750 research outputs found

    Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

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    Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{6×10196\times 10^{19}eV}. The anisotropy was measured by the fraction of arrival directions that are less than 3.13.1^\circ from the position of an active galactic nucleus within 75 Mpc (using the V\'eron-Cetty and V\'eron 12th12^{\rm th} catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (386+7)(38^{+7}_{-6})%, compared with 2121% expected for isotropic cosmic rays. This is down from the early estimate of (6913+11)(69^{+11}_{-13})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201

    Ischemic postconditioning reduces reperfusion arrhythmias by adenosine receptors and protein kinase C activation but is independent of KATP channels or connexin 43

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    Funding: This study was supported by Secretaría de Investigación, Internacionales y Posgrado, Universidad Nacional de Cuyo (06/J505) and by the Spanish, Ministerio de Ciencia, Innovación y Universidades, Instituto de Salud Carlos III (CIBERCV), cofinanced by the European Regional Development Fund (ERDF-FEDER, a way to build Europe), and by Fundació La Marató de TV3 (n◦. 201536-10). Antonio Rodríguez-Sinovas has a consolidated Miguel Servet contract. Jose A. Sánchez was supported by the International Research Training Group 1566 on Protecting the Heart from Ischemia (PROMISE).Ischemic postconditioning (IPoC) reduces reperfusion arrhythmias but the antiarrhythmic mechanisms remain unknown. The aim of this study was to analyze IPoC electrophysiological effects and the role played by adenosine A, A and A receptors, protein kinase C, ATP-dependent potassium (K) channels, and connexin 43. IPoC reduced reperfusion arrhythmias (mainly sustained ventricular fibrillation) in isolated rat hearts, an effect associated with a transient delay in epicardial electrical activation, and with action potential shortening. Electrical impedance measurements and Lucifer-Yellow diffusion assays agreed with such activation delay. However, this delay persisted during IPoC in isolated mouse hearts in which connexin 43 was replaced by connexin 32 and in mice with conditional deletion of connexin 43. Adenosine A, A and A receptor blockade antagonized the antiarrhythmic effect of IPoC and the associated action potential shortening, whereas exogenous adenosine reduced reperfusion arrhythmias and shortened action potential duration. Protein kinase C inhibition by chelerythrine abolished the protective effect of IPoC but did not modify the effects on action potential duration. On the other hand, glibenclamide, a K inhibitor, antagonized the action potential shortening but did not interfere with the antiarrhythmic effect. The antiarrhythmic mechanisms of IPoC involve adenosine receptor activation and are associated with action potential shortening. However, this action potential shortening is not essential for protection, as it persisted during protein kinase C inhibition, a maneuver that abolished IPoC protection. Furthermore, glibenclamide induced the opposite effects. In addition, IPoC delays electrical activation and electrical impedance recovery during reperfusion, but these effects are independent of connexin 43

    The Fluorescence Detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics Research Section

    Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory

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    We present the results of searches for dipolar-type anisotropies in different energy ranges above 2.5×10172.5\times 10^{17} eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% C.L.C.L. for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations.Comment: 28 pages, 11 figure

    Uso De Filtros De Carvão Ativado Granular Associado A Microrganismos Para Remoção De Fármacos No Tratamento De água De Abastecimento

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    The way of life of modern societies has originated the daily intake of pharmaceuticals and numerous other molecules of continuous use in aquatic environments, emerging compounds that brings potential risk for human health mainly due to exposure resulted from the inevitable contamination of sources of drinking water supply and its transference to the water treatment plants (WTP) where they are not removed. The use of granular activated carbon in filters proves to be a viable option for WTP, but satisfactory efficiency requires periodic regeneration of the material, burdening the treatment costs. However, it is noted that under low filtration rates, the natural colonization of filters by microorganisms — biofilm formation — may be an alternative for increasing the lifetime of carbon, as well as to decompose these complex molecules into assimilable mineral elements, thereby reintroducing them to the natural biogeochemical cycles. This study evaluated the activated carbon with biofilm as the filter media, during 24 weeks, under laboratory conditions, considering the removal of the pharmaceuticals diclofenac sodium, ibuprofen, naproxen and amoxicillin; experienced under batch system the potential of the microorganisms adhering to the filters in degrade the tested drugs, as well as phylogenetically identified the predominant microorganisms in biodegradation. The results show drug removal over 80%. It was observed the presence of the bacteria genus Bacillus, Burkholderia, Cupriavidus, Pseudomonas, Shinella and Sphingomonas. This study allows us to infer the capacity to remove pharmaceuticals by the bacteria present in the activated carbon filters, and the possible use of this technology as an alternative for control and removal of these substances in drinking water treatment. © 2016, ABES - Associacao Brasileira de Engenharia Sanitaria e Ambiental. All rights reserved.21470972

    Search for black holes and other new phenomena in high-multiplicity final states in proton-proton collisions at root s=13 TeV

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    Search for high-mass diphoton resonances in proton-proton collisions at 13 TeV and combination with 8 TeV search

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