579 research outputs found

    Spatio-temporal patterns in the Hantavirus infection

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    We present a model of the infection of Hantavirus in deer mouse, Peromyscus maniculatus, based on biological observations of the system in the North American Southwest. The results of the analysis shed light on relevant observations of the biological system, such as the sporadical disappearance of the infection, and the existence of foci or ``refugia'' that perform as reservoirs of the virus when environmental conditions are less than optimal.Comment: 6 pages, 5 inlined figures, RevTeX 4 forma

    Tests of CPT Invariance at Neutrino Factories

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    We investigate possible tests of CPT invariance on the level of event rates at neutrino factories. We do not assume any specific model but phenomenological differences in the neutrino-antineutrino masses and mixing angles in a Lorentz invariance preserving context, such as it could be induced by physics beyond the Standard Model. We especially focus on the muon neutrino and antineutrino disappearance channels in order to obtain constraints on the neutrino-antineutrino mass and mixing angle differences; we found, for example, that the sensitivity ∣m3−mˉ3∣â‰Č1.9⋅10−4eV|m_3 - \bar{m}_3| \lesssim 1.9 \cdot 10^{-4} \mathrm{eV} could be achieved.Comment: 6 pages, 1 figure, RevTeX4. Final version to be published in Phys. Rev.

    Statistical Analysis of Different Muon-antineutrino->Electron-antineutrino Searches

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    A combined statistical analysis of the experimental results of the LSND and KARMEN \numubnueb oscillation search is presented. LSND has evidence for neutrino oscillations that is not confirmed by the KARMEN experiment. This joint analysis is based on the final likelihood results for both data sets. A frequentist approach is applied to deduce confidence regions. At a combined confidence level of 36%, there is no area of oscillation parameters compatible with both experiments. For the complementary confidence of 1-0.36=64%, there are two well defined regions of oscillation parameters (sin^2(2th),Dm^2) compatible with both experiments.Comment: 25 pages, including 10 figures, submitted to Phys. Rev.

    Continuity of the Middle Stone Age into the Holocene

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    The African Middle Stone Age (MSA, typically considered to span ca. 300–30 thousand years ago [ka]), represents our species’ first and longest lasting cultural phase. Although the MSA to Later Stone Age (LSA) transition is known to have had a degree of spatial and temporal variability, recent studies have implied that in some regions, the MSA persisted well beyond 30 ka. Here we report two new sites in Senegal that date the end of the MSA to around 11 ka, the youngest yet documented MSA in Africa. This shows that this cultural phase persisted into the Holocene. These results highlight significant spatial and temporal cultural variability in the African Late Pleistocene, consistent with genomic and palaeoanthropological hypotheses that significant, long-standing inter-group cultural differences shaped the later stages of human evolution in Africa

    Motivational approaches to intellectual vice

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    Despite the now considerable literature on intellectual virtue, there remains relatively little philosophical discussion of intellectual vice. What discussion there is has been shaped by a powerful assumption—that, just as intellectual virtue requires that we are motivated by epistemic goods, intellectual vice requires that we aren't. In this paper, I demonstrate that this assumption is false: motivational approaches cannot explain a range of intuitive cases of intellectual vice. The popularity of the assumption is accounted for by its being a manifestation of a more general understanding of vice as an inversion or mirror image of virtue. I call this the inversion thesis, and argue that the failure of the motivational approach to vice exposes its limitations. I conclude by suggesting that recognizing these limitations can help to encourage philosophical interest in intellectual vice

    Circadian rhythm of urinary pH in man with and without chronic antacid administration

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    In normal human volunteers, when urinary pH was plotted versus time, the circadian sine-wave type curve was not altered by chronic administration of a commercially available suspension containing a mixture of magnesium and aluminum hydroxides, although the antacid perturbed the entire curve in a more alkaline direction. A single dose of the antacid had little effect on urinary pH. There was a highly significant linear relationship between the change in hydrogen ion concentration during chronic antacid treatment and the initial control urinary hydrogen ion concentration, but there was no significant correlation between change in urinary pH and initial control urinary pH as has been previously reported. The above results were based on the evaluation of the hydrogen ion concentrations of 1562 separate urine samples collected from 24 normal subjects in a three treatment crossover study. It is recommended that: (1) research studies involving drug-drug interactions with antacids be designed to consider the effect of the antacid on the circadian rhythm of urinary pH, and (2) pH values not be averaged as commonly reported in the literature, but rather the pH values be converted to hydrogen ion concentrations before statistical analysis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46636/1/228_2004_Article_BF00561060.pd

    Star Formation and Dynamics in the Galactic Centre

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    The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201

    An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics

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    For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types

    Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

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    This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio
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