3,380 research outputs found

    The political economy of quality measurement: a case study of the USA slaughter cattle market

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    As agricultural products move from being economic commodities to qualitydifferentiated goods, price dispersion within specific markets increases and implicit subsidies from high quality producers to low quality producers are removed. The present paper examines how these distributional effects can influence patterns of support and opposition to changes in marketing arrangements. The simple model developed is calibrated using data from the USA slaughter cattle market. Estimates of the impact on prices of measuring quality more accurately are found to be similar in size to previous estimates of market power price suppression in the market.Livestock Production/Industries,

    On Technology Neutral Policies for E–identity: a Critical Reflection Based on UK Identity Policy

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    This paper reviews the arguments for technology neutral e–identity policies. It uses the recent experience of identity policy in the UK, as well as a consideration of technological developments, to distinguish between two perspectives on technology neutral policies: legal and technological. Whilst the legal perspective on technology neutrality is intended to provide legal certainty, it fails to address discontinuous technological developments such as zero–knowledge systems and risk based assessments of identity and attribute claims. These are transforming the basis of identity policies and highlight the challenges of proposing technology neutral identity policies in law. The paper then applies the technological critique of technology neutrality to review a recent study on identity, authentication and signature policy in the EU

    Understanding Algorithm Performance on an Oversubscribed Scheduling Application

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    The best performing algorithms for a particular oversubscribed scheduling application, Air Force Satellite Control Network (AFSCN) scheduling, appear to have little in common. Yet, through careful experimentation and modeling of performance in real problem instances, we can relate characteristics of the best algorithms to characteristics of the application. In particular, we find that plateaus dominate the search spaces (thus favoring algorithms that make larger changes to solutions) and that some randomization in exploration is critical to good performance (due to the lack of gradient information on the plateaus). Based on our explanations of algorithm performance, we develop a new algorithm that combines characteristics of the best performers; the new algorithms performance is better than the previous best. We show how hypothesis driven experimentation and search modeling can both explain algorithm performance and motivate the design of a new algorithm

    Across the Mississippi

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    Improved sampling of the pareto-front in multiobjective genetic optimizations by steady-state evolution: a Pareto converging genetic algorithm

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    Previous work on multiobjective genetic algorithms has been focused on preventing genetic drift and the issue of convergence has been given little attention. In this paper, we present a simple steady-state strategy, Pareto Converging Genetic Algorithm (PCGA), which naturally samples the solution space and ensures population advancement towards the Pareto-front. PCGA eliminates the need for sharing/niching and thus minimizes heuristically chosen parameters and procedures. A systematic approach based on histograms of rank is introduced for assessing convergence to the Pareto-front, which, by definition, is unknown in most real search problems. We argue that there is always a certain inheritance of genetic material belonging to a population, and there is unlikely to be any significant gain beyond some point; a stopping criterion where terminating the computation is suggested. For further encouraging diversity and competition, a nonmigrating island model may optionally be used; this approach is particularly suited to many difficult (real-world) problems, which have a tendency to get stuck at (unknown) local minima. Results on three benchmark problems are presented and compared with those of earlier approaches. PCGA is found to produce diverse sampling of the Pareto-front without niching and with significantly less computational effort

    Associations of height, leg length, and lung function with cardiovascular risk factors in the Midspan Family Study

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    <b>Background</b>: Taller people and those with better lung function are at reduced risk of coronary heart disease (CHD). Biological mechanisms for these associations are not well understood, but both measures may be markers for early life exposures. Some studies have shown that leg length, an indicator of pre-pubertal nutritional status, is the component of height most strongly associated with CHD risk. Other studies show that height-CHD associations are greatly attenuated when lung function is controlled for. This study examines (1) the association of height and the components of height (leg length and trunk length) with CHD risk factors and (2) the relative strength of the association of height and forced expiratory volume in one second (FEV1) with risk factors for CHD. <b>Subjects and methods</b>: Cross sectional analysis of data collected at detailed cardiovascular screening examinations of 1040 men and 1298 women aged 30–59 whose parents were screened in 1972–76. Subjects come from 1477 families and are members of the Midspan Family Study. <b>Setting</b>: The towns of Renfrew and Paisley in the West of Scotland. <b>Results</b>: Taller subjects and those with better lung function had more favourable cardiovascular risk factor profiles, associations were strongest in relation to FEV1. Higher FEV1 was associated with lower blood pressure, cholesterol, glucose, fibrinogen, white blood cell count, and body mass index. Similar, but generally weaker, associations were seen with height. These associations were not attenuated in models controlling for parental height. Longer leg length, but not trunk length, was associated with lower systolic and diastolic blood pressure. Longer leg length was also associated with more favourable levels of cholesterol and body mass index than trunk length. <b>Conclusions</b>:These findings provide indirect evidence that measures of lung development and pre-pubertal growth act as biomarkers for childhood exposures that may modify an individual's risk of developing CHD. Genetic influences do not seem to underlie height-CHD associations

    Determination of Fluoride by Precipitation of Lead Chlorofluoride: Comparison of Classical and Homogeneous Precipitation Methods

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    Optimal conditions for the homogeneous precipitation of lead chlorofluoride were investigated and the method was compared with the classical procedure. The most suitable reagent for the pH control of the homogeneous solution was found to be urea \\u27.ith ammonium acetate buffer. If the precipitate obtained by both procedures was allowed to stand overnight, homogeneous precipitation resulted with more accurate data

    An Anatomy of European Information Systems Research ECIS 1993 - 2002: Some Initial Findings

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    This paper reflects on European research on information systems as presented during the first ten years of the European Conference on Information Systems (ECIS). Based on an analysis of all papers published in the ECIS proceedings during the period 1993–2002, the paper presents initial findings regarding key aspects of European IS research activity

    Bullying in Graduate School: Its Nature and Effects

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    Does bullying exist in graduate school? If so, what does it look like? Semi-structured interviews were conducted with 22 graduate students from various departments at a medium-sized, Midwestern U.S. university. Grounded Theory methodology (Glaser, 1978) was utilized to gain insight into the terms and behaviors students used to define bullying in the graduate school context. Through constant comparative analysis (Stern, 1980), categories emerged that provided an understanding of the different perspectives inherent in a bully system, and the meanings attached to bullying behaviors. These findings can provide administrators and counselors with the information necessary to conduct preventative training to help students interact in a more professional, inclusive manner
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