5,794 research outputs found
Goldstone radio spectrum protection
Potential electromagnetic interference to the Goldstone tracking receivers due to neighboring military installations is discussed. Coordination of the military and NASA Goldstone activities in the Mojave Desert area is seen to be an effective method to protect the Goldstone radio spectrum while maintaining compatible operations for the military and Goldstone
Lie Groups and mechanics: an introduction
The aim of this paper is to present aspects of the use of Lie groups in
mechanics. We start with the motion of the rigid body for which the main
concepts are extracted. In a second part, we extend the theory for an arbitrary
Lie group and in a third section we apply these methods for the diffeomorphism
group of the circle with two particular examples: the Burger equation and the
Camassa-Holm equation
Associations of Abdominal Muscle Area and Radiodensity with Adiponectin and Leptin: The Multiethnic Study of Atherosclerosis.
ObjectiveThis study examined the associations of muscle area and radiodensity with adiponectin and leptin.MethodsA total of 1,944 participants who enrolled in the Multi-Ethnic Study of Atherosclerosis underwent computed tomography to quantify body composition and measurements of adiponectin, leptin, interleukin-6, C-reactive protein, and resistin.ResultsThe mean age and BMI of participants were 64.7 years and 28.1 kg/m2 and 49% were female. With adjustment for age, gender, race/ethnicity, traditional cardiovascular disease risk factors, inflammatory biomarkers, physical activity, and sedentary behavior, a 1-SD increment in total abdominal, stability, and locomotor muscle area was associated with a 19%, 17%, and 12% lower adiponectin level, respectively (P < 0.01 for all) but not leptin (P > 0.05). Muscle radiodensity was more robustly associated with adiponectin and leptin in the multivariable linear regression models. That is, with full adjustment for all covariates, a 1-SD increment in total abdominal, stability, and locomotor muscle radiodensity was associated with a 31%, 31%, and 18% lower adiponectin level (P < 0.01 for all) and a 6.7%, 4.6%, and 8.1% higher leptin level (P < 0.05 for all), respectively.ConclusionsThe data suggest that increases in muscle area and radiodensity may have positive impacts on chronic inflammation and, in turn, reduce the risk of cardiometabolic disease
PHYSIOLOGY AND ENDOCRINOLOGY SYMPOSIUM: The current status of heat shock in early embryonic survival and reproductive effi ciency
The Physiology and Endocrinology Symposium titled “The Current Status of Heat Shock in Early Embryonic Survival and Reproductive Efficiency” was held at the Joint Annual Meeting in Phoenix, AZ, July 15 to 19, 2012. In recent years, data has accumulated indicating a role for heat shock proteins (HSP) in early embryonic development and reproductive efficiency. An understanding of how these proteins influence reproductive efficiency both in vivo and in vitro could have major ramifications for production agriculture. In cattle, performance differences have been identified in Bos indicus breeds and genetic polymorphisms in HSP70 have been associated with reproductive performance (Rosenkrans et al., 2010). In Holstein cows, differences in expression of genes in the HSP40 family have been associated with improved early embryonic development in vitro, indicating that these proteins may have a greater role in reproductive efficiency than thought, even in animals not adapted to a tropical environment and not placed in a heat stress situation (Zhang et al., 2011). The speakers at this Physiology and Endocrinology Symposium were identified to address these topics based on their research
Mapping Landscape Resistance to Identify Corridors and Barriers for Elephant Movement in Southern Africa
Mapping Landscape Resistance to Identify Corridors and Barriers for Elephant Movement in Southern Africa ..
Lightside Atmospheric Revitalization System
The system was studied as a replacement to the present baseline LiOH system for extended duration shuttle missions. The system consists of three subsystems: a solid amine water desorbed regenerable carbon dioxide removal system, a water vapor electrolysis oxygen generating system, and a Sabatier reactor carbon dioxide reduction system. The system is designed for use on a solar powered shuttle vehicle. The majority of the system's power requirements are utilized on the Sun side of each orbit, when solar power is available
Spatially-explicit estimation of Wright's neighborhood size in continuous populations
Effective population size (Ne) is an important parameter in conservation genetics because it quantifies a population’s capacity to resist loss of genetic diversity due to inbreeding and drift. The classical approach to estimate Ne from genetic data involves grouping sampled individuals into discretely defined subpopulations assumed to be panmictic. Importantly, this assumption does not capture the continuous nature of populations genetically isolated by distance. Alternative approaches based on Wright’s genetic neighborhood concept quantify the local number of breeding individuals (NS) in a continuous population (as opposed to the global Ne). However, they do not reflect the potential for NS to vary spatially nor do they account for the resistance of a heterogeneous landscape to gene flow (isolation by resistance). Here, we describe an application of Wright’s neighborhood concept that provides spatially-explicit estimates of local NS from genetic data in continuous populations isolated by distance or resistance. We delineated local neighborhoods surrounding each sampled individual based on sigma (), a measure of the local extent of breeding. When was known, the linkage disequilibrium method applied to local neighborhoods produced unbiased estimates of NS that were highly variable across the landscape. NS near the periphery or areas surrounded by high resistance was as much as an order of magnitude lower compared to the center, raising the potential for a spatial component to extinction vortex dynamics in continuous populations. When is not known, it may be estimated from genetic data, but two methods we evaluated identified analysis extents that produced considerable bias or error in the estimate of NS. When is known or accurately estimated, and the assumptions of Wright’s neighborhood are met, the method we describe provides spatially explicit information regarding short-term genetic processes that may inform conservation genetic analyses and management
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