7,617 research outputs found

    The default premium and corporate bond experience

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    A study that represents the first effort to tie together the differential returns required by holders of low-rated coporate bonds and the actual default experiences of these issues.Debt ; Corporate bonds

    Influence of carrier lifetime on quantum criticality and superconducting Tc of (TMTSF)_2ClO_4

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    This work presents and analyzes electrical resistivity data on the organic superconductor (TMTSF)2_2ClO4_4 and their anion substituted alloys (TMTSF)2_2(ClO4_4)1−x_{1-x}(ReO4_4)x_x along the least conducting c⋆c^\star axis. Nonmagnetic disorder introduced by finite size domains of anion ordering on non Fermi liquid character of resistivity is investigated near the conditions of quantum criticality. The evolution of the TT-linear resistivity term with anion disorder shows a limited decrease in contrast with the complete suppression of the critical temperature TcT_c as expected for unconventional superconductivity beyond a threshold value of xx. The resulting breakdown of scaling between both quantities is compared to the theoretical predictions of a linearized Boltzmann equation combined to the scaling theory of umklapp scattering in the presence of disorder induced pair-breaking for the carriers.Comment: 13 pages, 8 figure

    Properties of unique hard X-ray dips observed from GRS 1915+105 and IGR J17091-3624 and their implications

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    We report a comprehensive study on spectral and timing properties of hard X-ray dips uniquely observed in some so-called variability classes of the micro-quasars GRS 1915+105 and IGR J17091-3624. These dips are characterized by a sudden decline in the 2.0-60.0 keV X-ray intensity by a factor of 4-12 simultaneous with the increase in hardness ratio by a factor of 2-4. Using 31 observations of GRS 1915+105 with RXTE/PCA, we show that different behavior are observed in different types of variability classes, and we find that a dichotomy is observed between classes with abrupt transitions vs those with smoother evolution. For example, both energy-lag spectra and frequency-lag spectra of hard X-ray dips in classes with abrupt transitions and shorter dip intervals show hard-lag (hard photons lag soft photons), while both lag spectra during hard dips in classes with smoother evolution and longer dip intervals show soft-lag. Both lag time-scales are of the order of 100-600 msec. We also show that timing and spectral properties of hard X-ray dips observed in light curves of IGR J17091-3624 during its 2011 outburst are consistent with the properties of the abrupt transitions in GRS 1915+105 rather than smooth evolution. A global correlation between the X-ray intensity cycle time and hard dip time is observed for both abrupt and smooth transition which may be due to two distinct physical processes whose time-scales are eventually correlated. We discuss implications of our results in the light of some generic models.Comment: 17 pages, 5 figures, accepted for publication in the Astrophysical Journa

    Compatriot and foreigner : a study of impression formation in three countries

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    Caption title"February 5, 1957."At head of title: Communications Program. Experimental Section"350"--handwritten on coverIncludes bibliographical references (leaf 21

    Exploration of the Outer Limits: The Misdirected Evolution of Reckless Disregard

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