1,418 research outputs found

    Emergence of chaotic attractor and anti-synchronization for two coupled monostable neurons

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    The dynamics of two coupled piece-wise linear one-dimensional monostable maps is investigated. The single map is associated with Poincare section of the FitzHugh-Nagumo neuron model. It is found that a diffusive coupling leads to the appearance of chaotic attractor. The attractor exists in an invariant region of phase space bounded by the manifolds of the saddle fixed point and the saddle periodic point. The oscillations from the chaotic attractor have a spike-burst shape with anti-phase synchronized spiking.Comment: To be published in CHAO

    Synthesis And Characterization Of (pyNO−)2GaCl: A Redox-Active Gallium Complex

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    We report the synthesis of a gallium complex incorporating redox-active pyridyl nitroxide ligands. The (pyNO−)2GaCl complex was prepared in 85% yield via a salt metathesis route and was characterized by 1H and 13C NMR spectroscopies, X-ray diffraction, and theory. UV–Vis absorption spectroscopy and electrochemistry were used to access the optical and electrochemical properties of the complex, respectively. Our discussion focuses primarily on a comparison of the gallium complex to the corresponding aluminum derivative and shows that although the complexes are very similar, small differences in the electronic structure of the complexes can be correlated to the identity of the metal

    Socioeconomic Inequalities in Mortality Rates in Old Age in the World Health Organization Europe Region

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    Socioeconomic adversity is among the foremost fundamental causes of human suffering, and this is no less true in old age. Recent reports on socioeconomic inequalities in mortality rate in old age suggest that a low socioeconomic position continues to increase the risk of death even among the oldest old. We aimed to examine the evidence for socioeconomic mortality rate inequalities in old age, including information about associations with various indicators of socioeconomic position and for various geographic locations within the World Health Organization Region for Europe. The articles included in this review leave no doubt that inequalities in mortality rate by socioeconomic position persist into the oldest ages for both men and women in all countries for which information is available, although the relative risk measures observed were rarely higher than 2.00. Still, the available evidence base is heavily biased geographically, inasmuch as it is based largely on national studies from Nordic and Western European countries and local studies from urban areas in Southern Europe. This bias will hamper the design of European-wide policies to reduce inequalities in mortality rate. We call for a continuous update of the empiric evidence on socioeconomic inequalities in mortality rate

    Generalization of Kirchhoff's Law of Thermal Radiation: The Inherent Relations Between Quantum Efficiency and Emissivity

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    Planck's law of thermal radiation depends on the temperature, TT, and the emissivity, ϵ\epsilon, of a body, where emissivity is the coupling of heat to radiation that depends on both phonon-electron nonradiative interactions and electron-photon radiative interactions. Another property of a body is absorptivity, α\alpha, which only depends on the electron-photon radiative interactions. At thermodynamic equilibrium, nonradiative interactions are balanced, resulting in Kirchhoff's law of thermal radiation that equals these two properties, i.e., ϵ=α\epsilon = \alpha. For non-equilibrium, quantum efficiency (QEQE) describes the statistics of photon emission, which like emissivity depends on both radiative and nonradiative interactions. Past generalized Planck's equation extends Kirchhoff's law out of equilibrium by scaling the emissivity with the pump-dependent chemical-potential μ\mu, obscuring the relations between the body properties. Here we theoretically and experimentally demonstrate a prime equation relating these properties in the form of ϵ=α(1QE)\epsilon = \alpha(1-QE), which is in agreement with a recent universal modal radiation law for all thermal emitters. At equilibrium, these relations are reduced to Kirchhoff's law. Our work lays out the fundamental evolution of non-thermal emission with temperature, which is critical for the development of lighting and energy devices.Comment: 14 pages, 16 figures. arXiv admin note: substantial text overlap with arXiv:2104.1013
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