560 research outputs found
Encyclopedia of Tidepools and Rocky Shores, edited by Mark W. Denny & Steven D. Gaines, by Malcolm Ebright
Reproductive Differences among Delmarva Grass Shrimp (Palaemonetes pugio and P. vulgaris) Populations
Populations of female grass shrimps (Palaemonetes pugio and P. vulgaris) were sampled from five coastal embayments in Delaware, Maryland, and Virginia (Delmarva) and compared with respect to reproductive and life history attributes. We observed interspecific differences in timing of reproduction, carapace length, ratio of carapace length to total body length, body weight, clutch weight, clutch size, and egg volume. Onset of reproduction in P. vulgaris lagged behind P. pugio. Although there was no difference in the relationship between clutch size and carapace length for the two species, carapace length/total body length in P. pugio was greater than that in P. vulgaris. A multivariate analysis of variance indicated significant differences in carapace length, clutch weight, body weight, clutch size, and egg volume attributable to effects of species, population, and interactions between them. At all sites, P. pugio produced larger eggs than P. vulgaris. Although the two species did not differ in reproductive effort, both species exhibited increases in reproductive effort with latitude. Clutch size also tended to increase with latitude for both species. In populations where both species were abundant, adult females of P. pugio were longer and heavier and produced heavier egg masses comprised of fewer, larger eggs
Solutions Network Formulation Report. Aerosol Polarimetry Sensor Measurements of Diffuse-to-Global Irradiance Ratio for Improved Forecasting of Plant Productivity and Health
Studies have shown that vegetation is directly sensitive to changes in the diffuse-to-global irradiance ratio and that increased percentage of diffuse irradiation can accelerate photosynthesis. Therefore, measurements of diffuse versus global irradiance could be useful for monitoring crop productivity and overall vegetative health as they relate to the total amount of particulates in the air that result from natural disasters or anthropogenic (manmade) causes. While the components of solar irradiance are measured by satellite and surface sensors and calculated with atmospheric models, disagreement exists between the results, creating a need for more accurate and comprehensive retrievals of atmospheric aerosol parameters. Two satellite sensors--APS and VIIRS--show promise for retrieving aerosol properties at an unprecedented level of accuracy. APS is expected to be launched in December 2008. The planned launch date for VIIRS onboard NPP is September 2009. Identified partners include the USDA s ARS, North Carolina State University, Purdue Climate Change Research Center, and the Cooperative Institute for Research in the Atmosphere at Colorado State University. Although at present no formal DSSs (decision support systems) require accurate values of diffuse-to-global irradiance, this parameter is sufficiently important that models are being developed that will incorporate these measurements. This candidate solution is aligned with the Agricultural Efficiency and Air Quality National Applications
Forecasting Plant Productivity and Health Using Diffuse-to-Global Irradiance Ratios Extracted from the OMI Aerosol Product
Atmospheric aerosols are a major contributor to diffuse irradiance. This Candidate Solution suggests using the OMI (Ozone Monitoring Instrument) aerosol product as input into a radiative transfer model, which would calculate the ratio of diffuse to global irradiance at the Earth s surface. This ratio can significantly influence the rate of photosynthesis in plants; increasing the ratio of diffuse to global irradiance can accelerate photosynthesis, resulting in greater plant productivity. Accurate values of this ratio could be useful in predicting crop productivity, thereby improving forecasts of regional food resources. However, disagreements exist between diffuse-to-global irradiance values measured by different satellites and ground sensors. OMI, with its unique combination of spectral bands, high resolution, and daily global coverage, may be able to provide more accurate aerosol measurements than other comparable sensors
Teaching interdisciplinary sustainability science teamwork skills to graduate students using in-person and web-based interactions
Interdisciplinary sustainability science teamwork skills are essential for addressing the world’s most pressing and complex sustainability problems, which inherently have social, natural, and engineering science dimensions. Further, because sustainability science problems exist at global scales, interdisciplinary science teams will need to consist of international members who communicate and work together effectively. Students trained in international interdisciplinary science skills will be able to hit the ground running when they obtain jobs requiring them to tackle sustainability problems. While many universities now have sustainability science programs, few offer courses that are interdisciplinary and international in scope. In the fall semester of 2013, we piloted a course for graduate students entitled “Principles of Interdisciplinary Sustainability Research” at Michigan Technological University. This course was part of our United States National Science Foundation Partnerships in International Research and Education project on bioenergy development impacts across the Americas. In this case study, we describe the course development and implementation, share critical insights from our experience teaching the course and student learning outcomes, and give recommendations for future similar course
Recent Legal Literature
Anson: Principles of the English Law of Contract; Heseltine: A Digest of the Law of Trade-Marks and Unfair Trade; Abbott: A Treatise on the Law of Municipal Corporations; Alderson: A Practical Treatise on the Law of Receivers as applicable to Individuals, Partnerships and Corporations, with extended consideration of receivers of railways and in proceedings in bankruptc
White Matter Abnormalities in Patients with Treatment-Resistant Genetic Generalized Epilepsies.
BACKGROUND Genetic generalized epilepsies (GGEs) are associated with microstructural brain abnormalities that can be evaluated with diffusion tensor imaging (DTI). Available studies on GGEs have conflicting results. Our primary goal was to compare the white matter structure in a cohort of patients with video/EEG-confirmed GGEs to healthy controls (HCs). Our secondary goal was to assess the potential effect of age at GGE onset on the white matter structure. MATERIAL AND METHODS A convenience sample of 23 patients with well-characterized treatment-resistant GGEs (13 female) was compared to 23 HCs. All participants received MRI at 3T. DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), were compared between groups using Tract-Based Spatial Statistics (TBSS). RESULTS After controlling for differences between groups, abnormalities in DTI parameters were observed in patients with GGEs, including decreases in functional anisotropy (FA) in the hemispheric (left>right) and brain stem white matter. The examination of the effect of age at GGE onset on the white matter integrity revealed a significant negative correlation in the left parietal white matter region FA (R=-0.504; p=0.017); similar trends were observed in the white matter underlying left motor cortex (R=-0.357; p=0.103) and left posterior limb of the internal capsule (R=-0.319; p=0.148). CONCLUSIONS Our study confirms the presence of widespread white matter abnormalities in patients with GGEs and provides evidence that the age at GGE onset may have an important effect on white matter integrity
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Excretion of Antibiotic Resistance Genes by Dairy Calves Fed Milk Replacers with Varying Doses of Antibiotics
Elevated levels of antibiotic resistance genes (ARGs) in soil and water have been linked to livestock farms and in some cases feed antibiotics may select for antibiotic resistant gut microbiota. The purpose of this study was to examine the establishment of ARGs in the feces of calves receiving milk replacer containing no antibiotics versus subtherapeutic or therapeutic doses of tetracycline and neomycin. The effect of antibiotics on calf health was also of interest. Twenty-eight male and female dairy calves were assigned to one of the three antibiotic treatment groups at birth and fecal samples were collected at weeks 6, 7 (prior to weaning), and 12 (5 weeks after weaning). ARGs corresponding to the tetracycline (tetC, tetG, tetO, tetW, and tetX), macrolide (ermB, ermF), and sulfonamide (sul1, sul2) classes of antibiotics along with the class I integron gene, intI1, were monitored by quantitative polymerase chain reaction as potential indicators of direct selection, co-selection, or horizontal gene transfer of ARGs. Surprisingly, there was no significant effect of antibiotic treatment on the absolute abundance (gene copies per gram wet manure) of any of the ARGs except ermF, which was lower in the antibiotic-treated calf manure, presumably because a significant portion of host bacterial cells carrying ermF were not resistant to tetracycline or neomycin. However, relative abundance (gene copies normalized to 16S rRNA genes) of tetO was higher in calves fed the highest dose of antibiotic than in the other treatments. All genes, except tetC and intI1, were detectable in feces from 6 weeks onward, and tetW and tetG significantly increased (P < 0.10), even in control calves. Overall, the results provide new insight into the colonization of calf gut flora with ARGs in the early weeks. Although feed antibiotics exerted little effect on the ARGs monitored in this study, the fact that they also provided no health benefit suggests that the greater than conventional nutritional intake applied in this study overrides previously reported health benefits of antibiotics. The results suggest potential benefit of broader management strategies, and that cost and risk may be avoided by minimizing incorporation of antibiotics in milk replacer
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