1,691 research outputs found

    Responses of White-Footed Mice and Meadow Voles to Flyovers of an Aerial Predator Silhouette

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    Author Institution: Department of Zoology, The Ohio State University; Department of Poultry and Wildlife Sciences, University of NebraskaThe response of white-footed mice and meadow voles to a stylized hawk model pulled overhead was studied. Behavior such as looking up and following the path of the model, immobility, and/or entering a nest can was observed and statistically analyzed. Overall responsiveness peaked as the model passed directly overhead. Stationary models elicited fewer instances of immobility than moving models while significantly increasing the number of white-footed mice that entered nest cans. Meadow voles were more likely to move about the 36 x 20 x 15 cm cage, but not into nest cans, during stop-go flyovers than during non-stop flyovers

    Energy Siting in Utah: A Programming Model

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    Using a conceptual model of a multiple-product firm, the necessary conditions for an optimal input and output allocation were determined for a region constrained by resource availabilities and/or policy constraints. A linear programming model was developed to deteremine the optimal allocation of water between agricultural and coal-fired electrical generating entities as well as the trade offs which could occur if electrical generation were increased. Other areas of potential trade offs such as coal source restrictions and air quality regualtions were also examined. Coal mining and transportation costs were included as were SO2, Nox, and particulate emission rates on a coal and plant basis. Few trade offs between electrical power generation and irrigated agriculture were noted. However, substantial changes within the energy sector were discovered as coal capacities and air quality energy sector were discovered as coal capacities and air quality standards were changed. Net revenues declined sharply as air costs after and/or pollution and coal capacity restrictions were imposed and/or increased. It was determined that substantial changes in regional economic activity occurred as a result of these restrictions on development

    Thermodynamic and Kinetic Aspects of Two- and Three-Electron Redox Processes Mediated by Nitrogen Atom Transfer

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    Treatment of (meso-tetra-p-tolylporphyrinato)manganese(V) nitride, (TTP)Mn==N, with (octaethylporphyrinato) manganese(II), Mn(OEP), in toluene leads to the reversible transfer of the nitrido ligand between the two metal complexes to form (OEP)Mn Nand Mn(TTP). The net result is a formal three-electron reduction of (TTP)MnvN to (TTP)Mn11• This occurs with a second-order rate constant of (5.6 ± 1.2) X 103 M-1 s-1 to form an equilibrium mixture with K~ = 1.2 ± 0.5 at 20 °C. The thermodynamic and activation parameters for this process are t:.H0 = 2.0 ± 0.2 kcalfmol, t:.S = 7 .I ± 0.6 calfmol·K, t:.H* = 9.4 ± 0.7 kcal/mol, and t:.S* = -10 ± 2 cal/mol·K. In THF at 20 °C, the equilibrium constant is 1.8 ± 0.2 and the rate constant drops to 2.3 ± 0.3 M-1 s-1• When a manganese(III) porphyrin complex is used as a reductant, reversible nitrogen atom transfer still occurs but mediates a formal two-electron process. At 22 °C, the exchange process between (TTP)MnCI and (OEP)Mn==N produces (TTP)Mn==N and (OEP)MnCI with a second-order rate constant of 0.010 ± 0.007 M-1 s-1 (t:.H* = 19 ± 2 kcal/mol and t:.S* = -3 ± 6 cal/mol·K) and forms an equilibrium mixture with Keq = 24.3 ± 3.3 (t:.H 0 = -7.0 ± 0.6 kcal/mol and t:.S 0 = -17 ± 2 cal/mol·K). Evidence for the formation of a binuclear wnitrido intermediate is presented for both processes. For the two-electron redox reaction, kinetic studies and mechanistic probes support a pathway which involves an initial chloride dissociation from the Mn(III) complex. Nitrogen atom transfer subsequently occurs between the Mn==N complex and the four-coordinate Mn(III) cationic species

    Performance of Sweetpotato for Bioregenerative Life Support

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    Sweetpotato was successfully grown to harvest maturity in a large-scale atmospherically-closed controlled environment chamber. Yield of edible biomass and capacity for contributing to air revitalization and water recovery were documented. Yield was slightly less than that found in smaller-scale studies, but this is not unusual (Wheeler 1999). Continued work is suggested to improve control of storage root initiation, bulking and vine growth

    Evaluation of a potato leafhopper (PLH) resistant alfalfa cultivar effects on PLH injury in alfalfa: grass mixed stands with and without insecticide.

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    The combination of a resistant cultivar and a grass resulted in significantly better PLH control than did the resistant cultivar alone or the grass alone. The resistant cultivar had 36% fewer PLH than the susceptible cultivar; however, the number of PLH was significantly higher than for the plots that were sprayed with insecticide (average less than 1 PLH per sub-plot). The untreated plot with the lowest PLH damage score was the resistant alfalfa/grass mixture (score = 1.8), whereas the resistant cultivar alone scored 2.4 and the susceptible cultivar alone and with grass averaged 3.5

    A Chance-Constrained Programming Model of Water Allocations in Utah

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    A chance-constrained separable programming model of water allocations between agriculture and energy production was developed in order to examine the effect of the variability of water supplies in Utah. Using an incomplete gamma function, based on method of moments estimation of parameters, the water flows at 85, 90, and 95 percent probabilities of occurence were generated. These flows were then used as constraints in the allocation model. Results indicate that water quality could be a more significant constraint on irrigated agriculture than water quantity in the face of large scale energy development, and the variability of water availability alone is likely not to be a significant factor in economic growth in Utah

    Augmentation of Staphylococcal α-Toxin Signaling by the Epidermal Platelet-Activating Factor Receptor

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    Staphylococcal α-toxin is a cytolytic toxin secreted by many strains of Staphylococcus aureus that has proinflammatory and cytotoxic effects on human keratinocytes. α-toxin exerts its effects by forming a transmembrane pore that behaves like an ionophore for ions such as calcium. Because cellular membrane disruption with resultant intracellular calcium mobilization is a potent stimulus for the synthesis for the lipid mediator platelet-activating factor, the ability of α-toxin to induce platelet-activating factor production was assessed, and whether the epidermal platelet-activating factor receptor could augment toxin-induced signaling in epithelial cells examined. Treatment of the human keratinocyte-derived cell line HaCaT with α-toxin resulted in significant levels of platelet-activating factor, which were approximately 50% of the levels induced by calcium ionophore A23187. α-toxin also stimulated arachidonic acid release in HaCaT keratinocytes. Pretreatment of HaCaT cells with platelet-activating factor receptor antagonists, or overexpression of the platelet-activating factor metabolizing enzyme acetylhydrolase II blunted α-toxin-induced arachidonic acid release by approximately one-third, suggesting a role for toxin-produced platelet-activating factor in this process. Finally, retroviral-mediated expression of the platelet-activating factor receptor into the platelet-activating factor receptor-negative epithelial cell line KB resulted in an augmentation of α-toxin-mediated intracellular calcium mobilization and arachidonic acid release. These studies suggest that α-toxin-mediated signaling can be augmented via the epidermal platelet-activating factor receptor

    Wheat hay for livestock

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    The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311
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