Fair sharing of network resources among workflow ensembles

Cluster Computing - Computational science depends on complex, data intensive applications operating on datasets from a variety of scientific instruments. A major challenge is the integration of...     

An inertial and magnetic sensor based technique for joint angle measurement

This paper describes the design and evaluation of a miniature kinematic sensor based three dimensional (3D) joint angle measurement technique. The technique uses a combination of rate gyroscope, accelerometer and magnetometer sensor signals. The technique enables 3D inter-segment joint angle measurement and could be of benefit in a variety of applications which require monitoring of joint angles. The technique is not dependent on a fixed reference coordinate system and thus may be suitable for use in a dynamic system such as a moving vehicle. The technique was evaluated by applying it to joint angle measurement of the ankle joint. Experimental results show that accurate measurement of ankle joint angles is achieved by the technique during a variety of lower leg exercises including walking.     

Lipid biomarkers and carbon isotope signatures of a microbial (Beggiatoa) mat associated with gas hydrates in the gulf of Mexico

White and orange mats are ubiquitous on surface sediments associated with gas hydrates and cold seeps in the Gulf of Mexico. The goal of this study was to determine the predominant pathways for carbon cycling within an orange mat in Green Canyon (GC) block GC 234 in the Gulf of Mexico. Our approach incorporated laser-scanning confocal microscopy, lipid biomarkers, stable carbon isotopes, and 16S rRNA gene sequencing. Confocal microscopy showed the predominance of filamentous microorganisms (4 to 5 mum in diameter) in the mat sample, which are characteristic of Beggiatoa. The phospholipid fatty acids extracted from the mat sample were dominated by 16:1omega7c/t (67%), 18:1omega7c (17%), and 16:0 (8%), which are consistent with lipid profiles of known sulfur-oxidizing bacteria, including Beggiatoa. These results are supported by the 16S rRNA gene analysis of the mat material, which yielded sequences that are all related to the vacuolated sulfur-oxidizing bacteria, including Beggiatoa, Thioploca, and Thiomargarita. The delta13C value of total biomass was -28.6 per thousand; those of individual fatty acids were -29.4 to -33.7 per thousand. These values suggested heterotrophic growth of Beggiatoa on organic substrates that may have delta13C values characteristic of crude oil or on their by-products from microbial degradation. This study demonstrated that integrating lipid biomarkers, stable isotopes, and molecular DNA could enhance our understanding of the metabolic functions of Beggiatoa mats in sulfide-rich marine sediments associated with gas hydrates in the Gulf of Mexico and other locations.     

Microsatellite population genetics of the emerald ash borer (Agrilus planipennis Fairmaire): comparisons between Asian and North American populations

The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) (Coleoptera; Buprestidae), is an invasive wood-boring beetle native to northeast Asia. This species was first detected in Michigan USA in 2002, and is a significant threat to native and ornamental ash tree species (Fraxinus spp.) throughout North America. We characterized seven polymorphic microsatellite markers for EAB and used these to investigate EAB population structure in the early invasive populations within North America and in comparison with Asia. We found 2–9 alleles per microsatellite locus, no evidence of linkage disequilibrium, and no association with known coding sequences, suggesting that these markers are suitable for population genetic analysis. Microsatellite population genetic structure was examined in 48 EAB populations sampled between 2003 and 2008 from five regions, three in the introduced range, Michigan (US) and Ontario and Quebec (Canada) and two Asian regions, China and South Korea, where EAB is native. We found significant genetic variation geographically but not temporally in EAB populations. Bayesian clustering analyses of individual microsatellite genotypes showed strong clustering among multiple North American populations and populations in both China and South Korea. Finally, allelic richness and expected heterozygosity were higher in the native range of EAB, but there was no difference in observed heterozygosity, suggesting a significant loss of alleles upon introduction but no significant change in the distribution of alleles within and among individuals.     

An evaluation of rapid methods for monitoring vegetation characteristics of wetland bird habitat

Wetland managers benefit from monitoring data of sufficient precision and accuracy to assess wildlife habitat conditions and to evaluate and learn from past management decisions. For large-scale monitoring programs focused on waterbirds (waterfowl, wading birds, secretive marsh birds, and shorebirds), precision and accuracy of habitat measurements must be balanced with fiscal and logistic constraints. We evaluated a set of protocols for rapid, visual estimates of key waterbird habitat characteristics made from the wetland perimeter against estimates from (1) plots sampled within wetlands, and (2) cover maps made from aerial photographs. Estimated percent cover of annuals and perennials using a perimeter-based protocol fell within 10 percent of plot-based estimates, and percent cover estimates for seven vegetation height classes were within 20 % of plot-based estimates. Perimeter-based estimates of total emergent vegetation cover did not differ significantly from cover map estimates. Post-hoc analyses revealed evidence for observer effects in estimates of annual and perennial covers and vegetation height. Median time required to complete perimeter-based methods was less than 7 percent of the time needed for intensive plot-based methods. Our results show that rapid, perimeter-based assessments, which increase sample size and efficiency, provide vegetation estimates comparable to more intensive methods.