1,008 research outputs found

    A mastite em ovinos de corte afeta os ganhos de peso dos cordeiros?.

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    O Brasil possui um rebanho ovino de aproximadamente quinze milhões de animais que apresenta tendência de crescimento devido à elevação da demanda e consequente valorização da carne, o que torna a ovinocultura de corte uma atividade lucrativa. A preocupação com a mastite aumentou em relação a rebanhos destinados à produção de carne, pelo descarte prematuro das ovelhas com anormalidades de úbere e a redução do ganho de peso diário (GPD) das crias. A forma subclínica da doença pode acarretar menor taxa de crescimento e maior mortalidade dos cordeiros, pela redução da concentração de imunoglobulinas no soro e da produção de leite. Este trabalho teve como objetivo comparar os GPDs de animais oriundos de mães sadias com GPDs de crias de mães doentes em dois rebanhos localizados no Estado de São Paulo

    Interaction between lactose and cadmium chloride in aqueous solutions as seen by diffusion coefficients measurements

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    Diffusion coefficients of an aqueous system containing cadmium chloride 0.100 mol · dm−3 and lactose at different concentrations at 25 °C have been measured, using a conductimetric cell and an automatic apparatus to follow diffusion. The cell relies on an open-ended capillary method and a conductimetric technique is used to follow the diffusion process by measuring the resistance of a solution inside the capillaries, at recorded times. From these results and by ab initio calculations, it was possible to obtain a better understanding of the effect of lactose on transport of cadmium chloride in aqueous solutions

    Chemical Characterization and Source Apportionment of Household Fine Particulate Matter in Rural, Peri-urban, and Urban West Africa

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    Household air pollution in sub-Saharan Africa and other developing regions is an important cause of disease burden. Little is known about the chemical composition and sources of household air pollution in sub-Saharan Africa, and how they differ between rural and urban homes. We analyzed the chemical composition and sources of fine particles (PM2.5) in household cooking areas of multiple neighborhoods in Accra, Ghana, and in peri-urban (Banjul) and rural (Basse) areas in The Gambia. In Accra, biomass burning accounted for 39–62% of total PM2.5 mass in the cooking area in different neighborhoods; the absolute contributions were 10–45 μg/m3. Road dust and vehicle emissions comprised 12–33% of PM2.5 mass. Solid waste burning was also a significant contributor to household PM2.5 in a low-income neighborhood but not for those living in better-off areas. In Banjul and Basse, biomass burning was the single dominant source of cooking-area PM2.5, accounting for 74–87% of its total mass; the relative and absolute contributions of biomass smoke to PM2.5 mass were larger in households that used firewood than in those using charcoal, reaching as high as 463 μg/m3 in Basse homes that used firewood for cooking. Our findings demonstrate the need for policies that enhance access to cleaner fuels in both rural and urban areas, and for controlling traffic emissions in cities in sub-Saharan Africa

    Estafilococos resistentes à oxacilina isolados em casos de mastite subclínica em ovinos.

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    Bactérias do gênero Staphylococcus estão entre os principais agentes causadores da mastite ovina. Um dos maiores entraves ao tratamento dos animais doentes são cepas resistentes aos antimicrobianos empregados. A pesquisa do gene mecA nos estafilococos é um instrumento auxiliar para a determinação de aspectos epidemiológicos da doença. Este trabalho teve por objetivo investigar a resistência à oxacilina em estafilococos coagulase-negativos isolados no leite de ovelhas com mastite subclínica. Foram analisadas 448 amostras de leite de dois rebanhos. Os micro-organismos isolados foram submetidos previamente a testes de sensibilidade a antibióticos in vitro a partir da técnica de difusão em disco. Naqueles resistentes à oxacilina nestes testes efetuou-se a pesquisa do gene mecA, com a extração do DNA cromossômico por meio da técnica de extração fenol-clorofórmio. Os estafilococos coagulase-negativos apresentaram resistência à oxacilina e a presença do gene mecA foi detectada em quatro isolados, que também apresentaram características de multirresistência. Tais achados reforçam a importância deste grupo de micro-organismos na etiologia da mastite subclínica em ovinos e abre perspectivas para futuras pesquisas para a investigação da epidemiologia da doença

    A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe.

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    Elasmobranchs represent important components of marine ecosystems, but they can be vulnerable to overexploitation. This has driven investigations into the population genetic structure of large-bodied pelagic sharks, but relatively little is known of population structure in smaller demersal taxa, which are perhaps more representative of the biodiversity of the group. This study explores spatial population genetic structure of the small-spotted catshark (Scyliorhinus canicula), across European seas. The results show significant genetic differences among most of the Mediterranean sample collections, but no significant structure among Atlantic shelf areas. The data suggest the Mediterranean populations are likely to have persisted in a stable and structured environment during Pleistocene sea-level changes. Conversely, the Northeast Atlantic populations would have experienced major changes in habitat availability during glacial cycles, driving patterns of population reduction and expansion. The data also provide evidence of male-biased dispersal and female philopatry over large spatial scales, implying complex sex-determined differences in the behaviour of elasmobranchs. On the basis of this evidence, we suggest that patterns of connectivity are determined by trends of past habitat stability that provides opportunity for local adaptation in species exhibiting philopatric behaviour, implying that resilience of populations to fisheries and other stressors may differ across the range of species
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