21,565 research outputs found

    Wider lessons of the pulmonary artery catheter trial.

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    An analytical method to predict efficiency of aircraft gearboxes

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    A spur gear efficiency prediction method previously developed by the authors was extended to include power loss of planetary gearsets. A friction coefficient model was developed for MIL-L-7808 oil based on disc machine data. This combined with the recent capability of predicting losses in spur gears of nonstandard proportions allows the calculation of power loss for complete aircraft gearboxes that utilize spur gears. The method was applied to the T56/501 turboprop gearbox and compared with measured test data. Bearing losses were calculated with large scale computer programs. Breakdowns of the gearbox losses point out areas for possible improvement

    Winter wheat: A model for the simulation of growth and yield in winter wheat

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    The basic ideas and constructs for a general physical/physiological process level winter wheat simulation model are documented. It is a materials balance model which calculates daily increments of photosynthate production and respiratory losses in the crop canopy. The partitioning of the resulting dry matter to the active growing tissues in the plant each day, transpiration and the uptake of nitrogen from the soil profile are simulated. It incorporates the RHIZOS model which simulates, in two dimensions, the movement of water, roots, and soluble nutrients through the soil profile. It records the time of initiation of each of the plant organs. These phenological events are calculated from temperature functions with delays resulting from physiological stress. Stress is defined mathematically as an imbalance in the metabolite supply; demand ratio. Physiological stress is also the basis for the calculation of rates of tiller and floret abortion. Thus, tillering and head differentiation are modeled as the resulants of the two processes, morphogenesis and abortion, which may be occurring simulaneously

    Covariance, correlation and entanglement

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    Some new identities for quantum variance and covariance involving commutators are presented, in which the density matrix and the operators are treated symmetrically. A measure of entanglement is proposed for bipartite systems, based on covariance. This works for two- and three-component systems but produces ambiguities for multicomponent systems of composite dimension. Its relationship to angular momentum dispersion for symmetric symmetric spin states is described.Comment: 30 pages, Latex, to appear in J Phys

    Black-holes, topological strings and large N phase transitions

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    The counting of microstates of BPS black-holes on local Calabi-Yau of the form O(p2)O(p)S2{\mathcal O}(p-2)\oplus{\mathcal O}(-p) \longrightarrow S^2 is explored by computing the partition function of q-deformed Yang-Mills theory on S2S^2. We obtain, at finite NN, the instanton expansion of the gauge theory. It can be written exactly as the partition function for U(N) Chern-Simons gauge theory on a Lens space, summed over all non-trivial vacua, plus a tower of non-perturbative instanton contributions. In the large NN limit we find a peculiar phase structure in the model. At weak string coupling the theory reduces to the trivial sector and the topological string partition function on the resolved conifold is reproduced in this regime. At a certain critical point, instantons are enhanced and the theory undergoes a phase transition into a strong coupling regime. The transition from the strong coupling phase to the weak coupling phase is of third order.Comment: 16 pages, 3 figures; Invited talk given at QG05, Cala Gonone (Italy), September 200

    Effects to Scalar Meson Decays of Strong Mixing between Low and High Mass Scalar Mesons

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    We analyze the mass spectroscopy of low and high mass scalar mesons and get the result that the coupling strengths of the mixing between low and high mass scalar mesons are very strong and the strengths of mixing for I=1,1/2I=1, 1/2 scalar mesons and those of I=0 scalar mesons are almost same. Next, we analyze the decay widths and decay ratios of these mesons and get the results that the coupling constants AA' for I=1,1/2I=1, 1/2 which represents the coupling of high mass scalar meson NN' -> two pseudoscalar mesons PPPP are almost same as the coupling AA' for the I=0. On the other hand, the coupling constant AA for I=1,I=1/2I=1, I=1/2 which represents the low mass scalar meson NN -> PPPP are far from the coupling constant AA for I=0. We consider a resolution for this discrepancy. Coupling constant AA'' for glueball GG -> PPPP is smaller than the coupling AA'. θP\theta_P is 405040^\circ \sim 50^\circ.Comment: 15 pages, 6 figure

    Mechanism for a next-to-lowest lying scalar meson nonet

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    Recent work suggests the existence of a non-conventional lowest-lying scalar nonet containing the a0(980). Then the a0(1450) and also the K0*(1430) are likely candidates to belong to a conventional p-wave qqˉq \bar q nonet. However a comparison of their properties with those expected on this basis reveals a number of puzzling features. It is pointed out that these puzzles can be resolved in a natural and robust way by assuming a ``bare'' conventional p-wave scalar qqˉq \bar q nonet to mix with a lighter four quark qqqˉqˉqq \bar q \bar q scalar nonet to form new ``physical'' states. The essential mechanism is driven by the fact that the isospinor is lighter than the isovector in the unmixed qqqˉqˉqq \bar q \bar q multiplet.Comment: 22 pages, 6 figure

    Sequence Analysis of HindIII Q2 Fragment of Capripoxvirus Reveals a Putative Gene Encoding a G-Protein-Coupled Chemokine Receptor Homologue

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    AbstractThe DNA sequence of the HindIII Q2 fragment near the left terminus of the capripoxvirus (KS-1 strain) genome was determined. The sequence contains two complete open reading frames (ORFs) and a part of a third. Analysis of the deduced amino acid sequence of one of these ORFs, Q2/3L, revealed that this gene has the capacity to encode a protein which is related to members of the G-protein coupled chemokine receptor subfamily, the swinepoxvirus K2R and the human cytomegalovirus US28 ORFs. It has the key structural characteristics of the G-protein-coupled receptor superfamily, e.g., seven hydrophobic regions, predicted to span the cell membrane, and the cysteine residues in the first and second extracellular loops that are implicated in formation of a disulfide bond. Southern blot analysis showed that all three species of the Capripoxvirus genus, i.e., sheep pox, goat pox, and lumpy skin disease of cattle, contain copies of this putative G-proteincoupled chemokine receptor homologue
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