1,715 research outputs found

    Black Holes in the Presence of Cosmological Constant and Large N Brane World

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    Analytic form has been obtained for four-dimensional black holes with a minimal Hawking temperature in a theory with cosmological constant, dilaton and gauge fields. In general dimensions, black hole solutions are shown to exist and their asymptotic behaviors are obtained. In theories of ten dimension, N coincident D3-branes as the boundary of an AdS5AdS_5 space are constructed by embedding black D3-branes, with a five-dimensional compactified space of negligible size if N is large, which provide natural realizations of the Randall-Sundrum scenario. For this AdS5AdS_{5} background, the cosmological constant is a higher order perturbation and its effect on the spectra of standard model fields on the branes can be calculated.Comment: 12 pages, no figure

    Negative Prognostic Effect of Baseline Antipsychotic Exposure in Clinical High Risk for Psychosis (CHR-P): Is Pre-Test Risk Enrichment the Hidden Culprit?

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    INTRODUCTION: Sample enrichment is a key factor in contemporary early-detection strategies aimed at the identification of help-seekers at increased risk of imminent transition to psychosis. We undertook a meta-analytic investigation to ascertain the role of sample enrichment in the recently highlighted negative prognostic effect of baseline antipsychotic (AP) exposure in clinical high-risk (CHR-P) of psychosis individuals. METHODS: Systematic review and meta-analysis of all published studies on CHR-P were identified according to a validated diagnostic procedure. The outcome was the proportion of transition to psychosis, which was calculated according to the Freeman‐Tukey double arcsine transformation. RESULTS: Thirty-three eligible studies were identified, including 16 samples with details on AP exposure at baseline and 17 samples with baseline AP exposure as exclusion criterion for enrollment. Those with baseline exposure to AP (n = 395) had higher transition rates (29.9%; 95% CI: 25.1%–34.8%) than those without baseline exposure to AP in the same study (n = 1289; 17.2%; 15.1%–19.4%) and those coming from samples that did not include people who were exposed to AP at baseline (n = 2073; 16.2%; 14.6%–17.8%; P < .05 in both the fixed-effects and the random-effects models). Heterogeneity within studies was substantial, with values above 75% in all comparisons. CONCLUSIONS: Sample enrichment is not a plausible explanation for the higher risk of transition to psychosis of CHR-P individuals who were already exposed to AP at the enrollment in specialized early-detection programs. Baseline exposure to AP at CHR-P assessment is a major index of enhanced, imminent risk of psychosis

    Economic globalization and the fracturing of business interest representation in the European Union

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    Individual firms have become the dominant lobby actors in the European Union, while associational business interest representation has declined. This is alarming because individual firms tend to overlook the long-term interests of society by focusing on what is important in the short term for their own survival. How can we explain this trend? This article argues that globalization is a key driver of firm-level lobbying and that it fractures business interest representation. The study employs an original dataset of almost 14,000 lobby contacts between senior staff of the European Commission, business interests, and NGOs. It finds support for the argument that globalization spurs individual firm lobbying in the European Union. This complicates the already challenging task of business associations aggregating and channeling the interests of their members

    Generation of half-space sound fields with application to personal sound systems

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    A method is presented for generating a sound field that is significantly attenuated over half of the reproduction region, which has application to the generation of two independent sound fields for two listeners. The half-space sound field is produced by attenuating the negative or positive modes in the cylindrical or spherical expansion of a plane wave or point source sound field. It is shown that this is equivalent to adding to the original sound field, in quadrature, a second field which is the Hilbert transform of the original field. The resulting analytic field has a small magnitude in one half of the plane. Methods are presented for controlling the attenuation in the unwanted half-space. Finally, a simulation is presented showing the generation of a wideband pulse that propagates across half of the area within a circular array of sources

    Controlled transport of matter waves in two-dimensional optical lattices

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    We propose a method for achieving dynamically controllable transport of highly mobile matter-wave solitons in a driven two-dimensional optical lattice. Our numerical analysis based on the mean-field model and the theory based on the time-averaging approach, demonstrate that a fast time-periodic rocking of the two-dimensional optical lattice enables efficient stabilization and manipulation of spatially localized matter wavepackets via induced reconfigurable mobility channels.Comment: 4 pages, 4 figure

    Rotating Solution of Einstein-Maxwell Dilaton Gravity with Unusual Asymptotics

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    We study electrically charged, dilaton black holes, which possess infinitesimal angular momentum in the presence of one or two Liouville type potentials. These solutions are neither asymptotically flat nor (anti)-de Sitter. Some properties of the solutions are discussed.Comment: 11 pages, Accepted (Int. J. Theor. Phys.
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