpose is to show how Bernstein provides a language of description which allows Vygotsky’s account of social formation of mind to be extended and enhanced through an understanding of the sociological processes which form specific modalities of pedagogic practice and their specialized scientific concepts. The two approaches engage with a common theme namely the social shaping of consciousness, from different perspectives and yet as Bernstein acknowledges both develop many of their core assumptions from the work of Marx and the French school of early twentieth century sociology. The work of the Russian linguist is also be used to further nuance the argument applied in multiagency settings.
Collet, Carlos; Onuma, Yoshinobu; Cavalcante, Rafael; Grundeken, Maik; Généreux, Philippe; Popma, Jeffrey; Costa, Ricardo; Stankovic, Goran; Tu, Shengxian; Reiber, Johan H C; Aben, Jean-Paul; Lassen, Jens Flensted; Louvard, Yves; Lansky, Alexandra; Serruys, Patrick W
2017-05-15
Bifurcation lesions represent one of the most challenging lesion subsets in interventional cardiology. The European Bifurcation Club (EBC) is an academic consortium whose goal has been to assess and recommend the appropriate strategies to manage bifurcation lesions. The quantitative coronary angiography (QCA) methods for the evaluation of bifurcation lesions have been subject to extensive research. Single-vessel QCA has been shown to be inaccurate for the assessment of bifurcation lesion dimensions. For this reason, dedicated bifurcation software has been developed and validated. These software packages apply the principles of fractal geometry to address the "step-down" in the bifurcation and to estimate vessel diameter accurately. This consensus update provides recommendations on the QCA analysis and reporting of bifurcation lesions based on the most recent scientific evidence from in vitro and in vivo studies and delineates future advances in the field of QCA dedicated bifurcation analysis.
Bifurcations and multistability in the extended Hindmarsh–Rose neuronal oscillator
International Nuclear Information System (INIS)
Megam Ngouonkadi, E.B.; Fotsin, H.B.; Louodop Fotso, P.; Kamdoum Tamba, V.; Cerdeira, Hilda A.
2016-01-01
Highlights: • We investigate the bifurcation and multistability in the extended Hindmarsh–Rose neuronal oscillator. • With the help of the normal form theory, we analyze the emergence and the direction of the Hopf bifurcation. • We also find that the extended Hindmarsh–Rose presents the multistability of oscillatory and silent regimes. • The results are helpful for enhancing our knowing on the way by which the neuronal system works, and encodes information. - Abstract: We report on the bifurcation analysis of an extended Hindmarsh–Rose (eHR) neuronal oscillator. We prove that Hopf bifurcation occurs in this system, when an appropriate chosen bifurcation parameter varies and reaches its critical value. Applying the normal form theory, we derive a formula to determine the direction of the Hopf bifurcation and the stability of bifurcating periodic flows. To observe this latter bifurcation and to illustrate its theoretical analysis, numerical simulations are performed. Hence, we present an explanation of the discontinuous behavior of the amplitude of the repetitive response as a function of system’s parameters based on the presence of the subcritical unstable oscillations. Furthermore, the bifurcation structures of the system are studied, with special care on the effects of parameters associated with the slow current and the slower dynamical process. We find that the system presents diversity of bifurcations such as period-doubling, symmetry breaking, crises and reverse period-doubling, when the afore mentioned parameters are varied in tiny steps. The complexity of the bifurcation structures seems useful to understand how neurons encode information or how they respond to external stimuli. Furthermore, we find that the extended Hindmarsh–Rose model also presents the multistability of oscillatory and silent regimes for precise sets of its parameters. This phenomenon plays a practical role in short-term memory and appears to give an evolutionary
Applied Hypergame Theory for Network Defense
2013-06-01
majority of game theory models are identified as either strategic , used to represent a simultaneous game, or extensive games, more often used to...the normal strategic form used in standard game theory analysis. The new model is referred to as Hypergame Normal Form (HNF), see Figure 2.7. The full...well with the selection of game theory attributes described. They provide a basic two-player, attacker and defender, game in strategic form with
Numerical bifurcation of Hamiltonian relative periodic orbits
DEFF Research Database (Denmark)
Wulff, Claudia; Schilder, Frank
2009-01-01
that the family of choreographies rotating around the $e^2$-axis bifurcates to the family of rotating choreographies that connects to the Lagrange relative equilibrium. Moreover, we compute several relative period-doubling bifurcations and a turning point of the family of planar rotating choreographies, which...... to symmetry-breaking/symmetry-increasing pitchfork bifurcations or to period-doubling/period-halving bifurcations. We apply our methods to the family of rotating choreographies which bifurcate from the famous figure eight solution of the three-body problem as angular momentum is varied. We find...
Motivational theory applied to hospital pharmacy practice.
Grace, M
1980-12-01
In recent years a great deal of attention has been paid to motivation and job satisfaction among hospital pharmacy practitioners. Institutional pharmacy managers should become more aware of ways in which they can motivate members of their staff. Specifically, Frederick Herzberg's Two-Factor Theory is discussed in reference to its origination, major tenets, and practical applications in institutional pharmacy practice settings. Principally, Herzberg's theory explains needs of workers in terms of extrinsic factors called "hygienes" and intrinsic factors called "motivators." The theory suggests that job satisfaction and dissatisfaction are not opposites but two separate dimensions. According to this theory, an employee will be motivated if the task allows for the following: 1)actual achievement, 2) recognition for achievement, 3) increased responsibility, 4) opportunity for growth (professionally), and 5) chance for advancement. It is concluded that some of these suggested applications can be useful to managers who are faced with low morale among the members of their staff.
Decision theory applied to radioactive repository construction
International Nuclear Information System (INIS)
Heilbron Filho, Paulo Fernando Lavalle; Pontedeiro, Elizabeth May
2001-01-01
The objective of this article is to present, through the presentation of an example, the applicability of the decision theory on the selection and construction of a repository for low and intermediate radioactive waste. (author)
Bifurcation analysis on a delayed SIS epidemic model with stage structure
Directory of Open Access Journals (Sweden)
Kejun Zhuang
2007-05-01
Full Text Available In this paper, a delayed SIS (Susceptible Infectious Susceptible model with stage structure is investigated. We study the Hopf bifurcations and stability of the model. Applying the normal form theory and the center manifold argument, we derive the explicit formulas determining the properties of the bifurcating periodic solutions. The conditions to guarantee the global existence of periodic solutions are established. Also some numerical simulations for supporting the theoretical are given.
Hopf bifurcation in love dynamical models with nonlinear couples and time delays
International Nuclear Information System (INIS)
Liao Xiaofeng; Ran Jiouhong
2007-01-01
A love dynamical models with nonlinear couples and two delays is considered. Local stability of this model is studied by analyzing the associated characteristic transcendental equation. We find that the Hopf bifurcation occurs when the sum of the two delays varies and passes a sequence of critical values. The stability and direction of the Hopf bifurcation are determined by applying the normal form theory and the center manifold theorem. Numerical example is given to illustrate our results
Stability and Hopf bifurcation for a delayed SLBRS computer virus model.
Zhang, Zizhen; Yang, Huizhong
2014-01-01
By incorporating the time delay due to the period that computers use antivirus software to clean the virus into the SLBRS model a delayed SLBRS computer virus model is proposed in this paper. The dynamical behaviors which include local stability and Hopf bifurcation are investigated by regarding the delay as bifurcating parameter. Specially, direction and stability of the Hopf bifurcation are derived by applying the normal form method and center manifold theory. Finally, an illustrative example is also presented to testify our analytical results.
Streamline topology: Patterns in fluid flows and their bifurcations
DEFF Research Database (Denmark)
Brøns, Morten
2007-01-01
Using dynamical systems theory, we consider structures such as vortices and separation in the streamline patterns of fluid flows. Bifurcation of patterns under variation of external parameters is studied using simplifying normal form transformations. Flows away from boundaries, flows close to fix...... walls, and axisymmetric flows are analyzed in detail. We show how to apply the ideas from the theory to analyze numerical simulations of the vortex breakdown in a closed cylindrical container....
Applying Adapted Big Five Teamwork Theory to Agile Software Development
Strode, Diane
2016-01-01
Teamwork is a central tenet of agile software development and various teamwork theories partially explain teamwork in that context. Big Five teamwork theory is one of the most influential teamwork theories, but prior research shows that the team leadership concept in this theory it is not applicable to agile software development. This paper applies an adapted form of Big Five teamwork theory to cases of agile software development. Three independent cases were drawn from a single organisation....
History and theory in "applied ethics".
Beauchamp, Tom L
2007-03-01
Robert Baker and Laurence McCullough argue that the "applied ethics model" is deficient and in need of a replacement model. However, they supply no clear meaning to "applied ethics" and miss most of what is important in the literature on methodology that treats this question. The Baker-McCullough account of medical and applied ethics is a straw man that has had no influence in these fields or in philosophical ethics. The authors are also on shaky historical grounds in dealing with two problems: (1) the historical source of the notion of "practical ethics" and (2) the historical source of and the assimilation of the term "autonomy" into applied philosophy and professional ethics. They mistakenly hold (1) that the expression "practical ethics" was first used in a publication by Thomas Percival and (2) that Kant is the primary historical source of the notion of autonomy as that notion is used in contemporary applied ethics.
Learning Theory Applied to the Biology Classroom.
Novak, Joseph D.
1980-01-01
The material presented in this article is intended to help students learn how to learn. The seven key concepts of David Ausubel's assimilation theory for cognitive learning are discussed with reference to the classroom. Concept mapping is suggested as a tool for demonstrating how the seven key concepts function. (SA)
Dynamic bifurcations on financial markets
International Nuclear Information System (INIS)
Kozłowska, M.; Denys, M.; Wiliński, M.; Link, G.; Gubiec, T.; Werner, T.R.; Kutner, R.; Struzik, Z.R.
2016-01-01
We provide evidence that catastrophic bifurcation breakdowns or transitions, preceded by early warning signs such as flickering phenomena, are present on notoriously unpredictable financial markets. For this we construct robust indicators of catastrophic dynamical slowing down and apply these to identify hallmarks of dynamical catastrophic bifurcation transitions. This is done using daily closing index records for the representative examples of financial markets of small and mid to large capitalisations experiencing a speculative bubble induced by the worldwide financial crisis of 2007-08.
Applied optimal control theory of distributed systems
Lurie, K A
1993-01-01
This book represents an extended and substantially revised version of my earlierbook, Optimal Control in Problems ofMathematical Physics,originally published in Russian in 1975. About 60% of the text has been completely revised and major additions have been included which have produced a practically new text. My aim was to modernize the presentation but also to preserve the original results, some of which are little known to a Western reader. The idea of composites, which is the core of the modern theory of optimization, was initiated in the early seventies. The reader will find here its implementation in the problem of optimal conductivity distribution in an MHD-generatorchannel flow.Sincethen it has emergedinto an extensive theory which is undergoing a continuous development. The book does not pretend to be a textbook, neither does it offer a systematic presentation of the theory. Rather, it reflects a concept which I consider as fundamental in the modern approach to optimization of dis tributed systems. ...
Electric circuit theory applied electricity and electronics
Yorke, R
1981-01-01
Electric Circuit Theory provides a concise coverage of the framework of electrical engineering. Comprised of six chapters, this book emphasizes the physical process of electrical engineering rather than abstract mathematics. Chapter 1 deals with files, circuits, and parameters, while Chapter 2 covers the natural and forced response of simple circuit. Chapter 3 talks about the sinusoidal steady state, and Chapter 4 discusses the circuit analysis. The fifth chapter tackles frequency response of networks, and the last chapter covers polyphase systems. This book will be of great help to electrical
Gassmann Theory Applies to Nanoporous Media
Gor, Gennady Y.; Gurevich, Boris
2018-01-01
Recent progress in extraction of unconventional hydrocarbon resources has ignited the interest in the studies of nanoporous media. Since many thermodynamic and mechanical properties of nanoscale solids and fluids differ from the analogous bulk materials, it is not obvious whether wave propagation in nanoporous media can be described using the same framework as in macroporous media. Here we test the validity of Gassmann equation using two published sets of ultrasonic measurements for a model nanoporous medium, Vycor glass, saturated with two different fluids, argon, and n-hexane. Predictions of the Gassmann theory depend on the bulk and shear moduli of the dry samples, which are known from ultrasonic measurements and the bulk moduli of the solid and fluid constituents. The solid bulk modulus can be estimated from adsorption-induced deformation or from elastic effective medium theory. The fluid modulus can be calculated according to the Tait-Murnaghan equation at the solvation pressure in the pore. Substitution of these parameters into the Gassmann equation provides predictions consistent with measured data. Our findings set up a theoretical framework for investigation of fluid-saturated nanoporous media using ultrasonic elastic wave propagation.
Linear response theory applied to geoengineering
Bodai, Tamas; Lucarini, Valerio
2017-04-01
We investigate in an intermediate-complexity climate model the applicability of linear response theory to a geoengineering problem. Global climate change with respect to an appropriate ensemble average of the surface air temperature ⟨[T]⟩ due to a given rise in carbon dioxide concentration [CO2] is attempted to be canceled out or modulated by an appropriately chosen modulation of the solar forcing. The latter is predicted by linear response theory in frequency-domain as: Δfs(ω) = (Δ⟨[T]⟩(ω) -χCO2(ω)ΔfCO2(ω))/χs(ω), where the χ's are linear susceptibilities. With a doubling of [CO2] the response is nonlinear to a certain degree, but a significant cancellation with respect to (wrt.) [T] is achieved, the asymptotic total response to combined forcing being only 10% of that with [CO2]-doubling alone. We investigate in this geoengineering scenario the response wrt. zonal or regional averages of T too. The nonlinearities have a more severe effect with respect to the predictability of the spatial total response pattern, but in actual fact a significant cancellation is achieved even locally. Similar conclusions can be drawn wrt. the model variable of large scale precipitation. The regional and global response can be characterized by a single dominant multi-year time scale. The spatial pattern of the response time is rather nontrivial.
International Nuclear Information System (INIS)
Song Yongli; Tadé, Moses O; Zhang Tonghua
2009-01-01
In this paper, a delayed neural network with unidirectional coupling is considered which consists of two two-dimensional nonlinear differential equation systems with exponential decay where one system receives a delayed input from the other system. Some parameter regions are given for conditional/absolute stability and Hopf bifurcations by using the theory of functional differential equations. Conditions ensuring the stability and direction of the Hopf bifurcation are determined by applying the normal form theory and the centre manifold theorem. We also investigate the spatio-temporal patterns of bifurcating periodic oscillations by using the symmetric bifurcation theory of delay-differential equations combined with representation theory of Lie groups. Then the global continuation of phase-locked periodic solutions is investigated. Numerical simulations are given to illustrate the results obtained
Coasting beam theory applied to bunches
International Nuclear Information System (INIS)
Hereward, H.
1975-01-01
It is plausible to apply coasting beam criteria to bunches if one has short wavelength disturbances of the bunch and short memory wake fields, where short means short compared with a bunch length, for then one can argue that a piece of the bunch near the middle does not even know that the bunch has ends. Some other conditions probably required to validate this approach are discussed. The local Keil-Schnell criterion is derived from the local dispersion integral
Nodal aberration theory applied to freeform surfaces
Fuerschbach, Kyle; Rolland, Jannick P.; Thompson, Kevin P.
2014-12-01
When new three-dimensional packages are developed for imaging optical systems, the rotational symmetry of the optical system is often broken, changing its imaging behavior and making the optical performance worse. A method to restore the performance is to use freeform optical surfaces that compensate directly the aberrations introduced from tilting and decentering the optical surfaces. In order to effectively optimize the shape of a freeform surface to restore optical functionality, it is helpful to understand the aberration effect the surface may induce. Using nodal aberration theory the aberration fields induced by a freeform surface in an optical system are explored. These theoretical predications are experimentally validated with the design and implementation of an aberration generating telescope.
Stability and bifurcation in a simplified four-neuron BAM neural network with multiple delays
Directory of Open Access Journals (Sweden)
2006-01-01
Full Text Available We first study the distribution of the zeros of a fourth-degree exponential polynomial. Then we apply the obtained results to a simplified bidirectional associated memory (BAM neural network with four neurons and multiple time delays. By taking the sum of the delays as the bifurcation parameter, it is shown that under certain assumptions the steady state is absolutely stable. Under another set of conditions, there are some critical values of the delay, when the delay crosses these critical values, the Hopf bifurcation occurs. Furthermore, some explicit formulae determining the stability and the direction of periodic solutions bifurcating from Hopf bifurcations are obtained by applying the normal form theory and center manifold reduction. Numerical simulations supporting the theoretical analysis are also included.
Mirror theory applied to toroidal systems
International Nuclear Information System (INIS)
Cohen, R.H.
1987-01-01
Central features of a mirror plasma are strong departures from Maxwellian distribution functions, ambipolar potentials and densities which vary along a field line, end losses, and the mirror field itself. To examine these features, mirror theorists have developed analytical and numerical techniques to solve the Fokker-Planck equation, evaluate the potentials consistent with the resulting distribution functions, and assess the microstability of these distributions. Various combinations of mirror-plasma features are present and important in toroidal plasmas as well, particularly in the edge region and in plasmas with strong rf heating. In this paper we survey problems in toroidal plasmas where mirror theory and computational techniques are applicable, and discuss in more detail three specific examples: calculation of the toroidal generalization of the Spitzer-Haerm distribution function (from which trapped-particle effects on current drive can be calculated), evaluation of the nonuniform potential and density set up by pulsed electron-cyclotron heating, and calculation of steady-state distribution functions in the presence of strong rf heating and collisions. 37 refs
Applying complexity theory: a review to inform evaluation design.
Walton, Mat
2014-08-01
Complexity theory has increasingly been discussed and applied within evaluation literature over the past decade. This article reviews the discussion and use of complexity theory within academic journal literature. The aim is to identify the issues to be considered when applying complexity theory to evaluation. Reviewing 46 articles, two groups of themes are identified. The first group considers implications of applying complexity theory concepts for defining evaluation purpose, scope and units of analysis. The second group of themes consider methodology and method. Results provide a starting point for a configuration of an evaluation approach consistent with complexity theory, whilst also identifying a number of design considerations to be resolved within evaluation planning. Copyright © 2014 Elsevier Ltd. All rights reserved.
Symmetric/asymmetric bifurcation behaviours of a bogie system
DEFF Research Database (Denmark)
Xue-jun, Gao; Ying-hui, Li; Yuan, Yue
2013-01-01
Based on the bifurcation and stability theory of dynamical systems, the symmetric/asymmetric bifurcation behaviours and chaotic motions of a railway bogie system under a complex nonlinear wheel–rail contact relation are investigated in detail by the ‘resultant bifurcation diagram’ method with slo...
The diversity and beauty of applied operator theory
Potts, Daniel; Stollmann, Peter; Wenzel, David
2018-01-01
This book presents 29 invited articles written by participants of the International Workshop on Operator Theory and its Applications held in Chemnitz in 2017. The contributions include both expository essays and original research papers illustrating the diversity and beauty of insights gained by applying operator theory to concrete problems. The topics range from control theory, frame theory, Toeplitz and singular integral operators, Schrödinger, Dirac, and Kortweg-de Vries operators, Fourier integral operator zeta-functions, C*-algebras and Hilbert C*-modules to questions from harmonic analysis, Monte Carlo integration, Fibonacci Hamiltonians, and many more. The book offers researchers in operator theory open problems from applications that might stimulate their work and shows those from various applied fields, such as physics, engineering, or numerical mathematics how to use the potential of operator theory to tackle interesting practical problems.
Linear Control Theory as Applied to Smart Structures
National Research Council Canada - National Science Library
Kantor, George A
1995-01-01
This thesis investigates linear control theory as applied to smart structures. Specifically, the problem of active vibration damping in a flexible cantilever beam using piezo-electric ceramic crystals (PZT...
Applying Social Capital Theory and the Technology Acceptance ...
African Journals Online (AJOL)
Applying Social Capital Theory and the Technology Acceptance Model in information and knowledge sharing research. ... Inkanyiso: Journal of Humanities and Social Sciences ... The paper explains the components, relevance and practical applicability of the two theories to information and knowledge sharing research.
Some Consequences of Learning Theory Applied to Division of Fractions
Bidwell, James K.
1971-01-01
Reviews the learning theories of Robert Gagne and David Ausubel, and applies these theories to the three most common approaches to teaching division of fractions: common denominator, complex fraction, and inverse operation methods. Such analysis indicates the inverse approach should be most effective for meaningful teaching, as is verified by…
Social Justice and Lesbian Feminism: Two Theories Applied to Homophobia
Directory of Open Access Journals (Sweden)
Denise L. Levy
2007-12-01
Full Text Available Trends in contemporary social work include the use of an eclectic theory base. In an effort to incorporate multiple theories, this article will examine the social problem of homophobia using two different theoretical perspectives: John Rawls’ theory of social justice and lesbian feminist theory.Homophobia, a current social problem, can be defined as “dislike or hatred toward homosexuals, including both cultural and personal biases against homosexuals” (Sullivan, 2003, p. 2. Rawls’ theory of justice and lesbian feminist theory are especially relevant to the issue of homophobia and provide a useful lens to understanding this social problem. In this article, these two theories will be summarized, applied to the issue of homophobia, and compared and contrasted based on their utility.
Hopf bifurcation in a environmental defensive expenditures model with time delay
International Nuclear Information System (INIS)
Russu, Paolo
2009-01-01
In this paper a three-dimensional environmental defensive expenditures model with delay is considered. The model is based on the interactions among visitors V, quality of ecosystem goods E, and capital K, intended as accommodation and entertainment facilities, in Protected Areas (PAs). The tourism user fees (TUFs) are used partly as a defensive expenditure and partly to increase the capital stock. The stability and existence of Hopf bifurcation are investigated. It is that stability switches and Hopf bifurcation occurs when the delay t passes through a sequence of critical values, τ 0 . It has been that the introduction of a delay is a destabilizing process, in the sense that increasing the delay could cause the bio-economics to fluctuate. Formulas about the stability of bifurcating periodic solution and the direction of Hopf bifurcation are exhibited by applying the normal form theory and the center manifold theorem. Numerical simulations are given to illustrate the results.
Stability and Hopf Bifurcation in a Computer Virus Model with Multistate Antivirus
Directory of Open Access Journals (Sweden)
Tao Dong
2012-01-01
Full Text Available By considering that people may immunize their computers with countermeasures in susceptible state, exposed state and using anti-virus software may take a period of time, a computer virus model with time delay based on an SEIR model is proposed. We regard time delay as bifurcating parameter to study the dynamical behaviors which include local asymptotical stability and local Hopf bifurcation. By analyzing the associated characteristic equation, Hopf bifurcation occurs when time delay passes through a sequence of critical value. The linerized model and stability of the bifurcating periodic solutions are also derived by applying the normal form theory and the center manifold theorem. Finally, an illustrative example is also given to support the theoretical results.
Theories and Modules Applied in Islamic Counseling Practices in Malaysia.
Zakaria, Norazlina; Mat Akhir, Noor Shakirah
2017-04-01
Some Malaysian scholars believe that the theoretical basis and models of intervention in Islamic counseling practices in Malaysia are deficient and not eminently identified. This study investigated and describes the nature of current Islamic counseling practices including the theories and modules of Islamic counseling that are been practiced in Malaysia. This qualitative research has employed data that mainly consist of texts gathered from literatures and semi-structured interviews of 18 informants. It employed grounded theory analysis, and the result shows that most of the practitioners had applied integrated conventional counseling theories with Islamic rituals, references, interventions and ethics. Some had also applied Islamic theories and modules formulated in Malaysia such as iCBT, al-Ghazali counseling theories, Cognitive ad-Deen, KBJ, Prophetic Counseling and Asma Allah al-Husna Counseling Therapy.
Bifurcation in autonomous and nonautonomous differential equations with discontinuities
Akhmet, Marat
2017-01-01
This book is devoted to bifurcation theory for autonomous and nonautonomous differential equations with discontinuities of different types. That is, those with jumps present either in the right-hand-side or in trajectories or in the arguments of solutions of equations. The results obtained in this book can be applied to various fields such as neural networks, brain dynamics, mechanical systems, weather phenomena, population dynamics, etc. Without any doubt, bifurcation theory should be further developed to different types of differential equations. In this sense, the present book will be a leading one in this field. The reader will benefit from the recent results of the theory and will learn in the very concrete way how to apply this theory to differential equations with various types of discontinuity. Moreover, the reader will learn new ways to analyze nonautonomous bifurcation scenarios in these equations. The book will be of a big interest both for beginners and experts in the field. For the former group o...
Bifurcations of non-smooth systems
Angulo, Fabiola; Olivar, Gerard; Osorio, Gustavo A.; Escobar, Carlos M.; Ferreira, Jocirei D.; Redondo, Johan M.
2012-12-01
Non-smooth systems (namely piecewise-smooth systems) have received much attention in the last decade. Many contributions in this area show that theory and applications (to electronic circuits, mechanical systems, …) are relevant to problems in science and engineering. Specially, new bifurcations have been reported in the literature, and this was the topic of this minisymposium. Thus both bifurcation theory and its applications were included. Several contributions from different fields show that non-smooth bifurcations are a hot topic in research. Thus in this paper the reader can find contributions from electronics, energy markets and population dynamics. Also, a carefully-written specific algebraic software tool is presented.
Bifurcation analysis of 3D ocean flows using a parallel fully-implicit ocean model
Thies, Jonas; Wubs, Fred; Dijkstra, Henk A.
2009-01-01
To understand the physics and dynamics of the ocean circulation, techniques of numerical bifurcation theory such as continuation methods have proved to be useful. Up to now these techniques have been applied to models with relatively few (O(10(5))) degrees of freedom such as multi-layer
Bifurcation analysis of 3D ocean flows using a parallel fully-implicit ocean model
Thies, J.; Wubs, F.W.; Dijkstra, H.A.
2009-01-01
To understand the physics and dynamics of the ocean circulation, techniques of numerical bifurcation theory such as continuation methods have proved to be useful. Up to now these techniques have been applied to models with relatively few degrees of freedom such as multi-layer quasi-geostrophic and
Theorizing the Self: Digital Storytelling, Applying Theory, and Multimodal Learning
Kortegast, Carrie; Davis, Jonathan
2017-01-01
This article discusses the use of digital storytelling, a pedagogical tool, to enhance student learning and meaning-making. During the process of creating and sharing their digital stories, students engaged in self-reflexivity and demonstrated the ability to apply theories of student development to their personal experiences. Findings have…
Regularization of the Boundary-Saddle-Node Bifurcation
Directory of Open Access Journals (Sweden)
Xia Liu
2018-01-01
Full Text Available In this paper we treat a particular class of planar Filippov systems which consist of two smooth systems that are separated by a discontinuity boundary. In such systems one vector field undergoes a saddle-node bifurcation while the other vector field is transversal to the boundary. The boundary-saddle-node (BSN bifurcation occurs at a critical value when the saddle-node point is located on the discontinuity boundary. We derive a local topological normal form for the BSN bifurcation and study its local dynamics by applying the classical Filippov’s convex method and a novel regularization approach. In fact, by the regularization approach a given Filippov system is approximated by a piecewise-smooth continuous system. Moreover, the regularization process produces a singular perturbation problem where the original discontinuous set becomes a center manifold. Thus, the regularization enables us to make use of the established theories for continuous systems and slow-fast systems to study the local behavior around the BSN bifurcation.
Bifurcating optical pattern recognition in photorefractive crystals
Liu, Hua-Kuang
1993-01-01
A concept of bifurcating optical pattern rocognizer (BIOPAR) is described and demonstrated experimentally, using barium titanate crystal. When an input is applied to BIOPAR, the output may be directed to two ports.
Non-autonomous bifurcation in impulsive systems
Directory of Open Access Journals (Sweden)
Marat Akhmet
2013-12-01
Full Text Available This is the first paper which considers non-autonomous bifurcations in impulsive differential equations. Impulsive generalizations of the non-autonomous pitchfork and transcritical bifurcation are discussed. We consider scalar differential equation with fixed moments of impulses. It is illustrated by means of certain systems how the idea of pullback attracting sets remains a fruitful concept in the impulsive systems. Basics of the theory are provided.
Applying the Causal Theory of Reference to Intentional Concepts
DEFF Research Database (Denmark)
Michael, John Andrew; Macleod, Miles
2013-01-01
. Specifically, we argue that some phenomena in early social de- velopment ðe.g., mimicry, gaze following, and emotional contagionÞ can serve as refer- ence fixers that enable children to track others’ intentional states and, thus, to refer to those states. This allows intentional concepts to be anchored......We argue that many recent philosophical discussions about the reference of everyday concepts of intentional states have implicitly been predicated on descriptive theories of reference. To rectify this, we attempt to demonstrate how a causal theory can be applied to intentional concepts...... to their referents, even if folk psy- chological descriptions turn out to be false....
Spectral analysis and filter theory in applied geophysics
Buttkus, Burkhard
2000-01-01
This book is intended to be an introduction to the fundamentals and methods of spectral analysis and filter theory and their appli cations in geophysics. The principles and theoretical basis of the various methods are described, their efficiency and effectiveness eval uated, and instructions provided for their practical application. Be sides the conventional methods, newer methods arediscussed, such as the spectral analysis ofrandom processes by fitting models to the ob served data, maximum-entropy spectral analysis and maximum-like lihood spectral analysis, the Wiener and Kalman filtering methods, homomorphic deconvolution, and adaptive methods for nonstation ary processes. Multidimensional spectral analysis and filtering, as well as multichannel filters, are given extensive treatment. The book provides a survey of the state-of-the-art of spectral analysis and fil ter theory. The importance and possibilities ofspectral analysis and filter theory in geophysics for data acquisition, processing an...
Superconductivity theory applied to the periodic table of the elements
Elifritz, Thomas Lee
1995-01-01
The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition is applied to the periodic table of the elements, in order to isolate the essential features of of high temperature superconductivity and to predict its occurrence with the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity.
Superconductivity theory applied to the periodic table of the elements
International Nuclear Information System (INIS)
Elifritz, T.L.
1994-01-01
The modern theory of superconductivity, based upon the BCS to Bose-Einstein transition, is applied to the periodic table of the elements, in order to isolate the essential features of high temperature superconductivity and to predict its occurrence within the periodic table. It is predicted that Sodium-Ammonia, Sodium Zinc Phosphide and Bismuth (I) Iodide are promising materials for experimental explorations of high temperature superconductivity
Applying the Theory of Contraints to Supply Chain Management
Simatupang, Togar Mangihut; Sandroto, Indah Victoria
2004-01-01
Supply chain management among independent firms often provide larger benefits form effectively satisfying customer needs and wants than working in isolation. However, many improvement initiatives often end up with devastating effects on supply chain performance. Part of the reason is sub-optimisation among the chain members resulting form a lack of awareness about the importance of the perspective of the supply chain as a whole and the existence of constraint(s). This paper applies the Theory...
International Nuclear Information System (INIS)
Kaslik, E.; Balint, St.
2009-01-01
In this paper, a bifurcation analysis is undertaken for a discrete-time Hopfield neural network of two neurons with two different delays and self-connections. Conditions ensuring the asymptotic stability of the null solution are found, with respect to two characteristic parameters of the system. It is shown that for certain values of these parameters, Fold or Neimark-Sacker bifurcations occur, but Flip and codimension 2 (Fold-Neimark-Sacker, double Neimark-Sacker, resonance 1:1 and Flip-Neimark-Sacker) bifurcations may also be present. The direction and the stability of the Neimark-Sacker bifurcations are investigated by applying the center manifold theorem and the normal form theory
Streamline Patterns and their Bifurcations near a wall with Navier slip Boundary Conditions
DEFF Research Database (Denmark)
Tophøj, Laust; Møller, Søren; Brøns, Morten
2006-01-01
We consider the two-dimensional topology of streamlines near a surface where the Navier slip boundary condition applies. Using transformations to bring the streamfunction in a simple normal form, we obtain bifurcation diagrams of streamline patterns under variation of one or two external parameters....... Topologically, these are identical with the ones previously found for no-slip surfaces. We use the theory to analyze the Stokes flow inside a circle, and show how it can be used to predict new bifurcation phenomena. ©2006 American Institute of Physics...
Turing instability and bifurcation analysis in a diffusive bimolecular system with delayed feedback
Wei, Xin; Wei, Junjie
2017-09-01
A diffusive autocatalytic bimolecular model with delayed feedback subject to Neumann boundary conditions is considered. We mainly study the stability of the unique positive equilibrium and the existence of periodic solutions. Our study shows that diffusion can give rise to Turing instability, and the time delay can affect the stability of the positive equilibrium and result in the occurrence of Hopf bifurcations. By applying the normal form theory and center manifold reduction for partial functional differential equations, we investigate the stability and direction of the bifurcations. Finally, we give some simulations to illustrate our theoretical results.
Bifurcation and instability problems in vortex wakes
DEFF Research Database (Denmark)
Aref, Hassan; Brøns, Morten; Stremler, Mark A.
2007-01-01
A number of instability and bifurcation problems related to the dynamics of vortex wake flows are addressed using various analytical tools and approaches. We discuss the bifurcations of the streamline pattern behind a bluff body as a vortex wake is produced, a theory of the universal Strouhal......-Reynolds number relation for vortex wakes, the bifurcation diagram for "exotic" wake patterns behind an oscillating cylinder first determined experimentally by Williamson & Roshko, and the bifurcations in topology of the streamlines pattern in point vortex streets. The Hamiltonian dynamics of point vortices...... in a periodic strip is considered. The classical results of von Kármán concerning the structure of the vortex street follow from the two-vortices-in-a-strip problem, while the stability results follow largely from a four-vortices-in-a-strip analysis. The three-vortices-in-a-strip problem is argued...
Systems biology: the reincarnation of systems theory applied in biology?
Wolkenhauer, O
2001-09-01
With the availability of quantitative data on the transcriptome and proteome level, there is an increasing interest in formal mathematical models of gene expression and regulation. International conferences, research institutes and research groups concerned with systems biology have appeared in recent years and systems theory, the study of organisation and behaviour per se, is indeed a natural conceptual framework for such a task. This is, however, not the first time that systems theory has been applied in modelling cellular processes. Notably in the 1960s systems theory and biology enjoyed considerable interest among eminent scientists, mathematicians and engineers. Why did these early attempts vanish from research agendas? Here we shall review the domain of systems theory, its application to biology and the lessons that can be learned from the work of Robert Rosen. Rosen emerged from the early developments in the 1960s as a main critic but also developed a new alternative perspective to living systems, a concept that deserves a fresh look in the post-genome era of bioinformatics.
Stability and bifurcation analysis in a delayed SIR model
International Nuclear Information System (INIS)
Jiang Zhichao; Wei Junjie
2008-01-01
In this paper, a time-delayed SIR model with a nonlinear incidence rate is considered. The existence of Hopf bifurcations at the endemic equilibrium is established by analyzing the distribution of the characteristic values. A explicit algorithm for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions are derived by using the normal form and the center manifold theory. Numerical simulations to support the analytical conclusions are carried out
Nonlinear physical systems spectral analysis, stability and bifurcations
Kirillov, Oleg N
2013-01-01
Bringing together 18 chapters written by leading experts in dynamical systems, operator theory, partial differential equations, and solid and fluid mechanics, this book presents state-of-the-art approaches to a wide spectrum of new and challenging stability problems.Nonlinear Physical Systems: Spectral Analysis, Stability and Bifurcations focuses on problems of spectral analysis, stability and bifurcations arising in the nonlinear partial differential equations of modern physics. Bifurcations and stability of solitary waves, geometrical optics stability analysis in hydro- and magnetohydrodynam
Modeling in applied sciences a kinetic theory approach
Pulvirenti, Mario
2000-01-01
Modeling complex biological, chemical, and physical systems, in the context of spatially heterogeneous mediums, is a challenging task for scientists and engineers using traditional methods of analysis Modeling in Applied Sciences is a comprehensive survey of modeling large systems using kinetic equations, and in particular the Boltzmann equation and its generalizations An interdisciplinary group of leading authorities carefully develop the foundations of kinetic models and discuss the connections and interactions between model theories, qualitative and computational analysis and real-world applications This book provides a thoroughly accessible and lucid overview of the different aspects, models, computations, and methodology for the kinetic-theory modeling process Topics and Features * Integrated modeling perspective utilized in all chapters * Fluid dynamics of reacting gases * Self-contained introduction to kinetic models * Becker–Doring equations * Nonlinear kinetic models with chemical reactions * Kinet...
Applying strategic management theories in public sector organizations
DEFF Research Database (Denmark)
Hansen, Jesper Rosenberg; Ewan, Ferlie
2016-01-01
This article discusses the utility of two different strategic management theories in different types of public organizations including contemporary New Public Management-based public organizations, namely Porter's strategic positioning model and the resource-based view of strategy. We argue...... conditions: the degree of administrative autonomy, performance-based budgeting and market-like competition. We give empirical examples drawn from public servives in the UK and Denmark. We call for more exploration of these (and other) strategic management approaches within contemporary public services...... that possibiliteis for applying these theories vary depending on the type of public organizations involved, and are les appropriate in traditional settings but more relevant in autonomized and market-like service-delivery organizations. We further propose that their increased applicability depends on three specific...
Applied evolutionary theories for engineering of secondary metabolic pathways.
Bachmann, Brian O
2016-12-01
An expanded definition of 'secondary metabolism' is emerging. Once the exclusive provenance of naturally occurring organisms, evolved over geological time scales, secondary metabolism increasingly encompasses molecules generated via human engineered biocatalysts and biosynthetic pathways. Many of the tools and strategies for enzyme and pathway engineering can find origins in evolutionary theories. This perspective presents an overview of selected proposed evolutionary strategies in the context of engineering secondary metabolism. In addition to the wealth of biocatalysts provided via secondary metabolic pathways, improving the understanding of biosynthetic pathway evolution will provide rich resources for methods to adapt to applied laboratory evolution. Copyright © 2016 Elsevier Ltd. All rights reserved.
Action learning in virtual higher education: applying leadership theory.
Curtin, Joseph
2016-05-03
This paper reports the historical foundation of Northeastern University's course, LDR 6100: Developing Your Leadership Capability, a partial literature review of action learning (AL) and virtual action learning (VAL), a course methodology of LDR 6100 requiring students to apply leadership perspectives using VAL as instructed by the author, questionnaire and survey results of students who evaluated the effectiveness of their application of leadership theories using VAL and insights believed to have been gained by the author administering VAL. Findings indicate most students thought applying leadership perspectives using AL was better than considering leadership perspectives not using AL. In addition as implemented in LDR 6100, more students evaluated VAL positively than did those who assessed VAL negatively.
Gap Dependent Bifurcation Behavior of a Nano-Beam Subjected to a Nonlinear Electrostatic Pressure
Directory of Open Access Journals (Sweden)
Mohammad Fathalilou
Full Text Available This paper presents a study on the gap dependent bifurcation behavior of an electro statically-actuated nano-beam. The sizedependent behavior of the beam was taken into account by applying the couple stress theory. Two small and large gap distance regimes have been considered in which the intermolecular vdW and Casimir forces are dominant, respectively. It has been shown that changing the gap size can affect the fundamental frequency of the beam. The bifurcation diagrams for small gap distance revealed that by changing the gap size, the number and type of the fixed points can change. However, for large gap regime, where the Casimir force is the dominant intermolecular force, changing the gap size does not affect the quality of the bifurcation behavior.
Nemeth, Michael P.
2010-01-01
A comprehensive development of nondimensional parameters and equations for nonlinear and bifurcations analyses of quasi-shallow shells, based on the Donnell-Mushtari-Vlasov theory for thin anisotropic shells, is presented. A complete set of field equations for geometrically imperfect shells is presented in terms general of lines-of-curvature coordinates. A systematic nondimensionalization of these equations is developed, several new nondimensional parameters are defined, and a comprehensive stress-function formulation is presented that includes variational principles for equilibrium and compatibility. Bifurcation analysis is applied to the nondimensional nonlinear field equations and a comprehensive set of bifurcation equations are presented. An extensive collection of tables and figures are presented that show the effects of lamina material properties and stacking sequence on the nondimensional parameters.
Directory of Open Access Journals (Sweden)
Zhong Zhao
2014-01-01
to the stability of the boundary periodic solution. By use of standard techniques of bifurcation theory, the periodic oscillations in substrate, plasmid-bearing, and plasmid-free organisms are shown when some conditions are satisfied. Our results can be applied to control bioreactor aimed at producing commercial producers through genetically altered organisms.
Applying Diffusion of Innovation Theory to Intervention Development.
Dearing, James W
2009-09-01
Few social science theories have a history of conceptual and empirical study as long as does the diffusion of innovations. The robustness of this theory derives from the many disciplines and fields of study in which diffusion has been studied, from the international richness of these studies, and from the variety of new ideas, practices, programs, and technologies that have been the objects of diffusion research. Early theorizing from the beginning of the 20th century was gradually displaced by post hoc empirical research that described and explained diffusion processes. By the 1950s, diffusion researchers had begun to apply the collective knowledge learned about naturalistic diffusion in tests of process interventions to affect the spread of innovations. Now, this purposive objective has given form to a science of dissemination in which evidence-based practices are designed a priori not just to result in internal validity but to increase the likelihood that external validity and diffusion both are more likely to result. Here, I review diffusion theory and focus on seven concepts-intervention attributes, intervention clusters, demonstration projects, societal sectors, reinforcing contextual conditions, opinion leadership, and intervention adaptation-with potential for accelerating the spread of evidence-based practices, programs, and policies in the field of social work.
Comments on the Bifurcation Structure of 1D Maps
DEFF Research Database (Denmark)
Belykh, V.N.; Mosekilde, Erik
1997-01-01
The paper presents a complementary view on some of the phenomena related to the bifurcation structure of unimodal maps. An approximate renormalization theory for the period-doubling cascade is developed, and a mapping procedure is established that accounts directly for the box-within-a-box struct......The paper presents a complementary view on some of the phenomena related to the bifurcation structure of unimodal maps. An approximate renormalization theory for the period-doubling cascade is developed, and a mapping procedure is established that accounts directly for the box......-within-a-box structure of the total bifurcation set. This presents a picture in which the homoclinic orbit bifurcations act as a skeleton for the bifurcational set. At the same time, experimental results on continued subharmonic generation for piezoelectrically amplified sound waves, predating the Feigenbaum theory...
Directory of Open Access Journals (Sweden)
Jeffrey S. Harrison
2015-09-01
Full Text Available Objective – This article provides a brief overview of stakeholder theory, clears up some widely held misconceptions, explains the importance of examining stakeholder theory from a variety of international perspectives and how this type of research will advance management theory, and introduces the other articles in the special issue. Design/methodology/approach – Some of the foundational ideas of stakeholder theory are discussed, leading to arguments about the importance of the theory to management research, especially in an international context. Findings – Stakeholder theory is found to be a particularly useful perspective for addressing some of the important issues in business from an international perspective. It offers an opportunity to reinterpret a variety of concepts, models and phenomena across may different disciplines. Practical implications – The concepts explored in this article may be applied in many contexts, domestically and internationally, and across business disciplines as diverse as economics, public administration, finance, philosophy, marketing, law, and management. Originality/value – Research on stakeholder theory in an international context is both lacking and sorely needed. This article and the others in this special issue aim to help fill that void.
Views on the Hopf bifurcation with respect to voltage instabilities
Energy Technology Data Exchange (ETDEWEB)
Roa-Sepulveda, C.A. [Universidad de Concepcion, Concepcion (Chile). Dept. de Ingenieria Electrica; Knight, U.G. [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Electrical and Electronic Engineering
1994-12-31
This paper presents a sensitivity study of the Hopf bifurcation phenomenon which can in theory appear in power systems, with reference to the dynamics of the process and the impact of demand characteristics. Conclusions are drawn regarding power levels at which these bifurcations could appear and concern the concept of the imaginary axis as a `hard` limit eigenvalue analyses. (author) 20 refs., 31 figs.
Continuous neutron slowing down theory applied to resonances
International Nuclear Information System (INIS)
Segev, M.
1977-01-01
Neutronic formalisms that discretize the neutron slowing down equations in large numerical intervals currently account for the bulk effect of resonances in a given interval by the narrow resonance approximation (NRA). The NRA reduces the original problem to an efficient numerical formalism through two assumptions: resonance narrowness with respect to the scattering bands in the slowing down equations and resonance narrowness with respect to the numerical intervals. Resonances at low energies are narrow neither with respect to the slowing down ranges nor with respect to the numerical intervals, which are usually of a fixed lethargy width. Thus, there are resonances to which the NRA is not applicable. To stay away from the NRA, the continuous slowing down (CSD) theory of Stacey was invoked. The theory is based on a linear expansion in lethargy of the collision density in integrals of the slowing down equations and had notable success in various problems. Applying CSD theory to the assessment of bulk resonance effects raises the problem of obtaining efficient quadratures for integrals involved in the definition of the so-called ''moderating parameter.'' The problem was solved by two approximations: (a) the integrals were simplified through a rationale, such that the correct integrals were reproduced for very narrow or very wide resonances, and (b) the temperature-broadened resonant line shapes were replaced by nonbroadened line shapes to enable analytical integration. The replacement was made in such a way that the integrated capture and scattering probabilities in each resonance were preserved. The resulting formalism is more accurate than the narrow-resonance formalisms and is equally as efficient
Educational measurement for applied researchers theory into practice
Wu, Margaret; Jen, Tsung-Hau
2016-01-01
This book is a valuable read for a diverse group of researchers and practitioners who analyze assessment data and construct test instruments. It focuses on the use of classical test theory (CTT) and item response theory (IRT), which are often required in the fields of psychology (e.g. for measuring psychological traits), health (e.g. for measuring the severity of disorders), and education (e.g. for measuring student performance), and makes these analytical tools accessible to a broader audience. Having taught assessment subjects to students from diverse backgrounds for a number of years, the three authors have a wealth of experience in presenting educational measurement topics, in-depth concepts and applications in an accessible format. As such, the book addresses the needs of readers who use CTT and IRT in their work but do not necessarily have an extensive mathematical background. The book also sheds light on common misconceptions in applying measurement models, and presents an integrated approach to differ...
Applying Game Theory in 802.11 Wireless Networks
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Tomas Cuzanauskas
2015-07-01
Full Text Available IEEE 802.11 is one of the most popular wireless technologies in recent days. Due to easiness of adaption and relatively low cost the demand for IEEE 802.11 devices is increasing exponentially. IEEE works in two bands 2.4 GHz and 5 GHz, these bands are known as ISM band. The unlicensed bands are managed by authority which set simple rules to follow when using unlicensed bands, the rules includes requirements as maximum power, out-of-band emissions control as well as interference mitigation. However these rules became outdated as IEEE 802.11 technology is emerging and evolving in hours the rules aren’t well suited for current capabilities of IEEE 802.11 devices. In this article we present game theory based algorithm for IEEE 802.11 wireless devices, we will show that by using game theory it’s possible to achieve better usage of unlicensed spectrum as well as partially decline CSMA/CA. Finally by using this approach we might relax the currently applied maximum power rules for ISM bands, which enable IEEE 802.11 to work on longer distance and have better propagation characteristics.
Hopf bifurcation of the stochastic model on business cycle
International Nuclear Information System (INIS)
Xu, J; Wang, H; Ge, G
2008-01-01
A stochastic model on business cycle was presented in thas paper. Simplifying the model through the quasi Hamiltonian theory, the Ito diffusion process was obtained. According to Oseledec multiplicative ergodic theory and singular boundary theory, the conditions of local and global stability were acquired. Solving the stationary FPK equation and analyzing the stationary probability density, the stochastic Hopf bifurcation was explained. The result indicated that the change of parameter awas the key factor to the appearance of the stochastic Hopf bifurcation
Discretization analysis of bifurcation based nonlinear amplifiers
Feldkord, Sven; Reit, Marco; Mathis, Wolfgang
2017-09-01
Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov-Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most relevant systems in signal processing applications. The underlying continuous-time systems are transferred to the discrete-time domain using numerical integration methods. Within this contribution, effects on the qualitative behavior of the Andronov-Hopf bifurcation based systems concerning numerical integration methods are analyzed. It is shown exemplarily that explicit Runge-Kutta methods transform the truncated normalform equation of the Andronov-Hopf bifurcation into the normalform equation of the Neimark-Sacker bifurcation. Dependent on the order of the integration method, higher order terms are added during this transformation.A rescaled normalform equation of the Neimark-Sacker bifurcation is introduced that allows a parametric design of a discrete-time system which corresponds to the rescaled Andronov-Hopf system. This system approximates the characteristics of the rescaled Hopf-type amplifier for a large range of parameters. The natural frequency and the peak amplitude are preserved for every set of parameters. The Neimark-Sacker bifurcation based systems avoid large computational effort that would be caused by applying higher order integration methods to the continuous-time normalform equations.
Discretization analysis of bifurcation based nonlinear amplifiers
Directory of Open Access Journals (Sweden)
S. Feldkord
2017-09-01
Full Text Available Recently, for modeling biological amplification processes, nonlinear amplifiers based on the supercritical Andronov–Hopf bifurcation have been widely analyzed analytically. For technical realizations, digital systems have become the most relevant systems in signal processing applications. The underlying continuous-time systems are transferred to the discrete-time domain using numerical integration methods. Within this contribution, effects on the qualitative behavior of the Andronov–Hopf bifurcation based systems concerning numerical integration methods are analyzed. It is shown exemplarily that explicit Runge–Kutta methods transform the truncated normalform equation of the Andronov–Hopf bifurcation into the normalform equation of the Neimark–Sacker bifurcation. Dependent on the order of the integration method, higher order terms are added during this transformation.A rescaled normalform equation of the Neimark–Sacker bifurcation is introduced that allows a parametric design of a discrete-time system which corresponds to the rescaled Andronov–Hopf system. This system approximates the characteristics of the rescaled Hopf-type amplifier for a large range of parameters. The natural frequency and the peak amplitude are preserved for every set of parameters. The Neimark–Sacker bifurcation based systems avoid large computational effort that would be caused by applying higher order integration methods to the continuous-time normalform equations.
The problem of applying information theory to efficient image transmission.
Sakrison, D. J.
1973-01-01
The main ideas of Shannon's (1948, 1960) theory of source encoding with a fidelity constraint, more commonly known as rate distortion theory, are summarized. The theory was specifically intended to provide a theoretical basis for efficient transmission of information such as images. What the theory has to contribute to the problem is demonstrated. Difficulties that impeded application of the theory to image transmission, and current efforts to solve these difficulties are discussed.
Hopf Bifurcation of a Differential-Algebraic Bioeconomic Model with Time Delay
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Xiaojian Zhou
2012-01-01
Full Text Available We investigate the dynamics of a differential-algebraic bioeconomic model with two time delays. Regarding time delay as a bifurcation parameter, we show that a sequence of Hopf bifurcations occur at the positive equilibrium as the delay increases. Using the theories of normal form and center manifold, we also give the explicit algorithm for determining the direction of the Hopf bifurcations and the stability of the bifurcating periodic solutions. Numerical tests are provided to verify our theoretical analysis.
Applying Information Processing Theory to Supervision: An Initial Exploration
Tangen, Jodi L.; Borders, L. DiAnne
2017-01-01
Although clinical supervision is an educational endeavor (Borders & Brown, [Borders, L. D., 2005]), many scholars neglect theories of learning in working with supervisees. The authors describe 1 learning theory--information processing theory (Atkinson & Shiffrin, 1968, 1971; Schunk, 2016)--and the ways its associated interventions may…
Optimizing Computer Assisted Instruction By Applying Principles of Learning Theory.
Edwards, Thomas O.
The development of learning theory and its application to computer-assisted instruction (CAI) are described. Among the early theoretical constructs thought to be important are E. L. Thorndike's concept of learning connectisms, Neal Miller's theory of motivation, and B. F. Skinner's theory of operant conditioning. Early devices incorporating those…
Sensitivity theory applied to a transient thermal-hydraulics problem
International Nuclear Information System (INIS)
Weber, C.F.; Oblow, E.M.
1979-10-01
A new method for sensitivity analysis of transient nonlinear problems is developed and applied to a reactor thermal-hydraulics problem. The method resembles the differential sensitivity methods currently used in the linear problems of reactor physics, but it is applicable to nonlinear systems as well. The equations governing heat transfer and fluid flow in a fuel pin and surrounding coolant are given and used to derive a second set of equations (commonly known as the adjoint equations) used in the sensitivity analysis. Both systems contain one second-order parabolic and one first-order hyperbolic partial differential equation. Difference equations are derived to approximate both systems and the convergence properties of these discrete systems are evaluated, yielding a useful analysis of the numerical solution. The solution functions are used to derive sensitivity coefficients for any desired integral response. These sensitivity coefficients are used in a first-order perturbation theory to predict changes in a response resulting from changes in parameter values. The results of a test problem are shown, verifying that this procedure is indeed useful for a wide variety of sensitivity calculations
Numerical bifurcation analysis of a class of nonlinear renewal equations
Breda, Dimitri; Diekmann, Odo; Liessi, Davide; Scarabel, Francesca
2016-01-01
We show, by way of an example, that numerical bifurcation tools for ODE yield reliable bifurcation diagrams when applied to the pseudospectral approximation of a one-parameter family of nonlinear renewal equations. The example resembles logistic-and Ricker-type population equations and exhibits
Symmetry, Hopf bifurcation, and the emergence of cluster solutions in time delayed neural networks
Wang, Zhen; Campbell, Sue Ann
2017-11-01
We consider the networks of N identical oscillators with time delayed, global circulant coupling, modeled by a system of delay differential equations with ZN symmetry. We first study the existence of Hopf bifurcations induced by the coupling time delay and then use symmetric Hopf bifurcation theory to determine how these bifurcations lead to different patterns of symmetric cluster oscillations. We apply our results to a case study: a network of FitzHugh-Nagumo neurons with diffusive coupling. For this model, we derive the asymptotic stability, global asymptotic stability, absolute instability, and stability switches of the equilibrium point in the plane of coupling time delay (τ) and excitability parameter (a). We investigate the patterns of cluster oscillations induced by the time delay and determine the direction and stability of the bifurcating periodic orbits by employing the multiple timescales method and normal form theory. We find that in the region where stability switching occurs, the dynamics of the system can be switched from the equilibrium point to any symmetric cluster oscillation, and back to equilibrium point as the time delay is increased.
International Nuclear Information System (INIS)
Olmstead, W.E.; Davis, S.H.; Rosenblat, S.; Kath, W.L.
1986-01-01
A model equation containing a memory integral is posed. The extent of the memory, the relaxation time lambda, controls the bifurcation behavior as the control parameter R is increased. Small (large) lambda gives steady (periodic) bifurcation. There is a double eigenvalue at lambda = lambda 1 , separating purely steady (lambda 1 ) from combined steady/T-periodic (lambda > lambda 1 ) states with T → infinity as lambda → lambda + 1 . Analysis leads to the co-existence of stable steady/periodic states and as R is increased, the periodic states give way to the steady states. Numerical solutions show that this behavior persists away from lambda = lambda 1
Bifurcations of transition states: Morse bifurcations
International Nuclear Information System (INIS)
MacKay, R S; Strub, D C
2014-01-01
A transition state for a Hamiltonian system is a closed, invariant, oriented, codimension-2 submanifold of an energy level that can be spanned by two compact codimension-1 surfaces of unidirectional flux whose union, called a dividing surface, locally separates the energy level into two components and has no local recrossings. For this to happen robustly to all smooth perturbations, the transition state must be normally hyperbolic. The dividing surface then has locally minimal geometric flux through it, giving an upper bound on the rate of transport in either direction. Transition states diffeomorphic to S 2m−3 are known to exist for energies just above any index-1 critical point of a Hamiltonian of m degrees of freedom, with dividing surfaces S 2m−2 . The question addressed here is what qualitative changes in the transition state, and consequently the dividing surface, may occur as the energy or other parameters are varied? We find that there is a class of systems for which the transition state becomes singular and then regains normal hyperbolicity with a change in diffeomorphism class. These are Morse bifurcations. Various examples are considered. Firstly, some simple examples in which transition states connect or disconnect, and the dividing surface may become a torus or other. Then, we show how sequences of Morse bifurcations producing various interesting forms of transition state and dividing surface are present in reacting systems, by considering a hypothetical class of bimolecular reactions in gas phase. (paper)
Hopf bifurcation analysis of Chen circuit with direct time delay feedback
International Nuclear Information System (INIS)
Hai-Peng, Ren; Wen-Chao, Li; Ding, Liu
2010-01-01
Direct time delay feedback can make non-chaotic Chen circuit chaotic. The chaotic Chen circuit with direct time delay feedback possesses rich and complex dynamical behaviours. To reach a deep and clear understanding of the dynamics of such circuits described by delay differential equations, Hopf bifurcation in the circuit is analysed using the Hopf bifurcation theory and the central manifold theorem in this paper. Bifurcation points and bifurcation directions are derived in detail, which prove to be consistent with the previous bifurcation diagram. Numerical simulations and experimental results are given to verify the theoretical analysis. Hopf bifurcation analysis can explain and predict the periodical orbit (oscillation) in Chen circuit with direct time delay feedback. Bifurcation boundaries are derived using the Hopf bifurcation analysis, which will be helpful for determining the parameters in the stabilisation of the originally chaotic circuit
Applying Learning Theories and Instructional Design Models for Effective Instruction
Khalil, Mohammed K.; Elkhider, Ihsan A.
2016-01-01
Faculty members in higher education are involved in many instructional design activities without formal training in learning theories and the science of instruction. Learning theories provide the foundation for the selection of instructional strategies and allow for reliable prediction of their effectiveness. To achieve effective learning…
Applying Diffusion of Innovation Theory to Intervention Development
Dearing, James W.
2009-01-01
Few social science theories have a history of conceptual and empirical study as long as does the diffusion of innovations. The robustness of this theory derives from the many disciplines and fields of study in which diffusion has been studied, from the international richness of these studies, and from the variety of new ideas, practices, programs,…
Decision theory applied to image quality control in radiology
Lessa, Patrícia S; Caous, Cristofer A; Arantes, Paula R; Amaro, Edson; de Souza, Fernando M Campello
2008-01-01
Abstract Background The present work aims at the application of the decision theory to radiological image quality control (QC) in diagnostic routine. The main problem addressed in the framework of decision theory is to accept or reject a film lot of a radiology service. The probability of each decision of a determined set of variables was obtained from the selected films. Methods ...
Attitude theory applied to in-store and online shopping
Dijst, M.J.; Farag, S.; Schwanen, T.
2005-01-01
In this study, we investigated whether our understanding of adoption of e-shopping and instore shopping could be advanced through the application of attitude theory. A shortcoming of the analytical frameworks and models featured in attitude theory is that they do not address the issue of what
Applying Multiple Intelligence Theory in the Music Classroom.
Mallonee, Richard L.
Howard Gardner's "Theory of Multiple Intelligences" suggests that everyone is capable of at least seven "ways" of knowing. According to this theory, human beings know the world and solve problems through: (1) language; (2) logical-mathematical analysis; (3) visual-spatial representations; (4) musical thinking; (5) the use of…
Bifurcation of transition paths induced by coupled bistable systems.
Tian, Chengzhe; Mitarai, Namiko
2016-06-07
We discuss the transition paths in a coupled bistable system consisting of interacting multiple identical bistable motifs. We propose a simple model of coupled bistable gene circuits as an example and show that its transition paths are bifurcating. We then derive a criterion to predict the bifurcation of transition paths in a generalized coupled bistable system. We confirm the validity of the theory for the example system by numerical simulation. We also demonstrate in the example system that, if the steady states of individual gene circuits are not changed by the coupling, the bifurcation pattern is not dependent on the number of gene circuits. We further show that the transition rate exponentially decreases with the number of gene circuits when the transition path does not bifurcate, while a bifurcation facilitates the transition by lowering the quasi-potential energy barrier.
Hopf Bifurcation of Compound Stochastic van der Pol System
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Shaojuan Ma
2016-01-01
Full Text Available Hopf bifurcation analysis for compound stochastic van der Pol system with a bound random parameter and Gaussian white noise is investigated in this paper. By the Karhunen-Loeve (K-L expansion and the orthogonal polynomial approximation, the equivalent deterministic van der Pol system can be deduced. Based on the bifurcation theory of nonlinear deterministic system, the critical value of bifurcation parameter is obtained and the influence of random strength δ and noise intensity σ on stochastic Hopf bifurcation in compound stochastic system is discussed. At last we found that increased δ can relocate the critical value of bifurcation parameter forward while increased σ makes it backward and the influence of δ is more sensitive than σ. The results are verified by numerical simulations.
A World Apart? Bridging the Gap between Theory and Applied Social Gerontology
Hendricks, Jon; Applebaum, Robert; Kunkel, Suzanne
2010-01-01
This article is based on the premise that there is inadequate attention to the link between theory and applied research in social gerontology. The article contends that applied research studies do not often or effectively employ a theoretical framework and that theory-based articles, including theory-based research, are not often focused on…
Storberg-Walker, Julia
2007-01-01
This article presents a provisional grounded theory of conceptual development for applied theory-building research. The theory described here extends the understanding of the components of conceptual development and provides generalized relations among the components. The conceptual development phase of theory-building research has been widely…
Learning Theories Applied to the Teaching of Business Communication.
Hart, Maxine Barton
1980-01-01
Reviews major learning theories that can be followed by business communication instructors, including those by David Ausubel, Albert Bandura, Kurt Lewin, Edward Thorndike, B.F. Skinner, and Robert Gagne. (LRA)
Energetics and monsoon bifurcations
Seshadri, Ashwin K.
2017-01-01
Monsoons involve increases in dry static energy (DSE), with primary contributions from increased shortwave radiation and condensation of water vapor, compensated by DSE export via horizontal fluxes in monsoonal circulations. We introduce a simple box-model characterizing evolution of the DSE budget to study nonlinear dynamics of steady-state monsoons. Horizontal fluxes of DSE are stabilizing during monsoons, exporting DSE and hence weakening the monsoonal circulation. By contrast latent heat addition (LHA) due to condensation of water vapor destabilizes, by increasing the DSE budget. These two factors, horizontal DSE fluxes and LHA, are most strongly dependent on the contrast in tropospheric mean temperature between land and ocean. For the steady-state DSE in the box-model to be stable, the DSE flux should depend more strongly on the temperature contrast than LHA; stronger circulation then reduces DSE and thereby restores equilibrium. We present conditions for this to occur. The main focus of the paper is describing conditions for bifurcation behavior of simple models. Previous authors presented a minimal model of abrupt monsoon transitions and argued that such behavior can be related to a positive feedback called the `moisture advection feedback'. However, by accounting for the effect of vertical lapse rate of temperature on the DSE flux, we show that bifurcations are not a generic property of such models despite these fluxes being nonlinear in the temperature contrast. We explain the origin of this behavior and describe conditions for a bifurcation to occur. This is illustrated for the case of the July-mean monsoon over India. The default model with mean parameter estimates does not contain a bifurcation, but the model admits bifurcation as parameters are varied.
Yang, Dong-Ping; Robinson, P A
2017-04-01
A physiologically based corticothalamic model of large-scale brain activity is used to analyze critical dynamics of transitions from normal arousal states to epileptic seizures, which correspond to Hopf bifurcations. This relates an abstract normal form quantitatively to underlying physiology that includes neural dynamics, axonal propagation, and time delays. Thus, a bridge is constructed that enables normal forms to be used to interpret quantitative data. The normal form of the Hopf bifurcations with delays is derived using Hale's theory, the center manifold theorem, and normal form analysis, and it is found to be explicitly expressed in terms of transfer functions and the sensitivity matrix of a reduced open-loop system. It can be applied to understand the effect of each physiological parameter on the critical dynamics and determine whether the Hopf bifurcation is supercritical or subcritical in instabilities that lead to absence and tonic-clonic seizures. Furthermore, the effects of thalamic and cortical nonlinearities on the bifurcation type are investigated, with implications for the roles of underlying physiology. The theoretical predictions about the bifurcation type and the onset dynamics are confirmed by numerical simulations and provide physiologically based criteria for determining bifurcation types from first principles. The results are consistent with experimental data from previous studies, imply that new regimes of seizure transitions may exist in clinical settings, and provide a simplified basis for control-systems interventions. Using the normal form, and the full equations from which it is derived, more complex dynamics, such as quasiperiodic cycles and saddle cycles, are discovered near the critical points of the subcritical Hopf bifurcations.
APPLYING THE THEORY OF CONSTRAINTS TO INCREASE ECONOMIC VALUE ADDED: PART 1—THEORY
Directory of Open Access Journals (Sweden)
Malan Smith
2012-01-01
Full Text Available
ENGLISH ABSTRACT: This article, presented in two parts, explains how to apply the Theory of Constraints (TOC in a business to increase Economic Value Added (EVA. The first part deals with the theory, while the second part deals with the implementation. The goal of a business, the measurements of the goal and the priority of the measurements are discussed. The future reality of a company which implements TOC principles is shown through cause and effect to lead to an increase in EVA. The increase in EVA is caused by an increase in return on investment and a reduction in the cost of capital. The actions the company must take to increase EVA is presented.
AFRIKAANSE OPSOMMING: Hierdie artikel, aangebied in twee dele, verduidelik hoe om die Teorie van Beperkinge (TVB in a besigheid toe te pas om Ekonomiese Toegevoegde Waarde (ETW te vermeerder. Die eerste gedeelte verduidelik die teorie, terwyl die tweede gedeelte die toepassing hanteer. Die doel van ’n besigheid, die maatstawwe van die doel en die prioriteit van die maatstawwe word bespreek. Deur middel van oorsaak en effek word gewys dat die toekomstige werklikheid van ’n besigheid wat TVB beginsels toepas lei tot ’n toename in ETW. Die toename in ETW word veroorsaak deur ’n toename in opbrengs op belegging en ’n afname in die koste van kapitaal. Die aksies wat ’n besigheid moet neem om ETW te vermeerder, word genoem.
The interpersonal theory of suicide applied to male prisoners.
Mandracchia, Jon T; Smith, Phillip N
2015-06-01
The interpersonal theory of suicide proposes that severe suicide ideation is caused by the combination of thwarted belongingness (TB) and perceived burdensomeness (PB), yet few studies have actually examined their interaction. Further, no studies have examined this proposal in male prisoners, a particularly at-risk group. To address this gap, the current study surveyed 399 male prisoners. TB and PB interacted to predict suicide ideation while controlling for depression and hopelessness. High levels of both TB and PB were associated with more severe suicide ideation. The interpersonal theory may aid in the detection, prevention, and treatment of suicide risk in prisoners. © 2014 The American Association of Suicidology.
Bifurcation diagram of a cubic three-parameter autonomous system
Directory of Open Access Journals (Sweden)
Lenka Barakova
2005-07-01
Full Text Available In this paper, we study the cubic three-parameter autonomous planar system $$displaylines{ dot x_1 = k_1 + k_2x_1 - x_1^3 - x_2,cr dot x_2 = k_3 x_1 - x_2, }$$ where $k_2, k_3$ are greater than 0. Our goal is to obtain a bifurcation diagram; i.e., to divide the parameter space into regions within which the system has topologically equivalent phase portraits and to describe how these portraits are transformed at the bifurcation boundaries. Results may be applied to the macroeconomical model IS-LM with Kaldor's assumptions. In this model existence of a stable limit cycles has already been studied (Andronov-Hopf bifurcation. We present the whole bifurcation diagram and among others, we prove existence of more difficult bifurcations and existence of unstable cycles.
Marketing Theory Applied to Price Discrimination in Journals.
Talaga, James; Haley, Jean Walstrom
1991-01-01
Discussion of discriminatory pricing by journal publishers and its effects on libraries focuses on six prerequisites for successful discriminatory pricing that are based on marketing theory. Strategies to eliminate some of these prerequisites--and therefore eliminate discriminatory pricing--are suggested, including the need to change the attitudes…
Influencing Organizations to Promote Health: Applying Stakeholder Theory
Kok, Gerjo; Gurabardhi, Zamira; Gottlieb, Nell H.; Zijlstra, Fred R. H.
2015-01-01
Stakeholder theory may help health promoters to make changes at the organizational and policy level to promote health. A stakeholder is any individual, group, or organization that can influence an organization. The organization that is the focus for influence attempts is called the focal organization. The more salient a stakeholder is and the more…
Applying Learning Theory to Musical Development: Piaget and Beyond.
Warrener, John J.
1985-01-01
How Piaget's theory of developmental stages affects the musical ability of children at different ages is important for the music educator to understand. The following developmental stages are discussed: sensorimotor period, preoperations period, concrete operations period, formal operations period, and creative stage. (RM)
Rethinking wave-kinetic theory applied to zonal flows
Parker, Jeffrey
2017-10-01
Over the past two decades, a number of studies have employed a wave-kinetic theory to describe fluctuations interacting with zonal flows. Recent work has uncovered a defect in this wave-kinetic formulation: the system is dominated by the growth of (arbitrarily) small-scale zonal structures. Theoretical calculations of linear growth rates suggest, and nonlinear simulations confirm, that this system leads to the concentration of zonal flow energy in the smallest resolved scales, irrespective of the numerical resolution. This behavior results from the assumption that zonal flows are extremely long wavelength, leading to the neglect of key terms responsible for conservation of enstrophy. A corrected theory, CE2-GO, is presented; it is free of these errors yet preserves the intuitive phase-space mathematical structure. CE2-GO properly conserves enstrophy as well as energy, and yields accurate growth rates of zonal flow. Numerical simulations are shown to be well-behaved and not dependent on box size. The steady-state limit simplifies into an exact wave-kinetic form which offers the promise of deeper insight into the behavior of wavepackets. The CE2-GO theory takes its place in a hierarchy of models as the geometrical-optics reduction of the more complete cumulant-expansion statistical theory CE2. The new theory represents the minimal statistical description, enabling an intuitive phase-space formulation and an accurate description of turbulence-zonal flow dynamics. This work was supported by an NSF Graduate Research Fellowship, a US DOE Fusion Energy Sciences Fellowship, and US DOE Contract Nos. DE-AC52-07NA27344 and DE-AC02-09CH11466.
Intelligent mathematics II applied mathematics and approximation theory
Duman, Oktay
2016-01-01
This special volume is a collection of outstanding more applied articles presented in AMAT 2015 held in Ankara, May 28-31, 2015, at TOBB Economics and Technology University. The collection is suitable for Applied and Computational Mathematics and Engineering practitioners, also for related graduate students and researchers. Furthermore it will be a useful resource for all science and engineering libraries. This book includes 29 self-contained and well-edited chapters that can be among others useful for seminars in applied and computational mathematics, as well as in engineering.
An imperfect bifurcation problem
Descloux, J.
The problem considered in the present investigation involves the motion of a beam rotating around an axis at constant angular velocity. It is assumed that the beam, in its rest position, does not coincide exactly with the axis. This case leads to an imperfect bifurcation problem. The current investigation has the objective to provide a numerical approximation regarding the conditions in the considered situation. A finite difference scheme is discussed, taking into account the classical two-points boundary value problem. Attention is given to the relations concerning perfect and imperfect bifurcations, a theorem with respect to the existence of solutions for the considered problem, and the proof of this theorem. The physical problem considered involves a satellite with an antenna.
DEFF Research Database (Denmark)
Hansen, Morten Balle; Heilesen, J. B.
In the broader context of evaluation design, this paper examines and compares pros and cons of a theory-based approach to evaluation (TBE) with the Theory-Based Stakeholder evaluation (TSE) model, introduced by Morten Balle Hansen and Evert Vedung (Hansen and Vedung 2010). While most approaches...... to TBE construct one unitary theory of the program (Coryn et al. 2011), the TSE-model emphasizes the importance of keeping theories of diverse stakeholders apart. This paper applies the TSE-model to an evaluation study conducted by the Danish Evaluation Institute (EVA) of the Danish system of quality......-model, as an alternative to traditional program theory evaluation....
How Could Nurse Researchers Apply Theory to Generate Knowledge More Efficiently?
Lor, Maichou; Backonja, Uba; Lauver, Diane R
2017-09-01
Reports of nursing research often do not provide adequate information about whether, and how, researchers applied theory when conducting their studies. Unfortunately, the lack of adequate application and explication of theory in research impedes development of knowledge to guide nursing practice. To clarify and exemplify how to apply theory in research. First we describe how researchers can apply theory in phases of research. Then we share examples of how three research teams applied one theory to these phases of research in three different studies of preventive behaviors. Nurse researchers can review and refine ways in which they apply theory in guiding research and writing publications. Scholars can appreciate how one theory can guide researchers in building knowledge about a given condition such as preventive behaviors. Clinicians and researchers can collaborate to apply and examine the usefulness of theory. If nurses had improved understanding of theory-guided research, they could better assess, select, and apply theory-guided interventions in their practices. © 2017 Sigma Theta Tau International.
Applying Humanistic Learning Theory: The "Art" of Coaching
Connolly, Graeme J.
2016-01-01
The purpose of this article is to apply specific principles of psychology to the coaching process. More specifically, it is about becoming a productive and effective coach, who positively affects the athletic careers and lives of young people.
Applying Graph Theory to Problems in Air Traffic Management
Farrahi, Amir H.; Goldberg, Alan T.; Bagasol, Leonard N.; Jung, Jaewoo
2017-01-01
Graph theory is used to investigate three different problems arising in air traffic management. First, using a polynomial reduction from a graph partitioning problem, it isshown that both the airspace sectorization problem and its incremental counterpart, the sector combination problem are NP-hard, in general, under several simple workload models. Second, using a polynomial time reduction from maximum independent set in graphs, it is shown that for any fixed e, the problem of finding a solution to the minimum delay scheduling problem in traffic flow management that is guaranteed to be within n1-e of the optimal, where n is the number of aircraft in the problem instance, is NP-hard. Finally, a problem arising in precision arrival scheduling is formulated and solved using graph reachability. These results demonstrate that graph theory provides a powerful framework for modeling, reasoning about, and devising algorithmic solutions to diverse problems arising in air traffic management.
The Interpersonal Theory of Suicide Applied to Male Prisoners
Mandracchia, Jon T.; Smith, Phillip N.
2014-01-01
The interpersonal theory of suicide proposes that severe suicidal ideation is caused by the combination of thwarted belongingness (TB) and perceived burdensomeness (PB), yet few studies have actually examined their interaction. Further, no studies have examined this proposal in male prisoners, a particularly at-risk group. To address this gap, the current study surveyed 399 male prisoners. TB and PB interacted to predict suicidal ideation while controlling for depression and hopelessness. Hig...
3rd International Conference on Applied Mathematics and Approximation Theory
Duman, Oktay
2016-01-01
This special volume is a collection of outstanding theoretical articles presented at the conference AMAT 2015, held in Ankara, Turkey from May 28-31, 2015, at TOBB University of Economics and Technology. The collection is suitable for a range of applications: from researchers and practitioners of applied and computational mathematics, to students in graduate-level seminars. Furthermore it will be a useful resource for all science libraries. This book includes 27 self-contained and expertly-refereed chapters that provide numerous insights into the latest developments at the intersection of applied and computational mathematics, engineering, and statistics.
Moving beyond the "exotic": applying postcolonial theory in health research.
Mohammed, Selina A
2006-01-01
Postcolonialism offers nursing scholarship a framework for understanding culture and identity as fluid and complex, historically situated, and discursively constructed. This article describes one version of implementing postcolonial theory, using examples from a research project conducted with urban American Indians on the topic of diabetes. I demonstrate the influence and value of postcolonialism throughout the research process. A postcolonial approach can help nursing researchers and practitioners avoid reproducing injustices and stereotypes, illuminate the complexities of life at the intersections, and contribute to the construction of a more socially just world.
Action Learning in Virtual Higher Education: Applying Leadership Theory
Curtin, Joseph
2016-01-01
This paper reports the historical foundation of Northeastern University's course, LDR 6100: Developing Your Leadership Capability, a partial literature review of action learning (AL) and virtual action learning (VAL), a course methodology of LDR 6100 requiring students to apply leadership perspectives using VAL as instructed by the author,…
Fuzzy set theory applied to bend sequencing for sheet metal
Ong, S.K.; de Vin, L.J.; de Vin, L.J.; Nee, A.Y.C.; Kals, H.J.J.
1997-01-01
Brake forming is widely applied in the high variety and small batch part manufacturing of sheet metal components, for the bending of straight bending lines. Currently, the planning of the bending sequences is a task that has to be performed manually, involving many heuristic criteria. However,
Applying Organizational Commitment and Human Capital Theories to Emigration Research
Verkhohlyad, Olga; McLean, Gary N.
2012-01-01
Purpose: This study aims to bring some additional insight into the issue of emigration by establishing a relationship between emigration and psychic return of citizens to their human capital investment in the country. Design/methodology/approach: The article adopts a quantitative research strategy. It applies organizational commitment and human…
An Applied Relevance Theory of the Making and Understanding of Rhetorical Arguments.
Campbell, J. L.
1992-01-01
Relevance theory in linguistic pragmatics is applied to the field of rhetorical argument. The applied theory allows for multiple coincidental relevances (strategic, rational, and worldly) during the communication of arguments corresponding to horizons of awareness with regard to which arguments are made and understood. (32 references) (LB)
Finding the Right Fit: Helping Students Apply Theory to Service-Learning Contexts
Ricke, Audrey
2018-01-01
Background: Although past studies of service-learning focus on assessing student growth, few studies address how to support students in applying theory to their service-learning experiences. Yet, the task of applying theory is a central component of critical reflections within the social sciences in higher education and often causes anxiety among…
Enhanced Thomson scattering theory applied to eight experiments
International Nuclear Information System (INIS)
Simon, A.; Short, R.W.; Seka, W.; Goldman, L.M.
1985-01-01
The onset of an instability, such as the 2ω/sub p/ at the n/sub c//4 surface, usually leads to wave breaking and the emission of hot electron pulses which can profoundly influence instability thresholds and scattering behavior elsewhere in the plasma. In particular, enhanced Thomson scattering (via the plasma line) can occur, and this has been used to explain the observation of the SRS instability well below the theoretical threshold. A simple model of the hot electron pulses based on measured values of the hot and cold electron temperatures, T/sub h/ and T/sub c/, has yielded good agreement with experimental observation of the Raman spectral frequency bands. The agreement has continued, even for experiments which are clearly above the SRS threshold, with the enhanced noise likely acting as a ''seed'' for the SRS growth. We will show details of the successful comparison of this theory with six experiments carried out on SHIVA, ARGUS, NOVETTE(2), and GDL(2), and also with an upscattering feature seen at Garching. In addition, a recent experiment using 6 beams of OMEGA (at 0.35μ) will be discussed, and compared with the theory. The report is comprised of viewgraphs of the talks
Liu, Xia; Zhang, Tonghua; Meng, Xinzhu; Zhang, Tongqian
2018-04-01
In this paper, we propose a predator-prey model with herd behavior and prey-taxis. Then, we analyze the stability and bifurcation of the positive equilibrium of the model subject to the homogeneous Neumann boundary condition. By using an abstract bifurcation theory and taking prey-tactic sensitivity coefficient as the bifurcation parameter, we obtain a branch of stable nonconstant solutions bifurcating from the positive equilibrium. Our results show that prey-taxis can yield the occurrence of spatial patterns.
Adaptive Leadership Theories Applied to the North Atlantic Treaty Organization (NATO)
2011-03-07
Adaptive Leadership Theories Applied to the North Atlantic Treaty Organization (NATO) By Major Christopher J. Wehri Essay...DATE 07 MAR 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Adaptive Leadership Theories Applied to the...the culturally diverse European environment. To solve its organizational problems NATO must consider various adaptive leadership theories and
Does Social Value Orientation Theory Apply to Social Relations?
Directory of Open Access Journals (Sweden)
Patricia Danielle Lewis
2017-03-01
Full Text Available This research asks whether Social Value Orientations (SVOs apply to the social relations of exchange networks. SVO literature identifies three types of orientation to rational action, determined by how actors value outcomes to self and other. Only the individualist is the self-interested, rational actor previously seen in exchange networks. The prosocial actor seeks to maximize joint outcomes and equality whereas the competitor seeks to maximize differences between self and other. The competitor and individualist are frequently collapsed into a proself type. Whereas SVO research has focused on games and social dilemmas, this research places prosocials and proselfs in equal, weak, and strong power exchange structures. We show that, if SVO applies, the behaviors of proself and prosocial will be very different. Experimental results demonstrate, however, that prosocials’ actions in exchanges are indistinguishable from activities of proselfs.
Applied linguistics, performance theory, and Muhammad Ali's Japanese failure
Miracle, Jared
2017-01-01
One of the more colorful realizations of the age-old striking versus grappling rivalry came in 1976, in a fight billed as boxing versus professional wrestling. Unlike similar matches throughout history, however, this event featured the heavyweight world champion, Muhammad Ali, and the most popular Japanese professional wrestler of the day, Antonio Inoki.\\ud \\ud Investigating this event through the lens of applied linguistic anthropology reveals much about the contextual social dynamics at pla...
Random walk theory applied to electron avalanche formation
Englert, G. W.
1974-01-01
Use of microscopic detail in random walk theory describing the initial formations of a large number of avalanches shows that concomitant electron transport coefficients quickly relax to equilibrium values. This enables the use of random walks having step sizes and probabilities based only on local electric field strengths and densities. A self-consistent avalanche solution which accounts for collective long range Coulomb interactions as well as short range elastic and inelastic collisions between electrons and background atoms is demonstrated for helium. Avalanche growth retardation followed by an abrupt growth augmentation as time proceeds is shown to be associated with the formation of regions of charge density extrema near the avalanche axis and within the axial distance covered by the electron swarm.
Theory of sheared flow generation by applied radio frequency waves
International Nuclear Information System (INIS)
Myra, J. R.; D'Ippolito, D. A.
1999-01-01
The possibility of employing rf to generate sheared flows in the edge plasma is of great interest as a means of accessing improved regimes of tokamak confinement. Here, we develop an electromagnetic nonlinear eikonal theory (with k perpendicular ρ∼1 and k/k unrestricted) of the rf force terms which drive poloidal flow. Various cancellations, e.g., amongst parts of the electromagnetic and Reynolds stress terms, are exhibited analytically. At the heart of our calculation is the derivation of the nonlinear kinetic pressure tensor Π. A general expression for Π is obtained in terms of simple moments of the linear distribution function. In the electrostatic limit, the resulting nonlinear forces are expressible entirely in terms of the linear dielectric susceptibility tensor χ. Application to the ion Bernstein wave case, with retention of all Bessel function sums, is presented. Comparison is made to simpler approximate calculations
Fostering engagement during termination: Applying attachment theory and research.
Marmarosh, Cheri L
2017-03-01
Therapists often struggle to determine the most important things to focus on during termination. Reviewing the treatment, identifying plans for the future, summarizing positive gains, and saying goodbye receive the most attention. Despite our best intentions, termination can end up becoming intellectualized. Attachment theory and recent developments in neuroscience offer us a road map for facilitating endings that address client's underlying relational needs, direct us to foster engagement, and help us facilitate new relational experience that can be transformative for clients. We argue that endings in therapy activate client's and therapist's attachments and these endings trigger emotion regulating strategies that can elicit client's engagement or more defensiveness. The current paper will highlight through de-identified case examples how clients automatically respond termination and how therapists can foster rich relational experiences in the here-and-now that clients can take with them. (PsycINFO Database Record (c) 2017 APA, all rights reserved).
Bogdanov-Takens bifurcation in a predator-prey model
Liu, Zhihua; Magal, Pierre; Xiao, Dongmei
2016-12-01
In this paper, we investigate a class of predator-prey model with age structure and discuss whether the model can undergo Bogdanov-Takens bifurcation. The analysis is based on the normal form theory and the center manifold theory for semilinear equations with non-dense domain combined with integrated semigroup theory. Qualitative analysis indicates that there exist some parameter values such that this predator-prey model has an unique positive equilibrium which is Bogdanov-Takens singularity. Moreover, it is shown that under suitable small perturbation, the system undergoes the Bogdanov-Takens bifurcation in a small neighborhood of this positive equilibrium.
Local and global Hopf bifurcation analysis in a neutral-type neuron system with two delays
Lv, Qiuyu; Liao, Xiaofeng
2018-03-01
In recent years, neutral-type differential-difference equations have been applied extensively in the field of engineering, and their dynamical behaviors are more complex than that of the delay differential-difference equations. In this paper, the equations used to describe a neutral-type neural network system of differential difference equation with two delays are studied (i.e. neutral-type differential equations). Firstly, by selecting τ1, τ2 respectively as a parameter, we provide an analysis about the local stability of the zero equilibrium point of the equations, and sufficient conditions of asymptotic stability for the system are derived. Secondly, by using the theory of normal form and applying the theorem of center manifold introduced by Hassard et al., the Hopf bifurcation is found and some formulas for deciding the stability of periodic solutions and the direction of Hopf bifurcation are given. Moreover, by applying the theorem of global Hopf bifurcation, the existence of global periodic solution of the system is studied. Finally, an example is given, and some computer numerical simulations are taken to demonstrate and certify the correctness of the presented results.
Extreme Value Theory Applied to the Millennial Sunspot Number Series
Acero, F. J.; Gallego, M. C.; García, J. A.; Usoskin, I. G.; Vaquero, J. M.
2018-01-01
In this work, we use two decadal sunspot number series reconstructed from cosmogenic radionuclide data (14C in tree trunks, SN 14C, and 10Be in polar ice, SN 10Be) and the extreme value theory to study variability of solar activity during the last nine millennia. The peaks-over-threshold technique was used to compute, in particular, the shape parameter of the generalized Pareto distribution for different thresholds. Its negative value implies an upper bound of the extreme SN 10Be and SN 14C timeseries. The return level for 1000 and 10,000 years were estimated leading to values lower than the maximum observed values, expected for the 1000 year, but not for the 10,000 year return levels, for both series. A comparison of these results with those obtained using the observed sunspot numbers from telescopic observations during the last four centuries suggests that the main characteristics of solar activity have already been recorded in the telescopic period (from 1610 to nowadays) which covers the full range of solar variability from a Grand minimum to a Grand maximum.
One-Group Perturbation Theory Applied to Measurements with Void
Energy Technology Data Exchange (ETDEWEB)
Persson, Rolf
1966-09-15
Formulas suitable for evaluating progressive as well as single rod substitution measurements are derived by means of one-group perturbation theory. The diffusion coefficient may depend on direction and position. By using the buckling concept one can derive expressions which are quite simple and the perturbed flux can be taken into account in a comparatively simple way. By using an unconventional definition of cells a transition region is introduced quite logically. Experiments with voids around metal rods, diam. 3.05 cm, have been analysed. The agreement between extrapolated and directly measured buckling values is excellent, the buckling difference between lattices with water-filled and voided shrouds being 0. 263 {+-} 0.015/m{sup 2} and 0.267 {+-} 0.005/m{sup 2} resp. From single-rod experiments differences between diffusion coefficients are determined to {delta}D{sub r}/D = 0.083 {+-} 0.004 and {delta}D{sub z}/D = 0.120 {+-} 0.018. With air-filled shrouds there is consequently anisotropy in the neutron diffusion and we have (D{sub z}/D{sub r}){sub air} = 1.034 {+-} 0.020.
Artificial Intelligence and Systems Theory: Applied to Cooperative Robots
Directory of Open Access Journals (Sweden)
Pedro U. Lima
2004-09-01
Full Text Available This paper describes an approach to the design of a population of cooperative robots based on concepts borrowed from Systems Theory and Artificial Intelligence. The research has been developed under the SocRob project, carried out by the Intelligent Systems Laboratory at the Institute for Systems and Robotics - Instituto Superior Técnico (ISR/IST in Lisbon. The acronym of the project stands both for “Society of Robots” and “Soccer Robots”, the case study where we are testing our population of robots. Designing soccer robots is a very challenging problem, where the robots must act not only to shoot a ball towards the goal, but also to detect and avoid static (walls, stopped robots and dynamic (moving robots obstacles. Furthermore, they must cooperate to defeat an opposing team. Our past and current research in soccer robotics includes cooperative sensor fusion for world modeling, object recognition and tracking, robot navigation, multi-robot distributed task planning and coordination, including cooperative reinforcement learning in cooperative and adversarial environments, and behavior-based architectures for real time task execution of cooperating robot teams.
Artificial Intelligence and Systems Theory: Applied to Cooperative Robots
Directory of Open Access Journals (Sweden)
Pedro U. Lima
2008-11-01
Full Text Available This paper describes an approach to the design of a population of cooperative robots based on concepts borrowed from Systems Theory and Artificial Intelligence. The research has been developed under the SocRob project, carried out by the Intelligent Systems Laboratory at the Institute for Systems and Robotics - Instituto Superior T?cnico (ISR/IST in Lisbon. The acronym of the project stands both for "Society of Robots" and "Soccer Robots", the case study where we are testing our population of robots. Designing soccer robots is a very challenging problem, where the robots must act not only to shoot a ball towards the goal, but also to detect and avoid static (walls, stopped robots and dynamic (moving robots obstacles. Furthermore, they must cooperate to defeat an opposing team. Our past and current research in soccer robotics includes cooperative sensor fusion for world modeling, object recognition and tracking, robot navigation, multi-robot distributed task planning and coordination, including cooperative reinforcement learning in cooperative and adversarial environments, and behavior-based architectures for real time task execution of cooperating robot teams.
One-Group Perturbation Theory Applied to Measurements with Void
International Nuclear Information System (INIS)
Persson, Rolf
1966-09-01
Formulas suitable for evaluating progressive as well as single rod substitution measurements are derived by means of one-group perturbation theory. The diffusion coefficient may depend on direction and position. By using the buckling concept one can derive expressions which are quite simple and the perturbed flux can be taken into account in a comparatively simple way. By using an unconventional definition of cells a transition region is introduced quite logically. Experiments with voids around metal rods, diam. 3.05 cm, have been analysed. The agreement between extrapolated and directly measured buckling values is excellent, the buckling difference between lattices with water-filled and voided shrouds being 0. 263 ± 0.015/m 2 and 0.267 ± 0.005/m 2 resp. From single-rod experiments differences between diffusion coefficients are determined to δD r /D = 0.083 ± 0.004 and δD z /D = 0.120 ± 0.018. With air-filled shrouds there is consequently anisotropy in the neutron diffusion and we have (D z /D r ) air = 1.034 ± 0.020
Applying Bourdieu’s Field Theory to MLS Curricula Development
DEFF Research Database (Denmark)
Wien, Charlotte; Dorch, Bertil F.
Our research question is: How can adequate education in Library and Information Science be provided for subject specialists in research libraries under constant change? Research libraries may be one of the places where imprints of the transition from industrial society to knowledge society are most...... evident. In order to keep up, the library profession has had to incorporate numerous new disciplines and has become a highly specialized area with its own Ph.D. program. But while developing the curricula within the discipline of library and information science (LIS), the training programs for the subject...... specialists of the research libraries tend to have been neglected in Denmark. Until the turn of the millennium, a subject specialist in a Danish research library would typically start their career by applying for a vacancy in connection with a subject specialist’s MA or Ph.D. specialization...
Global Hopf Bifurcation for a Predator-Prey System with Three Delays
Jiang, Zhichao; Wang, Lin
2017-06-01
In this paper, a delayed predator-prey model is considered. The existence and stability of the positive equilibrium are investigated by choosing the delay τ = τ1 + τ2 as a bifurcation parameter. We see that Hopf bifurcation can occur as τ crosses some critical values. The direction of the Hopf bifurcations and the stability of the bifurcation periodic solutions are also determined by using the center manifold and normal form theory. Furthermore, based on the global Hopf bifurcation theorem for general function differential equations, which was established by J. Wu using fixed point theorem and degree theory methods, the existence of global Hopf bifurcation is investigated. Finally, numerical simulations to support the analytical conclusions are carried out.
Directory of Open Access Journals (Sweden)
Jonathan Matusitz
2011-01-01
Full Text Available The purpose of this paper is to apply three communication theories (namely, Argumentation Theory, the Foot-in-the-Door Technique, and the Door-in-the-Face Technique to the formulation of complaints that communicate effectively to company employees and yield compensation for the consumer. What the authors demonstrate is that complaining is not a haphazard procedure if communication theories are applied properly. In addition, also emphasized is the importance of self-efficacy, as a psychological component, to illustrate the necessity for complainers to have sufficient and trueself-confidence in order to carry out each of these theories in practice.
Reed, Cajah S.
2012-01-01
This study sought to find evidence for a beneficial learning theory to teach computer software programs. Additionally, software was analyzed for each learning theory's applicability to resolve whether certain software requires a specific method of education. The results are meant to give educators more effective teaching tools, so students…
Bubble transport in bifurcations
Bull, Joseph; Qamar, Adnan
2017-11-01
Motivated by a developmental gas embolotherapy technique for cancer treatment, we examine the transport of bubbles entrained in liquid. In gas embolotherapy, infarction of tumors is induced by selectively formed vascular gas bubbles that originate from acoustic vaporization of vascular droplets. In the case of non-functionalized droplets with the objective of vessel occlusion, the bubbles are transported by flow through vessel bifurcations, where they may split prior to eventually reach vessels small enough that they become lodged. This splitting behavior affects the distribution of bubbles and the efficacy of flow occlusion and the treatment. In these studies, we investigated bubble transport in bifurcations using computational and theoretical modeling. The model reproduces the variety of experimentally observed splitting behaviors. Splitting homogeneity and maximum shear stress along the vessel walls is predicted over a variety of physical parameters. Maximum shear stresses were found to decrease with increasing Reynolds number. The initial bubble length was found to affect the splitting behavior in the presence of gravitational asymmetry. This work was supported by NIH Grant R01EB006476.
Stability and Hopf Bifurcation in a Delayed SEIRS Worm Model in Computer Network
Directory of Open Access Journals (Sweden)
Zizhen Zhang
2013-01-01
Full Text Available A delayed SEIRS epidemic model with vertical transmission in computer network is considered. Sufficient conditions for local stability of the positive equilibrium and existence of local Hopf bifurcation are obtained by analyzing distribution of the roots of the associated characteristic equation. Furthermore, the direction of the local Hopf bifurcation and the stability of the bifurcating periodic solutions are determined by using the normal form theory and center manifold theorem. Finally, a numerical example is presented to verify the theoretical analysis.
Stability and Hopf Bifurcation for a Delayed Computer Virus Model with Antidote in Vulnerable System
Directory of Open Access Journals (Sweden)
Zizhen Zhang
2017-01-01
Full Text Available A delayed computer virus model with antidote in vulnerable system is investigated. Local stability of the endemic equilibrium and existence of Hopf bifurcation are discussed by analyzing the associated characteristic equation. Further, direction of the Hopf bifurcation and stability of the bifurcating periodic solutions are investigated by using the normal form theory and the center manifold theorem. Finally, numerical simulations are presented to show consistency with the obtained results.
Connor, Joseph P; Troendle, Karen
2007-08-01
This article applies two well-known management and leadership models-Theory X and Theory Y, and Situational Leadership-to dental education. Theory X and Theory Y explain how assumptions may shape the behaviors of dental educators and lead to the development of "cop" and "coach" teaching styles. The Situational Leadership Model helps the educator to identify the teaching behaviors that are appropriate in a given situation to assist students as they move from beginner to advanced status. Together, these models provide a conceptual reference to assist in the understanding of the behaviors of both students and faculty and remind us to apply discretion in the education of our students. The implications of these models for assessing and enhancing the educational environment in dental school are discussed.
The theory of interpersonal relations applied to the preceptor-new graduate relationship.
Washington, Georgita T
2013-01-01
This article presents research results applying Peplau's Theory of Interpersonal Relations to the preceptor-new graduate relationship and describes implications for successful transition. These results will help nursing professional development educators with more appropriate preparation and assignment of preceptors.
Applied Systemic Theory and Educational Psychology: Can the Twain Ever Meet?
Pellegrini, Dario W.
2009-01-01
This article reflects on the potential benefits of applying systemic theory to the work of educational psychologists (EPs). It reviews developments in systemic thinking over time, and discusses the differences between more directive "first order" versus collaborative "second order" approaches. It considers systemic theories and…
Masculinity Theory in Applied Research with Men and Boys with Intellectual Disability
Wilson, Nathan John; Shuttleworth, Russell; Stancliffe, Roger; Parmenter, Trevor
2012-01-01
Researchers in intellectual disability have had limited theoretical engagement with mainstream theories of masculinity. In this article, the authors consider what mainstream theories of masculinity may offer to applied research on, and hence to therapeutic interventions with, men and boys with intellectual disability. An example from one research…
Applying Social Cognitive Theory in Coaching Athletes: The Power of Positive Role Models
Connolly, Graeme J.
2017-01-01
The purpose of this article is to help coaches apply specific principles of psychology to the coaching process. More specifically, the work of Albert Bandura and his social cognitive theory form the basis for the article. This article begins with a brief overview of Bandura's social cognitive theory. It then examines four types of behaviors worthy…
How Settings Change People: Applying Behavior Setting Theory to Consumer-Run Organizations
Brown, Louis D.; Shepherd, Matthew D.; Wituk, Scott A.; Meissen, Greg
2007-01-01
Self-help initiatives stand as a classic context for organizational studies in community psychology. Behavior setting theory stands as a classic conception of organizations and the environment. This study explores both, applying behavior setting theory to consumer-run organizations (CROs). Analysis of multiple data sets from all CROs in Kansas…
Summaries of FY 1986 research in the Applied Plasma Physics Fusion Theory Program
International Nuclear Information System (INIS)
1987-12-01
The Theory Program is charged with supporting the development of theories and models of plasmas for the fusion research effort. This work ranges from first-principles analysis of elementary plasma processes to empirical simulation of specific experiments. The Theory Program supports research by industrial contractors, US government laboratories, and universities. The university support also helps to fulfill the DOE mission of training scientists for the fusion program. The Theory Program is funded through the Fusion Theory Branch, Division of Applied Plasma Physics in the Office of Fusion Energy. The work is divided among 31 institutions, of which 19 are universities, five are industrial contractors, and seven are US government laboratories; see Table 1 for a complete list. The FY 1986 Theory Program budget was divided among theory types: toroidal, mirror, alternate concept, generic, and atomic. Device modeling is included among the other funding categories, and is not budgeted separately
Bifurcation analysis of an automobile model negotiating a curve
Della Rossa, Fabio; Mastinu, Giampiero; Piccardi, Carlo
2012-10-01
The paper deals with the bifurcation analysis of a rather simple model describing an automobile negotiating a curve. The mechanical model has two degrees of freedom and the related equations of motion contain the nonlinear tyre characteristics. Bifurcation analysis is adopted as the proper procedure for analysing steady-state cornering. Two independent parameters referring to running conditions, namely steering angle and speed, are varied. Ten different combinations of front and rear tyre characteristics (featuring understeer or oversteer automobiles) are considered for the bifurcation analysis. Many different dynamical behaviours of the model are obtained by slightly varying the parameters describing the tyre characteristics. Both simple and extremely complex bifurcations may occur. Homoclinic bifurcations, stable and unstable limit cycles (of considerable amplitude) are found, giving a sound and ultimate interpretation to some actual (rare but very dangerous) dynamic behaviours of automobiles, as reported by professional drivers. The presented results are cross-validated by exploiting handling diagram theory. The knowledge of the derived set of bifurcations is dramatically important to fully understand the actual vehicle yaw motions occurring while running on an even surface. Such a knowledge is a pre-requisite for robustly designing the chassis and for enhancing the active safety of vehicles.
1998-09-01
Publishing Company DIFFUSION PARAMETER CONTROL OF SPATIOTEMPORAL CHAOS RAUL MONTAGNE* Instituto de Fisica, Facultad de Ciencias & Facultad de Ingenieria ...aerospace, chemical, civil, computer, information, mechanical, software , telecommunication, etc.) the local and global manifestations of Chaos and Bifurcation...LASERS BY FEEDBACK AND NONFEEDBACK METHODS PIERRE GLORIEUX Laboratoire de Spectroscopie Hertzienne, URA CNRS 249, Centre d’Etudes et Recherches sur les
Stability, bifurcation and a new chaos in the logistic differential equation with delay
International Nuclear Information System (INIS)
Jiang Minghui; Shen Yi; Jian Jigui; Liao Xiaoxin
2006-01-01
This Letter is concerned with bifurcation and chaos in the logistic delay differential equation with a parameter r. The linear stability of the logistic equation is investigated by analyzing the associated characteristic transcendental equation. Based on the normal form approach and the center manifold theory, the formula for determining the direction of Hopf bifurcation and the stability of bifurcation periodic solution in the first bifurcation values is obtained. By theoretical analysis and numerical simulation, we found a new chaos in the logistic delay differential equation
Potential Performance Theory (PPT): A General Theory of Task Performance Applied to Morality
Trafimow, David; Rice, Stephen
2008-01-01
People can use a variety of different strategies to perform tasks and these strategies all have two characteristics in common. First, they can be evaluated in comparison with either an absolute or a relative standard. Second, they can be used at varying levels of consistency. In the present article, the authors develop a general theory of task…
Dynamics and bifurcations of travelling wave solutions of R(m, n ...
Indian Academy of Sciences (India)
We shall now concentrate on the travelling wave solutions to the R(m, n) equations under consideration. By using the bifurcation theory and methods of planar dynamical systems, we obtain the global dynamical behavior and bifurcations of the travelling wave solutions of (1.2). Substituting the travelling wave transformation ...
Bifurcation Analysis of Gene Propagation Model Governed by Reaction-Diffusion Equations
Directory of Open Access Journals (Sweden)
Guichen Lu
2016-01-01
Full Text Available We present a theoretical analysis of the attractor bifurcation for gene propagation model governed by reaction-diffusion equations. We investigate the dynamical transition problems of the model under the homogeneous boundary conditions. By using the dynamical transition theory, we give a complete characterization of the bifurcated objects in terms of the biological parameters of the problem.
On the Nature of Applied Linguistics: Theory and Practice Relationships from a Critical Perspective
Sánchez, William
2007-01-01
This article explores the relationships between Applied Linguistics and other related disciplines concerning language use and language teaching issues. It seeks to trace the changes in the view of the relationship between theory and practice in Applied Linguistics, to explain the reason for those changes, and to discuss the implications for…
Applying Differential Coercion and Social Support Theory to Intimate Partner Violence.
Zavala, Egbert; Kurtz, Don L
2017-09-01
A review of the current body of literature on intimate partner violence (IPV) shows that the most common theories used to explain this public health issue are social learning theory, a general theory of crime, general strain theory, or a combination of these perspectives. Other criminological theories have received less empirical attention. Therefore, the purpose of this study is to apply Differential Coercion and Social Support (DCSS) theory to test its capability to explain IPV. Data collected from two public universities ( N = 492) shows that three out of four measures of coercion (i.e., physical abuse, emotional abuse, and anticipated strain) predicted IPV perpetration, whereas social support was not found to be significant. Only two social-psychological deficits (anger and self-control) were found to be positive and significant in predicting IPV. Results, as well as the study's limitations and suggestions for future research, are discussed.
Riddling bifurcation and interstellar journeys
International Nuclear Information System (INIS)
Kapitaniak, Tomasz
2005-01-01
We show that riddling bifurcation which is characteristic for low-dimensional attractors embedded in higher-dimensional phase space can give physical mechanism explaining interstellar journeys described in science-fiction literature
Applying circular economy innovation theory in business process modeling and analysis
Popa, V.; Popa, L.
2017-08-01
The overall aim of this paper is to develop a new conceptual framework for business process modeling and analysis using circular economy innovative theory as a source for business knowledge management. The last part of the paper presents an author’s proposed basic structure for a new business models applying circular economy innovation theories. For people working on new innovative business models in the field of the circular economy this paper provides new ideas for clustering their concepts.
Multisided media markets: Applying the theory of multisided markets to media markets
Lindstädt, Nadine
2009-01-01
Media markets recently have been identified as multisided markets. The application of the theory of multisided markets provides a better understanding of such markets. It enriched the hitherto economic approach and led to new insights and perspectives especially for the antitrust authorities when evaluating competition constraints and mergers. This paper reviews the theory of multisided markets and subsequently applies it to media markets. Finally the paper draws attention to the new perspect...
Numerical Hopf bifurcation of Runge-Kutta methods for a class of delay differential equations
International Nuclear Information System (INIS)
Wang Qiubao; Li Dongsong; Liu, M.Z.
2009-01-01
In this paper, we consider the discretization of parameter-dependent delay differential equation of the form y ' (t)=f(y(t),y(t-1),τ),τ≥0,y element of R d . It is shown that if the delay differential equation undergoes a Hopf bifurcation at τ=τ * , then the discrete scheme undergoes a Hopf bifurcation at τ(h)=τ * +O(h p ) for sufficiently small step size h, where p≥1 is the order of the Runge-Kutta method applied. The direction of numerical Hopf bifurcation and stability of bifurcating invariant curve are the same as that of delay differential equation.
Bifurcation analysis can unify ecological and evolutionary aspects of ecosystems.
Troost, T.A.; Kooi, B.W.; Kooijman, S.A.L.M.
2007-01-01
Bifurcation theory is commonly used to study the dynamical behaviour of ecosystems. It involves the analysis of points in the parameter space where the stability of the system changes qualitatively. Generally, such changes are related only to changes in environmental parameters, while the organism's
Nonintegrability of the unfolding of the fold-Hopf bifurcation
Yagasaki, Kazuyuki
2018-02-01
We consider the unfolding of the codimension-two fold-Hopf bifurcation and prove its meromorphic nonintegrability in the meaning of Bogoyavlenskij for almost all parameter values. Our proof is based on a generalized version of the Morales-Ramis-Simó theory for non-Hamiltonian systems and related variational equations up to second order are used.
Coupled channel theory of pion--deuteron reaction applied to threshold scattering
International Nuclear Information System (INIS)
Mizutani, T.; Koltun, D.S.
1977-01-01
Scattering and absorption of pions by a nuclear target are treated together in a coupled channel theory. The theory is developed explicitly for the problem of pion scattering and absorption by a deuteron. The equations are presented in terms of the integral equations of three-body scattering theory. The method is then applied in an approximate from to calculate the contribution of pion absorption to the scattering length for pion--deuteron scattering. The sensitivity of the calculated results to the model assumptions and approximations is investigated
Quantitative angiography methods for bifurcation lesions
DEFF Research Database (Denmark)
Collet, Carlos; Onuma, Yoshinobu; Cavalcante, Rafael
2017-01-01
Bifurcation lesions represent one of the most challenging lesion subsets in interventional cardiology. The European Bifurcation Club (EBC) is an academic consortium whose goal has been to assess and recommend the appropriate strategies to manage bifurcation lesions. The quantitative coronary...... angiography (QCA) methods for the evaluation of bifurcation lesions have been subject to extensive research. Single-vessel QCA has been shown to be inaccurate for the assessment of bifurcation lesion dimensions. For this reason, dedicated bifurcation software has been developed and validated. These software...
Circular waveguide bifurcation for asymmetric modes
Schilling, H. W.; Collin, R. E.
1984-12-01
An analytical solution for a circular waveguide bifurcation with incident TE(11)- and TM(11)-modes is presented using the residue calculus method. It is shown how the coupling between the TE(1n)- and TM(1n)-modes can be taken into account by expressing the coupling factor as a contour integral, which is the key step enabling the residue calculus method to be applied. Graphical results for the scattering matrix parameters of the junction are given for a range of waveguide radii of interest in the design of dual-mode coaxial prime focus feeds for paraboloidal antennas.
Double Hopf bifurcation in delay differential equations
Directory of Open Access Journals (Sweden)
Redouane Qesmi
2014-07-01
Full Text Available The paper addresses the computation of elements of double Hopf bifurcation for retarded functional differential equations (FDEs with parameters. We present an efficient method for computing, simultaneously, the coefficients of center manifolds and normal forms, in terms of the original FDEs, associated with the double Hopf singularity up to an arbitrary order. Finally, we apply our results to a nonlinear model with periodic delay. This shows the applicability of the methodology in the study of delay models arising in either natural or technological problems.
Bifurcations and feedback control of a stage-structure exploited prey ...
African Journals Online (AJOL)
user
predator system with differential algebraic equations. The criterion ...... research interests include dynamical systems, stability and bifurcation theory, population dynamics, mathematical modeling in ecology and epidemiology, management and ...
Magneto-elastic dynamics and bifurcation of rotating annular plate*
International Nuclear Information System (INIS)
Hu Yu-Da; Piao Jiang-Min; Li Wen-Qiang
2017-01-01
In this paper, magneto-elastic dynamic behavior, bifurcation, and chaos of a rotating annular thin plate with various boundary conditions are investigated. Based on the thin plate theory and the Maxwell equations, the magneto-elastic dynamic equations of rotating annular plate are derived by means of Hamilton’s principle. Bessel function as a mode shape function and the Galerkin method are used to achieve the transverse vibration differential equation of the rotating annular plate with different boundary conditions. By numerical analysis, the bifurcation diagrams with magnetic induction, amplitude and frequency of transverse excitation force as the control parameters are respectively plotted under different boundary conditions such as clamped supported sides, simply supported sides, and clamped-one-side combined with simply-anotherside. Poincaré maps, time history charts, power spectrum charts, and phase diagrams are obtained under certain conditions, and the influence of the bifurcation parameters on the bifurcation and chaos of the system is discussed. The results show that the motion of the system is a complicated and repeated process from multi-periodic motion to quasi-period motion to chaotic motion, which is accompanied by intermittent chaos, when the bifurcation parameters change. If the amplitude of transverse excitation force is bigger or magnetic induction intensity is smaller or boundary constraints level is lower, the system can be more prone to chaos. (paper)
Perkins, Matthew B; Jensen, Peter S; Jaccard, James; Gollwitzer, Peter; Oettingen, Gabriele; Pappadopulos, Elizabeth; Hoagwood, Kimberly E
2007-03-01
Despite major recent research advances, large gaps exist between accepted mental health knowledge and clinicians' real-world practices. Although hundreds of studies have successfully utilized basic behavioral science theories to understand, predict, and change patients' health behaviors, the extent to which these theories-most notably the theory of reasoned action (TRA) and its extension, the theory of planned behavior (TPB)-have been applied to understand and change clinician behavior is unclear. This article reviews the application of theory-driven approaches to understanding and changing clinician behaviors. MEDLINE and PsycINFO databases were searched, along with bibliographies, textbooks on health behavior or public health, and references from experts, to find article titles that describe theory-driven approaches (TRA or TPB) to understanding and modifying health professionals' behavior. A total of 19 articles that detailed 20 studies described the use of TRA or TPB and clinicians' behavior. Eight articles describe the use of TRA or TPB with physicians, four relate to nurses, three relate to pharmacists, and two relate to health workers. Only two articles applied TRA or TPB to mental health clinicians. The body of work shows that different constructs of TRA or TPB predict intentions and behavior among different groups of clinicians and for different behaviors and guidelines. The number of studies on this topic is extremely limited, but they offer a rationale and a direction for future research as well as a theoretical basis for increasing the specificity and efficiency of clinician-targeted interventions.
Kubota, Ryuko
2016-01-01
In applied linguistics and language education, an increased focus has been placed on plurality and hybridity to challenge monolingualism, the native speaker norm, and the modernist view of language and language use as unitary and bounded. The multi/plural turn parallels postcolonial theory in that they both support hybridity and fluidity while…
Lin, Su-ching; Wu, Ming-sui
2016-01-01
This study was the first year of a two-year project which applied a program theory-driven approach to evaluating the impact of teachers' professional development interventions on students' learning by using a mix of methods, qualitative inquiry, and quasi-experimental design. The current study was to show the results of using the method of…
ICOM-ICTOP 14 October 2015 Workshop : Applying Global Theory to Local Practice
Ariese, C.E.; Con, Aguilar E.O.; Martin, J.A.
2015-01-01
This workshop is connected to the presentation ‘Transforming global theory to local practice: Case studies from museums and education in the Caribbean’ and provides a practical and creative exercise for participants. The objective of the workshop is to support participants in exploring how to apply
Unlocking Hospitality Managers Career Transitions through Applying Schein's Career Anchors Theory
McGuire, David; Polla, Giovana; Heidl, Britta
2017-01-01
Purpose: This paper seeks to unlock the career transitions of hospitality managers through applying Schein's career anchors theory. It seeks to understand how Schein's Career Anchors help explain the career transitions of managers in the Scottish hospitality industry. Design/methodology/approach: The paper adopts a non-sequential multi-method…
SOLUTION TO THE PROBLEMS OF APPLIED MECHANICS USING THE SIMILARITY THEORY AND DIMENSIONAL ANALYSIS
Directory of Open Access Journals (Sweden)
Dzhinchvelashvili Guram Avtandilovich
2016-06-01
Full Text Available In the present work the author announces a book of Professor G.S. Vardanyan in which the bases of similarity theory and dimensional analysis are systematically set forward. It discusses the possibilities of these methods and their application in solving not only fundamental problems of solid mechanics, but also applied tasks, in particular, complicated problems of engineering seismology.
Applying Social Cognitive Theory to Academic Advising to Assess Student Learning Outcomes
Erlich, Richard J.; Russ-Eft, Darlene
2011-01-01
Review of social cognitive theory constructs of self-efficacy and self-regulated learning is applied to academic advising for the purposes of assessing student learning. A brief overview of the history of student learning outcomes in higher education is followed by an explanation of self-efficacy and self-regulated learning constructs and how they…
Pierce instability and bifurcating equilibria
International Nuclear Information System (INIS)
Godfrey, B.B.
1981-01-01
The report investigates the connection between equilibrium bifurcations and occurrence of the Pierce instability. Electrons flowing from one ground plane to a second through an ion background possess a countable infinity of static equilibria, of which only one is uniform and force-free. Degeneracy of the uniform and simplest non-uniform equilibria at a certain ground plan separation marks the onset of the Pierce instability, based on a newly derived dispersion relation appropriate to all the equilibria. For large ground plane separations the uniform equilibrium is unstable and the non-uniform equilibrium is stable, the reverse of their stability properties at small separations. Onset of the Pierce instability at the first bifurcation of equilibria persists in more complicated geometries, providing a general criterion for marginal stability. It seems probable that bifurcation analysis can be a useful tool in the overall study of stable beam generation in diodes and transport in finite cavities
International Nuclear Information System (INIS)
Liu, Yongbao; Wang, Qiang; Xu, Huidong
2017-01-01
The smooth bifurcation and non-smooth grazing bifurcation of periodic solution of three-degree-of-freedom vibro-impact systems with clearance are studied in this paper. Firstly, six-dimensional Poincaré maps are established through choosing suitable Poincaré section and solving periodic solutions of vibro-impact system. Then, as the analytic expressions of all eigenvalues of Jacobi matrix of six-dimensional map are unavailable, the numerical calculations to search for the critical bifurcation values point by point is a laborious job based on the classical critical criterion described by the properties of eigenvalues. To overcome the difficulty from the classical bifurcation criteria, the explicit critical criterion without using eigenvalues calculation of high-dimensional map is applied to determine bifurcation points of Co-dimension-one bifurcations and Co-dimension-two bifurcations, and then local dynamical behaviors of these bifurcations are further analyzed. Finally, the existence of the grazing periodic solution of the vibro-impact system and grazing bifurcation point are analyzed, the discontinuous grazing bifurcation behavior is studied based on the compound normal form map near the grazing point, the discontinuous jumping phenomenon and the co-existing multiple solutions near the grazing bifurcation point are revealed.
Li, Li; Xu, Jian
Time delay is inevitable in unidirectionally coupled drive-free vibratory gyroscope system. The effect of time delay on the gyroscope system is studied in this paper. To this end, amplitude death and Hopf bifurcation induced by small time delay are first investigated by analyzing the related characteristic equation. Then, the direction of Hopf bifurcations and stability of Hopf-bifurcating periodic oscillations are determined by calculating the normal form on the center manifold. Next, spatiotemporal patterns of these Hopf-bifurcating periodic oscillations are analyzed by using the symmetric bifurcation theory of delay differential equations. Finally, it is found that numerical simulations agree with the associated analytic results. These phenomena could be induced although time delay is very small. Therefore, it is shown that time delay is an important factor which influences the sensitivity and accuracy of the gyroscope system and cannot be neglected during the design and manufacture.
Doyle, Laurance R.; McCowan, Brenda; Hanser, Sean F.
2002-01-01
Information theory allows a quantification of the complexity of a given signaling system. We are applying information theory to dolphin whistle vocalizations, humpback whale songs, squirrel monkey chuck calls, and several other animal communication systems' in order to develop a quantitative and objective way to compare inter species communication systems' complexity. Once signaling units have been correctly classified the communication system must obey certain statistical distributions in order to contain complexity whether it is human languages, dolphin whistle vocalizations, or even a system of communication signals received from an extraterrestrial source.
Backward bifurcation and hysteresis in models of recurrent tuberculosis.
Wangari, Isaac Mwangi; Stone, Lewi
2018-01-01
An epidemiological model is presented that provides a comprehensive description of the transmission pathways involved for recurrent tuberculosis (TB), whereby cured individuals can become reinfected. Our main goal is to determine conditions that lead to the appearance of a backward bifurcation. This occurs when an asymptotically stable infection free equilibrium concurrently exists with a stable non-trivial equilibria even though the basic reproduction number R0 is less than unity. Although, some 10-30% cases of TB are recurrent, the role of recurrent TB as far as the formation of backward bifurcation is concerned, is rarely if ever studied. The model used here incorporates progressive primary infection, exogenous reinfection, endogenous reactivation and recurrent TB as transmission mechanisms that contribute to TB progression. Unlike other studies of TB dynamics that make use of frequency dependent transmission rates, our analysis provides exact backward bifurcation threshold conditions without resorting to commonly applied approximations and simplifying assumptions. Exploration of the model through analytical and numerical analysis reveal that recurrent TB is sometimes capable of triggering hysteresis effects which allow TB to persist when R0 < 1 even though there is no backward bifurcation. Furthermore, recurrent TB can independently induce backward bifurcation phenomena if it exceeds a certain threshold.
Bifurcation analysis of nephron pressure and flow regulation
DEFF Research Database (Denmark)
Barfred, Mikael; Mosekilde, Erik; Holstein-Rathlou, N.-H.
1996-01-01
One- and two-dimensional continuation techniques are applied to study the bifurcation structure of a model of renal flow and pressure control. Integrating the main physiological mechanisms by which the individual nephron regulates the incoming blood flow, the model describes the interaction between...... the tubuloglomerular feedback and the response of the afferent arteriole. It is shown how a Hopf bifurcation leads the system to perform self-sustained oscillations if the feedback gain becomes sufficiently strong, and how a further increase of this parameter produces a folded structure of overlapping period...
Crisis bifurcations in plane Poiseuille flow
Zammert, S.; Eckhardt, B.E.
2015-01-01
Many shear flows follow a route to turbulence that has striking similarities to bifurcation scenarios in low-dimensional dynamical systems. Among the bifurcations that appear, crisis bifurcations are important because they cause global transitions between open and closed attractors, or indicate
Stochastic stability and bifurcation in a macroeconomic model
International Nuclear Information System (INIS)
Li Wei; Xu Wei; Zhao Junfeng; Jin Yanfei
2007-01-01
On the basis of the work of Goodwin and Puu, a new business cycle model subject to a stochastically parametric excitation is derived in this paper. At first, we reduce the model to a one-dimensional diffusion process by applying the stochastic averaging method of quasi-nonintegrable Hamiltonian system. Secondly, we utilize the methods of Lyapunov exponent and boundary classification associated with diffusion process respectively to analyze the stochastic stability of the trivial solution of system. The numerical results obtained illustrate that the trivial solution of system must be globally stable if it is locally stable in the state space. Thirdly, we explore the stochastic Hopf bifurcation of the business cycle model according to the qualitative changes in stationary probability density of system response. It is concluded that the stochastic Hopf bifurcation occurs at two critical parametric values. Finally, some explanations are given in a simply way on the potential applications of stochastic stability and bifurcation analysis
Symmetry and Bifurcation in Three Dimensional Elasticity. Part I.
1981-04-01
small. Applying the isotopy theoren for transversal maps (see e.g., Hirsch [19761) to the family . through h0 = k , we conclude that the bifurcation set...cI ,c c 1’ ,.c is hounded uniformly for N > 0 , c sufficiently small. \\pplving the isotopy theorem for transversal mans to the family h. through the
On the analysis of local bifurcation and topological horseshoe of a new 4D hyper-chaotic system
International Nuclear Information System (INIS)
Zhou, Leilei; Chen, Zengqiang; Wang, Zhonglin; Wang, Jiezhi
2016-01-01
Highlights: • A new 4D smooth quadratic autonomous system with complex hyper-chaotic dynamics is presented. • The stability of equilibria is observed near the bifurcation points. • The Hopf bifurcation and pitchfork bifurcation are analyzed by using the center manifold theorem and bifurcation theory. • A horseshoe with two-directional expansions in the 4D hyper-chaotic system has been found, which rigorously proves the existence of hyper-chaos in theory. - Abstract: In this paper, a new four-dimensional (4D) smooth quadratic autonomous system with complex hyper-chaotic dynamics is presented and analyzed. The Lyapunov exponent (LE) spectrum, bifurcation diagram and various phase portraits of the system are provided. The stability, Hopf bifurcation and pitchfork bifurcation of equilibrium point are discussed by using the center manifold theorem and bifurcation theory. Numerical simulation results are consistent with the theoretical analysis. Besides, by combining the topological horseshoe theory with a computer-assisted method of Poincaré maps and utilizing the algorithm for finding horseshoes in 3D hyper-chaotic maps, a horseshoe with two-directional expansions in the 4D hyper-chaotic system is successfully found, which rigorously proves the existence of hyper-chaos in theory.
Homoclinic bifurcation in Chua's circuit
Indian Academy of Sciences (India)
Abstract. We report our experimental observations of the Shil'nikov-type homoclinic chaos in asymmetry-induced Chua's oscillator. The asymmetry plays a crucial role in the related homoclinic bifurcations. The asymmetry is introduced in the circuit by forcing a. DC voltage. For a selected asymmetry, when a system ...
A bifurcation analysis for the Lugiato-Lefever equation
Godey, Cyril
2017-05-01
The Lugiato-Lefever equation is a cubic nonlinear Schrödinger equation, including damping, detuning and driving, which arises as a model in nonlinear optics. We study the existence of stationary waves which are found as solutions of a four-dimensional reversible dynamical system in which the evolutionary variable is the space variable. Relying upon tools from bifurcation theory and normal forms theory, we discuss the codimension 1 bifurcations. We prove the existence of various types of steady solutions, including spatially localized, periodic, or quasi-periodic solutions. Contribution to the Topical Issue: "Theory and Applications of the Lugiato-Lefever Equation", edited by Yanne K. Chembo, Damia Gomila, Mustapha Tlidi, Curtis R. Menyuk.
MacDougall, Colin; Gibbs, Lisa; Clark, Rachel
2014-04-01
The Victorian Country Fire Authority in Australia runs the Community Fireguard (CFG) programme to assist individuals and communities in preparing for fire. The objective of this qualitative research was to understand the impact of CFG groups on their members' fire preparedness and response during the 2009 Australian bushfires. Social connectedness emerged as a strong theme, leading to an analysis of data using social capital theory. The main strength of the CFG programme was that it was driven by innovative community members; however, concerns arose regarding the extent to which the programme covered all vulnerable areas, which led the research team to explore the theory of diffusion of innovation. The article concludes by stepping back from the evaluation and using both applied theories to reflect on broad options for community fire preparedness programmes in general. The exercise produced two contrasting options for principles underlying community fire preparedness programmes. © 2014 The Author(s). Disasters © Overseas Development Institute, 2014.
Bryson, Claire N; Cramer, Robert J; Schmidt, Adam T
2017-08-01
The present article investigates the traumatic brain injury (TBI)-suicide link, assessing whether (a) TBI accounts for variance in suicide risk, and (b) the interpersonal-psychological theory of suicide can be applied to TBI status. Matched case-control procedures applied to archival college student health data identified TBI and non-TBI subsamples (84 total). Individuals with a TBI possessed higher suicide risk than those without. Even accounting for the relative influence of strong suicide risk factors (i.e., depression, perceived burdensomeness, thwarted belongingness, and acquired capability), TBI was robustly associated with suicide risk. TBI history would be valuable to ascertain in assessing suicide risk.
Jalilian, Farzad; Allahverdipour, Hamid; Moeini, Babak; Moghimbeigi, Abbas
2011-01-01
Background: Use of anabolic androgenic steroids (AAS) has been associated with adversephysical and psychiatric effects and it is known as rising problem among youth people. Thisstudy was conducted to evaluate anabolic steroids preventative intervention efficiency amonggym users in Iran and theory of planned behaviour was applied as theoretical framework.Methods: Overall, 120 male gym users participated in this study as intervention and controlgroup. This was a longitudinal randomized pretest ...
Tutorial - applying extreme value theory to characterize food-processing systems
DEFF Research Database (Denmark)
Skou, Peter Bæk; Holroyd, Stephen E.; van der Berg, Franciscus Winfried J
2017-01-01
This tutorial presents extreme value theory (EVT) as an analytical tool in process characterization and shows its potential to describe production performance, eg, across different factories, via reliable estimates of the frequency and scale of extreme events. Two alternative EVT methods...... are discussed: point over threshold and block maxima. We illustrate the theoretical framework for EVT by process data from two different examples from the food-processing industry. Finally, we discuss limitations, decisions, and possibilities when applying EVT for process data....
Stochastic relaxational dynamics applied to finance: towards non-equilibrium option pricing theory
Otto, Matthias
1999-01-01
Non-equilibrium phenomena occur not only in physical world, but also in finance. In this work, stochastic relaxational dynamics (together with path integrals) is applied to option pricing theory. A recently proposed model (by Ilinski et al.) considers fluctuations around this equilibrium state by introducing a relaxational dynamics with random noise for intermediate deviations called ``virtual'' arbitrage returns. In this work, the model is incorporated within a martingale pricing method for ...
The Quantum Mechanics Solver How to Apply Quantum Theory to Modern Physics
Basdevant, Jean-Louis
2006-01-01
The Quantum Mechanics Solver grew from topics which are part of the final examination in quantum theory at the Ecole Polytechnique at Palaiseau near Paris, France. The aim of the text is to guide the student towards applying quantum mechanics to research problems in fields such as atomic and molecular physics, condensed matter physics, and laser physics. Advanced undergraduates and graduate students will find a rich and challenging source for improving their skills in this field.
Directory of Open Access Journals (Sweden)
Zizhen Zhang
2017-01-01
Full Text Available Hopf bifurcation for an SEIRS-V model with delays on the transmission of worms in a wireless sensor network is investigated. We focus on existence of the Hopf bifurcation by regarding the diverse delay as a bifurcation parameter. The results show that propagation of worms in the wireless sensor network can be controlled when the delay is suitably small under some certain conditions. Then, we study properties of the Hopf bifurcation by using the normal form theory and center manifold theorem. Finally, we give a numerical example to support the theoretical results.
International Nuclear Information System (INIS)
Ding Xiaohua; Su Huan; Liu Mingzhu
2008-01-01
The paper analyzes a discrete second-order, nonlinear delay differential equation with negative feedback. The characteristic equation of linear stability is solved, as a function of two parameters describing the strength of the feedback and the damping in the autonomous system. The existence of local Hopf bifurcations is investigated, and the direction and stability of periodic solutions bifurcating from the Hopf bifurcation of the discrete model are determined by the Hopf bifurcation theory of discrete system. Finally, some numerical simulations are performed to illustrate the analytical results found
Wang, Zhen; Wang, Xiaohong; Li, Yuxia; Huang, Xia
2017-12-01
In this paper, the problems of stability and Hopf bifurcation in a class of fractional-order complex-valued single neuron model with time delay are addressed. With the help of the stability theory of fractional-order differential equations and Laplace transforms, several new sufficient conditions, which ensure the stability of the system are derived. Taking the time delay as the bifurcation parameter, Hopf bifurcation is investigated and the critical value of the time delay for the occurrence of Hopf bifurcation is determined. Finally, two representative numerical examples are given to show the effectiveness of the theoretical results.
Directory of Open Access Journals (Sweden)
Yi Zhang
2014-01-01
Full Text Available The objective of this paper is to study systematically the bifurcation and control of a single-species fish population logistic model with the invasion of alien species based on the theory of singular system and bifurcation. It regards Spartina anglica as an invasive species, which invades the fisheries and aquaculture. Firstly, the stabilities of equilibria in this model are discussed. Moreover, the sufficient conditions for existence of the trans-critical bifurcation and the singularity induced bifurcation are obtained. Secondly, the state feedback controller is designed to eliminate the unexpected singularity induced bifurcation by combining harvested effort with the purification capacity. It obviously inhibits the switch of population and makes the system stable. Finally, the numerical simulation is proposed to show the practical significance of the bifurcation and control from the biological point of view.
Shachak, Aviv; Ophir, Ron; Rubin, Eitan
2005-01-01
The need to support bioinformatics training has been widely recognized by scientists, industry, and government institutions. However, the discussion of instructional methods for teaching bioinformatics is only beginning. Here we report on a systematic attempt to design two bioinformatics workshops for graduate biology students on the basis of Gagne's Conditions of Learning instructional design theory. This theory, although first published in the early 1970s, is still fundamental in instructional design and instructional technology. First, top-level as well as prerequisite learning objectives for a microarray analysis workshop and a primer design workshop were defined. Then a hierarchy of objectives for each workshop was created. Hands-on tutorials were designed to meet these objectives. Finally, events of learning proposed by Gagne's theory were incorporated into the hands-on tutorials. The resultant manuals were tested on a small number of trainees, revised, and applied in 1-day bioinformatics workshops. Based on this experience and on observations made during the workshops, we conclude that Gagne's Conditions of Learning instructional design theory provides a useful framework for developing bioinformatics training, but may not be optimal as a method for teaching it.
Bifurcation routes and economic stability
Czech Academy of Sciences Publication Activity Database
Vošvrda, Miloslav
2001-01-01
Roč. 8, č. 14 (2001), s. 43-59 ISSN 1212-074X R&D Projects: GA ČR GA402/00/0439; GA ČR GA402/01/0034; GA ČR GA402/01/0539 Institutional research plan: AV0Z1075907 Keywords : macroeconomic stability * foreign investment phenomenon * the Hopf bifurcation Subject RIV: AH - Economics
Control Theory Concepts Applied to Retail Supply Chain: A System Dynamics Modeling Environment Study
Directory of Open Access Journals (Sweden)
Balaji Janamanchi
2013-01-01
Full Text Available Control theory concepts have been long used to successfully manage and optimize complex systems. Using system dynamics (SD modeling methodology, which is continuous deterministic simulation modeling methodology, we apply control theory concepts to develop a suitable performance functional (or objective function that optimizes the performance of a retail supply chain. The focus is to develop insights for inventory management to prevent stock-outs and unfilled orders and to fill customer orders at the lowest possible cost to supply chain partners under different scenarios, in a two-player supplier-retailer supply chain. Moderate levels of inventory, defining appropriate performance functional, appear to be crucial in choosing the right policies for managing retail supply chain systems. The study also demonstrated how multiple objectives can be combined in a single performance functional (or objective function by carefully assigning suitable weights to the components of objectives based on their priority and the existence of possible trade off opportunities.
Prevention of sexual harassment in the medical setting applying Inoculation Theory.
Matusitz, Jonathan; Breen, Gerald Mark
2005-01-01
This paper is an examination of how Inoculation Theory can be applied in the prevention of sexual harassment in the medical setting. The basic tenet of the theory is the study of the processes through which we withstand and oppose attitude transformation during social interactions that may influence or change our attitudes. More importantly, this paper analyzes sexual harassment as a pervasive phenomenon in the medical setting. As such, it defines what sexual harassment is, explains the prevalence of sexual harassment between the physician and the patient, describes some of the general studies conducted in medical settings, provides a case scenario of doctor-patient sexual harassment, and identifies some key consequences to doctors, patients, and society.
Directory of Open Access Journals (Sweden)
Tumpal Sihombing
2013-01-01
Full Text Available The world is entering the era of recession when the trend is bearish and market is not so favorable. The capital markets in every major country were experiencing great amount of loss and people suffered in their investment. The Jakarta Composite Index (JCI has shown a great downturn for the past one year but the trend bearish year of the JCI. Therefore, rational investors should consider restructuring their portfolio to set bigger proportion in bonds and cash instead of stocks. Investors can apply modern portfolio theory by Harry Markowitz to find the optimum asset allocation for their portfolio. Higher return is always associated with higher risk. This study shows investors how to find out the lowest risk of a portfolio investment by providing them with several structures of portfolio weighting. By this way, investor can compare and make the decision based on risk-return consideration and opportunity cost as well. Keywords: Modern portfolio theory, Monte Carlo, linear programming
ACTIVITY THEORY APPLIED AT CHANNEL EXPANSIONS IN SMALL AND MEDIUM ENTERPRISES
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Siw Lundqvist
2017-06-01
Full Text Available Today’s commonly carried out channel expansions of commerce could be both costly and problematic to manage. Especially for small and medium-sized enterprises (SMEs that often suffer from a lack of digital competence, time and monetary resources in generally. Still, these transitions would be necessary to carry out because of customer demands and expectations concerning 24/7 availability, and access to digital commerce alternatives. Scarce resources are important reasons to search for how to carry out channel expansions with minimized problems. Activity theory (AT focuses on the whole in order to detect problems that hinder successful outcomes. Hence, this theory was applied to prior findings, from a project about SME’s channel expansions, highlighting several problems that could appear during these activities. Implications for research foremost involve issues connected to the use of AT; implications for practice particularly concern if and how AT could be used to support channel broadening activities.
Valente, Thomas W; Pitts, Stephanie R
2017-03-20
The use of social network theory and analysis methods as applied to public health has expanded greatly in the past decade, yielding a significant academic literature that spans almost every conceivable health issue. This review identifies several important theoretical challenges that confront the field but also provides opportunities for new research. These challenges include (a) measuring network influences, (b) identifying appropriate influence mechanisms, (c) the impact of social media and computerized communications, (d) the role of networks in evaluating public health interventions, and (e) ethics. Next steps for the field are outlined and the need for funding is emphasized. Recently developed network analysis techniques, technological innovations in communication, and changes in theoretical perspectives to include a focus on social and environmental behavioral influences have created opportunities for new theory and ever broader application of social networks to public health topics.
Applying the theory of planned behavior to promotion of whole-grain foods by dietitians.
Chase, Kellie; Reicks, Marla; Jones, Julie Miller
2003-12-01
The objective of this preliminary study was to apply the theory of planned behavior to explain dietitians' intentions to promote whole-grain foods. Surveys were mailed to a random national sample of registered dietitians to assess knowledge and attitudinal, normative, and control beliefs regarding intention to promote whole-grain foods, with a 39% return rate (n=776, with 628 usable surveys from those working in direct patient care). About half of the respondents had a master's degree, and 58% had substantial experience in the dietetics field. The theory of planned behavior explained intention to promote whole grains to a moderate extent (df=3, F=74.5, R(2)=0.278, Pconsume more whole-grain foods. Continuing education for dietitians should use strategies that enhance self-efficacy regarding ability to promote whole-grain foods.
Bifurcation of volcanic plumes in a crosswind
Ernst, Gerald G. J.; Davis, John P.; Sparks, R. Stephen J.
1994-08-01
Bent-over buoyant jets distorted by a crosscurrent develop a vortex pair structure and can bifurcate to produce two distinct lobes which diverge from one another downwind. The region downwind of the source between the lobes has relatively low proportions of discharged fluid. Factors invoked by previous workers to cause or enhance bifurcation include buoyancy, release of latent heat at the plume edge by evaporating water droplets, geometry and orientation of the source, and the encounter with a density interface on the rising path of the plume. We suggest that the pressure distribution around the vortex pair of a rising plume may initially trigger bifurcation. We also report new experimental observations confirming that bifurcation becomes stronger for stronger bent-over plumes, identifying that bifurcation can also occur for straight-edged plumes but gradually disappears for stronger plumes which form a gravity current at their final level and spread for a significant distance against the current. Observations from satellites and the ground are reviewed and confirm that volcanic plumes can show bifurcation and a large range of bifurcation angles. Many of the bifurcating plumes spread out at the tropopause level and suggest the tropopause may act on the plumes as a density interface enhancing bifurcation. Even for quite moderate bifurcation angles, the two plume lobes become rapidly separated downwind by distances of tens of kilometers. Such bifurcating plumes drifting apart can only result in bilobate tephra fall deposits. The tephra fall deposit from the 16 km elevation, SE spreading, bifurcating volcanic plume erupted on 15 May 1981 from Mt Pagan was sampled by previous workers and clearly displayed bilobate characteristics. Examples of bilobate tephra fall deposits are reviewed and their origin briefly discussed. Bilobate deposits are common and may result from many causes. Plume bifurcation should be considered one of the possible mechanisms which can account
Stability and Hopf bifurcation in a delayed competitive web sites model
International Nuclear Information System (INIS)
Xiao Min; Cao Jinde
2006-01-01
The delayed differential equations modeling competitive web sites, based on the Lotka-Volterra competition equations, are considered. Firstly, the linear stability is investigated. It is found that there is a stability switch for time delay, and Hopf bifurcation occurs when time delay crosses through a critical value. Then the direction and stability of the bifurcated periodic solutions are determined, using the normal form theory and the center manifold reduction. Finally, some numerical simulations are carried out to illustrate the results found
Bifurcation in Z2-symmetry quadratic polynomial systems with delay
International Nuclear Information System (INIS)
Zhang Chunrui; Zheng Baodong
2009-01-01
Z 2 -symmetry systems are considered. Firstly the general forms of Z 2 -symmetry quadratic polynomial system are given, and then a three-dimensional Z 2 equivariant system is considered, which describes the relations of two predator species for a single prey species. Finally, the explicit formulas for determining the Fold and Hopf bifurcations are obtained by using the normal form theory and center manifold argument.
Set Theory Applied to the Mathematical Characterization of HLA Class II Binding Peptides
Directory of Open Access Journals (Sweden)
Javier Rodríguez Velásquez, MD, esp.1
2008-04-01
Full Text Available Antigen presentation contains the molecularbasis for antigenic identification and immuneresponses. The set theory and experimental datawere used in order to develop an union core regionmathematic characterization through the definitionof 8 laws associated to HLA class II binding.The laws were applied to 4 promiscuous peptides,25 natural peptides sequences of core region: 13binding peptides and 12 no binding peptides; and19 synthetic peptides looking to differentiate peptides.Only one peptide was not rightly characterized.This methodology may be used to choose keypeptides in the development of vaccine.
Mazuruk, Konstantin; Grugel, Richard N.
2003-01-01
A magnetohydrodynamic model that examines the effect of rotating an electrically conducting cylinder with a uniform external magnetic field applied orthogonal to its axis is presented. Noting a simple geometry, it can be classified as a fundamental dynamo problem. For the case of an infinitely long cylinder, an analytical solution is obtained and analyzed in detail. A semi-analytical model was developed that considers a finite cylinder. Experimental data from a spinning brass wheel in the presence of Earth's magnetic field were compared to the proposed theory and found to fit well.
The Bayesian statistical decision theory applied to the optimization of generating set maintenance
International Nuclear Information System (INIS)
Procaccia, H.; Cordier, R.; Muller, S.
1994-11-01
The difficulty in RCM methodology is the allocation of a new periodicity of preventive maintenance on one equipment when a critical failure has been identified: until now this new allocation has been based on the engineer's judgment, and one must wait for a full cycle of feedback experience before to validate it. Statistical decision theory could be a more rational alternative for the optimization of preventive maintenance periodicity. This methodology has been applied to inspection and maintenance optimization of cylinders of diesel generator engines of 900 MW nuclear plants, and has shown that previous preventive maintenance periodicity can be extended. (authors). 8 refs., 5 figs
Applied Physics of Carbon Nanotubes Fundamentals of Theory, Optics and Transport Devices
Rotkin, Slava V
2005-01-01
The book describes the state-of-the-art in fundamental, applied and device physics of nanotubes, including fabrication, manipulation and characterization for device applications; optics of nanotubes; transport and electromechanical devices and fundamentals of theory for applications. This information is critical to the field of nanoscience since nanotubes have the potential to become a very significant electronic material for decades to come. The book will benefit all all readers interested in the application of nanotubes, either in their theoretical foundations or in newly developed characterization tools that may enable practical device fabrication.
Transport Bifurcation in a Rotating Tokamak Plasma
International Nuclear Information System (INIS)
Highcock, E. G.; Barnes, M.; Schekochihin, A. A.; Parra, F. I.; Roach, C. M.; Cowley, S. C.
2010-01-01
The effect of flow shear on turbulent transport in tokamaks is studied numerically in the experimentally relevant limit of zero magnetic shear. It is found that the plasma is linearly stable for all nonzero flow shear values, but that subcritical turbulence can be sustained nonlinearly at a wide range of temperature gradients. Flow shear increases the nonlinear temperature gradient threshold for turbulence but also increases the sensitivity of the heat flux to changes in the temperature gradient, except over a small range near the threshold where the sensitivity is decreased. A bifurcation in the equilibrium gradients is found: for a given input of heat, it is possible, by varying the applied torque, to trigger a transition to significantly higher temperature and flow gradients.
Cressey’s fraud triangle (1953 and agency theory: study applied to brazilian banking institutions
Directory of Open Access Journals (Sweden)
Michele Rílany Rodrigues Machado
2017-08-01
Full Text Available This research examined if Cressey’s (1953 fraud triangle and the agency theory, jointly, enables investigate corporate fraud occurrence in Brazilian banking institutions. It was formulated six research hypotheses were segregated in fraud triangle – pressure, opportunity and rationalization – and measured by variables taken from the agency theory, criminology and empirical papers on corporate fraud. The identification of probability of fraud occurrence was operationalized from multinomial logistic model, applied to data of 44 banking, for the period between January 2001 and December 2012. For element pressure, hypotheses No. 01 was confirmed, since this showed that the lower an institution’s previous performance, the greater probability there is of fraudulent events occurring in the future. In the element of opportunity, the hypothesis No. 03 was confirmed, which showed that low corporate governance indicators increased the possibility of fraud occurrences. In rationalization element, the hypothesis No. 08 was confirmed, therefore, the predominance of women in management reduces the probability of fraud. We thereby conclude that Cressey’s Triangle, when combined with the theory of agency is an appropriate research instrument to use when carrying out an investigation into corporate fraud occurrence in banking institutions.
Shaw, Jennifer
2016-02-01
The Human Genome Archive Project (HGAP) aimed to preserve the documentary heritage of the UK's contribution to the Human Genome Project (HGP) by using archival theory to develop a suitable methodology for capturing the results of modern, collaborative science. After assessing past projects and different archival theories, the HGAP used an approach based on the theory of documentation strategy to try to capture the records of a scientific project that had an influence beyond the purely scientific sphere. The HGAP was an archival survey that ran for two years. It led to ninety scientists being contacted and has, so far, led to six collections being deposited in the Wellcome Library, with additional collections being deposited in other UK repositories. In applying documentation strategy the HGAP was attempting to move away from traditional archival approaches to science, which have generally focused on retired Nobel Prize winners. It has been partially successful in this aim, having managed to secure collections from people who are not 'big names', but who made an important contribution to the HGP. However, the attempt to redress the gender imbalance in scientific collections and to improve record-keeping in scientific organisations has continued to be difficult to achieve. Copyright © 2015 The Author. Published by Elsevier Ltd.. All rights reserved.
APPLYING THE APOS THEORY TO IMPROVE STUDENTS ABILITY TO PROVE IN ELEMENTARY ABSTRACT ALGEBRA
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I Made Arnawa
2007-04-01
Full Text Available This study is a quasi-experimental nonrandomized pretest-posttest control group design. The experiment group is treated by APOS theory instruction (APOS,that implements four characteristics of APOS theory, (1 mathematical knowledge was constructed through mental construction: actions, processes, objects, and organizing these in schemas, (2 using computer, (3 using cooperative learning groups, and (4 using ACE teaching cycle (activities, class discussion, and exercise. The control group is treated by conventional/traditional mathematics instruction (TRAD. The main purpose of this study is to analyze about achievement in proof. 180 students from two different universities (two classes at the Department of Mathematics UNAND and two classes atthe Department of Mathematics Education UNP PADANG were engaged as the research subjects. Based on the result of data analysis, the main result of this study is that the proof ability of students' in the APOS group is significantly better than student in TRAD group, so it is strongly suggested to apply APOS theory in Abstract Algebra course.
Fujita, Masahiko
2013-06-01
A new supervised learning theory is proposed for a hierarchical neural network with a single hidden layer of threshold units, which can approximate any continuous transformation, and applied to a cerebellar function to suppress the end-point variability of saccades. In motor systems, feedback control can reduce noise effects if the noise is added in a pathway from a motor center to a peripheral effector; however, it cannot reduce noise effects if the noise is generated in the motor center itself: a new control scheme is necessary for such noise. The cerebellar cortex is well known as a supervised learning system, and a novel theory of cerebellar cortical function developed in this study can explain the capability of the cerebellum to feedforwardly reduce noise effects, such as end-point variability of saccades. This theory assumes that a Golgi-granule cell system can encode the strength of a mossy fiber input as the state of neuronal activity of parallel fibers. By combining these parallel fiber signals with appropriate connection weights to produce a Purkinje cell output, an arbitrary continuous input-output relationship can be obtained. By incorporating such flexible computation and learning ability in a process of saccadic gain adaptation, a new control scheme in which the cerebellar cortex feedforwardly suppresses the end-point variability when it detects a variation in saccadic commands can be devised. Computer simulation confirmed the efficiency of such learning and showed a reduction in the variability of saccadic end points, similar to results obtained from experimental data.
Energy Technology Data Exchange (ETDEWEB)
Hyman, J.; Beyer, W.; Louck, J.; Metropolis, N.
1996-07-01
This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Group theoretical methods are a powerful tool both in their applications to mathematics and to physics. The broad goal of this project was to use such methods to develop the implications of group (symmetry) structures underlying models of physical systems, as well as to broaden the understanding of simple models of chaotic systems. The main thrust was to develop further the complex mathematics that enters into many-particle quantum systems with special emphasis on the new directions in applied mathematics that have emerged and continue to surface in these studies. In this area, significant advances in understanding the role of SU(2) 3nj-coefficients in SU(3) theory have been made and in using combinatoric techniques in the study of generalized Schur functions, discovered during this project. In the context of chaos, the study of maps of the interval and the associated theory of words has led to significant discoveries in Galois group theory, to the classification of fixed points, and to the solution of a problem in the classification of DNA sequences.
Clausius entropy for arbitrary bifurcate null surfaces
International Nuclear Information System (INIS)
Baccetti, Valentina; Visser, Matt
2014-01-01
Jacobson’s thermodynamic derivation of the Einstein equations was originally applied only to local Rindler horizons. But at least some parts of that construction can usefully be extended to give meaningful results for arbitrary bifurcate null surfaces. As presaged in Jacobson’s original article, this more general construction sharply brings into focus the questions: is entropy objectively ‘real’? Or is entropy in some sense subjective and observer-dependent? These innocent questions open a Pandora’s box of often inconclusive debate. A consensus opinion, though certainly not universally held, seems to be that Clausius entropy (thermodynamic entropy, defined via a Clausius relation dS=đQ/T) should be objectively real, but that the ontological status of statistical entropy (Shannon or von Neumann entropy) is much more ambiguous, and much more likely to be observer-dependent. This question is particularly pressing when it comes to understanding Bekenstein entropy (black hole entropy). To perhaps further add to the confusion, we shall argue that even the Clausius entropy can often be observer-dependent. In the current article we shall conclusively demonstrate that one can meaningfully assign a notion of Clausius entropy to arbitrary bifurcate null surfaces—effectively defining a ‘virtual Clausius entropy’ for arbitrary ‘virtual (local) causal horizons’. As an application, we see that we can implement a version of the generalized second law (GSL) for this virtual Clausius entropy. This version of GSL can be related to certain (nonstandard) integral variants of the null energy condition. Because the concepts involved are rather subtle, we take some effort in being careful and explicit in developing our framework. In future work we will apply this construction to generalize Jacobson’s derivation of the Einstein equations. (paper)
Applying the Urban Resilience Theory to Flooding on Flood-prone settlements along the Pampanga River
Directory of Open Access Journals (Sweden)
Theresa C Rivera
2015-09-01
Full Text Available By accepting periodic flood as an unavoidable circumstance, urban communities in eastern Pampanga can adapt to flood flows from the Pampanga River better during high-intensity storms by creating a more ecologically-resilient multi-equilibria system of adaptation. A typical solution is to apply engineering solutions to flooding, resulting in a forced state of equilibrium that is ill-adapted to the changing forces of nature. By understanding the dichotomous theory of urban resilience to floods, strategies can be formed to assess and plan a more adaptive flood hazard management framework. To operationalize the theory, an estimation of storm-water and riparian alluvial flow is developed to understand the volumetric capacity of floodwaters natural floodplains need to accommodate flooding. The rational method of computing runoff is applied to the major watershed forming the flood-prone Pampanga River, determining the percentage of floodable area and moving ecological equilibria. This creates a better understanding of the distribution of flood by providing a baseline for the future planning of mitigation and adaptation urban strategies to flooding such as providing vegetated buffer zones, no build zones, and ground to building floor height.
Braided River Evolution and Bifurcation Dynamics During Floods and Low Flow in the Jamuna River
Marra, W. A.; Kleinhans, M. G.; Addink, E.
2010-12-01
River bifurcations have become recognised over the last decade as being critical but poorly understood elements in many channel systems, including braided and anastomosing rivers, fluvial lowland plains and deltas. They control the partitioning of both water and sediment with consequences for the downstream evolution and for river and coastal management. Avulsion studies and bifurcation modelling suggest that symmetrical bifurcations are inherently unstable. However, the simultaneous activity of channels in deltas, anastomosing rivers and large braided rivers such as the Jamuna suggest that symmetrical bifurcations are stable in agreement with sediment transport optimisation theories. These theories are still a matter of debate. Our objective is to understand the stability and evolution of the braid pattern through studying the dynamics of the bifurcations under natural discharge conditions: both during floods and low flow. Using a series of Landsat TM images taken at irregular intervals showing inter-annual variation, we studied the evolution of a large number of bifurcations in the Jamuna river between 1999 and 2004. The images were first classified into water, bare sediment and vegetation. The contiguous water body of the river was then selected and translated into a network description with bifurcations and confluences at the nodes and interconnecting channels. Channel width is a crucial attribute of the network channels as this allows the calculation of bifurcation asymmetry. The key step here is to describe river network evolution by identifying the same node in multiple subsequent images as well as new and abandoned nodes, in order to distinguish migration of bifurcations from avulsion processes. Nodes in two subsequent images were linked through distance and angle of the downstream connected channels. Once identified through time, the changes in node position and the changes in the connected channels can be quantified Along the entire river the well
Vortex Breakdown Generated by off-axis Bifurcation in a cylinder with rotating covers
DEFF Research Database (Denmark)
Bisgaard, Anders; Brøns, Morten; Sørensen, Jens Nørkær
2006-01-01
Vortex breakdown of bubble type is studied for the flow in a cylinder with rotating top and bottom covers. For large ratios of the angular velocities of the covers, we observe numerically that the vortex breakdown bubble in the steady regime may occur through the creation of an off-axis vortex ring....... This scenario does not occur in existing bifurcation theory based on a simple degeneracy in the flow field. We extend the theory to cover a non-simple degeneracy, and derive the associated bifurcation diagrams. We show that the vortex breakdown scenario involving a vortex ring can be explained from this theory...
Hickerson, Stephen C; Fleming, Marc L; Sawant, Ruta V; Ordonez, Nancy D; Sansgiry, Sujit S
The current literature has identified many motivating factors and barriers influencing pharmacy students' decision to apply for residency training. Despite a growing need for residency trained pharmacists to advance the profession, it is not clear why only about one in four pharmacy students decide to pursue a residency, and which of these factors have the most influence on student decision-making. The study examines the factors associated with pharmacy students' intention to apply for a postgraduate residency using the theory of planned behavior (TPB) framework. Second and third-year students from four Texas pharmacy schools were surveyed using an online questionnaire based on the TPB. Descriptive statistics and multiple linear regression analyses were utilized to assess the study objectives. A total of 251 completed responses were received. Attitude, subjective norms (SN), and perceived behavioral control (PBC) were significant predictors of intention to apply for a pharmacy residency (β = 0.32, 0.58, and 0.36, respectively, p social influence of faculty members (β = 0.10, p = 0.003) and family (β = 0.08, p = 0.02); believing financial obligations (β = 0.20, p = 0.006), feeling afraid of the competition and/or not matching (β = 0.24, p make it more difficult to apply for a residency. The TPB model was useful in predicting pharmacy students' intention to apply for a residency, and all TPB constructs were significant predictors. Therefore, interventions that target students' attitude, SN, and PBC may be valuable to increase their intention, especially the specific beliefs identified to significantly predict intention. Future research into methods in which these motivating factors can be encouraged and perceived barriers can be addressed by pharmacy stakeholders will increase interest and participation in residency training. Copyright © 2016 Elsevier Inc. All rights reserved.
Stability and Bifurcation Analysis of a Modified Epidemic Model for Computer Viruses
Directory of Open Access Journals (Sweden)
Chuandong Li
2014-01-01
Full Text Available We extend the three-dimensional SIR model to four-dimensional case and then analyze its dynamical behavior including stability and bifurcation. It is shown that the new model makes a significant improvement to the epidemic model for computer viruses, which is more reasonable than the most existing SIR models. Furthermore, we investigate the stability of the possible equilibrium point and the existence of the Hopf bifurcation with respect to the delay. By analyzing the associated characteristic equation, it is found that Hopf bifurcation occurs when the delay passes through a sequence of critical values. An analytical condition for determining the direction, stability, and other properties of bifurcating periodic solutions is obtained by using the normal form theory and center manifold argument. The obtained results may provide a theoretical foundation to understand the spread of computer viruses and then to minimize virus risks.
Bifurcation and complex dynamics of a discrete-time predator-prey system involving group defense
Directory of Open Access Journals (Sweden)
S. M. Sohel Rana
2015-09-01
Full Text Available In this paper, we investigate the dynamics of a discrete-time predator-prey system involving group defense. The existence and local stability of positive fixed point of the discrete dynamical system is analyzed algebraically. It is shown that the system undergoes a flip bifurcation and a Neimark-Sacker bifurcation in the interior of R+2 by using bifurcation theory. Numerical simulation results not only show the consistence with the theoretical analysis but also display the new and interesting dynamical behaviors, including phase portraits, period-7, 20-orbits, attracting invariant circle, cascade of period-doubling bifurcation from period-20 leading to chaos, quasi-periodic orbits, and sudden disappearance of the chaotic dynamics and attracting chaotic set. The Lyapunov exponents are numerically computed to characterize the complexity of the dynamical behaviors.
Stability and Hopf Bifurcation of a Reaction-Diffusion Neutral Neuron System with Time Delay
Dong, Tao; Xia, Linmao
2017-12-01
In this paper, a type of reaction-diffusion neutral neuron system with time delay under homogeneous Neumann boundary conditions is considered. By constructing a basis of phase space based on the eigenvectors of the corresponding Laplace operator, the characteristic equation of this system is obtained. Then, by selecting time delay and self-feedback strength as the bifurcating parameters respectively, the dynamic behaviors including local stability and Hopf bifurcation near the zero equilibrium point are investigated when the time delay and self-feedback strength vary. Furthermore, the direction of the Hopf bifurcation and the stability of bifurcating periodic solutions are obtained by using the normal form and the center manifold theorem for the corresponding partial differential equation. Finally, two simulation examples are given to verify the theory.
Hopf and Generalized Hopf Bifurcations in a Recurrent Autoimmune Disease Model
Zhang, Wenjing; Yu, Pei
This paper is concerned with bifurcation and stability in an autoimmune model, which was established to study an important phenomenon — blips arising from such models. This model has two equilibrium solutions, disease-free equilibrium and disease equilibrium. The positivity of the solutions of the model and the global stability of the disease-free equilibrium have been proved. In this paper, we particularly focus on Hopf bifurcation which occurs from the disease equilibrium. We present a detailed study on the use of center manifold theory and normal form theory, and derive the normal form associated with Hopf bifurcation, from which the approximate amplitude of the bifurcating limit cycles and their stability conditions are obtained. Particular attention is also paid to the bifurcation of multiple limit cycles arising from generalized Hopf bifurcation, which may yield bistable phenomenon involving equilibrium and oscillating motion. This result may explain some complex dynamical behavior in real biological systems. Numerical simulations are compared with the analytical predictions to show a very good agreement.
Bifurcation and category learning in network models of oscillating cortex
Baird, Bill
1990-06-01
A genetic model of oscillating cortex, which assumes “minimal” coupling justified by known anatomy, is shown to function as an associative memory, using previously developed theory. The network has explicit excitatory neurons with local inhibitory interneuron feedback that forms a set of nonlinear oscillators coupled only by long-range excitatory connections. Using a local Hebb-like learning rule for primary and higher-order synapses at the ends of the long-range connections, the system learns to store the kinds of oscillation amplitude patterns observed in olfactory and visual cortex. In olfaction, these patterns “emerge” during respiration by a pattern forming phase transition which we characterize in the model as a multiple Hopf bifurcation. We argue that these bifurcations play an important role in the operation of real digital computers and neural networks, and we use bifurcation theory to derive learning rules which analytically guarantee CAM storage of continuous periodic sequences-capacity: N/2 Fourier components for an N-node network-no “spurious” attractors.
Stability and bifurcation for Marchuk's model of an immune system
Marzuki, Ira Syazwani Mohamad; Roslan, Ummu'Atiqah Mohd
2017-08-01
The investigation of an immune system has long been and will continue to be one of dominant themes in both ecology and biology due to its importance. In this paper, we consider Marchuk's model of an immune system where this model is governed by a system of three differential equations with time. This model has two equilibrium states which are healthy state and chronic state. It is healthy state when the antigen reproduction is small while chronic state is when antigen reproduction rate is large. The objectives of this paper are to analyse the stability of this model, to summarize this stability using bifurcation diagram and to discuss interaction between the healthy and chronic states at stationary solution. The methods involved are stability theory and bifurcation theory. Our results show that healthy states are saddle and only one chronic state is asymptotically stable for a region of parameter considered. For the bifurcation's case, as we increase the value of a parameter in this model, the chronic state shows that there are increment in the number of antigen, plasma cell and the antibody production.
The Quantum Mechanics Solver: How to Apply Quantum Theory to Modern Physics, 2nd edition
Energy Technology Data Exchange (ETDEWEB)
Robbin, J M [School of Mathematics, University Walk, Bristol, BS8 1TW (United Kingdom)
2007-07-20
into three sections: Elementary Particles, Nuclei and Atoms; Quantum Entanglement and Measurement; and Complex Systems. The coverage is not comprehensive; there is little on scattering theory, for example, and some areas of recent interest, such as topological aspects of quantum mechanics and semiclassics, are not included. The problems are based on examination questions given at the Ecole Polytechnique in the last 15 years. The book is accessible to undergraduates, but working physicists should find it a delight. (Book review of 'The Quantum Mechanics Solver: How to Apply Quantum Theory to Modern Physics, 2nd edition', Jean-Loius Basdevant and Jean Dalibard , 2006 Springer, ISBN 978-3-540-27721-7)
Yang, Chao-Ming; Hsu, Tzu-Fan
2017-01-01
Visual communication design (VCD) is a form of nonverbal communication. The application of relevant linguistic or semiotic theories to VCD education renders graphic design an innovative and scientific discipline. In this study, actual teaching activities were examined to verify the feasibility of applying narrative theory to graphic design…
Lincoln, Yvonna S.; Lynham, Susan A.
2007-01-01
Utilizing Patterson's (1983) eight criteria for assessing theory in applied fields from a conventional (empirical-analytical) perspective, these criteria are evaluated and where applicable reconstructed from an interpretive (social constructivist) perspective of theory building research and assessment. Four additional criteria are proposed and…
Fully developed turbulence via Feigenbaum's period-doubling bifurcations
International Nuclear Information System (INIS)
Duong-van, M.
1987-08-01
Since its publication in 1978, Feigenbaum's predictions of the onset of turbulence via period-doubling bifurcations have been thoroughly borne out experimentally. In this paper, Feigenbaum's theory is extended into the regime in which we expect to see fully developed turbulence. We develop a method of averaging that imposes correlations in the fluctuating system generated by this map. With this averaging method, the field variable is obtained by coarse-graining, while microscopic fluctuations are preserved in all averaging scales. Fully developed turbulence will be shown to be a result of microscopic fluctuations with proper averaging. Furthermore, this model preserves Feigenbaum's results on the physics of bifurcations at the onset of turbulence while yielding additional physics both at the onset of turbulence and in the fully developed turbulence regime
Limit cycles bifurcating from a perturbed quartic center
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Coll, Bartomeu, E-mail: dmitcv0@ps.uib.ca [Dept. de Matematiques i Informatica, Universitat de les Illes Balears, Facultat de ciencies, 07071 Palma de Mallorca (Spain); Llibre, Jaume, E-mail: jllibre@mat.uab.ca [Dept. de Matematiques, Universitat Autonoma de Barcelona, Edifici Cc 08193 Bellaterra, Barcelona, Catalonia (Spain); Prohens, Rafel, E-mail: dmirps3@ps.uib.ca [Dept. de Matematiques i Informatica, Universitat de les Illes Balears, Facultat de ciencies, 07071 Palma de Mallorca (Spain)
2011-04-15
Highlights: We study polynomial perturbations of a quartic center. We get simultaneous upper and lower bounds for the bifurcating limit cycles. A higher lower bound for the maximum number of limit cycles is obtained. We obtain more limit cycles than the number obtained in the cubic case. - Abstract: We consider the quartic center x{sup .}=-yf(x,y),y{sup .}=xf(x,y), with f(x, y) = (x + a) (y + b) (x + c) and abc {ne} 0. Here we study the maximum number {sigma} of limit cycles which can bifurcate from the periodic orbits of this quartic center when we perturb it inside the class of polynomial vector fields of degree n, using the averaging theory of first order. We prove that 4[(n - 1)/2] + 4 {<=} {sigma} {<=} 5[(n - 1)/2] + 14, where [{eta}] denotes the integer part function of {eta}.
Liu, Ping; Shi, Junping
2018-01-01
The bifurcation of non-trivial steady state solutions of a scalar reaction-diffusion equation with nonlinear boundary conditions is considered using several new abstract bifurcation theorems. The existence and stability of positive steady state solutions are proved using a unified approach. The general results are applied to a Laplace equation with nonlinear boundary condition and bistable nonlinearity, and an elliptic equation with superlinear nonlinearity and sublinear boundary conditions.
Bifurcation analysis in delayed feedback Jerk systems and application of chaotic control
International Nuclear Information System (INIS)
Zheng Baodong; Zheng Huifeng
2009-01-01
Jerk systems with delayed feedback are considered. Firstly, by employing the polynomial theorem to analyze the distribution of the roots to the associated characteristic equation, the conditions of ensuring the existence of Hopf bifurcation are given. Secondly, the stability and direction of the Hopf bifurcation are determined by applying the normal form method and center manifold theorem. Finally, the application to chaotic control is investigated, and some numerical simulations are carried out to illustrate the obtained results.
Suramlishvili, Nugzar; Eggers, Jens; Fontelos, Marco
2014-11-01
We are concerned with singularities of the shock fronts of converging perturbed shock waves. Our considerations are based on Whitham's theory of geometrical shock dynamics. The recently developed method of local analysis is applied in order to determine generic singularities. In this case the solutions of partial differential equations describing the geometry of the shock fronts are presented as families of smooth maps with state variables and the set of control parameters dependent on Mach number, time and initial conditions. The space of control parameters of the singularities is analysed, the unfoldings describing the deformations of the canonical germs of shock front singularities are found and corresponding bifurcation diagrams are constructed. Research is supported by the Leverhulme Trust, Grant Number RPG-2012-568.
On bifurcations of temperature profiles
International Nuclear Information System (INIS)
Bachmann, P.; Suender, D.; Wobig, H.
1998-01-01
Multiple stationary solutions of the one-dimensional heat conduction equation and bifurcation phenomena are known to be caused by the non-monotonic dependence of the impurity radiation function on the temperature, and the non-linearity of the heat flux in the high-recycling regime in front of the divertor target plates. In this paper we report on bifurcation and time evolution of temperature profiles along the magnetic field lines between two target plates owing to localized heat sources and energy loss due to the radiation of different impurities which are described by simple model functions. The main result is that depending on the number of different impurity species and their densities there may exist multiple stationary profiles. A linear stability analysis of stationary temperature profiles leads to a Schroedinger-type equation for the temperature perturbation. Then the fully time-dependent problem is solved. For the case of two different impurity species there is a maximum of seven steady temperature profiles with four of them proved to be stable. (orig.)
Applying Bayesian decision theory to assess reprocessing economic and social cost-benefits
International Nuclear Information System (INIS)
Heising, C.D.
1978-01-01
Bayesian decision theory, combined with conventional systems analysis techniques into the discipline called decision analysis, has been applied in this work to assess economic and social cost-benefits associated with reprocessing nuclear fuel. Particular attention in this paper is given to the models which have been developed to place numerical estimates in dollar terms on the three categories of social risks that have been identified with reprocessing. These categories include: (1) health, environment, and safety, (2) diversion of fissile material, including sabotage, terrorist acts, and subnational diversion, and (3) nuclear proliferation, defined to be a diversion at the national level to obtain weapons capability. The emphasis is placed on the third category, as proliferation risk has not been treated elsewhere in a quantitative fashion; most arguments have in the main been qualitative conjectures put forth by political scientists
Jalilian, Farzad; Allahverdipour, Hamid; Moeini, Babak; Moghimbeigi, Abbas
2011-01-01
Use of anabolic androgenic steroids (AAS) has been associated with adverse physical and psychiatric effects and it is known as rising problem among youth people. This study was conducted to evaluate anabolic steroids preventative intervention efficiency among gym users in Iran and theory of planned behaviour was applied as theoretical framework. Overall, 120 male gym users participated in this study as intervention and control group. This was a longitudinal randomized pretest - posttest series control group design panel study to implement a behaviour modification based intervention to prevent AAS use. Cross -tabulation and t-test by using SPSS statistical package, version 13 was used for the statistical analysis. It was found significant improvements in average response for knowledge about side effects of AAS (Pgym users and ado-lescences would be effective to improve adolescents' healthy behaviors and intend them not to use AAS.
Hannan, Thomas E; Moffitt, Robyn L; Neumann, David L; Thomas, Patrick R
2015-10-01
This study explored whether mental toughness, the capacity to maintain performance under pressure, moderated the relation between physical activity intentions and subsequent behavior. Participants (N = 117) completed the Mental Toughness Index and a theory of planned behavior questionnaire. Seven days later, physical activity was assessed using the International Physical Activity Questionnaire. Attitudes, subjective norms, and perceived behavioral control explained substantial variance (63.1%) in physical activity intentions. Intentions also significantly predicted physical activity behavior. The simple slopes analyses for the moderation effect revealed a nonsignificant intention-behavior relation at low levels of mental toughness. However, intentions were significantly and positively related to physical activity when mental toughness was moderate or high, suggesting that the development of a mentally tough mindset may reduce the gap between behavior and physical activity intention. Future research is needed to confirm these findings and apply them in the design of mental toughness interventions to facilitate physical activity engagement.
Gatlin, L. L.
1974-01-01
Concepts of information theory are applied to examine various proteins in terms of their redundancy in natural originators such as animals and plants. The Monte Carlo method is used to derive information parameters for random protein sequences. Real protein sequence parameters are compared with the standard parameters of protein sequences having a specific length. The tendency of a chain to contain some amino acids more frequently than others and the tendency of a chain to contain certain amino acid pairs more frequently than other pairs are used as randomness measures of individual protein sequences. Non-periodic proteins are generally found to have random Shannon redundancies except in cases of constraints due to short chain length and genetic codes. Redundant characteristics of highly periodic proteins are discussed. A degree of periodicity parameter is derived.
A generalized number theory problem applied to ideal liquids and to terminological lexis
Maslov, V. P.; Maslova, T. V.
2017-01-01
We consider the notion of number of degrees of freedom in number theory and thermodynamics. This notion is applied to notions of terminology such as terms, slogans, themes, rules, and regulations. Prohibitions are interpreted as restrictions on the number of degrees of freedom. We present a theorem on the small number of degrees of freedom as a consequence of the generalized partitio numerorum problem. We analyze the relationship between thermodynamically ideal liquids with the lexical background that a term acquires in the process of communication. Examples showing how this background may be enhanced are considered. We discuss the question of the coagulation of drops in connection with the forecast of analogs of the gas-ideal liquid phase transition in social-political processes.
Blanchard, Yvette; Øberg, Gunn Kristin
2015-01-01
Physical therapy involving newborns and young infants is a specialized area of practice reserved for therapists who have advanced training and the competence to help newborns, young infants and their families meet their goals. Beginning at birth, infants apply a significant amount of effort to actively participate in and shape their world. Infants make their intentions and requests for support known through their behaviors during social and physical therapy encounters. The therapeutic encounter viewed from the infant's perspective has received limited attention in the physical therapy literature. The purpose of this article is to discuss concepts related to phenomenology and synactive theory that are relevant to physical therapy with newborns and young infants during the first few months of life after birth.
Polo, Victor; Andres, Juan; Berski, Slawomir; Domingo, Luis R; Silvi, Bernard
2008-08-07
Thom's catastrophe theory applied to the evolution of the topology of the electron localization function (ELF) gradient field constitutes a way to rationalize the reorganization of electron pairing and a powerful tool for the unambiguous determination of the molecular mechanisms of a given chemical reaction. The identification of the turning points connecting the ELF structural stability domains along the reaction pathway allows a rigorous characterization of the sequence of electron pair rearrangements taking place during a chemical transformation, such as multiple bond forming/breaking processes, ring closure processes, creation/annihilation of lone pairs, transformations of C-C multiple bonds into single ones. The reaction mechanism of some relevant organic reactions: Diels-Alder, 1,3-dipolar cycloaddition and Cope rearrangement are reviewed to illustrate the potential of the present approach.
Z-1 perturbation theory applied to the correlation energy problem of atoms
International Nuclear Information System (INIS)
Robinson, B.H.
1975-01-01
Rayleigh--Schroedinger Perturbation Theory is applied to obtain directly exact and explicit analytic formulas for the electron correlation energies of N electron systems in terms of their pairwise interactions through second order in Z -1 , where Z is the nucleus of the atom. It is demonstrated that the second order correlation energy may be expressed as exactly the sum of pairwise correlation energies. In the case of no zeroth order degeneracy, the zeroth and first order terms vanish. The expression for the pairwise energies is an infinite sum, all terms of which are of the same sign. There is no numerical differencing. In the case of zeroth order degeneracy it is shown that the above statement concerning the second order energy still holds, but the expressions are a bit more complicated. It is shown that they ''almost'' reduce to a much simpler form. Also, the computation of the first order correlation energy is considered
Sender-receiver systems and applying information theory for quantitative synthetic biology.
Barcena Menendez, Diego; Senthivel, Vivek Raj; Isalan, Mark
2015-02-01
Sender-receiver (S-R) systems abound in biology, with communication systems sending information in various forms. Information theory provides a quantitative basis for analysing these processes and is being applied to study natural genetic, enzymatic and neural networks. Recent advances in synthetic biology are providing us with a wealth of artificial S-R systems, giving us quantitative control over networks with a finite number of well-characterised components. Combining the two approaches can help to predict how to maximise signalling robustness, and will allow us to make increasingly complex biological computers. Ultimately, pushing the boundaries of synthetic biology will require moving beyond engineering the flow of information and towards building more sophisticated circuits that interpret biological meaning. Copyright © 2014. Published by Elsevier Ltd.
Bifurcating optical pattern recognition in photorefractive crystals
Liu, Hua-Kuang
1993-01-01
A new concept and experimental demonstration of a bifurcating optical pattern recognizer that uses a nonlinear gain saturation memory medium such as a high-gain photorefractive crystal are presented. A barium titanate crystal is used as a typical example of the nonlinear medium for the demonstration of the bifurcating optical pattern recognizer.
Bifurcations in stochastic equations with delayed feedback
Gaudreault, Mathieu
The bifurcation diagram of a model stochastic differential equation with delayed feedback is presented. We are motivated by recent research on stochastic effects in models of transcriptional gene regulation. We start from the normal form for a pitchfork bifurcation, and add multiplicative or parametric noise and linear delayed feedback. The latter is sufficient to originate a Hopf bifurcation in that region of parameters in which there is a sufficiently strong negative feedback. We find a sharp bifurcation in parameter space, and define the threshold as the point in which the stationary distribution function p(x) changes from a delta function at the trivial state x = 0 to p( x) ˜ xalpha at small x (with alpha = 1 exactly at threshold). We find that the bifurcation threshold is shifted by fluctuations relative to the deterministic limit by an amount that scales linearly with the noise intensity. Analytical expressions for pitchfork and Hopf bifurcation thresholds are given for the model considered. Our results assume that the delay time tau is small compared to other characteristic time scales, not a significant limitation close to the bifurcation line. A pitchfork bifurcation line is found, the location of which depends on the conditional average , where x(t) is the dynamical variable. This conditional probability incorporates the combined effect of fluctuation correlations and delayed feedback. We also find a Hopf bifurcation line which is obtained by a multiple scale expansion around the oscillatory solution near threshold. We solve the Fokker-Planck equation associated with the slowly varying amplitudes and use it to determine the threshold location. In both cases, the predicted bifurcation lines are in excellent agreement with a direct numerical integration of the governing equations. Contrary to the known case involving no delayed feedback, we show that the stochastic bifurcation lines are shifted relative to the deterministic limit and hence that the
Voltage stability, bifurcation parameters and continuation methods
Energy Technology Data Exchange (ETDEWEB)
Alvarado, F.L. [Wisconsin Univ., Madison, WI (United States)
1994-12-31
This paper considers the importance of the choice of bifurcation parameter in the determination of the voltage stability limit and the maximum power load ability of a system. When the bifurcation parameter is power demand, the two limits are equivalent. However, when other types of load models and bifurcation parameters are considered, the two concepts differ. The continuation method is considered as a method for determination of voltage stability margins. Three variants of the continuation method are described: the continuation parameter is the bifurcation parameter the continuation parameter is initially the bifurcation parameter, but is free to change, and the continuation parameter is a new `arc length` parameter. Implementations of voltage stability software using continuation methods are described. (author) 23 refs., 9 figs.
Bifurcation of the spin-wave equations
International Nuclear Information System (INIS)
Cascon, A.; Koiller, J.; Rezende, S.M.
1990-01-01
We study the bifurcations of the spin-wave equations that describe the parametric pumping of collective modes in magnetic media. Mechanisms describing the following dynamical phenomena are proposed: (i) sequential excitation of modes via zero eigenvalue bifurcations; (ii) Hopf bifurcations followed (or not) by Feingenbaum cascades of period doubling; (iii) local and global homoclinic phenomena. Two new organizing center for routes to chaos are identified; in the classification given by Guckenheimer and Holmes [GH], one is a codimension-two local bifurcation, with one pair of imaginary eigenvalues and a zero eigenvalue, to which many dynamical consequences are known; secondly, global homoclinic bifurcations associated to splitting of separatrices, in the limit where the system can be considered a Hamiltonian subjected to weak dissipation and forcing. We outline what further numerical and algebraic work is necessary for the detailed study following this program. (author)
Quantum correlated cluster mean-field theory applied to the transverse Ising model.
Zimmer, F M; Schmidt, M; Maziero, Jonas
2016-06-01
Mean-field theory (MFT) is one of the main available tools for analytical calculations entailed in investigations regarding many-body systems. Recently, there has been a surge of interest in ameliorating this kind of method, mainly with the aim of incorporating geometric and correlation properties of these systems. The correlated cluster MFT (CCMFT) is an improvement that succeeded quite well in doing that for classical spin systems. Nevertheless, even the CCMFT presents some deficiencies when applied to quantum systems. In this article, we address this issue by proposing the quantum CCMFT (QCCMFT), which, in contrast to its former approach, uses general quantum states in its self-consistent mean-field equations. We apply the introduced QCCMFT to the transverse Ising model in honeycomb, square, and simple cubic lattices and obtain fairly good results both for the Curie temperature of thermal phase transition and for the critical field of quantum phase transition. Actually, our results match those obtained via exact solutions, series expansions or Monte Carlo simulations.
Dimensional analysis and extended hydrodynamic theory applied to long-rod penetration of ceramics
Directory of Open Access Journals (Sweden)
J.D. Clayton
2016-08-01
Full Text Available Principles of dimensional analysis are applied in a new interpretation of penetration of ceramic targets subjected to hypervelocity impact. The analysis results in a power series representation – in terms of inverse velocity – of normalized depth of penetration that reduces to the hydrodynamic solution at high impact velocities. Specifically considered are test data from four literature sources involving penetration of confined thick ceramic targets by tungsten long rod projectiles. The ceramics are AD-995 alumina, aluminum nitride, silicon carbide, and boron carbide. Test data can be accurately represented by the linear form of the power series, whereby the same value of a single fitting parameter applies remarkably well for all four ceramics. Comparison of the present model with others in the literature (e.g., Tate's theory demonstrates a target resistance stress that depends on impact velocity, linearly in the limiting case. Comparison of the present analysis with recent research involving penetration of thin ceramic tiles at lower typical impact velocities confirms the importance of target properties related to fracture and shear strength at the Hugoniot Elastic Limit (HEL only in the latter. In contrast, in the former (i.e., hypervelocity and thick target experiments, the current analysis demonstrates dominant dependence of penetration depth only by target mass density. Such comparisons suggest transitions from microstructure-controlled to density-controlled penetration resistance with increasing impact velocity and ceramic target thickness.
Brown, Jonathan M.; Petersen, Jeremy D.
2014-01-01
NASA's WIND mission has been operating in a large amplitude Lissajous orbit in the vicinity of the interior libration point of the Sun-Earth/Moon system since 2004. Regular stationkeeping maneuvers are required to maintain the orbit due to the instability around the collinear libration points. Historically these stationkeeping maneuvers have been performed by applying an incremental change in velocity, or (delta)v along the spacecraft-Sun vector as projected into the ecliptic plane. Previous studies have shown that the magnitude of libration point stationkeeping maneuvers can be minimized by applying the (delta)v in the direction of the local stable manifold found using dynamical systems theory. This paper presents the analysis of this new maneuver strategy which shows that the magnitude of stationkeeping maneuvers can be decreased by 5 to 25 percent, depending on the location in the orbit where the maneuver is performed. The implementation of the optimized maneuver method into operations is discussed and results are presented for the first two optimized stationkeeping maneuvers executed by WIND.
[Applying the Theory of Planned Behavior: Which factors influence on doing physical exercise?].
Neipp, Mari Carmen; Quiles, María José; León, Eva; Tirado, Sonia; Rodríguez-Marín, Jesús
2015-05-01
The purpose of this study was analyzed the influence of attitude, subjective norm, and Perceived behavioral control (PBC) on intention of doing physical exercise in a group of people. Cross-sectional and observational study. Questionnaire was applied to general population in the province of Alicante 679 people who practiced physical exercise in the province of Alicante. It was applied a questionnaire measuring the components of the Theory of Plan Behavior model (TPB). Results showed that variables of the model (TPB) had good fit to the data. Moreover, subjective norm and perceived behavioural control had a significant impact on intention and the three variables explained 61% of its variance. Findings supported the important role of TPB in the context of physical exercise. Perceived behavioral control was the strongest predictor of intention to practice physical exercise. A possible intervention might lead to implement programs focused in increasing control perception of people to engage in physical exercise. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Duarte-Galvan, C.; Torres-Pacheco, I.; Guevara-Gonzalez, R. G.; Romero-Troncoso, R. J.; Contreras-Medina, L. M.; Rios-Alcaraz, M. A.; Millan-Almaraz, J. R.
2012-07-01
Today agriculture is changing in response to the requirements of modern society, where ensuring food supply through practices such as water conservation, reduction of agrochemicals and the required planted surface, which guarantees high quality crops are in demand. Greenhouses have proven to be a reliable solution to achieve these goals; however, a greenhouse as a means for protected agriculture has the potential to lead to serious problems. The most of these are related to the inside greenhouse climate conditions where controlling the temperature and relative humidity (RH) are the main objectives of engineering. Achieving appropriate climate conditions to ensure high yield and quality crops reducing energy consumption have been the objective of investigations for some time. Different schemes in control theories have been applied in this field to solve the aforementioned problems. Therefore, the objective of this paper is to present a review of different control techniques applied in protected agriculture to manage greenhouse climate conditions, presenting advantages and disadvantages of developed control platforms in order to suggest a design methodology according to results obtained from different investigations. (Author) 64 refs.
Improving Patient Safety in Clinical Oncology: Applying Lessons From Normal Accident Theory.
Chera, Bhishamjit S; Mazur, Lukasz; Buchanan, Ian; Kim, Hong Jin; Rockwell, John; Milowsky, Matthew I; Marks, Lawrence B
2015-10-01
Concerns for patient safety persist in clinical oncology. Within several nonmedical areas (eg, aviation, nuclear power), concepts from Normal Accident Theory (NAT), a framework for analyzing failure potential within and between systems, have been successfully applied to better understand system performance and improve system safety. Clinical oncology practice is interprofessional and interdisciplinary, and our therapies often have narrow therapeutic windows. Thus, many of our processes are, in NAT terms, interactively complex and tightly coupled within and across systems and are therefore prone to unexpected behaviors that can result in substantial patient harm. To improve safety at the University of North Carolina, we have applied the concepts of NAT to our practice to better understand our systems' behavior and adopted strategies to reduce complexity and coupling. Furthermore, recognizing that we cannot eliminate all risks, we have stressed safety mindfulness among our staff to further promote safety. Many specific examples are provided herein. The lessons from NAT are translatable to clinical oncology and may help to promote safety.
Applying Fear Appeals Theory for Preventing Drug Abuse among Male High School Students in Tehran
Directory of Open Access Journals (Sweden)
K. Witte
2006-10-01
Full Text Available Introduction & Objective: Drug abuse is one of the complicated phenomenons in the human communities that it produces health problems. The effect of applying fear appeal message on attitudes and intention against drug abuse, drug resistance skills, knowledge about side effect of drugs and drug abuse related behaviors among male high school students was studied based on applying extended parallel process model as a theoretical framework. Materials & Methods: Two high schools were chosen from six state high schools as an intervention (n=86 and control (n=97 groups. Educational curriculum, that was designed, based on students’ educational needs, appealed students’ fear and recommended messages developed students' ability for resisting against drugs. Before intervention 5-6 students who were known as a favourite and leader of students, were selected by student’s opinion in each class as students' leaders. The each leader of the group had a coordinator and mediate role between his group and health educators. Henceforth a favourite teacher was chosen by students’ vote for helping health educators and participated in the educational intervention program.Results: The result showed that educational manipulation had significant effect on intervention group’s average response for intention (t= -4.03, p<0.000 and attitude against drug abuse (t= -6.19, p<0.000, peer resistance skills (t=-0.82, p<0.000, and knowledge (t= -10.88, p<0.000. In addition, it was not found positive urinary rapid immune-chromatography test for opium and marijuana in the intervention group whereas 6.3% in the control groups.Conclusion: This findings suggest that applying fear appeals theories and effective health risk message would be an efficient tool for preventing drug abuse education programs but further studies are needed to define function of EPPM as a effective model for creating social inoculation against drug abuse among non- drug expose adolescents.
Priest, Susanna Hornig; Greenhalgh, Ted; Neill, Helen R.; Young, Gabriel Reuben
2015-01-01
Diffusion theory, developed and popularized within communication research by Everett Rogers, is a venerable approach with much to recommend it as a theoretical foundation for applied communication research. In developing an applied project for a home energy conservation (energy efficiency retrofit) program in the state of Nevada, we utilized key…
Growth and Magnetic Properties of Polycrystalline Self-Assembled Bifurcated Co Nanowires
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Jesse Silverberg
2008-01-01
Full Text Available We use anodization of aluminum foil with variable applied anodization voltage to create an alumina template with bifurcated porous structures. The template is then used to electrodeposit Co, fabricating unique bifurcated Co nanowires. In order to better understand the crystal structure of our new material, we then report magnetic properties of these self-assembled bifurcated Co nanowires. Magnetic measurements of the bifurcated wires are studied as functions of branch/stem ratios, wire length, and temperature. The results are compared with those of straight Co nanowires of similar dimensions and thin film Co samples to find that a different crystal lattice structure prevails in the stems than in the branches of the wires.
Applying Psychological Theories to Promote Long-Term Maintenance of Health Behaviors
Joseph, Rodney P.; Daniel, Casey L.; Thind, Herpreet; Benitez, Tanya J.; Pekmezi, Dori
2014-01-01
Behavioral health theory provides a framework for researchers to design, implement, and evaluate the effects of health promotion programs. However, limited research has examined theories used in interventions to promote long-term maintenance of health behaviors. The purpose of this review was to evaluate the available literature and identify prominent behavioral health theories used in intervention research to promote maintenance of health behaviors. We reviewed theories used in intervention research assessing long-term maintenance (≥ 6 months post-intervention) of physical activity, weight loss, and smoking cessation. Five prominent behavioral theories were referenced by the 34 studies included in the review: Self-Determination Theory, Theory of Planned Behavior, Social Cognitive Theory, Transtheoretical Model, and Social Ecological Model. Descriptions and examples of applications of these theories are provided. Implications for future research are discussed. PMID:28217036
Resampling method for applying density-dependent habitat selection theory to wildlife surveys.
Tardy, Olivia; Massé, Ariane; Pelletier, Fanie; Fortin, Daniel
2015-01-01
Isodar theory can be used to evaluate fitness consequences of density-dependent habitat selection by animals. A typical habitat isodar is a regression curve plotting competitor densities in two adjacent habitats when individual fitness is equal. Despite the increasing use of habitat isodars, their application remains largely limited to areas composed of pairs of adjacent habitats that are defined a priori. We developed a resampling method that uses data from wildlife surveys to build isodars in heterogeneous landscapes without having to predefine habitat types. The method consists in randomly placing blocks over the survey area and dividing those blocks in two adjacent sub-blocks of the same size. Animal abundance is then estimated within the two sub-blocks. This process is done 100 times. Different functional forms of isodars can be investigated by relating animal abundance and differences in habitat features between sub-blocks. We applied this method to abundance data of raccoons and striped skunks, two of the main hosts of rabies virus in North America. Habitat selection by raccoons and striped skunks depended on both conspecific abundance and the difference in landscape composition and structure between sub-blocks. When conspecific abundance was low, raccoons and striped skunks favored areas with relatively high proportions of forests and anthropogenic features, respectively. Under high conspecific abundance, however, both species preferred areas with rather large corn-forest edge densities and corn field proportions. Based on random sampling techniques, we provide a robust method that is applicable to a broad range of species, including medium- to large-sized mammals with high mobility. The method is sufficiently flexible to incorporate multiple environmental covariates that can reflect key requirements of the focal species. We thus illustrate how isodar theory can be used with wildlife surveys to assess density-dependent habitat selection over large
Lee, Jounghee; Jeong, Soyeon; Ko, Gyeongah; Park, Hyunshin; Ko, Youngsook
2016-08-01
The purpose of this study was to develop an educational model regarding food safety and nutrition. In particular, we aimed to develop educational materials, such as middle- and high-school textbooks, a teacher's guidebook, and school posters, by applying social cognitive theory. To develop a food safety and nutrition education program, we took into account diverse factors influencing an individual's behavior, such as personal, behavioral, and environmental factors, based on social cognitive theory. We also conducted a pilot study of the educational materials targeting middle-school students (n = 26), high-school students (n = 24), and dietitians (n = 13) regarding comprehension level, content, design, and quality by employing the 5-point Likert scale in May 2016. The food safety and nutrition education program covered six themes: (1) caffeine; (2) food additives; (3) foodborne illness; (4) nutrition and meal planning; (5) obesity and eating disorders; and (6) nutrition labeling. Each class activity was created to improve self-efficacy by setting one's own goal and to increase self-control by monitoring one's dietary intake. We also considered environmental factors by creating school posters and leaflets to educate teachers and parents. The overall evaluation score for the textbook was 4.0 points among middle- and high-school students, and 4.5 points among dietitians. This study provides a useful program model that could serve as a guide to develop educational materials for nutrition-related subjects in the curriculum. This program model was created to increase awareness of nutrition problems and self-efficacy. This program also helped to improve nutrition management skills and to promote a healthy eating environment in middle- and high-school students.
Model Reduction of Nonlinear Aeroelastic Systems Experiencing Hopf Bifurcation
Abdelkefi, Abdessattar
2013-06-18
In this paper, we employ the normal form to derive a reduced - order model that reproduces nonlinear dynamical behavior of aeroelastic systems that undergo Hopf bifurcation. As an example, we consider a rigid two - dimensional airfoil that is supported by nonlinear springs in the pitch and plunge directions and subjected to nonlinear aerodynamic loads. We apply the center manifold theorem on the governing equations to derive its normal form that constitutes a simplified representation of the aeroelastic sys tem near flutter onset (manifestation of Hopf bifurcation). Then, we use the normal form to identify a self - excited oscillator governed by a time - delay ordinary differential equation that approximates the dynamical behavior while reducing the dimension of the original system. Results obtained from this oscillator show a great capability to predict properly limit cycle oscillations that take place beyond and above flutter as compared with the original aeroelastic system.
Bifurcation and chaos of an axially accelerating viscoelastic beam
International Nuclear Information System (INIS)
Yang Xiaodong; Chen Liqun
2005-01-01
This paper investigates bifurcation and chaos of an axially accelerating viscoelastic beam. The Kelvin-Voigt model is adopted to constitute the material of the beam. Lagrangian strain is used to account for the beam's geometric nonlinearity. The nonlinear partial-differential equation governing transverse motion of the beam is derived from the Newton second law. The Galerkin method is applied to truncate the governing equation into a set of ordinary differential equations. By use of the Poincare map, the dynamical behavior is identified based on the numerical solutions of the ordinary differential equations. The bifurcation diagrams are presented in the case that the mean axial speed, the amplitude of speed fluctuation and the dynamic viscoelasticity is respectively varied while other parameters are fixed. The Lyapunov exponent is calculated to identify chaos. From numerical simulations, it is indicated that the periodic, quasi-periodic and chaotic motions occur in the transverse vibrations of the axially accelerating viscoelastic beam
Directory of Open Access Journals (Sweden)
Peter G. Schrader
2016-01-01
Full Text Available User You are logged in as... mocak My Profile Log Out Log Out as User Journal Content Search Search Scope Browse By Issue By Author By Title Indexing/Abstracting -Doaj -Google Scholar -J Gate/Informatics -Ulrich's Under review by: -Ebsco -Journal Seek -info BASE INDEX -ERIC -Ulakbim/tr index Article Tools Abstract Print this article Indexing metadata How to cite item Finding References Review policy Email this article Email the author Related Items Show all The fourth issue of Journal of Learning and Teaching in Digital Age(JOLTIDA has been published. Editorial Board Open Journal Systems Journal Help Notifications View (564 new Manage Information For Readers For Authors For Librarians Creative Commons License Font Size Make font size smaller Make font size default Make font size larger Home About User Home Search Current Archives Announcements Home > Vol 1, No 1 (2016 > Schrader DOES MULTIMEDIA THEORY APPLY TO ALL STUDENTS? THE IMPACT OF MULTIMEDIA PRESENTATIONS ON SCIENCE LEARNING Peter G. Schrader University of Nevada Las Vegas, USA pg.schrader@unlv.edu Eric E. Rapp ericrapp@icloud.com ABSTRACT In K-12 school settings in the United States, there is a preponderance of information delivered via multimedia to students everyday (e.g., visual aids found in science textbooks, electronic tablets, streamed video content, web pages, animations, and PowerPoint presentations. The cognitive theory of multimedia learning (CTML outlines numerous principles associated with learning from and with multimedia (Mayer, Hegarty, Mayer, & Cambell, 2005. However, the bulk of the research like the CTML has been conducted using college age students (Jones, 2010; McTigue, 2009. There is ample evidence that college age students and younger students exhibit numerous and important differences when learning from multimedia content (Hannus & Hyona, 1999; McTique, 2009; Moreno, 2007; Van Parreren, 1983. As a result, the objective of the current study is to examine the
Nonlinear stability control and λ-bifurcation
International Nuclear Information System (INIS)
Erneux, T.; Reiss, E.L.; Magnan, J.F.; Jayakumar, P.K.
1987-01-01
Passive techniques for nonlinear stability control are presented for a model of fluidelastic instability. They employ the phenomena of λ-bifurcation and a generalization of it. λ-bifurcation occurs when a branch of flutter solutions bifurcates supercritically from a basic solution and terminates with an infinite period orbit at a branch of divergence solutions which bifurcates subcritically from the basic solution. The shape of the bifurcation diagram then resembles the greek letter λ. When the system parameters are in the range where flutter occurs by λ-bifurcation, then as the flow velocity increase the flutter amplitude also increases, but the frequencies of the oscillations decrease to zero. This diminishes the damaging effects of structural fatigue by flutter, and permits the flow speed to exceed the critical flutter speed. If generalized λ-bifurcation occurs, then there is a jump transition from the flutter states to a divergence state with a substantially smaller amplitude, when the flow speed is sufficiently larger than the critical flutter speed
Bifurcations of mixed-mode oscillations in a stellate cell model
Wechselberger, Martin; Weckesser, Warren
2009-08-01
Experimental recordings of the membrane potential of stellate cells within the entorhinal cortex show a transition from subthreshold oscillations (STOs) via mixed-mode oscillations (MMOs) to relaxation oscillations under increased injection of depolarizing current. Acker et al. introduced a 7D conductance based model which reproduces many features of the oscillatory patterns observed in these experiments. For the first time, we present a comprehensive bifurcation analysis of this model by using the software package AUTO. In particular, we calculate the stable MMO branches within the bifurcation diagram of this model, as well as other MMO patterns which are unstable. We then use geometric singular perturbation theory to demonstrate how the bifurcations are governed by a 3D reduced model introduced by Rotstein et al. We extend their analysis to explain all observed MMO patterns within the bifurcation diagram. A key role in this bifurcation analysis is played by a novel homoclinic bifurcation structure connecting to a saddle equilibrium on the unstable branch of the corresponding critical manifold. This type of homoclinic connection is possible due to canards of folded node (folded saddle-node) type.
Nonresonant Double Hopf Bifurcation in Toxic Phytoplankton-Zooplankton Model with Delay
Yuan, Rui; Jiang, Weihua; Wang, Yong
This paper investigates a toxic phytoplankton-zooplankton model with Michaelis-Menten type phytoplankton harvesting. The model has rich dynamical behaviors. It undergoes transcritical, saddle-node, fold, Hopf, fold-Hopf and double Hopf bifurcation, when the parameters change and go through some of the critical values, the dynamical properties of the system will change also, such as the stability, equilibrium points and the periodic orbit. We first study the stability of the equilibria, and analyze the critical conditions for the above bifurcations at each equilibrium. In addition, the stability and direction of local Hopf bifurcations, and the completion bifurcation set by calculating the universal unfoldings near the double Hopf bifurcation point are given by the normal form theory and center manifold theorem. We obtained that the stable coexistent equilibrium point and stable periodic orbit alternate regularly when the digestion time delay is within some finite value. That is, we derived the pattern for the occurrence, and disappearance of a stable periodic orbit. Furthermore, we calculated the approximation expression of the critical bifurcation curve using the digestion time delay and the harvesting rate as parameters, and determined a large range in terms of the harvesting rate for the phytoplankton and zooplankton to coexist in a long term.
Ternary choices in repeated games and border collision bifurcations
International Nuclear Information System (INIS)
Dal Forno, Arianna; Gardini, Laura; Merlone, Ugo
2012-01-01
Highlights: ► We extend a model of binary choices with externalities to include more alternatives. ► Introducing one more option affects the complexity of the dynamics. ► We find bifurcation structures which where impossible to observe in binary choices. ► A ternary choice cannot simply be considered as a binary choice plus one. - Abstract: Several recent contributions formalize and analyze binary choices games with externalities as those described by Schelling. Nevertheless, in the real world choices are not always binary, and players have often to decide among more than two alternatives. These kinds of interactions are examined in game theory where, starting from the well known rock-paper-scissor game, several other kinds of strategic interactions involving more than two choices are examined. In this paper we investigate how the dynamics evolve introducing one more option in binary choice games with externalities. The dynamics we obtain are always in a stable regime, that is, the structurally stable dynamics are only attracting cycles, but of any possible positive integer as period. We show that, depending on the structure of the game, the dynamics can be quite different from those existing when considering binary choices. The bifurcation structure, due to border collisions, is explained, showing the existence of so-called big-bang bifurcation points.
Invited review article: The Josephson bifurcation amplifier.
Vijay, R; Devoret, M H; Siddiqi, I
2009-11-01
We review the theory, fabrication, and implementation of the Josephson bifurcation amplifier (JBA). At the core of the JBA is a nonlinear oscillator based on a reactively shunted Josephson junction. A weak input signal to the amplifier couples to the junction critical current I(0) and results in a dispersive shift in the resonator plasma frequency omega(p). This shift is enhanced by biasing the junction with a sufficiently strong microwave current I(rf) to access the nonlinear regime where omega(p) varies with I(rf). For a drive frequency omega(d) such that Omega=2Q(1-omega(d)/omega(p))>3, the oscillator enters the bistable regime where two nondissipative dynamical states O(L) and O(H), which differ in amplitude and phase, can exist. The sharp I(0) dependent transition from O(L) to O(H) forms the basis for a sensitive digital threshold amplifier. In the vicinity of the bistable regime (Omegaamplifier performance and discuss two specific applications--the readout of superconducting qubits (digital mode) and dispersive microwave magnetometry (analog mode).
Quantum entanglement and fixed-point bifurcations
International Nuclear Information System (INIS)
Hines, Andrew P.; McKenzie, Ross H.; Milburn, G.J.
2005-01-01
How does the classical phase-space structure for a composite system relate to the entanglement characteristics of the corresponding quantum system? We demonstrate how the entanglement in nonlinear bipartite systems can be associated with a fixed-point bifurcation in the classical dynamics. Using the example of coupled giant spins we show that when a fixed point undergoes a supercritical pitchfork bifurcation, the corresponding quantum state--the ground state--achieves its maximum amount of entanglement near the critical point. We conjecture that this will be a generic feature of systems whose classical limit exhibits such a bifurcation
Bifurcation control of subsynchronous resonance using TCSC
Alomari, Majdi M.; Zhu, Jian Guo
2011-05-01
This paper presents the use of Thyristor-Controlled Series Capacitor (TCSC) to control bifurcations of subsynchronous resonance (SSR) in multimachine power system. The modified second system of the IEEE second benchmark model of subsynchronous resonance is considered. The dynamics of the damper windings, automatic voltage regulator (AVR), and power system stabilizer (PSS) on SSR in power system are included. In the case of neglecting TCSC, the results show that the operating point of the system loses stability via subcritical Hopf bifurcation. When we add TCSC to the system, all bifurcations are eliminated. Therefore, the Thyristor-Controlled compensated system never loses stability at any realistic firing angle.
CR-Calculus and adaptive array theory applied to MIMO random vibration control tests
Musella, U.; Manzato, S.; Peeters, B.; Guillaume, P.
2016-09-01
Performing Multiple-Input Multiple-Output (MIMO) tests to reproduce the vibration environment in a user-defined number of control points of a unit under test is necessary in applications where a realistic environment replication has to be achieved. MIMO tests require vibration control strategies to calculate the required drive signal vector that gives an acceptable replication of the target. This target is a (complex) vector with magnitude and phase information at the control points for MIMO Sine Control tests while in MIMO Random Control tests, in the most general case, the target is a complete spectral density matrix. The idea behind this work is to tailor a MIMO random vibration control approach that can be generalized to other MIMO tests, e.g. MIMO Sine and MIMO Time Waveform Replication. In this work the approach is to use gradient-based procedures over the complex space, applying the so called CR-Calculus and the adaptive array theory. With this approach it is possible to better control the process performances allowing the step-by-step Jacobian Matrix update. The theoretical bases behind the work are followed by an application of the developed method to a two-exciter two-axis system and by performance comparisons with standard methods.
Diffusion of innovations theory applied to global tobacco control treaty ratification.
Valente, Thomas W; Dyal, Stephanie R; Chu, Kar-Hai; Wipfli, Heather; Fujimoto, Kayo
2015-11-01
This study applies diffusion of innovations theory to understand network influences on country ratification of an international health treaty, the Framework Convention for Tobacco Control (FCTC). From 2003 to 2014 approximately 90% of United Nations member countries ratified the FCTC. We hypothesized that communication between tobacco control advocates on GLOBALink, a 7000-member online communication forum in existence from 1992 to 2012, would be associated with the timing of treaty ratification. We further hypothesized dynamic network influences such that external influence decreased over time, internal influence increased over time, and the role of opinion leader countries varied over time. In addition we develop two concepts: Susceptibility and influence that uncover the micro-level dynamics of network influence. Statistical analyses lend support to the influence of co-subscriptions on GLOBALink providing a conduit for inter-country influences on treaty ratification and some support for the dynamic hypotheses. Analyses of susceptibility and infection indicated particularly influential countries. These results have implications for the study of policy diffusion as well as dynamic models of behavior change. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Latent interaction effects in the theory of planned behaviour applied to quitting smoking.
Hukkelberg, Silje Sommer; Hagtvet, Knut A; Kovac, Velibor Bobo
2014-02-01
This study applies three latent interaction models in the theory of planned behaviour (TPB; Ajzen, 1988, Attitudes, personality, and behavior. Homewood, IL: Dorsey Press; Ajzen, 1991, Organ. Behav. Hum. Decis. Process., 50, 179) to quitting smoking: (1) attitude × perceived behavioural control on intention; (2) subjective norms (SN) × attitude on intention; and (3) perceived behavioural control × intention on quitting behaviour. The data derive from a longitudinal Internet survey of 939 smokers aged 15-74 over a period of 4 months. Latent interaction effects were estimated using the double-mean-centred unconstrained approach (Lin et al., 2010, Struct. Equ. Modeling, 17, 374) in LISREL. Attitude × SN and attitude × perceived behavioural control both showed a significant interaction effect on intention. No significant interaction effect was found for perceived behavioural control × intention on quitting. The latent interaction approach is a useful method for investigating specific conditions between TPB components in the context of quitting behaviour. Theoretical and practical implications of the results are discussed. © 2013 The British Psychological Society.
Directory of Open Access Journals (Sweden)
Abbas Moghimbeigi
2011-07-01
Full Text Available Background: Use of anabolic androgenic steroids (AAS has been associated with adversephysical and psychiatric effects and it is known as rising problem among youth people. Thisstudy was conducted to evaluate anabolic steroids preventative intervention efficiency amonggym users in Iran and theory of planned behaviour was applied as theoretical framework.Methods: Overall, 120 male gym users participated in this study as intervention and controlgroup. This was a longitudinal randomized pretest - posttest series control group design panelstudy to implement a behaviour modification based intervention to prevent AAS use. Cross -tabulation and t-test by using SPSS statistical package, version 13 was used for the statisticalanalysis.Results: It was found significant improvements in average response for knowledge about sideeffects of AAS (P<0.001, attitude toward, and intention not to use AAS. Additionally afterintervention, the rate of AAS and supplements use was decreased among intervention group.Conclusion: Comprehensive implementation against AAS abuse among gym users and adolescenceswould be effective to improve adolescents’ healthy behaviors and intend them notto use AAS.
Theory and design of broadband matching networks applied electricity and electronics
Chen, Wai-Kai
1976-01-01
Theory and Design of Broadband Matching Networks centers on the network theory and its applications to the design of broadband matching networks and amplifiers. Organized into five chapters, this book begins with a description of the foundation of network theory. Chapter 2 gives a fairly complete exposition of the scattering matrix associated with an n-port network. Chapter 3 considers the approximation problem along with a discussion of the approximating functions. Chapter 4 explains the Youla's theory of broadband matching by illustrating every phase of the theory with fully worked out examp
Eisenberg, Paul
2016-01-01
This study applies the prevailing scholarly theories of strategic management, employment decisions, cost accounting and share reward schemes to a panel of questions raised by Colin Drury (2012) in the case study of the fictitious company Integrated Technology Services (UK) Ltd., ITS (UK). The paper provides model answers which can be used when working with the case study at institutions of higher education. The merit of the work lies in three areas. First, it provides an overview of theories ...
Stability and bifurcation analysis in hematopoietic stem cell dynamics with multiple delays
Qu, Ying; Wei, Junjie; Ruan, Shigui
2010-10-01
This paper is devoted to the analysis of a maturity structured system of hematopoietic stem cell (HSC) populations in the bone marrow. The model is a system of differential equations with several time delays. We discuss the stability of equilibria and perform the analysis of Hopf bifurcation. More precisely, we first obtain a set of improved sufficient conditions ensuring the global asymptotical stability of the zero solution using the Lyapunov method and the embedding technique of asymptotically autonomous semiflows. Then we prove that there exists at least one positive periodic solution for the n-dimensional system as a time delay varies in some region. This result is established by combining Hopf bifurcation theory, the global Hopf bifurcation theorem due to Wu [J. Wu, Symmetric functional differential equations and neural networks with memory, Trans. Amer. Math. Soc. 350 (1998) 4799-4838], and a continuation theorem of coincidence degree theory. Some numerical simulations are also presented to illustrate the analytic results.
An effective correlated mean-field theory applied in the spin-1/2 Ising ferromagnetic model
Energy Technology Data Exchange (ETDEWEB)
Roberto Viana, J.; Salmon, Octávio R. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil); Ricardo de Sousa, J. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil); National Institute of Science and Technology for Complex Systems, Universidade Federal do Amazonas, 3000, Japiim, 69077-000 Manaus, AM (Brazil); Neto, Minos A.; Padilha, Igor T. [Universidade Federal do Amazonas – UFAM, Manaus 69077-000, AM (Brazil)
2014-11-15
We developed a new treatment for mean-field theory applied in spins systems, denominated effective correlated mean-field (ECMF). We apply this theory to study the spin-1/2 Ising ferromagnetic model with nearest-neighbor interactions on a square lattice. We use clusters of finite sizes and study the criticality of the ferromagnetic system, where we obtain a convergence of critical temperature for the value k{sub B}T{sub c}/J≃2.27905±0.00141. Also the behavior of magnetic and thermodynamic properties, using the condition of minimum energy of the physical system is obtained. - Highlights: • We developed spin models to study real magnetic systems. • We study the thermodynamic and magnetic properties of the ferromagnetism. • We enhanced a mean-field theory applied in spins models.
Directory of Open Access Journals (Sweden)
Huitao Zhao
2013-01-01
Full Text Available A ratio-dependent predator-prey model with two time delays is studied. By means of an iteration technique, sufficient conditions are obtained for the global attractiveness of the positive equilibrium. By comparison arguments, the global stability of the semitrivial equilibrium is addressed. By using the theory of functional equation and Hopf bifurcation, the conditions on which positive equilibrium exists and the quality of Hopf bifurcation are given. Using a global Hopf bifurcation result of Wu (1998 for functional differential equations, the global existence of the periodic solutions is obtained. Finally, an example for numerical simulations is also included.
Applying theory of planned behavior to predict exercise maintenance in sarcopenic elderly
Directory of Open Access Journals (Sweden)
Ahmad MH
2014-09-01
Full Text Available Mohamad Hasnan Ahmad,1 Suzana Shahar,2 Nur Islami Mohd Fahmi Teng,2 Zahara Abdul Manaf,2 Noor Ibrahim Mohd Sakian,3 Baharudin Omar41Centre of Nutrition Epidemiology Research, Institute of Public Health, Ministry of Health, Kuala Lumpur, Malaysia; 2Dietetics Program, 3Occupational Therapy Program, 4Department of Biomedical Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia Abstract: This study aimed to determine the factors associated with exercise behavior based on the theory of planned behavior (TPB among the sarcopenic elderly people in Cheras, Kuala Lumpur. A total of 65 subjects with mean ages of 67.5±5.2 (men and 66.1±5.1 (women years participated in this study. Subjects were divided into two groups: 1 exercise group (n=34; 25 men, nine women; and 2 the control group (n=31; 22 men, nine women. Structural equation modeling, based on TPB components, was applied to determine specific factors that most contribute to and predict actual behavior toward exercise. Based on the TPB’s model, attitude (ß=0.60 and perceived behavioral control (ß=0.24 were the major predictors of intention to exercise among men at the baseline. Among women, the subjective norm (ß=0.82 was the major predictor of intention to perform the exercise at the baseline. After 12 weeks, attitude (men’s, ß=0.68; women’s, ß=0.24 and subjective norm (men’s, ß=0.12; women’s, ß=0.87 were the predictors of the intention to perform the exercise. “Feels healthier with exercise” was the specific factor to improve the intention to perform and to maintain exercise behavior in men (ß=0.36 and women (ß=0.49. “Not motivated to perform exercise” was the main barrier among men’s intention to exercise. The intention to perform the exercise was able to predict actual behavior regarding exercise at the baseline and at 12 weeks of an intervention program. As a conclusion, TPB is a useful model to determine and
Bifurcation analysis of dengue transmission model in Baguio City, Philippines
Libatique, Criselda P.; Pajimola, Aprimelle Kris J.; Addawe, Joel M.
2017-11-01
In this study, we formulate a deterministic model for the transmission dynamics of dengue fever in Baguio City, Philippines. We analyzed the existence of the equilibria of the dengue model. We computed and obtained conditions for the existence of the equilibrium states. Stability analysis for the system is carried out for disease free equilibrium. We showed that the system becomes stable under certain conditions of the parameters. A particular parameter is taken and with the use of the Theory of Centre Manifold, the proposed model demonstrates a bifurcation phenomenon. We performed numerical simulation to verify the analytical results.
International Nuclear Information System (INIS)
Hajihosseini, Amirhossein; Maleki, Farzaneh; Rokni Lamooki, Gholam Reza
2011-01-01
Highlights: → We construct a recurrent neural network by generalizing a specific n-neuron network. → Several codimension 1 and 2 bifurcations take place in the newly constructed network. → The newly constructed network has higher capabilities to learn periodic signals. → The normal form theorem is applied to investigate dynamics of the network. → A series of bifurcation diagrams is given to support theoretical results. - Abstract: A class of recurrent neural networks is constructed by generalizing a specific class of n-neuron networks. It is shown that the newly constructed network experiences generic pitchfork and Hopf codimension one bifurcations. It is also proved that the emergence of generic Bogdanov-Takens, pitchfork-Hopf and Hopf-Hopf codimension two, and the degenerate Bogdanov-Takens bifurcation points in the parameter space is possible due to the intersections of codimension one bifurcation curves. The occurrence of bifurcations of higher codimensions significantly increases the capability of the newly constructed recurrent neural network to learn broader families of periodic signals.
Mermelstein, Robin J.; Revenson, Tracey A.
2013-01-01
Basic social psychological theories have much to contribute to our understanding of health problems and health-related behaviors and may provide potential avenues for intervention development. However, for these theories to have broader reach and applicability to the field of health psychology, more work needs to be done in integrating contexts into these theories and addressing more specifically their application across settings, behaviors, and populations. We argue that integration of these theories into a broader multi-disciplinary and multi-level ecological framework is needed to enhance their translation into real-world applications. To enhance this translation, we make several recommendations, including breaking down silos between disciplinary perspectives and enhancing bidirectional communication and translation; analyzing boundary conditions of theories; expanding research approaches to move outside the laboratory and maintain a focus on external validity; and conducting efficacy testing of theories with meaningful, relevant endpoints. PMID:23646843
Optimal polynomial theory applied to 0--350 MeV pp scattering
International Nuclear Information System (INIS)
Bergervoet, J.R.; van Campen, P.C.; Rijken, T.A.; de Swart, J.J.
1988-01-01
The optimal polynomial theory of Cutkosky, Deo, and Ciulli has been tested for its use in a multienergy phase-shift analysis of pp scattering data below T/sub lab/ = 350 MeV. The power of the optimal polynomial theory to predict higher partial wave phase parameters is investigated also for a realistic potential model; the Nijmegen potential. It is seen that the optimal polynomial theory has indeed predictive power whenever the phase parameters do not decrease too rapidly as a function of the orbital angular momentum. For a high-quality phase-shift analysis, the optimal polynomial theory does not predict F and G waves well enough. Therefore, these have to be parametrized. The predictive power of the optimal polynomial theory is then only used for higher partial waves. It appears that the Nijmegen potential tail contains valuable physical information beyond the optimal polynomial theory
Ortega, Johis; Huang, Shi; Prado, Guillermo
2012-01-03
HIV/AIDS is listed as one of the top 10 reasons for the death of Hispanics between the ages of 15 and 54 in the United States. This cross sectional, descriptive secondary study proposed that using both the systemic (ecodevelopmental) and the individually focused (theory of reasoned action) theories together would lead to an increased understanding of the risk and protective factors that influence HIV risk behaviors in this population. The sample consisted of 493 Hispanic adolescent 7th and 8th graders and their immigrant parents living in Miami, Florida. Structural Equation Modeling (SEM) was used for the data analysis. Family functioning emerged as the heart of the model, embedded within a web of direct and mediated relationships. The data support the idea that family can play a central role in the prevention of Hispanic adolescents' risk behaviors.
Sampling theory and automated simulations for vertical sections, applied to human brain.
Cruz-Orive, L M; Gelšvartas, J; Roberts, N
2014-02-01
In recent years, there have been substantial developments in both magnetic resonance imaging techniques and automatic image analysis software. The purpose of this paper is to develop stereological image sampling theory (i.e. unbiased sampling rules) that can be used by image analysts for estimating geometric quantities such as surface area and volume, and to illustrate its implementation. The methods will ideally be applied automatically on segmented, properly sampled 2D images - although convenient manual application is always an option - and they are of wide applicability in many disciplines. In particular, the vertical sections design to estimate surface area is described in detail and applied to estimate the area of the pial surface and of the boundary between cortex and underlying white matter (i.e. subcortical surface area). For completeness, cortical volume and mean cortical thickness are also estimated. The aforementioned surfaces were triangulated in 3D with the aid of FreeSurfer software, which provided accurate surface area measures that served as gold standards. Furthermore, a software was developed to produce digitized trace curves of the triangulated target surfaces automatically from virtual sections. From such traces, a new method (called the 'lambda method') is presented to estimate surface area automatically. In addition, with the new software, intersections could be counted automatically between the relevant surface traces and a cycloid test grid for the classical design. This capability, together with the aforementioned gold standard, enabled us to thoroughly check the performance and the variability of the different estimators by Monte Carlo simulations for studying the human brain. In particular, new methods are offered to split the total error variance into the orientations, sectioning and cycloid components. The latter prediction was hitherto unavailable--one is proposed here and checked by way of simulations on a given set of digitized
Applying theory of planned behavior in predicting of patient safety behaviors of nurses.
Javadi, Marzieh; Kadkhodaee, Maryam; Yaghoubi, Maryam; Maroufi, Maryam; Shams, Asadollah
2013-01-01
Patient safety has become a major concern throughout the world. It is the absence of preventable harm to a patient during the process of health care, ensuring safer care is an enormous challenge, psychosocial variables influences behaviors of human. The theory of planned behavior (TPB) is a well-validated behavioral decision-making model that has been used to predict social and health behaviors. This study is aimed to investigate predictors of nurse's patient safety intentions and behavior, using a TPB framework. Stratified sampling technique was used to choose 124 nurses who worked at the selected hospitals of Isfahan in 2011. Study tool was a questionnaire, designed by researchers team including 3 nurses a physician and a psychologist based on guideline of TPB model. Questionnaire Validity was confirmed by experts and its reliability was assessed by Cronbach's alpha as 0.87. Binary logistic regression analysis was performed to evaluate how well each TPB variables predicted the variance in patient safety behavior. Analyzing was done by SPSS18. Finding revealed that "normative beliefs" had the greatest influence on nurses intention to implement patient safety behaviors. Analyzing data by hospital types and workplace wards showed that both in public and private hospitals normative beliefs has affected safety behaviors of nurses more than other variables. Also in surgical wards, nurses behaviors have been affected by "control beliefs" and in medical wards by normative beliefs. Normative beliefs, and subjective norms were the most influential factor of safety behavior of nurses in this study. Considering the role of cultural context in these issues, it seemseducation of managers and top individuals about patient safety and its importance is a priority also control believes were another important predicting factor of behavior in surgical wards and intensive care units. Regarding the complexity of work in these spaces, applying medical guidelines and effective
Applying theory of planned behavior to predict exercise maintenance in sarcopenic elderly.
Ahmad, Mohamad Hasnan; Shahar, Suzana; Teng, Nur Islami Mohd Fahmi; Manaf, Zahara Abdul; Sakian, Noor Ibrahim Mohd; Omar, Baharudin
2014-01-01
This study aimed to determine the factors associated with exercise behavior based on the theory of planned behavior (TPB) among the sarcopenic elderly people in Cheras, Kuala Lumpur. A total of 65 subjects with mean ages of 67.5±5.2 (men) and 66.1±5.1 (women) years participated in this study. Subjects were divided into two groups: 1) exercise group (n=34; 25 men, nine women); and 2) the control group (n=31; 22 men, nine women). Structural equation modeling, based on TPB components, was applied to determine specific factors that most contribute to and predict actual behavior toward exercise. Based on the TPB's model, attitude (β=0.60) and perceived behavioral control (β=0.24) were the major predictors of intention to exercise among men at the baseline. Among women, the subjective norm (β=0.82) was the major predictor of intention to perform the exercise at the baseline. After 12 weeks, attitude (men's, β=0.68; women's, β=0.24) and subjective norm (men's, β=0.12; women's, β=0.87) were the predictors of the intention to perform the exercise. "Feels healthier with exercise" was the specific factor to improve the intention to perform and to maintain exercise behavior in men (β=0.36) and women (β=0.49). "Not motivated to perform exercise" was the main barrier among men's intention to exercise. The intention to perform the exercise was able to predict actual behavior regarding exercise at the baseline and at 12 weeks of an intervention program. As a conclusion, TPB is a useful model to determine and to predict maintenance of exercise in the sarcopenic elderly.
Item response theory analysis applied to the Spanish version of the Personal Outcomes Scale.
Guàrdia-Olmos, J; Carbó-Carreté, M; Peró-Cebollero, M; Giné, C
2017-11-01
The study of measurements of quality of life (QoL) is one of the great challenges of modern psychology and psychometric approaches. This issue has greater importance when examining QoL in populations that were historically treated on the basis of their deficiency, and recently, the focus has shifted to what each person values and desires in their life, as in cases of people with intellectual disability (ID). Many studies of QoL scales applied in this area have attempted to improve the validity and reliability of their components by incorporating various sources of information to achieve consistency in the data obtained. The adaptation of the Personal Outcomes Scale (POS) in Spanish has shown excellent psychometric attributes, and its administration has three sources of information: self-assessment, practitioner and family. The study of possible congruence or incongruence of observed distributions of each item between sources is therefore essential to ensure a correct interpretation of the measure. The aim of this paper was to analyse the observed distribution of items and dimensions from the three Spanish POS information sources cited earlier, using the item response theory. We studied a sample of 529 people with ID and their respective practitioners and family member, and in each case, we analysed items and factors using Samejima's model of polytomic ordinal scales. The results indicated an important number of items with differential effects regarding sources, and in some cases, they indicated significant differences in the distribution of items, factors and sources of information. As a result of this analysis, we must affirm that the administration of the POS, considering three sources of information, was adequate overall, but a correct interpretation of the results requires that it obtain much more information to consider, as well as some specific items in specific dimensions. The overall ratings, if these comments are considered, could result in bias. © 2017
Applying Portfolio Theory to EU Electricity Planning and Policy-Making
Energy Technology Data Exchange (ETDEWEB)
Awerbuch, Shimon; Berger, Martin
2003-02-01
This study introduces mean-variance portfolio theory and evaluates its potential application to the development of efficient (optimal) European Union (EU-15) generating portfolios that enhance energy security and diversification objectives. The analysis extends to European countries the previous work done by Awerbuch in the US, and applies a significantly more detailed portfolio model that reflects the risk of the relevant generating cost streams: fuel, operation and maintenance and construction period costs. It illustrates the portfolio effects of different generating mixes. The study offers preliminary findings on the effects of including more renewable energy sources in the typical EU portfolio mix and suggests interesting directions for further study. The study arises from the perception that these standard, finance-oriented analyses may offer valuable enhancements to energy planning, and concepts of energy security and diversity. Clearly the combination of better portfolio construction and more accurate pricing should lead to more optimal decisions in the round. This study, therefore, represents an effort to complement traditional approaches and point researchers and planners into new territory. The results generally indicate that the existing and projected EU generating mixes are sub optimal - though slightly - from a risk-return perspective, which implies that feasible portfolios with lower cost and risk exist. These can be developed by adjusting the conventional mix and by including larger shares of wind or similar renewable technologies. The results of the portfolio analysis suggest that fixed cost technologies such as renewables must be a part of any efficient generating portfolio. Our assessment of all technologies is limited to risk and cost measures, although other benefits, including low externality costs and sustainability, are often cited for renewables.
Vlah, Zvonimir; Seljak, Uroš; McDonald, Patrick; Okumura, Teppei; Baldauf, Tobias
2012-11-01
We develop a perturbative approach to redshift space distortions (RSD) using the phase space distribution function approach and apply it to the dark matter redshift space power spectrum and its moments. RSD can be written as a sum over density weighted velocity moments correlators, with the lowest order being density, momentum density and stress energy density. We use standard and extended perturbation theory (PT) to determine their auto and cross correlators, comparing them to N-body simulations. We show which of the terms can be modeled well with the standard PT and which need additional terms that include higher order corrections which cannot be modeled in PT. Most of these additional terms are related to the small scale velocity dispersion effects, the so called finger of god (FoG) effects, which affect some, but not all, of the terms in this expansion, and which can be approximately modeled using a simple physically motivated ansatz such as the halo model. We point out that there are several velocity dispersions that enter into the detailed RSD analysis with very different amplitudes, which can be approximately predicted by the halo model. In contrast to previous models our approach systematically includes all of the terms at a given order in PT and provides a physical interpretation for the small scale dispersion values. We investigate RSD power spectrum as a function of μ, the cosine of the angle between the Fourier mode and line of sight, focusing on the lowest order powers of μ and multipole moments which dominate the observable RSD power spectrum. Overall we find considerable success in modeling many, but not all, of the terms in this expansion. This is similar to the situation in real space, but predicting power spectrum in redshift space is more difficult because of the explicit influence of small scale dispersion type effects in RSD, which extend to very large scales.
Rayleigh theory of ultrasound scattering applied to liquid-filled contrast nanoparticles.
Flegg, M B; Poole, C M; Whittaker, A K; Keen, I; Langton, C M
2010-06-07
We present a novel modified theory based upon Rayleigh scattering of ultrasound from composite nanoparticles with a liquid core and solid shell. We derive closed form solutions to the scattering cross-section and have applied this model to an ultrasound contrast agent consisting of a liquid-filled core (perfluorooctyl bromide, PFOB) encapsulated by a polymer shell (poly-caprolactone, PCL). Sensitivity analysis was performed to predict the dependence of the scattering cross-section upon material and dimensional parameters. A rapid increase in the scattering cross-section was achieved by increasing the compressibility of the core, validating the incorporation of high compressibility PFOB; the compressibility of the shell had little impact on the overall scattering cross-section although a more compressible shell is desirable. Changes in the density of the shell and the core result in predicted local minima in the scattering cross-section, approximately corresponding to the PFOB-PCL contrast agent considered; hence, incorporation of a lower shell density could potentially significantly improve the scattering cross-section. A 50% reduction in shell thickness relative to external radius increased the predicted scattering cross-section by 50%. Although it has often been considered that the shell has a negative effect on the echogeneity due to its low compressibility, we have shown that it can potentially play an important role in the echogeneity of the contrast agent. The challenge for the future is to identify suitable shell and core materials that meet the predicted characteristics in order to achieve optimal echogenity.
Sharma, Manoj; Khubchandani, Jagdish; Nahar, Vinayak K
2017-01-01
Background: Smoking continues to be a public health problem worldwide. Smoking and tobacco use are associated with cardiovascular diseases that include coronary heart disease, atherosclerosis, cerebrovascular disease, and abdominal aortic aneurysm. Programs for quitting smoking have played a significant role in reduction of smoking in the United States. The smoking cessation interventions include counseling, nicotine replacement therapy, buproprion therapy, and varenicline therapy. The success rates with each of these approaches vary with clear need for improvement. Moreover, there is a need for a robust theory that can guide smoking cessation counseling interventions and increase the success rates. A fourth generation approach using multi-theory model (MTM) of health behavior change is introduced in this article for smoking cessation. An approach for developing and evaluating an intervention for smoking cessation is presented along with a measurement tool. Methods: A literature review reifying the MTM of health behavior change for smoking cessation has been presented. An instrument designed to measure constructs of MTM and associated smoking cessation behavior has been developed. Results: The instrument developed is available for validation, reliability and prediction study pertaining to smoking cessation. The intervention is available for testing in a randomized control trial involving smokers. Conclusion: MTM is a robust theory that holds promise for testing and application to smoking cessation.
Bridging the Gap in Port Security; Network Centric Theory Applied to Public/Private Collaboration
National Research Council Canada - National Science Library
Wright, Candice L
2007-01-01
...." Admiral Thad Allen, 2007 The application of Network Centric Warfare theory enables all port stakeholders to better prepare for a disaster through increased information sharing and collaboration...
Applying Sociocultural Theory to Teaching Statistics for Doctoral Social Work Students
Mogro-Wilson, Cristina; Reeves, Michael G.; Charter, Mollie Lazar
2015-01-01
This article describes the development of two doctoral-level multivariate statistics courses utilizing sociocultural theory, an integrative pedagogical framework. In the first course, the implementation of sociocultural theory helps to support the students through a rigorous introduction to statistics. The second course involves students…
Pratt, Cornelius B.
1994-01-01
Links ethical theories to the management of the product recall of the Perrier Group of America. Argues for a nonsituational theory-based eclectic approach to ethics in public relations to enable public relations practitioners, as strategic communication managers, to respond effectively to potentially unethical organizational actions. (SR)
Bustillos, Antonio; Silvan-Ferrero, Maria del Prado
2013-01-01
The aim of this work was to study attitudes toward people with disabilities from the viewpoint of the integrated threat theory of prejudice. This theory postulates that threat may cause negative attitudes toward a group and posits that such threat may come from different sources. To test this model, a study was carried out with high school…
McKown, Clark
2005-01-01
Several school-based racial prejudice-reduction interventions have demonstrated some benefit. Ecological theory serves as a framework within which to understand the limits and to enhance the efficacy of prejudice-reduction interventions. Using ecological theory, this article examines three prejudice-reduction approaches, including social cognitive…
Dongyu, Zhang; Fanyu, B.; Wanyi, Du
2013-01-01
This paper discusses the sociocultural theory (SCT). In particular, three significant concepts of Vyogtsky's theory: self-regulation, the Zone of Proximal Development (ZPD), and scaffolding all of which have been discussed in numerous second language acquisition (SLA) and second language learning (SLL) research papers. These concepts lay the…
Set Theory Applied to Uniquely Define the Inputs to Territorial Systems in Emergy Analyses
The language of set theory can be utilized to represent the emergy involved in all processes. In this paper we use set theory in an emergy evaluation to ensure an accurate representation of the inputs to territorial systems. We consider a generic territorial system and we describ...
Katsarou-Tzeveleki, Stella
on the search for the exception or difference in material culture as the secure way to describe any certain cultural identity. When Knapp applies his theory to Cyprus, he divides the period under examination into two general chronological horizons, and introduces two interesting neologisms: the prehistoric Bronze Age (down to 1650) and the protohistoric Bronze Age (1650-10th century BC), the conventional boundary between them being the appearance of literary sources. Unfortunately, we find that there is no reference to the Chalcolithic, Neolithic and Epipalaeolithic prehistory of Cyprus, since he axiomatically takes the end of the Cypriot Chalcolithic (the Philia culture) as a point of catalytic social change. I believe, however, that one thought (and here we have a challenge to future research) is missing: the contribution made by the earlier societies of the island to the formation of its later tradition, since Knapp himself repeatedly accepts in his book the historical-comparative dimension of identity in the long term, and ultimately resorts to hybridization, in which the local tradition contributes equally as the intrusive factors do. I welcome the distinction of the Bronze Age in prehistoric and protohistoric. Concerning the term protohistory, familiar in Cypriot archaeology since Peltenburg (1982), I strongly recommend it to Greek archaeologists who have enough textual evidence to finally decide to distinguish the proto-literary Late Bronze Age from the vast depths of the Early-Middle Bronze Age, Neolithic and Palaeolithic prehistory of Greece. As for the prehistoric Bronze Age of Cyprus (Late Chalcolithic-1650 BC), Knapp adopts a social/socio-economic approach that involves aspects of elite formation, copper production and exchange, gender representations and individuality. He eschews references to evolutionary typologies and revises Webb and Frankel's (1999) theory of direct migration or colonization from Anatolia, in favour of hybridization, repeating that
Hopf bifurcations in a fractional reaction–diffusion model for the ...
African Journals Online (AJOL)
The phenomenon of hopf bifurcation has been well-studied and applied to many physical situations to explain behaviour of solutions resulting from differential and partial differential equations. This phenomenon is applied to a fractional reaction diffusion model for tumor invasion and development. The result suggests that ...
Kwon, Nahyun
2017-01-01
Introduction: This study was conducted to investigate the characteristics of research and information activities of laboratory scientists in different work positions throughout a research lifecycle. Activity theory was applied as the conceptual and analytical framework. Method: Taking a qualitative research approach, in-depth interviews and field…
Hartmann, Anita
2011-01-01
In the current economic climate, many colleges and universities face similar challenges: the need to increase external sponsorship for research activities and the need to benefit from additional indirect cost recovery. Preparing funding proposals for submission to sponsors is a faculty behavior that can be modified by applying behavioral theory to…
Dijkstra, T.; Meulenberg, M.T.G.; Tilburg, van A.
2001-01-01
This article shows that marketing channel theory, which has been extensively applied in developed countries, can also be of great value to the developing world. Notably, the channel approach makes it possible to explain the number of trade levels observed in food marketing systems. We propose here a
Schneider, Claudia; Arnot, Madeleine
2018-01-01
This article explores the modes of school communication associated with language and cultural diversity, demonstrating how organisational communication theory can be applied to the analysis of schools' communication responses to the presence of pupils who have English as an additional language (EAL). The article highlights three analytical…
Snitker-Magin, Mikael C.
2010-01-01
The purpose of the study was to apply Bandura's self-efficacy theory to understanding the behavior of college students with disabilities in requesting accommodations. Students with disabilities were recruited from 20 two-year and four-year postsecondary institutions by asking student disabilities services staff to forward an email invitation to…
Briggs, Harold Eugene; Sharkey, Caroline; Briggs, Adam Christopher
2016-01-01
In this article the authors tie the emergence of an empirical practice research culture, which enabled the rise in evidence-based practice in social work to the introduction of applied behavior analysis and behavioral theory to social work practice and research. The authors chronicle the: (1) scientific foundations of social work, (2) influence and push by corporatized university cultures for higher scholarship productivity among faculty, (3) significance of theory in general, (4) importance of behavioral theory in particular as a major trigger of the growth in research on effective social work practice approaches, and (5) commonalities between applied behavior analysis and evidence-based practice. The authors conclude with implications for addressing the dual challenges of building an enhanced research culture in schools of social work and the scholarship of transferring practice research to adoption in real world practice settings.
Hopf bifurcation in a partial dependent predator-prey system with delay
International Nuclear Information System (INIS)
Zhao Huitao; Lin Yiping
2009-01-01
In this paper, a partial dependent predator-prey model with time delay is studied by using the theory of functional differential equation and Hassard's method, the condition on which positive equilibrium exists and Hopf bifurcation occurs are given. Finally, numerical simulations are performed to support the analytical results, and the chaotic behaviors are observed.
Zhang, Yongfang; Hei, Di; Lü, Yanjun; Wang, Quandai; Müller, Norbert
2014-03-01
Axial-grooved gas-lubricated journal bearings have been widely applied to precision instrument due to their high accuracy, low friction, low noise and high stability. The rotor system with axial-grooved gas-lubricated journal bearing support is a typical nonlinear dynamic system. The nonlinear analysis measures have to be adopted to analyze the behaviors of the axial-grooved gas-lubricated journal bearing-rotor nonlinear system as the linear analysis measures fail. The bifurcation and chaos of nonlinear rotor system with three axial-grooved gas-lubricated journal bearing support are investigated by nonlinear dynamics theory. A time-dependent mathematical model is established to describe the pressure distribution in the axial-grooved compressible gas-lubricated journal bearing. The time-dependent compressible gas-lubricated Reynolds equation is solved by the differential transformation method. The gyroscopic effect of the rotor supported by gas-lubricated journal bearing with three axial grooves is taken into consideration in the model of the system, and the dynamic equation of motion is calculated by the modified Wilson- θ-based method. To analyze the unbalanced responses of the rotor system supported by finite length gas-lubricated journal bearings, such as bifurcation and chaos, the bifurcation diagram, the orbit diagram, the Poincaré map, the time series and the frequency spectrum are employed. The numerical results reveal that the nonlinear gas film forces have a significant influence on the stability of rotor system and there are the rich nonlinear phenomena, such as the periodic, period-doubling, quasi-periodic, period-4 and chaotic motion, and so on. The proposed models and numerical results can provide a theoretical direction to the design of axial-grooved gas-lubricated journal bearing-rotor system.
Krantz, Richard; Douthett, Jack
2009-10-01
Although it is common practice to borrow tools from mathematics to apply to physics or music, it is unusual to use tools developed in music theory to mathematically describe physical phenomena. So called ``Maximally Even Set'' theory fits this unusual case. In this poster, we summarize, by example, the theory of Maximally Even (ME) sets and show how this formalism leads to the distribution of black and white keys on the piano keyboard. We then show how ME sets lead to a generalization of the well-known ``Cycle-of-Fifths'' in music theory. Subsequently, we describe ordering in one-dimensional spin-1/2 anti-ferromagnets using ME sets showing that this description leads to a fractal ``Devil's Staircase'' magnetic phase diagram. Finally, we examine an extension of ME sets, ``Iterated Maximally Even'' sets that describes chord structure in music.
DEFF Research Database (Denmark)
Behan, Miles W; Holm, Niels R; Curzen, Nicholas P
2011-01-01
Background— Controversy persists regarding the correct strategy for bifurcation lesions. Therefore, we combined the patient-level data from 2 large trials with similar methodology: the NORDIC Bifurcation Study (NORDIC I) and the British Bifurcation Coronary Study (BBC ONE). Methods and Results— B...
Applying equity theory to staff working with individuals with intellectual disabilities.
Disley, Philip; Hatton, Chris; Dagnan, Dave
2009-03-01
This paper provides an overview of the empirical research on equity theory amongst staff working in services for individuals with intellectual disabilities (ID). Relevant articles were identified by using the PsycINFO computerised database and by conducting manual searches of reference lists. Six studies were identified and reviewed. Staff often report that they feel under-benefited in their work-based relationships. Associations were found between staff equity perceptions and staff outcomes such as burnout, absenteeism and intention to leave. Previous research findings on staff outcomes are discussed within the context of equity theory. The implications of staff equity perceptions for ID services are discussed and possible directions for future research are forwarded. It is suggested that equity theory may have some utility as a theoretical starting point from which to develop a comprehensive theory to integrate various strands of research on staffing.
Applying the Apos Theory to Improve Students Ability to Prove in Elementary Abstract Algebra
Arnawa, I Made; sumarno, Utari; Kartasasmita, Bana; Baskoro, Edy Tri
2007-01-01
This study is a quasi-experimental nonrandomized pretest-posttest control group design. The experiment group is treated by APOS theory instruction (APOS),that implements four characteristics of APOS theory, (1) mathematical knowledge was constructed through mental construction: actions, processes, objects, and organizing these in schemas, (2) using computer, (3) using cooperative learning groups, and (4) using ACE teaching cycle (activities, class discussion, and exercise). The control group ...
Applying Modern Stage Theory to Mauritania: A Prescription to Encourage Entrepreneurship
2014-12-01
STAGE THEORY TO MAURITANIA: A PRESCRIPTION TO ENCOURAGE ENTREPRENEURSHIP by Jennifer M. Warren December 2014 Thesis Advisor: Robert E...PRESCRIPTION TO ENCOURAGE ENTREPRENEURSHIP 5. FUNDING NUMBERS 6. AUTHOR(S) Jennifer M. Warren 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval...a chapter in which Dr. Looney relates modern stage theory to emerging economies. With an understanding that entrepreneurship is key for sustained
Analytical methods applied to the study of lattice gauge and spin theories
International Nuclear Information System (INIS)
Moreo, Adriana.
1985-01-01
A study of interactions between quarks and gluons is presented. Certain difficulties of the quantum chromodynamics to explain the behaviour of quarks has given origin to the technique of lattice gauge theories. First the phase diagrams of the discrete space-time theories are studied. The analysis of the phase diagrams is made by numerical and analytical methods. The following items were investigated and studied: a) A variational technique was proposed to obtain very accurated values for the ground and first excited state energy of the analyzed theory; b) A mean-field-like approximation for lattice spin models in the link formulation which is a generalization of the mean-plaquette technique was developed; c) A new method to study lattice gauge theories at finite temperature was proposed. For the first time, a non-abelian model was studied with analytical methods; d) An abelian lattice gauge theory with fermionic matter at the strong coupling limit was analyzed. Interesting results applicable to non-abelian gauge theories were obtained. (M.E.L.) [es
International Nuclear Information System (INIS)
Wang Shunnan
1990-01-01
The fields of theoretical evaluation method of nuclear data calculations and applied nuclear reaction theory research were described briefly. A global review of phenomenological and microscopic optical potential in nuclear data evaluation of 14 natural elements in the energy range of 0.1-24 MeV has been done. The nuclear fission is studied based on a new fission mechanism-the fission diffusion model. This model was proposed to explain the enhancement of neutron emission in heavy ion collisions
Bifurcations of Tumor-Immune Competition Systems with Delay
Directory of Open Access Journals (Sweden)
Ping Bi
2014-01-01
Full Text Available A tumor-immune competition model with delay is considered, which consists of two-dimensional nonlinear differential equation. The conditions for the linear stability of the equilibria are obtained by analyzing the distribution of eigenvalues. General formulas for the direction, period, and stability of the bifurcated periodic solutions are given for codimension one and codimension two bifurcations, including Hopf bifurcation, steady-state bifurcation, and B-T bifurcation. Numerical examples and simulations are given to illustrate the bifurcations analysis and obtained results.
Directory of Open Access Journals (Sweden)
Shweiki E
2015-04-01
Full Text Available Ehyal Shweiki,1 Niels D Martin,2 Alec C Beekley,1 Jay S Jenoff,1 George J Koenig,1 Kris R Kaulback,1 Gary A Lindenbaum,1 Pankaj H Patel,1 Matthew M Rosen,1 Michael S Weinstein,1 Muhammad H Zubair,2 Murray J Cohen1 1Department of Surgery, Thomas Jefferson University Hospital, Philadelphia, PA, USA; 2Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA Abstract: Medical resident education in the United States has been a matter of national priority for decades, exemplified initially through the Liaison Committee for Graduate Medical Education and then superseded by the Accreditation Council for Graduate Medical Education. A recent Special Report in the New England Journal of Medicine, however, has described resident educational programs to date as prescriptive, noting an absence of innovation in education. Current aims of contemporary medical resident education are thus being directed at ensuring quality in learning as well as in patient care. Achievement and work-motivation theories attempt to explain people's choice, performance, and persistence in tasks. Expectancy Theory as one such theory was reviewed in detail, appearing particularly applicable to surgical residency training. Correlations between Expectancy Theory as a work-motivation theory and residency education were explored. Understanding achievement and work-motivation theories affords an opportunity to gain insight into resident motivation in training. The application of Expectancy Theory in particular provides an innovative perspective into residency education. Afforded are opportunities to promote the development of programmatic methods facilitating surgical resident motivation in education. Keywords: learning, education, achievement
Bifurcation of Periodic Solutions of the Mackey– Glass Equation
E. P. Kubyshkin; A. R. Moryakova
2016-01-01
We study the bifurcation of the equilibrium states of periodic solutions for the Mackey– Glass equation. This equation is considered as a mathematical model of changes in the density of white blood cells. The equation written in dimensionless variables contains a small parameter at the derivative, which makes it singular. We applied the method of uniform normalization, which allows us to reduce the study of the solutions behavior in the neighborhood of the equilibrium state to the analysis of...
Stability and Bifurcation Analysis for a Predator-Prey Model with Discrete and Distributed Delay
Directory of Open Access Journals (Sweden)
Ruiqing Shi
2013-01-01
Full Text Available We propose a two-dimensional predatory-prey model with discrete and distributed delay. By the use of a new variable, the original two-dimensional system transforms into an equivalent three-dimensional system. Firstly, we study the existence and local stability of equilibria of the new system. And, by choosing the time delay τ as a bifurcation parameter, we show that Hopf bifurcation can occur as the time delay τ passes through some critical values. Secondly, by the use of normal form theory and central manifold argument, we establish the direction and stability of Hopf bifurcation. At last, an example with numerical simulations is provided to verify the theoretical results. In addition, some simple discussion is also presented.
Hopf Bifurcation Analysis for a Stochastic Discrete-Time Hyperchaotic System
Directory of Open Access Journals (Sweden)
Jie Ran
2015-01-01
Full Text Available The dynamics of a discrete-time hyperchaotic system and the amplitude control of Hopf bifurcation for a stochastic discrete-time hyperchaotic system are investigated in this paper. Numerical simulations are presented to exhibit the complex dynamical behaviors in the discrete-time hyperchaotic system. Furthermore, the stochastic discrete-time hyperchaotic system with random parameters is transformed into its equivalent deterministic system with the orthogonal polynomial theory of discrete random function. In addition, the dynamical features of the discrete-time hyperchaotic system with random disturbances are obtained through its equivalent deterministic system. By using the Hopf bifurcation conditions of the deterministic discrete-time system, the specific conditions for the existence of Hopf bifurcation in the equivalent deterministic system are derived. And the amplitude control with random intensity is discussed in detail. Finally, the feasibility of the control method is demonstrated by numerical simulations.
Barnett, William A.; Duzhak, Evgeniya Aleksandrovna
2008-06-01
Grandmont [J.M. Grandmont, On endogenous competitive business cycles, Econometrica 53 (1985) 995-1045] found that the parameter space of the most classical dynamic models is stratified into an infinite number of subsets supporting an infinite number of different kinds of dynamics, from monotonic stability at one extreme to chaos at the other extreme, and with many forms of multiperiodic dynamics in between. The econometric implications of Grandmont’s findings are particularly important, if bifurcation boundaries cross the confidence regions surrounding parameter estimates in policy-relevant models. Stratification of a confidence region into bifurcated subsets seriously damages robustness of dynamical inferences. Recently, interest in policy in some circles has moved to New-Keynesian models. As a result, in this paper we explore bifurcation within the class of New-Keynesian models. We develop the econometric theory needed to locate bifurcation boundaries in log-linearized New-Keynesian models with Taylor policy rules or inflation-targeting policy rules. Central results needed in this research are our theorems on the existence and location of Hopf bifurcation boundaries in each of the cases that we consider.
Barnett, William H; Cymbalyuk, Gennady S
2014-01-01
The dynamics of individual neurons are crucial for producing functional activity in neuronal networks. An open question is how temporal characteristics can be controlled in bursting activity and in transient neuronal responses to synaptic input. Bifurcation theory provides a framework to discover generic mechanisms addressing this question. We present a family of mechanisms organized around a global codimension-2 bifurcation. The cornerstone bifurcation is located at the intersection of the border between bursting and spiking and the border between bursting and silence. These borders correspond to the blue sky catastrophe bifurcation and the saddle-node bifurcation on an invariant circle (SNIC) curves, respectively. The cornerstone bifurcation satisfies the conditions for both the blue sky catastrophe and SNIC. The burst duration and interburst interval increase as the inverse of the square root of the difference between the corresponding bifurcation parameter and its bifurcation value. For a given set of burst duration and interburst interval, one can find the parameter values supporting these temporal characteristics. The cornerstone bifurcation also determines the responses of silent and spiking neurons. In a silent neuron with parameters close to the SNIC, a pulse of current triggers a single burst. In a spiking neuron with parameters close to the blue sky catastrophe, a pulse of current temporarily silences the neuron. These responses are stereotypical: the durations of the transient intervals-the duration of the burst and the duration of latency to spiking-are governed by the inverse-square-root laws. The mechanisms described here could be used to coordinate neuromuscular control in central pattern generators. As proof of principle, we construct small networks that control metachronal-wave motor pattern exhibited in locomotion. This pattern is determined by the phase relations of bursting neurons in a simple central pattern generator modeled by a chain of
Lagrangian neoclassical transport theory applied to the region near the magnetic axis
Energy Technology Data Exchange (ETDEWEB)
Satake, Shinsuke [The Graduate Univ. for Advanced Studies, Dept. of Fusion Science, Toki, Gifu (Japan); Okamoto, Masao; Sugama, Hideo [National Inst. for Fusion Science, Toki, Gifu (Japan)
2002-06-01
Neoclassical transport theory around the magnetic axis of a tokamak is studied, in which relatively wide ''potato'' orbits play an important role in transport. Lagrangian formulation of transport theory, which has been investigated to reflect finiteness of guiding-center orbit widths to transport equations, is developed in order to analyze neoclassical transport near the axis for a low-collisionality plasma. The treatment of self-collision term in Lagrangian formulation is revised to retain momentum conservation property of it. With directly reflecting the orbital properties of all the types of orbits in calculation, the ion thermal conductivity around the axis is found to decrease than from that predicted by conventional neoclassical theory. This result supports recent numerical simulations which show the reduction of thermal conductivity near the magnetic axis. (author)
Applying the expectancy disconfirmation and regret theories to online consumer behavior.
Liao, Chechen; Liu, Chuang-Chun; Liu, Yu-Ping; To, Pui-Lai; Lin, Hong-Nan
2011-04-01
This study synthesizes the expectancy disconfirmation theory with empirical theories pertaining to customer regret in an e-commerce environment. The study begins by examining the roles that information quality (IQ), system quality (SYQ), and service quality (SEQ) play in determining customer regret and satisfaction. Then the consequences of regret and satisfaction on reuse intention are examined. Survey data collected from 445 respondents are analyzed using structural equation modeling with partial least squares (PLS-Graph 3.0) to provide support for the hypothesized links. Results show that IQ disconfirmation, SYQ disconfirmation and SEQ disconfirmation are related to regret and satisfaction. Both regret and satisfaction are related to reuse intention. In addition, satisfaction mediates the effect of regret on reuse intention. Based on these results, implications for theory and practice are discussed.
Schumacher, Daniel J; Englander, Robert; Carraccio, Carol
2013-11-01
As a result of the paradigm shift to a competency-based framework, both self-directed lifelong learning and learner-centeredness have become essential tenets of medical education. In the competency-based framework, learners drive their own educational process, and both learners and teachers share the responsibility for the path and content of learning. This learner-centered emphasis requires each physician to develop and maintain lifelong learning skills, which the authors propose culminate in becoming a "master leaner." To better understand the development of these skills and the attainment of that goal, the authors explore how learning theories inform the development of master learners and how to translate these theories into practical strategies for the learner, the teacher, and the learning environment so as to optimize this development.The authors begin by exploring self-determination theory, which lays the groundwork for understanding the motivation to learn. They next consider the theories of cognitive load and situated cognition, which inform the optimal context and environment for learning. Building from this foundation, the authors consider key educational theories that affect learners' abilities to serve as primary drivers of their learning, including self-directed learning (SDL); the self-assessment skills necessary for SDL; factors affecting self-assessment (self-concept, self-efficacy, illusory superiority, gap filling); and ways to mitigate the inaccuracies of self-assessment (reflection, self-monitoring, external information seeking, and self-directed assessment seeking).For each theory, they suggest practical action steps for the learner, the teacher, and the learning environment in an effort to provide a road map for developing master learners.
An applied test of the social learning theory of deviance to college alcohol use.
DeMartino, Cynthia H; Rice, Ronald E; Saltz, Robert
2015-04-01
Several hypotheses about influences on college drinking derived from the social learning theory of deviance were tested and confirmed. The effect of ethnicity on alcohol use was completely mediated by differential association and differential reinforcement, whereas the effect of biological sex on alcohol use was partially mediated. Higher net positive reinforcements to costs for alcohol use predicted increased general use, more underage use, and more frequent binge drinking. Two unexpected finding were the negative relationship between negative expectations and negative experiences, and the substantive difference between nondrinkers and general drinkers compared with illegal or binge drinkers. The discussion considers implications for future campaigns based on Akers's deterrence theory.
Rafferty, Katherine A; Cramer, Emily; Priddis, DeAnne; Allen, Mike
2015-01-01
The theory of motivated information management (TMIM) provides one framework to examine information-seeking behaviors, especially in conversations involving sensitive or difficult information such as preferences for end-of-life (EOL) care. The spouse plays a significant role in decision making surrounding EOL care. Consequently, individuals need information about spouses' EOL preferences in order to ensure carrying out those desires. Our findings support the value of TMIM as a framework to understand factors that influence couples' EOL care information-seeking behaviors. In support of the theory, we provide factors that influence the initiation or avoidance of EOL conversations between spouses.
Attractors near grazing–sliding bifurcations
International Nuclear Information System (INIS)
Glendinning, P; Kowalczyk, P; Nordmark, A B
2012-01-01
In this paper we prove, for the first time, that multistability can occur in three-dimensional Fillipov type flows due to grazing–sliding bifurcations. We do this by reducing the study of the dynamics of Filippov type flows around a grazing–sliding bifurcation to the study of appropriately defined one-dimensional maps. In particular, we prove the presence of three qualitatively different types of multiple attractors born in grazing–sliding bifurcations. Namely, a period-two orbit with a sliding segment may coexist with a chaotic attractor, two stable, period-two and period-three orbits with a segment of sliding each may coexist, or a non-sliding and period-three orbit with two sliding segments may coexist
Erikson's Theory of Human Development as it Applies to the Aged: Wisdom as Contradictive Cognition
Clayton, Vivian
1975-01-01
Erikson's theory of human development is discussed; the question is raised as to whether most elderly individuals resolve the crisis between integrity and despair which signals the last stage of the life cycle. It is concluded that most individuals seek foreclosure or enter prolonged moratoriums after adolescence, never reaching this stage. (JMB)
Applying Grounded Theory to Weight Management among Women: Making a Commitment to Healthy Eating
Zunker, Christie; Ivankova, Nataliya
2011-01-01
In this study we developed a theory grounded in data from women who continued healthy eating behaviors after a weight management program. Participant recruitment was guided by theoretical sampling strategies for focus groups and individual interviews. Inclusion criteria were: African American or Caucasian women aged 30+ who lost [greater than or…
Min, Shangchao; He, Lianzhen
2014-01-01
This study examined the relative effectiveness of the multidimensional bi-factor model and multidimensional testlet response theory (TRT) model in accommodating local dependence in testlet-based reading assessment with both dichotomously and polytomously scored items. The data used were 14,089 test-takers' item-level responses to the testlet-based…
Normal Mode Theory Applied to Linear Arrays of Capacitive Micromachined Ultrasonic Transducers
Boulmé, Audren; Gross, Dominique; Heller, Jacques; Certon, Domnique
This paper describes the implementation of a new equivalent electroacoustic circuit for cMUT arrays. This circuit was obtained by using the normal mode theory. Theoretical simulations were also carried out from this new circuit to illustrate the impact of the trapped modes and some properties of the fundamental mode.
Applying Hand-Held 3D Printing Technology to the Teaching of VSEPR Theory
Dean, Natalie L.; Ewan, Corrina; McIndoe, J. Scott
2016-01-01
The use of hand-held 3D printing technology provides a unique and engaging approach to learning VSEPR theory by enabling students to draw three-dimensional depictions of different molecular geometries, giving them an appreciation of the shapes of the building blocks of complex molecular structures. Students are provided with 3D printing pens and…
Noel, Kristine K.; Westby, Carol
2014-01-01
This study employed a multiple baseline, across-participants, single-subject design to investigate the feasibility of an individual, narrative-based, social problem-solving intervention on the social problem-solving, narrative, and theory of mind (ToM) abilities of 3 incarcerated adolescent youth offenders identified as having emotional…
The Theory of Planned Behaviour Applied to Search Engines as a Learning Tool
Liaw, Shu-Sheng
2004-01-01
Search engines have been developed for helping learners to seek online information. Based on theory of planned behaviour approach, this research intends to investigate the behaviour of using search engines as a learning tool. After factor analysis, the results suggest that perceived satisfaction of search engine, search engines as an information…
Applying Developmental Theory and Research to the Creation of Educational Games
Revelle, Glenda
2013-01-01
The field of developmental psychology has produced abundant theory and research about the physical, cognitive, social, and emotional development of children; however, to date there has been limited use of this wealth of knowledge by developers creating games for children. This chapter provides an overview of key theoretical observations and…
The Keldysh formalism applied to time-dependent current-density-functional theory
Gidopoulos, NI; Wilson, S
2003-01-01
In this work we demonstrate how to derive the Kohn-Sham equations of time-dependent current-density functional theory from a generating action functional defined on a Keldysh time contour. These Kohn-Sham equations contain an exchange-correlation contribution to the vector potential. For this
When do mixotrophs specialize? Adaptive dynamics theory applied to a dynamic energy budget model.
Troost, T.A.; Kooi, B.W.; Kooijman, S.A.L.M.
2005-01-01
In evolutionary history, several events have occurred at which mixotrophs specialized into pure autotrophs and heterotrophs. We studied the conditions under which such events take place, using the Dynamic Energy Budget (DEB) theory for physiological rules of the organisms' metabolism and Adaptive
Applying Semiotic Theories to Graphic Design Education: An Empirical Study on Poster Design Teaching
Yang, Chao-Ming; Hsu, Tzu-Fan
2015-01-01
The rationales behind design are dissimilar to those behind art. Establishing an adequate theoretical foundation for conducting design education can facilitate scientising design methods. Thus, from the perspectives of the semiotic theories proposed by Saussure and Peirce, we investigated graphic design curricula by performing teaching…
Wimshurst, Kerry
2011-01-01
Criminal justice education is a relatively new program in higher education in many countries, and its curriculum and parameters remain unsettled. An exploratory study investigated whether threshold concepts theory provided a useful lens by which to explore student understandings of this multidisciplinary field. Eight high-performing final-year…
Mumford, Michael D.
1983-01-01
Reviewed characteristics of peer evaluations and notes their striking industrial validity. A review of the conditions under which peer evaluations yield strong validity coefficients as well as certain factor analytic and experimental studies indicated that social comparison theory might be useful for elucidating the nature of peer evaluation…
Hogg, Linda
2016-01-01
In New Zealand teacher practice is expected to be inclusive and supportive of all learners (Ministry of Education, 2007). However, diverse evidence highlights inequitable school experiences for Maori and Pasifika students. This study explored the application of funds of knowledge (FoK) theory within a New Zealand high school, with a focus on…
Catalano, Hannah Priest; Knowlden, Adam P.; Sharma, Manoj; Franzidis, Alexia
2016-01-01
Although college-aged women are at high risk for human papillomavirus (HPV) infection, many college women remain unvaccinated against HPV. Testing health behavior theory can assist sexuality educators in identifying behavioral antecedents to promote behavior change within an intervention. The purpose of this pilot study was to utilize social…
Hydraulic theory of sea straits applied to the onset of the Messinian Salinity Crisis
Meijer, P.Th.
2012-01-01
Theory for the dynamics of flow in sea straits holds promise to provide, in addition to geological evidence, insight into the configuration of the connection between the Mediterranean Sea and the Atlantic Ocean at the onset of the Messinian Salinity Crisis. This paper, for the first time,
Zhao, Huitao; Lu, Mengxia; Zuo, Junmei
2014-01-01
A controlled model for a financial system through washout-filter-aided dynamical feedback control laws is developed, the problem of anticontrol of Hopf bifurcation from the steady state is studied, and the existence, stability, and direction of bifurcated periodic solutions are discussed in detail. The obtained results show that the delay on price index has great influences on the financial system, which can be applied to suppress or avoid the chaos phenomenon appearing in the financial system.
Lu, Mengxia; Zuo, Junmei
2014-01-01
A controlled model for a financial system through washout-filter-aided dynamical feedback control laws is developed, the problem of anticontrol of Hopf bifurcation from the steady state is studied, and the existence, stability, and direction of bifurcated periodic solutions are discussed in detail. The obtained results show that the delay on price index has great influences on the financial system, which can be applied to suppress or avoid the chaos phenomenon appearing in the financial system. PMID:24977239
Dynamic stability and bifurcation analysis in fractional thermodynamics
Béda, Péter B.
2018-02-01
In mechanics, viscoelasticity was the first field of applications in studying geomaterials. Further possibilities arise in spatial non-locality. Non-local materials were already studied in the 1960s by several authors as a part of continuum mechanics and are still in focus of interest because of the rising importance of materials with internal micro- and nano-structure. When material instability gained more interest, non-local behavior appeared in a different aspect. The problem was concerned to numerical analysis, because then instability zones exhibited singular properties for local constitutive equations. In dynamic stability analysis, mathematical aspects of non-locality were studied by using the theory of dynamic systems. There the basic set of equations describing the behavior of continua was transformed to an abstract dynamic system consisting of differential operators acting on the perturbation field variables. Such functions should satisfy homogeneous boundary conditions and act as indicators of stability of a selected state of the body under consideration. Dynamic systems approach results in conditions for cases, when the differential operators have critical eigenvalues of zero real parts (dynamic stability or instability conditions). When the critical eigenvalues have non-trivial eigenspace, the way of loss of stability is classified as a typical (or generic) bifurcation. Our experiences show that material non-locality and the generic nature of bifurcation at instability are connected, and the basic functions of the non-trivial eigenspace can be used to determine internal length quantities of non-local mechanics. Fractional calculus is already successfully used in thermo-elasticity. In the paper, non-locality is introduced via fractional strain into the constitutive relations of various conventional types. Then, by defining dynamic systems, stability and bifurcation are studied for states of thermo-mechanical solids. Stability conditions and genericity
The so-called track theory of survival is wrong when applied to neutrons
International Nuclear Information System (INIS)
Guenther, K.
1976-01-01
Consideration is given to the errors associated with the application of the track-structure theory for the description of mammalian cell inactivation to the prediction of fast neutron r.b.e. values. The required radiosensitivity parameters are only known for some particular cell lines for which track segment survival data are available. The track-structure theory of cell inactivation is wrong for neutrons since the equation used by Katz and Sharma (Katz, R., and Sharma, S.C., 1973, Nucl. Instrum. Meth., vol. 111, 93) leads to an over-estimation of P in the range of small ion speed β, considering the relatively slow protons involved in a neutron-irradiated environment. In addition the charged recoils may not have enough range to traverse the sensitive volume completely as assumed by the theory (track-segment approximation). The apparently promising results of the theory for 14 MeV neutrons in the few cases where direct comparison with experimental data was possible must be considered as artefacts attributable to a fortuitous mutual compensation of errors at this energy. This balance breaks down at smaller neutron energies. The track-structure theory cannot therefore offer a tool for theoretical predictions of neutron r.b.e. values, and the numerous r.b.e.-dose curves calculated and compared with experimental data on animal tissues, organs and tumours (Katz, R., and Sharma, S.C., 1975, Phys. Med. Biol., vol. 20, 410) rather disprove than prove the suggested correspondence in r.b.e. of these clinical objects and end-points with cultured cells in vitro. (U.K.)
Bifurcation of Jovian magnetotail current sheet
Directory of Open Access Journals (Sweden)
P. L. Israelevich
2006-07-01
Full Text Available Multiple crossings of the magnetotail current sheet by a single spacecraft give the possibility to distinguish between two types of electric current density distribution: single-peaked (Harris type current layer and double-peaked (bifurcated current sheet. Magnetic field measurements in the Jovian magnetic tail by Voyager-2 reveal bifurcation of the tail current sheet. The electric current density possesses a minimum at the point of the Bx-component reversal and two maxima at the distance where the magnetic field strength reaches 50% of its value in the tail lobe.
Bifurcation of Jovian magnetotail current sheet
Directory of Open Access Journals (Sweden)
P. L. Israelevich
2006-07-01
Full Text Available Multiple crossings of the magnetotail current sheet by a single spacecraft give the possibility to distinguish between two types of electric current density distribution: single-peaked (Harris type current layer and double-peaked (bifurcated current sheet. Magnetic field measurements in the Jovian magnetic tail by Voyager-2 reveal bifurcation of the tail current sheet. The electric current density possesses a minimum at the point of the B_{x}-component reversal and two maxima at the distance where the magnetic field strength reaches 50% of its value in the tail lobe.
2010-01-01
Background Psychological models are used to understand and predict behaviour in a wide range of settings, but have not been consistently applied to health professional behaviours, and the contribution of differing theories is not clear. This study explored the usefulness of a range of models to predict an evidence-based behaviour -- the placing of fissure sealants. Methods Measures were collected by postal questionnaire from a random sample of general dental practitioners (GDPs) in Scotland. Outcomes were behavioural simulation (scenario decision-making), and behavioural intention. Predictor variables were from the Theory of Planned Behaviour (TPB), Social Cognitive Theory (SCT), Common Sense Self-regulation Model (CS-SRM), Operant Learning Theory (OLT), Implementation Intention (II), Stage Model, and knowledge (a non-theoretical construct). Multiple regression analysis was used to examine the predictive value of each theoretical model individually. Significant constructs from all theories were then entered into a 'cross theory' stepwise regression analysis to investigate their combined predictive value Results Behavioural simulation - theory level variance explained was: TPB 31%; SCT 29%; II 7%; OLT 30%. Neither CS-SRM nor stage explained significant variance. In the cross theory analysis, habit (OLT), timeline acute (CS-SRM), and outcome expectancy (SCT) entered the equation, together explaining 38% of the variance. Behavioural intention - theory level variance explained was: TPB 30%; SCT 24%; OLT 58%, CS-SRM 27%. GDPs in the action stage had significantly higher intention to place fissure sealants. In the cross theory analysis, habit (OLT) and attitude (TPB) entered the equation, together explaining 68% of the variance in intention. Summary The study provides evidence that psychological models can be useful in understanding and predicting clinical behaviour. Taking a theory-based approach enables the creation of a replicable methodology for identifying factors
Directory of Open Access Journals (Sweden)
Maclennan Graeme
2010-04-01
Full Text Available Abstract Background Psychological models are used to understand and predict behaviour in a wide range of settings, but have not been consistently applied to health professional behaviours, and the contribution of differing theories is not clear. This study explored the usefulness of a range of models to predict an evidence-based behaviour -- the placing of fissure sealants. Methods Measures were collected by postal questionnaire from a random sample of general dental practitioners (GDPs in Scotland. Outcomes were behavioural simulation (scenario decision-making, and behavioural intention. Predictor variables were from the Theory of Planned Behaviour (TPB, Social Cognitive Theory (SCT, Common Sense Self-regulation Model (CS-SRM, Operant Learning Theory (OLT, Implementation Intention (II, Stage Model, and knowledge (a non-theoretical construct. Multiple regression analysis was used to examine the predictive value of each theoretical model individually. Significant constructs from all theories were then entered into a 'cross theory' stepwise regression analysis to investigate their combined predictive value Results Behavioural simulation - theory level variance explained was: TPB 31%; SCT 29%; II 7%; OLT 30%. Neither CS-SRM nor stage explained significant variance. In the cross theory analysis, habit (OLT, timeline acute (CS-SRM, and outcome expectancy (SCT entered the equation, together explaining 38% of the variance. Behavioural intention - theory level variance explained was: TPB 30%; SCT 24%; OLT 58%, CS-SRM 27%. GDPs in the action stage had significantly higher intention to place fissure sealants. In the cross theory analysis, habit (OLT and attitude (TPB entered the equation, together explaining 68% of the variance in intention. Summary The study provides evidence that psychological models can be useful in understanding and predicting clinical behaviour. Taking a theory-based approach enables the creation of a replicable methodology for
Bonetti, Debbie; Johnston, Marie; Clarkson, Jan E; Grimshaw, Jeremy; Pitts, Nigel B; Eccles, Martin; Steen, Nick; Thomas, Ruth; Maclennan, Graeme; Glidewell, Liz; Walker, Anne
2010-04-08
Psychological models are used to understand and predict behaviour in a wide range of settings, but have not been consistently applied to health professional behaviours, and the contribution of differing theories is not clear. This study explored the usefulness of a range of models to predict an evidence-based behaviour -- the placing of fissure sealants. Measures were collected by postal questionnaire from a random sample of general dental practitioners (GDPs) in Scotland. Outcomes were behavioural simulation (scenario decision-making), and behavioural intention. Predictor variables were from the Theory of Planned Behaviour (TPB), Social Cognitive Theory (SCT), Common Sense Self-regulation Model (CS-SRM), Operant Learning Theory (OLT), Implementation Intention (II), Stage Model, and knowledge (a non-theoretical construct). Multiple regression analysis was used to examine the predictive value of each theoretical model individually. Significant constructs from all theories were then entered into a 'cross theory' stepwise regression analysis to investigate their combined predictive value. Behavioural simulation - theory level variance explained was: TPB 31%; SCT 29%; II 7%; OLT 30%. Neither CS-SRM nor stage explained significant variance. In the cross theory analysis, habit (OLT), timeline acute (CS-SRM), and outcome expectancy (SCT) entered the equation, together explaining 38% of the variance. Behavioural intention - theory level variance explained was: TPB 30%; SCT 24%; OLT 58%, CS-SRM 27%. GDPs in the action stage had significantly higher intention to place fissure sealants. In the cross theory analysis, habit (OLT) and attitude (TPB) entered the equation, together explaining 68% of the variance in intention. The study provides evidence that psychological models can be useful in understanding and predicting clinical behaviour. Taking a theory-based approach enables the creation of a replicable methodology for identifying factors that may predict clinical behaviour
Directory of Open Access Journals (Sweden)
Glidewell Elizabeth
2007-08-01
Full Text Available Abstract Background Psychological models can be used to understand and predict behaviour in a wide range of settings. However, they have not been consistently applied to health professional behaviours, and the contribution of differing theories is not clear. The aim of this study was to explore the usefulness of a range of psychological theories to predict health professional behaviour relating to management of upper respiratory tract infections (URTIs without antibiotics. Methods Psychological measures were collected by postal questionnaire survey from a random sample of general practitioners (GPs in Scotland. The outcome measures were clinical behaviour (using antibiotic prescription rates as a proxy indicator, behavioural simulation (scenario-based decisions to managing URTI with or without antibiotics and behavioural intention (general intention to managing URTI without antibiotics. Explanatory variables were the constructs within the following theories: Theory of Planned Behaviour (TPB, Social Cognitive Theory (SCT, Common Sense Self-Regulation Model (CS-SRM, Operant Learning Theory (OLT, Implementation Intention (II, Stage Model (SM, and knowledge (a non-theoretical construct. For each outcome measure, multiple regression analysis was used to examine the predictive value of each theoretical model individually. Following this 'theory level' analysis, a 'cross theory' analysis was conducted to investigate the combined predictive value of all significant individual constructs across theories. Results All theories were tested, but only significant results are presented. When predicting behaviour, at the theory level, OLT explained 6% of the variance and, in a cross theory analysis, OLT 'evidence of habitual behaviour' also explained 6%. When predicting behavioural simulation, at the theory level, the proportion of variance explained was: TPB, 31%; SCT, 26%; II, 6%; OLT, 24%. GPs who reported having already decided to change their management to
Eccles, Martin P; Grimshaw, Jeremy M; Johnston, Marie; Steen, Nick; Pitts, Nigel B; Thomas, Ruth; Glidewell, Elizabeth; Maclennan, Graeme; Bonetti, Debbie; Walker, Anne
2007-08-03
Psychological models can be used to understand and predict behaviour in a wide range of settings. However, they have not been consistently applied to health professional behaviours, and the contribution of differing theories is not clear. The aim of this study was to explore the usefulness of a range of psychological theories to predict health professional behaviour relating to management of upper respiratory tract infections (URTIs) without antibiotics. Psychological measures were collected by postal questionnaire survey from a random sample of general practitioners (GPs) in Scotland. The outcome measures were clinical behaviour (using antibiotic prescription rates as a proxy indicator), behavioural simulation (scenario-based decisions to managing URTI with or without antibiotics) and behavioural intention (general intention to managing URTI without antibiotics). Explanatory variables were the constructs within the following theories: Theory of Planned Behaviour (TPB), Social Cognitive Theory (SCT), Common Sense Self-Regulation Model (CS-SRM), Operant Learning Theory (OLT), Implementation Intention (II), Stage Model (SM), and knowledge (a non-theoretical construct). For each outcome measure, multiple regression analysis was used to examine the predictive value of each theoretical model individually. Following this 'theory level' analysis, a 'cross theory' analysis was conducted to investigate the combined predictive value of all significant individual constructs across theories. All theories were tested, but only significant results are presented. When predicting behaviour, at the theory level, OLT explained 6% of the variance and, in a cross theory analysis, OLT 'evidence of habitual behaviour' also explained 6%. When predicting behavioural simulation, at the theory level, the proportion of variance explained was: TPB, 31%; SCT, 26%; II, 6%; OLT, 24%. GPs who reported having already decided to change their management to try to avoid the use of antibiotics made
Finite-time nonautonomous bifurcation in impulsive systems
Directory of Open Access Journals (Sweden)
Marat Akhmet
2016-08-01
Full Text Available The purpose of this article is to investigate nonautonomous bifurcation in impulsive differential equations. The impulsive finite-time analogues of transcritical and pitchfork bifurcation are provided.
Bifurcation structure of a model of bursting pancreatic cells
DEFF Research Database (Denmark)
Mosekilde, Erik; Lading, B.; Yanchuk, S.
2001-01-01
One- and two-dimensional bifurcation studies of a prototypic model of bursting oscillations in pancreatic P-cells reveal a squid-formed area of chaotic dynamics in the parameter plane, with period-doubling bifurcations on one side of the arms and saddle-node bifurcations on the other. The transit......One- and two-dimensional bifurcation studies of a prototypic model of bursting oscillations in pancreatic P-cells reveal a squid-formed area of chaotic dynamics in the parameter plane, with period-doubling bifurcations on one side of the arms and saddle-node bifurcations on the other....... The transition from this structure to the so-called period-adding structure is found to involve a subcritical period-doubling bifurcation and the emergence of type-III intermittency. The period-adding transition itself is not smooth but consists of a saddle-node bifurcation in which (n + 1)-spike bursting...
Bifurcations of a class of singular biological economic models
International Nuclear Information System (INIS)
Zhang Xue; Zhang Qingling; Zhang Yue
2009-01-01
This paper studies systematically a prey-predator singular biological economic model with time delay. It shows that this model exhibits two bifurcation phenomena when the economic profit is zero. One is transcritical bifurcation which changes the stability of the system, and the other is singular induced bifurcation which indicates that zero economic profit brings impulse, i.e., rapid expansion of the population in biological explanation. On the other hand, if the economic profit is positive, at a critical value of bifurcation parameter, the system undergoes a Hopf bifurcation, i.e., the increase of delay destabilizes the system and bifurcates into small amplitude periodic solution. Finally, by using Matlab software, numerical simulations illustrate the effectiveness of the results obtained here. In addition, we study numerically that the system undergoes a saddle-node bifurcation when the bifurcation parameter goes through critical value of positive economic profit.
Directory of Open Access Journals (Sweden)
Andrés Pavas
2011-06-01
Full Text Available Currently the impact of high efficient lighting devices such as compact fluorescent lamps (CFL and light emitting diodes (LED is an important concern for the electrotechnical community. This paper makes a contribution towards determining the impact of these devices on electric grid power quality and efficiency, proposed by means of applying FBD-power theory to the currents absorbed by CFLs and LEDs. An analysis of the waveform distortion regarding IEEE standard 519 and efficiency detriment quantification are presented.
Hribar-Lee, Barbara; Lukšič, Miha
2018-01-24
By means of replica Ornstein-Zernike theory (supplemented in a few cases by Monte Carlo simulations) we examined the distribution of an annealed primitive model +1:-1 electrolyte in a mixture with uncharged hard spheres, or another model +1:-1 or +2:-1 electrolyte inside and outside the quenched vesicles, decorated by a model membrane, and across the membrane phase. We explored the influence of the size and charge of the annealed fluid on the partition equilibrium, as well as the effect of the vesicle size and membrane interaction parameters (repulsive barrier height, attractive depth, and membrane width). A hydrophobic cation, present in the mixture with NaCl, slightly enhanced the concentration of sodium ions inside the model vesicle, compared to pure NaCl solution. The replica theory was in good agreement with computer simulations and as such adequate for studying partitioning of small and hydrophobic ions or hydrophobic solutes across model membranes.
Applying cognitive acuity theory to the development and scoring of situational judgment tests.
Leeds, J Peter
2017-11-09
The theory of cognitive acuity (TCA) treats the response options within items as signals to be detected and uses psychophysical methods to estimate the respondents' sensitivity to these signals. Such a framework offers new methods to construct and score situational judgment tests (SJT). Leeds (2012) defined cognitive acuity as the capacity to discern correctness and distinguish between correctness differences among simultaneously presented situation-specific response options. In this study, SJT response options were paired in order to offer the respondent a two-option choice. The contrast in correctness valence between the two options determined the magnitude of signal emission, with larger signals portending a higher probability of detection. A logarithmic relation was found between correctness valence contrast (signal stimulus) and its detectability (sensation response). Respondent sensitivity to such signals was measured and found to be related to the criterion variables. The linkage between psychophysics and elemental psychometrics may offer new directions for measurement theory.
Secondary bifurcation for a nonlocal Allen-Cahn equation
Kuto, Kousuke; Mori, Tatsuki; Tsujikawa, Tohru; Yotsutani, Shoji
2017-09-01
This paper studies the Neumann problem of a nonlocal Allen-Cahn equation in an interval. A main result finds a symmetry breaking (secondary) bifurcation point on the bifurcation curve of solutions with odd-symmetry. Our proof is based on a level set analysis for the associated integral map. A method using the complete elliptic integrals proves the uniqueness of secondary bifurcation point. We also show some numerical simulations concerning the global bifurcation structure.
Applying developmental theory and research to the creation of educational games.
Revelle, Glenda
2013-01-01
The field of developmental psychology has produced abundant theory and research about the physical, cognitive, social, and emotional development of children; however, to date there has been limited use of this wealth of knowledge by developers creating games for children. This chapter provides an overview of key theoretical observations and research-based insight regarding children's development and outlines practical implications for their application to game design. Copyright © 2013 Wiley Periodicals, Inc., A Wiley Company.
The Determinants of Medical Tourism Intentions: Applying the Theory of Planned Behavior.
Ramamonjiarivelo, Zo; Martin, David S; Martin, Warren S
2015-01-01
This study introduces the theory of planned behavior to health care marketers by extending and replicating a prior study that predicted student's intention to engage in medical tourism. Based on a sample of 164 usable survey responses, our findings suggested that the MEDTOUR scale (developed and introduced a prior study) is robust and works reasonably well with a national sample. Based on these findings, MEDTOUR appears to be worthy of further consideration by health marketing scholars.
Just War Theory Applied to US Policy in Pakistan and Yemen
2014-05-12
provides legitimacy, but it is not the only means of earning it. When facing such a dilemma, nothing is more appropriate than Just War Theory. Just...attempt to protect society as a whole from the hazards of war. In an insurgency, earning the trust of the populace and reinforcing the legitimacy of the...for this failing is that the war is not between two states, but one state and an organization dedicated to expelling infidels .132 Coming to a peace
On the validity of the classical hydrodynamic lubrication theory applied to squeeze film dampers
International Nuclear Information System (INIS)
Danaila, S; Moraru, L
2010-01-01
Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ball-bearings-SFD-squirrel-cage assembly at one end and by rigidly mounted ball bearings at the other end are computed using the bearing forces provided by the classical short bearing theory. The numerical model also includes the properties of the squirrel cage. The parameters of the squirrel cage were measured, together with the effect of the friction within the assembly. Experimental unbalance responses were also collected for various rotation speeds and unbalances to validate the numerical simulations.
On the validity of the classical hydrodynamic lubrication theory applied to squeeze film dampers
Energy Technology Data Exchange (ETDEWEB)
Danaila, S; Moraru, L, E-mail: sterian.danaila@gmail.co [' Elie Carafoli' Department of Aerospace Sciences, Faculty of Aerospace Engineering, ' Politehnica' University of Bucharest, Spl. Independentei 313, Bucharest (Romania)
2010-08-15
Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ball-bearings-SFD-squirrel-cage assembly at one end and by rigidly mounted ball bearings at the other end are computed using the bearing forces provided by the classical short bearing theory. The numerical model also includes the properties of the squirrel cage. The parameters of the squirrel cage were measured, together with the effect of the friction within the assembly. Experimental unbalance responses were also collected for various rotation speeds and unbalances to validate the numerical simulations.
On the validity of the classical hydrodynamic lubrication theory applied to squeeze film dampers
Dănăilă, S.; Moraru, L.
2010-08-01
Squeeze film dampers (SFD) are devices utilized to control vibrations of the shafts of high-speed rotating machinery. The SFD - squirrel cage combination is probably the most used system for tuning the stiffness and damping of the supports for rotors installed on ball bearings. Squeeze film dampers are essentially hydrodynamic bearings which contain the ball bearings housings of ball-bearings supported shafts. Consequently, the oil film within the SFD are influenced only by the precession and nutation of the shaft, that is the flow of the oil within the damper is not directly influenced by the spin of the rotor. However, in the classical theory, the flow in the thin film is also governed by the Reynolds equation. In this paper, some of the limits of the classical theory of the SFD are discussed and theoretical and experimental studies, which illustrate the ideas presented herein, are presented as well. The orbits of an unbalanced rotor that is supported by a ball-bearings-SFD-squirrel-cage assembly at one end and by rigidly mounted ball bearings at the other end are computed using the bearing forces provided by the classical short bearing theory. The numerical model also includes the properties of the squirrel cage. The parameters of the squirrel cage were measured, together with the effect of the friction within the assembly. Experimental unbalance responses were also collected for various rotation speeds and unbalances to validate the numerical simulations.
Directory of Open Access Journals (Sweden)
Octav-Ionuţ Macovei
2015-08-01
Full Text Available This paper aims to propose and validate a model based on the Theory of Planned Behavior in order to explain consumers’ pro-environmental behaviour regarding energy conservation. The model was constructed using the five variables from Ajzen’s Theory of Planned Behavior (TPB (behaviour, intention, perceived behavioural control, subjective norms and attitude to which a variable adapted from Schwartz’s Norm Activation Theory (NAT was added (“awareness of the consequences and the need” in order to create a unique model adapted for the special case of energy conservation behaviour. Further, a survey was conducted and the data collected were analysed using structural equation modelling. The first step of data analysis confirmed that all the constructs have good reliability, internal consistency and validity. The results of the structural equation analysis validated the proposed model, with all the model fit and quality indices having very good values. In the analysis of consumers’ proenvironmental behaviour regarding energy conservation and their intention to behave in a proenvironmental manner, this model proved to have a strong predictive power. Five of seven hypotheses were validated, the newly introduced variable proving to be a success. The proposed model is unique and will offer companies and organizations a valuable green marketing tool which can be used in the fight for environment protection and energy conservation.
Shipley, Andrew
2008-04-01
Social Identity Theory and the concept of social comparison have inspired research on individuals, addressing effects of personal and environmental factors in directing social attention. The theory's conceptual origins, however, suggest that social comparison may have behavioral implications as well. Such behaviors may include attempts by an individual to enhance the relative status of his ingroup on a salient dimension of comparison. Such behavior is referred to as "social competition." In two studies, the effects of social comparison and social competition were measured in the real-world environment of community food drives. Participants were aggregated by household; 600 households in upper middle-class neighborhoods in Eugene and Salem, Oregon, were contacted. In Study 1 of 300 households, it was hypothesized that inclusion of a social competition cue in requests for donation would significantly increase the likelihood of donation. This hypothesis was supported. Study 2 was done to clarify the possible role in a social comparison of perceived ingroup inferiority in the prior observed increase in donations. The inclusion of a social comparison cue in the donation request significantly increased donations in households of the second study. The findings suggest that researchers should expand study of the theory's behavioral implications, including the role of social comparison in prosocial behavior.
Bonetti, Debbie; Pitts, Nigel B; Eccles, Martin; Grimshaw, Jeremy; Johnston, Marie; Steen, Nick; Glidewell, Liz; Thomas, Ruth; Maclennan, Graeme; Clarkson, Jan E; Walker, Anne
2006-10-01
This study applies psychological theory to the implementation of evidence-based clinical practice. The first objective was to see if variables from psychological frameworks (developed to understand, predict and influence behaviour) could predict an evidence-based clinical behaviour. The second objective was to develop a scientific rationale to design or choose an implementation intervention. Variables from the Theory of Planned Behaviour, Social Cognitive Theory, Self-Regulation Model, Operant Conditioning, Implementation Intentions and the Precaution Adoption Process were measured, with data collection by postal survey. The primary outcome was the number of intra-oral radiographs taken per course of treatment collected from a central fee claims database. Participants were 214 Scottish General Dental Practitioners. At the theory level, the Theory of Planned Behaviour explained 13% variance in the number of radiographs taken, Social Cognitive Theory explained 7%, Operant Conditioning explained 8%, Implementation Intentions explained 11%. Self-Regulation and Stage Theory did not predict significant variance in radiographs taken. Perceived behavioural control, action planning and risk perception explained 16% of the variance in number of radiographs taken. Knowledge did not predict the number of radiographs taken. The results suggest an intervention targeting predictive psychological variables could increase the implementation of this evidence-based practice, while influencing knowledge is unlikely to do so. Measures which predicted number of radiographs taken also predicted intention to take radiographs, and intention accounted for significant variance in behaviour (adjusted R(2)=5%: F(1,166)=10.28, ptheory-based approach enabled the creation of a methodology that can be replicated for identifying factors predictive of clinical behaviour and for the design and choice of interventions to modify practice as new evidence emerges.
Bifurcating Solutions to the Monodomain Model Equipped with FitzHugh-Nagumo Kinetics
Directory of Open Access Journals (Sweden)
Robert Artebrant
2009-01-01
cells surrounded by collections of normal cells. Thus, the cell model features a discontinuous coefficient. Analytical techniques are applied to approximate the time-periodic solution that arises at the Hopf bifurcation point. Accurate numerical experiments are employed to complement our findings.
Stability and Bifurcation in Magnetic Flux Feedback Maglev Control System
Directory of Open Access Journals (Sweden)
Wen-Qing Zhang
2013-01-01
Full Text Available Nonlinear properties of magnetic flux feedback control system have been investigated mainly in this paper. We analyzed the influence of magnetic flux feedback control system on control property by time delay and interfering signal of acceleration. First of all, we have established maglev nonlinear model based on magnetic flux feedback and then discussed hopf bifurcation’s condition caused by the acceleration’s time delay. The critical value of delayed time is obtained. It is proved that the period solution exists in maglev control system and the stable condition has been got. We obtained the characteristic values by employing center manifold reduction theory and normal form method, which represent separately the direction of hopf bifurcation, the stability of the period solution, and the period of the period motion. Subsequently, we discussed the influence maglev system on stability of by acceleration’s interfering signal and obtained the stable domain of interfering signal. Some experiments have been done on CMS04 maglev vehicle of National University of Defense Technology (NUDT in Tangshan city. The results of experiments demonstrate that viewpoints of this paper are correct and scientific. When time lag reaches the critical value, maglev system will produce a supercritical hopf bifurcation which may cause unstable period motion.
Smooth bifurcation for an obstacle problem
Czech Academy of Sciences Publication Activity Database
Eisner, Jan; Kučera, Milan; Recke, L.
2005-01-01
Roč. 18, č. 2 (2005), s. 121-140 ISSN 0893-4983 R&D Projects: GA AV ČR(CZ) IAA1019202 Institutional research plan: CEZ:AV0Z10190503 Keywords : bifurcation * unilaterally supported beam * variational inequalities Subject RIV: BA - General Mathematics
Digital subtraction angiography of carotid bifurcation
International Nuclear Information System (INIS)
Vries, A.R. de.
1984-01-01
This study demonstrates the reliability of digital subtraction angiography (DSA) by means of intra- and interobserver investigations as well as indicating the possibility of substituting catheterangiography by DSA in the diagnosis of carotid bifurcation. Whenever insufficient information is obtained from the combination of non-invasive investigation and DSA, a catheterangiogram will be necessary. (Auth.)
Bifurcation of self-folded polygonal bilayers
Abdullah, Arif M.; Braun, Paul V.; Hsia, K. Jimmy
2017-09-01
Motivated by the self-assembly of natural systems, researchers have investigated the stimulus-responsive curving of thin-shell structures, which is also known as self-folding. Self-folding strategies not only offer possibilities to realize complicated shapes but also promise actuation at small length scales. Biaxial mismatch strain driven self-folding bilayers demonstrate bifurcation of equilibrium shapes (from quasi-axisymmetric doubly curved to approximately singly curved) during their stimulus-responsive morphing behavior. Being a structurally instable, bifurcation could be used to tune the self-folding behavior, and hence, a detailed understanding of this phenomenon is appealing from both fundamental and practical perspectives. In this work, we investigated the bifurcation behavior of self-folding bilayer polygons. For the mechanistic understanding, we developed finite element models of planar bilayers (consisting of a stimulus-responsive and a passive layer of material) that transform into 3D curved configurations. Our experiments with cross-linked Polydimethylsiloxane samples that change shapes in organic solvents confirmed our model predictions. Finally, we explored a design scheme to generate gripper-like architectures by avoiding the bifurcation of stimulus-responsive bilayers. Our research contributes to the broad field of self-assembly as the findings could motivate functional devices across multiple disciplines such as robotics, artificial muscles, therapeutic cargos, and reconfigurable biomedical devices.
Equilibrium-torus bifurcation in nonsmooth systems
DEFF Research Database (Denmark)
Zhusubahyev, Z.T.; Mosekilde, Erik
2008-01-01
Considering a set of two coupled nonautonomous differential equations with discontinuous right-hand sides describing the behavior of a DC/DC power converter, we discuss a border-collision bifurcation that can lead to the birth of a two-dimensional invariant torus from a stable node equilibrium...
Bifurcation of elastic solids with sliding interfaces
Bigoni, D.; Bordignon, N.; Piccolroaz, A.; Stupkiewicz, S.
2018-01-01
Lubricated sliding contact between soft solids is an interesting topic in biomechanics and for the design of small-scale engineering devices. As a model of this mechanical set-up, two elastic nonlinear solids are considered jointed through a frictionless and bilateral surface, so that continuity of the normal component of the Cauchy traction holds across the surface, but the tangential component is null. Moreover, the displacement can develop only in a way that the bodies in contact do neither detach, nor overlap. Surprisingly, this finite strain problem has not been correctly formulated until now, so this formulation is the objective of the present paper. The incremental equations are shown to be non-trivial and different from previously (and erroneously) employed conditions. In particular, an exclusion condition for bifurcation is derived to show that previous formulations based on frictionless contact or `spring-type' interfacial conditions are not able to predict bifurcations in tension, while experiments-one of which, ad hoc designed, is reported-show that these bifurcations are a reality and become possible when the correct sliding interface model is used. The presented results introduce a methodology for the determination of bifurcations and instabilities occurring during lubricated sliding between soft bodies in contact.
Percutaneous coronary intervention for coronary bifurcation disease
DEFF Research Database (Denmark)
Lassen, Jens Flensted; Holm, Niels Ramsing; Banning, Adrian
2016-01-01
of combining the opinions of interventional cardiologists with the opinions of a large variety of other scientists on bifurcation management. The present 11th EBC consensus document represents the summary of the up-to-date EBC consensus and recommendations. It points to the fact that there is a multitude...
Technology limitations of BRS in bifurcations.
Fox, Julia; Hossainy, Syed; Rapoza, Richard; Serruys, Patrick W
2015-01-01
Recommended techniques for bifurcation stenting continue to be revised with specific attention to bioresorbable scaffolds (BRS). Optimal procedural success and long-term outcomes with BRS can perhaps be improved with careful attention to implantation techniques. Good vessel preparation is imperative for optimal expansion of the scaffold, and proper vessel sizing is necessary to ensure compliance with scaffold expansion limits and preservation of proper scaffold function. The European Bifurcation Club (EBC) recommends provisional stenting for the majority of bifurcation lesions: permanent metallic stents are sized according to the distal vessel diameter, with subsequent post-dilatation of the proximal vessel to ensure stent apposition in the proximal main vessel. Recent BRS-specific modifications to the EBC recommendation suggest that selecting the scaffold size based on the diameter of the proximal main vessel can mitigate the risk of overexpansion and potential strut fracture. Expansion of the BRS requires a thoughtful balance between the risk of malapposition associated with underdeployment and the risk of strut fracture due to overdeployment. Post-dilatation of scaffolds should be performed, always respecting the maximum expansion limit, to correct any potential scaffold malapposition and minimise flow disturbances. Finally, dual antiplatelet therapy plays an important role in BRS bifurcation treatment to avoid thromboembolic events.
Hematocrit dispersion in asymmetrically bifurcating vascular networks
Sriram, Krishna; Intaglietta, Marcos
2014-01-01
Quantitative modeling of physiological processes in vasculatures requires an accurate representation of network topology, including vessel branching. We propose a new approach for reconstruction of vascular network, which determines how vessel bifurcations distribute red blood cells (RBC) in the microcirculation. Our method follows the foundational premise of Murray's law in postulating the existence of functional optimality of such networks. It accounts for the non-Newtonian behavior of blood by allowing the apparent blood viscosity to vary with discharge hematocrit and vessel radius. The optimality criterion adopted in our approach is the physiological cost of supplying oxygen to the tissue surrounding a blood vessel. Bifurcation asymmetry is expressed in terms of the amount of oxygen consumption associated with the respective tissue volumes being supplied by each daughter vessel. The vascular networks constructed with our approach capture a number of physiological characteristics observed in in vivo studies. These include the nonuniformity of wall shear stress in the microcirculation, the significant increase in pressure gradients in the terminal sections of the network, the nonuniformity of both the hematocrit partitioning at vessel bifurcations and hematocrit across the capillary bed, and the linear relationship between the RBC flux fraction and the blood flow fraction at bifurcations. PMID:25217657
Fouquier, Katherine Ferrell
2013-01-01
This article reviews the current state of knowledge of the theory of maternal role attainment (MRA) and its relevance in describing African American motherhood. EBSCOhost Research Databases that included PubMed, CINAHL plus, MEDLINE, PsycINFO, SCOPUS, and Web of Science were searched for journal articles that examined maternal identity and MRA. Keyword searches included maternal identity, maternal role attainment, becoming a mother, prenatal attachment, maternal-fetal attachment, and maternal-infant attachment. Inclusion criteria for this review were published journal articles of studies conducted in the United States, with a clear delineation of the theoretical framework of MRA. Journal articles that measured MRA among women with depression or medically fragile infants were excluded. Two hundred and twelve studies were reviewed; 25 studies, published between 1975 and 2007, met the inclusion criteria. Nine articles described the theory of MRA, 11 articles measured variables thought to influence MRA, and 6 articles described maternal-fetal attachment, a construct of MRA. Studies were reviewed, categorized, and analyzed to determine current knowledge of how the theory of MRA describes African American motherhood. Categories included studies describing the theoretical framework of maternal identity and MRA, studies measuring key variables thought to impact MRA, and studies measuring maternal-fetal attachment and maternal-infant attachment. The studies were limited by homogenous samples of upper-middle-class white women and low-income, single, African American adolescents. Study results of MRA cannot be generalized to African American women. Further research is essential to identify attributes influencing MRA, specifically among larger samples of African American women with demographics similar to that of the white populations that have been included in studies thus far. © 2013 by the American College of Nurse-Midwives.
International Nuclear Information System (INIS)
Rossini, M.R.
1992-01-01
An attempt has been made to obtain a strategy coherent with the available instruments and that could be implemented with future developments. A calculation methodology was developed for fuel reload in PWR reactors, which evolves cell calculation with the HAMMER-TECHNION code and neutronics calculation with the CITATION code.The management strategy adopted consists of fuel element position changing at the beginning of each reactor cycle in order to decrease the radial peak factor. The bi-dimensional, two group First Order perturbation theory was used for the mathematical modeling. (L.C.J.A.)
DEFF Research Database (Denmark)
Tell, Paolo; Ali Babar, Muhammad
2012-01-01
Although a plethora of tools are available for Global Software Engineering (GSE) teams, it is being realized increasingly that the most prevalent desktop metaphor underpinning the majority of tools have several inherent limitations. We have proposed that Activity-Based Computing (ABC) can...... be a promising alternative to build tools for GSE. However, significant effort is required to introduce a new paradigm; there is a need of sound theoretical foundation based on activity theory to address challenges faced by tools in GSE. This paper reports our effort aimed at building theoretical foundations...
The Quantum Mechanics Solver: How to Apply Quantum Theory to Modern Physics, 2nd edition
International Nuclear Information System (INIS)
Robbin, J M
2007-01-01
he hallmark of a good book of problems is that it allows you to become acquainted with an unfamiliar topic quickly and efficiently. The Quantum Mechanics Solver fits this description admirably. The book contains 27 problems based mainly on recent experimental developments, including neutrino oscillations, tests of Bell's inequality, Bose-Einstein condensates, and laser cooling and trapping of atoms, to name a few. Unlike many collections, in which problems are designed around a particular mathematical method, here each problem is devoted to a small group of phenomena or experiments. Most problems contain experimental data from the literature, and readers are asked to estimate parameters from the data, or compare theory to experiment, or both. Standard techniques (e.g., degenerate perturbation theory, addition of angular momentum, asymptotics of special functions) are introduced only as they are needed. The style is closer to a non-specialist seminar rather than an undergraduate lecture. The physical models are kept simple; the emphasis is on cultivating conceptual and qualitative understanding (although in many of the problems, the simple models fit the data quite well). Some less familiar theoretical techniques are introduced, e.g. a variational method for lower (not upper) bounds on ground-state energies for many-body systems with two-body interactions, which is then used to derive a surprisingly accurate relation between baryon and meson masses. The exposition is succinct but clear; the solutions can be read as worked examples if you don't want to do the problems yourself. Many problems have additional discussion on limitations and extensions of the theory, or further applications outside physics (e.g., the accuracy of GPS positioning in connection with atomic clocks; proton and ion tumor therapies in connection with the Bethe-Bloch formula for charged particles in solids). The problems use mainly non-relativistic quantum mechanics and are organised into three
Applying the Theory of Constraints in the Course of Process Improvement
Marton, Michal; Paulová, Iveta
2010-01-01
Theory of constraints (TOC) is about thinking in logical, systematic, or structured processes similar to the PDCA learning loop. It is about analyzing cause and effect, verifying basic assumptions, exploring alternatives and process improvement. The goal of TOC is to maximize the efficiency of a process selectively at the most critical points and thereby maximize profitability, quality, or other corporate objectives. This paper include basic theoretical information about TOC and following application during process improvement. This paper was realised with VEGA support No. 1/0229/08 Perspectives of quality management development in coherence with requirements of Slovak republic market.
Applying the Theory of Reasoned Action to Entrepreneurship within a University Setting
Directory of Open Access Journals (Sweden)
Inés Rueda Sampedro
2013-01-01
Full Text Available This paper analyses the effect of the perceived advantages and disadvantages of entrepreneurship surrounding the starting of a new business and it is based on the Theory of Reasoned Action. The sample contains 274 students of the Faculty of Business and Economics (University of Cantabria. A structural equation approach is used to test the research hypotheses. The results obtained show that the entrepreneurship advantages influence a college student’s attitude and later have an impact on their entrepreneurial intentions. However, the disadvantages associated with entrepreneurship have no significant effect.
Applying Customer Satisfaction Theory to Community College Planning of Counseling Services.
Hom, Willard C.
2002-01-01
This article discusses a framework in which a researcher may apply a customer satisfaction model to the planning of counseling services at the community college level. It also reviews some historical work on satisfaction research with the unique environment of student services in two-year colleges. The article suggests that readers could benefit…
How can a Theory of Change framework be applied to short-term international volunteering?
Loiseau, Bethina; Benedict, Darren; Sibbald, Rebekah; Raman, Salem A; Loh, Lawrence C; Dimaras, Helen
2016-09-01
Short-term international volunteering has become enormously popular among individuals from high-income countries who travel to low-income countries to offer support on initiatives often related to health and development. However, their impact on global development is questionable, particularly when volunteer skills are not matched to local needs, or when teams operate outside the local health system. Furthermore, the impact of these volunteer programs is rarely evaluated. Theory of Change is a framework for program design meant to facilitate measurable social change. We propose that a Theory of Change framework, appropriately deployed in the design and conduct of short-term international volunteerism, could help improve volunteer efforts by identifying problems and clearly defining goals, designing and implementing effective strategies, and evaluating the real impacts these have on identified concerns. © The Author 2016. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Applying Critical Race Theory to Group Model Building Methods to Address Community Violence.
Frerichs, Leah; Lich, Kristen Hassmiller; Funchess, Melanie; Burrell, Marcus; Cerulli, Catherine; Bedell, Precious; White, Ann Marie
2016-01-01
Group model building (GMB) is an approach to building qualitative and quantitative models with stakeholders to learn about the interrelationships among multilevel factors causing complex public health problems over time. Scant literature exists on adapting this method to address public health issues that involve racial dynamics. This study's objectives are to (1) introduce GMB methods, (2) present a framework for adapting GMB to enhance cultural responsiveness, and (3) describe outcomes of adapting GMB to incorporate differences in racial socialization during a community project seeking to understand key determinants of community violence transmission. An academic-community partnership planned a 1-day session with diverse stakeholders to explore the issue of violence using GMB. We documented key questions inspired by critical race theory (CRT) and adaptations to established GMB "scripts" (i.e., published facilitation instructions). The theory's emphasis on experiential knowledge led to a narrative-based facilitation guide from which participants created causal loop diagrams. These early diagrams depict how violence is transmitted and how communities respond, based on participants' lived experiences and mental models of causation that grew to include factors associated with race. Participants found these methods useful for advancing difficult discussion. The resulting diagrams can be tested and expanded in future research, and will form the foundation for collaborative identification of solutions to build community resilience. GMB is a promising strategy that community partnerships should consider when addressing complex health issues; our experience adapting methods based on CRT is promising in its acceptability and early system insights.
Dippel, Elizabeth A; Hanson, Jessica D; McMahon, Tracey R; Griese, Emily R; Kenyon, DenYelle B
2017-07-01
Objectives American Indian girls have higher teen pregnancy rates than the national rate. Intervention studies that utilize the Theory of Reasoned Action have found that changing attitudes and subjective norms often leads to subsequent change in a variety of health behaviors in young adults. The current study goal is to better understand sexual decision-making among American Indian youth using the Theory of Reasoned Action model and to introduce ways to utilize attitudes and subjective norms to modify risky behaviors. Methods The project collected qualitative data at a reservation site and an urban site through 16 focus groups with American Indian young people aged 16-24. Results Attitudes towards, perceived impact of, and perception of how others felt about teen pregnancy vary between American Indian parents and non-parents. Particularly, young American Indian parents felt more negatively about teen pregnancy. Participants also perceived a larger impact on female than male teen parents. Conclusions There are differences between American Indian parents and non-parents regarding attitudes towards, the perceived impact of, and how they perceived others felt about teen pregnancy. Teen pregnancy prevention programs for American Indian youth should include youth parents in curriculum creation and curriculum that addresses normative beliefs about teen pregnancy and provides education on the ramifications of teen pregnancy to change attitudes.
Applying an extended theory of planned behaviour to predict breakfast consumption in adolescents.
Kennedy, S; Davies, E L; Ryan, L; Clegg, M E
2017-05-01
Breakfast skipping increases during adolescence and is associated with lower levels of physical activity and weight gain. Theory-based interventions promoting breakfast consumption in adolescents report mixed findings, potentially because of limited research identifying which determinants to target. This study aimed to: (i) utilise the Theory of Planned Behaviour (TPB) to identify the relative contribution of attitudes (affective, cognitive and behavioural) to predict intention to eat breakfast and breakfast consumption in adolescents and (ii) determine whether demographic factors moderate the relationship between TPB variables, intention and behaviour. Questionnaires were completed by 434 students (mean 14±0.9 years) measuring breakfast consumption (0-2, 3-6 or 7 days), physical activity levels and TPB measures. Data were analysed by breakfast frequency and demographics using hierarchical and multinomial regression analyses. Breakfast was consumed everyday by 57% of students, with boys more likely to eat a regular breakfast, report higher activity levels and report more positive attitudes towards breakfast than girls (Pbreakfast behaviours (Pbreakfast frequency. Interactions between gender and intentions were significant when comparing 0-2- and 3-6-day breakfast eaters only highlighting a stronger intention-behaviour relationship for girls. Findings confirm that the TPB is a successful model for predicting breakfast intentions and behaviours in adolescents. The potential for a direct effect of attitudes on behaviours should be considered in the implementation and design of breakfast interventions.
Applying cognitive learning theories to understanding of learning in vulnerable groups of adults
Directory of Open Access Journals (Sweden)
Manuel Kuran
2011-06-01
Full Text Available In the mid-twentieth century cognitive learning theories appeared as a criticism of behaviourism, and were later replaced by constructivist and connectivist learning theories. In the last two decades psychological research into cognition experienced a revival thanks to new methodological possibilities. This article brings a selection of research studies related to adult edu- cation in various ways: post-formal cognitive development stage, cognitive ageing, the meaning of crystallized intelligence in adulthood, and research into learning styles. The article proceeds with an account of research of literacy in vulnerable social groups and ends with a final chapter, which brings useful findings for researchers and adult education practitioners. In this article, the author has drawn from two separate sources. The first source are the professional premises underlying conceptualization of multi-media contents, prepared by the Slovenian Institute for Adult Education within the framework of the project titled Literacy development, and Assessment and Acknowledgement of Non-formal Learning between 2009 – 2011. The theoretical part of the underlying professional premises dealt, among other, with cognitive aspects of adult learning, which represent the basis of this article. The second source is the authorØs personal involvement in the field of cognitive psychology, or rather, in the field of cognitive sciences, in which even today learning and education of vulnerable groups of adults is given only marginal consideration in research.
Applying attachment theory to effective practice with hard-to-reach youth: the AMBIT approach.
Bevington, Dickon; Fuggle, Peter; Fonagy, Peter
2015-01-01
Adolescent Mentalization-Based Integrative Treatment (AMBIT) is a developing approach to working with "hard-to-reach" youth burdened with multiple co-occurring morbidities. This article reviews the core features of AMBIT, exploring applications of attachment theory to understand what makes young people "hard to reach," and provide routes toward increased security in their attachment to a worker. Using the theory of the pedagogical stance and epistemic ("pertaining to knowledge") trust, we show how it is the therapeutic worker's accurate mentalizing of the adolescent that creates conditions for new learning, including the establishment of alternative (more secure) internal working models of helping relationships. This justifies an individual keyworker model focused on maintaining a mentalizing stance toward the adolescent, but simultaneously emphasizing the critical need for such keyworkers to remain well connected to their wider team, avoiding activation of their own attachment behaviors. We consider the role of AMBIT in developing a shared team culture (shared experiences, shared language, shared meanings), toward creating systemic contexts supportive of such relationships. We describe how team training may enhance the team's ability to serve as a secure base for keyworkers, and describe an innovative approach to treatment manualization, using a wiki format as one way of supporting this process.
Kotasthane, Anuja; Mulakala, Chandrika; Viswanadhan, Vellarkad N
2014-03-01
The emerging picture of biomolecular recognition is that of conformational selection followed by induced-fit. Conformational selection theory states that binding partners exist in various conformations in solution, with binding involving a "selection" between complementary conformers. In this study, we devise a docking protocol that mimics conformational selection in protein-ligand binding and demonstrate that it significantly enhances crossdocking accuracy over Glide's flexible docking protocol, which is widely used in the pharmaceutical industry. Our protocol uses a pregenerated conformational ensemble to simulate ligand flexibility. The ensemble was generated by thorough conformational sampling coupled with conformer minimization. The generated conformers were then rigidly docked in the active site of the protein along with a postdocking minimization step that allows limited induced fit effects to be modeled for the ligand. We illustrate the improved performance of our protocol through crossdocking of 31 ligands to cocomplexed proteins of the kinase 3-phosphoinositide dependent protein kinase-1 extracted from the crystal structures 1H1W (ATP bound), 1OKY (staurosporine bound) and 3QD0 (bound to a potent inhibitor). Consistent with conformational selection theory, the performance of our protocol was the best for crossdocking to the cognate protein bound to the natural ligand, ATP. Copyright © 2013 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Mingzhan Huang
2014-01-01
Full Text Available Two predator-prey models with nonmonotonic functional response and state-dependent impulsive harvesting are formulated and analyzed. By using the geometry theory of semicontinuous dynamic system, we obtain the existence, uniqueness, and stability of the periodic solution and analyse the dynamic phenomenon of homoclinic bifurcation of the first system by choosing the harvesting rate β as control parameter. Besides, we also study the homoclinic bifurcation of the second system about parameter δ on the basis of the theory of rotated vector field. Finally, numerical simulations are presented to illustrate the results.
Rydon-Grange, Michelle
2015-11-01
The National Health Service (NHS) has, for over four decades, been beset with numerous 'scandals' relating to poor patient care across several diverse clinical contexts. Ensuing inquiries proceed as though each scandal is unique, with recommendations highlighting the need for more staff training, a change of culture within the NHS based upon a 'duty of candour', and proposed criminal sanctions for employees believed to breach good patient care. However, mistakes reoccur and failings in patient safety continue. While inquiries describe what went awry in each case, questions of how and why such failures came to be remain unanswered. Psychology has a role in answering these questions. Applying psychological theory can guide an understanding of the causes that lead to catastrophic failures in healthcare settings. Indeed, what is often neglected in inquiries is the role of human behaviour in contributing to these failures. Drawing upon behavioural, social and cognitive theories, a psychological analysis of key factors, typically present in clinical contexts where serious failures of care occur, is presented. Applying theory and models from the field of psychology can guide further understanding of the precipitants to poor care. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Robinson, H Fiona; Dennick, Reg
2015-06-01
This review was carried out to highlight relevant learning theory and its application to the teaching of endoscopic skills to speech and language therapists (SLTs). This article explains the most relevant models from Constructivist, Experiential and Humanistic Learning Theory, a combination that has been described as Constructive Experience, and describes the relevance and the benefits of applying educational frameworks in course design. This approach has been formally used to design and deliver practical skills teaching in medicine. SLTs carry out endoscopic evaluation of the larynx (EEL) to provide information for evaluation and rehabilitation of voice and swallowing disorders. These are essential procedures in ear, nose and throat, voice and swallowing specialist centres. Training in endoscopy skills for SLTs working in the ear, nose and throat specialist centres in the United Kingdom has traditionally been provided external to the local clinic environment as 1 or 2-day courses. In one survey in the United Kingdom, 79% of SLTs reported that they did not acquire the depth of skill required to carry out EEL autonomously after attending such courses. Course development to teach practical skills should be underpinned by educational theory. One EEL course in the United Kingdom is described, wherein sessions are interactive and experiential, promoting deep learning, constructive feedback and reflection, enriched by the completion of logs and portfolios. From course evaluations, all the learners met the learning objectives, developing and applying skills to become confident endoscopists in autonomous clinical practice.
Transgender Youth and Suicidal Behaviors: Applying the Interpersonal Psychological Theory of Suicide
Grossman, Arnold H.; Park, Jung Yeon; Russell, Stephen T.
2016-01-01
The interpersonal psychological theory of suicide (IPTS) was used to examine suicidal thoughts and behaviors among 129 transgender and gender nonconforming (TGNC) youth. Youth were categorized according to their gender identities: female-to-male (FTM), male-to-female (MTF), female-to-different-gender (FTDG), and male-to-different gender (MTDG). Higher percentages of suicidal ideation were reported by FTDG and FTM youth; and higher percentages of suicide attempts by FTDG and MTDG youth. Perceived burdensomeness and thwarted belongingness were significantly related to suicidal ideation and/or suicide attempts. Experiences of painful, provocative and harmful events and acquired capability significantly predicted suicide attempts. The findings support IPTS in explaining suicidal behaviors among TGNC youth. Implications for prevention and intervention efforts are discussed. PMID:28344728
Hart, Michael G; Ypma, Rolf J F; Romero-Garcia, Rafael; Price, Stephen J; Suckling, John
2016-06-01
Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brain's wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging. In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery. Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology.
[Applying energy theory to compare community health assessments conducted in urban and rural areas].
Liou, Yiing-Mei; Wang, Chia-Wen; Hung, Wen-Jing; Lin, Yu-Chi
2009-02-01
Taiwan's high population density frequently blurs the administrative boundaries between communities, leading to indistinct community identifications among the population. The authors used the Helvie energy theory to assess different communities in Taiwan, employing a core (population), four internal energies (chemical, physical, biological, and psychiatric) and nine environment subsystems (transportation, health, education, entertainment, economy, politics, communication, culture, and welfare) in an analysis of urban and rural community samples. Authors found significantly different influences on community health due to different environments and energy exchange factors between the two samples. Urban and rural communities have advantages and requirements that are distinct from one another. The community health nurse (CHN) should consider the specific demands of each community and develop professional roles to incorporate the three degrees of prevention. Authors hope that this article can inspire CHNs to define the critical health problems in their communities, facilitate the development of advanced professional roles, and serve as reference in implementing health plans.
Appraisal Theory applied to the wine tasting sheet in English and Spanish
Directory of Open Access Journals (Sweden)
Bozena Wislocka Breit
2014-03-01
Full Text Available The main goal of this study is the application of Appraisal Theory (Martin & White, 2005 developed in the framework of Systemic Functional Linguistics to wine tasting sheets. Firstly, whether this text type meets the defining requirements specified by Swales (1990 for the discursive genre will be verified. 110 tasting sheets in Spanish and English extracted from the Internet have been grouped into four corpora corresponding to the country of origin of the wine: Spain, Australia, California and New Zealand. An analysis undertaken with WordSmith Tools has demonstrated the positive polarization of all the texts and the existence of cultural differences reflected in the use of fruit-related terms, adjectives oenological terms and “oenological culturemes” (Wislocka Breit, 2012. An unforeseen result of the study was the strong contrast observed between the free and literary manner of the English and the concise style of Spanish tasting sheets.
Epitropaki, Olga; Martin, Robin
2004-04-01
The present empirical investigation had a 3-fold purpose: (a) to cross-validate L. R. Offermann, J. K. Kennedy, and P. W. Wirtz's (1994) scale of Implicit Leadership Theories (ILTs) in several organizational settings and to further provide a shorter scale of ILTs in organizations; (b) to assess the generalizability of ILTs across different employee groups, and (c) to evaluate ILTs' change over time. Two independent samples were used for the scale validation (N1 = 500 and N2 = 439). A 6-factor structure (Sensitivity, Intelligence, Dedication, Dynamism, Tyranny, and Masculinity) was found to most accurately represent ELTs in organizational settings. Regarding the generalizability of ILTs, although the 6-factor structure was consistent across different employee groups, there was only partial support for total factorial invariance. Finally, evaluation of gamma, beta, and alpha change provided support for ILTs' stability over time.
Theory of Visual Attention (TVA) applied to mice in the 5-choice serial reaction time task
DEFF Research Database (Denmark)
Fitzpatrick, C. M.; Caballero-Puntiverio, M.; Gether, U.
2017-01-01
modelled using a new three-parameter version of TVA to obtain estimates of visual processing speeds, visual thresholds and motor response baselines in each mouse. Results The parameter estimates for each animal were reliable across sessions, showing that the data were stable enough to support analysis......Rationale The 5-choice serial reaction time task (5-CSRTT) is widely used to measure rodent attentional functions. In humans, many attention studies in healthy and clinical populations have used testing based on Bundesen’s Theory of Visual Attention (TVA) to estimate visual processing speeds...... on an individual level. Scopolamine HBr dose-dependently reduced 5-CSRTT attentional performance while also increasing reward collection latency at the highest dose. Upon TVA modelling, scopolamine HBr significantly reduced visual processing speed at both doses, while having less pronounced effects on visual...
The theory of loss of chance in medical liability applied within Brazilian jurisprudence.
Beraldo, Anna de Moraes Salles; Pereira, Paula Moura Francesconi de Lemos
2012-06-01
The loss of chance doctrine arose in order to ensure full recovery of damages for the victims of medical negligence. In the doctor-patient relationship, the doctor performance may harm the patient in many different ways, giving rise to a range of injuries of different nature, including the injury caused by loss of the chance of cure or survival, which directly affects the patients' lives and health. Although this theory is not found in any enacted Brazilian law, and despite the resistance to its implementation due to the difficulty of its measurement and the calculation of the monetary damages, a gradual advancement in the application of the concept has been observed in recent years, showing that the Right to protect the dignity of the human person has been increasingly witnessed in Brazilian Courts.
Problems with change in R2 as applied to theory of reasoned action research.
Trafimow, David
2004-12-01
The paradigm of choice for theory of reasoned action research seems to depend largely on the notion of change in variance accounted for (DeltaR2) as new independent variables are added to a multiple regression equation. If adding a particular independent variable of interest increases the variance in the dependent variable that can be accounted for by the list of independent variables, then the research is deemed to be 'successful', and the researcher is considered to have made a convincing argument about the importance of the new variable. In contrast to this trend, I present arguments that suggest serious problems with the paradigm, and conclude that studies on attitude-behaviour relations would advance the field of psychology to a far greater extent if researchers abandoned it.
MADNESS applied to density functional theory in chemistry and nuclear physics
International Nuclear Information System (INIS)
Fann, G I; Harrison, R J; Beylkin, G; Jia, J; Hartman-Baker, R; Shelton, W A; Sugiki, S
2007-01-01
We describe some recent mathematical results in constructing computational methods that lead to the development of fast and accurate multiresolution numerical methods for solving quantum chemistry and nuclear physics problems based on Density Functional Theory (DFT). Using low separation rank representations of functions and operators in conjunction with representations in multiwavelet bases, we developed a multiscale solution method for integral and differential equations and integral transforms. The Poisson equation, the Schrodinger equation, and the projector on the divergence free functions provide important examples with a wide range of applications in computational chemistry, nuclear physics, computational electromagnetic and fluid dynamics. We have implemented this approach along with adaptive representations of operators and functions in the multiwavelet basis and low separation rank (LSR) approximation of operators and functions. These methods have been realized and implemented in a software package called Multiresolution Adaptive Numerical Evaluation for Scientific Simulation (MADNESS)
Richards, David A; Schat, Aaron C H
2011-01-01
In this article, we report the results of 2 studies that were conducted to investigate whether adult attachment theory explains employee behavior at work. In the first study, we examined the structure of a measure of adult attachment and its relations with measures of trait affectivity and the Big Five. In the second study, we examined the relations between dimensions of attachment and emotion regulation behaviors, turnover intentions, and supervisory reports of counterproductive work behavior and organizational citizenship behavior. Results showed that anxiety and avoidance represent 2 higher order dimensions of attachment that predicted these criteria (except for counterproductive work behavior) after controlling for individual difference variables and organizational commitment. The implications of these results for the study of attachment at work are discussed.
Brooks, Jessica M; Iwanaga, Kanako; Chiu, Chung-Yi; Cotton, Brandi Parker; Deiches, Jon; Morrison, Blaise; Moser, Erin; Chan, Fong
2017-08-01
This study examined the relationships between self-determination theory (SDT) and theory of planned behavior (TpB) applied to physical activity and exercise behavior (PA&E) in people with chronic pain. Two hundred and eleven adults with chronic musculoskeletal pain (28 males and 183 females, age range 18 to 82 years, mean age 43 years) were recruited from online support groups and clinic networks in the United States. Participants completed SDT measures relevant to PA&E on perceived autonomy support, autonomy, competence, and relatedness, as well as TpB measures relevant to PA&E on intention, attitudes, subjective norms, and perceived behavioral control. Correlational techniques and canonical correlation analysis were performed to examine the relationships and variance within and between theoretical dimensions. Overall, the SDT set accounted for 37% of the TpB variance and the TpB set accounted for 32% of the SDT set variance. The results indicate there are statistical similarities and differences between concepts in SDT and TpB models for PA&E. Using both empirical guidance and clinical expertise, researchers and practitioners should attempt to select and integrate non-redundant and complementary components from SDT, TpB, and other related health behavior theories.
Assessing landslide susceptibility by applying fuzzy sets, possibility evidence-based theories
Directory of Open Access Journals (Sweden)
Ibsen Chivatá Cárdenas
2008-01-01
Full Text Available A landslide susceptibility model was developed for the city of Manizales, Colombia; landslides have been the city’s main environmental problem. Fuzzy sets and possibility and evidence-based theories were used to construct the mo-del due to the set of circumstances and uncertainty involved in the modelling; uncertainty particularly concerned the lack of representative data and the need for systematically coordinating subjective information. Susceptibility and the uncertainty were estimated via data processing; the model contained data concerning mass vulnerability and uncer-tainty. Output data was expressed on a map defined by linguistic categories or uncertain labels as having low, me-dium, high and very high susceptibility; this was considered appropriate for representing susceptibility. A fuzzy spec-trum was developed for classifying susceptibility levels according to perception and expert opinion. The model sho-wed levels of susceptibility in the study area, ranging from low to high susceptibility (medium susceptibility being mo-re frequent. This article shows the details concerning systematic data processing by presenting theories and tools regarding uncertainty. The concept of fuzzy parameters is introduced; this is useful in modelling phenomena regar-ding uncertainty, complexity and nonlinear performance, showing that susceptibility modelling can be feasible. The paper also shows the great convenience of incorporating uncertainty into modelling and decision-making. However, quantifying susceptibility is not suitable when modelling identified uncertainty because incorporating model output information cannot be reduced into exact or real numerical quantities when the nature of the variables is particularly uncertain. The latter concept is applicable to risk assessment.
Games in the Arctic: applying game theory insights to Arctic challenges
Directory of Open Access Journals (Sweden)
Scott Cole
2014-08-01
Full Text Available We illustrate the benefits of game theoretic analysis for assisting decision-makers in resolving conflicts and other challenges in a rapidly evolving region. We review a series of salient Arctic issues with global implications—managing open-access fisheries, opening Arctic areas for resource extraction and ensuring effective environmental regulation for natural resource extraction—and provide insights to help reach socially preferred outcomes. We provide an overview of game theoretic analysis in layman's terms, explaining how game theory can help researchers and decision-makers to better understand conflicts, and how to identify the need for, and improve the design of, policy interventions. We believe that game theoretic tools are particularly useful in a region with a diverse set of players ranging from countries to firms to individuals. We argue that the Arctic Council should take a more active governing role in the region by, for example, dispersing information to “players” in order to alleviate conflicts regarding the management of common-pool resources such as open-access fisheries and natural resource extraction. We also identify side payments—that is, monetary or in-kind compensation from one party of a conflict to another—as a key mechanism for reaching a more biologically, culturally and economically sustainable Arctic future. By emphasizing the practical insights generated from an academic discipline, we present game theory as an influential tool in shaping the future of the Arctic—for individual researchers, for inter-disciplinary research and for policy-makers themselves.
Applied string theory, hot and cold. A holographic view on quark-gluon plasma and superfluids
Energy Technology Data Exchange (ETDEWEB)
Samberg, Andreas Wilhelm
2015-12-21
This thesis deals with applications of gauge/gravity duality to strong-coupling phenomena in the quark-gluon plasma and far-from-equilibrium superfluids. In a first part we search for model-independent (universal) behavior in various non-Abelian gauge-theory plasmas at finite temperature and chemical potential. We employ the holographic duals of strongly coupled N=4 supersymmetric Yang-Mills theory and three one-parameter families of non-conformal deformations thereof, two of which solve the equations of motion of a five-dimensional Einstein-Maxwell-scalar action. We study the free energy and associated thermodynamic quantities of heavy quarks and bound quark-anti-quark (Q anti Q) pairs as well as the Q anti Q binding energy and the running coupling. We find qualitative agreement with available lattice QCD data. Moreover, we show that several observables exhibit universal behavior for all values of the chemical potential. In a second part we investigate the real-time dynamics of a bosonic superfluid in two spatial dimensions after initial quenches that take the system to far-from-equilibrium states characterized by many topological vortex defects in association with quantum turbulence. To this end we numerically solve the full equations of motion of the holographically dual Abelian Higgs model on four-dimensional anti-de Sitter space. We observe a universal non-equilibrium late-time regime characterized by power-law behavior in a two-point correlation function and in characteristic length scales, which we interpret as a non-thermal fixed point.
Applying complexity theory: A primer for identifying and modeling firm anomalies
Directory of Open Access Journals (Sweden)
Arch G. Woodside
2018-01-01
Full Text Available This essay elaborates on the usefulness of embracing complexity theory, modeling outcomes rather than directionality, and modeling complex rather than simple outcomes in strategic management. Complexity theory includes the tenet that most antecedent conditions are neither sufficient nor necessary for the occurrence of a specific outcome. Identifying a firm by individual antecedents (i.e., non-innovative versus highly innovative, small versus large size in sales or number of employees, or serving local versus international markets provides shallow information in modeling specific outcomes (e.g., high sales growth or high profitability—even if directional analyses (e.g., regression analysis, including structural equation modeling indicates that the independent (main effects of the individual antecedents relate to outcomes directionally—because firm (case anomalies almost always occur to main effects. Examples: a number of highly innovative firms have low sales while others have high sales and a number of non-innovative firms have low sales while others have high sales. Breaking-away from the current dominant logic of directionality testing—null hypotheses statistic testing (NHST—to embrace somewhat precise outcome testing (SPOT is necessary for extracting highly useful information about the causes of anomalies—associations opposite to expected and “statistically significant” main effects. The study of anomalies extends to identifying the occurrences of four-corner strategy outcomes: firms doing well in favorable circumstances, firms doing badly in favorable circumstances, firms doing well in unfavorable circumstances, and firms doing badly in unfavorable circumstances. Models of four-corner strategy outcomes advances strategic management beyond the current dominant logic of directional modeling of single outcomes.
Applied string theory, hot and cold. A holographic view on quark-gluon plasma and superfluids
International Nuclear Information System (INIS)
Samberg, Andreas Wilhelm
2015-01-01
This thesis deals with applications of gauge/gravity duality to strong-coupling phenomena in the quark-gluon plasma and far-from-equilibrium superfluids. In a first part we search for model-independent (universal) behavior in various non-Abelian gauge-theory plasmas at finite temperature and chemical potential. We employ the holographic duals of strongly coupled N=4 supersymmetric Yang-Mills theory and three one-parameter families of non-conformal deformations thereof, two of which solve the equations of motion of a five-dimensional Einstein-Maxwell-scalar action. We study the free energy and associated thermodynamic quantities of heavy quarks and bound quark-anti-quark (Q anti Q) pairs as well as the Q anti Q binding energy and the running coupling. We find qualitative agreement with available lattice QCD data. Moreover, we show that several observables exhibit universal behavior for all values of the chemical potential. In a second part we investigate the real-time dynamics of a bosonic superfluid in two spatial dimensions after initial quenches that take the system to far-from-equilibrium states characterized by many topological vortex defects in association with quantum turbulence. To this end we numerically solve the full equations of motion of the holographically dual Abelian Higgs model on four-dimensional anti-de Sitter space. We observe a universal non-equilibrium late-time regime characterized by power-law behavior in a two-point correlation function and in characteristic length scales, which we interpret as a non-thermal fixed point.
A codimension two bifurcation in a railway bogie system
DEFF Research Database (Denmark)
Zhang, Tingting; True, Hans; Dai, Huanyun
2017-01-01
coexist in a range of the bifurcation parameters which can lead to jumps in the lateral oscillation amplitude of the railway bogie system. Furthermore, reduce the values of the bifurcation parameters gradually. Firstly, the supercritical Hopf bifurcation turns into a subcritical one with multiple limit......In this paper, a comprehensive analysis is presented to investigate a codimension two bifurcation that exists in a nonlinear railway bogie dynamic system combining theoretical analysis with numerical investigation. By using the running velocity V and the primary longitudinal stiffness (Formula...... presented.) as bifurcation parameters the first and second Lyapunov coefficients are calculated to determine which kind of Hopf bifurcation can happen and how the system states change with the variance of the bifurcation parameters. It is found that multiple solution branches both stable and unstable...
Stochastic bifurcation in a model of love with colored noise
Yue, Xiaokui; Dai, Honghua; Yuan, Jianping
2015-07-01
In this paper, we wish to examine the stochastic bifurcation induced by multiplicative Gaussian colored noise in a dynamical model of love where the random factor is used to describe the complexity and unpredictability of psychological systems. First, the dynamics in deterministic love-triangle model are considered briefly including equilibrium points and their stability, chaotic behaviors and chaotic attractors. Then, the influences of Gaussian colored noise with different parameters are explored such as the phase plots, top Lyapunov exponents, stationary probability density function (PDF) and stochastic bifurcation. The stochastic P-bifurcation through a qualitative change of the stationary PDF will be observed and bifurcation diagram on parameter plane of correlation time and noise intensity is presented to find the bifurcation behaviors in detail. Finally, the top Lyapunov exponent is computed to determine the D-bifurcation when the noise intensity achieves to a critical value. By comparison, we find there is no connection between two kinds of stochastic bifurcation.
Sibley, Kathryn M; Salbach, Nancy M
2015-04-01
Knowledge translation (KT) is an emerging discipline with a focus on implementing health evidence in decision making and clinical practice. Knowledge translation theories provide conceptual frameworks that can direct research focused on optimizing best practice. The objective of this case report is to describe one prominent KT theory--the knowledge-to-action (KTA) framework--and how it was applied to research on balance and gait assessment in physical therapist practice. Valid and reliable assessment tools are recommended to evaluate balance and gait function, but gaps in physical therapy practices are known. The KTA framework's 2-pronged approach (knowledge creation phase and action cycle) guided research questions exploring current practices in balance and gait assessment and factors influencing practice in Ontario, Canada, with the goal of developing and evaluating targeted KT interventions. Results showed the rate at which therapists use standardized balance and gait tools was less than optimal and identified both knowledge-to-practice gaps and individual and organizational barriers to implementing best assessment practices. These findings highlighted the need for synthesis of evidence to address those gaps prior to the development of potential intervention strategies. The comprehensive KTA framework was useful in guiding the direction of these ongoing research programs. In both cases, the sequence of the individual KTA steps was modified to improve the efficiency of intervention development, there was a need to go back and forth between the 2 phases of the KTA framework, and additional behavior change and barrier assessment theories were consulted. Continued research is needed to explicitly evaluate the efficacy of applying KT theory to best practice in health care. © 2015 American Physical Therapy Association.
Aspects of space charge theory applied to dielectric under electron beam irradiation
International Nuclear Information System (INIS)
Oliveira, L.N. de.
1975-01-01
Irradiation of solid dielectric with electron beams has been used as a power full tool in investigations of charge storage and transport in such materials. Some of the results that have been obtained in this area are reviewed and the formulation of a transport equation for excess charge in irradiated insulators is dicussed. This equation is subsequently applied to various experimental set-ups. It is found that space charge effects play an essential role in the establishment of stationary currents in samples subject to quasi-penetrating electron beams. Such effects may, however, be neglected for low electron ranges. Theoretical results are in good agreement with experimental findings by Spear (1955)
Thomas, Tracy N; Sobelson, Robyn K; Wigington, Corinne J; Davis, Alyson L; Harp, Victoria H; Leander-Griffith, Michelle; Cioffi, Joan P
Interventions and media campaigns promoting household disaster preparedness have produced mixed results in affecting behaviors. In large part, this is due to the limited application of instructional design strategies and behavior theory, such as the Transtheoretical Model (TTM). This study describes the development and evaluation of Ready CDC, an intervention designed to increase household disaster preparedness among the Centers for Disease Control and Prevention (CDC) workforce. (1) Describe the instructional design strategies employed in the development of Ready CDC and (2) evaluate the intervention's impact on behavior change and factors influencing stage progression for household disaster preparedness behavior. Ready CDC was adapted from the Federal Emergency Management Agency's (FEMA's) Ready campaign. Offered to CDC staff September 2013-November 2015, it consisted of a preassessment of preparedness attitudes and behaviors, an in-person training, behavioral reinforcement communications, and a 3-month follow-up postassessment. Ready CDC employed well-accepted design strategies, including presenting stimulus material and enhancing transfer of desired behavior. Excluding those in the TTM "maintenance" stage at baseline, this study determined 44% of 208 participants progressed at least 1 stage for developing a written disaster plan. Moreover, assessment of progression by stage found among participants in the "precontemplation" (n = 16), "contemplation" (n = 15), and "preparation" (n = 125) stages at baseline for assembling an emergency kit, 25%, 27%, and 43% moved beyond the "preparation" stage, respectively. Factors influencing stage movement included knowledge, attitudes, and community resiliency but varied depending on baseline stage of change. Employing instructional strategies and behavioral theories in preparedness interventions optimizes the potential for individuals to adopt preparedness behaviors. Study findings suggest that stage movement toward
Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N
2017-09-19
How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox
The theory of planned behavior as applied to preoperative smoking abstinence.
Shi, Yu; Ehlers, Shawna; Warner, David O
2014-01-01
Abstinence from smoking on the morning of surgery may improve outcomes. This study examined the explicatory power of the Theory of Planned Behavior (TPB) to predict smoking behavior on the morning of surgery, testing the hypothesis that the constructs of attitude, subjective norm, and perceived behavioral control (PBC) will predict intent to abstain from smoking the morning of surgery, and that intent will predict behavior. TPB constructs were assessed in 169 pre-surgical patients. Smoking behavior on the morning of surgery was assessed by self-report and CO monitoring. Correlations and structural equation modeling (SEM) were used to determine associations between measures and behavior. All TPB measures, including intent as predicted by the TPB, were correlated with both a lower rate of self-reported smoking on the morning of surgery and lower CO levels. The SEM showed a good fit to the data. In the SEM, attitude and PBC, but not subjective norm, were significantly associated with intent to abstain, explaining 46% of variance. The effect of PBC on CO levels was partially mediated by intent. The amount of variance in behavior explained by these TPB constructs was modest (10% for CO levels). Thus, attitude and perceived behavioral control explain a substantial portion of the intent to maintain preoperative abstinence on the morning of elective surgery, and intent and perceived behavioral control explain a more modest but significant amount of the variance in actual smoking behavior. Clinical Trials.gov registration: NCT01014455.
Applying the Theory of Work Adjustment to Latino Immigrant Workers: An Exploratory Study.
Eggerth, Donald E; Flynn, Michael A
2012-02-01
Blustein mapped career decision making onto Maslow's model of motivation and personality and concluded that most models of career development assume opportunities and decision-making latitude that do not exist for many individuals from low income or otherwise disadvantaged backgrounds. Consequently, Blustein argued that these models may be of limited utility for such individuals. Blustein challenged researchers to reevaluate current career development approaches, particularly those assuming a static world of work, from a perspective allowing for changing circumstances and recognizing career choice can be limited by access to opportunities, personal obligations, and social barriers. This article represents an exploratory effort to determine if the theory of work adjustment (TWA) might meaningfully be used to describe the work experiences of Latino immigrant workers, a group living with severe constraints and having very limited employment opportunities. It is argued that there is significant conceptual convergence between Maslow's hierarchy of needs and the work reinforcers of TWA. The results of an exploratory, qualitative study with a sample of 10 Latino immigrants are also presented. These immigrants participated in key informant interviews concerning their work experiences both in the United States and in their home countries. The findings support Blustein's contention that such workers will be most focused on basic survival needs and suggest that TWA reinforcers are descriptive of important aspects of how Latino immigrant workers conceptualize their jobs.
Caldwell, Kate; Harris, Sarah Parker; Renko, Maija
2012-12-01
Contemporary policy encourages self-employment and entrepreneurship as a vehicle for empowerment and self-sufficiency among people with disabilities. However, such encouragement raises important citizenship questions concerning the participation of people with intellectual and developmental disabilities (IDD). As an innovative strategy for addressing pressing social and economic problems, "social entrepreneurship" has become a phrase that is gaining momentum in the IDD community--one that carries with it a very distinct history. Although social entrepreneurship holds the potential to be an empowering source of job creation and social innovation, it also has the potential to be used to further disenfranchise this marginalized population. It is crucial that in moving forward society takes care not to perpetuate existing models of oppression, particularly in regard to the social and economic participation of people with IDD. The conceptual tools addressed in this article can inform the way that researchers, policymakers, and practitioners approach complex issues, such as social entrepreneurship, to improve communication among disciplines while retaining an integral focus on rights and social justice by framing this issue within citizenship theory.
Self-Determination Theory Applied to Health Contexts: A Meta-Analysis.
Ng, Johan Y Y; Ntoumanis, Nikos; Thøgersen-Ntoumani, Cecilie; Deci, Edward L; Ryan, Richard M; Duda, Joan L; Williams, Geoffrey C
2012-07-01
Behavior change is more effective and lasting when patients are autonomously motivated. To examine this idea, we identified 184 independent data sets from studies that utilized self-determination theory (SDT; Deci & Ryan, 2000) in health care and health promotion contexts. A meta-analysis evaluated relations between the SDT-based constructs of practitioner support for patient autonomy and patients' experience of psychological need satisfaction, as well as relations between these SDT constructs and indices of mental and physical health. Results showed the expected relations among the SDT variables, as well as positive relations of psychological need satisfaction and autonomous motivation to beneficial health outcomes. Several variables (e.g., participants' age, study design) were tested as potential moderators when effect sizes were heterogeneous. Finally, we used path analyses of the meta-analyzed correlations to test the interrelations among the SDT variables. Results suggested that SDT is a viable conceptual framework to study antecedents and outcomes of motivation for health-related behaviors. © The Author(s) 2012.
Applying the Theory of Planned Behavior in the Purchase of Organic Food
Directory of Open Access Journals (Sweden)
Linda Martić Kuran
2014-12-01
Full Text Available The main objective of the study was to define factors which influence the purchase intention involving organic food among Croatian consumers. In order to create a theoretical base, this research adopted the theory of planned behavior. The model examines the impact of several independent variables on the intention to purchase organic foods. The study was conducted on a sample of 331 respondents in the territory of Republic of Croatia. Research results indicate that consumer attitudes towards organic food, subjective norms, perceived financial situation, health awareness and knowledge about organic food have a significant impact on the intention involving the purchase of organic food, with subjective norms, attitudes and health awareness being the best predictors of the purchase intention. On the other hand, the relationship between the perceived availability of organic food and the intention to buy organic food was statistically significant. Considering the demographic characteristics of respondents and their correlation with the purchase intention, marital status, age and household income were found to significantly affect the intention to buy organic food, while other demographic variables had no significant impact on the purchase intention. Therefore, the respondents who are married, between 46 and 55 years old and with household incomes of more than 16,000 kuna show a greater intention to buy organic food in comparison with other respondents. The research results have important implications for marketing practice, primarily for advertising.
APPLYING THE THEORY OF CONSTRAINTS TO INCREASE ECONOMIC VALUE ADDED: PART 2—IMPLEMENTATION
Directory of Open Access Journals (Sweden)
M. Smith
2012-01-01
Full Text Available
ENGLISH ABSTRACT: This article describes a way to implement the holistic approach of the Theory of Constraints (TOC which will lead to an increase in the Economic Value Added (EVA of a business. The approach consists of two parts: the adoption of the holistic approach, and the implementation of a new company strategy. The pitfalls in implementing a holistic approach are discussed. The elements of a company strategy that is compatible with the holistic approach are described.
AFRIKAANSE OPSOMMING: Hierdie artikel beskryf ‘n metode hoe om die holistiese benadering van die Teorie van Beperkinge (TVB te implementeer met die doel om die Ekonomiese Toegevoegde Waarde (ETW van ’n besigheid te vermeerder. Die benadering is tweeledig: die ingebruikneming van die holistiese benadering, en die implementering van ’n nuwe besigheidsstrategie. Die moontlike probleme in die implementering van die holistiese benadering word bespreek. Die elemente van ’n besigheidsstrategie wat versoenbaar is met die holistiese benadering word beskryf.
Sargeant, Sally; McLean, Michelle; Green, Patricia; Johnson, Patricia
2017-03-01
In their journey to becoming doctors, students engage with a range of teachers and trainers. Among these are simulated patients (SPs), who, through role-playing, assist students to develop their communication and physical examination skills, in contexts of formative and summative assessments. This paper explores the teaching and learning relationship between medical students and SPs, and considers how this might affect feedback and assessment. 14 SPs were interviewed on the subject of medical students' professional identity development in 2014. Data were examined using narrative analysis in conjunction with positioning theory to identify the positions that SPs assigned to themselves and to students. Narrative analysis yielded three interpretative positioning themes: Occupational, familial and cultural and discursive and embodied positioning. The interview process revealed that SPs adopt different positions intra-and interpersonally. SPs appear to hold dissonant perceptions of students in terms relating to their emerging professional identities, which may confound assessment and feedback. Training should include reflections on the SP/student relationship to uncover potential biases and positions, giving SPs the opportunity to reflect on and manage their individual and occupational selves.
Rudberg, Elias
2012-02-01
Self-consistency-based Kohn-Sham density functional theory (KS-DFT) electronic structure calculations with Gaussian basis sets are reported for a set of 17 protein-like molecules with geometries obtained from the Protein Data Bank. It is found that in many cases such calculations do not converge due to vanishing HOMO-LUMO gaps. A sequence of polyproline I helix molecules is also studied and it is found that self-consistency calculations using pure functionals fail to converge for helices longer than six proline units. Since the computed gap is strongly correlated to the fraction of Hartree-Fock exchange, test calculations using both pure and hybrid density functionals are reported. The tested methods include the pure functionals BLYP, PBE and LDA, as well as Hartree-Fock and the hybrid functionals BHandHLYP, B3LYP and PBE0. The effect of including solvent molecules in the calculations is studied, and it is found that the inclusion of explicit solvent molecules around the protein fragment in many cases gives a larger gap, but that convergence problems due to vanishing gaps still occur in calculations with pure functionals. In order to achieve converged results, some modeling of the charge distribution of solvent water molecules outside the electronic structure calculation is needed. Representing solvent water molecules by a simple point charge distribution is found to give non-vanishing HOMO-LUMO gaps for the tested protein-like systems also for pure functionals.
Zhu, Wuming; Toulouse, Julien; Savin, Andreas; Angyán, János G
2010-06-28
Range-separated methods combining a short-range density functional with long-range random phase approximations (RPAs) with or without exchange response kernel are tested on rare-gas dimers and the S22 benchmark set of weakly interacting complexes of Jurecka et al. [Phys. Chem. Chem. Phys. 8, 1985 (2006)]. The methods are also compared to full-range RPA approaches. Both range separation and inclusion of the Hartree-Fock exchange kernel largely improve the accuracy of intermolecular interaction energies. The best results are obtained with the method called RSH+RPAx, which yields interaction energies for the S22 set with an estimated mean absolute error of about 0.5-0.6 kcal/mol, corresponding to a mean absolute percentage error of about 7%-9% depending on the reference interaction energies used. In particular, the RSH+RPAx method is found to be overall more accurate than the range-separated method based on long-range second-order Moller-Plesset (MP2) perturbation theory (RSH+MP2).
Eliashberg theory applied to the study of an Nb-Ge series
International Nuclear Information System (INIS)
Baquero, R.; Gutierrez-Ibarra, J.; Kihlstrom, K.E.
1991-07-01
We use strong coupling theory of superconductivity to perform a detailed analysis of the Eliashberg functions α 2 F(ω), for thirteen samples of Nb-Ge with critical temperatures ranging from 7.0 K to 21.1K. As critical temperature increases, we analyze the general trends of the electron-phonon coupling parameter λ, of the integral of α 2 F(ω)''A'', and of other characteristics of α 2 F(ω) on the basis of qualitative or empirical criteria. While we find that the samples have in general the behavior expected, a closer analysis points to an overall attenuation in α 2 F(ω) of unclear origin. Though the gap edge, Δ 0 , appears to be well described by the α 2 F(ω) obtained, the thermodynamic critical field agrees poorly with that reproduced by α 2 F(ω) in the only case where the necessary (tunneling α 2 F(ω), critical field measurements) data are available. Our analysis suggests there is a gross uncertainty in the measured H c (0). The overall analysis shows that the samples obtained are of enough quality to already give meaningful results upon inversion of the tunneling data. (author). 23 refs, 14 figs, 6 tabs
Applying the cognitive theory of multimedia learning: an analysis of medical animations.
Yue, Carole; Kim, Jessie; Ogawa, Rikke; Stark, Elena; Kim, Sara
2013-04-01
Instructional animations play a prominent role in medical education, but the degree to which these teaching tools follow empirically established learning principles, such as those outlined in the cognitive theory of multimedia learning (CTML), is unknown. These principles provide guidelines for designing animations in a way that promotes optimal cognitive processing and facilitates learning, but the application of these learning principles in current animations has not yet been investigated. A large-scale review of existing educational tools in the context of this theoretical framework is necessary to examine if and how instructional medical animations adhere to these principles and where improvements can be made. We conducted a comprehensive review of instructional animations in the health sciences domain and examined whether these animations met the three main goals of CTML: managing essential processing; minimising extraneous processing, and facilitating generative processing. We also identified areas for pedagogical improvement. Through Google keyword searches, we identified 4455 medical animations for review. After the application of exclusion criteria, 860 animations from 20 developers were retained. We randomly sampled and reviewed 50% of the identified animations. Many animations did not follow the recommended multimedia learning principles, particularly those that support the management of essential processing. We also noted an excess of extraneous visual and auditory elements and few opportunities for learner interactivity. Many unrealised opportunities exist for improving the efficacy of animations as learning tools in medical education; instructors can look to effective examples to select or design animations that incorporate the established principles of CTML. © Blackwell Publishing Ltd 2013.
Assessment of learning powered mobility use--applying grounded theory to occupational performance.
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.
International Nuclear Information System (INIS)
Murphy, Glen D.
2009-01-01
The continued reliance of manual data capture in engineering asset intensive organisations highlights the critical role played by those responsible for recording raw data. The potential for data quality variance across individual operators also exposes the need to better manage this particular group. This paper evaluates the relative importance of the human factors associated with data quality. Using the theory of planned behaviour this paper considers the impact of attitudes, perceptions and behavioural intentions on the data collection process in an engineering asset context. Two additional variables are included, those of time pressure and operator feedback. Time pressure is argued to act as a moderator between intention and data collection behaviour, while perceived behavioural control will moderate the relationship between feedback and data collection behaviour. Overall the paper argues that the presence of best practice procedures or threats of disciplinary sanction are insufficient controls to determine data quality. Instead those concerned with improving the data collection performance of operators should consider the operator's perceptions of group attitude towards data quality, the level of feedback provided to data collectors and the impact of time pressures on procedure compliance. A range of practical recommendations are provided to those wishing to improve the quality of their manually acquired data.
Applying Learning Theory to Safety and Health Training for Hispanic Immigrant Dairy Workers.
Juárez-Carrillo, Patricia M; Liebman, Amy K; Reyes, Iris Anne C; Ninco Sánchez, Yurany V; Keifer, Matthew C
2017-07-01
We designed a safety and health curriculum for dairy immigrant workers aiming to increase knowledge, encourage safe behavior, and reduce worker communication inequalities to prevent occupational injury and diseases. The design is largely based on the Taxonomy of Significant Learning and incorporated behavioral and adult learning theories and principles of occupational hazard control. Trainings were implemented with 836 Spanish-speaking workers from 67 farms in Wisconsin. Sixty-seven percent of workers reported never being trained before in dairy safety, 65% of these worked in dairy for 5 or fewers years, and 26% of workers reported being ever injured while working on dairy. Quantitative and qualitative evaluation of the trainings suggest that our curriculum successfully increased worker knowledge and promoted contemplation of safe practices. The overall knowledge gain of 25% was statistically significant ( p behavior, and mentioned their intention to communicate safety concerns to farmers. To our knowledge, this is the first Taxonomy of Significant Learning application to occupational safety and health education. Our curriculum can support dairy farmers' compliance with Occupational Safety and Health Administration's annual training requirements by providing our basic safety and health training to workers at early job stages.
Applying Game Theory and Time Series in Smith Travel Accommodation Resort (STAR
Directory of Open Access Journals (Sweden)
Xuan TRAN
2016-12-01
Full Text Available Although Smith Travel Accommodations Report (STAR benchmarks hotel performance against its competitive aggregate and local markets, hotel managers consider STAR as a reference document rather than a strategy model for hotel competition. Recent research report managers prefer less information to use it as clues for a decision rather than more information not to be able to make a decision. It is imperative for hotel managers to use STAR as a clue for the competition. Limited research has focused on techniques to build a clue for STAR as a practice strategy. The present study has built two matrices by STAR indices. After that, game theory strategies were conducted to forecast the outcomes whenever hotel mangers change price. A sample of hotel guests who stayed in seven top hotel destinations in the U.S. during the ten-year period (2005-2015 was selected in the scenario with two assumptions: (1 there are two players in the U.S. meeting business: Player 1 includes hoteliers in Washington DC, Virginia, and Maryland and player 2 includes hoteliers in Orlando, Los Angeles, Chicago, and New York and (2 customers in a hotel of player 1 prefer staying in the hotel of player 1 rather than staying in the hotel of player 2 and vice versa. Findings indicate that two matrices have provided hoteliers with simple clues of different strategies in each month during the year to maximize their revenue.
Experimental Bifurcation Analysis Using Control-Based Continuation
DEFF Research Database (Denmark)
Bureau, Emil; Starke, Jens
The focus of this thesis is developing and implementing techniques for performing experimental bifurcation analysis on nonlinear mechanical systems. The research centers around the newly developed control-based continuation method, which allows to systematically track branches of stable and unsta......The focus of this thesis is developing and implementing techniques for performing experimental bifurcation analysis on nonlinear mechanical systems. The research centers around the newly developed control-based continuation method, which allows to systematically track branches of stable...... procedure is applied to our test rig, resulting in a reliable non-invasive, locally stabilizing control. The use of stabilizing control makes it difficult to determine the stability of the underlying uncontrolled equilibrium. Based on the idea of momentarily modifying or disabling the control and study...... the resulting behavior, we propose and test three different methods for assessing stability of equilibrium states during experimental continuation. We show that it is possible to determine the stability without allowing unbounded divergence, and that it is under certain circumstances possible to quantify...
Local viscosity distribution in bifurcating microfluidic blood flows
Kaliviotis, E.; Sherwood, J. M.; Balabani, S.
2018-03-01
The red blood cell (RBC) aggregation phenomenon is majorly responsible for the non-Newtonian nature of blood, influencing the blood flow characteristics in the microvasculature. Of considerable interest is the behaviour of the fluid at the bifurcating regions. In vitro experiments, using microchannels, have shown that RBC aggregation, at certain flow conditions, affects the bluntness and skewness of the velocity profile, the local RBC concentration, and the cell-depleted layer at the channel walls. In addition, the developed RBC aggregates appear unevenly distributed in the outlets of these channels depending on their spatial distribution in the feeding branch, and on the flow conditions in the outlet branches. In the present work, constitutive equations of blood viscosity, from earlier work of the authors, are applied to flows in a T-type bifurcating microchannel to examine the local viscosity characteristics. Viscosity maps are derived for various flow distributions in the outlet branches of the channel, and the location of maximum viscosity magnitude is obtained. The viscosity does not appear significantly elevated in the branches of lower flow rate as would be expected on the basis of the low shear therein, and the maximum magnitude appears in the vicinity of the junction, and towards the side of the outlet branch with the higher flow rate. The study demonstrates that in the branches of lower flow rate, the local viscosity is also low, helping us to explain why the effects of physiological red blood cell aggregation have no adverse effects in terms of in vivo vascular resistance.
Applied data-centric social sciences concepts, data, computation, and theory
Sato, Aki-Hiro
2014-01-01
Applied data-centric social sciences aim to develop both methodology and practical applications of various fields of social sciences and businesses with rich data. Specifically, in the social sciences, a vast amount of data on human activities may be useful for understanding collective human nature. In this book, the author introduces several mathematical techniques for handling a huge volume of data and analysing collective human behaviour. The book is constructed from data-oriented investigation, with mathematical methods and expressions used for dealing with data for several specific problems. The fundamental philosophy underlying the book is that both mathematical and physical concepts are determined by the purposes of data analysis. This philosophy is shown throughout exemplar studies of several fields in socio-economic systems. From a data-centric point of view, the author proposes a concept that may change people’s minds and cause them to start thinking from the basis of data. Several goals underlie ...
Posters that foster cognition in the classroom: Multimedia theory applied to educational posters
Hubenthal, M.; O'Brien, T.; Taber, J.
2011-12-01
Despite a decline in popularity within U.S. society, posters continue to hold a prominent place within middle and high school science classrooms. Teachers' demand for posters is largely satisfied by governmental and non-profit science organizations' education and public outreach (EPO) efforts. Here, posters are produced and disseminated as both tangible products resulting from the organization's research, and instruments to communicate scientific content to teachers and students. This study investigates the taken-for-granted good of posters through a survey/interview of science teachers who received sample posters at professional development workshops. The design of sample EPO posters were also examined for their implied, underlying assumptions about learning and their alignment to the setting of the classroom, which is unique for the genera of posters. Based on this analysis we found that rates of poster use were as low as 43% and that many EPO posters fail to achieve their potential as an instructional instrument. As a result, many EPO posters are relegated to merely a collection of pretty pictures on the wall. Leveraging existing research in both cognition and the cognitive theory of Multimedia learning, we propose a design framework for educational posters that is likely to activate students' attention, catalyze cognitive processing, provide a framework to guide students' construction of knowledge, and connect to extended learning through live or web-based exploration of phenomenon. While work to examine the implications of this framework is still on-going, we present a prototype poster and supporting website developed using the framework as a guide, as well as results from focus group discussions with classroom practitioners regarding the prototype poster and its potential in the classroom.
Clough, R W; Lehr, R P
1996-01-01
The traditional gross anatomy laboratory experience, with modifications in evaluations that we outline later, meets the criteria of contextual-learning theory, expands the repertoire of core objectives we identify for our students, and may increase the likelihood of cognitive permanence of anatomical data. Our subjects included approximately 54 first-year medical students from each of three sequential class years (1996, 1997, 1998). As an alternative to more typical written and practical exams, examinations in a major portion of our gross anatomy program consist of two approximately 30 minute oral expositions by each student to his or her peers and a faculty member. Students demonstrate specific detail on cadaver, x-ray, cross sections, or a model. Clinical applications, spatial relationships, nomenclature, and functions are strongly emphasized. The results of this teaching approach to the utilization of anatomical knowledge in clinical situations requires further assessment: however, new attributes have been afforded our students with implementation of the present program: First, students learn anatomical detail equally well as the students of the more traditional system (based on board exam results). Second, students who completed the program indicate that this approach provides a useful simulation of what is expected later in their training. Third, students gradually gain confidence in verbal presentation, they demonstrate cognitive synthesis of separate conceptual issues, they retain information, and they are quite visibly more enthusiastic about anatomy and its importance in medicine. Our program demonstrates that the learning of applicable human anatomy is facilitated in a contextual-learning environment. Moreover, by learning anatomy in this way, other equally beneficial attributes are afforded the medical student, including, but not limited to, increases in communication skills, confidence in verbal presentation, synthesis of anatomical concepts
Palat, Blazej; Paran, Françoise; Delhomme, Patricia
2017-01-01
Based on an extended Theory of Planned Behavior (TPB, Ajzen, 1985, 1991), we conducted surveys in order to explain and predict violations at a railroad crossing, among pedestrians (n=153) and car drivers (n=151). Measures were made with respect to three chronologically related railroad crossing situations that varied in risk level. The situations were described in scenarios and depicted on photographs. The participants were recruited in the suburbs of Paris, at two automated railroad crossings with four half-barriers. We found that the pedestrians had stronger crossing intentions than did car drivers, especially at the more congested crossing of the two under study. For both categories of road users, intentions and the amount of intention variance explained by the extended TPB factors decreased significantly with risk level. In the most dangerous situations, risk-taking was the most unlikely and the least predictable Self-reported past frequency of crossing against safety warning devices was the main predictor of the intention to commit this violation again, especially among males, followed by the attitude and the injunctive norm in favor the violation. Moreover, car drivers were influenced in their crossing intentions by the descriptive norm. The presence of another vehicle on the tracks when the safety warning devices were activated was perceived not as facilitating, but as an additional risk factor. The discussion addresses the importance of taking into account these determinants of violations in conceiving countermeasures. Our findings could be especially useful for conceiving risk-communication campaigns. Copyright © 2016 Elsevier Ltd. All rights reserved.
Complex Network Theory Applied to the Growth of Kuala Lumpur's Public Urban Rail Transit Network.
Directory of Open Access Journals (Sweden)
Rui Ding
Full Text Available Recently, the number of studies involving complex network applications in transportation has increased steadily as scholars from various fields analyze traffic networks. Nonetheless, research on rail network growth is relatively rare. This research examines the evolution of the Public Urban Rail Transit Networks of Kuala Lumpur (PURTNoKL based on complex network theory and covers both the topological structure of the rail system and future trends in network growth. In addition, network performance when facing different attack strategies is also assessed. Three topological network characteristics are considered: connections, clustering and centrality. In PURTNoKL, we found that the total number of nodes and edges exhibit a linear relationship and that the average degree stays within the interval [2.0488, 2.6774] with heavy-tailed distributions. The evolutionary process shows that the cumulative probability distribution (CPD of degree and the average shortest path length show good fit with exponential distribution and normal distribution, respectively. Moreover, PURTNoKL exhibits clear cluster characteristics; most of the nodes have a 2-core value, and the CPDs of the centrality's closeness and betweenness follow a normal distribution function and an exponential distribution, respectively. Finally, we discuss four different types of network growth styles and the line extension process, which reveal that the rail network's growth is likely based on the nodes with the biggest lengths of the shortest path and that network protection should emphasize those nodes with the largest degrees and the highest betweenness values. This research may enhance the networkability of the rail system and better shape the future growth of public rail networks.
Complex Network Theory Applied to the Growth of Kuala Lumpur's Public Urban Rail Transit Network.
Ding, Rui; Ujang, Norsidah; Hamid, Hussain Bin; Wu, Jianjun
2015-01-01
Recently, the number of studies involving complex network applications in transportation has increased steadily as scholars from various fields analyze traffic networks. Nonetheless, research on rail network growth is relatively rare. This research examines the evolution of the Public Urban Rail Transit Networks of Kuala Lumpur (PURTNoKL) based on complex network theory and covers both the topological structure of the rail system and future trends in network growth. In addition, network performance when facing different attack strategies is also assessed. Three topological network characteristics are considered: connections, clustering and centrality. In PURTNoKL, we found that the total number of nodes and edges exhibit a linear relationship and that the average degree stays within the interval [2.0488, 2.6774] with heavy-tailed distributions. The evolutionary process shows that the cumulative probability distribution (CPD) of degree and the average shortest path length show good fit with exponential distribution and normal distribution, respectively. Moreover, PURTNoKL exhibits clear cluster characteristics; most of the nodes have a 2-core value, and the CPDs of the centrality's closeness and betweenness follow a normal distribution function and an exponential distribution, respectively. Finally, we discuss four different types of network growth styles and the line extension process, which reveal that the rail network's growth is likely based on the nodes with the biggest lengths of the shortest path and that network protection should emphasize those nodes with the largest degrees and the highest betweenness values. This research may enhance the networkability of the rail system and better shape the future growth of public rail networks.
Applying the theory of planned behavior to predict dairy product consumption by older adults.
Kim, Kyungwon; Reicks, Marla; Sjoberg, Sara
2003-01-01
The purpose of this study was to explain intention to consume dairy products and consumption of dairy products by older adults using the Theory of Planned Behavior (TPB). The factors examined were attitudes, subjective norms, and perceived behavioral control. A cross-sectional questionnaire was administered. Community centers with congregate dining programs, group classes, and recreational events for older adults. One hundred and sixty-two older adults (mean age 75 years) completed the questionnaire. Subjects were mostly women (76%) and white (65%), with about half having less than a high school education or completing high school. Variables based on the TPB were assessed through questionnaire items that were constructed to form scales measuring attitudes, subjective norms, perceived behavioral control, and intention to consume dairy products. Dairy product consumption was measured using a food frequency questionnaire. Regression analyses were used to determine the association between the scales for the 3 variables proposed in the TPB and intention to consume and consumption of dairy products; the alpha level was set at.05 to determine the statistical significance of results. Attitudes toward eating dairy products and perceived behavioral control contributed to the model for predicting intention, whereas subjective norms did not. Attitudes toward eating dairy products were slightly more important than perceived behavioral control in predicting intention. In turn, intention was strongly related to dairy product consumption, and perceived behavioral control was independently associated with dairy product consumption. These results suggest the utility of the TPB in explaining dairy product consumption for older adults. Nutrition education should focus on improving attitudes and removing barriers to consumption of dairy products for older adults.
Symmetry breaking bifurcations of a current sheet
International Nuclear Information System (INIS)
Parker, R.D.; Dewar, R.L.; Johnson, J.L.
1988-08-01
Using a time evolution code with periodic boundary conditions, the viscoresistive hydromagnetic equations describing an initially static, planar current sheet with large Lundquist number have been evolved for times long enough to reach a steady state. A cosh 2 x resistivity model was used. For long periodicity lengths, L p , the resistivity gradient drives flows which cause forced reconnection at X point current sheets. Using L p as a bifurcation parameter, two new symmetry breaking bifurcations were found - a transition to an asymmetric island chain with nonzero, positive or negative phase velocity, and a transition to a static state with alternating large and small islands. These states are reached after a complex transient behavior which involves a competition between secondary current sheet instability and coalescence. 31 refs., 6 figs
Energy Technology Data Exchange (ETDEWEB)
Degroote, M. [Rice Univ., Houston, TX (United States); Henderson, T. M. [Rice Univ., Houston, TX (United States); Zhao, J. [Rice Univ., Houston, TX (United States); Dukelsky, J. [Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Estructura de la Materia; Scuseria, G. E. [Rice Univ., Houston, TX (United States)
2018-01-03
We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wavefunction. In between, we interpolate using a single parameter. The e ective Hamiltonian is non-hermitian and this Polynomial Similarity Transformation Theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero. Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction stengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.
Applying policy network theory to policy-making in China: the case of urban health insurance reform.
Zheng, Haitao; de Jong, Martin; Koppenjan, Joop
2010-01-01
In this article, we explore whether policy network theory can be applied in the People's Republic of China (PRC). We carried out a literature review of how this approach has already been dealt with in the Chinese policy sciences thus far. We then present the key concepts and research approach in policy networks theory in the Western literature and try these on a Chinese case to see the fit. We follow this with a description and analysis of the policy-making process regarding the health insurance reform in China from 1998 until the present. Based on this case study, we argue that this body of theory is useful to describe and explain policy-making processes in the Chinese context. However, limitations in the generic model appear in capturing the fundamentally different political and administrative systems, crucially different cultural values in the applicability of some research methods common in Western countries. Finally, we address which political and cultural aspects turn out to be different in the PRC and how they affect methodological and practical problems that PRC researchers will encounter when studying decision-making processes.
Chen, J. P.; Yang, J. D.; Guo, W. C.
2016-11-01
A nonlinear mathematical model of hydraulic turbine regulating system is applied to describe hydropower stations with upstream and downstream surge chambers. This model features saturation nonlinearity including pipeline system and turbine regulating system used in stability analysis. First, the existence conditions and direction of Hopf bifurcation are obtained. Second, based on the algebraic criteria for the occurrence of Hopf bifurcation, the stability domain is drawn in a coordinate system, where the proportional gain Kp is the abscissa and the integral gain Ki is the ordinate. Third, the nonlinear dynamic behaviour of a regulating system with different state parameters are analyzed, and the variations of the system stability around the two sides of the bifurcation point are numerically calculated. Based on this work we conclude that the Hopf bifurcation of system is supercritical. The bifurcation parameters that are far from the bifurcation point would be advantageous to the rapid system regulation needed to sustain equilibrium. Furthermore, it is established that using a PID controller is more conducive to stability than a PI controller. The unit stability regulation gets worse by taking into account the saturation nonlinearity.
Stark, Michael; Hennessy, Joseph F. (Technical Monitor)
2002-01-01
My assertion is that not only are product lines a relevant research topic, but that the tools used by empirical software engineering researchers can address observed practical problems. Our experience at NASA has been there are often externally proposed solutions available, but that we have had difficulties applying them in our particular context. We have also focused on return on investment issues when evaluating product lines, and while these are important, one can not attain objective data on success or failure until several applications from a product family have been deployed. The use of the Quality Improvement Paradigm (QIP) can address these issues: (1) Planning an adoption path from an organization's current state to a product line approach; (2) Constructing a development process to fit the organization's adoption path; (3) Evaluation of product line development processes as the project is being developed. The QIP consists of the following six steps: (1) Characterize the project and its environment; (2) Set quantifiable goals for successful project performance; (3) Choose the appropriate process models, supporting methods, and tools for the project; (4) Execute the process, analyze interim results, and provide real-time feedback for corrective action; (5) Analyze the results of completed projects and recommend improvements; and (6) Package the lessons learned as updated and refined process models. A figure shows the QIP in detail. The iterative nature of the QIP supports an incremental development approach to product lines, and the project learning and feedback provide the necessary early evaluations.
Managing common resources in local and global systems. Applying theory across scales
Energy Technology Data Exchange (ETDEWEB)
Karlsson, Sylvia [ed.
1997-12-31
The main point brought forward in this publication is the productiveness of applying theoretical elements, developed within common property resource (CPR) literature, to a broader field of cases on different scales. The common framework for the contributions is a series of seminars held at the Department of Water and Environmental Studies in the spring of 1996, covering expanding work during the last decade on common property resource (CPR) management. It is obvious that there were a broad range of definitions of the concept CPR in the literature. The common pool/property resource concepts are both used, often depending on the resource studied, and authors in this volume have used both terms accordingly. Certain points are raised from empirical cases presented in this volume that are partly missing or not thoroughly stressed in other work in the area of CPR management and which crystallized much clearer when contrasting the situation for cases from different scales. Separate abstracts have been performed for five of the seven contributions
Sex differences in intracranial arterial bifurcations
DEFF Research Database (Denmark)
Lindekleiv, Haakon M; Valen-Sendstad, Kristian; Morgan, Michael K
2010-01-01
Subarachnoid hemorrhage (SAH) is a serious condition, occurring more frequently in females than in males. SAH is mainly caused by rupture of an intracranial aneurysm, which is formed by localized dilation of the intracranial arterial vessel wall, usually at the apex of the arterial bifurcation. T....... The female preponderance is usually explained by systemic factors (hormonal influences and intrinsic wall weakness); however, the uneven sex distribution of intracranial aneurysms suggests a possible physiologic factor-a local sex difference in the intracranial arteries....
Bifurcation and complex dynamics of a discrete-time predator-prey system
Directory of Open Access Journals (Sweden)
S. M. Sohel Rana
2015-06-01
Full Text Available In this paper, we investigate the dynamics of a discrete-time predator-prey system of Holling-I type in the closed first quadrant R+2. The existence and local stability of positive fixed point of the discrete dynamical system is analyzed algebraically. It is shown that the system undergoes a flip bifurcation and a Neimark-Sacker bifurcation in the interior of R+2 by using bifurcation theory. It has been found that the dynamical behavior of the model is very sensitive to the parameter values and the initial conditions. Numerical simulation results not only show the consistence with the theoretical analysis but also display the new and interesting dynamic behaviors, including phase portraits, period-9, 10, 20-orbits, attracting invariant circle, cascade of period-doubling bifurcation from period-20 leading to chaos, quasi-periodic orbits, and sudden disappearance of the chaotic dynamics and attracting chaotic set. In particular, we observe that when the prey is in chaotic dynamic, the predator can tend to extinction or to a stable equilibrium. The Lyapunov exponents are numerically computed to characterize the complexity of the dynamical behaviors. The analysis and results in this paper are interesting in mathematics and biology.
Directory of Open Access Journals (Sweden)
Krystel K. Castillo-Villar
2014-11-01
Full Text Available Bioenergy is a new source of energy that accounts for a substantial portion of the renewable energy production in many countries. The production of bioenergy is expected to increase due to its unique advantages, such as no harmful emissions and abundance. Supply-related problems are the main obstacles precluding the increase of use of biomass (which is bulky and has low energy density to produce bioenergy. To overcome this challenge, large-scale optimization models are needed to be solved to enable decision makers to plan, design, and manage bioenergy supply chains. Therefore, the use of effective optimization approaches is of great importance. The traditional mathematical methods (such as linear, integer, and mixed-integer programming frequently fail to find optimal solutions for non-convex and/or large-scale models whereas metaheuristics are efficient approaches for finding near-optimal solutions that use less computational resources. This paper presents a comprehensive review by studying and analyzing the application of metaheuristics to solve bioenergy supply chain models as well as the exclusive challenges of the mathematical problems applied in the bioenergy supply chain field. The reviewed metaheuristics include: (1 population approaches, such as ant colony optimization (ACO, the genetic algorithm (GA, particle swarm optimization (PSO, and bee colony algorithm (BCA; and (2 trajectory approaches, such as the tabu search (TS and simulated annealing (SA. Based on the outcomes of this literature review, the integrated design and planning of bioenergy supply chains problem has been solved primarily by implementing the GA. The production process optimization was addressed primarily by using both the GA and PSO. The supply chain network design problem was treated by utilizing the GA and ACO. The truck and task scheduling problem was solved using the SA and the TS, where the trajectory-based methods proved to outperform the population
DATE analysis: A general theory of biological change applied to microarray data.
Rasnick, David
2009-01-01
In contrast to conventional data mining, which searches for specific subsets of genes (extensive variables) to correlate with specific phenotypes, DATE analysis correlates intensive state variables calculated from the same datasets. At the heart of DATE analysis are two biological equations of state not dependent on genetic pathways. This result distinguishes DATE analysis from other bioinformatics approaches. The dimensionless state variable F quantifies the relative overall cellular activity of test cells compared to well-chosen reference cells. The variable pi(i) is the fold-change in the expression of the ith gene of test cells relative to reference. It is the fraction phi of the genome undergoing differential expression-not the magnitude pi-that controls biological change. The state variable phi is equivalent to the control strength of metabolic control analysis. For tractability, DATE analysis assumes a linear system of enzyme-connected networks and exploits the small average contribution of each cellular component. This approach was validated by reproducible values of the state variables F, RNA index, and phi calculated from random subsets of transcript microarray data. Using published microarray data, F, RNA index, and phi were correlated with: (1) the blood-feeding cycle of the malaria parasite, (2) embryonic development of the fruit fly, (3) temperature adaptation of Killifish, (4) exponential growth of cultured S. pneumoniae, and (5) human cancers. DATE analysis was applied to aCGH data from the great apes. A good example of the power of DATE analysis is its application to genomically unstable cancers, which have been refractory to data mining strategies. 2009 American Institute of Chemical Engineers Biotechnol.
Dynamical pattern formation in two-dimensional fluids and Landau pole bifurcation
Ogawa, Shun; Barré, Julien; Morita, Hidetoshi; Yamaguchi, Yoshiyuki Y.
2014-06-01
A phenomenological theory is proposed to analyze the asymptotic dynamics of perturbed inviscid Kolmogorov shear flows in two dimensions. The phase diagram provided by the theory is in qualitative agreement with numerical observations, which include three phases depending on the aspect ratio of the domain and the size of the perturbation: a steady shear flow, a stationary dipole, and four traveling vortices. The theory is based on a precise study of the inviscid damping of the linearized equation and on an analysis of nonlinear effects. In particular, we show that the dominant Landau pole controlling the inviscid damping undergoes a bifurcation, which has important consequences on the asymptotic fate of the perturbation.
Stochastic dynamics in a two-dimensional oscillator near a saddle-node bifurcation
Inchiosa, M. E.; in, V.; Bulsara, A. R.; Wiesenfeld, K.; Heath, T.; Choi, M. H.
2001-06-01
We study the oscillator equations describing a particular class of nonlinear amplifier, exemplified in this work by a two-junction superconducting quantum interference device. This class of dynamic system is described by a potential energy function that can admit minima (corresponding to stable solutions of the dynamic equations), or ``running states'' wherein the system is biased so that the potential minima disappear and the solutions display spontaneous oscillations. Just beyond the onset of the spontaneous oscillations, the system is known to show significantly enhanced sensitivity to very weak magnetic signals. The global phase space structure allows us to apply a center manifold technique to approximate analytically the oscillatory behavior just past the (saddle-node) bifurcation and compute the oscillation period, which obeys standard scaling laws. In this regime, the dynamics can be represented by an ``integrate-fire'' model drawn from the computational neuroscience repertoire; in fact, we obtain an ``interspike interval'' probability density function and an associated power spectral density (computed via Renewal theory) that agree very well with the results obtained via numerical simulations. Notably, driving the system with one or more time sinusoids produces a noise-lowering injection locking effect and/or heterodyning.
Bifurcation analysis for a tri-neuron discrete-time BAM neural network with delays
International Nuclear Information System (INIS)
Gan Qintao; Xu Rui; Hu Wenhua; Yang Pinghua
2009-01-01
In this paper, a tri-neuron discrete-time BAM neural network with delays is investigated. By analyzing the corresponding characteristic equations, the local asymptotic stability of the null solution and the existence of Neimark-Sacker bifurcations are discussed. By using the normal form theory and center manifold reduction, we derive explicit formulae to determine the stability and direction. Numerical simulations are carried out to illustrate the main results.
Raskin, Daniel; Khaitovich, Boris; Balan, Shmuel; Silverberg, Daniel; Halak, Moshe; Rimon, Uri
2018-01-01
To assess the technical success of the Outback reentry device in contralateral versus ipsilateral approaches for femoropopliteal arterial occlusion. A retrospective review of patients treated for critical limb ischemia (CLI) using the Outback between January 2013 and July 2016 was performed. Age, gender, length and site of the occlusion, approach site, aortic bifurcation angle, and reentry site were recorded. Calcification score was assigned at both aortic bifurcation and reentry site. Technical success was assessed. During the study period, a total of 1300 endovascular procedures were performed on 489 patients for CLI. The Outback was applied on 50 femoropopliteal chronic total occlusions. Thirty-nine contralateral and 11 ipsilateral antegrade femoral were accessed. The device was used successfully in 41 patients (82%). There were nine failures, all in the contralateral approach group. Six due to inability to deliver the device due to acute aortic bifurcation angle and three due to failure to achieve luminal reentry. Procedural success was significantly affected by the aortic bifurcation angle (p = 0.013). The Outback has high technical success rates in treatment of femoropopliteal occlusion, when applied from either an ipsi- or contralateral approach. When applied in contralateral access, acute aortic bifurcation angle predicts procedural failure.
Hybrid Control of Hopf Bifurcation for an Internet Congestion Model
Cheng, Zunshui; Qiu, Jianlong; Wang, Guangbin; Yu, Bin
In this paper, the problem of Hopf bifurcation control for an Internet congestion model with time delays is considered by using a new hybrid control strategy, in which state feedback and parameter perturbation are used. It is well known that for the system without control, as the positive gain parameter of the system passes a critical point, Hopf bifurcation occurs. To control the Hopf bifurcation, a hybrid control strategy is proposed and the onset of an inherent bifurcation is delayed (advanced) when such bifurcation is undesired (desired). Furthermore, the dynamic behaviors of the controlled system can also be changed by choosing appropriate control parameters. Numerical simulation results confirm that the new control strategy is efficient in controlling Hopf bifurcation.