24,697 research outputs found

    Orbiting multi-beam microwave radiometer for soil moisture remote sensing

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    The effects of soil moisture and other factors on soil surface emissivity are reviewed and design concepts for a multibeam microwave radiometer with a 15 m antenna are described. Characteristic antenna gain and radiation patterns are shown and losses due to reflector roughness are estimated

    Flutter Clearance of the F-14A Variable-Sweep Transition Flight Experiment Airplane, Phase 2

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    An F-14A aircraft was modified for use as the test-bed aircraft for the variable-sweep transition flight experiment (VSTFE) program. The VSTFE program was a laminar flow research program designed to measure the effects of wing sweep on laminar flow. The airplane was modified by adding an upper surface foam and fiberglass glove to the right wing. An existing left wing glove had been added for the previous phase of the program. Ground vibration and flight flutter testing were accomplished to verify the absence of aeroelastic instabilities within a flight envelope of Mach 0.9 or 450 knots, calibrated airspeed, whichever was less. Flight test data indicated satisfactory damping levels and trends for the elastic structural modes of the airplane. Ground vibration test data are presented along with in-flight frequency and damping estimates, time histories and power spectral densities of in-flight sensors, and pressure distribution data

    Building capacity for evidence-based public health: Reconciling the pulls of practice and the push of research

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    Timely implementation of principles of evidence-based public health (EBPH) is critical for bridging the gap between discovery of new knowledge and its application. Public health organizations need sufficient capacity (the availability of resources, structures, and workforce to plan, deliver, and evaluate the preventive dose of an evidence-based intervention) to move science to practice. We review principles of EBPH, the importance of capacity building to advance evidence-based approaches, promising approaches for capacity building, and future areas for research and practice. Although there is general agreement among practitioners and scientists on the importance of EBPH, there is less clarity on the definition of evidence, how to find it, and how, when, and where to use it. Capacity for EBPH is needed among both individuals and organizations. Capacity can be strengthened via training, use of tools, technical assistance, assessment and feedback, peer networking, and incentives. Modest investments in EBPH capacity building will foster more effective public health practice

    Neglected Dimensions of Global Security: The Global Health Risk Framework Commission

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    The world has experienced global health crises ranging from novel influenzas (H5N1 and H1N1) and coronaviruses (SARS and MERS) to the Ebola and Zika viruses. In each case, governments and international organizations seemed unable to react quickly and decisively. Health crises have unmasked critical vulnerabilities— weak health systems, failures of leadership, and political overreaction and underreaction. The Global Health Risk Framework Commission, for which the National Academy of Medicine served as the secretariat, recently set out a comprehensive strategy to safeguard human and economic security from pandemic threats

    Estimates of galactic cosmic ray shielding requirements during solar minimum

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    Estimates of radiation risk from galactic cosmic rays are presented for manned interplanetary missions. The calculations use the Naval Research Laboratory cosmic ray spectrum model as input into the Langley Research Center galactic cosmic ray transport code. This transport code, which transports both heavy ions and nucleons, can be used with any number of layers of target material, consisting of up to five different arbitrary constituents per layer. Calculated galactic cosmic ray fluxes, dose and dose equivalents behind various thicknesses of aluminum, water and liquid hydrogen shielding are presented for the solar minimum period. Estimates of risk to the skin and the blood-forming organs (BFO) are made using 0-cm and 5-cm depth dose/dose equivalent values, respectively, for water. These results indicate that at least 3.5 g/sq cm (3.5 cm) of water, or 6.5 g/sq cm (2.4 cm) of aluminum, or 1.0 g/sq cm (14 cm) of liquid hydrogen shielding is required to reduce the annual exposure below the currently recommended BFO limit of 0.5 Sv. Because of large uncertainties in fragmentation parameters and the input cosmic ray spectrum, these exposure estimates may be uncertain by as much as a factor of 2 or more. The effects of these potential exposure uncertainties or shield thickness requirements are analyzed

    Analysis of airborne imaging spectrometer data for the Ruby Mountains, Montana, by use of absorption-band-depth images

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    Airborne Imaging Spectrometer-1 (AIS-1) data were obtained for an area of amphibolite grade metamorphic rocks that have moderate rangeland vegetation cover. Although rock exposures are sparse and patchy at this site, soils are visible through the vegetation and typically comprise 20 to 30 percent of the surface area. Channel averaged low band depth images for diagnostic soil rock absorption bands. Sets of three such images were combined to produce color composite band depth images. This relative simple approach did not require extensive calibration efforts and was effective for discerning a number of spectrally distinctive rocks and soils, including soils having high talc concentrations. The results show that the high spectral and spatial resolution of AIS-1 and future sensors hold considerable promise for mapping mineral variations in soil, even in moderately vegetated areas

    Radiation exposure for manned Mars surface missions

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    The Langley cosmic ray transport code and the Langley nucleon transport code (BRYNTRN) are used to quantify the transport and attenuation of galactic cosmic rays (GCR) and solar proton flares through the Martian atmosphere. Surface doses are estimated using both a low density and a high density carbon dioxide model of the atmosphere which, in the vertical direction, provides a total of 16 g/sq cm and 22 g/sq cm of protection, respectively. At the Mars surface during the solar minimum cycle, a blood-forming organ (BFO) dose equivalent of 10.5 to 12 rem/yr due to galactic cosmic ray transport and attenuation is calculated. Estimates of the BFO dose equivalents which would have been incurred from the three large solar flare events of August 1972, November 1960, and February 1956 are also calculated at the surface. Results indicate surface BFO dose equivalents of approximately 2 to 5, 5 to 7, and 8 to 10 rem per event, respectively. Doses are also estimated at altitudes up to 12 km above the Martian surface where the atmosphere will provide less total protection

    The Effect of Recombinant Bovine Somatotropin on Patterns of Milk Production, Lactational Milk Estimates and Net Farm Income

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    Bovine somatoropin (bST) alters total milk production and production patterns in dairy cows and understanding the economic benefits of bST for the dairy producer are critical. Holstein cows (n = 555) from four Michigan dairy farms were randomly assigned as untreated controls or to receive 500 mg of bovine somatotropin (PosilacR) administered every 14 days beginning at 63 to 69 days of lactation and continuing until approximately 21 days prior to the end of lactation or until the animal was removed from the herd. Average peak milk production was 50.8 kg / day and occurred at an average of 113 9 days of lactation for bST-treated cows while average peak production was 48.9 kg / day occurring at an average of 86.4 days of lactation for control cows; both parameters were significantly greater for bST-treated cows compared to controls. Study cows treated with bST were significantly more persistent in lactation (7% greater lactational persistency) compared to control cows. All DHIA estimates and actual milk produced were not significantly different between the study treatment groups for any of the four comparisons made (first, second, third monthly tests after bST treatment initiation and final (305-day) DHIA production estimates); however, the accuracy of DHIA production estimates was significantly affect by the amount of time elapsed since bST but became non-significant by the third DHIA test date. The use of bST changed NFI for each of the four study farms by 96.21,96.21, 3.57, 78.71and(78.71 and (7.15) per bST-treated cow, respectively during the trial period (from 63 to 305 days of lactation). The overall average change in NFI attributable to bST was $43.01 per bST-treated cow. 2 Profitability of bST use was observed to be quite variable between farms studied because many factors were found to affect the change in NFI per cow resulting from bST use; the level of production response and the price received for milk had the largest effects on the change in NFI associated with bST use; by contrast, price paid for bST itself and feed had only minimal effects on bST-associated profitability. Diseases that may be associated with bST may reduce the profitability of this product and need to be considered as a cost of bST use if present.bovine somatotropin, dairy, net farm income, Farm Management, Livestock Production/Industries, Productivity Analysis, Research and Development/Tech Change/Emerging,

    Modeling Equilibrium of microRNA Expression

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    MicroRNAs are a class of non-coding RNAs and the dysregulated expression of these short RNA molecules was frequently observed in cancer cells. The steady state level of microRNA concentration may differentiate the biological function of the cells between normal and impaired. To understand the steady state or equilibrium of microRNAs, their interactions with transcription factors and target genes need to be explored and visualized through prediction and network analysis algorithms. This article discusses the application of mathematical model for simulating the dynamics of network feedback loop so as to decipher the mechanism of microRNA regulation
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