18,839 research outputs found
The Virtual Runner Learning Game
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
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
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
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
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
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 Lentzosâs argument that we should perhaps âargue not against responsibility and resilience but on the territory of responsibilities and resilienciesâ 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 âresilienceâ. The article advocates our collective âresponsibilityâ 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
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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