520 research outputs found

    High arrhythmic risk in antero-septal acute myocardial ischemia is explained by increased transmural reentry occurrence

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    Acute myocardial ischemia is a precursor of sudden arrhythmic death. Variability in its manifestation hampers understanding of arrhythmia mechanisms and challenges risk stratification. Our aim is to unravel the mechanisms underlying how size, transmural extent and location of ischemia determine arrhythmia vulnerability and ecG alterations. High performance computing simulations using a human torso/biventricular biophysically-detailed model were conducted to quantify the impact of varying ischemic region properties, including location (LAD/LcX occlusion), transmural/subendocardial ischemia, size, and normal/slow myocardial propagation. ecG biomarkers and vulnerability window for reentry were computed in over 400 simulations for 18 cases evaluated. Two distinct mechanisms explained larger vulnerability to reentry in transmural versus subendocardial ischemia. Macro-reentry around the ischemic region was the primary mechanism increasing arrhythmic risk in transmural versus subendocardial ischemia, for both LAD and LcX occlusion. transmural micro-reentry at the ischemic border zone explained arrhythmic vulnerability in subendocardial ischemia, especially in LAD occlusion, as reentries were favoured by the ischemic region intersecting the septo-apical region. St elevation reflected ischemic extent in transmural ischemia for LCX and LAD occlusion but not in subendocardial ischemia (associated with mild St depression). the technology and results presented can inform safety and efficacy evaluation of anti-arrhythmic therapy in acute myocardial ischemia

    LEMUR: Large European Module for Solar Ultraviolet Research

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    The solar outer atmosphere is an extremely dynamic environment characterized by the continuous interplay between the plasma and the magnetic field that generates and permeates it. Such interactions play a fundamental role in hugely diverse astrophysical systems, but occur at scales that cannot be studied outside the solar system. Understanding this complex system requires concerted, simultaneous solar observations from the visible to the vacuum ultraviolet (VUV) and soft X-rays, at high spatial resolution (between 0.1 and 0.3), at high temporal resolution (on the order of 10 s, i.e., the time scale of chromospheric dynamics), with a wide temperature coverage (0.01 MK to 20 MK, from the chromosphere to the flaring corona), and the capability of measuring magnetic fields through spectropolarimetry at visible and near-infrared wavelengths. Simultaneous spectroscopic measurements sampling the entire temperature range are particularly important. These requirements are fulfilled by the Japanese Solar-C mission (Plan B), composed of a spacecraft in a geosynchronous orbit with a payload providing a significant improvement of imaging and spectropolarimetric capabilities in the UV, visible, and near-infrared with respect to what is available today and foreseen in the near future. The Large European Module for solar Ultraviolet Research (LEMUR), described in this paper, is a large VUV telescope feeding a scientific payload of high-resolution imaging spectrographs and cameras. LEMUR consists of two major components: a VUV solar telescope with a 30 cm diameter mirror and a focal length of 3.6 m, and a focal-plane package composed of VUV spectrometers covering six carefully chosen wavelength ranges between 170 Angstrom and 1270 Angstrom. The LEMUR slit covers 280 on the Sun with 0.14 per pixel sampling. In addition, LEMUR is capable of measuring mass flows velocities (line shifts) down to 2 km s 1 or better. LEMUR has been proposed to ESA as the European contribution to the Solar C mission

    Ciencias de la BiologĂ­a y AgronomĂ­a

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    Este volumen I contiene 17 capĂ­tulos arbitrados que se ocupan de estos asuntos en TĂłpicos Selectos de Ciencias de la BiologĂ­a y AgronomĂ­a, elegidos de entre las contribuciones, reunimos algunos investigadores y estudiantes. Se presenta un Estudio Comparativo de los Recursos HidrolĂłgico-Forestales de la Microcuenca de la Laguna de Epatlan, Pue. (1993 a 2014); la SituaciĂłn Actual de la Mancha de Asfalto en MaĂ­z (Zea mays L.) en los Municipios de Jiquipilas y Ocozocoautla, Chiapas, MĂ©xico; las poblaciones sobresalientes de maĂ­z de la raza Zapalote Chico, en la RegiĂłn Istmeña de Oaxaca; Se indica el Ă­ndice de ĂĄrea foliar de cultivo de Chile Poblano mediante dos mĂ©todos en condiciones protegidas; Esquivel, UrzĂșa y RamĂ­rez exploran el efecto de la biofertilizaciĂłn con Azospirillum en el crecimiento y producciĂłn de Jitomate; esbozan su artĂ­culo sobre la determinaciĂłn del nivel de Heterosis en hĂ­bridos de MaĂ­z para la Comarca Lagunera; una investigaciĂłn sobre la estabilizaciĂłn de semilla de Solanum lycopersicum durante el almacenamiento y estimulaciĂłn de la germinaciĂłn; acotan sobre el CTAB como una nueva opciĂłn para la detecciĂłn de Huanglongbing en cĂ­tricos, plantean su evaluaciĂłn sobre el aluminio y cĂłmo afecta la vida de florero de Heliconia psittacorum; indican sobre el impacto del H-564C, como un hĂ­brido de maĂ­z con alta calidad de proteina para el trĂłpico hĂșmedo de MĂ©xico; presetan su investigaciĂłn sobre la producciĂłn de Piña Cayena Lisa y MD2 (Ananas comosus L.) en condiciones de Loma Bonita, en Oaxaca; acotan sobre el efecto de coberteras como control biolĂłgico por conservaciĂłn contra ĂĄfidos en Nogal Pecanero; esbozan sobre la caracterizaciĂłn de cuatro genotipos de Frijol Negro en MartĂ­nez de la Torre, Veracruz, MĂ©xico; presentan una caracterizaciĂłn hidroecolĂłgica de la microcuenca de Arroyo Prieto, YurirĂ­a, Gto., y alternativas para su restauraciĂłn ambiental; presentan su investigaciĂłn sobre el efecto del hongo Beauveria bassiana sobre solubilizaciĂłn de fosfatos y la disponibilidad de fĂłsforo en el suelo; plantean su investigaciĂłn sobre la GerminaciĂłn y regeneraciĂłn in vitro de Epidendrum falcatum LINDL; esbozan su artĂ­culo sobre genotipos de frijol negro y su tolerancia a sequĂ­a terminal en Veracruz, MĂ©xico

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

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    Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

    Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

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    Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio
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