867 research outputs found

    IUE observations of the 1987 superoutburst of the dwarf nova Z Cha

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    Low resolution IUE observations of the dwarf nova Z Cha during superoutburst are presented. These cover most of the development of the outburst and have sufficient time resolution to probe continuum and line behavior on orbital phase. The observed modulation on this phase is very similar to that observed in the related object OY Car. The results imply the presence of a cool spot on the edge of the edge of the accretion disk, which periodically occults the brighter inner disk. Details of the line behavior suggest that the line originated in an extended wind-emitting region. In contrast to archive spectra obtained in normal outburst, the continuum is fainter and redder, indicating that the entire superoutburst disk may be geometrically thicker than during a normal outburst

    We are more selfish than we think:The endowment effect and reward processing within the human medial-frontal cortex

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    Perceived ownership has been shown to impact a variety of cognitive processes: attention, memory, and—more recently—reward processing. In the present experiment we examined whether or not perceived ownership would interact with the construct of value—the relative worth of an object. Participants completed a simple gambling game in which they gambled either for themselves or for another while electroencephalographic data were recorded. In a key manipulation, gambles for oneself or for another were for either small or large rewards. We tested the hypothesis that value affects the neural response to self-gamble outcomes, but not other-gamble outcomes. Our experimental data revealed that while participants learned the correct response option for both self and other gambles, the reward positivity evoked by wins was impacted by value only when gambling for oneself. Importantly, our findings provide additional evidence for a self-ownership bias in cognitive processing and further demonstrate the insensitivity of the medial-frontal reward system to gambles for another. </jats:p

    Projecting the Contribution of Provitamin A Maize Biofortification and Other Nutrition Interventions to the Nutritional Adequacy and Cost of Diets in Rural Zimbabwe

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    Background Evidence of the effectiveness of biofortified maize with higher provitamin A (PVA) to address vitamin A deficiency in rural Africa remains scant. Objectives This study projects the impact of adopting PVA maize for a diversity of households in an area typical of rural Zimbabwe and models the cost and composition of diets adequate in vitamin A. Methods Household-level weighed food records were generated from 30 rural households during a week in April and November 2021. Weekly household intakes were calculated, as well as indicative costs of diets using data from market surveys. The impact of PVA maize adoption was modeled assuming all maize products contained observed vitamin A concentrations. The composition and cost of the least expensive indicative diets adequate in vitamin A were calculated using linear programming. Results Very few households would reach adequate intake of vitamin A with the consumption of PVA maize. However, from a current situation of 33%, 50%–70% of households were projected to reach ≤50% of their requirements (the target of PVA), even with the modest vitamin A concentrations achieved on-farm (mean of 28.3 μg RAE per 100 g). This proportion would increase if higher concentrations recorded on-station were achieved. The estimated daily costs of current diets (mean ± standard deviation) were USD 1.43 ± 0.59 in the wet season and USD 0.96 ± 0.40 in the dry season. By comparison, optimization models suggest that diets adequate in vitamin A could be achieved at daily costs of USD 0.97 and USD 0.79 in the wet and dry seasons, respectively. Conclusions The adoption of PVA maize would bring a substantial improvement in vitamin A intake in rural Zimbabwe but should be combined with other interventions (e.g., diet diversification) to fully address vitamin A deficienc

    Facilitating the elicitation of beliefs for use in Bayesian Belief modelling

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    Expert opinion is increasingly being used to inform Bayesian Belief Networks, in particular to define the conditional dependencies modelled by the graphical structure. The elicitation of such expert opinion remains a major challenge due to both the quantity of information required and the ability of experts to quantify subjective beliefs effectively. In this work, we introduce a method designed to initialise conditional probability tables based on a small number of simple questions that capture the overall shape of a conditional probability distribution before enabling the expert to refine their results in an efficient way. These methods have been incorporated into a software Application for Conditional probability Elicitation (ACE), freely available at https://github.com/KirstyLHassall/ACE Hassall (2019

    The role of cisapride in the treatment of pediatric gastroesophageal reflux.

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