Results for 'time‐dependent variables'

998 found
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  1.  43
    A Light-Fronts Approach to a Two-Center Time-Dependent Dirac Equation.Bilha Segev & J. C. Wells - 2001 - Foundations of Physics 31 (6):993-1015.
    The two center time dependent Dirac equation, for an electron in the external field of two colliding ultrarelativistic heavy ions is considered. In the ultrarelativistic limit, the ions are practically moving at the speed of light and the electromagnetic fields of the ions are confined to the light fronts by the extreme Lorentz contraction and by the choice of gauge, designed to remove the long-range Coulomb effects. An exact solution to the ultrarelativistic limit of the two-center Dirac equation is found (...)
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  2.  38
    Complex-Domain Semiclassical Theory: Application to Time-Dependent Barrier Tunneling Problems. [REVIEW]Kin'ya Takahashi & Kensuke S. Ikeda - 2001 - Foundations of Physics 31 (1):177-201.
    Semiclassical theory based upon complexified classical mechanics is developed for periodically time-dependent scattering systems, which are minimal models of multi-dimensional systems. Semiclassical expression of the wave-matrix is derived, which is represented as the sum of the contributions from classical trajectories, where all the dynamical variables as well as the time are extended to the complex-domain. The semiclassical expression is examined by a periodically perturbed 1D barrier system and an excellent agreement with the fully quantum result is confirmed. In a (...)
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  3.  13
    Analysing Cross-Sectional Data with Time-Dependent Covariates: The Case of Age at First Birth in South Africa.Acheampong Yaw Amoateng, I. Kalule-Sabiti & Prudence Ditlopo - 2003 - Journal of Biosocial Science 35 (3):353-367.
    Analysing time-dependent independent variables requires the use of process-oriented statistical models. Yet social scientists have often had to use data collected at a single point in time, making their task difficult. Making several assumptions about the covariates, the present study uses survival analysis and other statistical techniques to analyse the 1996 South African population census data and examine the effects of selected independent variables on the timing of parenthood in the country. It was found that the onset of (...)
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  4.  20
    Variables Aggregation in Time Varying Discrete Systems.Luis Sanz & Rafael Bravo de la Parra - 1998 - Acta Biotheoretica 46 (3):273-297.
    In this work we extend approximate aggregation methods in time discrete linear models to the case of time varying environments. Approximate aggregation consists in describing some features of the dynamics of a general system involving many coupled variables in terms of the dynamics of a reduced system with a few number of variables. We present a time discrete time varying model in which we distinguish two time scales. By using perturbation methods we transform the system to make the (...)
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  5.  18
    Predictive Survival Model with Time‐Dependent Prognostic Factors: Development of Computer‐Aided SAS Macro Program.Li‐Sheng Chen, Ming‐Fang Yen, Hui‐Min Wu, Chao‐Sheng Liao, Der‐Ming Liou, Hsu‐Sung Kuo & Tony Hsiu‐Hsi Chen - 2005 - Journal of Evaluation in Clinical Practice 11 (2):181-193.
  6.  19
    Addition of Time‐Dependent Covariates to a Survival Model Significantly Improved Predictions for Daily Risk of Hospital Death.Jenna Wong, Monica Taljaard, Alan J. Forster, Gabriel J. Escobar & Carl van Walraven - 2013 - Journal of Evaluation in Clinical Practice 19 (2):351-357.
  7.  80
    Hidden Variables with Nonlocal Time.Hrvoje Nikolić - 2012 - Foundations of Physics 42 (5):632-646.
    To relax the apparent tension between nonlocal hidden variables and relativity, we propose that the observable proper time is not the same quantity as the usual proper-time parameter appearing in local relativistic equations. Instead, the two proper times are related by a nonlocal rescaling parameter proportional to |ψ|2, so that they coincide in the classical limit. In this way particle trajectories may obey local relativistic equations of motion in a manner consistent with the appearance of nonlocal quantum correlations. To (...)
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  8. Homotopy and Path Integrals in the Time Dependent Aharonov-Bohm Effect.Bernar Gaveau, Antigone M. Nounou & Lawrence S. Schulman - 2011 - Foundations of Physics 41 (9):1462-1474.
    For time-independent fields the Aharonov-Bohm effect has been obtained by idealizing the coordinate space as multiply-connected and using representations of its fundamental homotopy group to provide information on what is physically identified as the magnetic flux. With a time-dependent field, multiple-connectedness introduces the same degree of ambiguity; by taking into account electromagnetic fields induced by the time dependence, full physical behavior is again recovered once a representation is selected. The selection depends on a single arbitrary time (hence the so-called holonomies (...)
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  9.  19
    Quantifying the Impact of Survivor Treatment Bias in Observational Studies.Peter C. Austin, Muhammad M. Mamdani, Carl Van Walraven & Jack V. Tu - 2006 - Journal of Evaluation in Clinical Practice 12 (6):601-612.
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  10. A Parallel Distributed Processing Model of Unconscious Priming.Scott Drury - manuscript
     
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  11.  45
    Schrödinger’s Equation with Gauge Coupling Derived From a Continuity Equation.U. Klein - 2009 - Foundations of Physics 39 (8):964-995.
    A quantization procedure without Hamiltonian is reported which starts from a statistical ensemble of particles of mass m and an associated continuity equation. The basic variables of this theory are a probability density ρ, and a scalar field S which defines a probability current j=ρ ∇ S/m. A first equation for ρ and S is given by the continuity equation. We further assume that this system may be described by a linear differential equation for a complex-valued state variable χ. (...)
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  12.  65
    On the Derivation of the Time-Dependent Equation of Schrödinger.John S. Briggs & Jan M. Rost - 2001 - Foundations of Physics 31 (4):693-712.
    Few have done more than Martin Gutzwiller to clarify the connection between classical time-dependent motion and the time-independent states of quantum systems. Hence it seems appropriate to include the following discussion of the origins of the time-dependent Schrödinger equation in this volume dedicated to him.
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  13.  34
    WKB Properties of the Time-Dependent Schrödinger System.L. O'Raifeartaigh & Andreas Wipf - 1988 - Foundations of Physics 18 (3):307-329.
    It is shown that the time-dependent WKB expansion highlights some of the hidden properties of the Schrödinger equation and forms a natural bridge between that equation and the functional integral formulation of quantum mechanics. In particular it is shown that the leading (zero- and first-order in ħ) terms in the WKB expansion are essentially classical, and the relationship of this result to the classical nature of the WKB partition function, and of the anomalies in quantum field theory, is discussed.
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  14.  27
    Time Dependent Propositions and Quantum Logic.Peter Mittelstaedt - 1977 - Journal of Philosophical Logic 6 (1):463 - 472.
    Compound propositions which can successfully be defended in a quantumdialogue independent of the elementary propositions contained in it, must have this property also independent of the mutual elementary commensur-abilities. On the other hand, formal commensurabilities must be taken into account. Therefore, for propositions which can be proved by P, irrespective of both the elementary propositions and of the elementary commensur-abilities, there exists a formal strategy of success. The totality of propositions with a formal strategy of success in a quantum dialogue (...)
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  15.  33
    Exact Quantum-Statistical Dynamics of Time-Dependent Generalized Oscillators.Don Page - manuscript
    Using linear invariant operators in a constructive way we find the most general thermal density operator and Wigner function for time-dependent generalized oscillators. The general Wigner function has five free parameters and describes the thermal Wigner function about a classical trajectory in phase space. The contour of the Wigner function depicts an elliptical orbit with a constant area moving about the classical trajectory, whose eccentricity determines the squeezing of the initial vacuum.
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  16. Time-Dependent Quantum Weak Values: Decay Law for Post-Selected States.P. C. W. Davies - unknown
    Weak measurements offer new insights into the behavior of quantum systems. Combined with post-selection, quantum mechanics predicts a range of new experimentally testable phenomena. In this paper I consider weak measurements performed on time-dependent pre- and post-selected ensembles, with emphasis on the decay of excited states. The results show that the standard exponential decay law is a limiting case of a more general law that depends on both the time of post-selection and the choice of final state. The generalized law (...)
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  17.  22
    Torsion Fields, Cartan–Weyl Space–Time and State-Space Quantum Geometries, Their Brownian Motions, and the Time Variables.Diego L. Rapoport - 2007 - Foundations of Physics 37 (4-5):813-854.
    We review the relation between spacetime geometries with trace-torsion fields, the so-called Riemann–Cartan–Weyl (RCW) geometries, and their associated Brownian motions. In this setting, the drift vector field is the metric conjugate of the trace-torsion one-form, and the laplacian defined by the RCW connection is the differential generator of the Brownian motions. We extend this to the state-space of non-relativistic quantum mechanics and discuss the relation between a non-canonical quantum RCW geometry in state-space associated with the gradient of the quantum-mechanical expectation (...)
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  18.  8
    Information Encoding and Decision Time as Variables in Human Choice Behavior.Louis M. Herman - 1966 - Journal of Experimental Psychology 71 (5):718.
  19. “Forget Time”.Carlo Rovelli - 2011 - Foundations of Physics 41 (9):1475-1490.
    Following a line of research that I have developed for several years, I argue that the best strategy for understanding quantum gravity is to build a picture of the physical world where the notion of time plays no role at all. I summarize here this point of view, explaining why I think that in a fundamental description of nature we must “forget time”, and how this can be done in the classical and in the quantum theory. The idea is to (...)
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  20.  36
    Coordinates with Non-Singular Curvature for a Time Dependent Black Hole Horizon.James Lindesay - 2007 - Foundations of Physics 37 (8):1181-1196.
    A naive introduction of a dependency of the mass of a black hole on the Schwarzschild time coordinate results in singular behavior of curvature invariants at the horizon, violating expectations from complementarity. If instead a temporal dependence is introduced in terms of a coordinate akin to the river time representation, the Ricci scalar is nowhere singular away from the origin. It is found that for a shrinking mass scale due to evaporation, the null radial geodesics that generate the horizon are (...)
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  21.  20
    Are There Causal Relations Among Dependent Variables?Daniel Hausman - 1983 - Philosophy of Science 50 (1):58-81.
    This paper makes explicit and takes issue with the bizarre view, which is unfortunately prevalent among social scientists, that causal relations are features of models only. There are some good reasons to represent causal factors with independent variables. But the association between causes and independent variables is only a desideratum in model construction. It is not a criterion for judging which things are causes and which are effects.
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  22. A Polynomial Time Algorithm for Determining Dag Equivalence in the Presence of Latent Variables and Selection Bias.Peter Spirtes - unknown
    if and only if for every W in V, W is independent of the set of all its non-descendants conditional on the set of its parents. One natural question that arises with respect to DAGs is when two DAGs are “statistically equivalent”. One interesting sense of “statistical equivalence” is “d-separation equivalence” (explained in more detail below.) In the case of DAGs, d-separation equivalence is also corresponds to a variety of other natural senses of statistical equivalence (such as representing the same (...)
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  23.  2
    A Time-Dependent Fuzzy Programming Approach for the Green Multimodal Routing Problem with Rail Service Capacity Uncertainty and Road Traffic Congestion.Yan Sun, Martin Hrušovský, Chen Zhang & Maoxiang Lang - 2018 - Complexity 2018:1-22.
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  24.  11
    Differential Time-Dependent Effects of Emotion on Recollective Experience and Memory for Contextual Information.Tali Sharot & Andrew P. Yonelinas - 2008 - Cognition 106 (1):538-547.
  25. Time-Dependent Symmetries: The Link Between Gauge Symmetries and Indeterminism.David Wallace - 2002 - In Katherine Brading & Elena Castellani (eds.), Symmetries in Physics: Philosophical Reflections. Cambridge University Press. pp. 163--173.
    Mathematically, gauge theories are extraordinarily rich --- so rich, in fact, that it can become all too easy to lose track of the connections between results, and become lost in a mass of beautiful theorems and properties: indeterminism, constraints, Noether identities, local and global symmetries, and so on. -/- One purpose of this short article is to provide some sort of a guide through the mathematics, to the conceptual core of what is actually going on. Its focus is on the (...)
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  26.  3
    A Novel Approach to a Time-Dependent-Coefficient WBK System: Doubly Periodic Waves and Singular Nonlinear Dynamics.Bo Xu & Sheng Zhang - 2018 - Complexity 2018:1-14.
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  27.  5
    Time-Dependent Gambling: Odds Now, Money Later.Michael D. Sagristano, Yaacov Trope & Nira Liberman - 2002 - Journal of Experimental Psychology: General 131 (3):364-376.
  28.  6
    Time-Dependent Paths, Fictive Temperatures and Residual Entropy of Glass.G. P. Johari & D. P. B. Aji - 2010 - Philosophical Magazine 90 (33):4377-4392.
  29.  8
    Chaos Synchronization in Time-Dependent Duplex Networks.Qian Liu, Wenchen Han, Lixing Lei, Qionglin Dai & Junzhong Yang - 2019 - Complexity 2019:1-8.
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  30.  17
    Time-Dependent Effects of Acute Exercise on University Students’ Cognitive Performance in Temperate and Cold Environments.Ling-Yu Ji, Xiao-Ling Li, Yang Liu, Xiu-Wen Sun, Hui-Fen Wang, Long Chen & Liang Gao - 2017 - Frontiers in Psychology 8.
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  31.  23
    Strain-Dependent Transition of Time-Dependent Deformation Mechanism in Single-Crystal ZnO Evaluated by Spherical Nanoindentation.Yong-Jae Kim, In-Chul Choi, Jung-A. Lee, Moo-Young Seok & Jae-il Jang - 2015 - Philosophical Magazine 95 (16-18):1896-1906.
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  32.  1
    Time-Dependent Variations in Aversively Motivated Behaviors: Nonassociative Effects of Cholinergic and Catecholaminergic Activity.Hymie Anisman - 1975 - Psychological Review 82 (5):359-385.
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  33.  38
    Solutions of the Time-Dependent Schrödinger Equation for a Two-State System.J. F. Ralph, T. D. Clark, H. Prance, R. J. Prance, A. Widom & Y. N. Srivastava - 1998 - Foundations of Physics 28 (8):1271-1282.
    The statistical properties of a single quantum object and an ensemble of independent such objects are considered in detail for two-level systems. Computer simulations of dynamic zero-point quantum fluctuations for a single quantum object are reported and compared with analytic solutions for the ensemble case.
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  34.  13
    Time-Dependent Neutron Interferometry: Evidence Against Wave Packet Collapse? [REVIEW]C. Dewdney, A. Garuccio, Ph Gueret, A. Kyprianidis & J. P. Vigier - 1985 - Foundations of Physics 15 (10):1031-1042.
    If the energy-absorbing radio-frequency spin-flipping device used in perfect crystal neutron interferometry is an intermediate measuring device, then the experimental results contradict the associated wave packet collapse and support the real existence of the de Broglie pilot waves in both arms while the neutron travels in only one.
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  35.  2
    A Novel Index Method for K Nearest Object Query Over Time-Dependent Road Networks.Yajun Yang, Hanxiao Li, Junhu Wang, Qinghua Hu, Xin Wang & Muxi Leng - 2019 - Complexity 2019:1-18.
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  36.  17
    Time-Dependent and Dose-Dependent Effects of Fenfluramine Upon Pain Thresholds.Richard J. Bodnar, Donald Simone, Dennis D. Kelly, Martin Brutus, Murray Glusman & Richard Meibach - 1982 - Bulletin of the Psychonomic Society 19 (6):355-358.
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  37.  19
    The Influence of Time Course Variables on REM Sleep.H. W. Agnew & W. B. Webb - 1973 - Bulletin of the Psychonomic Society 2 (3):131-133.
  38.  14
    Metacontrast: Internal Contours and Different Dependent Variables.Lester A. Lefton & Linda L. Hernandez - 1977 - Bulletin of the Psychonomic Society 9 (6):427-430.
  39.  11
    Paradoxical Dopaminergic Drug Effects in Extraversion: Dose- and Time-Dependent Effects of Sulpiride on EEG Theta Activity.Mira-Lynn Chavanon, Jan Wacker & Gerhard Stemmler - 2013 - Frontiers in Human Neuroscience 7.
  40.  3
    Human Preferences for Time-Dependent and Response-Dependent Reinforcement Schedules.Robert W. Schaeffer - 1979 - Bulletin of the Psychonomic Society 14 (4):293-296.
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  41.  10
    Comment on ‘Time-Dependent Paths, Fictive Temperatures and Residual Entropy of Glass’.P. K. Gupta & J. C. Mauro - 2011 - Philosophical Magazine 91 (30):3858-3860.
  42.  10
    Rejoinder to the Response to the Comment on ‘Time-Dependent Paths, Fictive Temperatures and Residual Entropy of Glass’.P. K. Gupta & J. C. Mauro - 2011 - Philosophical Magazine 91 (30):3865-3866.
  43.  13
    New Time Dependent Gravity Displays Dark Matter and Dark Energy Effects.Pharis E. Williams - 2008 - Apeiron: Studies in Infinite Nature 15 (3):294.
  44.  8
    Time-Dependent Benioff Strain Release Diagrams.V. Frid, J. Goldbaum, A. Rabinovitch & D. Bahat - 2011 - Philosophical Magazine 91 (12):1693-1704.
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  45.  7
    Time-Dependent Spectra of Electroluminescent ZnS:Cu, Pb.J. Weiszburg, J. Schanda & Z. Bodó - 1959 - Philosophical Magazine 4 (43):830-832.
  46.  6
    Time-Dependent Solutions of Transport Equations.A. M. Guénault & D. K. C. MacDonald - 1963 - Philosophical Magazine 8 (93):1569-1580.
  47.  7
    Reward and Reward Omission: Time-Dependent Aftereffects in Rats and Fish.Stanley R. Scobie, Dennis C. Gold & Daniel Fallon - 1974 - Bulletin of the Psychonomic Society 3 (6):452-454.
  48.  5
    Response to the Comment on ‘Time-Dependent Paths, Fictive Temperatures and Residual Entropy of Glass’.G. P. Johari & D. P. B. Aji - 2011 - Philosophical Magazine 91 (30):3861-3864.
  49.  5
    Implication of a Time-Dependent Model of Sexual Intercourse Within the Menstrual Cycle.J. G. Dobbins - 1980 - Journal of Biosocial Science 12 (2):133.
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  50.  4
    Exact Response Functions Within the Time-Dependent Gutzwiller Approach.J. Bünemann, S. Wasner, E. V. Oelsen & G. Seibold - 2015 - Philosophical Magazine 95 (5-6):550-562.
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