49 research outputs found

    Towards an Integrated Model for Functional and User Interface Requirements

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    VLA Observations of J1228+441, a Luminous Supernova Remnant in NGC 4449

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    The luminous, oxygen-rich supernova remnant, J1228+441, is located in the irregular galaxy NGC 4449 and has been observed at radio wavelengths for thirty years. An analysis of recent VLA observations of NGC 4449, combined with VLA archive data and previously published VLA and WSRT observations, yields light curves at 6 and 20 cm from 1972 to 2002. The light curves at all radio frequencies exhibit a marked decline in radio emission, confirming past findings. This paper presents and discusses the radio light curves and spectral index, alpha, variations from 1972 to 2002 where nu propto nu^(-alpha) and compares J1228+441 with other radio supernovae. The spectral index of J1228+441 appears to have steepened in the last five years at higher frequencies from alpha=0.64 +- 0.02 in 1996 to alpha=1.01 +- 0.02 in 2001-2002.Comment: aastex, 19 pages, 6 figures, to be published in A

    The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

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    The {\sc Majorana} collaboration is searching for neutrinoless double beta decay using 76^{76}Ge, which has been shown to have a number of advantages in terms of sensitivities and backgrounds. The observation of neutrinoless double-beta decay would show that lepton number is violated and that neutrinos are Majorana particles and would simultaneously provide information on neutrino mass. Attaining sensitivities for neutrino masses in the inverted hierarchy region, 155015 - 50 meV, will require large, tonne-scale detectors with extremely low backgrounds, at the level of \sim1 count/t-y or lower in the region of the signal. The {\sc Majorana} collaboration, with funding support from DOE Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the {\sc Demonstrator}, an array consisting of 40 kg of p-type point-contact high-purity germanium (HPGe) detectors, of which \sim30 kg will be enriched to 87% in 76^{76}Ge. The {\sc Demonstrator} is being constructed in a clean room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded shield approach with the inner portion consisting of ultra-clean Cu that is being electroformed and machined underground. The primary aim of the {\sc Demonstrator} is to show the feasibility of a future tonne-scale measurement in terms of backgrounds and scalability.Comment: Proceedings for the MEDEX 2013 Conferenc

    Acute myocardial infarction in a patient with hypofibrinogenemia: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Congenital fibrinogen deficiency is a rare coagulation disorder usually responsible for hemorrhagic diathesis. However, it can be associated with thrombosis and there have been limited reports of arterial thrombotic complications in these patients.</p> <p>Case presentation</p> <p>A 42-year-old Tunisian man with congenital hypofibrinogenemia and no cardiovascular risk factors presented with new onset prolonged angina pectoris. An electrocardiogram showed features of inferior acute myocardial infarction. His troponin levels had reached 17 ng/L. Laboratory findings confirmed hypofibrinogenemia and ruled out thrombophilia. Echocardiography was not useful in providing diagnostic elements but did show preserved left ventricular function. Coronary angiography was not performed and our patient did not receive any anticoagulant treatment due to the major risk of bleeding. Magnetic resonance imaging confirmed myocardial necrosis. Our patient was managed with aspirin, a beta-blocker, an angiotensin-converting enzyme inhibitor and statin medication. The treatment was well tolerated and no ischemic recurrence was detected.</p> <p>Conclusion</p> <p>Although coronary thrombosis is a rare event in patients with fibrinogen deficiency, this condition is of major interest in view of the difficulties observed in managing these patients.</p

    Status of the MAJORANA DEMONSTRATOR experiment

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    The MAJORANA DEMONSTRATOR neutrinoless double beta-decay experiment is currently under construction at the Sanford Underground Research Facility in South Dakota, USA. An overview and status of the experiment are given.Comment: 8 pages, proceeding from VII International Conference on Interconnections between Particle Physics and Cosmology (PPC 2013), submitted to AIP proceeding

    The Majorana experiment: an ultra-low background search for neutrinoless double-beta decay

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    The observation of neutrinoless double-beta decay would resolve the Majorana nature of the neutrino and could provide information on the absolute scale of the neutrino mass. The initial phase of the Majorana experiment, known as the Demonstrator, will house 40 kg of Ge in an ultra-low background shielded environment at the 4850' level of the Sanford Underground Laboratory in Lead, SD. The objective of the Demonstrator is to determine whether a future 1-tonne experiment can achieve a background goal of one count per tonne-year in a narrow region of interest around the 76Ge neutrinoless double-beta decay peak.Comment: Presentation for the Rutherford Centennial Conference on Nuclear Physic

    The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76

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    The observation of neutrinoless double-beta decay would determine whether the neutrino is a Majorana particle and provide information on the absolute scale of neutrino mass. The MAJORANA Collaboration is constructing the DEMONSTRATOR, an array of germanium detectors, to search for neutrinoless double-beta decay of 76-Ge. The DEMONSTRATOR will contain 40 kg of germanium; up to 30 kg will be enriched to 86% in 76-Ge. The DEMONSTRATOR will be deployed deep underground in an ultra-low-background shielded environment. Operation of the DEMONSTRATOR aims to determine whether a future tonne-scale germanium experiment can achieve a background goal of one count per tonne-year in a 4-keV region of interest around the 76-Ge neutrinoless double-beta decay Q-value of 2039 keV.Comment: Submitted to AIP Conference Proceedings, 19th Particles & Nuclei International Conference (PANIC 2011), Massachusetts Institute of Technology, Cambridge, MA, USA, July 24-29, 2011; 3 pages, 1 figur
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