37 research outputs found

    Propellant/material compatibility program and results: Ten-year milestones

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    The analyses and results of a test program to establish the effects of long term (10 years or more) contact of materials with earth-storable propellants for the purpose of designing chemical propulsion system components which are used for current as well as future planetary spacecraft are described. The period from the publication of JPL TM 33-779 IN 1976 through the testing accomplished in 1981 is covered. The following propellants are reported herein: hydrazine, monomethylhydrazine and nitrogen tetroxide. Materials included the following: aluminum alloys, corrosion resistant steels and a titanium alloy. The results of the testing of more than 80 specimens are included. Material ratings relative to the ten year milepost were assigned. Some evidence of propellant decomposition was found. Titanium is rated as acceptable for ten year applications. Aluminum and stainless steel alloys are also rated as acceptable with few restrictions

    Aerial thermal scanner data for monitoring rooftop temperatures

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    Four Nebraska communities and one South Dakota community were surveyed. Thermal scanner data were converted to a film format and the resultant imagery was successfully employed to monitor rooftop temperatures. The program places emphasis on heat losses resulting from inadequate home insulation, offers CENGAS customers the opportunity to observe a thermogram of their rooftop, and assists homeowners in evaluating insulation needs

    Characterizing Fishing Effort and Spatial Extent of Coastal Fisheries

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    Biodiverse coastal zones are often areas of intense fishing pressure due to the high relative density of fishing capacity in these nearshore regions. Although overcapacity is one of the central challenges to fisheries sustainability in coastal zones, accurate estimates of fishing pressure in coastal zones are limited, hampering the assessment of the direct and collateral impacts (e.g., habitat degradation, bycatch) of fishing. We compiled a comprehensive database of fishing effort metrics and the corresponding spatial limits of fisheries and used a spatial analysis program (FEET) to map fishing effort density (measured as boat-meters per km2) in the coastal zones of six ocean regions. We also considered the utility of a number of socioeconomic variables as indicators of fishing pressure at the national level; fishing density increased as a function of population size and decreased as a function of coastline length. Our mapping exercise points to intra and interregional ‘hotspots’ of coastal fishing pressure. The significant and intuitive relationships we found between fishing density and population size and coastline length may help with coarse regional characterizations of fishing pressure. However, spatially-delimited fishing effort data are needed to accurately map fishing hotspots, i.e., areas of intense fishing activity. We suggest that estimates of fishing effort, not just target catch or yield, serve as a necessary measure of fishing activity, which is a key link to evaluating sustainability and environmental impacts of coastal fisheries

    Large-scale Molecular Diet Analysis in a Generalist Marine Mammal Reveals Male Preference for Prey of Conservation Concern

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    Sex-specific diet information is important in the determination of predator impacts on prey populations. Unfortunately, the diet of males and females can be difficult to describe, particularly when they are marine predators. We combined two molecular techniques to describe haul-out use and prey preferences of male and female harbor seals (Phoca vitulina) from Comox and Cowichan Bay (Canada) during 2012-2013. DNA metabarcoding quantified the diet proportions comprised of prey species in harbor seal scat, and qPCR determined the sex of the individual that deposited each scat. Using 287 female and 260 male samples, we compared the monthly sex ratio with GLMs and analyzed prey consumption relative to sex, season, site, and year with PERMANOVA. The sex ratio between monthly samples differed widely in both years (range = 12%-79% males) and showed different patterns at each haul-out site. Male and female diet differed across both years and sites: Females consumed a high proportion of demersal fish species while males consumed more salmonid species. Diet composition was related to both sex and season (PERMANOVA: R 2 = 27%, p \u3c 0.001; R 2 = 24%, p \u3c 0.001, respectively) and their interaction (PERMANOVA: R 2 = 11%, p \u3c 0.001). Diet differences between males and females were consistent across site and year, suggesting fundamental foraging differences, including that males may have a larger impact on salmonids than females. Our novel combination of techniques allowed for both prey taxonomic and spatiotemporal resolution unprecedented in marine predators

    Autoantibodies to muscarinic acetylcholine receptors found in patients with primary biliary cirrhosis

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    <p>Abstract</p> <p>Background</p> <p>Autoantibodies to the human muscarinic acetylcholine receptor of the M3 type (hmAchR M3) have been suggested to play an etiopathogenic role in Sjögren's syndrome. Primary biliary cirrhosis (PBC) often is associated with this syndrome. Therefore, we studied the co-presence of hmAchR M3 autoantibodies in patients with PBC.</p> <p>Methods</p> <p>Frequency of hmAchR M3 autoantibodies was assessed by Western blotting analysis as well as by an ELISA using a 25-mer peptide of the 2<sup>nd </sup>extracellular loop of hmAchR M3. Co-localization of hmAchR M3/PBC-specific autoantibodies was studied by confocal laser scanning microscopy. Finally, sera from patients with PBC as well as from healthy controls were tested.</p> <p>Results</p> <p>Western blotting analysis as well as results from ELISA testing revealed a significantly enhanced IgG reactivity in PBC patients in contrast to healthy controls. Co-localization of autoantibodies with the hmAchR M3 receptor-specific autoantibodies was observed in 10 out of 12 PBC-patients but none of the 5 healthy controls. Antibodies of the IgM type were not found to be affected.</p> <p>Conclusions</p> <p>For the first time, our data demonstrate the presence of autoantibodies to the hmAchR M3 in PBC patients. These findings might contribute to the understanding of the pathogenesis of this disease. Further studies have to focus on the functionality of hmAchR M3 autoantibodies in PBC patients.</p

    2006. Eighteen years of saturation tagging data reveal a significant increase in nesting hawksbill sea turtles (Eretmochelys imbricata) on Long Island, Antigua. Animal Conservation

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    Abstract Hawksbill sea turtle Eretmochelys imbricata nesting on Long Island, Antigua, West Indies (also known as Jumby Bay) has been monitored since 1987. Although the numbers of nesting females remained relatively constant for the first 11 survey seasons (1987)(1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997), inclusion of more recent data (1998)(1999)(2000)(2001)(2002)(2003)(2004) in the analysis reveals a statistically significant upward trend. In particular, neophytes have shown a significant upturn in numbers, whereas the remigrant subpopulation has remained stationary. This indicates that recruitment is driving the upward trend in the total number of nesters. Predictive models based on the Poisson distribution suggest that the neophyte subpopulation will continue to grow in size by an average of 10% per annum. Model-based predictions and their limitations are discussed. The Jumby Bay Hawksbill Project, which has monitored and protected nesting hawksbills and their eggs since the project&apos;s onset, is one among several factors that may contribute to the recent increase in nesting females

    A regional analysis of coastal and domestic fishing effort in the wider Caribbean

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    Although regulated fishing effort is relatively well documented for fisheries in developed states, developing countries are dominated by artisanal fisheries that are characterized by large numbers of small boats, fishing in dispersed and remote locations. These factors make quantifying artisanal fishing effort difficult. In this study, we examined the distribution and density of fishing effort across a region dominated by coastal, artisanal fisheries: the wider Caribbean. We used generalized linear regression models to predict missing data needed to compute fishing effort metrics and to explain variance in average boat length of a fishery and the number of small-scale boats in a given country. Clear intra-regional differences between mainland and island fisheries, and between northern and southern Caribbean fisheries, are evident in the results. To map artisanal fisheries based on the minimal data available, we created a free, automated Fishing Effort Envelope Tool (FEET). Through the use of this tool, we mapped all fisheries in the Caribbean to the extent possible given current data. Further, this mapping process also allowed us to identify hotspots of high density coastal fishing and data gaps that may mask areas of even higher fishing pressure. The potential ecological consequences of the scale of artisanal fishing are profound, and have greater implications for developing regions worldwide
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