37,564 research outputs found

    Conformational studies of various hemoglobins by natural-abundance 13C NMR spectroscopy

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    Studies of variously liganded hemoglobins (both from human and rabbit) by natural-abundance 13C NMR spectroscopy have revealed apparent conformational differences that have been interpreted on the basis of two quaternary structures for the α2ß2 tetramer, and variable tertiary structures for the individual α and ß subunits. In solution, rabbit hemoglobins appear to have somewhat more flexibility than human hemoglobins

    Immune Suppression in Auto-Immune Hemolytic Anemia

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    The acquired auto-immune hemolytic anemias represent a diversity of disease states in which the most constant immunologic finding is a positive direct anti-human globulin test (van Loghem, 1965; Swisher et al, 1965). This is true of the symptomatic variety of acquired hemolytic anemia as well as the idiopathic form. The positive Coomb\u27s test has been seen in association with primary atypical pneumonias, occasionally in favism, in some bacterial and drug induced hemolytic anemias, in patients with malignancies of the lymphoid tissues, and in collagen-vascular disorders--chiefly SLE

    Consumer Willingness-to-Pay for Fresh Pork Attributes

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    A survey was used to gauge consumer preferences toward four fresh pork attributes: juiciness, tenderness, marbling, and leanness. The survey elicited consumer willingness-to-pay a premium for an improvement in these attributes. Approximately one-half of the respondents were willing to pay some premium for the attributes of juiciness, leanness, and tenderness. The average premium size ranged from 0.20/lb.formarblingto0.20/lb. for marbling to 0.37/lb. for tenderness. Neither the choice of a certifying agency nor the use of a cheap talk script influenced premium levels.pork attributes, pork markets, willingness to pay, Agribusiness, Marketing,

    Stable pseudoanalytical computation of electromagnetic fields from arbitrarily-oriented dipoles in cylindrically stratified media

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    Computation of electromagnetic fields due to point sources (Hertzian dipoles) in cylindrically stratified media is a classical problem for which analytical expressions of the associated tensor Green's function have been long known. However, under finite-precision arithmetic, direct numerical computations based on the application of such analytical (canonical) expressions invariably lead to underflow and overflow problems related to the poor scaling of the eigenfunctions (cylindrical Bessel and Hankel functions) for extreme arguments and/or high-order, as well as convergence problems related to the numerical integration over the spectral wavenumber and to the truncation of the infinite series over the azimuth mode number. These problems are exacerbated when a disparate range of values is to be considered for the layers' thicknesses and material properties (resistivities, permittivities, and permeabilities), the transverse and longitudinal distances between source and observation points, as well as the source frequency. To overcome these challenges in a systematic fashion, we introduce herein different sets of range-conditioned, modified cylindrical functions (in lieu of standard cylindrical eigenfunctions), each associated with non-overlapped subdomains of (numerical) evaluation to allow for stable computations under any range of physical parameters. In addition adaptively-chosen integration contours are employed in the complex spectral wavenumber plane to ensure convergent numerical integration in all cases. We illustrate the application of the algorithm to problems of geophysical interest involving layer resistivities ranging from 1000 Ω\Omega \cdotm to 108Ω^{-8} \Omega \cdotm, frequencies of operation ranging from 10 MHz down to the low magnetotelluric range of 0.01 Hz, and for various combinations of layer thicknesses.Comment: 33 pages, 23 figures. This v2 is slightly condensed and has some material moved to the Appendice

    Heat transfer in the tip region of a rotor blade simulator

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    In gas turbines, the blades of axial turbine stages rotate in close proximity to a stationary peripheral wall. Differential expansion of the turbine wheel, blades, and the shroud causes variations in the size of the clearance gap between blade tip and stationary shroud. The necessity to tolerate this differential thermal expansion dictates that the clearance gap cannot be eliminated altogether, despite accurate engine machining. Pressure differences between the pressure and suction sides of a blade drives a flow through the clearance gap. This flow, the tip leakage flow, is detrimental to engine performance. The primary detrimental effect of tip leakage flow is the reduction of turbine stage efficiency, and a second is the convective heat transfer associated with the flow. The surface area at the blade tip in contact with the hot working gas represents an additional thermal loading on the blade which, together with heat transfer to the suction and pressure side surface area, must be removed by the blade internal cooling flows. Experimental results concerned with the local heat transfer characteristics on all surfaces of shrouded, rectangular cavities are reported. A brief discussion of the mass transfer system used is given

    Contract Pricing and Packer Competition in Fed Cattle Market

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    We use a game-theoretical framework to analyze the coexistence of spot and contract markets in the cattle industry. A duopsony scenario with two packers and N feeders is used to reflect the reality in the cattle industry. Our main contribution is to incorporate the risk components and the pricing of hedonic attributes of cattle quality. Our preliminary results show that packers have an incentive to transform bidding strategies in spot markets when a series of hedonic characteristics play some significant roles in establishing cattle prices in contract market. That is, we will show that the effectiveness of contract with TOMP clauses on packer competition in a spot market depends on whether there is a correlation between spot price and hedonic characteristics. The results may shed light on understanding potential effects of captive supplies on market power and may aid in the assessment of the policies designed to enhance competition in the cattle industry.Marketing,
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