1,964 research outputs found

    Near-threshold production of a0(980) mesons in the reaction pp -> d K^+ \bar{K}^0

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    Using an effective Lagrangian approach as well as the Quark-Gluon Strings Model we analyze near-threshold production of a0(980)-mesons in the reaction NN -> d K \bar{K} as well as the background of non-resonant K\bar{K}-pair production. We argue that the reaction pp -> d K^+ \bar{K}^0 at an energy release Q<=100 MeV is dominated by the intermediate production of the a0(980)-resonance. At larger energies the non-resonant K^+\bar{K}^0-pair production - where the kaons are produced in a relative P-wave - becomes important. Then effects of final-state interactions are evaluated in a unitarized scattering-length approach and found to be in the order of a 20% suppression close to threshold. Thus in present experiments at the Cooler Synchrotron COSY-J\"ulich for Q<=107 MeV the a_0^+ signal can reliably be separated from the non-resonant K^+\bar{K^0} background.Comment: 14 pages, 12 figures, submitted to EPJ

    Production of a0a_0-mesons in the reactions πN→a0N\pi N \to a_0 N and pp→da0+p p \to d a_0^+ at GeV energies

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    We investigate the reactions πN→a0N\pi N \to a_0 N and pp→da0+p p \to d a_0^+ near threshold and at medium energies. An effective Lagragian approach and the Regge pole model are applied to analyze different contributions to the cross section of the reaction πN→a0N\pi N \to a_0 N. These results are used to calculate the differential and total cross sections of the reaction pp→da0+p p \to d a_0^+ within the framework of the two-step model in which two nucleons produce an a0a_0-meson via π\pi -meson exchange and fuse to a deuteron. The necessity of new measurements on a0a_0 production and branching fractions (of its decay to the KKˉK\bar K and πη\pi\eta channels) is emphasized for clarifying the a0a_0 structure. Detailed predictions for the reaction pp→da0+pp \to d a_0^+ are presented for the energy regime of the proton synchrotron COSY-J\"ulich.Comment: 9 pages, including 6 eps figure

    a0(980)-f0(980) mixing and isospin violation in the reactions pN -> d a0, pd -> 3He/3H a0 and dd -> 4He a0

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    It is demonstrated that f_0-a_0 mixing can lead to a comparatively large isospin violation in the reactions pN -> da_0, pd -> ^3He/^3H a_0 and dd -> ^4He a_0 close to the corresponding production thresholds. The observation of such mixing effects is possible, e.g., by measuring the forward-backward asymmetry in the reaction pn -> d a_0^0 -> d eta pi^0.Comment: 14 pages, 5 figure

    Methamphetamine and Inflammatory Cytokines Increase Neuronal Na+/K+-ATPase Isoform 3: Relevance for HIV Associated Neurocognitive Disorders

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    Methamphetamine (METH) abuse in conjunction with human immunodeficiency virus (HIV) exacerbates neuropathogenesis and accelerates neurocognitive impairments in the central nervous system (CNS), collectively termed HIV Associated Neurocognitive Disorders (HAND). Since both HIV and METH have been implicated in altering the synaptic architecture, this study focused on investigating alterations in synaptic proteins. Employing a quantitative proteomics approach on synaptosomes isolated from the caudate nucleus from two groups of rhesus monkeys chronically infected with simian immunodeficiency virus (SIV) differing by one regimen, METH treatment, we identified the neuron specific Na+/K+-ATPase alpha 1 isoform 3 (ATP1A3) to be up regulated after METH treatment, and validated its up regulation by METH in vitro. Further studies on signaling mechanisms revealed that the activation of ATP1A3 involves the extracellular regulated kinase (ERK) pathway. Given its function in maintaining ionic gradients and emerging role as a signaling molecule, changes in ATP1A3 yields insights into the mechanisms associated with HAND and interactions with drugs of abuse

    Tau-tubulin kinase 1 (TTBK1), a neuron-specific tau kinase candidate, is involved in tau phosphorylation and aggregation

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    Neurofibrillary tangles, which are major pathological hallmarks of Alzheimer’s disease (AD), are composed of paired helical filaments (PHFs) containing hyperphosphorylated tau. Specific kinases regulate tau phosphorylation and are closely linked to the pathogenesis of AD. We have characterized a human tau-tubulin kinase 1 (TTBK1) gene located on chromosome 6p21.1. TTBK1 is a serine/threonine/tyrosine kinase that is conserved among species and belongs to the casein kinase 1 superfamily. It is specifically expressed in the brain, especially in the cytoplasm of cortical and hippocampal neurons. TTBK1 phosphorylates tau proteins in both a Mg2+- and a Mn2+-dependent manner. Phosphopeptide mapping and immunoblotting analysis confirmed a direct tau phosphorylation by TTBK1 at Ser198, Ser199, Ser202 and Ser422, which are also phosphorylated in PHFs. TTBK1 also induces tau aggregation in human neuronal cells in a dose-dependent manner. We conclude that TTBK1 is a neuron-specific dual kinase involved in tau phosphorylation at AD-related sites and is also associated with tau aggregation

    Judaic Journeys at the University of Michigan: from Belser to Frankel to Hermelin

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    Judaic studies represnts a very wife range of subject disciplines including philosophy, religion, history, folklore, political science, law, education, music, art and architecture, languages and literature, medicine, and many others. "Judaic Journeys" explores the information resources collected to support this field since the University of Michigan's founding in 1817.http://deepblue.lib.umich.edu/bitstream/2027.42/120257/1/judaic_journeys_00.pd

    Medium effects in the production and pi0 gamma decay of omega-mesons in pA collisions in the GeV region

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    The omega-resonance production and its pi0 gamma decay in p-A reactions close to threshold is considered within the Intranuclear Cascade (INC) Model. The pi0 gamma invariant mass distribution shows two components which correspond to the omega decay 'inside' and 'outside' the nucleus, respectively. The 'inside' component is distorted by medium effects, which introduce a mass shift as well as collisional broadening for the omega-meson and its decaying pion. The relative contribution of the 'inside' component is analyzed in detail for different kinematical conditions and nuclear targets. It is demonstrated that a measurement of the correlation in azimuthal angle between the pi0 and gamma momenta allows to separate events related to the 'inside' omega decay from different sources of background when uncorrelated pi0's and gamma's are produced.Comment: 24 pages, 11 figure
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