970 resultados para Étoiles : Wolf-Rayet


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Arbacia lixula and Paracentrotus lividus are the dominant sea urchins in the Mediterranean sublittoral, where they are key structuring species due to their grazing activity. It has been commonly accepted that competition between both species is minimized by specializing in different algal foods. A. lixula is considered to feed mainly on encrusting coralline algae, while P. lividus prefers fleshy macroalgae. We used stable isotope analysis to test if these species occupy different trophic positions at 3 locations in the western Mediterranean and one in Macaronesia. Our results show unambiguously that A. lixula always occupies a higher trophic level than P. lividus, with a δ15N comparable in some locations to strict carnivores such as Actinia schmidti or Marthasterias glacialis. A temporal monitoring at one locality showed that this signature of a higher trophic level is consistent throughout the year. These results are incompatible with the current belief of an herbivorous diet for A. lixula and suggest that it must be considered an omnivore tending to carnivory in Mediterranean ecosystems, feeding at least partially on sessile animals such as Cirripedia, Hydrozoa or Bryozoa. A parallel analysis of gut contents showed a predominance of vegetal items in both species, although A. lixula consistently had a higher abundance of animal components than P. lividus. Our results challenge the validity of using gut content observations alone for characterizing the trophic behaviour of omnivorous marine invertebrates that feed on a variety of food sources with different digestibility.

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Following protection measures implemented since the 1970s, large carnivores are currently increasing in number and returning to areas from which they were absent for decades or even centuries. Monitoring programmes for these species rely extensively on non-invasive sampling and genotyping. However, attempts to connect results of such studies at larger spatial or temporal scales often suffer from the incompatibility of genetic markers implemented by researchers in different laboratories. This is particularly critical for long-distance dispersers, revealing the need for harmonized monitoring schemes that would enable the understanding of gene flow and dispersal dynamics. Based on a review of genetic studies on grey wolves Canis lupus from Europe, we provide an overview of the genetic markers currently in use, and identify opportunities and hurdles for studies based on continent-scale datasets. Our results highlight an urgent need for harmonization of methods to enable transnational research based on data that have already been collected, and to allow these data to be linked to material collected in the future. We suggest timely standardization of newly developed genotyping approaches, and propose that action is directed towards the establishment of shared single nucleotide polymorphism panels, next-generation sequencing of microsatellites, a common reference sample collection and an online database for data exchange. Enhanced cooperation among genetic researchers dealing with large carnivores in consortia would facilitate streamlining of methods, their faster and wider adoption, and production of results at the large spatial scales that ultimately matter for the conservation of these charismatic species.

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The measurement of cardiovascular features of wild animals is important, as is the measurement in pets, for the assessment of myocardial function and the early detection of cardiac abnormalities, which could progress to heart failure. Speckle tracking echocardiography (2D STE) is a new tool that has been used in veterinary medicine, which demonstrates several advantages, such as angle independence and the possibility to provide the early diagnosis of myocardial alterations. The aim of this study was to evaluate the left myocardial function in a maned wolf by 2D STE. Thus, the longitudinal, circumferential and radial strain and strain rate were obtained, as well as, the radial and longitudinal velocity and displacement values, from the right parasternal long axis four-chamber view, the left parasternal apical four chamber view and the parasternal short axis at the level of the papillary muscles. The results of the longitudinal variables were -13.52±7.88, -1.60±1.05, 4.34±2.52 and 3.86±3.04 for strain (%), strain rate (1/s), displacement (mm) and velocity (cm/s), respectively. In addition, the radial and circumferential Strain and Strain rate were 24.39±14.23, 1.86±0.95 and -13.69±6.53, -1.01±0.48, respectively. Thus, the present study provides the first data regarding the use of this tool in maned wolves, allowing a more complete quantification of myocardial function in this species.

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The aim of the present study was the ultrasound characterization of the abdominal and pelvic regions of five maned wolves kept in captivity at the Triage Center of Wild Animals of the Federal University of Viçosa (Centro de Triagem de Animais Silvestres, Universidade Federal de Viçosa). This characterization included descriptions of ultrasonographic aspects and measurements of various structures using B-mode ultrasound. Biometric data were collected to assess the existence of significant linear correlations between these measurements and the measurements obtained by ultrasound. Additionally, hematological and serum biochemistry evaluations of the animals were performed. The ultrasound findings were similar to those available in the literature on domestic dogs, which were used for comparison as a result of the lack of published data regarding maned wolves. The latter species showed characteristics closely resembling those of the former, differing in the spleen and left renal cortex echogenicities, in the appearance of the prostatic and testicular regions and in the hepatic portal vein morphology. In the current study, the biometric values were similar to those previously published; however, no data regarding thoracic perimeter, modified crown-rump length or thoracic depth were found in the literature for this Canidae species. Statistical analysis showed the existence of a strong negative correlation between the modified crown-rump length and left renal length, between the modified crown-rump length and the right renal volume, between the thoracic perimeter and the height at the cranial pole of the left adrenal gland and between the thoracic perimeter and the height at the caudal pole of the left adrenal gland. Laboratory findings, including segmented neutrophil, eosinophil, monocyte and lymphocyte counts and the serum levels of glucose, ALT, alkaline phosphatase, urea, total protein, globulin, creatine phosphokinase, triglyceride, sodium, phosphate, potassium and chloride, were inconsistent with values found by other authors. The ultrasound is a diagnostic imaging method that must be further explored in the medicine of wild animals; therefore, additional research in this area is required.

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Poucos autores modernos deram tanta força de expressão à "afinidade eletiva" entre o romantismo e o feminismo quanto o fez Christa Wolf. Quando nos referimos a ela como escritora romântica, não só levamos em consideração seu interesse explícito pelas escritoras românticas do início do século XIX, como Caroline von Günderrode e Bettina von Arnim, mas também, e acima de tudo, sua própria visão de mundo romântica, e a relação desta com o marxismo e com o feminismo.