870 research outputs found

    Human rights in public health: Deepening engagement at a critical time

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    This year marks the 70th anniversary of both the birth of human rights law through the Universal Declaration of Human Rights (UDHR) and the birth of global health governance through the World Health Organization (WHO). Over the past 70 years, human rights have developed under international law as a basis for public health, providing a foundation for human rights realization through public health practice. Yet this “health and human rights” movement now faces unprecedented threats amidst a shift toward populism—with the populist radical right in ascendance in the United States and in countries throughout the world

    Entropy and Spin Susceptibility of s-wave Type-II Superconductors near Hc2H_{c2}

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    A theoretical study is performed on the entropy SsS_{\rm s} and the spin susceptibility χs\chi_{\rm s} near the upper critical field Hc2H_{c2} of s-wave type-II superconductors with arbitrary impurity concentrations. The changes of these quantities through Hc2H_{c2} may be expressed as [Ss(T,B)−Ss(T,0)]/[Sn(T)−Ss(T,0)]=1−αS(1−B/Hc2)≈(B/Hc2)αS[S_{\rm s}(T,B)-S_{\rm s}(T,0)]/[S_{\rm n}(T)-S_{\rm s}(T,0)]=1-\alpha_{S}(1-B/H_{c2})\approx (B/H_{c2})^{\alpha_{S}}, for example, where BB is the average flux density and SnS_{\rm n} denotes entropy in the normal state. It is found that the slopes αS\alpha_{S} and αχ\alpha_{\chi} at T=0 are identical, connected directly with the zero-energy density of states, and vary from 1.72 in the dirty limit to 0.5∌0.60.5\sim 0.6 in the clean limit. This mean-free-path dependence of αS\alpha_{S} and αχ\alpha_{\chi} at T=0 is quantitatively the same as that of the slope αρ(T=0)\alpha_{\rho}(T=0) for the flux-flow resistivity studied previously. The result suggests that Ss(B)S_{\rm s}(B) and χs(B)\chi_{\rm s}(B) near T=0 are convex downward (upward) in the dirty (clean) limit, deviating substantially from the linear behavior ∝B/Hc2\propto B/H_{c2}. The specific-heat jump at Hc2H_{c2} also shows fairly large mean-free-path dependence.Comment: 8 pages, 5 figure

    The Role of Cutaneous Receptors in the Menton Tap Silent Period

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    The neuromuscular mechanisms of the electromyographic silent period are poorly understood but clinically significant. Our purpose was to isolate the contribution of cutaneous afferents from the chin to the latency and the duration of the EMG silent period. Under the conditions of our experiment, the afferents of the mental nerve have no observable influence on the latency or the duration of the silent period educed by a menton tap.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66492/2/10.1177_00220345790580011001.pd

    Low Energy Analyzing Powers in Pion-Proton Elastic Scattering

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    Analyzing powers of pion-proton elastic scattering have been measured at PSI with the Low Energy Pion Spectrometer LEPS as well as a novel polarized scintillator target. Angular distributions between 40 and 120 deg (c.m.) were taken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic energy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering. These new measurements constitute a substantial extension of the polarization data base at low energies. Predictions from phase shift analyses are compared with the experimental results, and deviations are observed at low energies.Comment: 15 pages, 4 figure

    A fossil winonaite-like meteorite in Ordovician limestone: A piece of the impactor that broke up the L-chondrite parent body?

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    AbstractAbout a quarter of all meteorites falling on Earth today originate from the breakup of the L-chondrite parent body ∌470 Ma ago, the largest documented breakup in the asteroid belt in the past ∌3 Ga. A window into the flux of meteorites to Earth shortly after this event comes from the recovery of about 100 fossil L chondrites (1–21 cm in diameter) in a quarry of mid-Ordovician limestone in southern Sweden. Here we report on the first non-L-chondritic meteorite from the quarry, an 8 cm large winonaite-related meteorite of a type not known among present-day meteorite falls and finds. The noble gas data for relict spinels recovered from the meteorite show that it may be a remnant of the body that hit and broke up the L-chondrite parent body, creating one of the major asteroid families in the asteroid belt. After two decades of systematic recovery of fossil meteorites and relict extraterrestrial spinel grains from marine limestone, it appears that the meteorite flux to Earth in the mid-Ordovician was very different from that of today

    Exclusive Measurements of pd→3Heππpd\to ^3He \pi\pi : the ABCABC Effect Revisited

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    Exclusive measurements of the reactions pd→pd\to 3Heπ+π−^3He \pi^+ \pi^- and pd→pd\to 3Heπ0π0^3He \pi^0\pi^0 have been carried out at Tp=0.895T_p=0.895 GeV at the CELSIUS storage ring using the WASA detector. The π+π−\pi^+\pi^- channel evidences a pronounced enhancement at low invariant ππ\pi\pi masses - as anticipated from previous inclusive measurements of the ABC effect. This enhancement is seen to be even much larger in the isoscalar π0π0\pi^0\pi^0 channel. The differential distributions prove this enhancement to be of scalar-isoscalar nature. ΔΔ\Delta\Delta calculations give a good description of the data, if a boundstate condition is imposed for the intermediate ΔΔ\Delta\Delta system.Comment: extended version, 8 pages, 7 figures, theoretical model calculations adde

    Baryon polarization in low-energy unpolarized meson-baryon scattering

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    We compute the polarization of the final-state baryon, in its rest frame, in low-energy meson--baryon scattering with unpolarized initial state, in Unitarized BChPT. Free parameters are determined by fitting total and differential cross-section data (and spin-asymmetry or polarization data if available) for pK−pK^-, pK+pK^+ and pπ+p\pi^+ scattering. We also compare our results with those of leading-order BChPT

    Spallation reactions. A successful interplay between modeling and applications

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    The spallation reactions are a type of nuclear reaction which occur in space by interaction of the cosmic rays with interstellar bodies. The first spallation reactions induced with an accelerator took place in 1947 at the Berkeley cyclotron (University of California) with 200 MeV deuterons and 400 MeV alpha beams. They highlighted the multiple emission of neutrons and charged particles and the production of a large number of residual nuclei far different from the target nuclei. The same year R. Serber describes the reaction in two steps: a first and fast one with high-energy particle emission leading to an excited remnant nucleus, and a second one, much slower, the de-excitation of the remnant. In 2010 IAEA organized a worskhop to present the results of the most widely used spallation codes within a benchmark of spallation models. If one of the goals was to understand the deficiencies, if any, in each code, one remarkable outcome points out the overall high-quality level of some models and so the great improvements achieved since Serber. Particle transport codes can then rely on such spallation models to treat the reactions between a light particle and an atomic nucleus with energies spanning from few tens of MeV up to some GeV. An overview of the spallation reactions modeling is presented in order to point out the incomparable contribution of models based on basic physics to numerous applications where such reactions occur. Validations or benchmarks, which are necessary steps in the improvement process, are also addressed, as well as the potential future domains of development. Spallation reactions modeling is a representative case of continuous studies aiming at understanding a reaction mechanism and which end up in a powerful tool.Comment: 59 pages, 54 figures, Revie

    Theoretical overview on high-energy emission in microquasars

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    Microquasar (MQ) jets are sites of particle acceleration and synchrotron emission. Such synchrotron radiation has been detected coming from jet regions of different spatial scales, which for the instruments at work nowadays appear as compact radio cores, slightly resolved radio jets, or (very) extended structures. Because of the presence of relativistic particles and dense photon, magnetic and matter fields, these outflows are also the best candidates to generate the very high-energy (VHE) gamma-rays detected coming from two of these objects, LS 5039 and LS I +61 303, and may be contributing significantly to the X-rays emitted from the MQ core. In addition, beside electromagnetic radiation, jets at different scales are producing some amount of leptonic and hadronic cosmic rays (CR), and evidences of neutrino production in these objects may be eventually found. In this work, we review on the different physical processes that may be at work in or related to MQ jets. The jet regions capable to produce significant amounts of emission at different wavelengths have been reduced to the jet base, the jet at scales of the order of the size of the system orbital semi-major axis, the jet middle scales (the resolved radio jets), and the jet termination point. The surroundings of the jet could be sites of multiwavelegnth emission as well, deserving also an insight. We focus on those scenarios, either hadronic or leptonic, in which it seems more plausible to generate both photons from radio to VHE and high-energy neutrinos. We briefly comment as well on the relevance of MQ as possible contributors to the galactic CR in the GeV-PeV range.Comment: Astrophysics & Space Science, in press (invited talk in the conference: The multimessenger approach to the high-energy gamma-ray sources", Barcelona/Catalonia, in July 4-7); 10 pages, 6 figures, 2 tables (one reference corrected
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