1,971 research outputs found

    Instability of the Ekman Spiral with Applications to the Planetary Boundary Layers

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    Spiral boundary layer instability applied to planetary boundary layer

    LANDSAT menhaden and thread herring resources investigation

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    The author has identified the following significant results. The most significant achievement is the successful charting of high probability fishing areas from LANDSAT MSS data

    LANDSAT follow-on experiment: Gulf of Mexico menhaden and thread herring resources investigation

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    The author has identified the following significant results. The most significant achievement realized is the successful mapping of high probability fishing areas from LANDSAT MSS data for two Mississippi Sound missions

    Multicanonical Parallel Tempering

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    We present a novel implementation of the parallel tempering Monte Carlo method in a multicanonical ensemble. Multicanonical weights are derived by a self-consistent iterative process using a Boltzmann inversion of global energy histograms. This procedure gives rise to a much broader overlap of thermodynamic-property histograms; fewer replicas are necessary in parallel tempering simulations, and the acceptance of trial swap moves can be made arbitrarily high. We demonstrate the usefulness of the method in the context of a grand-multicanonical ensemble, where we use multicanonical simulations in energy space with the addition of an unmodified chemical potential term in particle-number space. Several possible implementations are discussed, and the best choice is presented in the context of the liquid-gas phase transition of the Lennard-Jones fluid. A substantial decrease in the necessary number of replicas can be achieved through the proposed method, thereby providing a higher efficiency and the possibility of parallelization.Comment: 8 pages, 3 figure, accepted by J Chem Phy

    LANDSAT menhaden and thread herring resources investigation, Gulf of Mexico

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    The author has identified the following significant results. The most significant achievements thus far include the successful charting of high probability fishing areas from LANDSAT MSS data and the successful simulation of an operational satellite system to provide tactical information for the commercial harvest of menhaden

    FEASIBILITY OF A SHEEP COOPERATIVE FOR GRAZING LEAFY SPURGE

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    This report presents an economic feasibility study of a 5,000 head, cooperatively owned, sheep operation for leafy spurge control. The objectives were 1) determine the return on investment of the cooperative, 2) determine the proposed structure of the cooperative, and 3) ascertain the amount of capital investment required by members in the cooperative. Three sheep flock management alternatives were initially considered for the cooperative. These were 1) winter lambing, 2) spring lambing, and 3) fall lambing. The fall lambing scenario was determined to be infeasible because of logistics associated with gathering and transportation of pregnant ewes and lack of grazing pressure on leafy spurge throughout the grazing season. The total capital investment per ewe for the winter lambing scenario was more than the spring lambing scenario - - 301and301 and 216, respectively. The expected net income generated by the winter lambing scenario was negative. The minimum break-even lamb selling price or lambs sold per ewe for the winter lambing scenario was 84.10/cwtand1.33,respectively.Thespringlambingscenarioreturned84.10/cwt and 1.33, respectively. The spring lambing scenario returned 124,000 annually. The minimum breakeven lamb selling price or lambs sold per ewe for the spring lambing scenario was $59.51/cwt and 0.94, respectively. The expected return on investment (50% equity) for cooperative members with the spring lambing scenario, assuming a 50-acre leafy spurge infestation in a 100-acre pasture and new fence, was 16 percent (stocking rate of 1 ewe and lambs per acre of leafy spurge). While these returns are not a guarantee of success for the spring lambing alternative, they do provide an indication of the potential that such a cooperative may have.Leafy Spurge, Cooperative, Weed Control, Sheep Grazing, Economics, Farm Management, Resource /Energy Economics and Policy, Agribusiness,

    LANDSAT menhaden and thread herring resources investigation

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    The author has identified the following significant results. The relationship between the distribution of menhaden and selected oceanographic parameters (water color, turbidity, and possibly chlorophyll concentrations) was established. Similar relationships for thread herring were not established nor were relationships relating to the abundance of either species. Use of aircraft and LANDSAT remote sensing instruments to measure or infer a set of basic oceanographic parameters was evaluated. Parameters which could be accurately inferred included surface water temperature, salinity, and color. Water turbidity (Secchi disk) was evaluated as marginally inferrable from the LANDSAT MSS data and chlorophyll-a concentrations as less than marginal. These evaluations considered the parameters only as experienced in the two test areas using available sensors and statistical techniques

    Optical interferometer in space

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    The present design concepts for a Laser Gravitational Wave Observatory in Space are described. Laser heterodyne distance measurements are made between test masses located in three spacecraft separated by roughly 10(exp 6) km. The major technology issues are: the reduction of spurious acceleration noise for the test masses to below 2 x 10(exp -15) cm/sq sec/Hz(0.5) from 10(exp -5) to 10(exp -3) Hz; and the measurement of changes in the difference of the antenna arm lengths to 5 x 10(exp -11) cm/Hz(0.5) from 10(exp -3) to 1 Hz with high reliability. The science objectives are: to measure discrete sinusoidal gravitational wave signals from individual sources with periods of 1 second to 1 day; to measure the stochastic background due to unresolved binaries; and to search for gravitational wave pulses with periods longer than 1 sec from possible exotic sources such as gravitational collapse of very massive objects

    Ribose supplementation alone or with elevated creatine does not preserve high energy nucleotides or cardiac function in the failing mouse heart

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    Background: Reduced levels of creatine and total adenine nucleotides (sum of ATP, ADP and AMP) are hallmarks of chronic heart failure and restoring these pools is predicted to be beneficial by maintaining the diseased heart in a more favourable energy state. Ribose supplementation is thought to support both salvage and re-synthesis of adenine nucleotides by bypassing the rate-limiting step. We therefore tested whether ribose would be beneficial in chronic heart failure in control mice and in mice with elevated myocardial creatine due to overexpression of the creatine transporter (CrT-OE). Methods and Results: Four groups were studied: sham; myocardial infarction (MI); MI+ribose; MI+CrT-OE+ribose. In a pilot study, ribose given in drinking water was bioavailable, resulting in a two-fold increase in myocardial ribose-5-phosphate levels. However, 8 weeks post-surgery, total adenine nucleotide (TAN) pool was decreased to a similar amount (8–14%) in all infarcted groups irrespective of the treatment received. All infarcted groups also presented with a similar and substantial degree of left ventricular (LV) dysfunction (3-fold reduction in ejection fraction) and LV hypertrophy (32–47% increased mass). Ejection fraction closely correlated with infarct size independently of treatment (r2 = 0.63, p<0.0001), but did not correlate with myocardial creatine or TAN levels. Conclusion: Elevating myocardial ribose and creatine levels failed to maintain TAN pool or improve post-infarction LV remodeling and function. This suggests that ribose is not rate-limiting for purine nucleotide biosynthesis in the chronically failing mouse heart and that alternative strategies to preserve TAN pool should be investigated

    A PRELIMINARY FEASIBILITY FOR ESTABLISHING A MULTI-SPECIES MEAT PROCESSING PLANT IN SOUTHWESTERN NORTH DAKOTA

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    The number of small commodity livestock slaughter plants in the Upper Northern Plains region continues to decline. Significant factors contributing to this decline include: 1) pressure to consolidate, thereby capturing economies of scale; 2) relatively stringent federal inspection specifications, along with; 3) HACCP (Hazardous Analysis Critical Control Points) requirements. At the same time, consumer demand (markets) for specialty, selected, and exotic meats appears to be growing. For example, the recent market successes in Europe evidenced by the North American Bison Cooperative based in New Rockford, North Dakota. Several alternative livestock producer groups have emerged which include lamb, ratite, elk, deer, goat, poultry, rabbit, specialty beef, and organic livestock. These groups have expressed a need for slaughter and processing facilities to meet market demand. The economic question which then becomes foremost to developing a viable business enterprise is: "What is the critical threshold volume (CTV) of product required to succeed in terms of economic profit?" Specialty livestock is relatively new and production volume small in comparison to established commodity livestock such as cattle or hogs. This fact led researchers to consider the preliminary feasibility of a multi-species processing facility as a means of addressing the expressed need.multi-species, specialty meats, specialty livestock, alternative livestock, economies of scale, HACCP (Hazardous Analysis Critical Control Points), slaughter plants, processing plants, Community/Rural/Urban Development, Agribusiness,
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