2,558 research outputs found

    Prognosis in patients with myocardial infarction with ST-elevation depending on the timing of interventional revascularization

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    Проверена е прогнозата (болничния и следболничния леталитет до края на 6-ия месец) при 300 болни (212 мъже и 88 жени) с първи миокарден инфаркт със ST- елевация (STEMI) на средна възраст 62.9 год. в зависимост от срока на извършената първична коронарна интервенция (PCI) след началото на симптомите. В зависимост от срока на извършената РСІ болните са разделени на 4 групи: до 3-ия, до 6-ия, до 12-ия и до 24-ия час след началото на инфаркта. Болничният леталитет за всички болни е 6.3%, a до края на 6-ия месец - 13.3%, еднакъв при І-ва и ІІ-ра група и достоверно по-малък, отколкото при ІІІ-та и ІV-та група, по-голям при жените, при болните над 65 г., с ФИ <35.0% и с тромботична оклузия на LM и LAD.The prognosis (in-hospital and post-hospitalization lethality by the end of the 6th moth) of 300 patients (212 men and 88 women) with a first myocardial infarction with ST-elevation (STEMI) at an average age of 62.9 years was studied depending on the timing of the conducted primary coronary intervention (PCI) after the onset of symptoms. Depending on the timing of the conducted PCI, the patients were divided into 4 groups: by the 3rd, 6th, 12th, and 24th hour after the onset of the infarction. The patients` in-hospital lethality was 6.3%, and that by the end of the 6th month - 13.3%. It was the same for groups I and II and significantly lower than in groups III and IV; higher in women, in patients over 65 years of age, with ejection fraction (EF) <35.0% and with thrombotic occlusion of LM and LAD

    Phonon pressure coefficients and deformation potentials of wurtzite AlN determined by uniaxial pressure-dependent Raman measurements

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    © 2014 American Physical Society. We studied bulk crystals of wurtzite AlN by means of uniaxial pressure-dependent Raman measurements. As a result, we derive the phonon pressure coefficients and deformation potentials for all zone center optical phonon modes. For the A1 and E1 modes, we further experimentally determined the uniaxial pressure dependence of their longitudinal optical-transverse optical (LO-TO) splittings. Our experimental approach delivers new insight into the large variance among previously reported phonon deformation potentials, which are predominantly based on heteroepitaxial growth of AlN and the ball-on-ring technique. Additionally, the measured phonon pressure coefficients are compared to their theoretical counterparts obtained by density functional theory implemented in the siesta package. Generally, we observe a good agreement between the calculated and measured phonon pressure coefficients but some particular Raman modes exhibit significant discrepancies similar to the case of wurtzite GaN and ZnO, clearly motivating the presented uniaxial pressure-dependent Raman measurements on bulk AlN crystals

    \b{eta}-delayed three-proton decay of 31Ar

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    The beta decay of 31Ar, produced by fragmentation of a 36Ar beam at 880 MeV/nucleon, was investigated. Identified ions of 31Ar were stopped in a gaseous time projection chamber with optical readout allowing to record decay events with emission of protons. In addition to \b{eta}-delayed emission of one and two protons we have clearly observed the beta-delayed three-proton branch. The branching ratio for this channel in 31Ar is found to be 0.07(2)%.Comment: 5 pages, 3 figures, submitted to Physical Rev.

    Search for the QCD critical point in nuclear collisions at the CERN SPS

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    Pion production in nuclear collisions at the SPS is investigated with the aim to search, in a restricted domain of the phase diagram, for power-laws in the behavior of correlations which are compatible with critical QCD. We have analyzed interactions of nuclei of different size (p+p, C+C, Si+Si, Pb+Pb) at 158AA GeV adopting, as appropriate observables, scaled factorial moments in a search for intermittent fluctuations in transverse dimensions. The analysis is performed for π+π\pi^+\pi^- pairs with invariant mass very close to the two-pion threshold. In this sector one may capture critical fluctuations of the sigma component in a hadronic medium, even if the σ\sigma-meson has no well defined vacuum state. It turns out that for the Pb+Pb system the proposed analysis technique cannot be applied without entering the invariant mass region with strong Coulomb correlations. As a result the treatment becomes inconclusive in this case. Our results for the other systems indicate the presence of power-law fluctuations in the freeze-out state of Si+Si approaching in size the prediction of critical QCD.Comment: 31 pages, 11 figure

    Multiplicity fluctuations in nuclear collisions at 158 A GeV

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    System size dependence of multiplicity fluctuations of charged particles produced in nuclear collisions at 158 A GeV was studied in the NA49 CERN experiment. Results indicate a non-monotonic dependence of the scaled variance of the multiplicity distribution with a maximum for semi-peripheral Pb+Pb interactions with number of projectile participants of about 35. This effect is not observed in a string-hadronic model of nuclear collision HIJING.Comment: Presented at "Focus on Multiplicity", 17-19 of June, Bari, Ital

    Observation of an Exotic S = -2, Q = -2 Baryon Resonance in Proton-Proton Collisions at the CERN SPS

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    Results of resonance searches in the Xi- pi-, Xi- pi+, antiXi+ pi- and antiXi+ pi+ invariant mass spectra in proton-proton collisions at sqrt{s}=17.2 GeV are presented. Evidence is shown for the existence of a narrow Xi- pi- baryon resonance with mass of 1.862+/-0.002 GeV/c^2 and width below the detector resolution of about 0.018 GeV/c^2. The significance is estimated to be 4.0 sigma. This state is a candidate for the hypothetical exotic Xi_(3/2)^-- baryon with S = -2, I = 3/2 and a quark content of (d s d s ubar). At the same mass a peak is observed in the Xi- pi+ spectrum which is a candidate for the Xi_(3/2)^0 member of this isospin quartet with a quark content of (d s u s dbar). The corresponding antibaryon spectra also show enhancements at the same invariant mass.Comment: 5 pages, 3 figure

    Transverse Momentum Fluctuations in Nuclear Collisions at 158 AGeV

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    Results are presented on event-by-event fluctuations in transverse momentum of charged particles, produced at forward rapidities in p+p, C+C, Si+Si and Pb+Pb collisions at 158 AGeV. Three different characteristics are discussed: the average transverse momentum of the event, the Phi_pT fluctuation measure and two-particle transverse momentum correlations. In the kinematic region explored, the dynamical fluctuations are found to be small. However, a significant system size dependence of Phi_pT is observed, with the largest value measured in peripheral Pb+Pb interactions. The data are compared with predictions of several models.Comment: will be submitted to Phys. Rev.

    Omega and Antiomega production in central Pb+Pb collisions at 40 and 158 AGeV

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    Results are presented on Omega production in central Pb+Pb collisions at 40 and 158 AGeV beam energy. Given are transverse-mass spectra, rapidity distributions, and total yields for the sum Omega+Antiomega at 40 AGeV and for Omega and Antiomega separately at 158 AGeV. The yields are strongly under-predicted by the string-hadronic UrQMD model and are in better agreement with predictions from a hadron gas models.Comment: 5 papes, 4 figures, 1 table, updated figure 4 and table 1. Final version, including some editorial changes, as published in PR

    Lambda production in central Pb+Pb collisions at CERN-SPS energies

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    In this paper we present recent results from the NA49 experiment for Λ\Lambda and Λˉ\bar{\Lambda} hyperons produced in central Pb+Pb collisions at 40, 80 and 158 A\cdotGeV. Transverse mass spectra and rapidity distributions for Λ\Lambda are shown for all three energies. The shape of the rapidity distribution becomes flatter with increasing beam energy. The multiplicities at mid-rapidity as well as the total yields are studied as a function of collision energy including AGS measurements. The ratio Λ/π\Lambda/\pi at mid-rapidity and in 4π\pi has a maximum around 40 A\cdotGeV. In addition, Λˉ\bar{\Lambda} rapidity distributions have been measured at 40 and 80 A\cdotGeV, which allows to study the Λˉ\bar{\Lambda}/Λ\Lambda ratio.Comment: SQM proceedings. J. Phys. G: Nucl. Part. Phys.: submitte

    Energy dependence of particle ratio fluctuations in central Pb+Pb collisions from sNN=\sqrt{s_{_{NN}}} =~6.3 to 17.3 GeV

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    We present measurements of the energy dependence of event-by-event fluctuations in the K/pi and (p + \bar{p})/pi multiplicity ratios in heavy ion collisions at the CERN SPS. The particle ratio fluctuations were obtained for central Pb+Pb collisions at five collision energies, \sqrt{s_{_{NN}}}, between 6.3 and 17.3 GeV. After accounting for the effects of finite-number statistics and detector resolution, we extract the strength of non-statistical fluctuations at each energy. For the K/pi ratio, larger fluctuations than expected for independent particle production are found at all collision energies. The fluctuations in the (p + \bar{p})/pi ratio are smaller than expectations from independent particle production, indicating correlated pion and proton production from resonance decays. For both ratios, the deviation from purely statistical fluctuations shows an increase towards lower collision energies. The results are compared to transport model calculations, which fail to describe the energy dependence of the K/pi ratio fluctuations.Comment: 11 pages, 10 figures, update to published versio
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