19,052 research outputs found

    Child Health and the Income Gradient: Evidence from Australia

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    The positive relationship between household income and child health is well documented in the child health literature but the precise mechanisms via which income generates better health and whether the income gradient is increasing in child age are not well understood. This paper presents new Australian evidence on the child health-income gradient. We use data from the Longitudinal Survey of Australian (LSAC), which involved two waves of data collection for children born between March 2003 and February 2004 (B-Cohort), and between March 1999 and February 2000 (K-Cohort). This data set allows us to test the robustness of some of the findings of the influential studies of Case et al. (2002) and J.Currie and Stabile (2003), and a recent study by A.Currie et al. (2007) , using a sample of Australian children. The richness of the LSAC data set also allows us to conduct further exploration of the determinants of child health. Our results reveal an increasing income gradient by child age using similar covariates to Case et al. (2002). However, the income gradient disappears if we include a rich set of controls. Our results indicate that parental health and, in particular, the mother's health plays a significant role, reducing the income coefficient to zero. Thus, our results for Australian children are similar to those produced by Propper et al. (2007) on their British child cohort. We also find some evidence that higher incomes have a protective effect when health shocks do arise: for several chronic conditions, children from higher-income households are less likely to be reported as being in poor health than children from lower-income households who have the same chronic conditions. The latter result is similar to some recent findings by Condliffe and Link (2008) on a sample of US children.Child health, Income gradient, Parental health, Nutrition, Panel data, Australia

    Classical stability of U(1)_A domain walls in dense matter QCD

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    It was recently shown that there exists metastable U(1)_A domain wall configurations in high-density QCD (\mu >> 1 GeV). In the following we will assess the stability of such non-trivial field configurations at intermediate densities (\mu < 1 GeV). The existence of such configurations at intermediate densities could have interesting consequences for the physics of neutron stars with high core density.Comment: 13 pages, 2 Postscript figures, typos correcte

    Charged and superconducting vortices in dense quark matter

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    Quark matter at astrophysical densities may contain stable vortices due to the spontaneous breaking of hypercharge symmetry by kaon condensation. We argue that these vortices could be both charged and electrically superconducting. Current carrying loops (vortons) could be long lived and play a role in the magnetic and transport properties of this matter. We provide a scenario for vorton formation in protoneutron stars.Comment: Replaced with the published version. A typographical error in Eq. 2 is correcte

    Pion Propagation near the QCD Chiral Phase Transition

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    We point out that, in analogy with spin waves in antiferromagnets, all parameters describing the real-time propagation of soft pions at temperatures below the QCD chiral phase transition can be expressed in terms of static correlators. This allows, in principle, the determination of the soft pion dispersion relation on the lattice. Using scaling and universality arguments, we determine the critical behavior of the parameters of pion propagation. We predict that when the critical temperature is approached from below, the pole mass of the pion drops despite the growth of the pion screening mass. This fact is attributed to the decrease of the pion velocity near the phase transition.Comment: 8 pages (single column), RevTeX; added references, version to be published in PR

    Conformality Lost

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    We consider zero-temperature transitions from conformal to non-conformal phases in quantum theories. We argue that there are three generic mechanisms for the loss of conformality in any number of dimensions: (i) fixed point goes to zero coupling, (ii) fixed point runs off to infinite coupling, or (iii) an IR fixed point annihilates with a UV fixed point and they both disappear into the complex plane. We give both relativistic and non-relativistic examples of the last case in various dimensions and show that the critical behavior of the mass gap behaves similarly to the correlation length in the finite temperature Berezinskii-Kosterlitz-Thouless (BKT) phase transition in two dimensions, xi ~ exp(c/|T-T_c|^{1/2}). We speculate that the chiral phase transition in QCD at large number of fermion flavors belongs to this universality class, and attempt to identify the UV fixed point that annihilates with the Banks-Zaks fixed point at the lower end of the conformal window.Comment: 30 pages, 6 figures; v2: typos fixed, references adde
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