5,159 research outputs found
Procedures for graphical rectification of TIROS photographs
August 1965.Includes bibliographical references.Sponsored by U.S. Department of Commerce, Weather Bureau Cwb-10879
Propellant combustion phenomena during rapid depressurization Final report
Idealized combustion model in which exothermic or endothermic reactions are permitted at or very near solid-gas interface
Vertical momentum transport over mountainous terrain
Vertical momentum transport over mountainous terrain based on Apollo 9 cloud photographs, gravity waves, and wind data for southwestern U
Meteorological application of Apollo photography Final report
Development of meteorological information and parameters based on cloud photographs taken during Apollo 9 fligh
Vertical momentum transport over mountainous terrain
CER70-71GLW28.September, 1970.This report was prepared with support under contract number NAS 9-10305 National Aeronautics and Space Administration.High-resolution pictures obtained with a handheld camera during the earth-orbital photographic mission of the Apollo IX spacecraft provided a unique opportunity to map the areal extent of gravity waves over the southwestern United States. The orientation of cumulus streets and cirrus streaks augmented conventional wind data for momentum and kinetic energy calculations. Zonal shearing stress gradients in stably stratified air flowing over rugged mountainous terrain indicated very large subgrid-scale vertical fluxes of zonal momentum. Maximum stress values of several tens of dynes cm-2 occurred in the lower tropospheric layers where the air flow encountered the high Rocky Mountains of central New Mexico. The vertical fluxes of zonal momentum were directed upward to tropopause levels when extensive areas of gravity waves covered eastern Arizona, New Mexico, and western Texas. The potential energy contained in the wave population 5-2 attained values through the troposphere as high as 9.3 x 10 joules m 8-2 (9.3 x 10 ergs cm); this potential energy apparently played a substantial role in the energy budget. The residual "dissipation" term in the kinetic energy budget indicated a subgrid-scale flux of energy downward from the lower stratosphere concurrent with the upward flux of zonal momentum. Atmospheric turbulence rose to a maximum intensity during the wave occurrence, diminishing gradually thereafter.Under contract number NAS 9-10305
Rapid Evolution of the Fine-scale Recombination Landscape in Wild House Mouse (Mus musculus) Populations.
Meiotic recombination is an important evolutionary force and an essential meiotic process. In many species, recombination events concentrate into hotspots defined by the site-specific binding of PRMD9. Rapid evolution of Prdm9\u27s zinc finger DNA-binding array leads to remarkably abrupt shifts in the genomic distribution of hotspots between species, but the question of how Prdm9 allelic variation shapes the landscape of recombination between populations remains less well understood. Wild house mice (Mus musculus) harbor exceptional Prdm9 diversity, with \u3e150 alleles identified to date, and pose a particularly powerful system for addressing this open question. We employed a coalescent-based approach to construct broad- and fine-scale sex-averaged recombination maps from contemporary patterns of linkage disequilibrium in nine geographically isolated wild house mouse populations, including multiple populations from each of three subspecies. Comparing maps between wild mouse populations and subspecies reveals several themes. First, we report weak fine- and broad-scale recombination map conservation across subspecies and populations, with genetic divergence offering no clear prediction for recombination map divergence. Second, most hotspots are unique to one population, an outcome consistent with minimal sharing of Prdm9 alleles between surveyed populations. Finally, by contrasting aggregate hotspot activity on the X versus autosomes, we uncover evidence for population-specific differences in the degree and direction of sex dimorphism for recombination. Overall, our findings illuminate the variability of both the broad- and fine-scale recombination landscape in M. musculus and underscore the functional impact of Prdm9 allelic variation in wild mouse populations
PHYSICAL FACTORS REGULATING MACROBENTHIC COMMUNITY STRUCTURE ON A SOUTH AFRICAN ESTUARINE FLOOD-TIDAL DELTA
Multivariate techniques were used to identify environmental parameters affecting macrobenthic communities on the flood-tidal delta of the Nahoon Estuary and adjacent beach near East London on the south-east coast of South Africa. Water content of sediments, temperature and exposure were identified as important parameters regulating differences in community structure between high-shore and subtidal sites, and between beach sites of varying elevation. High organic content was important for similarity of communities at sites farthest from the mouth and for distinctness of these communities from the others. Sediment particle size, compactness and current velocity contributed to similar communities of channel sites and their variation from those of other sites, and to distinctness of the lowest beach site from higher beach sites. Sites in the mouth and in the middle of the flood-tidal delta, with similarities in community structure, had varying values for all the measured environmental variables and none of these parameters could explain why these sites had similar communities. In summary, no over-riding parameter was shown to dominate the abiotic driving forces at all sampling sites, and different variables were important for structuring communities at different sites.Afr. J. mar. Sci. 25: 263ā27
Cytokines That Serve as Embryokines in Cattle.
The term embryokine has been used to denote molecules produced by the endometrium, oviduct, or by embryo itself that will influence embryo development. Several cytokines have been identified as embryokines in cattle and other mammals. This review will describe how these cytokines function as embryokines, with special emphasis being placed on their actions on in vitro produced (IVP) bovine embryos. Embryokines are being explored for their ability to overcome the poor development rates of IVP embryos and to limit post-transfer pregnancy retention efficiencies that exist in IVP embryos. This review will focus on describing two of the best-characterized cytokines, colony-stimulating factor 2 and interleukin 6, for their ability to modify bovine embryo quality and confirmation, promote normal fetal development, and generate healthy calves. Additional cytokines will also be discussed for their potential to serve as embryokines
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