581 research outputs found

    Biofuel Mandating and the Green Paradox

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    Current and Future constraints on Very-Light Axion-Like Particles from X-ray observations of cluster-hosted Active Galaxies

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    We discuss our recent constraints on the coupling of Very-Light Axion-Like Particles (of masses <<1012 eV 10^{-12} \ \mathrm{eV}) to electromagnetism from ChandraChandra observations of the cluster-hosted Active Galactic Nuclei (AGN) H1821+643 and NGC1275. In both cases, the inferred high-quality AGN spectra excluded all photon-ALP couplings gaγ>(6.38.0)×1013 GeV1g_\mathrm{a\gamma} > (6.3 - 8.0) \times 10^{-13} \ {\mathrm{GeV}}^{-1} at the 99.7%99.7\% level, respectively, based on the non-detection of spectral distortions attributed to photon-ALP inter-conversion along the cluster line-of-sight. Finally, we present the prospects of tightening current bounds on such ALPs by up to a factor of 10 with next-generation X-ray observatories such as AthenaAthena, AXISAXIS and LEMLEM given their improved spectral and spatial resolution and collecting area compared to current missions.Comment: 4 pages, 1 figure. Accepted for publication to Memorie della SAIt for the Proceedings of the European Astronomical Society 2022 (EAS 2022) Annual Meeting Symposium S3 "The Dark matter multi-messenger challenge

    Identifying eroded Messinian deposits on the Maltese Islands by gypsum Sr isotopes

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    International audienceEvaporite sediments are known to have formed during the Messinian high salinity crisis that has been recognized in many Mediterranean areas. This event was however never identified on the Maltese Islands. In this study, a Sr isotopic characterization of gypsum, found as secondary minerals in the Oligocene-Miocene formations of Malta and Gozo is performed. The 87Sr/86Sr values are discussed on the basis of comparison with the surrounding rock Sr isotopic signature. The data outline two distinguishable 87Sr/86Sr ratios for gypsum according to their facies. Most of crack-infilling mineral data suggest a downward fluid circulation in the Miocene sediment associated with interaction in the currently outcropping limestones. Some gypsum crystals found as crystallized spherules show significantly lower 87Sr/86Sr ratios, close to those defined in the literature for Messinian evaporate sediments. Taken together, this may suggest that an evaporate formation of Messinian age had in the past covered the present-day sedimentary sequence in Malta and Gozo

    Henipavirus and Tioman Virus Antibodies in Pteropodid Bats, Madagascar

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    Specimens were obtained from the 3 Malagasy fruit bats, Pteropus rufus, Eidolon dupreanum, and Rousettus madagascariensis. Antibodies against Nipah, Hendra, and Tioman viruses were detected by immunoassay in 23 and by serum neutralization tests in 3 of 427 serum samples, which suggests that related viruses have circulated in Madagascar

    The yeast Candida albicans has a clonal mode of reproduction in a population of infected human immunodeficiency virus-positive patients

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    To ascertain the population structure of Candida albicans, we have carried out a multilocus enzyme electrophoresis study based on the analysis of 21 gene loci. We have thus characterized 55 strains isolated one each from 55 human immunodeficiency virus-positive patients. There is considerable polymorphism among the strains. A population-genetic analysis indicates that the two fundamental consequences of sexual reproduction (i.e., segregation and recombination) are apparently absent in this population of C. albicans. The population structure of C. albicans appears to be clonal, a state of affairs that has important medical and biological consequences

    Design and optimization of electrochemical microreactors for continuous electrosynthesis

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    The study focuses on the design and construction, as well as the theoretical and experimental optimization of electrochemical filter press microreactors for the electrosynthesis of molecules with a high added value. The main characteristics of these devices are firstly a high-specific electrochemical area to increase conversion and selectivity, and secondly the shape and size of themicrochannels designed for a uniform residence time distribution of the fluid. A heat exchanger is integrated into the microstructured electrode to rapidly remove (or supply) the heat required in exo- or endothermic reactions. The microreactors designed are used to perform-specific electrosynthesis reactions such as thermodynamically unfavorable reactions (continuous NADH regeneration), or reactions with high enthalpy changes

    Pseudomicetoma felino causado por Microsporum canis: descripción de un caso clínico y su tratamiento

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    En la presente comunicación se describe un caso clínico de dermatofitosis en un gato persa, producida por Microsporum canis, con manifestaciones cutáneas de pseudomicetoma (granuloma de Majocchi). Se detallan los diagnósticos clínico e histopatológico, así como el tratamiento instaurado
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