2,995 research outputs found

    Dexamethasone in Treatment of Comorbid SARS-CoV-2 Patients Aged over 50 Years with Lung Injury over 50 %

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    Aim. An efficacy assessment of steroid therapy in SARS-CoV-2 patients aged over 50 years with lung damage over 50 % (grade 3–4).Materials and methods. A retrospective study of 158 SARS-CoV-2 patients hospitalised in April—June 2020 was conducted under the inclusion criteria: age over 50 years, chest computed tomography (CT) for COVID-19-asso-ciated pneumonia, C-reactive protein (CRP) >50 mg/L, anticoagulant therapy, no contraindications to steroids, no biologic therapy. Cohort 1 patients (n = 96) received dexamethasone 4–12 mg/day, cohort 2 (n = 62) — a standard non-dexamethasone therapy.Results. Dexamethasone treatment associated with a significant alleviation of COVID-19-associated pneumonia in CT score (p = 0.001), reduced fibrinogen (p = 0.001), a trend to CRP reduction by day 8–10 and lower demand for oxygen therapy, including ventilatory support (p = 0.001). Mortality rate was 19.8 and 75.8 % in cohorts 1 and 2, respectively (p = 0.001).Conclusion. Dexamethasone therapy 4–12 mg/day in SARS-CoV-2 patients aged 50+ years with grade 3–4 CT changes receiving LMWH from start of hospitalisation significantly improved CT scores and reduced mortality

    Measurement of J/ψγηcJ/\psi\to\gamma\eta_{\rm c} decay rate and ηc\eta_{\rm c} parameters at KEDR

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    Using the inclusive photon spectrum based on a data sample collected at the J/ψJ/\psi peak with the KEDR detector at the VEPP-4M e+ee^+e^- collider, we measured the rate of the radiative decay J/ψγηcJ/\psi\to\gamma\eta_{\rm c} as well as ηc\eta_{\rm c} mass and width. Taking into account an asymmetric photon lineshape we obtained Γγηc0=2.98±0.180.33+0.15\Gamma^0_{\gamma\eta_{\rm c}}=2.98\pm0.18 \phantom{|}^{+0.15}_{-0.33} keV, Mηc=2983.5±1.43.6+1.6M_{\eta_{\rm c}} = 2983.5 \pm 1.4 \phantom{|}^{+1.6}_{-3.6} MeV/c2c^2, Γηc=27.2±3.12.6+5.4\Gamma_{\eta_{\rm c}} = 27.2 \pm 3.1 \phantom{|}^{+5.4}_{-2.6} MeV.Comment: 6 pages, 3 figure

    Position resolution and particle identification with the ATLAS EM calorimeter

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    In the years between 2000 and 2002 several pre-series and series modules of the ATLAS EM barrel and end-cap calorimeter were exposed to electron, photon and pion beams. The performance of the calorimeter with respect to its finely segmented first sampling has been studied. The polar angle resolution has been found to be in the range 50-60 mrad/sqrt(E (GeV)). The neutral pion rejection has been measured to be about 3.5 for 90% photon selection efficiency at pT=50 GeV/c. Electron-pion separation studies have indicated that a pion fake rate of (0.07-0.5)% can be achieved while maintaining 90% electron identification efficiency for energies up to 40 GeV.Comment: 32 pages, 22 figures, to be published in NIM

    Measurement of J/psi to eta_c gamma at KEDR

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    We present a study of the inclusive photon spectra from 5.9 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of radiative decay J/psi to eta_c gamma, eta_c width and mass. Our preliminary results are: M(eta_c) = 2979.4+-1.5+-1.9 MeV, G(eta_c) = 27.8+-5.1+-3.3 MeV, B(J/psi to eta_c gamma) = (2.34+-0.15+-0.40)%.Comment: To be published in Proceedings of the PhiPsi09, Oct. 13-16, 2009, Beijing, Chin

    Measurement of B(J/psi->eta_c gamma) at KEDR

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    We present a study of the inclusive photon spectrum from 6.3 million J/psi decays collected with the KEDR detector at the VEPP-4M e+e- collider. We measure the branching fraction of the radiative decay J/psi -> eta_c gamma, eta_c width and mass. Taking into account an asymmetric photon line shape we obtain: M(eta_c) = (2978.1 +- 1.4 +- 2.0) MeV/c^2, Gamma(eta_c) = (43.5 +- 5.4 +- 15.8) MeV, B(J/psi->eta_c gamma) = (2.59 +- 0.16 +- 0.31)%$.Comment: 6 pages, 1 figure. To be published in the proceedings of the 4th International Workshop on Charm Physics (Charm2010), October 21-24, 2010, IHEP, Beijin

    Precise measurement of RudsR_{\text{uds}} and RR between 1.84 and 3.72 GeV at the KEDR detector

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    The present work continues a series of the KEDR measurements of the RR value that started in 2010 at the VEPP-4M e+ee^+e^- collider. By combining new data with our previous results in this energy range we measured the values of RudsR_{\text{uds}} and RR at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than 2.6%2.6\% at most of energy points with a systematic uncertainty of about 1.9%1.9\%. Together with the previous precise RR measurement at KEDR in the energy range 1.84-3.05 GeV, it constitutes the most detailed high-precision RR measurement near the charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial text overlap with arXiv:1510.0266

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations

    Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS

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    The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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