15,121 research outputs found

    Zero-temperature criticality in the two-dimensional gauge glass model

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    The zero-temperature critical state of the two-dimensional gauge glass model is investigated. It is found that low-energy vortex configurations afford a simple description in terms of gapless, weakly interacting vortex-antivortex pair excitations. A linear dielectric screening calculation is presented in a renormalization group setting that yields a power-law decay of spin-wave stiffness with distance. These properties are in agreement with low-temperature specific heat and spin-glass susceptibility data obtained in large-scale multi-canonical Monte Carlo simulations.Comment: 4 pages, 4 figure

    A systematic review of neuroprotective strategies after cardiac arrest: from bench to bedside (Part I - Protection via specific pathways).

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    Neurocognitive deficits are a major source of morbidity in survivors of cardiac arrest. Treatment options that could be implemented either during cardiopulmonary resuscitation or after return of spontaneous circulation to improve these neurological deficits are limited. We conducted a literature review of treatment protocols designed to evaluate neurologic outcome and survival following cardiac arrest with associated global cerebral ischemia. The search was limited to investigational therapies that were utilized to treat global cerebral ischemia associated with cardiac arrest. In this review we discuss potential mechanisms of neurologic protection following cardiac arrest including actions of several medical gases such as xenon, argon, and nitric oxide. The 3 included mechanisms are: 1. Modulation of neuronal cell death; 2. Alteration of oxygen free radicals; and 3. Improving cerebral hemodynamics. Only a few approaches have been evaluated in limited fashion in cardiac arrest patients and results show inconclusive neuroprotective effects. Future research focusing on combined neuroprotective strategies that target multiple pathways are compelling in the setting of global brain ischemia resulting from cardiac arrest

    Steady-State Analysis of Load Balancing with Coxian-22 Distributed Service Times

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    This paper studies load balancing for many-server (NN servers) systems. Each server has a buffer of size b1,b-1, and can have at most one job in service and b1b-1 jobs in the buffer. The service time of a job follows the Coxian-2 distribution. We focus on steady-state performance of load balancing policies in the heavy traffic regime such that the normalized load of system is λ=1Nα\lambda = 1 - N^{-\alpha} for 0<α<0.5.0<\alpha<0.5. We identify a set of policies that achieve asymptotic zero waiting. The set of policies include several classical policies such as join-the-shortest-queue (JSQ), join-the-idle-queue (JIQ), idle-one-first (I1F) and power-of-dd-choices (Podd) with d=O(NαlogN)d=O(N^\alpha\log N). The proof of the main result is based on Stein's method and state space collapse. A key technical contribution of this paper is the iterative state space collapse approach that leads to a simple generator approximation when applying Stein's method

    η\eta-meson in nuclear matter

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    The η\eta-nucleon (η\etaN) interactions are deduced from the heavy baryon chiral perturbation theory up to the next-to-leading-order terms. Combining the relativistic mean-field theory for nucleon system, we have studied the in-medium properties of η\eta-meson. We find that all the elastic scattering η\etaN interactions come from the next-to-leading-order terms. The η\eta N sigma term is found to be about 280±\pm130 MeV. The off-shell terms are also important to the in-medium properties of η\eta-meson. On application of the latest determination of the η\etaN scattering length, the ratio of η\eta-meson effective mass to its vacuum value is near 0.84±0.0150.84\pm0.015, while the optical potential is about (83±5)-(83\pm5) MeV, at the normal nuclear density.Comment: 8 pages, 3 figures, to appear in PRC, many modification

    Assessing individual dietary intake in food sharing scenarios with food and human pose detection

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    Food sharing and communal eating are very common in some countries. To assess individual dietary intake in food sharing scenarios, this work proposes a vision-based approach to first capturing the food sharing scenario with a 360-degree camera, and then using a neural network to infer different eating states of each individual based on their body pose and relative positions to the dishes. The number of bites each individual has taken of each dish is then deduced by analyzing the inferred eating states. A new dataset with 14 panoramic food sharing videos was constructed to validate our approach. The results show that our approach is able to reliably predict different eating states as well as individual’s bite count with respect to each dish in food sharing scenarios

    Multiband effects on beta-FeSe single crystals

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    We present the upper critical fields Hc2(T) and Hall effect in beta-FeSe single crystals. The Hc2(T) increases as the temperature is lowered for field applied parallel and perpendicular to (101), the natural growth facet of the crystal. The Hc2(T) for both field directions and the anisotropy at low temperature increase under pressure. Hole carriers are dominant at high magnetic fields. However, the contribution of electron-type carriers is significant at low fields and low temperature. Our results show that multiband effects dominate Hc2(T) and electronic transport in the normal state

    Two dimensional Dirac fermions and quantum magnetoresistance in CaMnBi2_2

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    We report two dimensional Dirac fermions and quantum magnetoresistance in single crystals of CaMnBi2_2. The non-zero Berry's phase, small cyclotron resonant mass and first-principle band structure suggest the existence of the Dirac fermions in the Bi square nets. The in-plane transverse magnetoresistance exhibits a crossover at a critical field BB^* from semiclassical weak-field B2B^2 dependence to the high-field unsaturated linear magnetoresistance (120\sim 120% in 9 T at 2 K) due to the quantum limit of the Dirac fermions. The temperature dependence of BB^* satisfies quadratic behavior, which is attributed to the splitting of linear energy dispersion in high field. Our results demonstrate the existence of two dimensional Dirac fermions in CaMnBi2_2 with Bi square nets.Comment: 5 pages, 4 figure

    Evolution of population with sexual and asexual reproduction in changing environment

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    Using a lattice model based on Monte Carlo simulations, we study the role of the reproduction pattern on the fate of an evolving population. Each individual is under the selection pressure from the environment and random mutations. The habitat ("climate") is changing periodically. Evolutions of populations following two reproduction patterns are compared, asexual and sexual. We show, via Monte Carlo simulations, that sexual reproduction by keeping more diversified populations gives them better chances to adapt themselves to the changing environment. However, in order to obtain a greater chance to mate, the birth rate should be high. In the case of low birth rate and high mutation probability there is a preference for the asexual reproduction.Comment: 11 pages including figs., for Int. J. Mod. Phys. C 15, issue 2 (2004
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