2,009 research outputs found

    Tropospheric monitoring technology for gravity wave experiments

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    Tropospheric refractivity fluctuations are an important error source for gravity wave detection by Doppler tracking in that they alter the phase and phase rate of electromagnetic signals. Estimates are presented of the effect of tropospheric fluctuations on the Doppler signal and some examples are suggested of methods which minimize the effect. A model of the fluctuations is utilized to achieve those goals. Four possible methods for reducing the fluctuation effect are suggested: (1) observation and analysis strategies, which separate the atmospheric and gravity wave signatures; (2) water vapor radiometry for the wet component; (3) calibration using Global Positioning System (GPS) satellites; and (4) Doppler observations from multiple antennas to average fluctuation effects. The last two techniques could be used to calibrate both wet and dry fluctuations, or could be used in conjunction with water vapor radiometry to calibrate only the dry component

    5KW pulse width modulated static inverter

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    Design verification tests for logic and low level circuits, and preliminary single-phase breadboard of pulse width modulated static inverte

    Strength and Stiffness of Preservative-Treated Marine Piles

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    An assessment was made of the effect of preservative treatments on bending strength and stiffness of full-sized marine piles and small specimens derived from them and on the compression strength of pile sections. Preservative-treated Southern pine and Douglas-fir piles were generally lower in strength than untreated piles. Dual treatments of ACA plus creosote and CCA plus creosote reduced strength more than single treatments with these preservatives. Stiffness and strength in compression were not affected by preservative treatment. Statistical associations between MOE and MOR values of small specimens and full-sized piles in bending were extremely small

    J Fluorescence

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    The scope of this paper is to illustrate the need for an improved quality assurance in fluorometry. For this purpose, instrumental sources of error and their influences on the reliability and comparability of fluorescence data are highlighted for frequently used photoluminescence techniques ranging from conventional macro- and microfluorometry over fluorescence microscopy and flow cytometry to microarray technology as well as in vivo fluorescence imaging. Particularly, the need for and requirements on fluorescence standards for the characterization and performance validation of fluorescence instruments, to enhance the comparability of fluorescence data, and to enable quantitative fluorescence analysis are discussed. Special emphasis is dedicated to spectral fluorescence standards and fluorescence intensity standards

    Serotonin mediated changes in corticotropin releasing factor mRNA expression and feeding behavior isolated to the hypothalamic paraventricular nuclei

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    Fenfluramine reduces hunger and promotes body weight loss by increasing central serotonin (5-HT) signaling. More recently, neuropeptides have been linked to the regulation of feeding behavior, metabolism and body weight. To examine possible interactions between 5-HT and neuropeptides in appetite control, fenfluramine (200 nmol/0.5 μl/side) was administered directly into the hypothalamic paraventricular nuclei (PVN) of male rats. Bilateral fenfluramine produced significant hypophagia and increased expression of PVN corticotropin releasing factor (CRF) mRNA and neuropeptide Y (NPY) mRNA in the arcuate nucleus within the first hour after drug administration. Fenfluramine\u27s effects on feeding behavior and mRNA expression were blocked by PVN injections of a 5-HT1–2 receptor antagonist, metergoline (15 nmol/0.5 μl/side). These data suggest that 5-HT neurons targeting hypothalamic paraventricular CRF neurons may participate in an appetite control circuit for reducing food intake

    Optimization study of high power static inverters and converters Final report

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    Optimization study and basic performance characteristics for conceptual designs for high power static inverter
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