557 research outputs found

    Spectral and Imaging Diagnostics of Spatially-Extended Turbulent Electron Acceleration and Transport in Solar Flares

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    Solar flares are efficient particle accelerators with a large fraction of released magnetic energy (10-50%) converted into energetic particles such as hard X-ray producing electrons. This energy transfer process is not well constrained, with competing theories regarding the acceleration mechanism(s), including MHD turbulence. We perform a detailed parameter study examining how various properties of the acceleration region, including its spatial extent and the spatial distribution of turbulence, affect the observed electron properties, such as those routinely determined from X-ray imaging and spectroscopy. Here, a time-independent Fokker-Planck equation is used to describe the acceleration and transport of flare electrons through a coronal plasma of finite temperature. Motivated by recent non-thermal line broadening observations that suggested extended regions of turbulence in coronal loops, an extended turbulent acceleration region is incorporated into the model. We produce outputs for the density weighted electron flux, a quantity directly related to observed X-rays, modelled in energy and space from the corona to chromosphere. We find that by combining several spectral and imaging diagnostics (such as spectral index differences or ratios, energy or spatial-dependent flux ratios, and electron depths into the chromosphere) the acceleration properties, including the timescale and velocity dependence, can be constrained alongside the spatial properties. Our diagnostics provide a foundation for constraining the properties of acceleration in an individual flare from X-ray imaging spectroscopy alone, and can be applied to past, current and future observations including those from RHESSI and Solar Orbiter.Comment: ApJ Accepte

    Internal Medicine residents use heuristics to estimate disease probability

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    Background: Training in Bayesian reasoning may have limited impact on accuracy of probability estimates. In this study, our goal was to explore whether residents previously exposed to Bayesian reasoning use heuristics rather than Bayesian reasoning to estimate disease probabilities. We predicted that if residents use heuristics then post-test probability estimates would be increased by non-discriminating clinical features or a high anchor for a target condition.Method: We randomized 55 Internal Medicine residents to different versions of four clinical vignettes and asked them to estimate probabilities of target conditions. We manipulated the clinical data for each vignette to be consistent with either 1) using a representative heuristic, by adding non-discriminating prototypical clinical features of the target condition, or 2) using anchoring with adjustment heuristic, by providing a high or low anchor for the target condition.Results:  When presented with additional non-discriminating data the odds of diagnosing the target condition were increased (odds ratio (OR) 2.83, 95% confidence interval [1.30, 6.15], p = 0.009). Similarly, the odds of diagnosing the target condition were increased when a high anchor preceded the vignette (OR 2.04, [1.09, 3.81], p = 0.025).Conclusions: Our findings suggest that despite previous exposure to the use of Bayesian reasoning, residents use heuristics, such as the representative heuristic and anchoring with adjustment, to estimate probabilities. Potential reasons for attribute substitution include the relative cognitive ease of heuristics vs. Bayesian reasoning or perhaps residents in their clinical practice use gist traces rather than precise probability estimates when diagnosing

    Exploring fathering roles in low-income families: The influence of intergenerational transmission

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    This is the published version. Copyright Alliance for Children and FamiliesThis study explores the meaning of fathering among men identified as fathers or father figures of 24-month-old children enrolled in Early Head Start research sites. Fathers were asked open-ended questions about their experiences of being fathers and their relationships with their own fathers. These men spoke of how important “being there” was for them in their relationship with their child as well as how the relationship with their own fathers influenced them as a parent. This study supports the theory of intergenerational parenting and furthers our knowledge and understanding of what some men feel are important aspects of being a good father. A theoretical framework on why men may model their father’s behaviors is offered, as are implications for practitioners

    Natural Gas Development: Views of New York and Pennsylvania Residents in the Marcellus Shale Region

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    CaRDI Research & Policy Brief Issue 39; Community & Energy: Nonrenewable Energy Production and Developmen

    How Do Data Analysts Respond to AI Assistance? A Wizard-of-Oz Study

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    Data analysis is challenging as analysts must navigate nuanced decisions that may yield divergent conclusions. AI assistants have the potential to support analysts in planning their analyses, enabling more robust decision making. Though AI-based assistants that target code execution (e.g., Github Copilot) have received significant attention, limited research addresses assistance for both analysis execution and planning. In this work, we characterize helpful planning suggestions and their impacts on analysts' workflows. We first review the analysis planning literature and crowd-sourced analysis studies to categorize suggestion content. We then conduct a Wizard-of-Oz study (n=13) to observe analysts' preferences and reactions to planning assistance in a realistic scenario. Our findings highlight subtleties in contextual factors that impact suggestion helpfulness, emphasizing design implications for supporting different abstractions of assistance, forms of initiative, increased engagement, and alignment of goals between analysts and assistants.Comment: Accepted to CHI 202

    Identification of novel pathways of osimertinib disposition and potential implications for the outcome of lung cancer therapy

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    Abstract Purpose: Osimertinib is a third-generation inhibitor of the epidermal growth factor receptor used in treatment of non–small cell lung cancer. A full understanding of its disposition and capacity for interaction with other medications will facilitate its effective use as a single agent and in combination therapy. Experimental Design: Recombinant cytochrome P450s and liver microsomal preparations were used to identify novel pathways of osimertinib metabolism in vitro. A panel of knockout and mouse lines humanized for pathways of drug metabolism were used to establish the relevance of these pathways in vivo. Results: Although some osimertinib metabolites were similar in mouse and human liver samples there were several significant differences, in particular a marked species difference in the P450s involved. The murine Cyp2d gene cluster played a predominant role in mouse, whereas CYP3A4 was the major human enzyme responsible for osimertinib metabolism. Induction of this enzyme in CYP3A4 humanized mice substantially decreased circulating osimertinib exposure. Importantly, we discovered a further novel pathway of osimertinib disposition involving CPY1A1. Modulation of CYP1A1/CYP1A2 levels markedly reduced parent drug concentrations, significantly altering metabolite pharmacokinetics (PK) in humanized mice in vivo. Conclusions: We demonstrate that a P450 enzyme expressed in smokers' lungs and lung tumors has the capacity to metabolise osimertinib. This could be a significant factor in defining the outcome of osimertinib treatment. This work also illustrates how P450-humanized mice can be used to identify and mitigate species differences in drug metabolism and thereby model the in vivo effect of critical metabolic pathways on anti-tumor response. Clin Cancer Res; 24(9); 2138–47. ©2018 AACR.</jats:p

    Design and evaluation of the ReKon : an integrated detection and assessment perimeter system.

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    Kontek Industries (Kannapolis, NC) and their subsidiary, Stonewater Control Systems (Kannapolis, NC), have entered into a cooperative research and development agreement with Sandia to jointly develop and evaluate an integrated perimeter security system solution, one that couples access delay with detection and assessment. This novel perimeter solution was designed to be configurable for use at facilities ranging from high-security military sites to commercial power plants, to petro/chemical facilities of various kinds. A prototype section of the perimeter has been produced and installed at the Sandia Test and Evaluation Center in Albuquerque, NM. This prototype system integrated fiber optic break sensors, active infrared sensors, fence disturbance sensors, video motion detection, and ground sensors. This report documents the design, testing, and performance evaluation of the developed ReKon system. The ability of the system to properly detect pedestrian or vehicle attempts to bypass, breach, or otherwise defeat the system is characterized, as well as the Nuisance Alarm Rate

    Residents\u27 Perceptions of Community and Environmental Impacts From Development of Natural Gas in the Marcellus Shale: A Comparison of Pennsylvania and New York Cases

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    Communities experiencing rapid growth due to energy development (‘boomtowns’) have reported positive and negative impacts on community and individual well-being. The perceptions of impacts vary according to stage of energy development as well as experience with extractive industries. Development of the Marcellus Shale provides an opportunity to examine these impacts over time and across geographic and historical contexts. This paper describes case study research in Pennsylvania and New York to document preliminary impacts of development occurring there. Cases vary by level of development and previous extractive history. The study finds that, in areas with low population density, higher levels of development lead to a broader awareness of natural gas impacts, both positive and negative. Participants draw from the regional history of extraction to express environmental concern despite direct, local experience. Our findings suggest the need to track these perceptions during development, and as individuals and communities react and adapt to the impacts
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