6,457 research outputs found

    Use and abuse of statistics in tobacco industry-funded research on standardised packaging

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    In this commentary we consider the validity of tobacco industry-funded research on the effects of standardised packaging in Australia. As the first country to introduce standardised packs, Australia is closely watched, and Philip Morris International has recently funded two studies into the impact of the measure on smoking prevalence. Both of these papers are flawed in conception as well as design but have nonetheless been widely publicised as cautionary tales against standardised pack legislation. Specifically, we focus on the low statistical significance of the analytical methods used and the assumption that standardised packaging should have an immediate large impact on smoking prevalence

    The Midspan studies

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    Effectiveness of a social support intervention on infant feeding practices : randomised controlled trial

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    Background: To assess whether monthly home visits from trained volunteers could improve infant feeding practices at age 12 months, a randomised controlled trial was carried out in two disadvantaged inner city London boroughs. Methods: Women attending baby clinics with their infants (312) were randomised to receive monthly home visits from trained volunteers over a 9-month period (intervention group) or standard professional care only (control group). The primary outcome was vitamin C intakes from fruit. Secondary outcomes included selected macro and micro-nutrients, infant feeding habits, supine length and weight. Data were collected at baseline when infants were aged approximately 10 weeks, and subsequently when the child was 12 and 18 months old. Results: Two-hundred and twelve women (68%) completed the trial. At both follow-up points no significant differences were found between the groups for vitamin C intakes from fruit or other nutrients. At first follow-up, however, infants in the intervention group were significantly less likely to be given goats’ or soya milks, and were more likely to have three solid meals per day. At the second follow-up, intervention group children were significantly less likely to be still using a bottle. At both follow-up points, intervention group children also consumed significantly more specific fruit and vegetables. Conclusions: Home visits from trained volunteers had no significant effect on nutrient intakes but did promote some other recommended infant feeding practices

    Improving the Representation and Conversion of Mathematical Formulae by Considering their Textual Context

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    Mathematical formulae represent complex semantic information in a concise form. Especially in Science, Technology, Engineering, and Mathematics, mathematical formulae are crucial to communicate information, e.g., in scientific papers, and to perform computations using computer algebra systems. Enabling computers to access the information encoded in mathematical formulae requires machine-readable formats that can represent both the presentation and content, i.e., the semantics, of formulae. Exchanging such information between systems additionally requires conversion methods for mathematical representation formats. We analyze how the semantic enrichment of formulae improves the format conversion process and show that considering the textual context of formulae reduces the error rate of such conversions. Our main contributions are: (1) providing an openly available benchmark dataset for the mathematical format conversion task consisting of a newly created test collection, an extensive, manually curated gold standard and task-specific evaluation metrics; (2) performing a quantitative evaluation of state-of-the-art tools for mathematical format conversions; (3) presenting a new approach that considers the textual context of formulae to reduce the error rate for mathematical format conversions. Our benchmark dataset facilitates future research on mathematical format conversions as well as research on many problems in mathematical information retrieval. Because we annotated and linked all components of formulae, e.g., identifiers, operators and other entities, to Wikidata entries, the gold standard can, for instance, be used to train methods for formula concept discovery and recognition. Such methods can then be applied to improve mathematical information retrieval systems, e.g., for semantic formula search, recommendation of mathematical content, or detection of mathematical plagiarism.Comment: 10 pages, 4 figure

    Dark Matter and Baryon Fraction at the Virial Radius in Abell 2256

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    We combine ASCA and ROSAT X-ray data to constrain the radial dark matter distribution in the primary cluster of A2256, free from the isothermality assumption. Both instruments indicate that the temperature declines with radius. The region including the central galaxy has a multicomponent spectrum, which results in a wide range of allowed central temperatures. We find that the secondary subcluster has a temperature and luminosity typical of a rich cluster; however, the ASCA temperature map shows no signs of an advanced merger. It is therefore assumed that the primary cluster is in hydrostatic equilibrium. The data then require dark matter density profiles steeper than rho ~ r^-2.5 in its outer part. Acceptable models have a total mass within r=1.5 Mpc (the virial radius) of 6.0+-1.5 10^14 Msun at the 90% confidence, about 1.6 times smaller than the mass derived assuming isothermality. Near the center, dark matter profiles with and without central cusps are consistent with the data. Total mass inside the X-ray core (r=0.26 Mpc) is 1.28+-0.08 10^14 Msun, which exceeds the isothermal value by a factor of 1.4. Although the confidence intervals above may be underestimates since they do not include possible asymmetry and departures from hydrostatic equilibrium, the behavior of the mass distribution, if applicable to other clusters, can bring into better agreement X-ray and lensing mass estimates, but aggravate the ``baryon catastrophe''. The observed considerable increase in the gas content with radius, not anticipated by simulations, may imply that a significant fraction of thermal gas energy comes from sources other than gravity and merger shocks.Comment: Added dynamic argument against advanced merger. Latex, 10 pages, 3 figures; uses emulateapj.sty. ApJ in pres

    M.I.T./Canadian Vestibular Experiments on the Spacelab-1 Mission. Part 1: Sensory Adaptation to Weightlessness and Readaptation to One-G: An Overview

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    Experiments on human spatial orientation were conducted on four crewmembers of Space Shuttle Spacelab Mission 1. The conceptual background of the project, the relationship among the experiments, and their relevance to a 'sensory reinterpretation hypothesis' are presented. Detailed experiment procedures and results are presented in the accompanying papers in this series. The overall findings are discussed as they pertain to the following aspects of hypothesized sensory reinterpretation in weightlessness: (1) utricular otolith afferent signals are reinterpreted as indicating head translation rather than tilt, (2) sensitivity of reflex responses to footward acceleration is reduced, and (3) increased weighting is given to visual and tactile cues in orientation perception and posture control. Results suggest increased weighting of visual cues and reduced weighting of graviceptor signals in weightlessness
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