18,669 research outputs found

    The Virtual Runner Learning Game

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    A learning game has been developed which allows learners to study and learn about the significance of three important variables in human physiology (lactate, glycogen, and hydration) and their influence on sports performance during running. The player can control the speed of the runner, and as a consequence the resulting physiological processes are simulated in real-time. The performance degradation of the runner due to these processes requires that different strategies for pacing the running speed are applied by the player, depending on the total length of the run. The game has been positively evaluated in a real learning context of academic physiology teaching

    Accurate polarization within a unified Wannier function formalism

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    We present an alternative formalism for calculating the maximally localized Wannier functions in crystalline solids, obtaining an expression which is extremely simple and general. In particular, our scheme is exactly invariant under Brillouin zone folding, and therefore it extends trivially to the Gamma-point case. We study the convergence properties of the Wannier functions, their quadratic spread and centers as obtained by our simplified technique. We show how this convergence can be drastically improved by a simple and inexpensive ``refinement'' step, which allows for very efficient and accurate calculations of the polarization in zero external field.Comment: 9 pages, 4 figure

    Ab-initio theory of metal-insulator interfaces in a finite electric field

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    We present a novel technique for calculating the dielectric response of metal/insulator heterostructures. This scheme allows, for the first time, the fully first-principles calculation of the microscopic properties of thin-film capacitors at finite bias potential. The method can be readily applied to pure insulators, where it provides an interesting alternative to conventional finite-field techniques based on the Berry-phase formalism. We demonstrate the effectiveness of our method by performing comprehensive numerical tests on a model Ag/MgO/Ag heterostructure.Comment: 10 pages, 5 figures, major revisio

    Orbitofrontal epilepsy: Electroclinical analysis of surgical cases and literature review

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    Clinical and electrographic data were reviewed on 2 of our patients with orbitofrontal epilepsy who were seizure free at 5-year follow-up, and on 2 similar patients from the literature. One of our patients was lesional, and the other was nonlesional. Interictal EEG discharges were lateralized to the side of invasively recorded orbitofrontal seizures in the nonlesional case. In this case, no clinical manifestations occurred until the orbitofrontal discharge had spread to the opposite orbitofrontal and both mesial temporal areas. Unresponsiveness or arrest of activity were the initial manifestations of complex partial seizures in both cases. The 2 cases from the literature with long-term seizure-free follow-up had little impairment of awareness and displayed vigorous motor automatisms. Interictal epileptiform activity was bifrontally synchronous in 1 case. Ipsilateral frontotemporal discharges were seen in both. Invasive ictal epileptiform activity appeared maximal in the ipsilateral orbitofrontal region in both patients. No consistent electrographic or clinical pattern characterized these 4 cases. Seizures of orbitofrontal origin may be characterized by either unresponsiveness associated with oroalimentary automatisms or limited alteration of awareness and associated with vigorous motor automatisms. Invasive monitoring of the orbitofrontal cortex should be considered in nonlesional cases with complex partial seizures that show nonlocalizing ictal patterns and interictal frontal or frontotemporal epileptiform discharges. Copyright (C) 2004 S. Karger AG, Basel

    Motivations and experiences of UK students studying abroad

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    This report summarises the findings of research aimed at improving understanding of the motivations behind the international diploma mobility of UK student

    Responsibility, resilience and symbolic power

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    The reciprocal nature of the relationship between the concepts of responsibilisation and resilience appears, in policy and political circles at least, almost natural. Whilst both concepts have been subjected to sustained academic critique for their presentation as largely individual or familial qualities, and their negation of social and structural pressures, there has been more limited attention paid to the potential of the concepts if they were put to work in a different way. This article attempts to sketch out ways in which the fundamentally relational aspects of the concepts of responsibility and resilience can be brought to the fore. In doing so, it builds on Rose and Lentzos’s argument that we should perhaps ‘argue not against responsibility and resilience but on the territory of responsibilities and resiliencies’ and sets out the case for engaging with, rather than withdrawing from or resisting discussions of the meanings and uses of these concepts, in tandem. Extending the work of Bourdieu and Wacquant, it argues for the need to turn the lens on the structures and mechanisms of power which promote and maintain inequality and divisive complex social relations, which undermine the possibility of collective ‘resilience’. The article advocates our collective ‘responsibility’ as engaging in processes that challenge and redefine these practices and structures to enable resistance and progressive action

    Nonlocality of Kohn-Sham exchange-correlation fields in dielectrics

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    The theory of the macroscopic field appearing in the Kohn-Sham exchange-correlation potential for dielectric materials, as introduced by Gonze, Ghosez and Godby, is reexamined. It is shown that this Kohn-Sham field cannot be determined from a knowledge of the local state of the material (local crystal potential, electric field, and polarization) alone. Instead, it has an intrinsically nonlocal dependence on the global electrostatic configuration. For example, it vanishes in simple transverse configurations of a polarized dielectric, but not in longitudinal ones.Comment: 4 pages, two-column style with 2 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#dv_gg
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