564 research outputs found

    Mass hierarchy discrimination with atmospheric neutrinos in large volume ice/water Cherenkov detectors

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    Large mass ice/water Cherenkov experiments, optimized to detect low energy (1-20 GeV) atmospheric neutrinos, have the potential to discriminate between normal and inverted neutrino mass hierarchies. The sensitivity depends on several model and detector parameters, such as the neutrino flux profile and normalization, the Earth density profile, the oscillation parameter uncertainties, and the detector effective mass and resolution. A proper evaluation of the mass hierarchy discrimination power requires a robust statistical approach. In this work, the Toy Monte Carlo, based on an extended unbinned likelihood ratio test statistic, was used. The effect of each model and detector parameter, as well as the required detector exposure, was then studied. While uncertainties on the Earth density and atmospheric neutrino flux profiles were found to have a minor impact on the mass hierarchy discrimination, the flux normalization, as well as some of the oscillation parameter (\Delta m^2_{31}, \theta_{13}, \theta_{23}, and \delta_{CP}) uncertainties and correlations resulted critical. Finally, the minimum required detector exposure, the optimization of the low energy threshold, and the detector resolutions were also investigated.Comment: 23 pages, 16 figure

    A case report of successful endovascular treatment of "sentinel bleeding" in patient with adverse anatomy

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    Surgical treatment of pancreatic cancer, has a high risk of postoperative complications (up to 30-70%) due to its difficulty, one of such undesirable outcomes is bleeding (up to 10% of all post PDE complication. Since 1991, a non-fatal gastrointestinal bleeding or bleeding through drainage that follows PDE, is called - “sentinel bleeding”; and it is a predictor of further massive fatal bleedin

    A novel tri-unsaturated highly branched isoprenoid (HBI) alkene from the marine diatom Navicula salinicola

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    A novel tri-unsaturated C25 highly branched isoprenoid (HBI) alkene has been identified in a laboratory culture of the diatom Navicula salinicola and its structure determined using a combination of NMR spectroscopy and gas chromatography–mass spectrometry (GC–MS). This represents the first report of a C25 HBI in a marine diatom from the Navicula genus, although a different tri-unsaturated C25 HBI has been reported previously in the freshwater species N. sclesvicensis and unspecified HBIs have been identified in the brackish N. phyllepta. The newly characterised HBI contains a relatively unusual conjugated diene sub-unit, a structural feature only previously reported in some HBIs biosynthesised by a further marine diatom, Haslea ostrearia

    Kulikovskiyia gen. nov. (Bacillariophyceae) from the lateritic rock pools of the Western Ghats, India and from Hainan Province, China

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    A new triundulate naviculoid diatom genus is described from the Western Ghats of Peninsular India and Hainan Province, China. The new taxon, Kulikovskiyia gen. nov. has robust conical spines along its margin and at the apices and the external valve face has longitudinally‐oriented siliceous slat system extending the length of the valve. The external distal raphe ends bifurcate and terminates on the valve face. There appear to be superficial similarities between this Asian genus and species and Playaensis, a genus comprised of two species found only in the western USA. The systematic position of Kulikovskiyia is discussed, and other than noting its similarities to other biraphid naviculoid diatoms due to symmetry features and the position of the raphe, we are uncertain about its systematic placement at finer levels of classification.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/153713/1/pre12400_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/153713/2/pre12400.pd

    Sellaphora balashovae (Bacillariophyta), a new species from siberian mountain lake frolikha (Baikal region), Russia

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    © 2018 Magnolia Press. A new species, Sellaphora balashovae sp. nov., from Lake Frolikha is described based on light (LM) and scanning electron microscopy (SEM). The systematic position of this new species is determined based on molecular data. This species is placed in the genus Sellaphora based on chloroplast morphology, areolae covered by external hymenes, and uniseriate striae that are typical for the genus. Molecular data support this taxonomic assignment, and the new species is part of a monophyletic group with some other members of the genus Sellaphora. The new species is distinguishable from other Sellaphora species by its small size, valve shape, striae and areolae densities, striae orientation and distinctly large areolae bordering the sternum

    Search for muon-neutrino emission from GeV and TeV gamma-ray flaring blazars using five years of data of the ANTARES telescope

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    The ANTARES telescope is well-suited for detecting astrophysical transient neutrino sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background due to atmospheric particles can be drastically reduced, and the point-source sensitivity improved, by selecting a narrow time window around possible neutrino production periods. Blazars, being radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the very high-energy cosmic rays. Neutrinos and gamma rays may be produced in hadronic interactions with the surrounding medium. Moreover, blazars generally show high time variability in their light curves at different wavelengths and on various time scales. This paper presents a time-dependent analysis applied to a selection of flaring gamma-ray blazars observed by the FERMI/LAT experiment and by TeV Cherenkov telescopes using five years of ANTARES data taken from 2008 to 2012. The results are compatible with fluctuations of the background. Upper limits on the neutrino fluence have been produced and compared to the measured gamma-ray spectral energy distribution.Comment: 27 pages, 16 figure

    Measurement of the atmospheric muon depth intensity relation with the NEMO Phase-2 tower

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    The results of the analysis of the data collected with the NEMO Phase-2 tower, deployed at 3500 m depth about 80 km off-shore Capo Passero (Italy), are presented. Cherenkov photons detected with the photomultipliers tubes were used to reconstruct the tracks of atmospheric muons. Their zenith-angle distribution was measured and the results compared with Monte Carlo simulations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is also included. The associated depth intensity relation was evaluated and compared with previous measurements and theoretical predictions. With the present analysis, the muon depth intensity relation has been measured up to 13 km of water equivalent.Comment: submitted to Astroparticle Physic

    The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)

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    The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics
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