742 research outputs found

    THE SECOND DIVINE COUNCIL AT ODYSSEY 5.1–42 RECONSIDERED

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    This article reconsiders the much-discussed second divine council at the beginning of Book 5 of the Odyssey (5.1–42). It is demonstrated that this assembly is not a case of successive narration of simultaneous actions, as many scholars have maintained, but that the second council is necessary because Zeus, in order to avoid interdivine conflicts, has not kept his promise to initiate Odysseus’ repatriation as announced in the first council. It is further argued that Athene’s speech to Zeus (5.7–20), with its minacious tone and its cento-like composition, serves to put pressure on Zeus and to display Athene’s intellectual superiority

    Manifolds with small Dirac eigenvalues are nilmanifolds

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    Consider the class of n-dimensional Riemannian spin manifolds with bounded sectional curvatures and diameter, and almost non-negative scalar curvature. Let r=1 if n=2,3 and r=2^{[n/2]-1}+1 if n\geq 4. We show that if the square of the Dirac operator on such a manifold has rr small eigenvalues, then the manifold is diffeomorphic to a nilmanifold and has trivial spin structure. Equivalently, if M is not a nilmanifold or if M is a nilmanifold with a non-trivial spin structure, then there exists a uniform lower bound on the r-th eigenvalue of the square of the Dirac operator. If a manifold with almost nonnegative scalar curvature has one small Dirac eigenvalue, and if the volume is not too small, then we show that the metric is close to a Ricci-flat metric on M with a parallel spinor. In dimension 4 this implies that M is either a torus or a K3-surface

    Gender Effects on Lane Change Test (LCT) Performance

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    There are various easy-to-implement, low-cost methodologies for evaluating driver performance under distraction caused by in-vehicle tasks. One of them is the Lane Change Test (LCT), which is currently under consideration for becoming an ISO-standardized procedure. This paper investigates the effect of gender on LCT performance. Although a common procedure in psychological research, balancing for gender is not a requirement made by the ISO draft. However, using data from three LCT experiments, we found gender differences in LCT as well as secondary task performance. We conclude that subject samples balanced for gender are necessary to assure comparability of LCT results

    Local electronic structure of the peptide bond probed by resonant inelastic soft X-ray scattering.

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    The local valence orbital structure of solid glycine, diglycine, and triglycine is studied using soft X-ray emission spectroscopy (XES), resonant inelastic soft X-ray scattering (RIXS) maps, and spectra calculations based on density-functional theory. Using a building block approach, the contributions of the different functional groups of the peptides are separated. Cuts through the RIXS maps furthermore allow monitoring selective excitations of the amino and peptide functional units, leading to a modification of the currently established assignment of spectral contributions. The results thus paint a new-and-improved picture of the peptide bond, enhance the understanding of larger molecules with peptide bonds, and simplify the investigation of such molecules in aqueous environment

    Dynamical Model for Chemically Driven Running Droplets

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    We propose coupled evolution equations for the thickness of a liquid film and the density of an adsorbate layer on a partially wetting solid substrate. Therein, running droplets are studied assuming a chemical reaction underneath the droplets that induces a wettability gradient on the substrate and provides the driving force for droplet motion. Two different regimes for moving droplets -- reaction-limited and saturated regime -- are described. They correspond to increasing and decreasing velocities with increasing reaction rates and droplet sizes, respectively. The existence of the two regimes offers a natural explanation of prior experimental observations.Comment: 4 pages, 5 figure

    Chemical Waves in Media with State-Dependent Anisotropy

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    In the reduction of NO with H2 on a Rh(110) surface rectangularly shaped target patterns and spirals with sharp corners have been observed. These patterns can be reproduced with a simple model assuming that the (anisotropic) diffusion is state dependent. Such a dependence is realized in the system Rh(110)/NO + H2 by the presence of different adsorbate-induced reconstructions with varying substrate geometries

    The Chiral Condensate in a Finite Volume

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    Chiral perturbation theory at finite four-volume V (=L^3T) is reconsidered with a view towards finding a computational scheme that can deal with any value of M_\pi L, where M_\pi is a generic Nambu-Goldstone mass. The momentum zero modes that cause the usual p-expansion to fail in the chiral limit are treated separately, and partly integrated out to all orders. In this way the theory remains infrared finite in the perturbative expansion, and the chiral limit can be considered at finite volume. We illustrate the technique by computing the quark condensate in a finite volume, smoothly connecting standard results in the p-regime for larger masses with those of the epsilon-regime for smaller masses. From the partially quenched theory we also obtain the spectral density of the Dirac operator, a smooth function from the microscopic region to the bulk region of the p-regime.Comment: 33 pages, 10 figures, corrections in (4.7), (6.5), (6.8), additional comment on (3.16

    Size-Dependent Transition to High-Dimensional Chaotic Dynamics in a Two-Dimensional Excitable Medium

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    The spatiotemporal dynamics of an excitable medium with multiple spiral defects is shown to vary smoothly with system size from short-lived transients for small systems to extensive chaos for large systems. A comparison of the Lyapunov dimension density with the average spiral defect density suggests an average dimension per spiral defect varying between three and seven. We discuss some implications of these results for experimental studies of excitable media.Comment: 5 pages, Latex, 4 figure
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