54,168 research outputs found

    Rate constant for deuterium atom recombination calculated by the orbiting resonance theory

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    Resonance theory for three body recombination kinetics for calculating recombination rate constant of deuterium ato

    Wide range operation of advanced low NOx combustors for supersonic high-altitude aircraft gas turbines

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    An initial rig program tested the Jet Induced Circulation (JIC) and Vortex Air Blast (VAB) systems in small can combustor configurations for NOx emissions at a simulated high altitude, supersonic cruise condition. The VAB combustor demonstrated the capability of meeting the NOx goal of 1.0 g NO2/kg fuel at the cruise condition. In addition, the program served to demonstrate the limited low-emissions range available from the lean, premixed combustor. A follow-on effort was concerned with the problem of operating these lean, premixed combustors with acceptable emissions at simulated engine idle conditions. Various techniques have been demonstrated that allow satisfactory operation on both the JIC and VAB combustors at idle with CO emissions below 20 g/kg fuel. The VAB combustor was limited by flashback/autoignition phenomena at the cruise conditions to a pressure of 8 atmospheres. The JIC combustor was operated up to the full design cruise pressure of 14 atmospheres without encountering an autoignition limitation although the NOx levels, in the 2-3 g NO2/kg fuel range, exceeded the program goal

    Yeast gene CMR1/YDL156W is consistently co-expressed with genes participating in DNA-metabolic processes in a variety of stringent clustering experiments

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    © 2013 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0/, which permits unrestricted use, provided the original author and source are credited.The binarization of consensus partition matrices (Bi-CoPaM) method has, among its unique features, the ability to perform ensemble clustering over the same set of genes from multiple microarray datasets by using various clustering methods in order to generate tunable tight clusters. Therefore, we have used the Bi-CoPaM method to the most synchronized 500 cell-cycle-regulated yeast genes from different microarray datasets to produce four tight, specific and exclusive clusters of co-expressed genes. We found 19 genes formed the tightest of the four clusters and this included the gene CMR1/YDL156W, which was an uncharacterized gene at the time of our investigations. Two very recent proteomic and biochemical studies have independently revealed many facets of CMR1 protein, although the precise functions of the protein remain to be elucidated. Our computational results complement these biological results and add more evidence to their recent findings of CMR1 as potentially participating in many of the DNA-metabolism processes such as replication, repair and transcription. Interestingly, our results demonstrate the close co-expressions of CMR1 and the replication protein A (RPA), the cohesion complex and the DNA polymerases α, δ and ɛ, as well as suggest functional relationships between CMR1 and the respective proteins. In addition, the analysis provides further substantial evidence that the expression of the CMR1 gene could be regulated by the MBF complex. In summary, the application of a novel analytic technique in large biological datasets has provided supporting evidence for a gene of previously unknown function, further hypotheses to test, and a more general demonstration of the value of sophisticated methods to explore new large datasets now so readily generated in biological experiments.National Institute for Health Researc

    Advanced Low NO Sub X Combustors for Supersonic High-Altitude Aircraft Gas Turbines

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    A test rig program was conducted with the objective of evaluating and minimizing the exhaust emissions, in particular NO sub x, of three advanced aircraft combustor concepts at a simulated, high altitude cruise condition. The three combustor designs, all members of the lean reaction, premixed family, are the Jet Induced Circulation (JIC) combustor, the Vortex Air Blast (VAB) combustor, and a catalytic combustor. They were rig tested in the form of reverse flow can combustors in the 0.127 m. (5.0 in.) size range. Various configuration modifications were applied to each of the initial JIC and VAB combustor model designs in an effort to reduce the emissions levels. The VAB combustor demonstrated a NO sub x level of 1.1 gm NO2/kg fuel with essentially 100% combustion efficiency at the simulated cruise combustor condition of 50.7 N/sq cm (5 atm), 833 K (1500 R) inlet pressure and temperature respectively and 1778 K (3200 R) outlet temperature on Jet-A1 fuel. Early tests on the catalytic combustor were unsuccessful due to a catalyst deposition problem and were discontinued in favor of the JIC and VAB tests. In addition emissions data were obtained on the JIC and VAB combustors at low combustor inlet pressure and temperatures that indicate the potential performance at engine off-design conditions

    The Value of Regional Annual Nitrogen Needs Information for Wheat Producers in Oklahoma

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    Crop producers are increasingly interested in reducing nitrogen use without sacrificing yield. Technology is available for precise application at the sub-field level, but adoption has been sluggish. This paper estimates the relative profitability of a field level annual predictor of mid-season N requirements and a regional predictor of the same.nitrogen seeds, nitrogen use efficiency, precision agriculture, wheat, Crop Production/Industries, Research and Development/Tech Change/Emerging Technologies,

    Hot Electron Capture Dissociation Distinguishes Leucine from Isoleucine in a Novel Hemoglobin Variant, Hb Askew, β54(D5)Val→Ile

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    Population migration has led to the global dispersion of human hemoglobinopathies and has precipitated a need for their identification. An effective mass spectrometry-based procedure involves analysis of the intact α- and β-globin chains to determine their mass, followed by location of the variant amino acid residue by direct analysis of the enzymatically digested chains and low-energy collision induced dissociation of the variant peptide. Using this procedure, a variant was identified as either β54Val→Leu or β54Val→Ile, since the amino acids leucine and isoleucine cannot be distinguished using low-energy collisions. Here, we describe how hot electron capture dissociation on a Fourier transform-ion cyclotron resonance mass spectrometer was used to distinguish isoleucine from leucine and identify the mutation as β54(D5)Val→Ile. This is a novel variant, and we have named it Hb Askew

    The importance of habitat quality for marine reserve fishery linkages

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    We model marine reserve - fishery linkages to evaluate the potential contribution of habitat-quality improvements inside a marine reserve to fish productivity and fishery catches. Data from Mombasa Marine National Park, Kenya, and the adjacent fishery are used. Marine reserves increase total fish biomass directly by providing refuge from exploitation and indirectly by improving fish habitat in the reserve. As natural mortality of the fish stock decreases in response to habitat enhancement in the reserve, catches increase by up to 2.6 tonnes (t).km(-2).year(-1) and total fish biomass by up to 36 t.km(-2). However, if habitat-quality improvement reduces the propensity of fish to move out of the reserve, catches may fall by up to 0.9 t.km(-2).year(-1). Our results indicate that habitat protection in reserves can underpin fish productivity and, depending on its effects on fish movements, augment catches

    Pseudovector components of the pion, pi^0 -> gamma gamma, and F_pi(q^2)

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    As a consequence of dynamical chiral symmetry breaking the pion Bethe-Salpeter amplitude necessarily contains terms proportional to gamma_5 gamma.P and gamma_5 gamma.k, where k is the relative and P the total momentum of the constituents. These terms are essential for the preservation of low energy theorems, such as the Gell-Mann--Oakes-Renner relation and those describing anomalous decays of the pion, and to obtaining an electromagnetic pion form factor that falls as 1/q^2 for large q^2, up to calculable ln(q^2)-corrections. In a simple model, which correlates low- and high-energy pion observables, we find q^2 F_pi(q^2) ~ 0.12 - 0.19 GeV^2 for q^2 >~10 GeV^2.Comment: 15 pages, 2 figures, REVTE

    Replicability of nitrogen recommendations from ramped calibration strips in winter wheat

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    Ramped calibration strips have been suggested as a way for grain producers to determine nitrogen needs more accurately. The strips use incrementally increasing levels of nitrogen and enable producers to conduct an experiment in each field to determine nitrogen needs. This study determines whether predictions from the program Ramp Analyzer 1.2 are replicable in Oklahoma hard red winter wheat (Triticum aestivum). Predictions are derived from 36 individual strips from on-farm experiments—two pairs of adjacent strips at each of nine winter wheat fields in Canadian County, OK. The two pairs of strips within each field were between 120 and 155 m apart. Each strip was analyzed three times during the 2006–2007 growing season. Nitrogen recommendations from Ramp Analyzer 1.2 are not correlated even for strips that were placed side by side, and recommendations from strips in the same field show no more homogeneity than randomly selected strips throughout the county. The results indicate that ramped calibration strips are unlikely to produce accurate nitrogen requirement predictions at any spatial scale, whether at the county level or for subsections of a single field. In contrast, a procedure that uses only measures from the plot with no nitrogen and the plot with the highest level of nitrogen applied does show replicability. Thus, improvements in the ramped calibration strip technology are needed if it is to become viable.Fertilizer; Nitrogen; Precision agriculture; Ramped calibration strip; Winter wheat
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