670 research outputs found

    System size and beam energy dependence of azimuthal anisotropy from PHENIX

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    We present azimuthal anisotropy measurements in Au+Au and Cu+Cu collisions at sNN\sqrt{s_{NN}} = 62.4 and 200 GeV. Comparison between reaction plane and cumulant v2v_2 measurements in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV show that non-flow contributions, originating mainly from jets, influence the extracted v2v_2 for pTp_T \gtrsim 3.5 GeV/c. Number of constituent quark (NCQ) scaling of v2v_2, when studied as a function of transverse kinetic energy KETKE_T, is seen to hold for Au+Au collisions at sNN\sqrt{s_{NN}} = 62.4 and 200 GeV and for Cu+Cu collisions at sNN\sqrt{s_{NN}} = 200 GeV for KETKE_{T} \lesssim 1 GeV/c. Differential hexadecupole flow v4v_4 seems to exhibit scaling with integral v2v_2 for centrality \le 40% as has been observed for differential v2v_2.Comment: 4 pages, 3 figures, Proceedings of the QM2008 Conference, Jaipur, India February 4-10 200

    Universal scaling of the elliptic flow data at RHIC

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    Recent PHOBOS measurements of the excitation function for the pseudo-rapidity dependence of elliptic flow in Au+Au collisions at RHIC, have posed a significant theoretical challenge. Here we show that these differential measurements, as well as the RHIC measurements on transverse momentum satisfy a universal scaling relation predicted by the Buda-Lund model, based on exact solutions of perfect fluid hydrodynamics. We also show that recently found transverse kinetic energy scaling of the elliptic flow is a special case of this universal scaling.Comment: 4 pages, 3 figures, 1 tabl

    Conference Reports

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    Decomposition of Harmonic and Jet Contributions to Particle-pair Correlations at Ultra-relativistic Energies

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    Methodology is presented for analysis of two-particle azimuthal angle correlation functions obtained in collisions at ultra-relativistic energies. We show that harmonic and di-jet contributions to these correlation functions can be reliably decomposed by two techniques to give an accurate measurement of the jet-pair distribution. Results from detailed Monte Carlo simulations are used to demonstrate the efficacy of these techniques in the study of possible modifications to jet topologies in heavy ion reactions.Comment: Updated version to be published in PRC Rapid Com

    Has the QCD Critical Point been Signaled by Observations at RHIC ?

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    The shear viscosity to entropy ratio (η/s\eta/s) is estimated for the hot and dense QCD matter created in Au+Au collisions at RHIC (sNN=200\sqrt{s_{NN}}=200 GeV). A very low value is found η/s0.1\eta/s \sim 0.1, which is close to the conjectured lower bound (1/4π1/4\pi). It is argued that such a low value is indicative of thermodynamic trajectories for the decaying matter which lie close to the QCD critical end point.Comment: 4 pages, 3 figures. Revised version, accepted for publication in PR

    Optimum temperature and stocking density for transportation of tilapia (Oreochromis niloticus) broodstock in the semi-arid zone of Nigeria

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    Oreochromis niloticus broodstock of mean weight 32.3g were cropped in the morning with dragnet from a 1 ha reservoir and transported in round tanks to the Hatchery complex of the National Institute for Freshwater Fisheries Research where they were stocked into 5m x 5m indoor concrete tanks filled with clean water and with aerators at a density of 4 fish/m1. They were acclimated for 5 days and then packaged into 60 liter capacity water proof bags at the following stocking densities: 60, 80, 100, 120, 140 fish/60 lit bag. Each stocking density had bags with ice blocks and bags without ice blocks in triplicate. The water proof bags were oxygenated, loaded into quick fitting plastic bowls and transported in a bus from New Bussa to Warra, Kebbi state, a journey of 3 hours. The trip was repeated four times. Percentage survival in bags with ice block were 100%for stocking densities 60, 80, 100 fish/60 lit bag, 95.1%for 120 fish/60 lit bag and 84. 7%for 1-10 fish/60 lit bag (mean temperature 23.5~?C). Mortalities were recorded in all the bags without ice block but the highest survival was in the bag with stocking density 60fish/60 lit bag (mean temperature 29.2~?C)

    Excitation functions of baryon anomaly and freeze-out properties at RHIC-PHENIX

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    The intermediate pTp_T region (2 - 5 GeV/cc) in central Au+Au collisions at RHIC has a rich physics content. The (anti)proton to pion ratio at the intermediate pTp_T gives us a powerful tool to investigate the bulk properties of the hot and dense matter created at RHIC and their hadronization processes. We present the preliminary results of identified charged hadron spectra at the lower beam energies at RHIC. The excitation function of (anti)proton to pion ratios from SPS to RHIC are shown. We also discuss the onset of the baryon enhancement at the high energy heavy ion collisions.Comment: 4 pages, 3 figures, Quark Matter 2006 conference proceeding

    Study of the relationship between HPA-1 and HPA-5 gene polymorphisms and refractory to platelet therapy and recombinant factor VII in glanzmann thrombasthenia patients in Southeast of Iran

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    Background: Glanzmann Thrombasthenia (GT) is a rare autosomal disease. HPA (Human Platelet Alloantigen) is a surface polymorphic alloantigen of platelets. This study was intended to investigate and compare the polymorphism of HPA-1 and HPA-5 genes in two groups of GT patients, with and without resistance to platelet and recombinant factor VII therapy. Materials and Methods: This case control study was performed on GT patients (n=16) with resistance to platelet therapy and recombinant factor VII and control group of GT patients (n=16) without resistance to platelet therapy and recombinant factor VII. The consent form was completed by each patient. Gene polymorphisms of HPA-1 and HPA-5 were investigated using SSP-PCR, and the obtained data were analyzed using statistical software SPSS16.0. Results: The results indicated no significant relationship between the studied genes and their resistance to platelet therapy and recombinant factor VII. The frequencies of HPA-1 genotype a/a were 98 and 94 in patient and control groups, respectively. The frequency of allele b was found to be less than allele a. The value of this allele was 4 in patient group and 1 in control group. In addition, the HPA-5a/a (98) was the most frequent alloantigen?? (check it) in both groups. Seven percent (7) of the patients had the HPA-5a/b genotype, and the HPA-5b/b was found to be absent in these individuals. Conclusion: According to the results obtained, it could be concluded that these genes play no role in resistance to platelet therapy. © 2018, Tehran University of Medical Sciences (TUMS). All rights reserved

    Multiparticle angular correlations: a probe for the sQGP at RHIC

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    A novel decomposition technique is used to extract the centrality dependence of di-jet properties and yields from azimuthal correlation functions obtained in Au+Au collisions at sNN\sqrt{s_{_{\rm NN}}}=200 GeV. The width of the near-side jet shows very little dependence on centrality. In contrast, the away-side jet indicates substantial broadening as well as hints for for a local minimum at Δϕ=π\Delta \phi=\pi for central and mid-central events. The yield of jet-pairs (per trigger particle) slowly increases with centrality for both the near- and away-side jets. These observed features are compatible with several recent theoretical predictions of possible modifications of di-jet fragmentation by a strongly interacting medium. Several new experimental approaches, including the study of flavor permutation and higher order multi-particle correlations, that might help to distinguish between different theoretical scenarios are discussed.Comment: Proceedings of the MIT workshop on correlations and fluctation

    Legume based pasture rejuvenation for greenhouse gas outcomes

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    Non-Peer ReviewedIncorporating legumes into a grass based pasture system has multiple benefits. A grass/legume blend increases the dietary protein of foraging cattle over grass alone. Furthermore, symbiotic biological nitrogen fixation introduces additional nitrogen to the pasture system thereby potentially lessening the need for synthetic fertilizers. However, over time, pastures initially seeded with a blend of grasses and legumes will tend towards increasing grass dominance such that the presence and benefits of legumes diminishes. Reestablishing legumes on a mature pasture can restore these important functions. By improving ruminant diet and therefore feed conversion ratios as well as decreasing nitrogen fertilizer applications, pasture rejuvenation, through the introduction of legumes, is expected to lower the greenhouse gas cost of grazing livestock on a per output basis. However, disturbance of soils, which can be part of various rejuvenation techniques, can result in losses of soil carbon thereby offsetting potential at least some of the greenhouse gas benefits. Sod-seeding may be an effective strategy to establish legumes in a mature pasture thereby incurring benefits without heavily disrupting soils and incurring soil carbon loss. To test this, a multiyear experiment, including cattle, vegetation (specifically the incorporation of non-bloat legumes: cicer milkvetch and sainfoin), soils and microbiota, was established near Lanigan, SK to examine the impact of sod-seeded legume pasture rejuvenation on greenhouse gases
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