901 research outputs found

    Concentration indices of income related self-reported health: a meta-regression analysis

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    Proliferating evidence reporting on standardised cross-country concentration indexes of income related self-reported health is increasingly being used for policy evaluation. Nonetheless, limited efforts have been put forward to examine the extent to which such evidence is subject to any specific methodological and publication biases, given that studies rely upon survey data form different samples and both heterogeneous health system institutions and empirical strategies. We conduct the first study drawing upon appropriate statistical methods to examine the presence of publication bias in the health economics literature measuring health inequalities of self-reported health. We test for other biases including the effect of precision estimates based on meta-regression analysis (MRA). We account for a set of biases in estimates of income-related health inequalities that rely on concentration index-related methods and self-reported health measures. Our findings suggest evidence of publication bias that primarily depends on the cardinalisation of self-reported health and some evidence of study-specific precision

    New topologies in pentanuclear nickel/oximato clusters: structural and magnetic characterization

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    In the present work, five new Ni5 clusters employing the versatile 2-pyridylcyanoxime ligand have been synthesized and chemically, structurally, and magnetically characterized. The crystallographic examination of these Ni5 clusters together with those already published in the literature, giving a total number of 14 complexes, exhibiting up to 8 different topologies for which the relationship between topology, reaction conditions and magnetic response has been analyzed. DC magnetic measurements were carried in the 300-2 K range for the new complexes and the analysis of the experimental data revealed an antiferromagnetic response for the oximato mediated interactions with a variety of ground states (S = 0, 1, 3) as function of the cluster topology

    A new scenario for string unification

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    We present a new scenario for gauge coupling unification in flipped SU(5) string models, which identifies the M32M_{32} scale of SU(3) and SU(2) unification with the empirical MLEP∌1015−16M_{\rm LEP}\sim10^{15-16}~GeV scale, and the M51M_{51} scale of SU(5) and U(1) unification with the theoretical Mstring∌5×1017M_{\rm string}\sim5\times10^{17}~GeV string unification scale. The vacuum shift necessary for the cancellation of the anomalous UA(1)\rm U_A(1) and an SU(4) hidden sector with fractionally-charged particles, play a crucial role in the dynamical determination of all intermediate mass scales in this scenario.Comment: 8 pages, LaTeX, 2 figures (uuencoded

    Constraints on the ionizing flux emitted by T Tauri stars

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    We present the results of an analysis of ultraviolet observations of T Tauri Stars (TTS). By analysing emission measures taken from the literature we derive rates of ionizing photons from the chromospheres of 5 classical TTS in the range ~10^41-10^44 photons/s, although these values are subject to large uncertainties. We propose that the HeII/CIV line ratio can be used as a reddening-independent indicator of the hardness of the ultraviolet spectrum emitted by TTS. By studying this line ratio in a much larger sample of objects we find evidence for an ionizing flux which does not decrease, and may even increase, as TTS evolve. This implies that a significant fraction of the ionizing flux from TTS is not powered by the accretion of disc material onto the central object, and we discuss the significance of this result and its implications for models of disc evolution. The presence of a significant ionizing flux in the later stages of circumstellar disc evolution provides an important new constraint on disc photoevaporation models.Comment: 8 pages, 5 figures. Accepted for publication in MNRA
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