96,266 research outputs found

    Studies on the denaturation of antibody: II. The effect of protein concentration on the rate of denaturation of diphtheria antitoxin by urea

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    The specific rate of inactivation of antitoxin in urea solutions, as measured by the Römer neutralization test with toxin, has been shown to be independent of the concentration of protein under the conditions studied. The amount of precipitate obtained in the quantitative precipitation test with toxin, however, increases greatly with increasing protein concentration during denaturation. The time during which the protein concentration is important in this respect has been shown to be the interval in which the urea is being dialyzed from the solutions. The meaning of the results is discussed

    Studies on the denaturation of antibody. IV. The influence of pH and certain other factors on the rate of inactivation of Staphylococcus antitoxin in urea solutions

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    In previous work on the denaturation of antibody, studies have been made of some of the factors influencing the inactivation of diphtheria antitoxin in urea solutions (1, 2). A quantitative formulation of a simple kinetic theory was found to fit satisfactorily the experimental data and to offer a reasonable explanation of the deviation of the inactivation from simple first order behavior (2). In the present work we have studied the inactivation of Staphylococcus antitoxin, investigating the influence of certain new factors on the rate and course of the over-all reaction, with a view toward gaining further insight into the mechanism of the reactions, and reinvestigating the influence of pH, a factor studied previously with diphtheria antitoxin, in order to test the applicability of the proposed kinetic mechanism to different antibodies

    The 20/30 GHz satellite systems technology needs assessment

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    Rain attenuation in the 20/30 GHz bands, and the resultant impact on system user costs were estimated for a variety of satellite communication system concepts. Results of previous and current NASA Lewis contractual and in-house studies on system design are reported as well as market studies conducted to evaluate the concepts and test their relevancy against forecasted market needs. The 20/30 GHz bands appear attractive economically and, with certain technology, appear to offer a virtually unlimited spectrum resource. This attractiveness is especially relevant to high density trunking where there is sufficient traffic to justify dual-station site diversity

    Large-scale computation of pseudospectra using ARPACK and eigs

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    ARPACK and its MATLAB counterpart, eigs, are software packages that calculate some eigenvalues of a large non-symmetric matrix by Arnoldi iteration with implicit restarts. We show that at a small additional cost, which diminishes relatively as the matrix dimension increases, good estimates of pseudospectra in addition to eigenvalues can be obtained as a by-product. Thus in large-scale eigenvalue calculations it is feasible to obtain routinely not just eigenvalue approximations, but also information as to whether or not the eigenvalues are likely to be physically significant. Examples are presented for matrices with dimension up to 200,000

    Voltage regulator with plural parallel power source sections Patent

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    Dissipative voltage regulator system for minimizing heat dissipatio

    On galaxy rotation curves from a continuum mechanics approach to modified gravity

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    We consider a modification of General Relativity motivated by the treatment of anisotropies in Continuum Mechanics. The Newtonian limit of the theory is formulated and applied to galactic rotation curves. By assuming that the additional structure of spacetime behaves like a Newtonian gravitational potential for small deviations from isotropy, we are able to recover the Navarro-Frenk-White profile of dark matter halos by a suitable identification of constants. We consider the Burkert profile in the context of our model and also discuss rotation curves more generally.Comment: 8 pages; v2 11 pages, heavily revised version, new title; v3 13 pages final versio

    Execution: the Critical “What’s Next?” in Strategic Human Resource Management

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    The Human Resource Planning Society’s 1999 State of the Art/Practice (SOTA/P) study was conducted by a virtual team of researchers who interviewed and surveyed 232 human resource and line executives, consultants, and academics worldwide. Looking three to five years ahead, the study probed four basic topics: (1) major emerging trends in external environments, (2) essential organizational capabilities, (3) critical people issues, and (4) the evolving role of the human resource function. This article briefly reports some of the study’s major findings, along with an implied action agenda – the “gotta do’s for the leading edge. Cutting through the complexity, the general tone is one of urgency emanating from the intersection of several underlying themes: the increasing fierceness of competition, the rapid and unrelenting pace of change, the imperatives of marketplace and thus organizational agility, and the corresponding need to buck prevailing trends by attracting and, especially, retaining and capturing the commitment of world-class talent. While it all adds up to a golden opportunity for human resource functions, there is a clear need to get to get on with it – to get better, faster, and smarter – or run the risk of being left in the proverbial dust. Execute or be executed
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