2,944 research outputs found

    State Level Earned Income Tax Credit’s Effects on Race and Age: An Effective Poverty Reduction Policy

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    In this paper, I analyze the effectiveness of state level Earned Income Tax Credit programs on improving of poverty levels. I conducted this analysis for the years 1991 through 2011 using a panel data model with fixed effects. The main independent variables of interest were the state and federal EITC rates, minimum wage, gross state product, population, and unemployment all by state. I determined increases to the state EITC rates provided only a slight decrease to both the overall white below-poverty population and the corresponding white childhood population under 18, while both the overall and the under-18 black population for this category realized moderate decreases in their poverty rates for the same time period. I also provide a comparison of the effectiveness of the state level EITCs and minimum wage at the state level over the same time period on these select demographic groups

    Concert II

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    Program listing performers and works performe

    Asymmetric Quark/Antiquark Hadronization in e+e- Annihilation

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    We point out that the fragmentation of a strange quark into nucleons versus antinucleons is not necessarily identical Dp/s(z,Q2)Dpˉ/s(z,Q2)D_{p/s}(z,Q^2) \neq D_{\bar p/s}(z,Q^2), even though the perturbative contributions from gluon splitting and evolution are ppˉp \leftrightarrow \bar p symmetric. The observation of such asymmetries in the hadronization of strange and other heavy quarks can provide insight into the nonperturbative mechanisms underlying jet fragmentation in QCD.Comment: Latex, 12 page

    Chiral-odd transversity spin structure function h1(x)h_1(x) of the nucleon in a constituent quark model

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    We study the chiral-odd transversity spin-dependent quark distribution function h1(x)h_1 (x) of the nucleon in a constituent quark model. The twist-2 structure functions, f1(x)f_1(x), g1(x)g_1(x) and h1(x)h_1(x) are calculated within the diquark spectator approximation. Whereas an inequality f1(x)>h1(x)>g1(x)f_1(x) > h_1(x) > g_1(x) holds with the interaction between quark and diquark being scalar, the axial-vector effective quark-diquark interaction, which contributes to the dd-quark distribution, does not lead to such a simple relation. We find that h1(x)h_1(x) for the dd-quark becomes somewhat smaller than g1d(x)g_1^d (x), when we fix the model parameter to reproduce known other structure functions. We also include corrections due to the non-trivial structure of the constituent quark, which is modeled by the Goldstone boson dressing. This improves agreements of f1(x)f_1(x) and g1(x)g_1(x) with experiments, and brings further reduction of h1d(x)h_1^d(x) distribution. Consequences for semi-inclusive experiments are also discussed.Comment: 33 pages, latex with 13 figures, to appear in Nuclear Physics A, PostScript file is also available at http://WWW.physik.tu-muenchen.de/~ksuzuki/publication.htm

    Workshop to identify critical windows of exposure for children\u27s health: Neurobehavioral work group summary

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    Summarizes the deliberations of a work group charged with addressing specific questions relevant to risk estimation in developmental neurotoxicology. Importance of multiple factors addressing critical windows of exposure on neurological function; Role that compensatory mechanisms play in the manifestation of the effects of developmental exposures

    Nucleon quark distributions in a covariant quark-diquark model

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    Spin-dependent and spin-independent quark light-cone momentum distributions and structure functions are calculated for the nucleon. We utilize a modified Nambu-Jona-Lasinio model in which confinement is simulated by eliminating unphysical thresholds for nucleon decay into quarks. The nucleon bound state is obtained by solving the Faddeev equation in the quark-diquark approximation, where both scalar and axial-vector diquark channels are included. We find excellent agreement between our model results and empirical data.Comment: 6 pages, 7 figure

    Polarized Parton Distributiions and Light-Front Dynamics

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    We present a consistent calculation of the structure functions within a light-front constituent quark model of the nucleon. Relativistic effects and the relevance of the covariance constraints are analyzed for both polarized and unpolarized parton distributions. Various models, which differ in their gluonic structure at the hadronic scale, are investigated. The results of the full covariant calculation are compared with those of a non-relativistic approximation to show the structure and magnitude of the differences.Comment: 31 pages, 9 figures, major revisio

    Interlayer c-axis transport in the normal state of cuprates

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    A theoretical model of c-axis transport properties in cuprates is proposed. Inter-plane and in-plane charge fluctuations make hopping between planes incoherent and diffusive (the in-plane momentum is not conserved after tunneling). The non-Drude optical conductivity σc(ω)\sigma_c(\omega) and the power-law temperature dependence of the {\it dc} conductivity are generically explained by the strong fluctuations excited in the process of tunneling. Several microscopic models of the charge fluctuation spectrum are considered.Comment: 8 page
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