185 research outputs found

    [14] Una aportación para las “escuelas sostenibles” en la década de la educación para el desarrollo sostenible

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    En el contexto de la Década de la Educación para el Desarrollo sostenible presentamos nuestra aportación a las “Escuelas Sostenibles”. Ésta surge como fruto de la reflexión después de una investigación realizada en torno a una experiencia concreta: “Ecocentros de Extremadura”, con el fin de contribuir al necesario proceso madurativo de las mismas. Con ello estaremos más cerca de lograr hacer una escuela coherente con los retos de la educación ambiental para el siglo XXI.Palabras clave: Escuelas sostenibles; ecoauditorías escolares; investigación en educación ambiental; práctica educativa en la escuela.A contribution to "sustainable schools" in the decade of education for sustainable developmentAs part of the context of the Decade of Education for Sustainable Development, we present our contribution to "Sustainable Schools". It arose as a result of reflection following as study conducted on a specific experience, "The 'Ecocentros' of Extremadura", with the aim of furthering the necessary maturation process of sustainable schools, and bringing us closer to achieving a school that is coherent with the challenges of environmental education for the XXI century.Keywords: Sustainable schools; school environmental audits, environmental education research; educational practice in the school

    Microstructure, texture and tensile properties of ultrafine/nano grained magnesium alloy processed by accumulative back extrusion

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    An AZ31 wrought magnesium alloy was processed by employing multipass accumulative back extrusion process. The obtained microstructure, texture and room temperature tensile properties were characterized and discussed. Ultrafine grained microstructure including nano grains were developed, where the obtained mean grain size was decreased from 8 to 0.5 µm by applying consecutive passes. The frequency of both low angle and high angle boundaries increased after processing. Strength of the experimental alloy was decreased after processing, which was attributed to the obtained texture involving the major component lying inclined to the deformation axis. Both the uniform and post uniform elongations of the processed materials were increased after processing, where a total elongation of 68 pct was obtained after six-pass deformation. The contribution of different twinning and slip mechanism was described by calculating corresponding Schmid factors. The operation of prismatic slip was considered as the major deformation contributor. The significant increase in post uniform deformation of the processed material was discussed relying on the occurrence of grain boundary sliding associated with the operation of prismatic slip.Postprint (author's final draft

    A phase I randomized therapeutic MVA-B vaccination improves the magnitude and quality of the T cell immune responses in HIV-1-infected subjects on HAART

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    Trial Design Previous studies suggested that poxvirus-based vaccines might be instrumental in the therapeutic HIV field. A phase I clinical trial was conducted in HIV-1-infected patients on highly active antiretroviral therapy (HAART), with CD4 T cell counts above 450 cells/mm3 and undetectable viremia. Thirty participants were randomized (2:1) to receive either 3 intramuscular injections of MVA-B vaccine (coding for clade B HIV-1 Env, Gag, Pol and Nef antigens) or placebo, followed by interruption of HAART. Methods The magnitude, breadth, quality and phenotype of the HIV-1-specific T cell response were assayed by intracellular cytokine staining (ICS) in 22 volunteers pre- and post-vaccination. Results MVA-B vaccine induced newly detected HIV-1-specific CD4 T cell responses and expanded pre-existing responses (mostly against Gag, Pol and Nef antigens) that were high in magnitude, broadly directed and showed an enhanced polyfunctionality with a T effector memory (TEM) phenotype, while maintaining the magnitude and quality of the pre-existing HIV-1- specific CD8 T cell responses. In addition, vaccination also triggered preferential CD8+ T cell polyfunctional responses to the MVA vector antigens that increase in magnitude after two and three booster doses

    Effects of Data Quality Vetoes on a Search for Compact Binary Coalescences in Advanced LIGO's First Observing Run

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    The first observing run of Advanced LIGO spanned 4 months, from September 12, 2015 to January 19, 2016, during which gravitational waves were directly detected from two binary black hole systems, namely GW150914 and GW151226. Confident detection of gravitational waves requires an understanding of instrumental transients and artifacts that can reduce the sensitivity of a search. Studies of the quality of the detector data yield insights into the cause of instrumental artifacts and data quality vetoes specific to a search are produced to mitigate the effects of problematic data. In this paper, the systematic removal of noisy data from analysis time is shown to improve the sensitivity of searches for compact binary coalescences. The output of the PyCBC pipeline, which is a python-based code package used to search for gravitational wave signals from compact binary coalescences, is used as a metric for improvement. GW150914 was a loud enough signal that removing noisy data did not improve its significance. However, the removal of data with excess noise decreased the false alarm rate of GW151226 by more than two orders of magnitude, from 1 in 770 years to less than 1 in 186000 years.Comment: 27 pages, 13 figures, published versio

    A search of the Orion spur for continuous gravitational waves using a "loosely coherent" algorithm on data from LIGO interferometers

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    We report results of a wideband search for periodic gravitational waves from isolated neutron stars within the Orion spur towards both the inner and outer regions of our Galaxy. As gravitational waves interact very weakly with matter, the search is unimpeded by dust and concentrations of stars. One search disk (A) is 6.876.87^\circ in diameter and centered on 20h10m54.71s+333325.29"20^\textrm{h}10^\textrm{m}54.71^\textrm{s}+33^\circ33'25.29", and the other (B) is 7.457.45^\circ in diameter and centered on 8h35m20.61s464925.151"8^\textrm{h}35^\textrm{m}20.61^\textrm{s}-46^\circ49'25.151". We explored the frequency range of 50-1500 Hz and frequency derivative from 00 to 5×109-5\times 10^{-9} Hz/s. A multi-stage, loosely coherent search program allowed probing more deeply than before in these two regions, while increasing coherence length with every stage. Rigorous followup parameters have winnowed initial coincidence set to only 70 candidates, to be examined manually. None of those 70 candidates proved to be consistent with an isolated gravitational wave emitter, and 95% confidence level upper limits were placed on continuous-wave strain amplitudes. Near 169169 Hz we achieve our lowest 95% CL upper limit on worst-case linearly polarized strain amplitude h0h_0 of 6.3×10256.3\times 10^{-25}, while at the high end of our frequency range we achieve a worst-case upper limit of 3.4×10243.4\times 10^{-24} for all polarizations and sky locations.Comment: Fixed minor typo - duplicate name in the author lis

    Search of the Orion spur for continuous gravitational waves using a loosely coherent algorithm on data from LIGO interferometers

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    We report results of a wideband search for periodic gravitational waves from isolated neutron stars within the Orion spur towards both the inner and outer regions of our Galaxy. As gravitational waves interact very weakly with matter, the search is unimpeded by dust and concentrations of stars. One search disk (A) is 6.87° in diameter and centered on 20h10m54.71s+33°33′25.29′′, and the other (B) is 7.45° in diameter and centered on 8h35m20.61s-46°49′25.151′′. We explored the frequency range of 50-1500 Hz and frequency derivative from 0 to -5×10-9 Hz/s. A multistage, loosely coherent search program allowed probing more deeply than before in these two regions, while increasing coherence length with every stage. Rigorous follow-up parameters have winnowed the initial coincidence set to only 70 candidates, to be examined manually. None of those 70 candidates proved to be consistent with an isolated gravitational-wave emitter, and 95% confidence level upper limits were placed on continuous-wave strain amplitudes. Near 169 Hz we achieve our lowest 95% C.L. upper limit on the worst-case linearly polarized strain amplitude h0 of 6.3×10-25, while at the high end of our frequency range we achieve a worst-case upper limit of 3.4×10-24 for all polarizations and sky locations. © 2016 American Physical Society

    Supplement: "Localization and broadband follow-up of the gravitational-wave transient GW150914" (2016, ApJL, 826, L13)

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    This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands

    Searches for continuous gravitational waves from nine young supernova remnants

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    We describe directed searches for continuous gravitational waves in data from the sixth LIGO science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of ten. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering F-statistic. We found no credible gravitational-wave signals. We set 95% confidence upper limits as strong (low) as 4×10254\times10^{-25} on intrinsic strain, 2×1072\times10^{-7} on fiducial ellipticity, and 4×1054\times10^{-5} on r-mode amplitude. These beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star ellipticities and r-mode amplitudes.Comment: Science summary available at http://www.ligo.org/science/Publication-S6DirectedSNR/index.ph

    Multimessenger Search for Sources of Gravitational Waves and High-Energy Neutrinos: Results for Initial LIGO-Virgo and IceCube

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    We report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of gravitational-wave emission energy of 10210^{-2}\,M_\odotc2^2 at 150\sim 150\,Hz with 60\sim 60\,ms duration, and high-energy neutrino emission of 105110^{51}\,erg comparable to the isotropic gamma-ray energy of gamma-ray bursts, we limit the source rate below 1.6×1021.6 \times 10^{-2}\,Mpc3^{-3}yr1^{-1}. We also examine how combining information from gravitational waves and neutrinos will aid discovery in the advanced gravitational-wave detector era
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