15 research outputs found
Pervasive gaps in Amazonian ecological research
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
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
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Still searching for graves: an analytical strategy for interpreting geophysical data used in the search for “unmarked” graves
Searching for and mapping the physical extent of unmarked graves using geophysical techniques has proven difficult in many cases. The success of individual geophysical techniques for detecting graves depends on a site-by-site basis. Significantly, detection of graves often results from measured contrasts that are linked to the background soils rather than the type of archaeological feature associated with the grave. It is evident that investigation of buried remains should be considered within a 3D space as the variation in burial environment can be extremely varied through the grave. Within this paper, we demonstrate the need for a multi-method survey strategy to investigate unmarked graves, as applied at a “planned” but unmarked pauper’s cemetery. The outcome from this case study provides new insights into the strategy that is required at such sites. Perhaps the most significant conclusion is that unmarked graves are best understood in terms of characterization rather than identification. In this paper, we argue for a methodological approach that, while following the current trends to use multiple techniques, is fundamentally dependent on a structured approach to the analysis of the data. The ramifications of this case study illustrate the necessity of an integrated strategy to provide a more holistic understanding of unmarked graves that may help aid in management of these unseen but important aspects of our heritage. It is concluded that the search for graves is still a current debate and one that will be solved by methodological rather than technique-based arguments
Fungos aerĂłbios no intestino grosso de borregos e de ovelhas criados em pastagens tropicais
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