18,938 research outputs found

    Explorations of Respectability and Resistance in Constructions of Black Womanhood at HBCUs

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    Somewhere in her college experience she must have an opportunity to develop poise, to increase her self-esteem and to establish a sense of her worth and dignity as an individual. She must experience peace and beauty in her environment and she must be accorded the respect and courtesy, which is so lacking in her life on the outside. The education of the Negro woman should give her an opportunity to exhaust to the fullest her powers of expression and creativit

    Farming Systems in the Central West of NSW: An Economic Analysis

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    The objectives of this report have been to describe important farming systems in the Central West of NSW, to gain some insights into current financial performance and to examine in more detail the role of pastures in these farming systems at a time when the profitability of wool growing has been low relative to grain growing. While farms and farming systems vary considerably across the region, a majority can be broadly grouped into a mixed livestock and cropping category. Although there is also significant variability within this category, two representative farms and farming systems were developed for the region with the assistance from a small group of farmers and extension staff from NSW Agriculture. One represents the farms and farming systems east of Condobolin and the other represents the farms and farming systems to the west of Condobolin. Whole-farm budget models have been developed for each to provide a description of the farms in this region and an indication of their current profitability. They are useful to give an indication of how farm income might be altered by the introduction of some new technology, a new enterprise such a pulse crop, or an alternative management practice. This report presents some examples of their application but importantly it has provided a template for the development of additional whole-farm budgets for alternative farming systems in this and other regions. Using the whole-farm budget representing farms east of Condobolin, and a linear programming model, PRISM Condobolin, this report shows that the optimal length of pasture is fairly insensitive to changing market signals for both cropping and livestock commodities. It also shows that although length of pasture is insensitive, the optimal mix of enterprises does change, highlighting the importance of considering the interactions between enterprises in whole-farm analysis.Industrial Organization, Production Economics,

    Pre-Heated Isentropic Gas in Groups of Galaxies

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    We confirm that the standard assumption of isothermal, shock-heated gas in cluster potentials is unable to reproduce the observed X-ray luminosity- temperature relation of groups of galaxies. As an alternative, we construct a physically motivated model for the adiabatic collapse of pre-heated gas into an isothermal potential that improves upon the original work of Kaiser (1991). The luminosity and temperature of the gas is calculated, assuming an appropriate distribution of halo formation times and radiation due to both bremsstrahlung and recombination processes. This model successfully reproduces the slope and dispersion of the luminosity-temperature relation of galaxy groups. We also present calculations of the temperature and luminosity functions for galaxy groups under the prescription of this model. This model makes two strong predictions for haloes with total masses M<10^13 M_sun, which are not yet testable with current data: (1) the gas mass fraction will increase in direct proportion to the halo mass; (2) the gas temperature will be larger than the virial temperature of the mass. The second effect is strong enough that group masses determined from gas temperatures will be overestimated by about an order of magnitude if it is assumed that the gas temperature is the virial temperature. The entropy required to match observations can be obtained by heating the gas at the turnaround time, for example, to about 3 X 10^6 K at z=1, which is too high to be generated by a normal rate of supernova explosions. This model breaks down on the scale of low mass clusters, but this is an acceptable limitation, as we expect accretion shocks to contribute significantly to the entropy of the gas in such objects.Comment: Final, refereed version, accepted by MNRAS. One new figure and several clarifying statements have been added. Uses mn.a4.sty (hacked mn.sty). Also available from http://astrowww.phys.uvic.ca/~balogh/entropy.ps.g

    Analogic Thinking in Science and Math

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    Ocean services user needs assessment. Volume 1: Survey results, conclusions and recommendations

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    An interpretation of environmental information needs of marine users, derived from a direct contact survey of eight important sectors of the marine user community is presented. Findings of the survey and results and recommendations are reported. The findings consist of specific and quantized measurement and derived product needs for each sector and comparisons of these needs with current and planned NOAA data and services. The following supportive and reference material are examined: direct contact interviews with industry members, analyses of current NOAA data gathering and derived product capabilities, evaluations of new and emerging domestic and foreign satellite data gathering capabilities, and a special commercial fishing survey conducted by the Jet Propulsion Laboratory (JPL)

    Synthesis of perfluorinated polyethers

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    A series of highly fluorinated acetylenes was prepared and their cyclization reactions were studied. A series of perfluoropolytriazines with -CF2I pendent groups were prepared. These materials can be cured thermally or photochemically to an elastomeric gum. Perfluoropolytriazines with -CN pendent groups were prepared. These materials can be crosslinked by reaction with terephthalonitrile oxide
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