181 research outputs found

    Political Elites in Federalized Countries: The Case of Spain (1980-2005). CES Working Paper, no. 146, 2008

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    This paper explores the social profile of the regional elite that has emerged in Spain since the de-mocratization and federalization of the country. For the first time, researchers present data about crucial variables like gender, place of birth, age, education, and profession. They make inter-regional comparisons, put their data on an international perspective, and try to explain some un-expected findings, such as the behavior of political elites in Catalonia and Castile-La Mancha. The authors compare also the social profile of MPs of the two largest parties and show that the gap between society and political elite has been reduced over the years. The paper offers a research agenda

    Precise determination of the structure factor and contact in a unitary Fermi gas

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    We present a high-precision determination of the universal contact parameter in a strongly interacting Fermi gas. In a trapped gas at unitarity we find the contact to be 3.06±0.083.06 \pm 0.08 at a temperature of 0.08 of the Fermi temperature in a harmonic trap. The contact governs the high-momentum (short-range) properties of these systems and this low temperature measurement provides a new benchmark for the zero temperature homogeneous contact. The experimental measurement utilises Bragg spectroscopy to obtain the dynamic and static structure factors of ultracold Fermi gases at high momentum in the unitarity and molecular Bose-Einstein condensate (BEC) regimes. We have also performed quantum Monte Carlo calculations of the static properties, extending from the weakly coupled Bardeen-Cooper-Schrieffer (BCS) regime to the strongly coupled BEC case, which show agreement with experiment at the level of a few percent.Comment: Replaced with accepted versio

    Weak Lensing of the CMB by Large-Scale Structure

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    Several recent papers have studied lensing of the CMB by large-scale structures, which probes the projected matter distribution from z=103z=10^3 to z0z\simeq 0. This interest is motivated in part by upcoming high resolution, high sensitivity CMB experiments, such as APEX/SZ, ACT, SPT or Planck, which should be sensitive to lensing. In this paper we examine the reconstruction of the large-scale dark matter distribution from lensed CMB temperature anisotropies. We go beyond previous work in using numerical simulations to include higher order, non-Gaussian effects and study how well the quadratic estimator of \cite{Hu01a} is able to recover the input field. We also study contamination by kinetic Sunyaev-Zel'dovich signals, which is spectrally indistinguishable from lensed CMB anisotropies. We finish by estimating the sensitivity of the previously cited experiments.Comment: 26 pages, 13 figures, replaced to match the minor revisions of the accepted versio

    Potential sources of contamination to weak lensing measurements: constraints from N-body simulations

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    We investigate the expected correlation between the weak gravitational shear of distant galaxies and the orientation of foreground galaxies, through the use of numerical simulations. This shear-ellipticity correlation can mimic a cosmological weak lensing signal, and is potentially the limiting physical systematic effect for cosmology with future high-precision weak lensing surveys. We find that, if uncorrected, the shear-ellipticity correlation could contribute up to 10% of the weak lensing signal on scales up to 20 arcminutes, for lensing surveys with a median depth z=1. The most massive foreground galaxies are expected to cause the largest correlations, a result also seen in the Sloan Digital Sky Survey. We find that the redshift dependence of the effect is proportional to the lensing efficiency of the foreground, and this offers prospects for removal to high precision, although with some model dependence. The contamination is characterised by a weakly negative B-mode, which can be used as a diagnostic of systematic errors. We also provide more accurate predictions for a second potential source of error, the intrinsic alignment of nearby galaxies. This source of contamination is less important, however, as it can be easily removed with distance information.Comment: 12 pages, 10 figures. Version accepted by MNRA
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