1,520 research outputs found

    Refractory hypoglycaemia in a dog infected with Trypanosoma congolense

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    A 20 kg German shepherd dog was presented to a French veterinary teaching hospital for seizures and hyperthermia. The dog had returned 1 month previously from a six-month stay in Senegal and sub-Saharan Africa. Biochemistry and haematology showed severe hypoglycaemia (0.12 g/L), anaemia and thrombocytopenia. Despite administration of large amounts of glucose (30 mL of 30% glucose IV and 10 mL of 70% sucrose by gavage tube hourly), 26 consecutive blood glucose measurements were below 0.25 g/L (except one). Routine cytological examination of blood smears revealed numerous free extracytoplasmic protozoa consistent with Trypanosoma congolense. PCR confirmed a Trypanosoma congolense forest-type infection. Treatment consisted of six injections of pentamidine at 48-hour intervals. Trypanosomes had disappeared from the blood smears four days following the first injection. Clinical improvement was correlated with the normalization of laboratory values. The infection relapsed twice and the dog was treated again; clinical signs and parasites disappeared and the dog was considered cured; however, 6 years after this incident, serological examination by ELISA T. congolense was positive. The status of this dog (infected or non-infected) remains unclear. Hypoglycaemia was the most notable clinical feature in this case. It was spectacular in its severity and in its refractory nature; glucose administration seemed only to feed the trypanosomes, indicating that treatment of hypoglycaemia may in fact have been detrimental

    Beam Energy Dependence of the Third Harmonic of Azimuthal Correlations in Au+Au Collisions at RHIC

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    We present results from a harmonic decomposition of two-particle azimuthal correlations measured with the STAR detector in Au+Au collisions for energies ranging from sNN=7.7\sqrt{s_{NN}}=7.7 GeV to 200 GeV. The third harmonic v32{2}=cos3(ϕ1ϕ2)v_3^2\{2\}=\langle \cos3(\phi_1-\phi_2)\rangle, where ϕ1ϕ2\phi_1-\phi_2 is the angular difference in azimuth, is studied as a function of the pseudorapidity difference between particle pairs Δη=η1η2\Delta\eta = \eta_1-\eta_2. Non-zero {\vthree} is directly related to the previously observed large-Δη\Delta\eta narrow-Δϕ\Delta\phi ridge correlations and has been shown in models to be sensitive to the existence of a low viscosity Quark Gluon Plasma (QGP) phase. For sufficiently central collisions, v32{2}v_3^2\{2\} persist down to an energy of 7.7 GeV suggesting that QGP may be created even in these low energy collisions. In peripheral collisions at these low energies however, v32{2}v_3^2\{2\} is consistent with zero. When scaled by pseudorapidity density of charged particle multiplicity per participating nucleon pair, v32{2}v_3^2\{2\} for central collisions shows a minimum near {\snn}=20=20 GeV.Comment: 7 pages, 4 figures, for submission to Phys. Rev. Let

    Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and ϕ\phi meson in Au+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We present high precision measurements of elliptic flow near midrapidity (y<1.0|y|<1.0) for multi-strange hadrons and ϕ\phi meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy sNN=\sqrt{s_{NN}}= 200 GeV. We observe that the transverse momentum dependence of ϕ\phi and Ω\Omega v2v_{2} is similar to that of π\pi and pp, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30%\% and 30-80%\% collision centrality. There is an indication of the breakdown of previously observed mass ordering between ϕ\phi and proton v2v_{2} at low transverse momentum in the 0-30%\% centrality range, possibly indicating late hadronic interactions affecting the proton v2v_{2}.Comment: 7 pages and 4 figures, Accepted for publication in Physical Review Letter

    Observation of charge asymmetry dependence of pion elliptic flow and the possible chiral magnetic wave in heavy-ion collisions

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    We present measurements of π\pi^- and π+\pi^+ elliptic flow, v2v_2, at midrapidity in Au+Au collisions at sNN=\sqrt{s_{_{\rm NN}}} = 200, 62.4, 39, 27, 19.6, 11.5 and 7.7 GeV, as a function of event-by-event charge asymmetry, AchA_{ch}, based on data from the STAR experiment at RHIC. We find that π\pi^- (π+\pi^+) elliptic flow linearly increases (decreases) with charge asymmetry for most centrality bins at sNN=27 GeV\sqrt{s_{_{\rm NN}}} = \text{27 GeV} and higher. At sNN=200 GeV\sqrt{s_{_{\rm NN}}} = \text{200 GeV}, the slope of the difference of v2v_2 between π\pi^- and π+\pi^+ as a function of AchA_{ch} exhibits a centrality dependence, which is qualitatively similar to calculations that incorporate a chiral magnetic wave effect. Similar centrality dependence is also observed at lower energies.Comment: 6 pages, 4 figure

    Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sqrt(s)= 7.7--62.4 GeV

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    Elliptic flow (v_2) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at sqrt{s_{NN}}= 7.7--62.4 GeV are presented for three centrality classes. The centrality dependence and the data at sqrt{s_{NN}}= 14.5 GeV are new. Except at the lowest beam energies we observe a similar relative v_2 baryon-meson splitting for all centrality classes which is in agreement within 15% with the number-of-constituent quark scaling. The larger v_2 for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with A Multiphase Transport Model and fit with a Blast Wave model.Comment: 14 pages, 12 figures, Phys. Rev. C, to be published. Data tables available at https://drupal.star.bnl.gov/STAR/publications/centrality-dependence-identified-particle-elliptic-flow-relativistic-heavy-ion-collisi

    J/ψ\rm{J}/\psi production at low transverse momentum in p+p and d+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV

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    We report on the measurement of J/ψ\rm{J}/\psi production in the dielectron channel at mid-rapidity (|y|<1) in p+p and d+Au collisions at sNN\sqrt{s_{NN}} = 200 GeV from the STAR experiment at the Relativistic Heavy Ion Collider. The transverse momentum pTp_{T} spectra in p+p for pTp_{T} < 4 GeV/c and d+Au collisions for pTp_{T} < 3 GeV/c are presented. These measurements extend the STAR coverage for J/ψ\rm{J}/\psi production in p+p collisions to low pTp_{T}. The from the measured J/ψ\rm{J}/\psi invariant cross section in p+p and d+Au collisions are evaluated and compared to similar measurements at other collision energies. The nuclear modification factor for J/ψ\rm{J}/\psi is extracted as a function of pTp_{T} and collision centrality in d+Au and compared to model calculations using the modified nuclear Parton Distribution Function and a final-state J/ψ\rm{J}/\psi nuclear absorption cross section

    Observation of D0D^0 meson nuclear modifications in Au+Au collisions at sNN\sqrt{s_{_{\mathrm{NN}}}} = 200 GeV

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    We report the first measurement of charmed-hadron (D0D^0) production via the hadronic decay channel (D0K+π+D^0\rightarrow K^- + \pi^+) in Au+Au collisions at sNN\sqrt{s_{_{\mathrm{NN}}}} = 200\,GeV with the STAR experiment. The charm production cross-section per nucleon-nucleon collision at mid-rapidity scales with the number of binary collisions, NbinN_{bin}, from pp+pp to central Au+Au collisions. The D0D^0 meson yields in central Au+Au collisions are strongly suppressed compared to those in pp+pp scaled by NbinN_{bin}, for transverse momenta pT>3p_{T}>3 GeV/cc, demonstrating significant energy loss of charm quarks in the hot and dense medium. An enhancement at intermediate pTp_{T} is also observed. Model calculations including strong charm-medium interactions and coalescence hadronization describe our measurements.Comment: 7 pages including author list, 4 figures, submit to PRL with revised versio
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