3,756 research outputs found

    Machines Versus Humans: The Counting and Recounting of Pre-Scored Punchcard Ballots

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    The counting of ballots, especially punchcard ballots, has received a great deal of attention in the years following the 2000 presidential election in Florida. Much of the research literature has focused on various measures of how accurately voting machines record voter intentions, with studies of the relative accuracy rates across voting machines (e.g., Caltech/MIT Voting Technology Project 2001), studies of voting accuracy across groups of the electorate (Alvarez and Sinclair 2003), and studies that examine the variability in voting machine accuracy across both machine types and voter types (Alvarez, Sinclair and Wilson 2002; Ansolabehere 2002; Tomz and Van Houweling 2003).Carnegie Corporation of New York; John S. and James L. Knight Foundation; John Randolph Haynes and Dora Haynes Foundatio

    Re-analysis of ammonia spectra: Updating the HITRAN 14NH3 database

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    AbstractThe data incorporated in the HITRAN database for 14NH3 are analyzed using a comprehensive and consistent set of quantum numbers, empirical lower energy levels and the BYTe variationally calculated line list as reference points. Labelings are checked to ensure that they obey both the usual selection rules and the HITRAN labeling formalisms; the problems identified are corrected where possible. Further assignments are brought into question by combination difference (CD) checking of implied upper energy levels. The CD analysis yields an 89% complete 14NH3 energy level list up to 6610cm−1 and J=21, self-consistent to 0.1cm−1. In combination with the 1723 previously unassigned and unlabeled lines in HITRAN a total of 2529 problem lines were identified for re-analysis. The compiled energy level list was used to label and assign the set of problem transitions, resulting in a total of 249 new assignments and a further 368 new labelings. Assignment by comparison with the reference line list resulted in 111 further new line assignments and 14 new labelings. Intensities are checked against recent measurements and BYTe. New intensities are proposed for the ν2 band with new intensities and line positions for the 2ν2−ν2 and new line lists are created for the ν2−ν2, ν2−ν4 and ν4−ν4 bands. BYTe band intensities are analyzed to identify other regions of missing intensity

    Mediators of Treatment Effect in the Back In Action Trial:Using Latent Growth Modeling to Take Change Over Time Into Account

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    Objectives: To test whether change in fear-avoidance beliefs was a mediator of the effect of treatment on disability outcome, and to test an analytical approach, latent growth modeling, not often applied to mediation analysis. Methods: Secondary analysis was carried out on a randomized controlled trial designed to compare an intervention addressing fear-avoidance beliefs (n=119) with treatment as usual (n=121) for patients with low back pain, which found the intervention to be effective. Latent growth modelling was used to perform a mediation analysis on the trial data to assess the role of change in fear-avoidance beliefs on disability outcome. The product of coefficients with bias-corrected bootstrapped confidence intervals was used to calculate the mediating effect. Results: A statistically significant mediating effect of fear-avoidance beliefs on the effect of treatment on disability outcome was found (standardized indirect effect −0.35; bias-corrected 95% CI, −0.47 to −0.24). Poor fit of the model to the data suggested that other factors not accounted for in this model are likely to be part of the same mediating pathway. Discussion: Fear-avoidance beliefs were found to mediate the effect of treatment on disability outcome. Measurement of all potential mediator variables in future studies would help to more strongly identify which factors explain observed treatment effects. Latent growth modelling was found to be a useful technique to apply to studies of treatment mediation, suggesting that future studies could use this approach

    A comparative study of WASP-67b and HAT-P-38b from WFC3 data

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    Atmospheric temperature and planetary gravity are thought to be the main parameters affecting cloud formation in giant exoplanet atmospheres. Recent attempts to understand cloud formation have explored wide regions of the equilibrium temperature-gravity parameter space. In this study, we instead compare the case of two giant planets with nearly identical equilibrium temperature (TeqT_\mathrm{eq} ∼1050 K\sim 1050 \, \mathrm{K}) and gravity (g∼10 m s−1)g \sim 10 \, \mathrm{m \, s}^{-1}). During HSTHST Cycle 23, we collected WFC3/G141 observations of the two planets, WASP-67 b and HAT-P-38 b. HAT-P-38 b, with mass 0.42 MJ_\mathrm{J} and radius 1.4 RJR_\mathrm{J}, exhibits a relatively clear atmosphere with a clear detection of water. We refine the orbital period of this planet with new observations, obtaining P=4.6403294±0.0000055 dP = 4.6403294 \pm 0.0000055 \, \mathrm{d}. WASP-67 b, with mass 0.27 MJ_\mathrm{J} and radius 0.83 RJR_\mathrm{J}, shows a more muted water absorption feature than that of HAT-P-38 b, indicating either a higher cloud deck in the atmosphere or a more metal-rich composition. The difference in the spectra supports the hypothesis that giant exoplanet atmospheres carry traces of their formation history. Future observations in the visible and mid-infrared are needed to probe the aerosol properties and constrain the evolutionary scenario of these planets.Comment: 16 pages, 17 figures, 8 tables, accepted for publication in The Astronomical Journa

    Life expectancy in Duchenne Muscular Dystrophy : reproduced individual patient data meta-analysis

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    Objective: Duchenne Muscular Dystrophy (DMD) is a rare progressive disease, which is often diagnosed in early childhood, and leads to considerably reduced life-expectancy; due to its rarity, research literature and patient numbers are limited. To fully characterise the natural history, it is crucial to obtain appropriate estimates of the life-expectancy and mortality rates of patients with DMD. Methods: A systematic review of the published literature on mortality in DMD up until July 2020 was undertaken, specifically focusing on publications in which Kaplan-Meier (KM) survival curves with age as a time-scale were presented. These were digitised and individual patient data (IPD) reconstructed. The pooled IPD were analysed using the Kaplan-Meier estimator and parametric survival analysis models. Estimates were also stratified by birth cohort. Results: Of 1177 articles identified, 14 publications met the inclusion criteria and provided data on 2283 patients, of whom 1049 had died. Median life-expectancy was 22.0 years (95% CI: 21.2, 22.4). Analyses stratifying by three time-periods in which patients were born showed markedly increased life-expectancy in more recent patient populations; patients born after 1990 have a median life-expectancy of 28.1 years (95% CI 25.1, 30.3). Conclusions: This paper presents a full overview of mortality across the lifetime of a patient with DMD, and highlights recent improvements in survival. In the absence of large-scale prospective cohort studies or trials reporting mortality data for patients with DMD, extraction of IPD from the literature provides a viable alternative to estimating life-expectancy for this patient population
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