1,253 research outputs found

    Surface profilometer for examining grain-boundary grooves

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    Surface profilometer, consisting primarily of commercially available components, measures surface topographical features accurately and precisely. It shows improvement over the interferometric technique in measurement of grain-boundary grooves formed during annealing on nickel-oxide bicrystals

    X-ray polarimetry with an active-matrix pixel proportional counter

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    We report the first results from an X-ray polarimeter with a micropattern gas proportional counter using an amorphous silicon active matrix readout. With 100% polarized X-rays at 4.5 keV, we obtain a modulation factor of 0.33 +/- 0.03, confirming previous reports of the high polarization sensitivity of a finely segmented pixel proportional counter. The detector described here has a geometry suitable for the focal plane of an astronomical X-ray telescope. Amorphous silicon readout technology will enable additional extensions and improvements.Comment: 4 pages, 4 figures, 1 tabl

    MEASURING CONSUMER BENEFITS OF FOOD SAFETY RISK REDUCTIONS

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    Microbial pathogens and pesticide residues in food pose a financial burden to society which can be reduced by incurring costs to reduce these food safety risks. We explore three valuation techniques that place a monetary value on food safety risk reductions, and we present a case study for each: a contingent valuation survey on pesticide residues, an experimental auction market for a chicken sandwich with reduced risk of Salmonella, and a cost-of-illness analysis for seven foodborne pathogens. Estimates from these techniques can be used in cost/benefit analyses for policies that reduce food safety risks.Contingent valuation, Cost of illness, Experimental auction market, Food safety, Risk reduction, Salmonella, Food Consumption/Nutrition/Food Safety,

    Quality of Life measures for dementia

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    Over the past 10 years, several instruments developed specifically for the assessment of Quality of Life (QOL) in dementia have been introduced. The goal of the current review is to present, compare, and critique existing QOL measures for dementia populations to assist investigators and clinicians in selecting the optimal inventory for their specific needs. Nine measures are reviewed with a focus on conceptualizations of QOL, psychometric data, targeted patient population, and administration and scoring procedures. Critical discussion and comparison of the instruments is presented after the scales are described individually. Differences in definitions of QOL, assessment procedures, and methods that were used to establish the validity of instruments are highlighted. An important direction for future research on QOL scales for dementia is to establish their responsiveness to change over time. It will also be important to identify factors that affect reports of QOL, determine the how perceived QOL affects decisions regarding the care of dementia patients, and evaluate interventions to increase patient QOL

    Competing forces of withdrawal and disease avoidance in the risk networks of people who inject drugs

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    We analyze a network of needle-sharing ties among 117 people who inject drugs (PWID) in rural Puerto Rico, using exponential random graph modeling to examine whether network members engage in partner restriction to lower their risk of contracting HIV or hepatitis C (HCV), or in informed altruism to prevent others from contracting these infections. Although sharing of used syringes is a significant risk factor for transmission of these diseases among PWID, we find limited evidence for partner restriction or informed altruism in the network of reported needle-sharing ties. We find however that sharing of needles is strongly reciprocal, and individuals with higher injection frequency are more likely to have injected with a used needle. Drawing on our ethnographic work, we discuss how the network structures we observe may relate to a decision-making rationale focused on avoiding withdrawal sickness, which leads to risk-taking behaviors in this poor, rural context where economic considerations often lead PWID to cooperate in the acquisition and use of drugs

    Predicting the distribution of canine leishmaniasis in western Europe based on environmental variables.

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    The domestic dog is the reservoir host of Leishmania infantum, the causative agent of zoonotic visceral leishmaniasis endemic in Mediterranean Europe. Targeted control requires predictive risk maps of canine leishmaniasis (CanL), which are now explored. We databased 2187 published and unpublished surveys of CanL in southern Europe. A total of 947 western surveys met inclusion criteria for analysis, including serological identification of infection (504, 369 dogs tested 1971-2006). Seroprevalence was 23 2% overall (median 10%). Logistic regression models within a GIS framework identified the main environmental predictors of CanL seroprevalence in Portugal, Spain, France and Italy, or in France alone. A 10-fold cross-validation approach determined model capacity to predict point-values of seroprevalence and the correct seroprevalence class (20%). Both the four-country and France-only models performed reasonably well for predicting correctly the 20% seroprevalence classes (AUC >0 70). However, the France-only model performed much better for France than the four-country model. The four-country model adequately predicted regions of CanL emergence in northern Italy (<5% seroprevalence). Both models poorly predicted intermediate point seroprevalences (5-20%) within regional foci, because surveys were biased towards known rural foci and Mediterranean bioclimates. Our recommendations for standardizing surveys would permit higher-resolution risk mapping

    Notes on Recent Cases

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    Notes on recent cases by Marc Wonderlin, Francis T. Ready, Walter E. Parent, J. R. Harrington, James A. Allan, D. M. Donahue, J. J. Canty, J. S. Angelino, Henry Hasley, and John P. Berscheid
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