20,835 research outputs found

    GeMs/GSAOI observations of La Serena 94: an old and far open cluster inside the solar circle

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    Physical properties were derived for the candidate open cluster La Serena 94, recently unveiled by the VVV collaboration. Thanks to the exquisite angular resolution provided by GeMS/GSAOI, we could characterize this system in detail, for the first time, with deep photometry in JHKs_{s} - bands. Decontaminated JHKs_{s} diagrams reach about 5 mag below the cluster turnoff in H. The locus of red clump giants in the colour - colour diagram, together with an extinction law, was used to obtain an average extinction of AV=14.18±0.71A_V =14.18 \pm 0.71. The same stars were considered as standard - candles to derive the cluster distance, 8.5±1.08.5 \pm 1.0 kpc. Isochrones were matched to the cluster colour - magnitude diagrams to determine its age, logt(yr)=9.12±0.06\log{t(yr)}=9.12\pm 0.06, and metallicity, Z=0.02±0.01Z=0.02\pm0.01. A core radius of rc=0.51±0.04r_{c}=0.51\pm 0.04 pc was found by fitting King models to the radial density profile. By adding up the visible stellar mass to an extrapolated mass function, the cluster mass was estimated as M=(2.65±0.57)×103M=(2.65\pm0.57) \times 10^3 M_{\odot}, consistent with an integrated magnitude of MK=5.82±0.16M_{K}=-5.82\pm0.16 and a tidal radius of rt=17.2±2.1r_{t}=17.2\pm2.1 pc. The overall characteristics of La Serena 94 confirm that it is an old open cluster located in the Crux spiral arm towards the fourth Galactic quadrant and distant 7.30±0.497.30\pm 0.49 kpc from the Galactic centre. The cluster distorted structure, mass segregation and age indicate that it is a dynamically evolved stellar system.Comment: 16 pages, 24 figures, 2 Tables, accepted by MNRAS; corrected typo

    Um grande surto de Legionella ausente do debate público

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    The Legionnaires’ disease outbreak that hit Portugal in November 2014 was the third largest worldwide and was declared a “great public health emergency”. Nonetheless, the Portuguese outbreak, despite killing 12 people and infecting 375 others did not promote extensive media coverage, nor did it make it into the political debate. We conducted a quantitative analysis of 83 news pieces on Legionella published in four national newspapers, and interviewed the journalists who covered this outbreak. The communication process was controlled by a small group of official sources and the outbreak was pushed away from news lineups due to two political scandals. The production of another news wave made the outbreak’s news wave to break prematurely.O surto de Legionella que atingiu Portugal em novembro de 2014 foi o terceiro maior em nível mundial, constituindo “uma grande emergência de saúde pública”. Ainda assim, o surto português não promoveu uma longa cobertura mediática, apesar das 12 mortes e 375 pessoas infetadas. Nem entrou no debate político. Fizemos uma análise quantitativa das 83 notícias sobre Legionella publicadas em quatro jornais nacionais, e conduzimos entrevistas com os jornalistas que cobriram este surto. O processo comunicativo foi controlado por um pequeno grupo de fontes oficiais, e o surto foi rapidamente afastado dos alinhamentos noticiosos, sendo substituído por dois escândalos políticos. A produção de outra onda noticiosa fez com que a onda noticiosa do surto de Legionella se quebrasse prematuramente.(undefined)info:eu-repo/semantics/publishedVersio

    Instanton Corrected Non-Supersymmetric Attractors

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    We discuss non-supersymmetric attractors with an instanton correction in Type IIA string theory compactified on a Calabi-Yau three-fold at large volume. For a stable non-supersymmetric black hole, the attractor point must minimize the effective black hole potential. We study the supersymmetric as well as non-supersymmetric attractors for the D0-D4 system with instanton corrections. We show that in simple models, like the STU model, the flat directions of the mass matrix can be lifted by a suitable choice of the instanton parameters.Comment: Minor modifications, Corrected typos, 38 pages, 1 figur

    Genomic wide-selection for tick resistance in Hereford and Braford cattle via reaction norm model.

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    The objective of this study was to compare a conventional genomic model (GBLUP) and its extension to a linear reaction norm model (GLRNM) specifying genotype by environment interaction (G*E) for tick resistance in Brazilian cattle. Tick counts (TC) from 4,363 Hereford and Braford cattle from 146 contemporary groups (CG) were available of which 3,591 animals had BovineSNP50 Illumina v2 BeadChip genotypes. The reaction norm covariate was based on CG estimates of TC from a first-step model. Analysis was conducted based on adapting the single step GBLUP/REML procedure. Fivefold cross validation based on K-means and random partitioning was used to compare the fit of the two models. Cross validation correlations were strong and not significantly different between models for either partitioning strategy. Nevertheless, it seems apparent that G*E for tick infestation exists and can captured by GLRNM models

    Genotype by environment interaction for tick resistance of Hereford and Braford beef cattle using reaction norm model.

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    The cattle tick is a parasite that adversely affects livestock performance in tropical areas. Although countries such as Australia and Brazil have developed genetic evaluations for tick resistance, these evaluations have not considered genotype by environment (G*E) interactions. Genetic gains could be adversely affected, since breed-stock comparisons are environmentally dependent on the presence of G*E interactions, particularly if residual vari-ability is also heterogeneous across environments. The objective of this study was to infer upon the existence of G*E interactions for tick resistance of cattle based on various models with different assumptions of genetic and residual variability.Article 3
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