25,586 research outputs found

    Experimental study and evaluation of radioprotective drugs

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    Experimental study evaluates radioprotective drugs administered before exposure either orally or intravenously. Specifically studied are the sources of radiation, choice of radiation dose, choice of animals, administration of drugs, the toxicity of protective agents and types of protective drug

    Recent advancements in information extraction methodology and hardware for Earth Resources Survey Systems

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    There are no author-identified significant results in this report

    Sensitivity-analysis method for inverse simulation application

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    An important criticism of traditional methods of inverse simulation that are based on the Newton–Raphson algorithm is that they suffer from numerical problems. In this paper these problems are discussed and a new method based on sensitivity-analysis theory is developed and evaluated. The Jacobian matrix may be calculated by solving a sensitivity equation and this has advantages over the approximation methods that are usually applied when the derivatives of output variables with respect to inputs cannot be found analytically. The methodology also overcomes problems of input-output redundancy that arise in the traditional approaches to inverse simulation. The sensitivity- analysis approach makes full use of information within the time interval over which key quantities are compared, such as the difference between calculated values and the given ideal maneuver after each integration step. Applications to nonlinear HS125 aircraft and Lynx helicopter models show that, for this sensitivity-analysis method, more stable and accurate results are obtained than from use of the traditional Newton–Raphson approach

    Regional Unemployment Disparities.

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    In this paper we examine the nature of disparities in regional (State) unemployment rates in Australia over the period 1978-1999 and their relationship to the national unemployment rate. As a measure of dispersion we use the sum of the (weighted) deviations of regional unemployment rates from the national rate. We show that this figure may be interpreted as the number of new jobs or labour force movements that would be needed to even out unemployment rates between regions, expressed as a proportion of the total number currently employed in all regions. Using co-integration analysis, we find that there is a (long-run) relationship between the degree of dispersion in the regional unemployment rates and the level of the national unemployment rate. The relationship between the two is negative implying that, as the national unemployment rate falls, micro and/or differentiated labour markets policies need to bite harder (and affect proportionately more people) if equity in unemployment across regions is to be maintained. We also find that the trade-off between dispersion and unemployment has become steeper in the period following significant deregulation of the Australian economy in the early Nineteen-Eighties. It would appear likely that this reflects an increase in differences in the Natural Rate of Unemployment between the regions since that time.UNEMPLOYMENT ; REGIONAL DEVELOPMENT

    Knowledge of Objective 'Oughts': Monotonicity and the New Miners Puzzle

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    In the classic Miners case, an agent subjectively ought to do what they know is objectively wrong. This case shows that the subjective and objective ‘oughts’ are somewhat independent. But there remains a powerful intuition that the guidance of objective ‘oughts’ is more authoritative—so long as we know what they tell us. We argue that this intuition must be given up in light of a monotonicity principle, which undercuts the rationale for saying that objective ‘oughts’ are an authoritative guide for agents and advisors

    Multispectral scanner data applications evaluation. Volume 1: User applications study

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    A six-month systems study of earth resource surveys from satellites was conducted and is reported. SKYLAB S-192 multispectral scanner (MSS) data were used as a baseline to aid in evaluating the characteristics of future systems using satellite MSS sensors. The study took the viewpoint that overall system (sensor and processing) characteristics and parameter values should be determined largely by user requirements for automatic information extraction performance in quasi-operational earth resources surveys, the other major factor being hardware limitations imposed by state-of-the-art technology and cost. The objective was to use actual aircraft and spacecraft MSS data to outline parametrically the trade-offs between user performance requirements and hardware performance and limitations so as to allow subsequent evaluation of compromises which must be made in deciding what system(s) to build

    NASA/FAA general aviation crash dynamics program

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    The program involves controlled full scale crash testing, nonlinear structural analyses to predict large deflection elastoplastic response, and load attenuating concepts for use in improved seat and subfloor structure. Both analytical and experimental methods are used to develop expertise in these areas. Analyses include simplified procedures for estimating energy dissipating capabilities and comprehensive computerized procedures for predicting airframe response. These analyses are developed to provide designers with methods for predicting accelerations, loads, and displacements on collapsing structure. Tests on typical full scale aircraft and on full and subscale structural components are performed to verify the analyses and to demonstrate load attenuating concepts. A special apparatus was built to test emergency locator transmitters when attached to representative aircraft structure. The apparatus is shown to provide a good simulation of the longitudinal crash pulse observed in full scale aircraft crash tests

    Mode-selective toroidal mirrors for unstable resonator planar waveguide and thin slab solid-state lasers

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    Comparative Studies on Gonad Development in the Rat, the Pig and in Cattle

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    The relatively clear and simple developmental pattern of the frog gonad (Witschi 1914, 1924, 1929) makes it a good basic type with which to compare the sex glands of higher vertebrates. The origin and development of the elements of the sex glands of higher vertebrates, especially mammals, are not as clear as in amphibia
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