3,026 research outputs found

    Irrigation Development: It\u27s Potential Impact on South Dakota\u27s Economy

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    Irrigation development has been and will continue to be a key issue facing the people of the state of South Dakota. As irrigated acreage increases, benefits accrue throughout the State. The irrigator\u27s income earning potential is expanded and income variability is reduced as drought impacts on yields are ameliorated. In addition, a more stable, larger quantity of feed can be produced for livestock production. This may allm-1 for expansion in the livestock industry or less importation of feedstuffs into an area. The nonfarm economy may also benefit from irrigation development. Since irrigation requires the purchase of more inputs such as seed and fertilizer, allows for the feeding of more livestock and enhances consumption of nondurable and durable goods, what is the impact of develment on the State\u27s economy? It has been hypothesized and generally accepted that as irrigators increase purchases and sales, turnover or multiplier effects on the State\u27s economy are positive. The magnitude of these turnover effects on South Dakota\u27s economy, however, is not agreed upon

    Multiple effects of physical activity on molecular and cognitive signs of brain aging: can exercise slow neurodegeneration and delay Alzheimer\u27s disease?

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    Western countries are experiencing aging populations and increased longevity; thus, the incidence of dementia and Alzheimer\u27s disease (AD) in these countries is projected to soar. In the absence of a therapeutic drug, non-pharmacological preventative approaches are being investigated. One of these approaches is regular participation in physical activity or exercise. This paper reviews studies that have explored the relationship between physical activity and cognitive function, cognitive decline, AD/dementia risk and AD-associated biomarkers and processes. There is now strong evidence that links regular physical activity or exercise to higher cognitive function, decreased cognitive decline and reduced risk of AD or dementia. Nevertheless, these associations require further investigation, more specifically with interventional studies that include long follow-up periods. In particular, relatively little is known about the underlying mechanism(s) of the associations between physical activity and AD neuropathology; clearly this is an area in need of further research, particularly in human populations. Although benefits of physical activity or exercise are clearly recognised, there is a need to clarify how much physical activity provides the greatest benefit and also whether people of different genotypes require tailored exercise regimes.Molecular Psychiatry advance online publication, 20 November 2012; doi:10.1038/mp.2012.162

    Toward Greater Effectiveness in Community Change: Challenges and Responses for Philanthropy - Discussion Guide

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    The goal of this discussion guide is to assist foundations to engage in a dialogue about how philanthropy can become more effective in its support of community-change initiatives. The guide can be used in at least two ways. A foundation or a group of foundations intending to launch a community change initiative can use the guide as part of its planning process. Alternatively, foundations already involved in supporting a community-change initiative can use the guide as a framework to review the project's status and examine whether any changes in philanthropic practice make sense

    Toward Greater Effectiveness in Community Change: Challenges and Responses for Philanthropy - Executive Summary

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    Philanthropies of all types seek to improve communities—for lots of reasons, and in lots of different ways. Their efforts have produced promising results and some beginning lessons about community change. But more remains to be done to ensure that philanthropic investments in community change meet expectations and that funders use the emerging lessons to move their agendas forward. Based on interviews conducted for this paper, many funders are eager to take on that challenge

    High Specific Power Motors in LN2 and LH2

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    A switched reluctance motor has been operated in liquid nitrogen (LN2) with a power density as high as that reported for any motor or generator. The high performance stems from the low resistivity of Cu at LN2 temperature and from the geometry of the windings, the combination of which permits steady-state rms current density up to 7000 A/cm2, about 10 times that possible in coils cooled by natural convection at room temperature. The Joule heating in the coils is conducted to the end turns for rejection to the LN2 bath. Minimal heat rejection occurs in the motor slots, preserving that region for conductor. In the end turns, the conductor layers are spaced to form a heat-exchanger-like structure that permits nucleate boiling over a large surface area. Although tests were performed in LN2 for convenience, this motor was designed as a prototype for use with liquid hydrogen (LH2) as the coolant. End-cooled coils would perform even better in LH2 because of further increases in copper electrical and thermal conductivities. Thermal analyses comparing LN2 and LH2 cooling are presented verifying that end-cooled coils in LH2 could be either much longer or could operate at higher current density without thermal runaway than in LN2

    Exploring Factors Associated with Nonchange in Condom Use Behavior following Participation in an STI/HIV Prevention Intervention for African-American Adolescent Females

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    To enhance future STI/HIV prevention efforts, this study examined factors associated with adolescents' failure to improve their condom use behaviors after participating in an STI/HIV prevention intervention. African-American adolescent females (N = 205; M age = 17.9) in an STI/HIV prevention intervention trial completed ACASI interviews and provided self-collected vaginal swabs to assess two prevalent STIs at baseline and 6 months after intervention. Analyses compared those who increased condom use after intervention (change group) to those whose condom use did not increase (nonchange group). 43.4% did not increase their condom use after the intervention and were more likely to have an STI at followup (χ2 = 4.64, P = .03). In a multivariate logistic regression model, the nonchange group was more likely to have (a) higher sensation seeking (AOR = .91, P = .023), (b) a boyfriend (AOR = .32, P = .046), and/or (c) a physical abuse history (AOR = .56, P = .057). There were also differences in the extent to which psychosocial mediators changed between the two groups. Findings highlight the need to tailor STI/HIV interventions to adolescents with a greater degree of sensation seeking and address key relationship characteristics and trauma histories to bolster intervention efficacy

    Recent Decisions

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    Comments on recent decisions by Ralph H. Witt, Raymond Brown, Thomas A. McNish, Daniel J. Manelli, Stanley B. Nelson, George A. Pelletier, Jr., David T. Link, and Thomas Kavadas, Jr

    Altered patterns of gene duplication and differential gene gain and loss in fungal pathogens

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    <p>Abstract</p> <p>Background</p> <p>Duplication, followed by fixation or random loss of novel genes, contributes to genome evolution. Particular outcomes of duplication events are possibly associated with pathogenic life histories in fungi. To date, differential gene gain and loss have not been studied at genomic scales in fungal pathogens, despite this phenomenon's known importance in virulence in bacteria and viruses.</p> <p>Results</p> <p>To determine if patterns of gene duplication differed between pathogens and non-pathogens, we identified gene families across nine euascomycete and two basidiomycete species. Gene family size distributions were fit to power laws to compare gene duplication trends in pathogens <it>versus </it>non-pathogens. Fungal phytopathogens showed globally altered patterns of gene duplication, as indicated by differences in gene family size distribution. We also identified sixteen examples of gene family expansion and five instances of gene family contraction in pathogenic lineages. Expanded gene families included those predicted to be important in melanin biosynthesis, host cell wall degradation and transport functions. Contracted families included those encoding genes involved in toxin production, genes with oxidoreductase activity, as well as subunits of the vacuolar ATPase complex. Surveys of the functional distribution of gene duplicates indicated that pathogens show enrichment for gene duplicates associated with receptor and hydrolase activities, while euascomycete pathogens appeared to have not only these differences, but also significantly more duplicates associated with regulatory and carbohydrate binding functions.</p> <p>Conclusion</p> <p>Differences in the overall levels of gene duplication in phytopathogenic species <it>versus </it>non-pathogenic relatives implicate gene inventory flux as an important virulence-associated process in fungi. We hypothesize that the observed patterns of gene duplicate enrichment, gene family expansion and contraction reflect adaptation within pathogenic life histories. These adaptations were likely shaped by ancient, as well as contemporary, intimate associations with monocot hosts.</p

    Sprays formed by flashing liquid jets

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    Liquids forced from a high-pressure zone into a low-pressure zone often cross the equilibrium pressure for the liquid temperature and disintegrate into a spray by partial evolution of vapor. The ordinary aerosol dispenser is a common example of this operation, and flash boiling is another. This paper reports on a study of the sprays formed by such a process and of the mechanism of spray formation. Sprays from water and Freon-11 jets were analyzed for drop sizes, drop velocities, and spray patterns. The breakup mechanism was analyzed and data presented to show some of the controlling factors. A critical superheat was found, above which the jet of liquid is shattered by rapid bubble growth within it. The bubble-growth rate was correlated with the Weber number, and a critical value of the Weber number was found to be 12.5 for low-viscosity liquids. The mean drop size was also correlated with Weber number and degree of superheat. The spray from rough orifices and sharp-edged orifices was compared with sprays produced from cold liquids by other techniques and was found to be comparable in all respects except temperature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37323/1/690080204_ftp.pd
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