The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Todd M. Tinsley - One of the best experts on this subject based on the ideXlab platform.
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Time Development of a quasistationary state
Physical Review A, 2002Co-Authors: Duane A. Dicus, Wayne W. Repko, R. F. Schwitters, Todd M. TinsleyAbstract:Approximately forty years ago it was realized that the Time Development of decaying systems might not be precisely exponential. Rolf Winter (Phys. Rev. {\bf 123}, 1503 (1961)) analyzed the simplest nontrivial system - a particle tunneling out of a well formed by a wall and a delta-function. He calculated the probability current just outside the well and found irregular oscillations on a short Time scale followed by an exponential decrease followed by more oscillations and finally by a decrease as a power of the Time. We have reanalyzed this system, concentrating on the survival probability of the particle in the well rather than the probability current, and find a different short Time behavior.Comment: 8 pages, 6 figures, RevTex
Ian Gardner Bearden - One of the best experts on this subject based on the ideXlab platform.
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Time Development in the Early History of Social Networks: Link Stabilization, Group Dynamics, and Segregation
PloS one, 2014Co-Authors: Jesper Bruun, Ian Gardner BeardenAbstract:Studies of the Time Development of empirical networks usually investigate late stages where lasting connections have already stabilized. Empirical data on early network history are rare but needed for a better understanding of how social network topology develops in real life. Studying students who are beginning their studies at a university with no or few prior connections to each other offers a unique opportunity to investigate the formation and early Development of link patterns and community structure in social networks. During a nine week introductory physics course, first year physics students were asked to identify those with whom they communicated about problem solving in physics during the preceding week. We use these students' self reports to produce Time dependent student interaction networks. We investigate these networks to elucidate possible effects of different student attributes in early network formation. Changes in the weekly number of links show that while roughly half of all links change from week to week, students also reestablish a growing number of links as they progress through their first weeks of study. Using the Infomap community detection algorithm, we show that the networks exhibit community structure, and we use non-network student attributes, such as gender and end-of-course grade to characterize communities during their formation. Specifically, we develop a segregation measure and show that students structure themselves according to gender and pre-organized sections (in which students engage in problem solving and laboratory work), but not according to end-of-coure grade. Alluvial diagrams of consecutive weeks' communities show that while student movement between groups are erratic in the beginning of their studies, they stabilize somewhat towards the end of the course. Taken together, the analyses imply that student interaction networks stabilize quickly and that students establish collaborations based on who is immediately available to them and on observable personal characteristics.
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Time Development of Early Social Networks: Link analysis and group dynamics.
arXiv: Physics and Society, 2013Co-Authors: Jesper Bruun, Ian Gardner BeardenAbstract:Empirical data on early network history are rare. Students beginning their studies at a university with no or few prior connections to each other offer a unique opportunity to investigate the formation and early Development of social networks. During a nine week introductory physics course, first year physics students were asked to identify those with whom they communicated about problem solving in physics during the preceding week. We use these students' self reports to produce Time dependent student interaction networks. These networks have also been investigated to elucidate possible effects of gender and students' final course grade. Changes in the weekly number of links are investigated to show that while roughly half of all links change from week to week, students also reestablish a growing number of links as they progress through their first weeks of study. To investigate how students group, Infomap is used to establish groups. Further, student group flow is examined using alluvial diagrams, showing that many students jump between group each week., Finally, a segregation measure is developed which shows that students structure themselves according to gender and laboratory exercise groups and not according to end-of-course grade. The results show the behavior of an early social-educational network, and may have implications for theoretical network models as well as for physics education.
Shuho Tatsuno - One of the best experts on this subject based on the ideXlab platform.
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Time Development of a persistent hole burning in multiple-scattering media.
Physical Review E, 2004Co-Authors: Makoto Tomita, Kentarou Ono, Shuho TatsunoAbstract:We investigated the Time Development of persistent hole burning in photoreactive and multiple-scattering media. In this hole burning, a writing laser beam recodes the volume speckle pattern inside the medium through the photoreactive process, and then the luminescence intensity excited by a reading beam is measured as a function of the frequency or wave vector difference between the writing and reading beams. The Time Development reflects the statistics of the intensity fluctuations in the speckle inside the medium. One of the striking results is that the maximum hole depth is $\ensuremath{\sim}0.26$. We distinguish three types of samples according to the geometric configurations and the photoreactive processes and discuss the hole shape, hole width, and the depth during Time Development. Hole burning experiments were also performed using a spiropyran derivative photochromic dye. The experimental results showed good agreement with the theory.
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Time Development of a persistent hole burning in multiple-scattering media.
Physical review. E Statistical nonlinear and soft matter physics, 2004Co-Authors: Makoto Tomita, Kentarou Ono, Shuho TatsunoAbstract:We investigated the Time Development of persistent hole burning in photoreactive and multiple-scattering media. In this hole burning, a writing laser beam recodes the volume speckle pattern inside the medium through the photoreactive process, and then the luminescence intensity excited by a reading beam is measured as a function of the frequency or wave vector difference between the writing and reading beams. The Time Development reflects the statistics of the intensity fluctuations in the speckle inside the medium. One of the striking results is that the maximum hole depth is approximately 0.26 . We distinguish three types of samples according to the geometric configurations and the photoreactive processes and discuss the hole shape, hole width, and the depth during Time Development. Hole burning experiments were also performed using a spiropyran derivative photochromic dye. The experimental results showed good agreement with the theory.
Alain Molinari - One of the best experts on this subject based on the ideXlab platform.
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The Time Development of eulerian/lagrangian perturbations to simple shear and its applications to shear banding
Journal of the Mechanics and Physics of Solids, 1992Co-Authors: Claude Fressengeas, Alain MolinariAbstract:Abstract T he Time Development of two-dimensional linear disturbances to the simple shear deformation of viscoplastic hardening/softening solids and its consequences on the localization of the plastic flow into shear bands are investigated. Attention is focused on the orientation features of shear banding. A local analysis is carried out on the basis of a generalized Orr-Sommerfeld equation ; the classic Time-independent characteristic lines theory is embedded in a Time-dependent analysis. It is shown that the characteristic directions are not equivalent when the Time evolution is considered, owing to the convective nature of the shear banding instability. The transition between a Time-independent behavior for which a pair of shear bands occurs abruptly along the characteristic directions, and a Time-dependent regime where a single shear band goes to completion in the shearing direction is discussed.
Sylwia Wiatr - One of the best experts on this subject based on the ideXlab platform.
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Estimation of simple and complex response Time Development using regression analysis
Polish Journal of Sport and Tourism, 2013Co-Authors: Janusz Jaworski, Eligiusz Madejski, Grażyna Kosiba, Sylwia WiatrAbstract:Introduction. The aim of the study was to determine the age, level of achieving maximum results and growth of reaction Time dynamics. Materials and methods. The study included 567 males of age between 7 and 22 years. Study materials included the results of simple reaction Time and complex reaction Time during progressive period. Conclusions. Progressive period of results' Development lasts until the age of about 17-17.5, then stabilization of the analyzed results was observe. The most dynamic growth of all types of reaction Time was observed in the analyzed 7 and 8-year-old boys.
