18,536 research outputs found

    Development of the elevation drive assembly for orbiting solar observatory I (EYE)

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    The requirements for pointing accuracy, friction, and power for the elevation drive assembly of an orbiting space observatory are discussed briefly. A description of the components making up the assembly is presented. Special features requiring development testing prior to unit fabrication are more fully described together with a review of the test programs conducted and results obtained

    Troposphere-stratosphere (surface-55 km) monthly general circulation statistics for the Northern Hemisphere-four year averages

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    This report presents four year averages of monthly mean Northern Hemisphere general circulation statistics for the period from 1 December 1978 through 30 November 1982. Computations start with daily maps of temperature for 18 pressure levels between 1000 and 0.4 mb that were supplied by NOAA/NMC. Geopotential height and geostrophic wind are constructed using the hydrostatic and geostrophic formulae. Fields presented in this report are zonally averaged temperature, mean zonal wind, and amplitude and phase of the planetary waves in geopotential height with zonal wavenumbers 1-3. The northward fluxes of heat and eastward momentum by the standing and transient eddies along with their wavenumber decomposition and Eliassen-Palm flux propagation vectors and divergences by the standing and transient eddies along with their wavenumber decomposition are also given. Large annual and interannual variations are found in each quantity especially in the stratosphere in accordance with the changes in the planetary wave activity. The results are shown both in graphic and tabular form

    Controlled Ecological Life Support Systems (CELSS) physiochemical waste management systems evaluation

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    Parametric data for six waste management subsystems considered for use on the Space Station are compared, i.e.: (1) dry incineration; (2) wet oxidation; (3) supercritical water oxidation; (4) vapor compression distillation; (5) thermoelectric integrated membrane evaporation system; and (6) vapor phase catalytic ammonia removal. The parameters selected for comparison are on-orbit weight and volume, resupply and return to Earth logistics, power consumption, and heat rejection. Trades studies are performed on subsystem parameters derived from the most recent literature. The Boeing Engineering Trade Study (BETS), an environmental control and life support system (ECLSS) trade study computer program developed by Boeing Aerospace Company, is used to properly size the subsystems under study. The six waste treatment subsystems modeled in this program are sized to process the wastes for a 90-day Space Station mission with an 8-person crew, and an emergency supply period of 28 days. The resulting subsystem parameters are compared not only on an individual subsystem level but also as part of an integrated ECLSS

    Mastitis in Dairy Cattle

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    Summary1. Mastitis is usually caused by a specific organism, Streptococus agalactiae.2. Mastitis occurs in one or more of the milking cows in nearly all herds of any size. It is more prevalent in old than in young cows.3. The most common symptoms of mastitis are: Swollen, in flamed quarters, flakes or lumps of curd in the milk and on the milk strainer pad.4. Mastitis producing bacteria enter the udder through the streak canal.5. There are several tests for detecting mastitis in milking cows. The microscopic inspection of milk in which the long chain streptococci organisms are found is the most dependable.6. Mastitis can be controlled by testing, observing sanitary practices in the barn, use of medicaments, and slaughter of the chronic cases that will not yield to treatment.The control and prevention of diseases and ailments in dairy herds mean more to the success of a well-bred dairy herd than any other single factor. As the herd increases in number and the individuals in the herd improve in production, diseases occur more frequently. This is only natural. With larger numbers more animals contact each other, increasing the possibilities of infection.High-producing animals are highly developed and therefore hard working. They cannot withstand the hardships and contagion of disease as can the boarder cow, which is largely on a maintenance basis

    A cell-permeable biscyclooctyne as a novel probe for the identification of protein sulfenic acids

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    Reactive oxygen species act as important second messengers in cell signaling and homeostasis through the oxidation of protein thiols. However, the dynamic nature of protein oxidation and the lack of sensitivity of existing molecular probes have hindered our understanding of such reactions; therefore, new tools are required to address these challenges. We designed a bifunctional variant of the strained bicyclo[6.1.0]nonyne (BCN-E-BCN) that enables the tagging of intracellular protein sulfenic acids for biorthogonal copper-free click chemistry. In validation studies, BCN-E-BCN binds the sulfenylated form of the actin-severing protein cofilin, while mutation of the cognate cysteine residues abrogates its binding. BCN-E-BCN is cell permeable and reacts rapidly with cysteine sulfenic acids in cultured cells. Using different azide-tagged conjugates, we demonstrate that BCN-E-BCN can be used in various applications for the detection of sulfenylated proteins. Remarkably, cycloaddition of an azide-tagged fluorophore to BCN-E-BCN labelled proteins produced in vivo can be visualized by fluorescence microscopy to reveal their subcellular localization. These findings demonstrate a novel and multifaceted approach to the detection and trapping of sulfenic acids

    A one-step procedure to probe the viscoelastic properties of cells by Atomic Force Microscopy

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    The increasingly recognised importance of viscoelastic properties of cells in pathological conditions requires rapid development of advanced cell microrheology technologies. Here, we present a novel Atomic Force Microscopy (AFM)-microrheology (AFM2) method for measuring the viscoelastic properties in living cells, over a wide range of continuous frequencies (0.005 Hz ~ 200 Hz), from a simple stress-relaxation nanoindentation. Experimental data were directly analysed without the need for pre-conceived viscoelastic models. We show the method had an excellent agreement with conventional oscillatory bulk-rheology measurements in gels, opening a new avenue for viscoelastic characterisation of soft matter using minute quantity of materials (or cells). Using this capability, we investigate the viscoelastic responses of cells in association with cancer cell invasive activity modulated by two important molecular regulators (i.e. mutation of the p53 gene and Rho kinase activity). The analysis of elastic (G′(ω)) and viscous (G″(ω)) moduli of living cells has led to the discovery of a characteristic transitions of the loss tangent (G″(ω)/G′(ω)) in the low frequency range (0.005 Hz ~ 0.1 Hz) that is indicative of the capability for cell restructuring of F-actin network. Our method is ready to be implemented in conventional AFMs, providing a simple yet powerful tool for measuring the viscoelastic properties of living cells

    An Analysis of Distributed Leadership Implementation In Schools

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    Many policymakers have sought greater levels of success in schools by implementing more distributive models of leadership, yet many have not achieved desired outcomes. This grounded theory study uncovers what happens within a school organization as it moves from a traditional leadership model to a district mandated distributive leadership model.https://scholarworks.waldenu.edu/archivedposters/1002/thumbnail.jp
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