28 research outputs found

    The search for transient astrophysical neutrino emission with IceCube-DeepCore

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    We present the results of a search for astrophysical sources of brief transient neutrino emission using IceCube and DeepCore data acquired between 2012 May 15 and 2013 April 30. While the search methods employed in this analysis are similar to those used in previous IceCube point source searches, the data set being examined consists of a sample of predominantly sub-TeV muon-neutrinos from the Northern Sky (-5 degrees < delta < 90 degrees) obtained through a novel event selection method. This search represents a first attempt by IceCube to identify astrophysical neutrino sources in this relatively unexplored energy range. The reconstructed direction and time of arrival of neutrino events are used to search for any significant self-correlation in the data set. The data revealed no significant source of transient neutrino emission. This result has been used to construct limits at timescales ranging from roughly 1 s to 10 days for generic soft-spectra transients. We also present limits on a specific model of neutrino emission from soft jets in core-collapse supernovae

    does participating in national and ethnic associations promote migrant integration a study with young first and second generation migrants

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    On arrival to a new country, migrants usually face language barriers, cultural barriers, discrimination, and other sources of unjust contextual conditions that lower their chances of a successful life (Handy and Greenspan, Nonprofit Volunt Sect Q 38:956–982, 2009). This scenario compromises their levels of well-being and supports a tendency toward social fragmentation in places of settlement (Garcia-Ramirez et al., Am J Community Psychol 47(1–2), 86–97, 2011). In response to this situation, migrants' engagement in civic life has been identified as an important element for developing both individual well-being and cohesive communities (Gilster, J Community Psychol 40(7), 769–784, 2012) (Stoll and Wong, Int Migr Rev 41(4), 880–908, 2007). Using a qualitative study, the present work explores the effects of activism on youth of sub-Saharan African origin, of the first and second generations, who are active in national and ethnic associations. The work aims to explore (1) through narratives the meaning that integration has for young migrants; (2) how integrated they feel; and (3) the role of the association, both national and ethnic, in the perception of integration of these young people

    A CMOS readout system for very large detector capacitances

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    In this contribution we present readout electronics for a liquid-argon calorimeter. It has been designed and optimized for operation at cryogenic temperatures and it is integrated in an n-well 2 ÎŒm CMOS technology. The chip contains 16 analog channels with switched-capacitor circuits for charge collection, storage, and amplification, and averaging and correlated double sampling circuits for noise reduction. Further components include a trigger generator, an analog multiplexer, digital control circuits for analog switching, and 50 ω cable drivers

    Neuroprotective and neurodegenerative effects of the chronic expression of tumor necrosis factor α in the nigrostriatal dopaminergic circuit of adult mice

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    Tumor necrosis factor (TNF)-α, a pro-inflammatory cytokine, has been implicated in both neuronal death and survival in Parkinson's disease (PD). The substantia nigra (SN), a CNS region affected in PD, is particularly susceptible to inflammatory insults and possesses the highest density of microglial cells, but the effects of inflammation and in particular TNF-α on neuronal survival in this region remains controversial. Using adenoviral vectors, the CRE/loxP system and hypomorphic mice, we achieved chronic expression of two levels of TNF-α in the SN of adult mice. Chronic low expression of TNF-α levels reduced the nigrostriatal neurodegeneration mediated by intrastriatal 6-hydroxydopamine administration. Protective effects of low TNF-α level could be mediated by TNF-R1, GDNF, and IGF-1 in the SN and SOD activity in the striatum (ST). On the contrary, chronic expression of high levels of TNF-α induced progressive neuronal loss (63% at 20 days and 75% at 100 days). This effect was accompanied by gliosis and an inflammatory infiltrate composed almost exclusively by monocytes/macrophages. The finding that chronic high TNF-α had a slow and progressive neurodegenerative effect in the SN provides an animal model of PD mediated by the chronic expression of a single cytokine. In addition, it supports the view that cytokines are not detrimental or beneficial by themselves, i.e., their level and time of expression among other factors can determine its final effect on CNS damage or protection. These data support the view that new anti-parkinsonian treatments based on anti-inflammatory therapies should consider these dual effects of cytokines on their design.
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