18 research outputs found

    The Southern Ocean Exchange: Porous boundaries between humpback whale breeding populations in southern polar waters

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    Humpback whales (Megaptera novaeangliae) are a cosmopolitan species and perform long annual migrations between low-latitude breeding areas and high-latitude feeding areas. Their breeding populations appear to be spatially and genetically segregated due to long-term, maternally inherited fidelity to natal breeding areas. In the Southern Hemisphere, some humpback whale breeding populations mix in Southern Ocean waters in summer, but very little movement between Pacific and Atlantic waters has been identified to date, suggesting these waters constituted an oceanic boundary between genetically distinct populations. Here, we present new evidence of summer co-occurrence in the West Antarctic Peninsula feeding area of two recovering humpback whale breeding populations from the Atlantic (Brazil) and Pacific (Central and South America). As humpback whale populations recover, observations like this point to the need to revise our perceptions of boundaries between stocks, particularly on high latitude feeding grounds. We suggest that this “Southern Ocean Exchange” may become more frequent as populations recover from commercial whaling and climate change modifies environmental dynamics and humpback whale prey availability

    Levedura hidrolisada como fonte de nucleotídeos para leitões recém-desmamados Hydrolyzed yeast as source of nucleotides for weanling pigs

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    Com este trabalho objetivou-se avaliar os efeitos de níveis de nucleotídeos em dietas para leitões recém-desmamados sobre o desempenho, a morfometria de órgãos e a histologia do epitélio intestinal. Foram utilizados 144 leitões desmamados aos 21 dias de idade e com peso médio inicial de 5,80 ± 0,16 kg em um experimento inteiramente ao acaso, com seis dietas, seis repetições por dieta e quatro animais por baia (unidade experimental). As dietas foram: Am (antimicrobiano) _ dieta basal com inclusão de 40 ppm de sulfato de colistina, assim como dieta basal contendo 0, 150, 300, 450 e 600 ppm de nucleotídeos. Ao final do experimento, foi abatido um animal de cada baia para coleta das amostras e avaliação da morfometria de órgãos e da histologia do epitélio intestinal. No período de 1 a 14 dias de experimentação, houve piora linear das características de desempenho e, no período total de 34 dias, redução linear do peso final dos animais com o aumento dos níveis de nucleotídeos na dieta. Os leitões alimentados com a dieta contendo colistina apresentaram maior comprimento do intestino delgado e menor relação altura de vilosidade:profundidade de cripta (AV:PC) no duodeno em comparação àqueles que receberam nucleotídeos. Foram observados, também, aumento linear no peso relativo do baço e na relação AV:PC e redução linear da profundidade de cripta no duodeno dos animais com a adição de nucleotídeos na dieta. Assim, embora não tenha promovido melhora no desempenho, a adição de até 600 ppm de nucleotídeos em dietas complexas melhora a morfometria de órgãos e a histologia do epitélio intestinal de leitões recém-desmamados.<br>The objective of this work was to evaluate the effects of levels of nucleotides in diets for weanling pigs on performance, organs morphometry and histology of intestinal epithelium. One hundred and forty-four pigs weaned at 21 days of age and with 5.80 ± 0.16 kg initial live weight were used in a completely randomized experimental design with six diets, six replications per diet and four animals per pen (experimental unit). Diets were: Am _ antimicrobial: basal diet with 40 ppm of colistin sulfate and basal diet with 0, 150, 300, 450 and 600 ppm of nucleotides. At the end of the experimental period, one animal of each pen was slaughtered to evaluate morphometry of the organs and intestinal epithelium histology. From day 1 to day 14 of the experimental period, performance traits worsened linearly and for the total experimental period of 34 days, a linear reduction of final live weight was observed when levels of dietary nucleotides were increased. Pigs fed diet with colistin showed greater length of small intestine and lower villus height:crypt depth ratio (AV:PC) of duodenum when compard to those fed nucleotides. Also, a linear increase of relative weight of spleen, as well as a linear increase of AV:PC and linear reduction of crypt depth of duodenum were observed with the addition of nucleotides in the diet. Therefore, although the addition up to 600 ppm of nucleotides in complex diets did not improve performance, it improves morphometry of the organs and intestinal epithelium histology of weanling pigs

    Euclid. I. Overview of the Euclid mission

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    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Euclid. I. Overview of the Euclid mission

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    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Euclid. I. Overview of the Euclid mission

    No full text
    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Euclid. I. Overview of the Euclid mission

    No full text
    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance

    Euclid. I. Overview of the Euclid mission

    No full text
    International audienceThe current standard model of cosmology successfully describes a variety of measurements, but the nature of its main ingredients, dark matter and dark energy, remains unknown. Euclid is a medium-class mission in the Cosmic Vision 2015-2025 programme of the European Space Agency (ESA) that will provide high-resolution optical imaging, as well as near-infrared imaging and spectroscopy, over about 14,000 deg^2 of extragalactic sky. In addition to accurate weak lensing and clustering measurements that probe structure formation over half of the age of the Universe, its primary probes for cosmology, these exquisite data will enable a wide range of science. This paper provides a high-level overview of the mission, summarising the survey characteristics, the various data-processing steps, and data products. We also highlight the main science objectives and expected performance
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