197 research outputs found

    Acute variceal bleeding in a patient with idiopathic myelofibrosis successfully treated with endoscopic variceal band ligation and chemotherapy: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Idiopathic myelofibrosis is a chronic myeloproliferative disorder characterized by leukoerythroblastosis, massive splenomegaly, and increases in the reticular and collagen fibers in the bone marrow. Portal hypertension is observed in some patients with idiopathic myelofibrosis. Gastrointestinal hemorrhages, which are due mostly to the rupture of the esophageal varices, have been sporadically reported to be an infrequent complication of idiopathic myelofibrosis.</p> <p>Case presentation</p> <p>We report a case of a Japanese 63-year-old woman with myelofibrosis and variceal hemorrhage, with a background of concomitant portal and pulmonary hypertension. She was successfully treated through a combination of endoscopic variceal ligation and chemotherapy.</p> <p>Conclusion</p> <p>This is the first known report on the successful application of endoscopic variceal ligation and chemotherapy as the therapeutic procedure for an esophageal variceal hemorrhage in a patient with myelofibrosis.</p

    Constraints on neutrino oscillation parameters from the measurement of day-night solar neutrino fluxes at Super-Kamiokande

    Get PDF
    A search for day-night variations in the solar neutrino flux resulting from neutrino oscillations has been carried out using the 504 day sample of solar neutrino data obtained at Super-Kamiokande. The absence of a significant day-night variation has set an absolute flux independent exclusion region in the two neutrino oscillation parameter space.Comment: 11 pages, 3 figures, submitted to PRL, single-spacin

    Measurement of radon concentrations at Super-Kamiokande

    Full text link
    Radioactivity from radon is a major background for observing solar neutrinos at Super-Kamiokande. In this paper, we describe the measurement of radon concentrations at Super-Kamiokande, the method of radon reduction, and the radon monitoring system. The measurement shows that the current low-energy event rate between 5.0 MeV and 6.5 MeV implies a radon concentration in the Super-Kamiokande water of less than 1.4 mBq/m3^3.Comment: 11 pages, 4 figure

    Calibration of Super-Kamiokande Using an Electron Linac

    Get PDF
    In order to calibrate the Super-Kamiokande experiment for solar neutrino measurements, a linear accelerator (LINAC) for electrons was installed at the detector. LINAC data were taken at various positions in the detector volume, tracking the detector response in the variables relevant to solar neutrino analysis. In particular, the absolute energy scale is now known with less than 1 percent uncertainty.Comment: 24 pages, 16 figures, Submitted to NIM

    Measurement of a small atmospheric νμ/νe\nu_\mu/\nu_e ratio

    Full text link
    From an exposure of 25.5~kiloton-years of the Super-Kamiokande detector, 900 muon-like and 983 electron-like single-ring atmospheric neutrino interactions were detected with momentum pe>100p_e > 100 MeV/cc, pμ>200p_\mu > 200 MeV/cc, and with visible energy less than 1.33 GeV. Using a detailed Monte Carlo simulation, the ratio (μ/e)DATA/(μ/e)MC(\mu/e)_{DATA}/(\mu/e)_{MC} was measured to be 0.61±0.03(stat.)±0.05(sys.)0.61 \pm 0.03(stat.) \pm 0.05(sys.), consistent with previous results from the Kamiokande, IMB and Soudan-2 experiments, and smaller than expected from theoretical models of atmospheric neutrino production.Comment: 14 pages with 5 figure

    Observation of the east-west anisotropy of the atmospheric neutrino flux

    Get PDF
    The east-west anisotropy, caused by the deflection of primary cosmic rays in the Earth's magnetic field, is observed for the first time in the flux of atmospheric neutrinos. Using a 45 kt-year exposure of the Super-Kamiokande detector, 552 e-like and 633 mu-like horizontally-going events are selected in the momentum range between 400 and 3000 MeV/c. The azimuthal distribution of e-like and mu-like events agrees with the expectation from atmospheric neutrino flux calculations that account for the geomagnetic field, verifying that the geomagnetic field effects in the production of atmospheric neutrinos in the GeV energy range are well understood.Comment: 8 pages,3 figures revtex, submitted to PR

    Evidence for oscillation of atmospheric neutrinos

    Full text link
    We present an analysis of atmospheric neutrino data from a 33.0 kiloton-year (535-day) exposure of the Super-Kamiokande detector. The data exhibit a zenith angle dependent deficit of muon neutrinos which is inconsistent with expectations based on calculations of the atmospheric neutrino flux. Experimental biases and uncertainties in the prediction of neutrino fluxes and cross sections are unable to explain our observation. The data are consistent, however, with two-flavor nu_mu nu_tau oscillations with sin^2(2theta)>0.82 and 5x10^-4 < delta m^2 < 6x10^-3 eV^2 at 90% confidence level.Comment: 9 pages (two-column) with 4 figures. Small corrections to Eqn.4 and Fig.3. Final version to appear in PR
    corecore