83 research outputs found

    Azimuthal Charged-Particle Correlations and Possible Local Strong Parity Violation

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    Parity-odd domains, corresponding to nontrivial topological solutions of the QCD vacuum, might be created during relativistic heavy-ion collisions. These domains are predicted to lead to charge separation of quarks along the system’s orbital momentum axis. We investigate a three-particle azimuthal correlator which is a P even observable, but directly sensitive to the charge separation effect. We report measurements of charged hadrons near center-of-mass rapidity with this observable in Au+Au and Cu+Cu collisions at √sNN=200  GeV using the STAR detector. A signal consistent with several expectations from the theory is detected. We discuss possible contributions from other effects that are not related to parity violation

    Coherent diffractive photoproduction of rho(0) mesons on gold nuclei at 200 GeV/nucleon-pair at the Relativistic Heavy Ion Collider

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    Beam Energy Dependence of Jet-Quenching Effects in Au plus Au Collisions at root s(NN)=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV

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    We report measurements of the nuclear modification factor, RCPR_{ \mathrm{CP}}, for charged hadrons as well as identified π+()\pi^{+(-)}, K+()K^{+(-)}, and p(p)p(\overline{p}) for Au+Au collision energies of sNN\sqrt{s_{_{ \mathrm{NN}}}} = 7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-pTp_{\mathrm{T}} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra, but is also very similar for the kaon spectra. While the magnitude of the proton RCPR_{ \mathrm{CP}} at high pTp_{\mathrm{T}} does depend on collision energy, neither the proton nor the anti-proton RCPR_{ \mathrm{CP}} at high pTp_{\mathrm{T}} exhibit net suppression at any energy. A study of how the binary collision scaled high-pTp_{\mathrm{T}} yield evolves with centrality reveals a non-monotonic shape that is consistent with the idea that jet-quenching is increasing faster than the combined phenomena that lead to enhancement.We report measurements of the nuclear modification factor RCP for charged hadrons as well as identified π+(-), K+(-), and p(p¯) for Au+Au collision energies of sNN=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-pT net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton RCP at high pT does depend on the collision energy, neither the proton nor the antiproton RCP at high pT exhibit net suppression at any energy. A study of how the binary collision-scaled high-pT yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement

    Harmonic decomposition of three-particle azimuthal correlations at energies available at the BNL Relativistic Heavy Ion Collider

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    Passionate forms and the problem of subjectivity: Freud, Frau Emmy von N. and the unconscious communication of affect

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    This article considers the transfer and circulation of affects in Freud’s first clinical case, ‘Emmy Von N.’ We are especially concerned to tease out the unconscious communication of affects within Freud’s case study. In part, this is to contribute to an understanding of the relationship between affect and its representative, passionate, forms. In part, our close reading of the case study is also designed to contribute the recent debates about ‘the problem of subjectivity’. In our reading of the course of Emmy’s treatment and Freud’s therapeutic interventions, we disclose the unconscious communication between them, especially involving the transfer of affects – with Emmy insisting on their passionate nature and Freud’s attempts to undermine her passions. We argue that it is precisely through appreciating the unconscious exchange of affects and their passionate forms that Freud came to understand the possibility of new forms for those passions

    Epigenetic silencers are enriched in dormant desert frog muscle

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    Green-striped burrowing frogs, Cyclorana alboguttata, survive droughts by entering a metabolic depression called aestivation, characterised by a reduction in resting oxygen consumption by 80%. Aestivation in C. alboguttata is manifest by transcriptional silencing of skeletal muscle bioenergetic genes, such as NADH ubiquinone oxidoreductase 1, ATP synthase and superoxide dismutase 2. In this study, we hypothesised that aestivation is associated with epigenetic change in frog muscle. We assessed mRNA transcript abundance of seven genes that code for proteins with established roles in epigenetically-mediated gene silencing [transcriptional co-repressor SIN3A, DNA (cytosine-5-) methyltransferase 1, methyl CpG binding protein 2, chromodomain helicase DNA binding protein 4, histone binding protein rbbp4, histone deacetylase 1 and nuclear receptor co-repressor 2] using qRT-PCR. These seven genes showed a modest (1.1-3.5-fold) but coordinated upregulation in 6-month aestivating muscle. This reached significance for SIN3A and DNA cytosine-5-methyltransferase 1 in standard pair-wise comparisons (p < 0.05), and the candidates as a whole when analysed by Fisher's combined probability test (p < 0.01). These data are consistent with the hypothesis that the transcriptional silencing and metabolic depression that occurs during seasonal dormancy are associated with chromatin remodelling, and present a novel example of an environmentally induced epigenetic modification in an adult vertebrate
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