15 research outputs found

    Pervasive gaps in Amazonian ecological research

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    Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

    The thermal performance of fuel matrix material in a CO2 atmosphere

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    The thermal oxidation performance of a semi-graphitic fuel matrix-material has been compared to two grades of nuclear graphite between 600 C and 1200 C in flowing CO2. Fuel matrix material is used to produce compacts or pebbles containing TRISO coated particle fuel for High Temperature Reactors (HTRs). The A3-27 fuel matrix-material grade was compared to NBG-18 and Gilsocarbon nuclear graphite grades. At 1200 C temperatures A3-27 appears to be more reactive than NBG-18, but less so than Gilsocarbon. At 600 C the oxidation rate of A3-27 is comparable to that of NBG-18, but both are significantly higher than that of Gilsocarbon. It is concluded that the comparable thermal oxidation behaviour of graphite and fuel-matrix material suggests that operating temperatures in a CO2 cooled reactor fuelled with TRISO coated particle fuel would not need to be reduced below those considered acceptable for the use of nuclear graphite. © 2013 The Authors. Published by Elsevier B.V. All rights reserved

    Fungos aerĂłbios no intestino grosso de borregos e de ovelhas criados em pastagens tropicais

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    Fungi populations were evaluated in large intestine from sheep raised in the North of Minas Gerais, Brazil. The samples were from 39 Santa InĂŞs crossbred ewes and 30 lambs raised on Tanzania grass (Panicum maximum cv. Tanzania), both supplemented with mineral mixtures. The clinical specimens were directly collected from rectal ampoule with sterile swabs. The development of fungal mycelium was observed in all lamb samples and positive cultures were observed in 34 ewe specimens (87.2%). After microculture of 40 colonies from lambs, 34 isolates of the genus Aspergillus, three of Paecilomyces spp., one Acremonium sp., and one Trichoderma sp. were identified. Out of the 39 isolates from ewes, 15 Paecilomyces spp., 11 Aspergillus spp., 11 Malbranchea spp., and one Onychocola sp. were identified. The results showed the predominance of the genus Aspergillus in the lambs, while the genus Paecilomyces, Malbranchea, and Aspergillus were predominant, in ewes
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