533 research outputs found

    Marburg hemorrhagic fever in Durba and Watsa, Democratic Republic of the Congo: clinical documentation, features of illness, and treatment

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    The objective of the present study was to describe day of onset and duration of symptoms of Marburg hemorrhagic fever (MHF), to summarize the treatments applied, and to assess the quality of clinical documentation. Surveillance and clinical records of 77 patients with MHF cases were reviewed. Initial symptoms included fever, headache, general pain, nausea, vomiting, and anorexia (median day of onset, day 1-2), followed by hemorrhagic manifestations (day 5-8+), and terminal symptoms included confusion, agitation, coma, anuria, and shock. Treatment in isolation wards was acceptable, but the quality of clinical documentation was unsatisfactory. Improved clinical documentation is necessary for a basic evaluation of supportive treatment

    The Fecal Position: Tracking Progressive DNA Repeat Expansion via Stool DNA Extraction

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    Friedreich Ataxia is a progressive DNA repeat expansion disease. Examining DNA repeat expansion in mouse models require sacrificing the mouse and taking samples of organs. The obvious non-lethal targets, such as ears, tails, and blood do not have levels of repeat expansion comparable to internal organs. However, recent publications suggest that stool may be a suitable non-lethal candidate for tracking repeat expansion over time. Stool DNA may allow researchers to monitor the effect of interventions aimed at slowing DNA repeat expansion over time without harming the mouse. A commercial kit was first used to extract DNA from feces without success. Stool DNA was isolated using a “home-made” approach based on older methodology. The presence of mouse DNA within the bacterial background DNA was first confirmed using mouse beta actin PCR primers. This was followed by two rounds of nested PCR with PCR primers specific for the expanded GAA●TTC tract in the frataxin transgene carried by the Friedrich Ataxia model mouse. Stool DNA poses a unique challenge due to the degradation of its components, high lipid content, and high level of bacterial DNA contamination. However, this method of DNA extraction was nearly 100% successful. We compare ear samples taken at three weeks to stool taken later to prove the utility of this approach for repeat expansion models

    Clinical Manifestations and Case Management of Ebola Haemorrhagic Fever caused by a newly identified virus strain, Bundibugyo, Uganda, 2007-2008

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    A confirmed Ebola haemorrhagic fever (EHF) outbreak in Bundibugyo, Uganda, November 2007-February 2008, was caused by a putative new species (Bundibugyo ebolavirus). It included 93 putative cases, 56 laboratory-confirmed cases, and 37 deaths (CFR = 25%). Study objectives are to describe clinical manifestations and case management for 26 hospitalised laboratory-confirmed EHF patients. Clinical findings are congruous with previously reported EHF infections. The most frequently experienced symptoms were non-bloody diarrhoea (81%), severe headache (81%), and asthenia (77%). Seven patients reported or were observed with haemorrhagic symptoms, six of whom died. Ebola care remains difficult due to the resource-poor setting of outbreaks and the infection-control procedures required. However, quality data collection is essential to evaluate case definitions and therapeutic interventions, and needs improvement in future epidemics. Organizations usually involved in EHF case management have a particular responsibility in this respect

    Detection of Gamma-Ray Emission from the Starburst Galaxies M82 and NGC 253 with the Large Area Telescope on Fermi

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    We report the detection of high-energy gamma-ray emission from two starburst galaxies using data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from sources positionally coincident with locations of the starburst galaxies M82 and NGC 253. The total fluxes of the sources are consistent with gamma-ray emission originating from the interaction of cosmic rays with local interstellar gas and radiation fields and constitute evidence for a link between massive star formation and gamma-ray emission in star-forming galaxies.Comment: Submitted to ApJ Letter

    Fermi Gamma-ray Imaging of a Radio Galaxy

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    The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating from the giant radio lobes of the radio galaxy Centaurus A. The resolved gamma-ray image shows the lobes clearly separated from the central active source. In contrast to all other active galaxies detected so far in high-energy gamma-rays, the lobe flux constitutes a considerable portion (>1/2) of the total source emission. The gamma-ray emission from the lobes is interpreted as inverse Compton scattered relic radiation from the cosmic microwave background (CMB), with additional contribution at higher energies from the infrared-to-optical extragalactic background light (EBL). These measurements provide gamma-ray constraints on the magnetic field and particle energy content in radio galaxy lobes, and a promising method to probe the cosmic relic photon fields.Comment: 27 pages, includes Supplementary Online Material; corresponding authors: C.C. Cheung, Y. Fukazawa, J. Knodlseder, L. Stawar

    Using L/E Oscillation Probability Distributions

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    This paper explores the use of L/EL/E oscillation probability distributions to compare experimental measurements and to evaluate oscillation models. In this case, LL is the distance of neutrino travel and EE is a measure of the interacting neutrino's energy. While comparisons using allowed and excluded regions for oscillation model parameters are likely the only rigorous method for these comparisons, the L/EL/E distributions are shown to give qualitative information on the agreement of an experiment's data with a simple two-neutrino oscillation model. In more detail, this paper also outlines how the L/EL/E distributions can be best calculated and used for model comparisons. Specifically, the paper presents the L/EL/E data points for the final MiniBooNE data samples and, in the Appendix, explains and corrects the mistaken analysis published by the ICARUS collaboration

    Improved Search for νˉμνˉe\bar ν_μ\rightarrow \bar ν_e Oscillations in the MiniBooNE Experiment

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    Submitted to PRL. Further information provided in arXiv:1207.4809Submitted to PRL. Further information provided in arXiv:1207.4809The MiniBooNE experiment at Fermilab reports results from an analysis of νˉe\bar \nu_e appearance data from 11.27×102011.27 \times 10^{20} protons on target in antineutrino mode, an increase of approximately a factor of two over the previously reported results. An event excess of 78.4±28.578.4 \pm 28.5 events (2.8σ2.8 \sigma) is observed in the energy range 200<EνQE<1250200<E_\nu^{QE}<1250 MeV. If interpreted in a two-neutrino oscillation model, νˉμνˉe\bar{\nu}_{\mu}\rightarrow\bar{\nu}_e, the best oscillation fit to the excess has a probability of 66% while the background-only fit has a χ2\chi^2-probability of 0.5% relative to the best fit. The data are consistent with antineutrino oscillations in the 0.01<Δm2<1.00.01 < \Delta m^2 < 1.0 eV2^2 range and have some overlap with the evidence for antineutrino oscillations from the Liquid Scintillator Neutrino Detector (LSND). All of the major backgrounds are constrained by in-situ event measurements so non-oscillation explanations would need to invoke new anomalous background processes. The neutrino mode running also shows an excess at low energy of 162.0±47.8162.0 \pm 47.8 events (3.4σ3.4 \sigma) but the energy distribution of the excess is marginally compatible with a simple two neutrino oscillation formalism. Expanded models with several sterile neutrinos can reduce the incompatibility by allowing for CP violating effects between neutrino and antineutrino oscillations

    Search for gamma-ray emission from magnetars with the Fermi Large Area Telescope

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    We report on the search for 0.1-10 GeV emission from magnetars in 17 months of Fermi Large Area Telescope (LAT) observations. No significant evidence for gamma-ray emission from any of the currently-known magnetars is found. The most stringent upper limits to date on their persistent emission in the Fermi-LAT energy range are estimated between ~10^{-12}-10^{-10} erg/s/cm2, depending on the source. We also searched for gamma-ray pulsations and possible outbursts, also with no significant detection. The upper limits derived support the presence of a cut-off at an energy below a few MeV in the persistent emission of magnetars. They also show the likely need for a revision of current models of outer gap emission from strongly magnetized pulsars, which, in some realizations, predict detectable GeV emission from magnetars at flux levels exceeding the upper limits identified here using the Fermi-LAT observations.Comment: ApJ Letters in press; Corresponding authors: Caliandro G. A., Hadasch D., Rea N., Burnett

    A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279

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    It is widely accepted that strong and variable radiation detected over all accessible energy bands in a number of active galaxies arises from a relativistic, Doppler-boosted jet pointing close to our line of sight. The size of the emitting zone and the location of this region relative to the central supermassive black hole are, however, poorly known, with estimates ranging from light-hours to a light-year or more. Here we report the coincidence of a gamma-ray flare with a dramatic change of optical polarization angle. This provides evidence for co-spatiality of optical and gamma-ray emission regions and indicates a highly ordered jet magnetic field. The results also require a non-axisymmetric structure of the emission zone, implying a curved trajectory for the emitting material within the jet, with the dissipation region located at a considerable distance from the black hole, at about 10^5 gravitational radii.Comment: Published in Nature issued on 18 February 2010. Corresponding authors: Masaaki Hayashida and Greg Madejsk
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