116 research outputs found

    Luís António Verney: apóstolo cívico do Iluminismo em Portugal

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    Vida e obra de Luís António Verney: apóstolo cívico do Iluminismo em Portugalinfo:eu-repo/semantics/publishedVersio

    A Psicologia Positiva e as Organizações

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    Early Inflammatory Biomarkers as Predictive Factors for Freedom from Infection after Colorectal Cancer Surgery: A Prospective Cohort Study

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    Different biomarkers are useful in diagnosing infections. The aim of this work was to clarify the relation between different inflammatory biomarkers (white blood cell [WBC] count, C-reactive protein [CRP], procalcitonin [PCT], and C-reactive protein-to-albumin ratio [CAR]) and early infectious complications after colorectal surgery.info:eu-repo/semantics/publishedVersio

    Práticas artísticas no ensino básico e secundário

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    A educação pela arte faz-se através dos seus materiais, da sua operação, da transformação das matérias em ideias novas, em novas coisas. No seu sucesso está implicada uma literacia, uma capacidade interpretativa, ou crítica, sobre a semiosfera cada vez mais povoada, saturada de mensagens parasitárias. A educação implica uma leitura do mundo (Paulo Freire), que se projeta na interpretação de todas as camadas de expressão contemporânea, muitas vezes massificada, por vezes ainda identitária e significativa. Fala-se aqui de valorizar a identidade, exercer a pedagogia da diferença através de uma capacidade problematizadora. No seu contexto, podem exercer-se pedagogias que exploram a visão crítica do artista em interação com a escola, o artista em residência, no movimento A/ R/ Tography. Ou também exercer-se uma pedagogia triangular, centrando a arte, o contexto, a produção e a sua leitura como uma metodologia (Ana Mae Barbosa). O contexto contemporâneo é pós digital, os conteúdos não pesam nos suportes, e transmitem-se por “dentes azuis” ou redes com muitos Gs (G de Geração sem peso que sucede ao peso da aceleração gravítica). Neste campo pode delinear-se uma metodologia que alicerça o projeto ancorado nos estudos críticos sobre Cultura Visual (Fernando Hernández). Digamos que as práticas pedagógicas se cruzam em diversas direções, tacteando eficácias, expressões, capacidades, inovação. O contexto é cada vez mais voraz: a pele da cultura gosta de massagens (Kerkhove; McLuhan). A Matéria-Prima de que se fala nesta revista é aquela que devolve ao seu lugar um ponto crítico da pós modernidade: o do significante. Os sintagmas são sempre processos, e neles se formam as subjectividades, ou seja, as identidades: no desenrolar do ser, onde se produz verdadeiramente o sentido, bem junto do aqui-e-agora onde está a Matéria-Prima (Foucault).info:eu-repo/semantics/publishedVersio

    Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory

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    In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (Xmax) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with Xmax distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energy-dependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations of the proton-proton cross-sections from low-energy accelerator data

    Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory

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    The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gamma rays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle

    Combined fit to the spectrum and composition data measured by the Pierre Auger Observatory including magnetic horizon effects

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    The measurements by the Pierre Auger Observatory of the energy spectrum and mass composition of cosmic rays can be interpreted assuming the presence of two extragalactic source populations, one dominating the flux at energies above a few EeV and the other below. To fit the data ignoring magnetic field effects, the high-energy population needs to accelerate a mixture of nuclei with very hard spectra, at odds with the approximate E2^{-2} shape expected from diffusive shock acceleration. The presence of turbulent extragalactic magnetic fields in the region between the closest sources and the Earth can significantly modify the observed CR spectrum with respect to that emitted by the sources, reducing the flux of low-rigidity particles that reach the Earth. We here take into account this magnetic horizon effect in the combined fit of the spectrum and shower depth distributions, exploring the possibility that a spectrum for the high-energy population sources with a shape closer to E2^{-2} be able to explain the observations

    Measuring the muon content of inclined air showers using AERA and the water-Cherenkov detector array of the Pierre Auger Observatory

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    Investigating multiple elves and halos above strong lightning with the fluorescence detectors of the Pierre Auger Observatory

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    ELVES are being studied since 2013 with the twenty-four FD Telescopes of the Pierre Auger Observatory, in the province of Mendoza (Argentina), the world’s largest facility for the study of ultra-high energy cosmic rays. This study exploits a dedicated trigger and extended readout. Since December 2020, this trigger has been extended to the three High levation Auger Telescopes (HEAT), which observe the night sky at elevation angles between 30 and 60 degrees, allowing a study of ELVES from closer lightning. The high time resolution of the Auger telescopes allows us to upgrade reconstruction algorithms and to do detailed studies on multiple ELVES. The origin of multiple elves can be studied by analyzing the time difference and the amplitude ratio between flashes and comparing them with the properties of radio signals detected by the ENTLN lightning network since 2018. A fraction of multi-ELVES can also be interpreted as halos following ELVES. Halos are disc-shaped light transients emitted at 70-80 km altitudes, appearing at the center of the ELVES rings, due to the rearrangement of electric charges at the base of the ionosphere after a strong lightning event
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