6,042 research outputs found

    LASR-Guided Stellar Photometric Variability Subtraction: The Linear Algorithm For Significance Reduction

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    We develop a technique for removing stellar variability in the light curves of δ\delta-Scuti and similar stars. Our technique, which we name the Linear Algorithm for Significance Reduction (LASR), subtracts oscillations from a time series by minimizing their statistical significance in frequency space. We demonstrate that LASR can subtract variable signals of near-arbitrary complexity and can robustly handle close frequency pairs and overtone frequencies. We demonstrate that our algorithm performs an equivalent fit as prewhitening to the straightforward variable signal of KIC 9700322. We also show that LASR provides a better fit to seismic activity than prewhitening in the case of the complex δ\delta-Scuti KOI-976.Comment: 9 pages, 5 figures, accepted for publication in Astronomy & Astrophysics. Pseudocode and github link to code included in manuscrip

    A Note on Estimating the Cost of Capital for the Undiversified Business Owner

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    About 70 percent of businesses are organized as sole proprietorships, and many business owners are not well-diversified, yet the finance discipline is largely silent regarding how to estimate the opportunity cost of capital for undiversified investors. In this paper, the Capital Market Line (CML) is presented as the appropriate vehicle for estimating such an investor’s return requirement. Recognizing the applicability of the CML allows the undiversified investor’s exposure to an investment’s total risk to be objectively linked to the market price of risk. Knowing the appropriate return requirement is useful for valuation and capital budgeting purposes

    Sudan Pasturage for Beef Production.

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    12 p

    Inconsistency of threat level in soft armour standards, correlation of experimental tests to bullet X-ray 3D images

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    Fundamental to any ballistic armour standard is the reference projectile that is to be defeated. Typically, for certification, consistency of bullet geometry is assumed. Therefore, practical variations in bullet jacket dimensions can have far reaching consequences. Traditionally, internal dimensions have been analysed by physically sectioning bullets – an approach which rules out any subsequent ballistic assessment. The use of a non-destructive X-ray Computed Tomography (CT) method was demonstrated in [1]. Now, the authors apply this technique to correlate bullet impact response to jacket thickness variations. A set of 20 bullets (9 mm DM 11) was selected to analyse both intra and inter bullet variations using an image based analysis method to map the jacket thickness and measure the centre of gravity. Thickness variations of the order of 200μm were found commonly across all the bullets along the length and an angular variation of up to 50μm was found in a few bullets. The bullets were subsequently impacted against a rigid flat plate and re-scanned. The results of the experiments are shown and compared to the un-deformed bullet jacket thickness variations. The conclusions are relevant for future soft armour standards and provide important data for numerical model correlation and development

    Ethyl 2-(5-bromo-2-iodo­anilino)cyclo­pent-1-ene-1-carboxyl­ate

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    Acknowledgements We thank the EPSRC National Crystallography Service (University of Southampton) for the data collection.Peer reviewedPublisher PD

    Development and Validation of eRADAR: A Tool Using EHR Data to Detect Unrecognized Dementia.

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    ObjectivesEarly recognition of dementia would allow patients and their families to receive care earlier in the disease process, potentially improving care management and patient outcomes, yet nearly half of patients with dementia are undiagnosed. Our aim was to develop and validate an electronic health record (EHR)-based tool to help detect patients with unrecognized dementia (EHR Risk of Alzheimer's and Dementia Assessment Rule [eRADAR]).DesignRetrospective cohort study.SettingKaiser Permanente Washington (KPWA), an integrated healthcare delivery system.ParticipantsA total of 16 665 visits among 4330 participants in the Adult Changes in Thought (ACT) study, who undergo a comprehensive process to detect and diagnose dementia every 2 years and have linked KPWA EHR data, divided into development (70%) and validation (30%) samples.MeasurementsEHR predictors included demographics, medical diagnoses, vital signs, healthcare utilization, and medications within the previous 2 years. Unrecognized dementia was defined as detection in ACT before documentation in the KPWA EHR (ie, lack of dementia or memory loss diagnosis codes or dementia medication fills).ResultsOverall, 1015 ACT visits resulted in a diagnosis of incident dementia, of which 498 (49%) were unrecognized in the KPWA EHR. The final 31-predictor model included markers of dementia-related symptoms (eg, psychosis diagnoses, antidepressant fills), healthcare utilization pattern (eg, emergency department visits), and dementia risk factors (eg, cerebrovascular disease, diabetes). Discrimination was good in the development (C statistic = .78; 95% confidence interval [CI] = .76-.81) and validation (C statistic = .81; 95% CI = .78-.84) samples, and calibration was good based on plots of predicted vs observed risk. If patients with scores in the top 5% were flagged for additional evaluation, we estimate that 1 in 6 would have dementia.ConclusionThe eRADAR tool uses existing EHR data to detect patients with good accuracy who may have unrecognized dementia. J Am Geriatr Soc 68:103-111, 2019

    Substance Use Among Asian American Adolescents: Perceptions of Use and Preferences for Prevention Programming

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    Rarely has substance use prevention programming targeted Asian-American adolescents. Using a focus group methodology, we explored perceptions of substance use and preferences for prevention programming among 31 Asian-American adolescents in New York City. Participants considered substance use common in the community. Factors contributing to substance use among Asian-American adolescents (e.g., peer pressure, pressure to achieve, family factors, and community influence) were identified, and the need for prevention programs tailored for the Asian-American community was highlighted. Participants discussed preferred program content, delivery settings, and recruitment and retention strategies. Despite the favorable attitude for family-based prevention programming, participants raised potential issues concerning the feasibility of such a program. Study findings facilitate understanding of Asian-American adolescents\u27 substance use behavior and shed light on prevention program development for this underserved population

    Calculations of periodicity from H<i>α</i> profiles of Proxima Centauri

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    We investigate retrieval of the stellar rotation signal for Proxima Centauri. We make use of high-resolution spectra taken with UVES and HARPS of Proxima Centauri over a 13-yr period as well as photometric observations of Proxima Centauri from ASAS and HST. We measure the Hα equivalent width and Hα index, skewness and kurtosis and introduce a method that investigates the symmetry of the line, the peak ratio, which appears to return better results than the other measurements. Our investigations return a most significant period of 82.6 ± 0.1 days, confirming earlier photometric results and ruling out a more recent result of 116.6 days which we conclude to be an alias induced by the specific HARPS observation times. We conclude that whilst spectroscopic Hα measurements can be used for period recovery, in the case of Proxima Centauri the available photometric measurements are more reliable. We make 2D models of Proxima Centauri to generate simulated Hα, finding that reasonable distributions of plage and chromospheric features are able to reproduce the equivalent width variations in observed data and recover the rotation period, including after the addition of simulated noise and flares. However the 2D models used fail to generate the observed variety of line shapes measured by the peak ratio. We conclude that only 3D models which incorporate vertical motions in the chromosphere can achieve this
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