145 research outputs found
NASA Glenn high temperature EB-coated CVI SiC/SiC minicomposite testing and characterization
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The current status of advanced environmentanl barrier coatings for ceramic matrix composites at NASA
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Prospectus, February 11, 1987
https://spark.parkland.edu/prospectus_1987/1004/thumbnail.jp
Trawl Exposure and Protection of Seabed Fauna at Large Spatial Scales
Aim: Trawling is the most widespread direct human disturbance on the seabed. Knowledge of the extent and consequences of this disturbance is limited because large-scale distributions of seabed fauna are not well known. We map faunal distributions in the Australian Exclusive Economic Zone (EEZ) and quantify the proportion of their abundance that occurs in areas 1) that are directly trawled and 2) where legislation permanently prohibits trawling—defined as percentage exposure or protection, respectively. Our approach includes developing a method that integrates data from disparate seabed surveys to spatially expand predicted benthos distributions. Location: Australia. Methods : We collate data from 18 seabed surveys to map the distribution of seabed invertebrates (benthos) in nine regions. Our approach combines data from multiple surveys, groups taxa within taxonomic classes and uses Random Forests to predict spatial abundance distributions of benthos groups from environmental variables. Exposure and protection of benthos groups were quantified by mapping their predicted abundance distributions against the footprint of trawling and legislated boundaries of marine reserves and fishery closures. Results: Trawling is currently prohibited from more area of Australia's EEZ (58%) than is trawled (<5%). Across 134 benthos groups, 96% had greater protection of abundance than exposure. The mean trawl exposure of benthos-group abundance was 7%, compared to mean protection of 38%, whereas the mean abundance neither trawled nor protected was 55%. Fishery closures covered 19% less study area than marine reserves, but overlapped with a higher proportion (5% more) of benthos-group abundance. Main Conclusions: This study provides the most extensive quantitative assessment of the current exposure of Australia's benthos to trawling. Further, it highlights the contribution of fishery closures to marine conservation. These results help identify regions and taxa that are at greatest potential risk from trawling and support managers to achieve balance between conservation and sustainable industries in marine ecosystems
The Structure of Episodic Memory: Ganeri's ‘Mental Time Travel and Attention’
We offer a framework for assessing what the structure of episodic memory might be, if one accepts the Buddhist denial of persisting selves. This paper is a response to Jonardon Ganeri's paper "Mental time travel and attention", which explores Buddhaghosa's ideas about memory. (It will eventually be published with a reply by Ganeri)
Trawl fishing impacts on the status of seabed fauna in diverse regions of the globe
Bottom trawl fishing is a controversial activity. It yields about a quarter of the world's wild seafood, but also has impacts on the marine environment. Recent advances have quantified and improved understanding of large-scale impacts of trawling on the seabed. However, such information needs to be coupled with distributions of benthic invertebrates (benthos) to assess whether these populations are being sustained under current trawling regimes. This study collated data from 13 diverse regions of the globe spanning four continents. Within each region, we combined trawl intensity distributions and predicted abundance distributions of benthos groups with impact and recovery parameters for taxonomic classes in a risk assessment model to estimate benthos status. The exposure of 220 predicted benthos-group distributions to trawling intensity (as swept area ratio) ranged between 0% and 210% (mean = 37%) of abundance. However, benthos status, an indicator of the depleted abundance under chronic trawling pressure as a proportion of untrawled state, ranged between 0.86 and 1 (mean = 0.99), with 78% of benthos groups > 0.95. Mean benthos status was lowest in regions of Europe and Africa, and for taxonomic classes Bivalvia and Gastropoda. Our results demonstrate that while spatial overlap studies can help infer general patterns of potential risk, actual risks cannot be evaluated without using an assessment model that incorporates trawl impact and recovery metrics. These quantitative outputs are essential for sustainability assessments, and together with reference points and thresholds, can help managers ensure use of the marine environment is sustainable under the ecosystem approach to management
A Prospective Three-Year Cohort Study of the Epidemiology and Virology of Acute Respiratory Infections of Children in Rural India
Acute respiratory infection (ARI) is a major killer of children in developing countries. Although the frequency of ARI is similar in both developed and developing countries, mortality due to ARI is 10-50 times higher in developing countries. Viruses are common causes of ARI among such children, yet the disease burden of these infections in rural communities is unknown.A prospective longitudinal study was carried out in children enrolled from two rural Indian villages at birth and followed weekly for the development of ARI, classified as upper respiratory infection, acute lower respiratory infection (ALRI), or severe ALRI. Respiratory syncytial virus (RSV), influenza, parainfluenza viruses and adenoviruses in nasopharyngeal aspirates were detected by direct fluorescent antibody testing (DFA) and, in addition, centrifugation enhanced culture for RSV was done. 281 infants enrolled in 39 months and followed until 42 months. During 440 child years of follow-up there were 1307 ARIs, including 236 ALRIs and 19 severe ALRIs. Virus specific incidence rates per 1000 child years for RSV were total ARI 234, ALRI 39, and severe ALRI 9; for influenza A total ARI 141, ALRI 39; for INF B total ARI 37; for PIV1 total ARI 23, for PIV2 total ARI 28, ALRI 5; for parainfluenza virus 3 total ARI 229, ALRI 48, and severe ALRI 5 and for adenovirus total ARI 18, ALRI 5. Repeat infections with RSV were seen in 18 children.RSV, influenza A and parainfluenza virus 3 were important causes of ARI among children in rural communities in India. These data will be useful for vaccine design, development and implementation purposes
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