1,572 research outputs found

    Comercio de Marfil: el alto precio de un negocio que amenaza las especies

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    Treball presentat a l'assignatura de Deontologia i Veterinària Legal (21223

    Composição e distribuição de Darwinulidae (Crustacea, Ostracoda) no vale aluvial do alto rio Paraná, Brasil

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    The occurrence and abundance of darwinulid ostracods, as well as environmental factors influencing these patterns, were investigated in the alluvial valley of the upper Paraná River. Ostracods were sampled from several substrates, like littoral sediments and pleuston, which included several aquatic macrophytes species, from 31 localities (lentic and lotic) belonging to different riverine systems. Eight darwinulid species were found, representing all genera from this family. Alicenula serricaudata, Vestalenula pagliolii, and Penthesilenula brasiliensis were the most common species. Cluster analysis based on the composition and abundance of darwinulid communities revealed the presence of five associations. Darwinula stevensoni, Vestalenula botocuda, and Penthesilenula aotearoa were almost exclusive to lotic environments. A Mantel multiple test showed that the occurrence and distribution of darwinulid ostracods were significantly related to types of habitat and systems, but not to abiotic variables. It thus seems that the hydrodynamic fluctuations of these environments are probably more important to darwinulid distribution than the limnological characteristics.A ocorrência e abundância de ostrácodes darwinulídeos, bem como os fatores ambientais que influenciam estes padrões, foram investigadas no vale aluvial do alto rio Paraná. Os ostrácodes foram coletados em vários substratos, como sedimentos litorâneos e plêuston, o qual incluiu várias espécies de macrófitas aquáticas, de 31 ambientes (lênticos e lóticos) pertencentes a diferentes sistemas fluviais. Oito espécies de darwinulídeos foram encontradas, representando todos os gêneros desta família. Alicenula serricaudata, Vestalenula pagliolii e Penthesilenula brasiliensis foram as espécies mais comuns. A análise de agrupamento, baseada na composição e abundância das comunidades de darwinulídeos, revelou a presença de cinco associações. Darwinula stevensoni, Vestalenula botocuda e Penthesilenula aotearoa foram praticamente exclusivas de ambientes lóticos. O teste de Mantel múltiplo evidenciou que a ocorrência e distribuição de ostrácodes estiveram significantemente relacionadas aos tipos de hábitat e sistema, mas não às variáveis abióticas. Desta forma, parece que as flutuações hidrodinâmicas destes ambientes atuam mais fortemente na distribuição de darwinulídeos que as características limnológicas

    Spillover events of rabbit haemorrhagic disease virus 2 (recombinant GI.4P-GI.2) from Lagomorpha to Eurasian badger

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    Rabbit haemorrhagic disease (RHD) is a major threat to domestic and wild European rabbits. Presently, in Europe, the disease is caused mainly by Rabbit haemorrhagic disease virus 2 (RHDV2/b or Lagovirus europaeus GI.2), the origin of which is still unclear, as no RHDV2 reservoir hosts were identified. After the RHDV2 emergence in 2010, viral RNA was detected in a few rodent species. Furthermore, RHDV2 was found to cause disease in some hare species resembling the disease in rabbits, evidencing the ability of the virus to cross the species barrier. In this study, through molecular, histopathologic, antigenic and morphological evidences, we demonstrate the presence and replication of RHDV2 in Eurasian badgers (Meles meles) found dead in the district of Santarém, Portugal, between March 2017 and January 2020. In two of these seven animals, we further classify the RHDV2 as a Lagovirus europaeus recombinant GI.4P‐GI.2. Our results indicate that Meles meles is susceptible to RHDV2, developing systemic infection, and excreting the virus in the faeces. Given the high viral loads seen in several organs and matrices, we believe that transmission to the wild rabbit is likely. Furthermore, transmission electron microscopy data shows the presence of Calicivirus compatible virions in the nucleus of hepatocytes, which has not been demonstrated before and constitutes a paradigm shift for caliciviruses’s replication cycle

    Hepatic steatosis in people older and younger than fifty who are living with HIV and HIV-negative controls: A cross-sectional study nested within the POPPY cohort

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    BACKGROUND: Hepatic steatosis is a major cause of chronic liver disease associated with several negative health outcomes. We compared the prevalence of and factors associated with steatosis in people living with and without HIV. METHODS: Older (>50 years) and younger (50 years) underwent liver transient elastography examination with controlled attenuation parameter (steatosis ≥238 dB/m, moderate/severe steatosis ≥280 dB/m, liver fibrosis ≥7.1 kPa). We compared groups using logistic regression/Chi-squared/Fisher's exact/Kruskal–Wallis tests. RESULTS: In total, 317 participants (109 older people with HIV; 101 younger people with HIV; 107 HIV-negative controls) were predominantly white (86%) and male (76%), and 21% were living with obesity (body mass index ≥30 kg/m2). Most (97%) people with HIV had undetectable HIV RNA. The prevalence of fibrosis was 8.4%, 3.0%, and 6.5% in the three groups, respectively (p = 0.26). Fibrosis was predominately (>65%) mild. The prevalence of steatosis was the same in older people with HIV (66.4%) and controls (66.4%) but lower in younger people with HIV (37.4%; p < 0.001). After adjustment, younger people with HIV were less likely to have steatosis (odds ratio [OR] 0.26; 95% confidence interval [CI] 0.14–0.52) than controls, but male sex (OR 2.45; 95% CI 1.20–4.50) and high waist-to-hip ratio (OR 3.04; 95% CI 1.74–5.33) were associated with an increased odds of steatosis. We found no association between steatosis and HIV-related variables. CONCLUSIONS: The prevalence of hepatic steatosis and fibrosis was similar between older participants regardless of HIV status. Age, sex, and abdominal obesity, but not HIV-related variables, were associated with steatosis. Interventions for controlling obesity should be integrated into routine HIV care

    THE RHYTHM OF FAIRALL 9. I. OBSERVING THE SPECTRAL VARIABILITY WITH XMM-NEWTON AND NuSTAR

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    © 2016. The American Astronomical Society. All rights reserved. We present a multi-epoch X-ray spectral analysis of the Seyfert 1 galaxy Fairall 9. Our analysis shows that Fairall 9 displays unique spectral variability in that its ratio residuals to a simple absorbed power law in the 0.5-10 keV band remain constant with time in spite of large variations in flux. This behavior implies an unchanging source geometry and the same emission processes continuously at work at the timescale probed. With the constraints from NuSTAR on the broad-band spectral shape, it is clear that the soft excess in this source is a superposition of two different processes, one being blurred ionized reflection in the innermost parts of the accretion disk, and the other a continuum component such as a spatially distinct Comptonizing region. Alternatively, a more complex primary Comptonization component together with blurred ionized reflection could be responsible

    NuSTAR observations of Mrk 766: Distinguishing reflection from absorption

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    We present two new NuSTAR observations of the narrow line Seyfert 1 (NLS1) galaxy Mrk 766 and give constraints on the two scenarios previously proposed to explain its spectrum and that of other NLS1s: relativistic reflection and partial covering. The NuSTAR spectra show a strong hard (> 15 keV) X-ray excess, while simultaneous soft X-ray coverage of one of the observations provided by XMM-Newton constrains the ionised absorption in the source. The pure reflection model requires a black hole of high spin (a > 0.92) viewed at a moderate inclination (i = 46 +1 −4 ). The pure partial covering model requires extreme parameters: the cut-off of the primary continuum is very low (22 +7 −5 keV) in one observation and the intrinsic X-ray emission must provide a large fraction (75%) of the bolometric luminosity. Allowing a hybrid model with both partial covering and reflection provides more reasonable absorption parameters and relaxes the constraints on reflection parameters. The fractional variability reduces around the iron K band and at high energies including the Compton hump, suggesting that the reflected emission is less variable than the continuum

    Two chemically similar stellar overdensities on opposite sides of the plane of the Galaxy

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    Our Galaxy is thought to have undergone an active evolutionary history dominated by star formation, the accretion of cold gas, and, in particular, mergers up to 10 gigayear ago. The stellar halo reveals rich fossil evidence of these interactions in the form of stellar streams, substructures, and chemically distinct stellar components. The impact of dwarf galaxy mergers on the content and morphology of the Galactic disk is still being explored. Recent studies have identified kinematically distinct stellar substructures and moving groups, which may have extragalactic origin. However, there is mounting evidence that stellar overdensities at the outer disk/halo interface could have been caused by the interaction of a dwarf galaxy with the disk. Here we report detailed spectroscopic analysis of 14 stars drawn from two stellar overdensities, each lying about 5 kiloparsecs above and below the Galactic plane - locations suggestive of association with the stellar halo. However, we find that the chemical compositions of these stars are almost identical, both within and between these groups, and closely match the abundance patterns of the Milky Way disk stars. This study hence provides compelling evidence that these stars originate from the disk and the overdensities they are part of were created by tidal interactions of the disk with passing or merging dwarf galaxies.Comment: accepted for publication in Natur

    An iron K component to the ultrafast outflow in NGC 1313 X-1

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    We present the detection of an absorption feature at EE = 8.770.06+0.05^{+0.05}_{-0.06} keV in the combined X-ray spectrum of the ultraluminous X-ray source NGC 1313 X-1 observed with XMM-Newton\textit{XMM-Newton} and NuSTAR\textit{NuSTAR}, significant at the 3σ\sigma level. If associated with blueshifted ionized iron, the implied outflow velocity is ~0.2cc for Fe XXVI, or ~0.25cc for Fe XXV. These velocities are similar to the ultrafast outflow seen in absorption recently discovered in this source at lower energies by XMM-Newton\textit{XMM-Newton}, and we therefore conclude that this is an iron component to the same outflow. Photoionization modeling marginally prefers the Fe XXV solution, but in either case the outflow properties appear to be extreme, potentially supporting a super-Eddington hypothesis for NGC 1313 X-1.M.J.M. acknowledges support from an STFC Ernest Rutherford fellowship, C.P. and A.C.F. acknowledge support from ERC Advanced Grant 340442, and D.B. acknowledges financial support from the French Space Agency (CNES). This research has made use of data obtained with NuSTAR, a project led by Caltech, funded by NASA, and managed by NASA/JPL, and has utilized the NUSTARDAS software package, jointly developed by the ASDC (Italy) and Caltech (USA). This research has also made use of data obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States
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