2,762 research outputs found

    Systematic Development of Trans-Theoretically Based Behavioral Risk Management Programs

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    The authors explain the development and use of a behavioral Risk management strategy. It is designed for developing interventions to change behaviors, e.g., to lower the Risk of AIDS. The advantage of their strategy is said to be its structure combined with flexibility. Intervenors are not restricted to a single model in determining factors most relevant to changing Risky behavior

    Numerical Investigation Of Orographic Effects On Supercell Thunderstorms

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    Orographic effects on tornadic supercell development, propagation, and structure are investigated using the Cloud Model 1 with idealized bell-shaped mountains of various heights and geometries and a homogeneous fluid flow with a single sounding. In total, the variations of height and geometry yield 16 terrain configurations. It is found that blocking effects are dominative compared to the terrain-induced environmental heterogeneity downwind of the mountain. The isolated bell-shaped mountains tended to shift the track of the storm towards the left of storm motion; however, when the terrain was elongated the effect tended to be rightward. The terrain blocking effect also enhanced the supercells inflow. This allowed the central region of the storm to exhibit clouds with a greater density of hydrometeors than the NMTN control. Moreover, the enhanced inflow increased the areal extent of the supercells\u27 precipitation, which strengthened the cold pool and enhanced the storm\u27s updraft until becoming strong enough to undercut and weaken the storm considerably. Orographic blocking enhanced low-level vertical vorticity directly under the updraft when the storm approached the mountain. A modified NWS Tornado Detection Algorithm is used to investigate supercellular tornadogenesis; it is found that blocking effects are dominative and that elongating the terrain axis approximately parallel to the storm motion produces the strongest enhancement to tornadogenesis. Although the simulated cases with the highest mountains produced the most tornadic thunderstorms it is seen that increasing the terrain height alone is not sufficient to enhance tornadogenesis. Furthermore, an effective Froude number is developed to determine the amount of effective blocking that several terrain configurations exhibit in relation to both the mean winds and the storm relative winds, and although this effective Froude number does order the terrain geometries in an appropriate manner, it alone is not sufficient to concretely determine which orientation is most likely to enhance tornadogenesis in supercell thunderstorms

    Saturated fluorescence measurements of the hydroxyl radical in laminar high-pressure flames

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    The efficacy of laser saturated fluorescence (LSF) for OH concentration measurements in high pressure flames was studied theoretically and experimentally. Using a numerical model describing the interaction of hydroxyl with nonuniform laser excitation, the effect of pressure on the validity of the balanced cross-rate model was studied along with the sensitivity of the depopulation of the laser-coupled levels to the ratio of rate coefficients describing: (1) electronic quenching to (sup 2) Sigma (+) (v double prime greater than 0), and (2) vibrational relaxation from v double prime greater than 0 to v double prime = 0. At sufficiently high pressures and near-saturated conditions, the total population of the laser-coupled levels reaches an asymptotic value, which is insensitive to the degree of saturation. When the ratio of electronic quenching to vibrational relaxation is small and the rate of coefficients for rotational transfer in the ground and excited electronic states are nearly the same, the balanced cross-rate model remains a good approximation for all pressures. When the above ratio is large, depopulation of the laser-coupled levels becomes significant at high pressures, and thus the balanced cross-rate model no longer holds. Under these conditions, however, knowledge of the depletion of the laser-coupled levels can be used to correct the model. A combustion facility for operation up to 20 atm was developed to allow LSF measurements of OH in high pressure flames. Using this facility, partial saturation in laminar high pressure (less than or equal to 12.3 atm) C2H6/O2/N2 flames was achieved. To evaluate the limits of the balanced cross-rate model, absorption and calibrated LSF measurements at 3.1 and 6.1 atm were compared. The fluorescence voltages were calibrated with absorption measurements in an atmospheric flame and corrected for their finite sensitivity to quenching with: (1) estimated quenching rate coefficients, and (2) an in situ measurement from a technique employing two fluorescence detection geometries

    Suppressing Unwanted Autobiographical Memories Reduces Their Automatic Influences: Evidence from Electrophysiology and an Implicit Autobiographical Memory Test

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    The present study investigated the extent to which people can suppress unwanted autobiographical memories in a mock crime memory detection context. Participants encoded sensorimotor-rich memories by enacting a lab crime (stealing a ring) and received direct suppression instructions so as to evade guilt detection in a brainwave-based concealed information test. Aftereffects of suppression on automatic memory processes were measured in an autobiographical implicit association test (aIAT). Results showed that suppression attenuated brainwave activity (P300) that is associated with crime-relevant memory retrieval, rendering innocent and guilty/suppression participants indistinguishable. However, guilty/suppression and innocent participants could nevertheless be discriminated via the late posterior negative slow wave, which may reflect the need to monitor response conflict arising between voluntary suppression and automatic recognition processes. Lastly, extending recent findings that suppression can impair implicit memory processes; we provide novel evidence that suppression reduces automatic cognitive biases that are otherwise associated with actual autobiographical memories

    Addressing Problems in Evaluating Health-Relevant Programs through Systematic Planning and Evaluation

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    The authors argue that inconsistent terminology is often a hindrance in assessing health program implementation, effectiveness and efficiency. Attending closely to this, they propose a model scheme for conducting such evaluations

    Effect of Urea and Distillers Inclusion in Dry- Rolled Corn Based Diets on Heifer Performance and Carcass Characteristics

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    Crossbred heifers (n=96, BW = 810 ± 20) were utilized to evaluate the effects of increasing wet distillers grains plus solubles and urea inclusion in a dry rolled corn based finishing diet on performance and carcass characteristics. Heifers were individually fed using a calan gate system with a 2 × 2 factorial arrangement of treatments. Factors included distillers inclusion at either 10 or 20% of diet DM and urea inclusion at either 0.2 or 1.4% of diet DM. Th ere was no difference for final body weight, average daily gain, and feed conversion on a live or carcass adjusted basis for either urea or distillers inclusion in the diet. Dry matter intake was reduced with increased urea inclusion; however, distillers inclusion did not influence intake. Added distillers and urea in the diet had minimal impact on performance suggesting supplemental urea in a dry rolled corn based finishing diets is of minimal benefit when feeding at least 10% distillers grains

    Eelgrass in Estuarine Research Reserves Along the East Coast, USA

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    Eelgrass, Zostera marina L., is a submerged marine vascular plant that provides the basic structure of an extensive and important estuarine and coastal ecosystem. Currently, eelgrass populations around the world are declining dramatically due primarily to two causes: human pollution and a disease. The extensive loss of eelgrass threatens major alterations to the coastal environment and to the waterfowl and fish that depend on these plant communities. However, the eelgrass declines represent natural experiments that provide and opportunity to investigate a disease\u27s impact on an ecosystem, the characteristics of pollution-related declines, and finally, how declines from both causes can be diminished or mitigated
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