594 research outputs found

    Exact Bayesian curve fitting and signal segmentation.

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    We consider regression models where the underlying functional relationship between the response and the explanatory variable is modeled as independent linear regressions on disjoint segments. We present an algorithm for perfect simulation from the posterior distribution of such a model, even allowing for an unknown number of segments and an unknown model order for the linear regressions within each segment. The algorithm is simple, can scale well to large data sets, and avoids the problem of diagnosing convergence that is present with Monte Carlo Markov Chain (MCMC) approaches to this problem. We demonstrate our algorithm on standard denoising problems, on a piecewise constant AR model, and on a speech segmentation problem

    Vitamins and minerals: issues associated with too low and too high population intakes

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    There is an ongoing increase in the availability of foods fortified with micronutrients and dietary supplements. This may result in differing intakes of micronutrients within the population and perhaps larger differences in intakes. Insight into population micronutrient intakes and evaluation of too low or too high intakes is required to see whether there are potential problems regarding inadequacy or excessive intakes. Too low population intakes are evaluated against an estimated average requirement; potential too high population intakes are evaluated against a tolerable upper intake level (UL). Additional health effects, seriousness, and incidence of these health effects are not considered but these can be taken into account in a benefit-risk assessment. Furthermore, authorities would like to regulate food fortification and supplementation in such a way that most of the population is not at risk of potentially high intakes. Several models are available for estimating maximum levels of micronutrients for food fortification and dietary supplements. Policy makers and risk managers need to decide how to divide the ‘free space’ between food fortification and/or dietary supplements, while protecting populations from adverse health effects

    EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA); Scientific Opinion on principles for deriving and applying Dietary Reference Values

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    This Opinion of the EFSA Panel on Dietetic products, Nutrition, and Allergies (NDA) deals with the general principles for development and application of Dietary Reference Values (DRVs). These quantitative reference values for nutrient intakes for healthy individuals and populations are based on health criteria. Derived from DRVs, nutrients goals and recommendations take into account other criteria such as food composition or dietary habits, and may be used for assessment and planning of diets. It is proposed to derive the following DRVs: 1) Population Reference Intakes (PRI), 2) Average Requirement (AR), 3) Lower Threshold Intake (LTI), 4) Adequate Intake (AI), 5) Reference Intake ranges for macronutrients (RI). Nutrient requirements differ with age, sex and physiological condition. The Panel proposes to define the age ranges used for each nutrient on a case-by-case basis depending on the available data. For the age group < 6 months requirements are considered to be equal to the supply from breast- milk, except in those cases where this does not apply. Separate reference values will be established for pregnant and lactating women. Interpolation or extrapolation between population groups will be used in instances where no data are available for defined age and sex groups

    Breast-milk iodine concentration declines over the first 6 mo postpartum in iodine-deficient women.

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    BACKGROUND: Little is known about the iodine status of lactating mothers and their infants during the first 6 mo postpartum or, if deficient, the amount of supplemental iodine required to improve status. OBJECTIVE: The objective was to determine maternal and infant iodine status and the breast-milk iodine concentration (BMIC) over the first 6 mo of breastfeeding. DESIGN: A randomized, double-blind, placebo-controlled supplementation trial was conducted in lactating women who received placebo (n = 56), 75 ÎŒg I/d (n = 27), or 150 ÎŒg I/d (n = 26) after their infants' birth until 24 wk postpartum. Maternal and infant urine samples and breast-milk samples were collected at 1, 2, 4, 8, 12, 16, 20, and 24 wk. Maternal serum thyrotropin and free thyroxine concentrations were measured at 24 wk. RESULTS: Over 24 wk, the median urinary iodine concentration (UIC) of unsupplemented women and their infants ranged from 20 to 41 ÎŒg/L and 34 to 49 ÎŒg/L, respectively, which indicated iodine deficiency (ie, UIC < 100 ÎŒg/L). Mean maternal UIC was 2.1-2.4 times higher in supplemented than in unsupplemented women (P < 0.001) but did not differ significantly between the 2 supplemented groups. BMIC in the placebo group decreased by 40% over 24 wk (P < 0.001) and was 1.3 times and 1.7 times higher in women supplemented with 75 ÎŒg I/d (P = 0.030) and 150 ÎŒg I/d (P < 0.001), respectively, than in unsupplemented women. Thyrotropin and free thyroxine did not differ significantly between groups. CONCLUSION: BMIC decreased in the first 6 mo in these iodine-deficient lactating women; supplementation with 75 or 150 ÎŒg I/d increased the BMIC but was insufficient to ensure adequate iodine status in women or their infants. The study was registered with the Australian New Zealand Clinical Trials Registry as ACTRN12605000345684

    Conducting Science in Disasters: Recommendations from the NIEHS Working Group for Special IRB Considerations in the Review of Disaster Related Research.

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    Research involving human subjects after public health emergencies and disasters may pose ethical challenges. These challenges may include concerns about the vulnerability of prospective disaster research participants, increased research burden among disaster survivors approached by multiple research teams, and potentially reduced standards in the ethical review of research by institutional review boards (IRBs) due to the rush to enter the disaster field. The NIEHS Best Practices Working Group for Special IRB Considerations in the Review of Disaster Related Research was formed to identify and address ethical and regulatory challenges associated with the review of disaster research. The working group consists of a diverse collection of disaster research stakeholders across a broad spectrum of disciplines. The working group convened in July 2016 to identify recommendations that are instrumental in preparing IRBs to review protocols related to public health emergencies and disasters. The meeting included formative didactic presentations and facilitated breakout discussions using disaster-related case studies. Major thematic elements from these discussions were collected and documented into 15 working group recommendations, summarized in this article, that address topics such as IRB disaster preparedness activities, informed consent, vulnerable populations, confidentiality, participant burden, disaster research response integration and training, IRB roles/responsibilities, community engagement, and dissemination of disaster research results. https://doi.org/10.1289/EHP237

    Sharing clinical research data in the United States under the health insurance portability and accountability act and the privacy rule

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    Sharing of final research data from clinical research is an essential part of the scientific method. The U.S. National Institutes of Health require some grant applications to include plans for sharing final research data, which it defines as the factual materials necessary to document, support, and validate research findings. In the U.S., however, the Privacy Rule adopted under the Health Insurance Portability and Accountability Act impedes the sharing of final research data. In most situations, final research data may be shared only where all information that could possibly be used to identify the subject has been deleted, or where the subject has given authorization for specific research, or an Institutional Review Board has granted a waiver

    Student engagement as a function of environmental complexity in high school classrooms

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    The purpose of this study was to investigate the linkage between the quality of the learning environment and the quality of students' experience in seven high school classrooms in six different subject areas. The quality of the learning environment was conceptualized in terms of environmental complexity, or the simultaneous presence of environmental challenge and environmental support. The students (N = 108) in each class participated in the Experience Sampling Method (ESM) measuring their engagement and related experiential variables. Concurrently, environmental complexity and its subdimensions were observed and rated from video with a new observational instrument, The Optimal Learning Environments - Observational Log and Assessment (OLE-OLA). Using two-level HLM regression models, ratings from the OLE-OLA were utilized to predict student engagement and experiential variables as measured by the ESM. Results showed that environmental complexity predicted student engagement and sense of classroom self-esteem. Implications for research, theory and practice are discussed

    Personal service assistance: Musculoskeletal disorders and injuries in consumer-directed home care

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    BackgroundLike other types of care for disabled or elderly adults, consumer-directed personal assistance services may present multi-factorial risks for work-related musculoskeletal disorders (WRMSDs).MethodsUsing survey data, we compared providers experiencing WRMSDs in the previous year to those who did not, seeking to identify functional, temporal, physical, and relationship risk factors for transient and chronic conditions.ResultsLonger work experience with the recipient and more frequent bending increased the risk of being in the most chronic group (≄12 painful episodes), whereas predictable work hours with rest breaks and greater social support from the recipient appeared protective. For transient conditions (one to two episodes), longer work experience with the recipient and predictable hours with rest breaks appeared protective.ConclusionsWe offer recommendations to improve hazard assessment as well as training and information distribution related to home care programs. With the population aging, home care jobs require increasing oversight to prevent WRMSDs
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