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Sample records for prevalences confidence intervals

  1. Using the confidence interval confidently.

    Science.gov (United States)

    Hazra, Avijit

    2017-10-01

    Biomedical research is seldom done with entire populations but rather with samples drawn from a population. Although we work with samples, our goal is to describe and draw inferences regarding the underlying population. It is possible to use a sample statistic and estimates of error in the sample to get a fair idea of the population parameter, not as a single value, but as a range of values. This range is the confidence interval (CI) which is estimated on the basis of a desired confidence level. Calculation of the CI of a sample statistic takes the general form: CI = Point estimate ± Margin of error, where the margin of error is given by the product of a critical value (z) derived from the standard normal curve and the standard error of point estimate. Calculation of the standard error varies depending on whether the sample statistic of interest is a mean, proportion, odds ratio (OR), and so on. The factors affecting the width of the CI include the desired confidence level, the sample size and the variability in the sample. Although the 95% CI is most often used in biomedical research, a CI can be calculated for any level of confidence. A 99% CI will be wider than 95% CI for the same sample. Conflict between clinical importance and statistical significance is an important issue in biomedical research. Clinical importance is best inferred by looking at the effect size, that is how much is the actual change or difference. However, statistical significance in terms of P only suggests whether there is any difference in probability terms. Use of the CI supplements the P value by providing an estimate of actual clinical effect. Of late, clinical trials are being designed specifically as superiority, non-inferiority or equivalence studies. The conclusions from these alternative trial designs are based on CI values rather than the P value from intergroup comparison.

  2. Robust misinterpretation of confidence intervals

    NARCIS (Netherlands)

    Hoekstra, Rink; Morey, Richard; Rouder, Jeffrey N.; Wagenmakers, Eric-Jan

    2014-01-01

    Null hypothesis significance testing (NHST) is undoubtedly the most common inferential technique used to justify claims in the social sciences. However, even staunch defenders of NHST agree that its outcomes are often misinterpreted. Confidence intervals (CIs) have frequently been proposed as a more

  3. Comparing geographic area-based and classical population-based incidence and prevalence rates, and their confidence intervals

    Directory of Open Access Journals (Sweden)

    Ding-Geng Chen

    2017-09-01

    Full Text Available To quantify the HIV epidemic, the classical population-based prevalence and incidence rates (P rates are the two most commonly used measures used for policy interventions. However, these P rates ignore the heterogeneity of the size of geographic region where the population resides. It is intuitive that with the same P rates, the likelihood for HIV can be much greater to spread in a population residing in a crowed small urban area than the same number of population residing in a large rural area. With this limitation, Chen and Wang (2017 proposed the geographic area-based rates (G rates to complement the classical P rates. They analyzed the 2000–2012 US data on new HIV infections and persons living with HIV and found, as compared with other methods, using G rates enables researchers to more quickly detect increases in HIV rates. This capacity to reveal increasing rates in a more efficient and timely manner is a crucial methodological contribution to HIV research. To enhance this newly proposed concept of G rates, this article presents a discussion of 3 areas for further development of this important concept: (1 analysis of global HIV epidemic data using the newly proposed G rates to capture the changes globally; (2 development of the associated population density-based rates (D rates to incorporate the heterogeneities from both geographical area and total population-at-risk; and (3 development of methods to calculate variances and confidence intervals for the P rates, G rates, and D rates to capture the variability of these indices.

  4. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, Richard D.; Hoekstra, Rink; Rouder, Jeffrey N.; Lee, Michael D.; Wagenmakers, Eric-Jan

    2016-01-01

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  5. The fallacy of placing confidence in confidence intervals

    NARCIS (Netherlands)

    Morey, R.D.; Hoekstra, R.; Rouder, J.N.; Lee, M.D.; Wagenmakers, E.-J.

    Interval estimates – estimates of parameters that include an allowance for sampling uncertainty – have long been touted as a key component of statistical analyses. There are several kinds of interval estimates, but the most popular are confidence intervals (CIs): intervals that contain the true

  6. Confidence Interval Approximation For Treatment Variance In ...

    African Journals Online (AJOL)

    In a random effects model with a single factor, variation is partitioned into two as residual error variance and treatment variance. While a confidence interval can be imposed on the residual error variance, it is not possible to construct an exact confidence interval for the treatment variance. This is because the treatment ...

  7. Interpretation of Confidence Interval Facing the Conflict

    Science.gov (United States)

    Andrade, Luisa; Fernández, Felipe

    2016-01-01

    As literature has reported, it is usual that university students in statistics courses, and even statistics teachers, interpret the confidence level associated with a confidence interval as the probability that the parameter value will be between the lower and upper interval limits. To confront this misconception, class activities have been…

  8. Nonparametric confidence intervals for monotone functions

    NARCIS (Netherlands)

    Groeneboom, P.; Jongbloed, G.

    2015-01-01

    We study nonparametric isotonic confidence intervals for monotone functions. In [Ann. Statist. 29 (2001) 1699–1731], pointwise confidence intervals, based on likelihood ratio tests using the restricted and unrestricted MLE in the current status model, are introduced. We extend the method to the

  9. Coefficient Omega Bootstrap Confidence Intervals: Nonnormal Distributions

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin

    2013-01-01

    The performance of the normal theory bootstrap (NTB), the percentile bootstrap (PB), and the bias-corrected and accelerated (BCa) bootstrap confidence intervals (CIs) for coefficient omega was assessed through a Monte Carlo simulation under conditions not previously investigated. Of particular interests were nonnormal Likert-type and binary items.…

  10. Coefficient Alpha Bootstrap Confidence Interval under Nonnormality

    Science.gov (United States)

    Padilla, Miguel A.; Divers, Jasmin; Newton, Matthew

    2012-01-01

    Three different bootstrap methods for estimating confidence intervals (CIs) for coefficient alpha were investigated. In addition, the bootstrap methods were compared with the most promising coefficient alpha CI estimation methods reported in the literature. The CI methods were assessed through a Monte Carlo simulation utilizing conditions…

  11. Understanding Confidence Intervals With Visual Representations

    OpenAIRE

    Navruz, Bilgin; Delen, Erhan

    2014-01-01

    In the present paper, we showed how confidence intervals (CIs) are valuable and useful in research studies when they are used in the correct form with correct interpretations. The sixth edition of the APA (2010) Publication Manual strongly recommended reporting CIs in research studies, and it was described as “the best reporting strategy” (p. 34). Misconceptions and correct interpretations of CIs were presented from several textbooks. In addition, limitations of the null hypothesis statistica...

  12. Confidence intervals for annual wind power production******

    Directory of Open Access Journals (Sweden)

    Bensoussan Alain

    2014-01-01

    Full Text Available Wind power is an intermittent resource due to wind speed intermittency. However wind speed can be described as a stochastic process with short memory. This allows us to derive a central limit theorem for the annual or pluri-annual wind power production and then get quantiles of the wind power production for one, ten or twenty years future periods. On the one hand, the interquantile spread offers a measurement of the intrinsic uncertainties of wind power production. On the other hand, different quantiles with different periods of time are used by financial institutions to quantify the financial risk of the wind turbine. Our method is then applied to real datasets corresponding to a French wind turbine. Since confidence intervals can be enhanced by taking into account seasonality, we present some tools for change point analysis on wind series.

  13. Fusing photovoltaic data for improved confidence intervals

    Directory of Open Access Journals (Sweden)

    Ansgar Steland

    2017-01-01

    Full Text Available Characterizing and testing photovoltaic modules requires carefully made measurements on important variables such as the power output under standard conditions. When additional data is available, which has been collected using a different measurement system and therefore may be of different accuracy, the question arises how one can combine the information present in both data sets. In some cases one even has prior knowledge about the ordering of the variances of the measurement errors, which is not fully taken into account by commonly known estimators. We discuss several statistical estimators to combine the sample means of independent series of measurements, both under the assumption of heterogeneous variances and ordered variances. The critical issue is then to assess the estimator’s variance and to construct confidence intervals. We propose and discuss the application of a new jackknife variance estimator devised by [1] to such photovoltaic data, in order to assess the variability of common mean estimation under heterogeneous and ordered variances in a reliable and nonparametric way. When serial correlations are present, which usually a ect the marginal variances, it is proposed to construct a thinned data set by downsampling the series in such a way that autocorrelations are removed or dampened. We propose a data adaptive procedure which downsamples a series at irregularly spaced time points in such a way that the autocorrelations are minimized. The procedures are illustrated by applying them to real photovoltaic power output measurements from two different sun light flashers. In addition, focusing on simulations governed by real photovoltaic data, we investigate the accuracy of the jackknife approach and compare it with other approaches. Among those is a variance estimator based on Nair’s formula for Gaussian data and, as a parametric alternative, two Bayesian models. We investigate the statistical accuracy of the resulting confidence

  14. Confidence Intervals from Normalized Data: A correction to Cousineau (2005

    Directory of Open Access Journals (Sweden)

    Richard D. Morey

    2008-09-01

    Full Text Available Presenting confidence intervals around means is a common method of expressing uncertainty in data. Loftus and Masson (1994 describe confidence intervals for means in within-subjects designs. These confidence intervals are based on the ANOVA mean squared error. Cousineau (2005 presents an alternative to the Loftus and Masson method, but his method produces confidence intervals that are smaller than those of Loftus and Masson. I show why this is the case and offer a simple correction that makes the expected size of Cousineau confidence intervals the same as that of Loftus and Masson confidence intervals.

  15. Learning about confidence intervals with software R

    Directory of Open Access Journals (Sweden)

    Gariela Gonçalves

    2013-08-01

    Full Text Available 0 0 1 202 1111 USAL 9 2 1311 14.0 Normal 0 21 false false false ES JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:Calibri; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-ansi-language:ES; mso-fareast-language:EN-US;} This work was to study the feasibility of implementing a teaching method that employs software, in a Computational Mathematics course, involving students and teachers through the use of the statistical software R in carrying out practical work, such as strengthening the traditional teaching. The statistical inference, namely the determination of confidence intervals, was the content selected for this experience. It was intended show, first of all, that it is possible to promote, through the proposal methodology, the acquisition of basic skills in statistical inference and to promote the positive relationships between teachers and students. It presents also a comparative study between the methodologies used and their quantitative and qualitative results on two consecutive school years, in several indicators. The data used in the study were obtained from the students to the exam questions in the years 2010/2011 and 2011/2012, from the achievement of a working group in 2011/2012 and via the responses to a questionnaire (optional and anonymous also applied in 2011 / 2012. In terms of results, we emphasize a better performance of students in the examination questions in 2011/2012, the year that students used the software R, and a very favorable student’s perspective about

  16. On randomized confidence intervals for the binomial probability

    OpenAIRE

    Kabaila, Paul

    2013-01-01

    Suppose that X_1,X_2,...,X_n are independent and identically Bernoulli(theta) distributed. Also suppose that our aim is to find an exact confidence interval for theta that is the intersection of a 1-\\alpha/2 upper confidence interval and a 1-\\alpha/2 lower confidence interval. The Clopper-Pearson interval is the standard such confidence interval for theta, which is widely used in practice. We consider the randomized confidence interval of Stevens, 1950 and present some extensions, including p...

  17. Confidence Intervals: From tests of statistical significance to confidence intervals, range hypotheses and substantial effects

    Directory of Open Access Journals (Sweden)

    Dominic Beaulieu-Prévost

    2006-03-01

    Full Text Available For the last 50 years of research in quantitative social sciences, the empirical evaluation of scientific hypotheses has been based on the rejection or not of the null hypothesis. However, more than 300 articles demonstrated that this method was problematic. In summary, null hypothesis testing (NHT is unfalsifiable, its results depend directly on sample size and the null hypothesis is both improbable and not plausible. Consequently, alternatives to NHT such as confidence intervals (CI and measures of effect size are starting to be used in scientific publications. The purpose of this article is, first, to provide the conceptual tools necessary to implement an approach based on confidence intervals, and second, to briefly demonstrate why such an approach is an interesting alternative to an approach based on NHT. As demonstrated in the article, the proposed CI approach avoids most problems related to a NHT approach and can often improve the scientific and contextual relevance of the statistical interpretations by testing range hypotheses instead of a point hypothesis and by defining the minimal value of a substantial effect. The main advantage of such a CI approach is that it replaces the notion of statistical power by an easily interpretable three-value logic (probable presence of a substantial effect, probable absence of a substantial effect and probabilistic undetermination. The demonstration includes a complete example.

  18. Contrasting Diversity Values: Statistical Inferences Based on Overlapping Confidence Intervals

    Science.gov (United States)

    MacGregor-Fors, Ian; Payton, Mark E.

    2013-01-01

    Ecologists often contrast diversity (species richness and abundances) using tests for comparing means or indices. However, many popular software applications do not support performing standard inferential statistics for estimates of species richness and/or density. In this study we simulated the behavior of asymmetric log-normal confidence intervals and determined an interval level that mimics statistical tests with P(α) = 0.05 when confidence intervals from two distributions do not overlap. Our results show that 84% confidence intervals robustly mimic 0.05 statistical tests for asymmetric confidence intervals, as has been demonstrated for symmetric ones in the past. Finally, we provide detailed user-guides for calculating 84% confidence intervals in two of the most robust and highly-used freeware related to diversity measurements for wildlife (i.e., EstimateS, Distance). PMID:23437239

  19. An approximate confidence interval for recombination fraction in ...

    African Journals Online (AJOL)

    user

    2011-02-14

    Feb 14, 2011 ... proposed a two stage Markov Chain Monte Carlo (MCMC) method to calculate an approximate confidence interval (ACI) ... Key words: Markov Chain Monte Carlo (MCMC), Gibbs sampler, approximate confidence interval, simulation size. ... from local conditional distributions at parameter valuesθ , given the ...

  20. Confidence Intervals for Effect Sizes: Applying Bootstrap Resampling

    Science.gov (United States)

    Banjanovic, Erin S.; Osborne, Jason W.

    2016-01-01

    Confidence intervals for effect sizes (CIES) provide readers with an estimate of the strength of a reported statistic as well as the relative precision of the point estimate. These statistics offer more information and context than null hypothesis statistic testing. Although confidence intervals have been recommended by scholars for many years,…

  1. A note on Nonparametric Confidence Interval for a Shift Parameter ...

    African Journals Online (AJOL)

    In this article an application of a kernel based nonparametric approach in constructing a large sample nonparametric confidence interval for a shift parameter is considered. The method is illustrated using the Cauchy distribution as a location model. The kernel-based method is found to have a shorter interval for the shift ...

  2. Confidence and coverage for Bland-Altman limits of agreement and their approximate confidence intervals.

    Science.gov (United States)

    Carkeet, Andrew; Goh, Yee Teng

    2018-05-01

    Bland and Altman described approximate methods in 1986 and 1999 for calculating confidence limits for their 95% limits of agreement, approximations which assume large subject numbers. In this paper, these approximations are compared with exact confidence intervals calculated using two-sided tolerance intervals for a normal distribution. The approximations are compared in terms of the tolerance factors themselves but also in terms of the exact confidence limits and the exact limits of agreement coverage corresponding to the approximate confidence interval methods. Using similar methods the 50th percentile of the tolerance interval are compared with the k values of 1.96 and 2, which Bland and Altman used to define limits of agreements (i.e. [Formula: see text]+/- 1.96S d and [Formula: see text]+/- 2S d ). For limits of agreement outer confidence intervals, Bland and Altman's approximations are too permissive for sample sizes confidence limits the approximations are poorer, being permissive for sample sizes of confidence intervals for 95% limits of agreements, based on two-sided tolerance factors, can be calculated easily based on tables and should be used in preference to the approximate methods, especially for small sample sizes.

  3. Confidence intervals in temperature-based death time determination.

    Science.gov (United States)

    Hubig, Michael; Muggenthaler, Holger; Mall, Gita

    2015-01-01

    Marshall and Hoare's double exponential model with Henßge's parameters is a well known method for temperature based death time estimation. The authors give 95%-confidence intervals for their method. Since body cooling is a complex thermodynamical process, one has to take into account a potential bias of the estimator. This quantity measures the systematic error of the estimators underlying model. For confidence interval radius calculation a bias of 0 is presupposed, therefore the actual probability of the true death time value to lie in the 95%-confidence interval can be much lower than 95% in case of nonvanishing bias. As in case of nonstandard conditions the confidence intervals have a probability of containing the true death time value which even in case of small corrective factor errors of Δ = ± 0.1 can be substantially smaller than the 95% claimed, the paper presents a formula for confidence intervals which keep a 95% probability in case of error Δc ⩽ ± 0.1. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  4. Estimation and interpretation of keff confidence intervals in MCNP

    International Nuclear Information System (INIS)

    Urbatsch, T.J.

    1995-11-01

    MCNP's criticality methodology and some basic statistics are reviewed. Confidence intervals are discussed, as well as how to build them and their importance in the presentation of a Monte Carlo result. The combination of MCNP's three k eff estimators is shown, theoretically and empirically, by statistical studies and examples, to be the best k eff estimator. The method of combining estimators is based on a solid theoretical foundation, namely, the Gauss-Markov Theorem in regard to the least squares method. The confidence intervals of the combined estimator are also shown to have correct coverage rates for the examples considered

  5. Confidence maps and confidence intervals for near infrared images in breast cancer.

    Science.gov (United States)

    Tosteson, T D; Pogue, B W; Demidenko, E; McBride, T O; Paulsen, K D

    1999-12-01

    This paper extends basic concepts of statistical hypothesis testing and confidence intervals to images generated by a new procedure for near infrared spectroscopic tomography being developed for use in breast cancer diagnosis. By estimating the covariance matrix of the pixels of an image from data used in the image reconstruction process, confidence maps for statistical tests on individual pixels and confidence intervals for entire images are displayed as an aid to research and clinical personnel interpreting possibly noisy images. The methods are applied to simulated and phantom-based images.

  6. Bootstrap confidence intervals for the process capability index under half-logistic distribution

    OpenAIRE

    Wararit Panichkitkosolkul

    2012-01-01

    This study concerns the construction of bootstrap confidence intervals for theprocess capability index in the case of half-logistic distribution. The bootstrap confidence intervals applied consist of standard bootstrap confidence interval, percentile bootstrap confidence interval and bias-corrected percentile bootstrap confidence interval. Using Monte Carlo simulations, the estimated coverage probabilities and average widths ofbootstrap confidence intervals are compared, with results showing ...

  7. Constructing seasonally adjusted data with time-varying confidence intervals

    NARCIS (Netherlands)

    S.J. Koopman (Siem Jan); Ph.H.B.F. Franses (Philip Hans)

    2001-01-01

    textabstractSeasonal adjustment methods transform observed time series data into estimated data, where these estimated data are constructed such that they show no or almost no seasonal variation. An advantage of model-based methods is that these can provide confidence intervals around the seasonally

  8. Parametric change point estimation, testing and confidence interval ...

    African Journals Online (AJOL)

    In many applications like finance, industry and medicine, it is important to consider that the model parameters may undergo changes at unknown moment in time. This paper deals with estimation, testing and confidence interval of a change point for a univariate variable which is assumed to be normally distributed. To detect ...

  9. A quick method to calculate QTL confidence interval

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... strap sample form the bootstrap distribution of QTL location. The 2.5 and 97.5 percentiles are lower limit and upper limit of 95% QTL confidence interval. Although bootstrap is time- demanding, especially for large complex populations, it has been used frequently. Some authors' investigation showed.

  10. Using confidence intervals for assessing reliability of real tests

    NARCIS (Netherlands)

    Oosterwijk, P.R.; van der Ark, L.A.; Sijtsma, K.

    2018-01-01

    Test authors report sample reliability values but rarely consider the sampling error and related confidence intervals. This study investigated the truth of this conjecture for 116 tests with 1,024 reliability estimates (105 pertaining to test batteries and 919 to tests measuring a single attribute)

  11. Confidence Intervals for Assessing Heterogeneity in Generalized Linear Mixed Models

    Science.gov (United States)

    Wagler, Amy E.

    2014-01-01

    Generalized linear mixed models are frequently applied to data with clustered categorical outcomes. The effect of clustering on the response is often difficult to practically assess partly because it is reported on a scale on which comparisons with regression parameters are difficult to make. This article proposes confidence intervals for…

  12. Constructing Approximate Confidence Intervals for Parameters with Structural Equation Models

    Science.gov (United States)

    Cheung, Mike W. -L.

    2009-01-01

    Confidence intervals (CIs) for parameters are usually constructed based on the estimated standard errors. These are known as Wald CIs. This article argues that likelihood-based CIs (CIs based on likelihood ratio statistics) are often preferred to Wald CIs. It shows how the likelihood-based CIs and the Wald CIs for many statistics and psychometric…

  13. Likelihood-Based Confidence Intervals in Exploratory Factor Analysis

    NARCIS (Netherlands)

    Oort, Frans J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated

  14. Likelihood-based confidence intervals in exploratory factor analysis

    NARCIS (Netherlands)

    Oort, F.J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated

  15. Likelihood-Based Confidence Intervals in Exploratory Factor Analysis

    Science.gov (United States)

    Oort, Frans J.

    2011-01-01

    In exploratory or unrestricted factor analysis, all factor loadings are free to be estimated. In oblique solutions, the correlations between common factors are free to be estimated as well. The purpose of this article is to show how likelihood-based confidence intervals can be obtained for rotated factor loadings and factor correlations, by…

  16. Quantifying uncertainty on sediment loads using bootstrap confidence intervals

    Science.gov (United States)

    Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

    2017-01-01

    Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

  17. Confidence Intervals from Realizations of Simulated Nuclear Data

    Energy Technology Data Exchange (ETDEWEB)

    Younes, W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ratkiewicz, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ressler, J. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-28

    Various statistical techniques are discussed that can be used to assign a level of confidence in the prediction of models that depend on input data with known uncertainties and correlations. The particular techniques reviewed in this paper are: 1) random realizations of the input data using Monte-Carlo methods, 2) the construction of confidence intervals to assess the reliability of model predictions, and 3) resampling techniques to impose statistical constraints on the input data based on additional information. These techniques are illustrated with a calculation of the keff value, based on the 235U(n, f) and 239Pu (n, f) cross sections.

  18. Better Confidence Intervals: The Double Bootstrap with No Pivot

    OpenAIRE

    David Letson; B.D. McCullough

    1998-01-01

    The double bootstrap is an important advance in confidence interval generation because it converges faster than the already popular single bootstrap. Yet the usual double bootstrap requires a stable pivot that is not always available, e.g., when estimating flexibilities or substitution elasticities. A recently developed double bootstrap does not require a pivot. A Monte Carlo analysis with the Waugh data finds the double bootstrap achieves nominal coverage whereas the single bootstrap does no...

  19. Comparison of Bootstrap Confidence Intervals Using Monte Carlo Simulations

    OpenAIRE

    Roberto S. Flowers-Cano; Ruperto Ortiz-Gómez; Jesús Enrique León-Jiménez; Raúl López Rivera; Luis A. Perera Cruz

    2018-01-01

    Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP), bias-corrected bootstrap (BC), accelerated bias-corrected bootstrap (BCA) and a modified version of the standard bootstrap (MSB). Different simulation scenarios were analyzed. In some cases, the mother distributi...

  20. Comparison of Bootstrap Confidence Intervals Using Monte Carlo Simulations

    Directory of Open Access Journals (Sweden)

    Roberto S. Flowers-Cano

    2018-02-01

    Full Text Available Design of hydraulic works requires the estimation of design hydrological events by statistical inference from a probability distribution. Using Monte Carlo simulations, we compared coverage of confidence intervals constructed with four bootstrap techniques: percentile bootstrap (BP, bias-corrected bootstrap (BC, accelerated bias-corrected bootstrap (BCA and a modified version of the standard bootstrap (MSB. Different simulation scenarios were analyzed. In some cases, the mother distribution function was fit to the random samples that were generated. In other cases, a distribution function different to the mother distribution was fit to the samples. When the fitted distribution had three parameters, and was the same as the mother distribution, the intervals constructed with the four techniques had acceptable coverage. However, the bootstrap techniques failed in several of the cases in which the fitted distribution had two parameters.

  1. Small Sample Confidence Intervals in Log Space Back-Transformed from Normal Space

    National Research Council Canada - National Science Library

    Tisdel, Jason E

    2006-01-01

    .... Analysis in the normal space provides point estimates and confidence intervals, but transformation back to the original space using the naive approach yields confidence intervals of impractical width...

  2. Covariate-adjusted confidence interval for the intraclass correlation coefficient.

    Science.gov (United States)

    Shoukri, Mohamed M; Donner, Allan; El-Dali, Abdelmoneim

    2013-09-01

    A crucial step in designing a new study is to estimate the required sample size. For a design involving cluster sampling, the appropriate sample size depends on the so-called design effect, which is a function of the average cluster size and the intracluster correlation coefficient (ICC). It is well-known that under the framework of hierarchical and generalized linear models, a reduction in residual error may be achieved by including risk factors as covariates. In this paper we show that the covariate design, indicating whether the covariates are measured at the cluster level or at the within-cluster subject level affects the estimation of the ICC, and hence the design effect. Therefore, the distinction between these two types of covariates should be made at the design stage. In this paper we use the nested-bootstrap method to assess the accuracy of the estimated ICC for continuous and binary response variables under different covariate structures. The codes of two SAS macros are made available by the authors for interested readers to facilitate the construction of confidence intervals for the ICC. Moreover, using Monte Carlo simulations we evaluate the relative efficiency of the estimators and evaluate the accuracy of the coverage probabilities of a 95% confidence interval on the population ICC. The methodology is illustrated using a published data set of blood pressure measurements taken on family members. © 2013. Published by Elsevier Inc. All rights reserved.

  3. GENERALISED MODEL BASED CONFIDENCE INTERVALS IN TWO STAGE CLUSTER SAMPLING

    Directory of Open Access Journals (Sweden)

    Christopher Ouma Onyango

    2010-09-01

    Full Text Available Chambers and Dorfman (2002 constructed bootstrap confidence intervals in model based estimation for finite population totals assuming that auxiliary values are available throughout a target population and that the auxiliary values are independent. They also assumed that the cluster sizes are known throughout the target population. We now extend to two stage sampling in which the cluster sizes are known only for the sampled clusters, and we therefore predict the unobserved part of the population total. Jan and Elinor (2008 have done similar work, but unlike them, we use a general model, in which the auxiliary values are not necessarily independent. We demonstrate that the asymptotic properties of our proposed estimator and its coverage rates are better than those constructed under the model assisted local polynomial regression model.

  4. Secure and Usable Bio-Passwords based on Confidence Interval

    Directory of Open Access Journals (Sweden)

    Aeyoung Kim

    2017-02-01

    Full Text Available The most popular user-authentication method is the password. Many authentication systems try to enhance their security by enforcing a strong password policy, and by using the password as the first factor, something you know, with the second factor being something you have. However, a strong password policy and a multi-factor authentication system can make it harder for a user to remember the password and login in. In this paper a bio-password-based scheme is proposed as a unique authentication method, which uses biometrics and confidence interval sets to enhance the security of the log-in process and make it easier as well. The method offers a user-friendly solution for creating and registering strong passwords without the user having to memorize them. Here we also show the results of our experiments which demonstrate the efficiency of this method and how it can be used to protect against a variety of malicious attacks.

  5. Estimation and interpretation of keff confidence intervals in MCNP

    International Nuclear Information System (INIS)

    Urbatsch, T.J.

    1995-01-01

    MCNP has three different, but correlated, estimators for Calculating k eff in nuclear criticality calculations: collision, absorption, and track length estimators. The combination of these three estimators, the three-combined k eff estimator, is shown to be the best k eff estimator available in MCNP for estimating k eff confidence intervals. Theoretically, the Gauss-Markov Theorem provides a solid foundation for MCNP's three-combined estimator. Analytically, a statistical study, where the estimates are drawn using a known covariance matrix, shows that the three-combined estimator is superior to the individual estimator with the smallest variance. The importance of MCNP's batch statistics is demonstrated by an investigation of the effects of individual estimator variance bias on the combination of estimators, both heuristically with the analytical study and emprically with MCNP

  6. The 95% confidence intervals of error rates and discriminant coefficients

    Directory of Open Access Journals (Sweden)

    Shuichi Shinmura

    2015-02-01

    Full Text Available Fisher proposed a linear discriminant function (Fisher’s LDF. From 1971, we analysed electrocardiogram (ECG data in order to develop the diagnostic logic between normal and abnormal symptoms by Fisher’s LDF and a quadratic discriminant function (QDF. Our four years research was inferior to the decision tree logic developed by the medical doctor. After this experience, we discriminated many data and found four problems of the discriminant analysis. A revised Optimal LDF by Integer Programming (Revised IP-OLDF based on the minimum number of misclassification (minimum NM criterion resolves three problems entirely [13, 18]. In this research, we discuss fourth problem of the discriminant analysis. There are no standard errors (SEs of the error rate and discriminant coefficient. We propose a k-fold crossvalidation method. This method offers a model selection technique and a 95% confidence intervals (C.I. of error rates and discriminant coefficients.

  7. Confidence Intervals for Asbestos Fiber Counts: Approximate Negative Binomial Distribution.

    Science.gov (United States)

    Bartley, David; Slaven, James; Harper, Martin

    2017-03-01

    The negative binomial distribution is adopted for analyzing asbestos fiber counts so as to account for both the sampling errors in capturing only a finite number of fibers and the inevitable human variation in identifying and counting sampled fibers. A simple approximation to this distribution is developed for the derivation of quantiles and approximate confidence limits. The success of the approximation depends critically on the use of Stirling's expansion to sufficient order, on exact normalization of the approximating distribution, on reasonable perturbation of quantities from the normal distribution, and on accurately approximating sums by inverse-trapezoidal integration. Accuracy of the approximation developed is checked through simulation and also by comparison to traditional approximate confidence intervals in the specific case that the negative binomial distribution approaches the Poisson distribution. The resulting statistics are shown to relate directly to early research into the accuracy of asbestos sampling and analysis. Uncertainty in estimating mean asbestos fiber concentrations given only a single count is derived. Decision limits (limits of detection) and detection limits are considered for controlling false-positive and false-negative detection assertions and are compared to traditional limits computed assuming normal distributions. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2017.

  8. Confidence intervals for directly standardized rates using mid-p gamma intervals.

    Science.gov (United States)

    Fay, Michael P; Kim, Sungwook

    2017-03-01

    Directly standardized rates continue to be an integral tool for presenting rates for diseases that are highly dependent on age, such as cancer. Statistically, these rates are modeled as a weighted sum of Poisson random variables. This is a difficult statistical problem, because there are k observed Poisson variables and k unknown means. The gamma confidence interval has been shown through simulations to have at least nominal coverage in all simulated scenarios, but it can be overly conservative. Previous modifications to that method have closer to nominal coverage on average, but they do not achieve the nominal coverage bound in all situations. Further, those modifications are not central intervals, and the upper coverage error rate can be substantially more than half the nominal error. Here we apply a mid-p modification to the gamma confidence interval. Typical mid-p methods forsake guaranteed coverage to get coverage that is sometimes higher and sometimes lower than the nominal coverage rate, depending on the values of the parameters. The mid-p gamma interval does not have guaranteed coverage in all situations; however, in the (not rare) situations where the gamma method is overly conservative, the mid-p gamma interval often has at least nominal coverage. The mid-p gamma interval is especially appropriate when one wants a central interval, since simulations show that in many situations both the upper and lower coverage error rates are on average less than or equal to half the nominal error rate. © Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

  9. Evaluating the performance of simultaneous stepwise confidence intervals for the difference between two Poisson rates

    OpenAIRE

    Bright, Brianna C.; Soulakova, Julia N.

    2014-01-01

    We consider the problem of simultaneously estimating Poisson rate differences via applications of the Hsu and Berger stepwise confidence interval method (termed HBM), where comparisons to a common reference group are performed. We discuss continuity-corrected confidence intervals and investigate the HBM performance with a moment-based confidence interval, and uncorrected and corrected for continuity Wald and Pooled confidence intervals. Using simulations, we compare nine individual confidence...

  10. Confidence intervals for experiments with background and small numbers of events

    International Nuclear Information System (INIS)

    Bruechle, W.

    2002-07-01

    Methods to find a confidence interval for Poisson distributed variables are illuminated, especially for the case of poor statistics. The application of 'central' and 'highest probability density' confidence intervals is compared for the case of low count-rates. A method to determine realistic estimates of the confidence intervals for Poisson distributed variables affected with background, and their ratios, is given. (orig.)

  11. Introduction to Sample Size Choice for Confidence Intervals Based on "t" Statistics

    Science.gov (United States)

    Liu, Xiaofeng Steven; Loudermilk, Brandon; Simpson, Thomas

    2014-01-01

    Sample size can be chosen to achieve a specified width in a confidence interval. The probability of obtaining a narrow width given that the confidence interval includes the population parameter is defined as the power of the confidence interval, a concept unfamiliar to many practitioners. This article shows how to utilize the Statistical Analysis…

  12. An Introduction to Confidence Intervals for Both Statistical Estimates and Effect Sizes.

    Science.gov (United States)

    Capraro, Mary Margaret

    This paper summarizes methods of estimating confidence intervals, including classical intervals and intervals for effect sizes. The recent American Psychological Association (APA) Task Force on Statistical Inference report suggested that confidence intervals should always be reported, and the fifth edition of the APA "Publication Manual"…

  13. Bootstrap confidence intervals for three-way methods

    NARCIS (Netherlands)

    Kiers, Henk A.L.

    Results from exploratory three-way analysis techniques such as CANDECOMP/PARAFAC and Tucker3 analysis are usually presented without giving insight into uncertainties due to sampling. Here a bootstrap procedure is proposed that produces percentile intervals for all output parameters. Special

  14. Using an R Shiny to Enhance the Learning Experience of Confidence Intervals

    Science.gov (United States)

    Williams, Immanuel James; Williams, Kelley Kim

    2018-01-01

    Many students find understanding confidence intervals difficult, especially because of the amalgamation of concepts such as confidence levels, standard error, point estimates and sample sizes. An R Shiny application was created to assist the learning process of confidence intervals using graphics and data from the US National Basketball…

  15. Confidence Intervals for Laboratory Sonic Boom Annoyance Tests

    Science.gov (United States)

    Rathsam, Jonathan; Christian, Andrew

    2016-01-01

    Commercial supersonic flight is currently forbidden over land because sonic booms have historically caused unacceptable annoyance levels in overflown communities. NASA is providing data and expertise to noise regulators as they consider relaxing the ban for future quiet supersonic aircraft. One deliverable NASA will provide is a predictive model for indoor annoyance to aid in setting an acceptable quiet sonic boom threshold. A laboratory study was conducted to determine how indoor vibrations caused by sonic booms affect annoyance judgments. The test method required finding the point of subjective equality (PSE) between sonic boom signals that cause vibrations and signals not causing vibrations played at various amplitudes. This presentation focuses on a few statistical techniques for estimating the interval around the PSE. The techniques examined are the Delta Method, Parametric and Nonparametric Bootstrapping, and Bayesian Posterior Estimation.

  16. Graphing within-subjects confidence intervals using SPSS and S-Plus.

    Science.gov (United States)

    Wright, Daniel B

    2007-02-01

    Within-subjects confidence intervals are often appropriate to report and to display. Loftus and Masson (1994) have reported methods to calculate these, and their use is becoming common. In the present article, procedures for calculating within-subjects confidence intervals in SPSS and S-Plus are presented (an R version is on the accompanying Web site). The procedure in S-Plus allows the user to report the bias corrected and adjusted bootstrap confidence intervals as well as the standard confidence intervals based on traditional methods. The presented code can be easily altered to fit the individual user's needs.

  17. The P Value Problem in Otolaryngology: Shifting to Effect Sizes and Confidence Intervals.

    Science.gov (United States)

    Vila, Peter M; Townsend, Melanie Elizabeth; Bhatt, Neel K; Kao, W Katherine; Sinha, Parul; Neely, J Gail

    2017-06-01

    There is a lack of reporting effect sizes and confidence intervals in the current biomedical literature. The objective of this article is to present a discussion of the recent paradigm shift encouraging the use of reporting effect sizes and confidence intervals. Although P values help to inform us about whether an effect exists due to chance, effect sizes inform us about the magnitude of the effect (clinical significance), and confidence intervals inform us about the range of plausible estimates for the general population mean (precision). Reporting effect sizes and confidence intervals is a necessary addition to the biomedical literature, and these concepts are reviewed in this article.

  18. Confidence Interval Based Parameter Estimation—A New SOCR Applet and Activity

    Science.gov (United States)

    Christou, Nicolas; Dinov, Ivo D.

    2011-01-01

    Many scientific investigations depend on obtaining data-driven, accurate, robust and computationally-tractable parameter estimates. In the face of unavoidable intrinsic variability, there are different algorithmic approaches, prior assumptions and fundamental principles for computing point and interval estimates. Efficient and reliable parameter estimation is critical in making inference about observable experiments, summarizing process characteristics and prediction of experimental behaviors. In this manuscript, we demonstrate simulation, construction, validation and interpretation of confidence intervals, under various assumptions, using the interactive web-based tools provided by the Statistics Online Computational Resource (http://www.SOCR.ucla.edu). Specifically, we present confidence interval examples for population means, with known or unknown population standard deviation; population variance; population proportion (exact and approximate), as well as confidence intervals based on bootstrapping or the asymptotic properties of the maximum likelihood estimates. Like all SOCR resources, these confidence interval resources may be openly accessed via an Internet-connected Java-enabled browser. The SOCR confidence interval applet enables the user to empirically explore and investigate the effects of the confidence-level, the sample-size and parameter of interest on the corresponding confidence interval. Two applications of the new interval estimation computational library are presented. The first one is a simulation of confidence interval estimating the US unemployment rate and the second application demonstrates the computations of point and interval estimates of hippocampal surface complexity for Alzheimers disease patients, mild cognitive impairment subjects and asymptomatic controls. PMID:21655319

  19. Confidence interval based parameter estimation--a new SOCR applet and activity.

    Directory of Open Access Journals (Sweden)

    Nicolas Christou

    Full Text Available Many scientific investigations depend on obtaining data-driven, accurate, robust and computationally-tractable parameter estimates. In the face of unavoidable intrinsic variability, there are different algorithmic approaches, prior assumptions and fundamental principles for computing point and interval estimates. Efficient and reliable parameter estimation is critical in making inference about observable experiments, summarizing process characteristics and prediction of experimental behaviors. In this manuscript, we demonstrate simulation, construction, validation and interpretation of confidence intervals, under various assumptions, using the interactive web-based tools provided by the Statistics Online Computational Resource (http://www.SOCR.ucla.edu. Specifically, we present confidence interval examples for population means, with known or unknown population standard deviation; population variance; population proportion (exact and approximate, as well as confidence intervals based on bootstrapping or the asymptotic properties of the maximum likelihood estimates. Like all SOCR resources, these confidence interval resources may be openly accessed via an Internet-connected Java-enabled browser. The SOCR confidence interval applet enables the user to empirically explore and investigate the effects of the confidence-level, the sample-size and parameter of interest on the corresponding confidence interval. Two applications of the new interval estimation computational library are presented. The first one is a simulation of confidence interval estimating the US unemployment rate and the second application demonstrates the computations of point and interval estimates of hippocampal surface complexity for Alzheimers disease patients, mild cognitive impairment subjects and asymptomatic controls.

  20. Bootstrap Confidence Intervals for Ordinary Least Squares Factor Loadings and Correlations in Exploratory Factor Analysis

    Science.gov (United States)

    Zhang, Guangjian; Preacher, Kristopher J.; Luo, Shanhong

    2010-01-01

    This article is concerned with using the bootstrap to assign confidence intervals for rotated factor loadings and factor correlations in ordinary least squares exploratory factor analysis. Coverage performances of "SE"-based intervals, percentile intervals, bias-corrected percentile intervals, bias-corrected accelerated percentile…

  1. Confidence Intervals for the Mean: To Bootstrap or Not to Bootstrap

    Science.gov (United States)

    Calzada, Maria E.; Gardner, Holly

    2011-01-01

    The results of a simulation conducted by a research team involving undergraduate and high school students indicate that when data is symmetric the student's "t" confidence interval for a mean is superior to the studied non-parametric bootstrap confidence intervals. When data is skewed and for sample sizes n greater than or equal to 10,…

  2. Applying Bootstrap Resampling to Compute Confidence Intervals for Various Statistics with R

    Science.gov (United States)

    Dogan, C. Deha

    2017-01-01

    Background: Most of the studies in academic journals use p values to represent statistical significance. However, this is not a good indicator of practical significance. Although confidence intervals provide information about the precision of point estimation, they are, unfortunately, rarely used. The infrequent use of confidence intervals might…

  3. P values and confidence intervals are reported in almost all scientific ...

    African Journals Online (AJOL)

    and there are no significant results. This article describes some facts about the p value and confidence intervals. The reporting of p values and confidence intervals usually follows hypothesis testing or significance testing. Most scientific investigations involve the testing of hypotheses. These are formal procedures for testing.

  4. A Comparison of Methods for Estimating Confidence Intervals for Omega-Squared Effect Size

    Science.gov (United States)

    Finch, W. Holmes; French, Brian F.

    2012-01-01

    Effect size use has been increasing in the past decade in many research areas. Confidence intervals associated with effect sizes are encouraged to be reported. Prior work has investigated the performance of confidence interval estimation with Cohen's d. This study extends this line of work to the analysis of variance case with more than two…

  5. Improved Confidence Intervals of a Small Probability From Pooled Testing With Misclassification

    Directory of Open Access Journals (Sweden)

    Chunling eLiu

    2013-10-01

    Full Text Available This article concerns construction of confidence intervals of theprevalence of a rare disease using Dorfman's pooled testingprocedure when the disease status is classified with an imperfectbiomarker. Such an interval can be derived by converting aconfidence interval of the probability that a group is testedpositive. The Wald confidence intervals based on normalapproximation are shown to be inefficient in terms of coverageprobability, even for relatively large number of pools. A fewalternatives are proposed and their performance is investigated interms of coverage probability and length of intervals.

  6. Confidence intervals for proportion difference from two independent partially validated series.

    Science.gov (United States)

    Qiu, Shi-Fang; Poon, Wai-Yin; Tang, Man-Lai

    2016-10-01

    Partially validated series are common when a gold-standard test is too expensive to be applied to all subjects, and hence a fallible device is used accordingly to measure the presence of a characteristic of interest. In this article, confidence interval construction for proportion difference between two independent partially validated series is studied. Ten confidence intervals based on the method of variance estimates recovery (MOVER) are proposed, with each using the confidence limits for the two independent binomial proportions obtained by the asymptotic, Logit-transformation, Agresti-Coull and Bayesian methods. The performances of the proposed confidence intervals and three likelihood-based intervals available in the literature are compared with respect to the empirical coverage probability, confidence width and ratio of mesial non-coverage to non-coverage probability. Our empirical results show that (1) all confidence intervals exhibit good performance in large samples; (2) confidence intervals based on MOVER combining the confidence limits for binomial proportions based on Wilson, Agresti-Coull, Logit-transformation, Bayesian (with three priors) methods perform satisfactorily from small to large samples, and hence can be recommended for practical applications. Two real data sets are analysed to illustrate the proposed methods. © The Author(s) 2014.

  7. Teach a Confidence Interval for the Median in the First Statistics Course

    Science.gov (United States)

    Howington, Eric B.

    2017-01-01

    Few introductory statistics courses consider statistical inference for the median. This article argues in favour of adding a confidence interval for the median to the first statistics course. Several methods suitable for introductory statistics students are identified and briefly reviewed.

  8. Evaluation of Jackknife and Bootstrap for Defining Confidence Intervals for Pairwise Agreement Measures

    Science.gov (United States)

    Severiano, Ana; Carriço, João A.; Robinson, D. Ashley; Ramirez, Mário; Pinto, Francisco R.

    2011-01-01

    Several research fields frequently deal with the analysis of diverse classification results of the same entities. This should imply an objective detection of overlaps and divergences between the formed clusters. The congruence between classifications can be quantified by clustering agreement measures, including pairwise agreement measures. Several measures have been proposed and the importance of obtaining confidence intervals for the point estimate in the comparison of these measures has been highlighted. A broad range of methods can be used for the estimation of confidence intervals. However, evidence is lacking about what are the appropriate methods for the calculation of confidence intervals for most clustering agreement measures. Here we evaluate the resampling techniques of bootstrap and jackknife for the calculation of the confidence intervals for clustering agreement measures. Contrary to what has been shown for some statistics, simulations showed that the jackknife performs better than the bootstrap at accurately estimating confidence intervals for pairwise agreement measures, especially when the agreement between partitions is low. The coverage of the jackknife confidence interval is robust to changes in cluster number and cluster size distribution. PMID:21611165

  9. Confidence Intervals for Weighted Composite Scores under the Compound Binomial Error Model

    Science.gov (United States)

    Kim, Kyung Yong; Lee, Won-Chan

    2018-01-01

    Reporting confidence intervals with test scores helps test users make important decisions about examinees by providing information about the precision of test scores. Although a variety of estimation procedures based on the binomial error model are available for computing intervals for test scores, these procedures assume that items are randomly…

  10. Confidence Intervals for True Scores Using the Skew-Normal Distribution

    Science.gov (United States)

    Garcia-Perez, Miguel A.

    2010-01-01

    A recent comparative analysis of alternative interval estimation approaches and procedures has shown that confidence intervals (CIs) for true raw scores determined with the Score method--which uses the normal approximation to the binomial distribution--have actual coverage probabilities that are closest to their nominal level. It has also recently…

  11. Binomial confidence intervals for testing non-inferiority or superiority: a practitioner's dilemma.

    Science.gov (United States)

    Pradhan, Vivek; Evans, John C; Banerjee, Tathagata

    2016-08-01

    In testing for non-inferiority or superiority in a single arm study, the confidence interval of a single binomial proportion is frequently used. A number of such intervals are proposed in the literature and implemented in standard software packages. Unfortunately, use of different intervals leads to conflicting conclusions. Practitioners thus face a serious dilemma in deciding which one to depend on. Is there a way to resolve this dilemma? We address this question by investigating the performances of ten commonly used intervals of a single binomial proportion, in the light of two criteria, viz., coverage and expected length of the interval. © The Author(s) 2013.

  12. Binomial Distribution Sample Confidence Intervals Estimation 1. Sampling and Medical Key Parameters Calculation

    Directory of Open Access Journals (Sweden)

    Tudor DRUGAN

    2003-08-01

    Full Text Available The aim of the paper was to present the usefulness of the binomial distribution in studying of the contingency tables and the problems of approximation to normality of binomial distribution (the limits, advantages, and disadvantages. The classification of the medical keys parameters reported in medical literature and expressing them using the contingency table units based on their mathematical expressions restrict the discussion of the confidence intervals from 34 parameters to 9 mathematical expressions. The problem of obtaining different information starting with the computed confidence interval for a specified method, information like confidence intervals boundaries, percentages of the experimental errors, the standard deviation of the experimental errors and the deviation relative to significance level was solves through implementation in PHP programming language of original algorithms. The cases of expression, which contain two binomial variables, were separately treated. An original method of computing the confidence interval for the case of two-variable expression was proposed and implemented. The graphical representation of the expression of two binomial variables for which the variation domain of one of the variable depend on the other variable was a real problem because the most of the software used interpolation in graphical representation and the surface maps were quadratic instead of triangular. Based on an original algorithm, a module was implements in PHP in order to represent graphically the triangular surface plots. All the implementation described above was uses in computing the confidence intervals and estimating their performance for binomial distributions sample sizes and variable.

  13. Tests and Confidence Intervals for an Extended Variance Component Using the Modified Likelihood Ratio Statistic

    DEFF Research Database (Denmark)

    Christensen, Ole Fredslund; Frydenberg, Morten; Jensen, Jens Ledet

    2005-01-01

    The large deviation modified likelihood ratio statistic is studied for testing a variance component equal to a specified value. Formulas are presented in the general balanced case, whereas in the unbalanced case only the one-way random effects model is studied. Simulation studies are presented......, showing that the normal approximation to the large deviation modified likelihood ratio statistic gives confidence intervals for variance components with coverage probabilities very close to the nominal confidence coefficient....

  14. Calculation of the confidence intervals for transformation parameters in the registration of medical images.

    Science.gov (United States)

    Bansal, Ravi; Staib, Lawrence H; Laine, Andrew F; Xu, Dongrong; Liu, Jun; Posecion, Lainie F; Peterson, Bradley S

    2009-04-01

    Images from different individuals typically cannot be registered precisely because anatomical features within the images differ across the people imaged and because the current methods for image registration have inherent technological limitations that interfere with perfect registration. Quantifying the inevitable error in image registration is therefore of crucial importance in assessing the effects that image misregistration may have on subsequent analyses in an imaging study. We have developed a mathematical framework for quantifying errors in registration by computing the confidence intervals of the estimated parameters (3 translations, 3 rotations, and 1 global scale) for the similarity transformation. The presence of noise in images and the variability in anatomy across individuals ensures that estimated registration parameters are always random variables. We assume a functional relation among intensities across voxels in the images, and we use the theory of nonlinear, least-squares estimation to show that the parameters are multivariate Gaussian distributed. We then use the covariance matrix of this distribution to compute the confidence intervals of the transformation parameters. These confidence intervals provide a quantitative assessment of the registration error across the images. Because transformation parameters are nonlinearly related to the coordinates of landmark points in the brain, we subsequently show that the coordinates of those landmark points are also multivariate Gaussian distributed. Using these distributions, we then compute the confidence intervals of the coordinates for landmark points in the image. Each of these confidence intervals in turn provides a quantitative assessment of the registration error at a particular landmark point. Because our method is computationally intensive, however, its current implementation is limited to assessing the error of the parameters in the similarity transformation across images. We assessed the

  15. Exact confidence intervals for channelized Hotelling observer performance in image quality studies.

    Science.gov (United States)

    Wunderlich, Adam; Noo, Frederic; Gallas, Brandon D; Heilbrun, Marta E

    2015-02-01

    Task-based assessments of image quality constitute a rigorous, principled approach to the evaluation of imaging system performance. To conduct such assessments, it has been recognized that mathematical model observers are very useful, particularly for purposes of imaging system development and optimization. One type of model observer that has been widely applied in the medical imaging community is the channelized Hotelling observer (CHO), which is well-suited to known-location discrimination tasks. In the present work, we address the need for reliable confidence interval estimators of CHO performance. Specifically, we show that the bias associated with point estimates of CHO performance can be overcome by using confidence intervals proposed by Reiser for the Mahalanobis distance. In addition, we find that these intervals are well-defined with theoretically-exact coverage probabilities, which is a new result not proved by Reiser. The confidence intervals are tested with Monte Carlo simulation and demonstrated with two examples comparing X-ray CT reconstruction strategies. Moreover, commonly-used training/testing approaches are discussed and compared to the exact confidence intervals. MATLAB software implementing the estimators described in this work is publicly available at http://code.google.com/p/iqmodelo/.

  16. The Optimal Confidence Intervals for Agricultural Products’ Price Forecasts Based on Hierarchical Historical Errors

    Directory of Open Access Journals (Sweden)

    Yi Wang

    2016-12-01

    Full Text Available With the levels of confidence and system complexity, interval forecasts and entropy analysis can deliver more information than point forecasts. In this paper, we take receivers’ demands as our starting point, use the trade-off model between accuracy and informativeness as the criterion to construct the optimal confidence interval, derive the theoretical formula of the optimal confidence interval and propose a practical and efficient algorithm based on entropy theory and complexity theory. In order to improve the estimation precision of the error distribution, the point prediction errors are STRATIFIED according to prices and the complexity of the system; the corresponding prediction error samples are obtained by the prices stratification; and the error distributions are estimated by the kernel function method and the stability of the system. In a stable and orderly environment for price forecasting, we obtain point prediction error samples by the weighted local region and RBF (Radial basis function neural network methods, forecast the intervals of the soybean meal and non-GMO (Genetically Modified Organism soybean continuous futures closing prices and implement unconditional coverage, independence and conditional coverage tests for the simulation results. The empirical results are compared from various interval evaluation indicators, different levels of noise, several target confidence levels and different point prediction methods. The analysis shows that the optimal interval construction method is better than the equal probability method and the shortest interval method and has good anti-noise ability with the reduction of system entropy; the hierarchical estimation error method can obtain higher accuracy and better interval estimation than the non-hierarchical method in a stable system.

  17. Binomial Distribution Sample Confidence Intervals Estimation 7. Absolute Risk Reduction and ARR-like Expressions

    Directory of Open Access Journals (Sweden)

    Andrei ACHIMAŞ CADARIU

    2004-08-01

    Full Text Available Assessments of a controlled clinical trial suppose to interpret some key parameters as the controlled event rate, experimental event date, relative risk, absolute risk reduction, relative risk reduction, number needed to treat when the effect of the treatment are dichotomous variables. Defined as the difference in the event rate between treatment and control groups, the absolute risk reduction is the parameter that allowed computing the number needed to treat. The absolute risk reduction is compute when the experimental treatment reduces the risk for an undesirable outcome/event. In medical literature when the absolute risk reduction is report with its confidence intervals, the method used is the asymptotic one, even if it is well know that may be inadequate. The aim of this paper is to introduce and assess nine methods of computing confidence intervals for absolute risk reduction and absolute risk reduction – like function.Computer implementations of the methods use the PHP language. Methods comparison uses the experimental errors, the standard deviations, and the deviation relative to the imposed significance level for specified sample sizes. Six methods of computing confidence intervals for absolute risk reduction and absolute risk reduction-like functions were assessed using random binomial variables and random sample sizes.The experiments shows that the ADAC, and ADAC1 methods obtains the best overall performance of computing confidence intervals for absolute risk reduction.

  18. Optimal and Most Exact Confidence Intervals for Person Parameters in Item Response Theory Models

    Science.gov (United States)

    Doebler, Anna; Doebler, Philipp; Holling, Heinz

    2013-01-01

    The common way to calculate confidence intervals for item response theory models is to assume that the standardized maximum likelihood estimator for the person parameter [theta] is normally distributed. However, this approximation is often inadequate for short and medium test lengths. As a result, the coverage probabilities fall below the given…

  19. Evolution of heterogeneity (I2) estimates and their 95% confidence intervals in large meta-analyses

    DEFF Research Database (Denmark)

    Thorlund, Kristian; Imberger, Georgina; Johnston, Bradley C

    2012-01-01

    by sampling error. Recent studies have raised concerns about the reliability of I(2) estimates, due to their dependence on the precision of included trials and time-dependent biases. Authors have also advocated use of 95% confidence intervals (CIs) to express the uncertainty associated with I(2) estimates...

  20. WASP (Write a Scientific Paper) using Excel - 6: Standard error and confidence interval.

    Science.gov (United States)

    Grech, Victor

    2018-02-03

    The calculation of descriptive statistics includes the calculation of standard error and confidence interval, an inevitable component of data analysis in inferential statistics. This paper provides pointers as to how to do this in Microsoft Excel™. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. Confidence intervals around Bayes Cost in multi-state diagnostic settings to estimate optimal performance.

    Science.gov (United States)

    Batterton, Katherine A; Schubert, Christine M

    2014-08-30

    A critical feature of diagnostic testing is correctly classifying subjects based upon specified thresholds of some measure. The commonly employed Youden index determines a test's optimal thresholds by maximizing the correct classification rates for a diagnostic scenario. An alternative to the Youden index is the cost function, Bayes Cost (BC). BC determines a test's optimal setting by minimizing the sum of all misclassification rates from the test. Unlike the Youden index, BC can consider a priori costs of all the diagnostic outcomes including class specific misclassifications regardless of the number of classes. Delta method approximate confidence intervals around BC are derived under the assumption of normally distributed classes as a means for quantifying a test's performance and comparing classifiers at their optimal settings in a multi-state diagnostic framework. A simulation study is conducted to demonstrate the performance of the derived confidence intervals that are found to perform well, especially for sample sizes of 50 or larger in each diagnostic class. Finally, the proposed methods are applied to a four-class breast tissue classification problem, where four possible discriminatory features are compared under varying decision cost structures. Using the confidence intervals around BC, the best feature for classification is selected, and the optimal thresholds and their 95% confidence intervals are determined. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  2. Assessing Conformance with Benford's Law: Goodness-Of-Fit Tests and Simultaneous Confidence Intervals.

    Directory of Open Access Journals (Sweden)

    M Lesperance

    Full Text Available Benford's Law is a probability distribution for the first significant digits of numbers, for example, the first significant digits of the numbers 871 and 0.22 are 8 and 2 respectively. The law is particularly remarkable because many types of data are considered to be consistent with Benford's Law and scientists and investigators have applied it in diverse areas, for example, diagnostic tests for mathematical models in Biology, Genomics, Neuroscience, image analysis and fraud detection. In this article we present and compare statistically sound methods for assessing conformance of data with Benford's Law, including discrete versions of Cramér-von Mises (CvM statistical tests and simultaneous confidence intervals. We demonstrate that the common use of many binomial confidence intervals leads to rejection of Benford too often for truly Benford data. Based on our investigation, we recommend that the CvM statistic Ud(2, Pearson's chi-square statistic and 100(1 - α% Goodman's simultaneous confidence intervals be computed when assessing conformance with Benford's Law. Visual inspection of the data with simultaneous confidence intervals is useful for understanding departures from Benford and the influence of sample size.

  3. Multivariate Effect Size Estimation: Confidence Interval Construction via Latent Variable Modeling

    Science.gov (United States)

    Raykov, Tenko; Marcoulides, George A.

    2010-01-01

    A latent variable modeling method is outlined for constructing a confidence interval (CI) of a popular multivariate effect size measure. The procedure uses the conventional multivariate analysis of variance (MANOVA) setup and is applicable with large samples. The approach provides a population range of plausible values for the proportion of…

  4. The Distribution of the Product Explains Normal Theory Mediation Confidence Interval Estimation.

    Science.gov (United States)

    Kisbu-Sakarya, Yasemin; MacKinnon, David P; Miočević, Milica

    2014-05-01

    The distribution of the product has several useful applications. One of these applications is its use to form confidence intervals for the indirect effect as the product of 2 regression coefficients. The purpose of this article is to investigate how the moments of the distribution of the product explain normal theory mediation confidence interval coverage and imbalance. Values of the critical ratio for each random variable are used to demonstrate how the moments of the distribution of the product change across values of the critical ratio observed in research studies. Results of the simulation study showed that as skewness in absolute value increases, coverage decreases. And as skewness in absolute value and kurtosis increases, imbalance increases. The difference between testing the significance of the indirect effect using the normal theory versus the asymmetric distribution of the product is further illustrated with a real data example. This article is the first study to show the direct link between the distribution of the product and indirect effect confidence intervals and clarifies the results of previous simulation studies by showing why normal theory confidence intervals for indirect effects are often less accurate than those obtained from the asymmetric distribution of the product or from resampling methods.

  5. Methods for confidence interval estimation of a ratio parameter with application to location quotients

    Directory of Open Access Journals (Sweden)

    Beyene Joseph

    2005-10-01

    Full Text Available Abstract Background The location quotient (LQ ratio, a measure designed to quantify and benchmark the degree of relative concentration of an activity in the analysis of area localization, has received considerable attention in the geographic and economics literature. This index can also naturally be applied in the context of population health to quantify and compare health outcomes across spatial domains. However, one commonly observed limitation of LQ is its widespread use as only a point estimate without an accompanying confidence interval. Methods In this paper we present statistical methods that can be used to construct confidence intervals for location quotients. The delta and Fieller's methods are generic approaches for a ratio parameter and the generalized linear modelling framework is a useful re-parameterization particularly helpful for generating profile-likelihood based confidence intervals for the location quotient. A simulation experiment is carried out to assess the performance of each of the analytic approaches and a health utilization data set is used for illustration. Results Both the simulation results as well as the findings from the empirical data show that the different analytical methods produce very similar confidence limits for location quotients. When incidence of outcome is not rare and sample sizes are large, the confidence limits are almost indistinguishable. The confidence limits from the generalized linear model approach might be preferable in small sample situations. Conclusion LQ is a useful measure which allows quantification and comparison of health and other outcomes across defined geographical regions. It is a very simple index to compute and has a straightforward interpretation. Reporting this estimate with appropriate confidence limits using methods presented in this paper will make the measure particularly attractive for policy and decision makers.

  6. Reducing the width of confidence intervals for the difference between two population means by inverting adaptive tests.

    Science.gov (United States)

    O'Gorman, Thomas W

    2018-05-01

    In the last decade, it has been shown that an adaptive testing method could be used, along with the Robbins-Monro search procedure, to obtain confidence intervals that are often narrower than traditional confidence intervals. However, these confidence interval limits require a great deal of computation and some familiarity with stochastic search methods. We propose a method for estimating the limits of confidence intervals that uses only a few tests of significance. We compare these limits to those obtained by a lengthy Robbins-Monro stochastic search and find that the proposed method is nearly as accurate as the Robbins-Monro search. Adaptive confidence intervals that are produced by the proposed method are often narrower than traditional confidence intervals when the distributions are long-tailed, skewed, or bimodal. Moreover, the proposed method of estimating confidence interval limits is easy to understand, because it is based solely on the p-values from a few tests of significance.

  7. Hierarchical models in ecology: confidence intervals, hypothesis testing, and model selection using data cloning.

    Science.gov (United States)

    Ponciano, José Miguel; Taper, Mark L; Dennis, Brian; Lele, Subhash R

    2009-02-01

    Hierarchical statistical models are increasingly being used to describe complex ecological processes. The data cloning (DC) method is a new general technique that uses Markov chain Monte Carlo (MCMC) algorithms to compute maximum likelihood (ML) estimates along with their asymptotic variance estimates for hierarchical models. Despite its generality, the method has two inferential limitations. First, it only provides Wald-type confidence intervals, known to be inaccurate in small samples. Second, it only yields ML parameter estimates, but not the maximized likelihood values used for profile likelihood intervals, likelihood ratio hypothesis tests, and information-theoretic model selection. Here we describe how to overcome these inferential limitations with a computationally efficient method for calculating likelihood ratios via data cloning. The ability to calculate likelihood ratios allows one to do hypothesis tests, construct accurate confidence intervals and undertake information-based model selection with hierarchical models in a frequentist context. To demonstrate the use of these tools with complex ecological models, we reanalyze part of Gause's classic Paramecium data with state-space population models containing both environmental noise and sampling error. The analysis results include improved confidence intervals for parameters, a hypothesis test of laboratory replication, and a comparison of the Beverton-Holt and the Ricker growth forms based on a model selection index.

  8. Confidence intervals for a difference between lognormal means in cluster randomization trials.

    Science.gov (United States)

    Poirier, Julia; Zou, G Y; Koval, John

    2017-04-01

    Cluster randomization trials, in which intact social units are randomized to different interventions, have become popular in the last 25 years. Outcomes from these trials in many cases are positively skewed, following approximately lognormal distributions. When inference is focused on the difference between treatment arm arithmetic means, existent confidence interval procedures either make restricting assumptions or are complex to implement. We approach this problem by assuming log-transformed outcomes from each treatment arm follow a one-way random effects model. The treatment arm means are functions of multiple parameters for which separate confidence intervals are readily available, suggesting that the method of variance estimates recovery may be applied to obtain closed-form confidence intervals. A simulation study showed that this simple approach performs well in small sample sizes in terms of empirical coverage, relatively balanced tail errors, and interval widths as compared to existing methods. The methods are illustrated using data arising from a cluster randomization trial investigating a critical pathway for the treatment of community acquired pneumonia.

  9. Confidence interval construction for the difference between two correlated proportions with missing observations.

    Science.gov (United States)

    Tang, Nian-Sheng; Li, Hui-Qiong; Tang, Man-Lai; Li, Jie

    2016-01-01

    Under the assumption of missing at random, eight confidence intervals (CIs) for the difference between two correlated proportions in the presence of incomplete paired binary data are constructed on the basis of the likelihood ratio statistic, the score statistic, the Wald-type statistic, the hybrid method incorporated with the Wilson score and Agresti-Coull (AC) intervals, and the Bootstrap-resampling method. Extensive simulation studies are conducted to evaluate the performance of the presented CIs in terms of coverage probability and expected interval width. Our empirical results evidence that the Wilson-score-based hybrid CI and the Wald-type CI together with the constrained maximum likelihood estimates perform well for small-to-moderate sample sizes in the sense that (i) their empirical coverage probabilities are quite close to the prespecified confidence level, (ii) their expected interval widths are shorter, and (iii) their ratios of the mesial non-coverage to non-coverage probabilities lie in interval [0.4, 0.6]. An example from a neurological study is used to illustrate the proposed methodologies.

  10. A better confidence interval for the sensitivity at a fixed level of specificity for diagnostic tests with continuous endpoints.

    Science.gov (United States)

    Shan, Guogen

    2017-02-01

    For a diagnostic test with continuous measurement, it is often important to construct confidence intervals for the sensitivity at a fixed level of specificity. Bootstrap-based confidence intervals were shown to have good performance as compared to others, and the one by Zhou and Qin (2005) was recommended as the best existing confidence interval, named the BTII interval. We propose two new confidence intervals based on the profile variance method and conduct extensive simulation studies to compare the proposed intervals and the BTII intervals under a wide range of conditions. An example from a medical study on severe head trauma is used to illustrate application of the new intervals. The new proposed intervals generally have better performance than the BTII interval.

  11. Confidence Intervals Verification for Simulated Error Rate Performance of Wireless Communication System

    KAUST Repository

    Smadi, Mahmoud A.

    2012-12-06

    In this paper, we derived an efficient simulation method to evaluate the error rate of wireless communication system. Coherent binary phase-shift keying system is considered with imperfect channel phase recovery. The results presented demonstrate the system performance under very realistic Nakagami-m fading and additive white Gaussian noise channel. On the other hand, the accuracy of the obtained results is verified through running the simulation under a good confidence interval reliability of 95 %. We see that as the number of simulation runs N increases, the simulated error rate becomes closer to the actual one and the confidence interval difference reduces. Hence our results are expected to be of significant practical use for such scenarios. © 2012 Springer Science+Business Media New York.

  12. Energy Performance Certificate of building and confidence interval in assessment: An Italian case study

    International Nuclear Information System (INIS)

    Tronchin, Lamberto; Fabbri, Kristian

    2012-01-01

    The Directive 2002/91/CE introduced the Energy Performance Certificate (EPC), an energy policy tool. The aim of the EPC is to inform building buyers about the energy performance and energy costs of buildings. The EPCs represent a specific energy policy tool to orient the building sector and real-estate markets toward higher energy efficiency buildings. The effectiveness of the EPC depends on two factors: •The accuracy of energy performance evaluation made by independent experts. •The capability of the energy classification and of the scale of energy performance to control the energy index fluctuations. In this paper, the results of a case study located in Italy are shown. In this example, 162 independent technicians on energy performance of building evaluation have studied the same building. The results reveal which part of confidence intervals is dependent on software misunderstanding and that the energy classification ranges are able to tolerate the fluctuation of energy indices. The example was chosen in accordance with the legislation of the Emilia-Romagna Region on Energy Efficiency of Buildings. Following these results, some thermo-economic evaluation related to building and energy labelling are illustrated, as the EPC, which is an energy policy tool for the real-estate market and building sector to find a way to build or retrofit an energy efficiency building. - Highlights: ► Evaluation of the accuracy of energy performance of buildings in relation with the knowledge of independent experts. ► Round robin test based on 162 case studies on the confidence intervals expressed by independent experts. ► Statistical considerations between the confidence intervals expressed by independent experts and energy simulation software. ► Relation between “proper class” in energy classification of buildings and confidence intervals of independent experts.

  13. Growth Estimators and Confidence Intervals for the Mean of Negative Binomial Random Variables with Unknown Dispersion

    Directory of Open Access Journals (Sweden)

    David Shilane

    2013-01-01

    Full Text Available The negative binomial distribution becomes highly skewed under extreme dispersion. Even at moderately large sample sizes, the sample mean exhibits a heavy right tail. The standard normal approximation often does not provide adequate inferences about the data's expected value in this setting. In previous work, we have examined alternative methods of generating confidence intervals for the expected value. These methods were based upon Gamma and Chi Square approximations or tail probability bounds such as Bernstein's inequality. We now propose growth estimators of the negative binomial mean. Under high dispersion, zero values are likely to be overrepresented in the data. A growth estimator constructs a normal-style confidence interval by effectively removing a small, predetermined number of zeros from the data. We propose growth estimators based upon multiplicative adjustments of the sample mean and direct removal of zeros from the sample. These methods do not require estimating the nuisance dispersion parameter. We will demonstrate that the growth estimators' confidence intervals provide improved coverage over a wide range of parameter values and asymptotically converge to the sample mean. Interestingly, the proposed methods succeed despite adding both bias and variance to the normal approximation.

  14. Confidence intervals for the ratio of two median residual lifetimes with left-truncated and right-censored data.

    Science.gov (United States)

    Tsai, Tsung-Hsien; Tsai, Wei-Yann; Chi, Yunchan; Chang, Sheng-Mao

    2016-03-01

    The confidence intervals for the ratio of two median residual lifetimes are developed for left-truncated and right-censored data. The approach of Su and Wei (1993) is first extended by replacing the Kaplan-Meier survival estimator with the estimator of the conditional survival function (Lynden-Bell, 1971). This procedure does not involve a nonparametric estimation of the probability density function of the failure time. However, the Su and Wei type confidence intervals are very conservative even for larger sample size. Therefore, this article proposes an alternative confidence interval for the ratio of two median residual lifetimes, which is not only without nonparametric estimation of the density function of failure times but is also computationally simpler than the Su and Wei type confidence interval. A simulation study is conducted to examine the accuracy of these confidence intervals and the implementation of these confidence intervals to two real data sets is illustrated. © 2015, The International Biometric Society.

  15. Study of coverage of confidence intervals for the standardized mortality ratio in studies with missing death certificates.

    Science.gov (United States)

    Timkova, Jana; Kotik, Lukas; Tomasek, Ladislav

    2017-11-30

    This paper assesses the coverage probability of commonly used confidence intervals for the standardized mortality ratio (SMR) when death certificates are missing. It also proposes alternative confidence interval approaches with coverage probabilities close to .95. In epidemiology, the SMR is an important measure of risk of disease mortality (or incidence) to compare a specific group to a reference population. The appropriate confidence interval for the SMR is crucial, especially when the SMR is close to 1.0 and the statistical significance of the risk needs to be determined. There are several ways to calculate confidence intervals, depending on a study characteristics (ie, studies with small number of deaths, studies with small counts, aggregate SMRs based on several countries or time periods, and studies with missing death certificates). This paper summarizes the most commonly used confidence intervals and newly applies several existing approaches not previously used for SMR confidence intervals. The coverage probability and length of the different confidence intervals are assessed using a simulation study and different scenarios. The performance of the confidence intervals for the lung cancer SMR and all other cancer SMR is also assessed using the dataset of French and Czech uranium miners. Finally, the most appropriate confidence intervals to use under different study scenarios are recommended. Copyright © 2017 John Wiley & Sons, Ltd.

  16. Confidence intervals for the common intraclass correlation in the analysis of clustered binary responses.

    Science.gov (United States)

    Saha, Krishna K; Wang, Suojin

    2017-10-09

    In cluster randomized trials, it is often of interest to estimate the common intraclass correlation at the design stage for sample size and power calculations, which are greatly affected by the value of a common intraclass correlation. In this article, we construct confidence intervals (CIs) for the common intraclass correlation coefficient of several treatment groups. We consider the profile likelihood (PL)-based approach using the beta-binomial models and the approach based on the concept of generalized pivots using the ANOVA estimator and its asymptotic variance. We compare both approaches with a number of large sample procedures as well as both parametric and nonparametric bootstrap procedures in terms of coverage and expected CI length through a simulation study, and illustrate the methodology with two examples from biomedical fields. The results support the use of the PL-based CI as it holds the preassigned confidence level very well and overall gives a very competitive length.

  17. Rescaled Range Analysis and Detrended Fluctuation Analysis: Finite Sample Properties and Confidence Intervals

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav

    4/2010, č. 3 (2010), s. 236-250 ISSN 1802-4696 R&D Projects: GA ČR GD402/09/H045; GA ČR GA402/09/0965 Grant - others:GA UK(CZ) 118310 Institutional research plan: CEZ:AV0Z10750506 Keywords : rescaled range analysis * detrended fluctuation analysis * Hurst exponent * long-range dependence Subject RIV: AH - Economics http://library.utia.cas.cz/separaty/2010/E/kristoufek-rescaled range analysis and detrended fluctuation analysis finite sample properties and confidence intervals.pdf

  18. A NEW METHOD FOR CONSTRUCTING CONFIDENCE INTERVAL FOR CPM BASED ON FUZZY DATA

    Directory of Open Access Journals (Sweden)

    Bahram Sadeghpour Gildeh

    2011-06-01

    Full Text Available A measurement control system ensures that measuring equipment and measurement processes are fit for their intended use and its importance in achieving product quality objectives. In most real life applications, the observations are fuzzy. In some cases specification limits (SLs are not precise numbers and they are expressed in fuzzy terms, s o that the classical capability indices could not be applied. In this paper we obtain 100(1 - α% fuzzy confidence interval for C pm fuzzy process capability index, where instead of precise quality we have two membership functions for specification limits.

  19. Neural network based load and price forecasting and confidence interval estimation in deregulated power markets

    Science.gov (United States)

    Zhang, Li

    With the deregulation of the electric power market in New England, an independent system operator (ISO) has been separated from the New England Power Pool (NEPOOL). The ISO provides a regional spot market, with bids on various electricity-related products and services submitted by utilities and independent power producers. A utility can bid on the spot market and buy or sell electricity via bilateral transactions. Good estimation of market clearing prices (MCP) will help utilities and independent power producers determine bidding and transaction strategies with low risks, and this is crucial for utilities to compete in the deregulated environment. MCP prediction, however, is difficult since bidding strategies used by participants are complicated and MCP is a non-stationary process. The main objective of this research is to provide efficient short-term load and MCP forecasting and corresponding confidence interval estimation methodologies. In this research, the complexity of load and MCP with other factors is investigated, and neural networks are used to model the complex relationship between input and output. With improved learning algorithm and on-line update features for load forecasting, a neural network based load forecaster was developed, and has been in daily industry use since summer 1998 with good performance. MCP is volatile because of the complexity of market behaviors. In practice, neural network based MCP predictors usually have a cascaded structure, as several key input factors need to be estimated first. In this research, the uncertainties involved in a cascaded neural network structure for MCP prediction are analyzed, and prediction distribution under the Bayesian framework is developed. A fast algorithm to evaluate the confidence intervals by using the memoryless Quasi-Newton method is also developed. The traditional back-propagation algorithm for neural network learning needs to be improved since MCP is a non-stationary process. The extended Kalman

  20. A Smooth Bootstrap Procedure towards Deriving Confidence Intervals for the Relative Risk.

    Science.gov (United States)

    Wang, Dongliang; Hutson, Alan D

    Given a pair of sample estimators of two independent proportions, bootstrap methods are a common strategy towards deriving the associated confidence interval for the relative risk. We develop a new smooth bootstrap procedure, which generates pseudo-samples from a continuous quantile function. Under a variety of settings, our simulation studies show that our method possesses a better or equal performance in comparison with asymptotic theory based and existing bootstrap methods, particularly for heavily unbalanced data in terms of coverage probability and power. We illustrate our procedure as applied to several published data sets.

  1. Assessment of individual agreements with repeated measurements based on generalized confidence intervals.

    Science.gov (United States)

    Quiroz, Jorge; Burdick, Richard K

    2009-01-01

    Individual agreement between two measurement systems is determined using the total deviation index (TDI) or the coverage probability (CP) criteria as proposed by Lin (2000) and Lin et al. (2002). We used a variance component model as proposed by Choudhary (2007). Using the bootstrap approach, Choudhary (2007), and generalized confidence intervals, we construct bounds on TDI and CP. A simulation study was conducted to assess whether the bounds maintain the stated type I error probability of the test. We also present a computational example to demonstrate the statistical methods described in the paper.

  2. Reliability of confidence intervals calculated by bootstrap and classical methods using the FIA 1-ha plot design

    Science.gov (United States)

    H. T. Schreuder; M. S. Williams

    2000-01-01

    In simulation sampling from forest populations using sample sizes of 20, 40, and 60 plots respectively, confidence intervals based on the bootstrap (accelerated, percentile, and t-distribution based) were calculated and compared with those based on the classical t confidence intervals for mapped populations and subdomains within those populations. A 68.1 ha mapped...

  3. Accuracy in Parameter Estimation for the Root Mean Square Error of Approximation: Sample Size Planning for Narrow Confidence Intervals

    Science.gov (United States)

    Kelley, Ken; Lai, Keke

    2011-01-01

    The root mean square error of approximation (RMSEA) is one of the most widely reported measures of misfit/fit in applications of structural equation modeling. When the RMSEA is of interest, so too should be the accompanying confidence interval. A narrow confidence interval reveals that the plausible parameter values are confined to a relatively…

  4. Another look at confidence intervals: Proposal for a more relevant and transparent approach

    Energy Technology Data Exchange (ETDEWEB)

    Biller, Steven D., E-mail: steven.biller@physics.ox.ac.uk [Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Oser, Scott M. [Department of Physics and Astronomy, University of British Columbia, Vancouver V6T 1Z1 (Canada)

    2015-02-21

    The behaviors of various confidence/credible interval constructions are explored, particularly in the region of low event numbers where methods diverge most. We highlight a number of challenges, such as the treatment of nuisance parameters, and common misconceptions associated with such constructions. An informal survey of the literature suggests that confidence intervals are not always defined in relevant ways and are too often misinterpreted and/or misapplied. This can lead to seemingly paradoxical behaviors and flawed comparisons regarding the relevance of experimental results. We therefore conclude that there is a need for a more pragmatic strategy which recognizes that, while it is critical to objectively convey the information content of the data, there is also a strong desire to derive bounds on model parameter values and a natural instinct to interpret things this way. Accordingly, we attempt to put aside philosophical biases in favor of a practical view to propose a more transparent and self-consistent approach that better addresses these issues.

  5. Knowledge level of effect size statistics, confidence intervals and meta-analysis in Spanish academic psychologists.

    Science.gov (United States)

    Badenes-Ribera, Laura; Frias-Navarro, Dolores; Pascual-Soler, Marcos; Monterde-I-Bort, Héctor

    2016-11-01

    The statistical reform movement and the American Psychological Association (APA) defend the use of estimators of the effect size and its confidence intervals, as well as the interpretation of the clinical significance of the findings. A survey was conducted in which academic psychologists were asked about their behavior in designing and carrying out their studies. The sample was composed of 472 participants (45.8% men). The mean number of years as a university professor was 13.56 years (SD= 9.27). The use of effect-size estimators is becoming generalized, as well as the consideration of meta-analytic studies. However, several inadequate practices still persist. A traditional model of methodological behavior based on statistical significance tests is maintained, based on the predominance of Cohen’s d and the unadjusted R2/η2, which are not immune to outliers or departure from normality and the violations of statistical assumptions, and the under-reporting of confidence intervals of effect-size statistics. The paper concludes with recommendations for improving statistical practice.

  6. Using learning curves and confidence intervals in a time study for the calculation of standard times

    Directory of Open Access Journals (Sweden)

    Mitzy Natalia Roncancio Avila

    2017-10-01

    Full Text Available Introduction: This article explores the use of learning curves and confidence intervals in a time study carry out in a scale assembly line during a laboratory practice at the University of La Salle. Objective: The objective of this research is to show the use of confidence intervals and learning curves for the identification of stable processes and subsequent standardization of timing Methodology: The methodology used consists in two phases: Analysis for the study of times and establishment of standard times; the first consist in the calculation of the number of cycles, depuration of atypical data and the use of the curves to determine the processes suitable for the standardization, and the second phase is the calculation of the standard times. Results: The analysis allowed to determine that is only possible to standardize two of the five processes of the system under study because of the variability of them. Conclusions: Given the research, is possible to conclude that a process should be standardized only if it presents a stable behavior respect to the normal rhythm of work, which is showed in the learning curve; otherwise, the process will obtain partial standard times.

  7. Confidence intervals for modeling anthocyanin retention in grape pomace during nonisothermal heating.

    Science.gov (United States)

    Mishra, D K; Dolan, K D; Yang, L

    2008-01-01

    Degradation of nutraceuticals in low- and intermediate-moisture foods heated at high temperature (>100 degrees C) is difficult to model because of the nonisothermal condition. Isothermal experiments above 100 degrees C are difficult to design because they require high pressure and small sample size in sealed containers. Therefore, a nonisothermal method was developed to estimate the thermal degradation kinetic parameter of nutraceuticals and determine the confidence intervals for the parameters and the predicted Y (concentration). Grape pomace at 42% moisture content (wb) was heated in sealed 202 x 214 steel cans in a steam retort at 126.7 degrees C for > 30 min. Can center temperature was measured by thermocouple and predicted using Comsol software. Thermal conductivity (k) and specific heat (C(p)) were estimated as quadratic functions of temperature using Comsol and nonlinear regression. The k and C(p) functions were then used to predict temperature inside the grape pomace during retorting. Similar heating experiments were run at different time-temperature treatments from 8 to 25 min for kinetic parameter estimation. Anthocyanin concentration in the grape pomace was measured using HPLC. Degradation rate constant (k(110 degrees C)) and activation energy (E(a)) were estimated using nonlinear regression. The thermophysical properties estimates at 100 degrees C were k = 0.501 W/m degrees C, Cp= 3600 J/kg and the kinetic parameters were k(110 degrees C)= 0.0607/min and E(a)= 65.32 kJ/mol. The 95% confidence intervals for the parameters and the confidence bands and prediction bands for anthocyanin retention were plotted. These methods are useful for thermal processing design for nutraceutical products.

  8. Random effects meta-analysis: Coverage performance of 95% confidence and prediction intervals following REML estimation.

    Science.gov (United States)

    Partlett, Christopher; Riley, Richard D

    2017-01-30

    A random effects meta-analysis combines the results of several independent studies to summarise the evidence about a particular measure of interest, such as a treatment effect. The approach allows for unexplained between-study heterogeneity in the true treatment effect by incorporating random study effects about the overall mean. The variance of the mean effect estimate is conventionally calculated by assuming that the between study variance is known; however, it has been demonstrated that this approach may be inappropriate, especially when there are few studies. Alternative methods that aim to account for this uncertainty, such as Hartung-Knapp, Sidik-Jonkman and Kenward-Roger, have been proposed and shown to improve upon the conventional approach in some situations. In this paper, we use a simulation study to examine the performance of several of these methods in terms of the coverage of the 95% confidence and prediction intervals derived from a random effects meta-analysis estimated using restricted maximum likelihood. We show that, in terms of the confidence intervals, the Hartung-Knapp correction performs well across a wide-range of scenarios and outperforms other methods when heterogeneity was large and/or study sizes were similar. However, the coverage of the Hartung-Knapp method is slightly too low when the heterogeneity is low (I 2   30%) and study sizes are similar. In other situations, especially when heterogeneity is small and the study sizes are quite varied, the coverage is far too low and could not be consistently improved by either increasing the number of studies, altering the degrees of freedom or using variance inflation methods. Therefore, researchers should be cautious in deriving 95% prediction intervals following a frequentist random-effects meta-analysis until a more reliable solution is identified. © 2016 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2016 The Authors. Statistics in Medicine Published by John

  9. Genome sequence-based species delimitation with confidence intervals and improved distance functions

    Science.gov (United States)

    2013-01-01

    Background For the last 25 years species delimitation in prokaryotes (Archaea and Bacteria) was to a large extent based on DNA-DNA hybridization (DDH), a tedious lab procedure designed in the early 1970s that served its purpose astonishingly well in the absence of deciphered genome sequences. With the rapid progress in genome sequencing time has come to directly use the now available and easy to generate genome sequences for delimitation of species. GBDP (Genome Blast Distance Phylogeny) infers genome-to-genome distances between pairs of entirely or partially sequenced genomes, a digital, highly reliable estimator for the relatedness of genomes. Its application as an in-silico replacement for DDH was recently introduced. The main challenge in the implementation of such an application is to produce digital DDH values that must mimic the wet-lab DDH values as close as possible to ensure consistency in the Prokaryotic species concept. Results Correlation and regression analyses were used to determine the best-performing methods and the most influential parameters. GBDP was further enriched with a set of new features such as confidence intervals for intergenomic distances obtained via resampling or via the statistical models for DDH prediction and an additional family of distance functions. As in previous analyses, GBDP obtained the highest agreement with wet-lab DDH among all tested methods, but improved models led to a further increase in the accuracy of DDH prediction. Confidence intervals yielded stable results when inferred from the statistical models, whereas those obtained via resampling showed marked differences between the underlying distance functions. Conclusions Despite the high accuracy of GBDP-based DDH prediction, inferences from limited empirical data are always associated with a certain degree of uncertainty. It is thus crucial to enrich in-silico DDH replacements with confidence-interval estimation, enabling the user to statistically evaluate the

  10. Test Statistics and Confidence Intervals to Establish Noninferiority between Treatments with Ordinal Categorical Data.

    Science.gov (United States)

    Zhang, Fanghong; Miyaoka, Etsuo; Huang, Fuping; Tanaka, Yutaka

    2015-01-01

    The problem for establishing noninferiority is discussed between a new treatment and a standard (control) treatment with ordinal categorical data. A measure of treatment effect is used and a method of specifying noninferiority margin for the measure is provided. Two Z-type test statistics are proposed where the estimation of variance is constructed under the shifted null hypothesis using U-statistics. Furthermore, the confidence interval and the sample size formula are given based on the proposed test statistics. The proposed procedure is applied to a dataset from a clinical trial. A simulation study is conducted to compare the performance of the proposed test statistics with that of the existing ones, and the results show that the proposed test statistics are better in terms of the deviation from nominal level and the power.

  11. Statistical variability and confidence intervals for planar dose QA pass rates

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, Daniel W.; Nelms, Benjamin E.; Attwood, Kristopher; Kumaraswamy, Lalith; Podgorsak, Matthew B. [Department of Physics, State University of New York at Buffalo, Buffalo, New York 14260 (United States) and Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Canis Lupus LLC, Merrimac, Wisconsin 53561 (United States); Department of Biostatistics, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Radiation Medicine, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States); Department of Molecular and Cellular Biophysics and Biochemistry, Roswell Park Cancer Institute, Buffalo, New York 14263 (United States) and Department of Physiology and Biophysics, State University of New York at Buffalo, Buffalo, New York 14214 (United States)

    2011-11-15

    Purpose: The most common metric for comparing measured to calculated dose, such as for pretreatment quality assurance of intensity-modulated photon fields, is a pass rate (%) generated using percent difference (%Diff), distance-to-agreement (DTA), or some combination of the two (e.g., gamma evaluation). For many dosimeters, the grid of analyzed points corresponds to an array with a low areal density of point detectors. In these cases, the pass rates for any given comparison criteria are not absolute but exhibit statistical variability that is a function, in part, on the detector sampling geometry. In this work, the authors analyze the statistics of various methods commonly used to calculate pass rates and propose methods for establishing confidence intervals for pass rates obtained with low-density arrays. Methods: Dose planes were acquired for 25 prostate and 79 head and neck intensity-modulated fields via diode array and electronic portal imaging device (EPID), and matching calculated dose planes were created via a commercial treatment planning system. Pass rates for each dose plane pair (both centered to the beam central axis) were calculated with several common comparison methods: %Diff/DTA composite analysis and gamma evaluation, using absolute dose comparison with both local and global normalization. Specialized software was designed to selectively sample the measured EPID response (very high data density) down to discrete points to simulate low-density measurements. The software was used to realign the simulated detector grid at many simulated positions with respect to the beam central axis, thereby altering the low-density sampled grid. Simulations were repeated with 100 positional iterations using a 1 detector/cm{sup 2} uniform grid, a 2 detector/cm{sup 2} uniform grid, and similar random detector grids. For each simulation, %/DTA composite pass rates were calculated with various %Diff/DTA criteria and for both local and global %Diff normalization

  12. Test-compatible confidence intervals for adaptive two-stage single-arm designs with binary endpoint.

    Science.gov (United States)

    Kunzmann, Kevin; Kieser, Meinhard

    2018-01-01

    Inference after two-stage single-arm designs with binary endpoint is challenging due to the nonunique ordering of the sampling space in multistage designs. We illustrate the problem of specifying test-compatible confidence intervals for designs with nonconstant second-stage sample size and present two approaches that guarantee confidence intervals consistent with the test decision. Firstly, we extend the well-known Clopper-Pearson approach of inverting a family of two-sided hypothesis tests from the group-sequential case to designs with fully adaptive sample size. Test compatibility is achieved by using a sample space ordering that is derived from a test-compatible estimator. The resulting confidence intervals tend to be conservative but assure the nominal coverage probability. In order to assess the possibility of further improving these confidence intervals, we pursue a direct optimization approach minimizing the mean width of the confidence intervals. While the latter approach produces more stable coverage probabilities, it is also slightly anti-conservative and yields only negligible improvements in mean width. We conclude that the Clopper-Pearson-type confidence intervals based on a test-compatible estimator are the best choice if the nominal coverage probability is not to be undershot and compatibility of test decision and confidence interval is to be preserved. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Standardized likelihood ratio test for comparing several log-normal means and confidence interval for the common mean.

    Science.gov (United States)

    Krishnamoorthy, K; Oral, Evrim

    2017-12-01

    Standardized likelihood ratio test (SLRT) for testing the equality of means of several log-normal distributions is proposed. The properties of the SLRT and an available modified likelihood ratio test (MLRT) and a generalized variable (GV) test are evaluated by Monte Carlo simulation and compared. Evaluation studies indicate that the SLRT is accurate even for small samples, whereas the MLRT could be quite liberal for some parameter values, and the GV test is in general conservative and less powerful than the SLRT. Furthermore, a closed-form approximate confidence interval for the common mean of several log-normal distributions is developed using the method of variance estimate recovery, and compared with the generalized confidence interval with respect to coverage probabilities and precision. Simulation studies indicate that the proposed confidence interval is accurate and better than the generalized confidence interval in terms of coverage probabilities. The methods are illustrated using two examples.

  14. Why the p Value Alone Is Not Enough: The Need for Confidence Intervals in Plastic Surgery Research.

    Science.gov (United States)

    Samargandi, Osama A; Al-Taha, Mona; Moran, Kit; Al Youha, Sarah; Bezuhly, Michael

    2018-01-01

    The p value is one of the most used descriptors in statistical analysis; however, when reported in isolation, it does not convey the effect size of a treatment. The reporting of confidence intervals is an essential adjunct to determine the clinical value of treatment, as it permits an assessment of the effect size. The authors assessed the reporting of confidence intervals in clinical trials within the plastic surgery literature. The seven highest impact plastic surgery journals were screened using MEDLINE for clinical trials in the years 2006, 2009, 2012, and 2015. Studies were randomized based on a predetermined sample size, and various characteristics (e.g., Jadad quality score, reporting of statistical significance, journal impact factor, and participation of an individual with formal research training) were documented. Two independent reviewers analyzed 135 articles. There was substantial interrater agreement (kappa = 0.78). Although 86.7 percent of studies reported a p value, only 25.2 percent reported confidence intervals. Of all journals assessed, Plastic and Reconstructive Surgery most frequently reported confidence intervals. The quality of the studies had a median Jadad score of 2 of 5. Bivariate analysis revealed that higher Jadad score and involvement of an individual with formal research training were associated with reporting of confidence intervals. Multivariate analysis revealed similar findings, whereas journal impact factor, year of publication, and statistical significance were not correlated with confidence interval reporting. Confidence intervals are underreported in the plastic surgery literature. To improve reporting quality of clinical trials, results should always include the confidence intervals to avoid misinterpretation of the effect size of a statistically significant result.

  15. Applications of asymptotic confidence intervals with continuity corrections for asymmetric comparisons in noninferiority trials.

    Science.gov (United States)

    Soulakova, Julia N; Bright, Brianna C

    2013-01-01

    A large-sample problem of illustrating noninferiority of an experimental treatment over a referent treatment for binary outcomes is considered. The methods of illustrating noninferiority involve constructing the lower two-sided confidence bound for the difference between binomial proportions corresponding to the experimental and referent treatments and comparing it with the negative value of the noninferiority margin. The three considered methods, Anbar, Falk-Koch, and Reduced Falk-Koch, handle the comparison in an asymmetric way, that is, only the referent proportion out of the two, experimental and referent, is directly involved in the expression for the variance of the difference between two sample proportions. Five continuity corrections (including zero) are considered with respect to each approach. The key properties of the corresponding methods are evaluated via simulations. First, the uncorrected two-sided confidence intervals can, potentially, have smaller coverage probability than the nominal level even for moderately large sample sizes, for example, 150 per group. Next, the 15 testing methods are discussed in terms of their Type I error rate and power. In the settings with a relatively small referent proportion (about 0.4 or smaller), the Anbar approach with Yates' continuity correction is recommended for balanced designs and the Falk-Koch method with Yates' correction is recommended for unbalanced designs. For relatively moderate (about 0.6) and large (about 0.8 or greater) referent proportion, the uncorrected Reduced Falk-Koch method is recommended, although in this case, all methods tend to be over-conservative. These results are expected to be used in the design stage of a noninferiority study when asymmetric comparisons are envisioned. Copyright © 2013 John Wiley & Sons, Ltd.

  16. Determination of confidence intervals in non-normal data: application of the bootstrap to cocaine concentration in femoral blood.

    Science.gov (United States)

    Desharnais, Brigitte; Camirand-Lemyre, Félix; Mireault, Pascal; Skinner, Cameron D

    2015-03-01

    Calculating the confidence interval is a common procedure in data analysis and is readily obtained from normally distributed populations with the familiar [Formula: see text] formula. However, when working with non-normally distributed data, determining the confidence interval is not as obvious. For this type of data, there are fewer references in the literature, and they are much less accessible. We describe, in simple language, the percentile and bias-corrected and accelerated variations of the bootstrap method to calculate confidence intervals. This method can be applied to a wide variety of parameters (mean, median, slope of a calibration curve, etc.) and is appropriate for normal and non-normal data sets. As a worked example, the confidence interval around the median concentration of cocaine in femoral blood is calculated using bootstrap techniques. The median of the non-toxic concentrations was 46.7 ng/mL with a 95% confidence interval of 23.9-85.8 ng/mL in the non-normally distributed set of 45 postmortem cases. This method should be used to lead to more statistically sound and accurate confidence intervals for non-normally distributed populations, such as reference values of therapeutic and toxic drug concentration, as well as situations of truncated concentration values near the limit of quantification or cutoff of a method. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Uncertainty in population growth rates: determining confidence intervals from point estimates of parameters.

    Directory of Open Access Journals (Sweden)

    Eleanor S Devenish Nelson

    Full Text Available BACKGROUND: Demographic models are widely used in conservation and management, and their parameterisation often relies on data collected for other purposes. When underlying data lack clear indications of associated uncertainty, modellers often fail to account for that uncertainty in model outputs, such as estimates of population growth. METHODOLOGY/PRINCIPAL FINDINGS: We applied a likelihood approach to infer uncertainty retrospectively from point estimates of vital rates. Combining this with resampling techniques and projection modelling, we show that confidence intervals for population growth estimates are easy to derive. We used similar techniques to examine the effects of sample size on uncertainty. Our approach is illustrated using data on the red fox, Vulpes vulpes, a predator of ecological and cultural importance, and the most widespread extant terrestrial mammal. We show that uncertainty surrounding estimated population growth rates can be high, even for relatively well-studied populations. Halving that uncertainty typically requires a quadrupling of sampling effort. CONCLUSIONS/SIGNIFICANCE: Our results compel caution when comparing demographic trends between populations without accounting for uncertainty. Our methods will be widely applicable to demographic studies of many species.

  18. Confidence intervals permit, but don't guarantee, better inference than statistical significance testing

    Directory of Open Access Journals (Sweden)

    Melissa Coulson

    2010-07-01

    Full Text Available A statistically significant result, and a non-significant result may differ little, although significance status may tempt an interpretation of difference. Two studies are reported that compared interpretation of such results presented using null hypothesis significance testing (NHST, or confidence intervals (CIs. Authors of articles published in psychology, behavioural neuroscience, and medical journals were asked, via email, to interpret two fictitious studies that found similar results, one statistically significant, and the other non-significant. Responses from 330 authors varied greatly, but interpretation was generally poor, whether results were presented as CIs or using NHST. However, when interpreting CIs respondents who mentioned NHST were 60% likely to conclude, unjustifiably, the two results conflicted, whereas those who interpreted CIs without reference to NHST were 95% likely to conclude, justifiably, the two results were consistent. Findings were generally similar for all three disciplines. An email survey of academic psychologists confirmed that CIs elicit better interpretations if NHST is not invoked. Improved statistical inference can result from encouragement of meta-analytic thinking and use of CIs but, for full benefit, such highly desirable statistical reform requires also that researchers interpret CIs without recourse to NHST.

  19. Confidence intervals for the difference of marginal probabilities in clustered matched-pair binary data.

    Science.gov (United States)

    Yang, Zhao; Sun, Xuezheng; Hardin, James W

    2012-01-01

    Although there are several available test statistics to assess the difference of marginal probabilities in clustered matched-pair binary data, associated confidence intervals (CIs) are not readily available. Herein, the construction of corresponding CIs is proposed, and the performance of each CI is investigated. The results from Monte Carlo simulation study indicate that the proposed CIs perform well in maintaining the nominal coverage probability: for small to medium numbers of clusters, the intracluster correlation coefficient-adjusted McNemar statistic and its associated Wald or Score CIs are preferred; however, this statistic becomes conservative when the number of clusters is larger so that alternative statistics and their associated CIs are preferred. In practice, a combination of the intracluster correlation coefficient-adjusted McNemar statistic with an alternative statistic is recommended. To illustrate the practical application, a real clustered matched-pair collection of data is used to illustrate testing the difference of marginal probabilities and constructing the associated CIs. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Standard Errors and Confidence Intervals of Norm Statistics for Educational and Psychological Tests.

    Science.gov (United States)

    Oosterhuis, Hannah E M; van der Ark, L Andries; Sijtsma, Klaas

    2016-11-14

    Norm statistics allow for the interpretation of scores on psychological and educational tests, by relating the test score of an individual test taker to the test scores of individuals belonging to the same gender, age, or education groups, et cetera. Given the uncertainty due to sampling error, one would expect researchers to report standard errors for norm statistics. In practice, standard errors are seldom reported; they are either unavailable or derived under strong distributional assumptions that may not be realistic for test scores. We derived standard errors for four norm statistics (standard deviation, percentile ranks, stanine boundaries and Z-scores) under the mild assumption that the test scores are multinomially distributed. A simulation study showed that the standard errors were unbiased and that corresponding Wald-based confidence intervals had good coverage. Finally, we discuss the possibilities for applying the standard errors in practical test use in education and psychology. The procedure is provided via the R function check.norms, which is available in the mokken package.

  1. Algorithmic identification of discrepancies between published ratios and their reported confidence intervals and p-values.

    Science.gov (United States)

    Georgescu, Constantin; Wren, Jonathan D

    2017-12-22

    Studies, mostly from the operations/management literature, have shown that the rate of human error increases with task complexity. What is not known is how many errors make it into the published literature, given that they must slip by peer-review. By identifying paired, dependent values within text for reported calculations of varying complexity, we can identify discrepancies, quantify error rates and identify mitigating factors. We extracted statistical ratios from MEDLINE abstracts (Hazard Ratio, Odds Ratio, Relative Risk), their 95% confidence intervals (CIs), and their p-values. We re-calculated the ratios and p-values using the reported CIs. For comparison, we also extracted percent-ratio pairs, one of the simplest calculation tasks. Over 486,000 published values were found and analyzed for discrepancies, allowing for rounding and significant figures. Per reported item, discrepancies were less frequent in percent-ratio calculations (2.7%) than in ratio-CI and p-value calculations (5.6% to 7.5%), and smaller discrepancies were more frequent than large ones. Systematic discrepancies (multiple incorrect calculations of the same type) were higher for more complex tasks (14.3%) than simple ones (6.7%). Discrepancy rates decreased with increasing journal impact factor (JIF) and increasing number of authors, but with diminishing returns and JIF accounting for most of the effect. Approximately 87% of the 81,937 extracted p-values were ≤ 0.05. Using a simple, yet accurate, approach to identifying paired values within text, we offer the first quantitative evaluation of published error frequencies within these types of calculations. N/A. Jonathan-Wren@OMRF.org; jdwren@gmail.com. Available online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  2. R package to estimate intracluster correlation coefficient with confidence interval for binary data.

    Science.gov (United States)

    Chakraborty, Hrishikesh; Hossain, Akhtar

    2018-03-01

    The Intracluster Correlation Coefficient (ICC) is a major parameter of interest in cluster randomized trials that measures the degree to which responses within the same cluster are correlated. There are several types of ICC estimators and its confidence intervals (CI) suggested in the literature for binary data. Studies have compared relative weaknesses and advantages of ICC estimators as well as its CI for binary data and suggested situations where one is advantageous in practical research. The commonly used statistical computing systems currently facilitate estimation of only a very few variants of ICC and its CI. To address the limitations of current statistical packages, we developed an R package, ICCbin, to facilitate estimating ICC and its CI for binary responses using different methods. The ICCbin package is designed to provide estimates of ICC in 16 different ways including analysis of variance methods, moments based estimation, direct probabilistic methods, correlation based estimation, and resampling method. CI of ICC is estimated using 5 different methods. It also generates cluster binary data using exchangeable correlation structure. ICCbin package provides two functions for users. The function rcbin() generates cluster binary data and the function iccbin() estimates ICC and it's CI. The users can choose appropriate ICC and its CI estimate from the wide selection of estimates from the outputs. The R package ICCbin presents very flexible and easy to use ways to generate cluster binary data and to estimate ICC and it's CI for binary response using different methods. The package ICCbin is freely available for use with R from the CRAN repository (https://cran.r-project.org/package=ICCbin). We believe that this package can be a very useful tool for researchers to design cluster randomized trials with binary outcome. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Adjusted Wald Confidence Interval for a Difference of Binomial Proportions Based on Paired Data

    Science.gov (United States)

    Bonett, Douglas G.; Price, Robert M.

    2012-01-01

    Adjusted Wald intervals for binomial proportions in one-sample and two-sample designs have been shown to perform about as well as the best available methods. The adjusted Wald intervals are easy to compute and have been incorporated into introductory statistics courses. An adjusted Wald interval for paired binomial proportions is proposed here and…

  4. Standard errors and confidence intervals for correlations corrected for indirect range restriction: A simulation study comparing analytic and bootstrap methods.

    Science.gov (United States)

    Kennet-Cohen, Tamar; Kleper, Dvir; Turvall, Elliot

    2018-02-01

    A frequent topic of psychological research is the estimation of the correlation between two variables from a sample that underwent a selection process based on a third variable. Due to indirect range restriction, the sample correlation is a biased estimator of the population correlation, and a correction formula is used. In the past, bootstrap standard error and confidence intervals for the corrected correlations were examined with normal data. The present study proposes a large-sample estimate (an analytic method) for the standard error, and a corresponding confidence interval for the corrected correlation. Monte Carlo simulation studies involving both normal and non-normal data were conducted to examine the empirical performance of the bootstrap and analytic methods. Results indicated that with both normal and non-normal data, the bootstrap standard error and confidence interval were generally accurate across simulation conditions (restricted sample size, selection ratio, and population correlations) and outperformed estimates of the analytic method. However, with certain combinations of distribution type and model conditions, the analytic method has an advantage, offering reasonable estimates of the standard error and confidence interval without resorting to the bootstrap procedure's computer-intensive approach. We provide SAS code for the simulation studies. © 2017 The British Psychological Society.

  5. Coverage probability of bootstrap confidence intervals in heavy-tailed frequency models, with application to precipitation data

    Czech Academy of Sciences Publication Activity Database

    Kyselý, Jan

    2010-01-01

    Roč. 101, 3-4 (2010), s. 345-361 ISSN 0177-798X R&D Projects: GA AV ČR KJB300420801 Institutional research plan: CEZ:AV0Z30420517 Keywords : bootstrap * extreme value analysis * confidence intervals * heavy-tailed distributions * precipitation amounts Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.684, year: 2010

  6. Population Validity and Cross-Validity: Applications of Distribution Theory for Testing Hypotheses, Setting Confidence Intervals, and Determining Sample Size

    Science.gov (United States)

    Algina, James; Keselman, H. J.

    2008-01-01

    Applications of distribution theory for the squared multiple correlation coefficient and the squared cross-validation coefficient are reviewed, and computer programs for these applications are made available. The applications include confidence intervals, hypothesis testing, and sample size selection. (Contains 2 tables.)

  7. Confidence Intervals for Effect Sizes: Compliance and Clinical Significance in the "Journal of Consulting and Clinical Psychology"

    Science.gov (United States)

    Odgaard, Eric C.; Fowler, Robert L.

    2010-01-01

    Objective: In 2005, the "Journal of Consulting and Clinical Psychology" ("JCCP") became the first American Psychological Association (APA) journal to require statistical measures of clinical significance, plus effect sizes (ESs) and associated confidence intervals (CIs), for primary outcomes (La Greca, 2005). As this represents the single largest…

  8. A computer program (COSTUM) to calculate confidence intervals for in situ stress measurements. V. 1

    International Nuclear Information System (INIS)

    Dzik, E.J.; Walker, J.R.; Martin, C.D.

    1989-03-01

    The state of in situ stress is one of the parameters required both for the design and analysis of underground excavations and for the evaluation of numerical models used to simulate underground conditions. To account for the variability and uncertainty of in situ stress measurements, it is desirable to apply confidence limits to measured stresses. Several measurements of the state of stress along a borehole are often made to estimate the average state of stress at a point. Since stress is a tensor, calculating the mean stress and confidence limits using scalar techniques is inappropriate as well as incorrect. A computer program has been written to calculate and present the mean principle stresses and the confidence limits for the magnitudes and directions of the mean principle stresses. This report describes the computer program, COSTUM

  9. The confidence-accuracy relationship for eyewitness identification decisions: Effects of exposure duration, retention interval, and divided attention.

    Science.gov (United States)

    Palmer, Matthew A; Brewer, Neil; Weber, Nathan; Nagesh, Ambika

    2013-03-01

    Prior research points to a meaningful confidence-accuracy (CA) relationship for positive identification decisions. However, there are theoretical grounds for expecting that different aspects of the CA relationship (calibration, resolution, and over/underconfidence) might be undermined in some circumstances. This research investigated whether the CA relationship for eyewitness identification decisions is affected by three, forensically relevant variables: exposure duration, retention interval, and divided attention at encoding. In Study 1 (N = 986), a field experiment, we examined the effects of exposure duration (5 s vs. 90 s) and retention interval (immediate testing vs. a 1-week delay) on the CA relationship. In Study 2 (N = 502), we examined the effects of attention during encoding on the CA relationship by reanalyzing data from a laboratory experiment in which participants viewed a stimulus video under full or divided attention conditions and then attempted to identify two targets from separate lineups. Across both studies, all three manipulations affected identification accuracy. The central analyses concerned the CA relation for positive identification decisions. For the manipulations of exposure duration and retention interval, overconfidence was greater in the more difficult conditions (shorter exposure; delayed testing) than the easier conditions. Only the exposure duration manipulation influenced resolution (which was better for 5 s than 90 s), and only the retention interval manipulation affected calibration (which was better for immediate testing than delayed testing). In all experimental conditions, accuracy and diagnosticity increased with confidence, particularly at the upper end of the confidence scale. Implications for theory and forensic settings are discussed.

  10. The best confidence interval of the failure rate and unavailability per demand when few experimental data are available

    International Nuclear Information System (INIS)

    Goodman, J.

    1985-01-01

    Using a few available data the likelihood functions for the failure rate and unavailability per demand are constructed. These likelihood functions are used to obtain likelihood density functions for the failure rate and unavailability per demand. The best (or shortest) confidence intervals for these functions are provided. The failure rate and unavailability per demand are important characteristics needed for reliability and availability analysis. The methods of estimation of these characteristics when plenty of observed data are available are well known. However, on many occasions when we deal with rare failure modes or with new equipment or components for which sufficient experience has not accumulated, we have scarce data where few or zero failures have occurred. In these cases, a technique which reflects exactly our state of knowledge is required. This technique is based on likelihood density function or Bayesian methods depending on the available prior distribution. To extract the maximum amount of information from the data the best confidence interval is determined

  11. [Confidence interval or p-value--similarities and differences between two important methods of statistical inference of quantitative studies].

    Science.gov (United States)

    Harari, Gil

    2014-01-01

    Statistic significance, also known as p-value, and CI (Confidence Interval) are common statistics measures and are essential for the statistical analysis of studies in medicine and life sciences. These measures provide complementary information about the statistical probability and conclusions regarding the clinical significance of study findings. This article is intended to describe the methodologies, compare between the methods, assert their suitability for the different needs of study results analysis and to explain situations in which each method should be used.

  12. Monte Carlo simulation of parameter confidence intervals for non-linear regression analysis of biological data using Microsoft Excel.

    Science.gov (United States)

    Lambert, Ronald J W; Mytilinaios, Ioannis; Maitland, Luke; Brown, Angus M

    2012-08-01

    This study describes a method to obtain parameter confidence intervals from the fitting of non-linear functions to experimental data, using the SOLVER and Analysis ToolPaK Add-In of the Microsoft Excel spreadsheet. Previously we have shown that Excel can fit complex multiple functions to biological data, obtaining values equivalent to those returned by more specialized statistical or mathematical software. However, a disadvantage of using the Excel method was the inability to return confidence intervals for the computed parameters or the correlations between them. Using a simple Monte-Carlo procedure within the Excel spreadsheet (without recourse to programming), SOLVER can provide parameter estimates (up to 200 at a time) for multiple 'virtual' data sets, from which the required confidence intervals and correlation coefficients can be obtained. The general utility of the method is exemplified by applying it to the analysis of the growth of Listeria monocytogenes, the growth inhibition of Pseudomonas aeruginosa by chlorhexidine and the further analysis of the electrophysiological data from the compound action potential of the rodent optic nerve. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  13. Technical Report: Algorithm and Implementation for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, Kevin [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-11

    This report describes the design and implementation of an algorithm for estimating relative microbial abundances, together with confidence limits, using data from metagenomic DNA sequencing. For the background behind this project and a detailed discussion of our modeling approach for metagenomic data, we refer the reader to our earlier technical report, dated March 4, 2014. Briefly, we described a fully Bayesian generative model for paired-end sequence read data, incorporating the effects of the relative abundances, the distribution of sequence fragment lengths, fragment position bias, sequencing errors and variations between the sampled genomes and the nearest reference genomes. A distinctive feature of our modeling approach is the use of a Chinese restaurant process (CRP) to describe the selection of genomes to be sampled, and thus the relative abundances. The CRP component is desirable for fitting abundances to reads that may map ambiguously to multiple targets, because it naturally leads to sparse solutions that select the best representative from each set of nearly equivalent genomes.

  14. A program for confidence interval calculations for a Poisson process with background including systematic uncertainties: POLE 1.0

    Science.gov (United States)

    Conrad, Jan

    2004-04-01

    A Fortran 77 routine has been developed to calculate confidence intervals with and without systematic uncertainties using a frequentist confidence interval construction with a Bayesian treatment of the systematic uncertainties. The routine can account for systematic uncertainties in the background prediction and signal/background efficiencies. The uncertainties may be separately parametrized by a Gauss, log-normal or flat probability density function (PDF), though since a Monte Carlo approach is chosen to perform the necessary integrals a generalization to other parameterizations is particularly simple. Full correlation between signal and background efficiency is optional. The ordering schemes for frequentist construction currently supported are the likelihood ratio ordering (also known as Feldman-Cousins) and Neyman ordering. Optionally, both schemes can be used with conditioning, meaning the probability density function is conditioned on the fact that the actual outcome of the background process can not have been larger than the number of observed events. Program summaryTitle of program: POLE version 1.0 Catalogue identifier: ADTA Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTA Program available from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: None Computer for which the program is designed: DELL PC 1 GB 2.0 Ghz Pentium IV Operating system under which the program has been tested: RH Linux 7.2 Kernel 2.4.7-10 Programming language used: Fortran 77 Memory required to execute with typical data: ˜1.6 Mbytes No. of bytes in distributed program, including test data, etc.: 373745 No. of lines in distributed program, including test data, etc.: 2700 Distribution format: tar gzip file Keywords: Confidence interval calculation, Systematic uncertainties Nature of the physical problem: The problem is to calculate a frequentist confidence interval on the parameter of a Poisson process with known background in presence of

  15. Experimental optimization of the number of blocks by means of algorithms parameterized by confidence interval in popcorn breeding.

    Science.gov (United States)

    Paula, T O M; Marinho, C D; Amaral Júnior, A T; Peternelli, L A; Gonçalves, L S A

    2013-06-27

    The objective of this study was to determine the optimal number of repetitions to be used in competition trials of popcorn traits related to production and quality, including grain yield and expansion capacity. The experiments were conducted in 3 environments representative of the north and northwest regions of the State of Rio de Janeiro with 10 Brazilian genotypes of popcorn, consisting by 4 commercial hybrids (IAC 112, IAC 125, Zélia, and Jade), 4 improved varieties (BRS Ângela, UFVM-2 Barão de Viçosa, Beija-flor, and Viçosa) and 2 experimental populations (UNB2U-C3 and UNB2U-C4). The experimental design utilized was a randomized complete block design with 7 repetitions. The Bootstrap method was employed to obtain samples of all of the possible combinations within the 7 blocks. Subsequently, the confidence intervals of the parameters of interest were calculated for all simulated data sets. The optimal number of repetition for all of the traits was considered when all of the estimates of the parameters in question were encountered within the confidence interval. The estimates of the number of repetitions varied according to the parameter estimated, variable evaluated, and environment cultivated, ranging from 2 to 7. It is believed that only the expansion capacity traits in the Colégio Agrícola environment (for residual variance and coefficient of variation), and number of ears per plot, in the Itaocara environment (for coefficient of variation) needed 7 repetitions to fall within the confidence interval. Thus, for the 3 studies conducted, we can conclude that 6 repetitions are optimal for obtaining high experimental precision.

  16. Generalized Confidence Intervals for Intra- and Inter-subject Coefficients of Variation in Linear Mixed-effects Models.

    Science.gov (United States)

    Forkman, Johannes

    2017-06-15

    Linear mixed-effects models are linear models with several variance components. Models with a single random-effects factor have two variance components: the random-effects variance, i. e., the inter-subject variance, and the residual error variance, i. e., the intra-subject variance. In many applications, it is practice to report variance components as coefficients of variation. The intra- and inter-subject coefficients of variation are the square roots of the corresponding variances divided by the mean. This article proposes methods for computing confidence intervals for intra- and inter-subject coefficients of variation using generalized pivotal quantities. The methods are illustrated through two examples. In the first example, precision is assessed within and between runs in a bioanalytical method validation. In the second example, variation is estimated within and between main plots in an agricultural split-plot experiment. Coverage of generalized confidence intervals is investigated through simulation and shown to be close to the nominal value.

  17. Tablet potency of Tianeptine in coated tablets by near infrared spectroscopy: model optimisation, calibration transfer and confidence intervals.

    Science.gov (United States)

    Boiret, Mathieu; Meunier, Loïc; Ginot, Yves-Michel

    2011-02-20

    A near infrared (NIR) method was developed for determination of tablet potency of active pharmaceutical ingredient (API) in a complex coated tablet matrix. The calibration set contained samples from laboratory and production scale batches. The reference values were obtained by high performance liquid chromatography (HPLC) and partial least squares (PLS) regression was used to establish a model. The model was challenged by calculating tablet potency of two external test sets. Root mean square errors of prediction were respectively equal to 2.0% and 2.7%. To use this model with a second spectrometer from the production field, a calibration transfer method called piecewise direct standardisation (PDS) was used. After the transfer, the root mean square error of prediction of the first test set was 2.4% compared to 4.0% without transferring the spectra. A statistical technique using bootstrap of PLS residuals was used to estimate confidence intervals of tablet potency calculations. This method requires an optimised PLS model, selection of the bootstrap number and determination of the risk. In the case of a chemical analysis, the tablet potency value will be included within the confidence interval calculated by the bootstrap method. An easy to use graphical interface was developed to easily determine if the predictions, surrounded by minimum and maximum values, are within the specifications defined by the regulatory organisation. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Weighted profile likelihood-based confidence interval for the difference between two proportions with paired binomial data.

    Science.gov (United States)

    Pradhan, Vivek; Saha, Krishna K; Banerjee, Tathagata; Evans, John C

    2014-07-30

    Inference on the difference between two binomial proportions in the paired binomial setting is often an important problem in many biomedical investigations. Tang et al. (2010, Statistics in Medicine) discussed six methods to construct confidence intervals (henceforth, we abbreviate it as CI) for the difference between two proportions in paired binomial setting using method of variance estimates recovery. In this article, we propose weighted profile likelihood-based CIs for the difference between proportions of a paired binomial distribution. However, instead of the usual likelihood, we use weighted likelihood that is essentially making adjustments to the cell frequencies of a 2 × 2 table in the spirit of Agresti and Min (2005, Statistics in Medicine). We then conduct numerical studies to compare the performances of the proposed CIs with that of Tang et al. and Agresti and Min in terms of coverage probabilities and expected lengths. Our numerical study clearly indicates that the weighted profile likelihood-based intervals and Jeffreys interval (cf. Tang et al.) are superior in terms of achieving the nominal level, and in terms of expected lengths, they are competitive. Finally, we illustrate the use of the proposed CIs with real-life examples. Copyright © 2014 John Wiley & Sons, Ltd.

  19. Correction of confidence intervals in excess relative risk models using Monte Carlo dosimetry systems with shared errors.

    Directory of Open Access Journals (Sweden)

    Zhuo Zhang

    Full Text Available In epidemiological studies, exposures of interest are often measured with uncertainties, which may be independent or correlated. Independent errors can often be characterized relatively easily while correlated measurement errors have shared and hierarchical components that complicate the description of their structure. For some important studies, Monte Carlo dosimetry systems that provide multiple realizations of exposure estimates have been used to represent such complex error structures. While the effects of independent measurement errors on parameter estimation and methods to correct these effects have been studied comprehensively in the epidemiological literature, the literature on the effects of correlated errors, and associated correction methods is much more sparse. In this paper, we implement a novel method that calculates corrected confidence intervals based on the approximate asymptotic distribution of parameter estimates in linear excess relative risk (ERR models. These models are widely used in survival analysis, particularly in radiation epidemiology. Specifically, for the dose effect estimate of interest (increase in relative risk per unit dose, a mixture distribution consisting of a normal and a lognormal component is applied. This choice of asymptotic approximation guarantees that corrected confidence intervals will always be bounded, a result which does not hold under a normal approximation. A simulation study was conducted to evaluate the proposed method in survival analysis using a realistic ERR model. We used both simulated Monte Carlo dosimetry systems (MCDS and actual dose histories from the Mayak Worker Dosimetry System 2013, a MCDS for plutonium exposures in the Mayak Worker Cohort. Results show our proposed methods provide much improved coverage probabilities for the dose effect parameter, and noticeable improvements for other model parameters.

  20. Correction of confidence intervals in excess relative risk models using Monte Carlo dosimetry systems with shared errors

    Science.gov (United States)

    Preston, Dale L.; Sokolnikov, Mikhail; Napier, Bruce A.; Degteva, Marina; Moroz, Brian; Vostrotin, Vadim; Shiskina, Elena; Birchall, Alan; Stram, Daniel O.

    2017-01-01

    In epidemiological studies, exposures of interest are often measured with uncertainties, which may be independent or correlated. Independent errors can often be characterized relatively easily while correlated measurement errors have shared and hierarchical components that complicate the description of their structure. For some important studies, Monte Carlo dosimetry systems that provide multiple realizations of exposure estimates have been used to represent such complex error structures. While the effects of independent measurement errors on parameter estimation and methods to correct these effects have been studied comprehensively in the epidemiological literature, the literature on the effects of correlated errors, and associated correction methods is much more sparse. In this paper, we implement a novel method that calculates corrected confidence intervals based on the approximate asymptotic distribution of parameter estimates in linear excess relative risk (ERR) models. These models are widely used in survival analysis, particularly in radiation epidemiology. Specifically, for the dose effect estimate of interest (increase in relative risk per unit dose), a mixture distribution consisting of a normal and a lognormal component is applied. This choice of asymptotic approximation guarantees that corrected confidence intervals will always be bounded, a result which does not hold under a normal approximation. A simulation study was conducted to evaluate the proposed method in survival analysis using a realistic ERR model. We used both simulated Monte Carlo dosimetry systems (MCDS) and actual dose histories from the Mayak Worker Dosimetry System 2013, a MCDS for plutonium exposures in the Mayak Worker Cohort. Results show our proposed methods provide much improved coverage probabilities for the dose effect parameter, and noticeable improvements for other model parameters. PMID:28369141

  1. User guide to the UNC1NLI1 package and three utility programs for computation of nonlinear confidence and prediction intervals using MODFLOW-2000

    DEFF Research Database (Denmark)

    Christensen, Steen; Cooley, R.L.

    a model (for example when using the Parameter-Estimation Process of MODFLOW-2000) it is advantageous to also use regression-based methods to quantify uncertainty. For this reason the UNC Process computes (1) confidence intervals for parameters of the Parameter-Estimation Process and (2) confidence...

  2. Surrogate Gaussian first derivative curves for determination of decision levels and confidence intervals by binary logistic regression.

    Science.gov (United States)

    DeBari, Vincent A

    2009-01-01

    It has been demonstrated that decision levels (DL) and their confidence intervals (CI) can be estimated from the second derivative, f '' (P), of the logistic regression probability curve (LRPC). Although this method generally provides smooth curves from which DL and CI can be obtained, there are datasets that generate "noisy" curves making these measurements difficult. The purpose of this study was to develop a procedure to obviate this noise, thus allowing the more facile estimation of DL and CI. Data from two clinical studies were examined. Logistic regression analysis was performed and the first derivatives, f ' (P), were fitted to Gaussian models. The derivatives of these surrogate f ' (P) were generated to provide f '' (P) and were compared with data from receiver operating characteristic (ROC) curves. For both sets of data, the surrogate curves demonstrated strong fits to the natural f ' (P) with r(2) = 0.986 for one study and 0.832 for the second. The f '' (P) generated from the surrogate curves demonstrated single maxima (M) and minima (m), compared with the f '' (P) generated from the natural f ' (P) in which multiple M and m were observed. Easily discernible DL and CI were observed for both datasets with differences from ROC-estimated DL of 1.7% for the first study and 4.8% for the second. The use of a surrogate Gaussian simulation of f ' (P) may be a useful alternative to natural f ' (P) when using the f '' (P) of the LRPC to determine DL and CI.

  3. Determination and Interpretation of Characteristic Limits for Radioactivity Measurements: Decision Threshhold, Detection Limit and Limits of the Confidence Interval

    International Nuclear Information System (INIS)

    2017-01-01

    Since 2004, the environment programme of the IAEA has included activities aimed at developing a set of procedures for analytical measurements of radionuclides in food and the environment. Reliable, comparable and fit for purpose results are essential for any analytical measurement. Guidelines and national and international standards for laboratory practices to fulfil quality assurance requirements are extremely important when performing such measurements. The guidelines and standards should be comprehensive, clearly formulated and readily available to both the analyst and the customer. ISO 11929:2010 is the international standard on the determination of the characteristic limits (decision threshold, detection limit and limits of the confidence interval) for measuring ionizing radiation. For nuclear analytical laboratories involved in the measurement of radioactivity in food and the environment, robust determination of the characteristic limits of radioanalytical techniques is essential with regard to national and international regulations on permitted levels of radioactivity. However, characteristic limits defined in ISO 11929:2010 are complex, and the correct application of the standard in laboratories requires a full understanding of various concepts. This publication provides additional information to Member States in the understanding of the terminology, definitions and concepts in ISO 11929:2010, thus facilitating its implementation in Member State laboratories.

  4. Comparison of approaches to estimate confidence intervals of post-test probabilities of diagnostic test results in a nested case-control study

    Directory of Open Access Journals (Sweden)

    van Zaane Bas

    2012-10-01

    Full Text Available Abstract Background Nested case–control studies become increasingly popular as they can be very efficient for quantifying the diagnostic accuracy of costly or invasive tests or (biomarkers. However, they do not allow for direct estimation of the test’s predictive values or post-test probabilities, let alone for their confidence intervals (CIs. Correct estimates of the predictive values itself can easily be obtained using a simple correction by the (inverse sampling fractions of the cases and controls. But using this correction to estimate the corresponding standard error (SE, falsely increases the number of patients that are actually studied, yielding too small CIs. We compared different approaches for estimating the SE and thus CI of predictive values or post-test probabilities of diagnostic test results in a nested case–control study. Methods We created datasets based on a large, previously published diagnostic study on 2 different tests (D-dimer test and calf difference test with a nested case–control design. We compared six different approaches; the approaches were: 1. the standard formula for the SE of a proportion, 2. adaptation of the standard formula with the sampling fraction, 3. A bootstrap procedure, 4. A approach, which uses the sensitivity, the specificity and the prevalence, 5. Weighted logistic regression, and 6. Approach 4 on the log odds scale. The approaches were compared with respect to coverage of the CI and CI-width. Results The bootstrap procedure (approach 3 showed good coverage and relatively small CI widths. Approaches 4 and 6 showed some undercoverage, particularly for the D-dimer test with frequent positive results (positive results around 70%. Approaches 1, 2 and 5 showed clear overcoverage at low prevalences of 0.05 and 0.1 in the cohorts for all case–control ratios. Conclusion The results from our study suggest that a bootstrap procedure is necessary to assess the confidence interval for the predictive

  5. Using Confidence Interval-Based Estimation of Relevance to Select Social-Cognitive Determinants for Behavior Change Interventions

    Directory of Open Access Journals (Sweden)

    Rik Crutzen

    2017-07-01

    Full Text Available When developing an intervention aimed at behavior change, one of the crucial steps in the development process is to select the most relevant social-cognitive determinants. These determinants can be seen as the buttons one needs to push to establish behavior change. Insight into these determinants is needed to select behavior change methods (i.e., general behavior change techniques that are applied in an intervention in the development process. Therefore, a study on determinants is often conducted as formative research in the intervention development process. Ideally, all relevant determinants identified in such a study are addressed by an intervention. However, when developing a behavior change intervention, there are limits in terms of, for example, resources available for intervention development and the amount of content that participants of an intervention can be exposed to. Hence, it is important to select those determinants that are most relevant to the target behavior as these determinants should be addressed in an intervention. The aim of the current paper is to introduce a novel approach to select the most relevant social-cognitive determinants and use them in intervention development. This approach is based on visualization of confidence intervals for the means and correlation coefficients for all determinants simultaneously. This visualization facilitates comparison, which is necessary when making selections. By means of a case study on the determinants of using a high dose of 3,4-methylenedioxymethamphetamine (commonly known as ecstasy, we illustrate this approach. We provide a freely available tool to facilitate the analyses needed in this approach.

  6. Bootstrap Signal-to-Noise Confidence Intervals: An Objective Method for Subject Exclusion and Quality Control in ERP Studies

    Science.gov (United States)

    Parks, Nathan A.; Gannon, Matthew A.; Long, Stephanie M.; Young, Madeleine E.

    2016-01-01

    Analysis of event-related potential (ERP) data includes several steps to ensure that ERPs meet an appropriate level of signal quality. One such step, subject exclusion, rejects subject data if ERP waveforms fail to meet an appropriate level of signal quality. Subject exclusion is an important quality control step in the ERP analysis pipeline as it ensures that statistical inference is based only upon those subjects exhibiting clear evoked brain responses. This critical quality control step is most often performed simply through visual inspection of subject-level ERPs by investigators. Such an approach is qualitative, subjective, and susceptible to investigator bias, as there are no standards as to what constitutes an ERP of sufficient signal quality. Here, we describe a standardized and objective method for quantifying waveform quality in individual subjects and establishing criteria for subject exclusion. The approach uses bootstrap resampling of ERP waveforms (from a pool of all available trials) to compute a signal-to-noise ratio confidence interval (SNR-CI) for individual subject waveforms. The lower bound of this SNR-CI (SNRLB) yields an effective and objective measure of signal quality as it ensures that ERP waveforms statistically exceed a desired signal-to-noise criterion. SNRLB provides a quantifiable metric of individual subject ERP quality and eliminates the need for subjective evaluation of waveform quality by the investigator. We detail the SNR-CI methodology, establish the efficacy of employing this approach with Monte Carlo simulations, and demonstrate its utility in practice when applied to ERP datasets. PMID:26903849

  7. Five-band microwave radiometer system for noninvasive brain temperature measurement in newborn babies: Phantom experiment and confidence interval

    Science.gov (United States)

    Sugiura, T.; Hirata, H.; Hand, J. W.; van Leeuwen, J. M. J.; Mizushina, S.

    2011-10-01

    Clinical trials of hypothermic brain treatment for newborn babies are currently hindered by the difficulty in measuring deep brain temperatures. As one of the possible methods for noninvasive and continuous temperature monitoring that is completely passive and inherently safe is passive microwave radiometry (MWR). We have developed a five-band microwave radiometer system with a single dual-polarized, rectangular waveguide antenna operating within the 1-4 GHz range and a method for retrieving the temperature profile from five radiometric brightness temperatures. This paper addresses (1) the temperature calibration for five microwave receivers, (2) the measurement experiment using a phantom model that mimics the temperature profile in a newborn baby, and (3) the feasibility for noninvasive monitoring of deep brain temperatures. Temperature resolutions were 0.103, 0.129, 0.138, 0.105 and 0.111 K for 1.2, 1.65, 2.3, 3.0 and 3.6 GHz receivers, respectively. The precision of temperature estimation (2σ confidence interval) was about 0.7°C at a 5-cm depth from the phantom surface. Accuracy, which is the difference between the estimated temperature using this system and the measured temperature by a thermocouple at a depth of 5 cm, was about 2°C. The current result is not satisfactory for clinical application because the clinical requirement for accuracy must be better than 1°C for both precision and accuracy at a depth of 5 cm. Since a couple of possible causes for this inaccuracy have been identified, we believe that the system can take a step closer to the clinical application of MWR for hypothermic rescue treatment.

  8. Confidence interval estimation for an empirical model quantifying the effect of soil moisture and plant development on soybean (Glycine max (L.) Merr.) leaf conductance

    Science.gov (United States)

    In this work, we address uncertainty analysis for a model, presented in a companion paper, quantifying the effect of soil moisture and plant development on soybean (Glycine max (L.) Merr.) leaf conductance. To achieve this we present several methods for confidence interval estimation. Estimation ...

  9. Using a Nonparametric Bootstrap to Obtain a Confidence Interval for Pearson's "r" with Cluster Randomized Data: A Case Study

    Science.gov (United States)

    Wagstaff, David A.; Elek, Elvira; Kulis, Stephen; Marsiglia, Flavio

    2009-01-01

    A nonparametric bootstrap was used to obtain an interval estimate of Pearson's "r," and test the null hypothesis that there was no association between 5th grade students' positive substance use expectancies and their intentions to not use substances. The students were participating in a substance use prevention program in which the unit of…

  10. Long QT interval in Turner syndrome--a high prevalence of LQTS gene mutations.

    Directory of Open Access Journals (Sweden)

    Christian Trolle

    Full Text Available QT-interval prolongation of unknown aetiology is common in Turner syndrome. This study set out to explore the presence of known long QT mutations in Turner syndrome and to examine the corrected QT-interval (QTc over time and relate the findings to the Turner syndrome phenotype.Adult women with Turner syndrome (n = 88 were examined thrice and 68 age-matched healthy controls were examined once. QTc was measured by one blinded reader (intra-reader variability: 0.7%, and adjusted for influence of heart rate by Bazett's (bQTc and Hodges's formula (hQTc. The prevalence of mutations in genes related to Long QT syndrome was determined in women with Turner syndrome and a QTc >432.0 milliseconds (ms. Echocardiographic assessment of aortic valve morphology, 24-hour blood pressures and blood samples were done.The mean hQTc in women with Turner syndrome (414.0 ± 25.5 ms compared to controls (390.4 ± 17.8 ms was prolonged (p432 ms, 7 had mutations in major Long QT syndrome genes (SCN5A and KCNH2 and one in a minor Long QT syndrome gene (KCNE2.There is a high prevalence of mutations in the major LQTS genes in women with TS and prolonged QTc. It remains to be settled, whether these findings are related to the unexplained excess mortality in Turner women.NCT00624949. https://register.clinicaltrials.gov/prs/app/action/SelectProtocol/sid/S0001FLI/selectaction/View/ts/3/uid/U000099E.

  11. Long QT interval in Turner syndrome--a high prevalence of LQTS gene mutations.

    Science.gov (United States)

    Trolle, Christian; Mortensen, Kristian H; Pedersen, Lisbeth N; Berglund, Agnethe; Jensen, Henrik K; Andersen, Niels H; Gravholt, Claus H

    2013-01-01

    QT-interval prolongation of unknown aetiology is common in Turner syndrome. This study set out to explore the presence of known long QT mutations in Turner syndrome and to examine the corrected QT-interval (QTc) over time and relate the findings to the Turner syndrome phenotype. Adult women with Turner syndrome (n = 88) were examined thrice and 68 age-matched healthy controls were examined once. QTc was measured by one blinded reader (intra-reader variability: 0.7%), and adjusted for influence of heart rate by Bazett's (bQTc) and Hodges's formula (hQTc). The prevalence of mutations in genes related to Long QT syndrome was determined in women with Turner syndrome and a QTc >432.0 milliseconds (ms). Echocardiographic assessment of aortic valve morphology, 24-hour blood pressures and blood samples were done. The mean hQTc in women with Turner syndrome (414.0 ± 25.5 ms) compared to controls (390.4 ± 17.8 ms) was prolonged (pTurner syndrome karyotypes (418.2 ± 24.8 vs. 407.6 ± 25.5 ms; p = 0.055). In women with Turner syndrome and a bQTc >432 ms, 7 had mutations in major Long QT syndrome genes (SCN5A and KCNH2) and one in a minor Long QT syndrome gene (KCNE2). There is a high prevalence of mutations in the major LQTS genes in women with TS and prolonged QTc. It remains to be settled, whether these findings are related to the unexplained excess mortality in Turner women. NCT00624949. https://register.clinicaltrials.gov/prs/app/action/SelectProtocol/sid/S0001FLI/selectaction/View/ts/3/uid/U000099E.

  12. "Normality of Residuals Is a Continuous Variable, and Does Seem to Influence the Trustworthiness of Confidence Intervals: A Response to, and Appreciation of, Williams, Grajales, and Kurkiewicz (2013"

    Directory of Open Access Journals (Sweden)

    Jason W. Osborne

    2013-09-01

    Full Text Available Osborne and Waters (2002 focused on checking some of the assumptions of multiple linear.regression. In a critique of that paper, Williams, Grajales, and Kurkiewicz correctly clarify that.regression models estimated using ordinary least squares require the assumption of normally.distributed errors, but not the assumption of normally distributed response or predictor variables..They go on to discuss estimate bias and provide a helpful summary of the assumptions of multiple.regression when using ordinary least squares. While we were not as precise as we could have been.when discussing assumptions of normality, the critical issue of the 2002 paper remains -' researchers.often do not check on or report on the assumptions of their statistical methods. This response.expands on the points made by Williams, advocates a thorough examination of data prior to.reporting results, and provides an example of how incremental improvements in meeting the.assumption of normality of residuals incrementally improves the accuracy of confidence intervals.

  13. Zero- vs. one-dimensional, parametric vs. non-parametric, and confidence interval vs. hypothesis testing procedures in one-dimensional biomechanical trajectory analysis.

    Science.gov (United States)

    Pataky, Todd C; Vanrenterghem, Jos; Robinson, Mark A

    2015-05-01

    Biomechanical processes are often manifested as one-dimensional (1D) trajectories. It has been shown that 1D confidence intervals (CIs) are biased when based on 0D statistical procedures, and the non-parametric 1D bootstrap CI has emerged in the Biomechanics literature as a viable solution. The primary purpose of this paper was to clarify that, for 1D biomechanics datasets, the distinction between 0D and 1D methods is much more important than the distinction between parametric and non-parametric procedures. A secondary purpose was to demonstrate that a parametric equivalent to the 1D bootstrap exists in the form of a random field theory (RFT) correction for multiple comparisons. To emphasize these points we analyzed six datasets consisting of force and kinematic trajectories in one-sample, paired, two-sample and regression designs. Results showed, first, that the 1D bootstrap and other 1D non-parametric CIs were qualitatively identical to RFT CIs, and all were very different from 0D CIs. Second, 1D parametric and 1D non-parametric hypothesis testing results were qualitatively identical for all six datasets. Last, we highlight the limitations of 1D CIs by demonstrating that they are complex, design-dependent, and thus non-generalizable. These results suggest that (i) analyses of 1D data based on 0D models of randomness are generally biased unless one explicitly identifies 0D variables before the experiment, and (ii) parametric and non-parametric 1D hypothesis testing provide an unambiguous framework for analysis when one׳s hypothesis explicitly or implicitly pertains to whole 1D trajectories. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Prevalence

    Directory of Open Access Journals (Sweden)

    Jeanesse Scerri

    2013-09-01

    Full Text Available Methicillin-resistant Staphylococcus aureus (MRSA is a major nosocomial pathogen worldwide. Malta is one of the countries with the highest MRSA prevalence in Europe, as identified from hospital blood cultures [1]. However, community prevalence of MRSA has never previously been investigated. This study aimed at establishing the prevalence of community MRSA nasal colonization in Maltese individuals and identifying the clonal characteristics of the detected isolates. Nasal swabs were collected from 329 healthy individuals who were also asked to complete a brief questionnaire about risk factors commonly associated with MRSA carriage and infection. The swabs were transported and enriched in a nutrient broth supplemented with NaCl. The presence of MRSA was then determined by culturing on MRSA Select chromogenic agar and then confirming by several assays, including catalase, coagulase and PBP2a agglutination tests. The isolates were assayed for antibiotic susceptibilities and typed by microarray analysis to determine the clonal characteristics of each strain. The prevalence of MRSA nasal colonization in the healthy Maltese population was found to be 8.81% (95% confidence interval [CI], 5.75–11.87%, much higher than that found in other studies carried out in several countries. No statistical association was found between MRSA carriage and demographics or risk factors; however, this was hindered by the small sample size. Almost all the isolates were fusidic-acid resistant. The majority were found to belong to a local endemic clone (CC5 which seems to be replacing the previously prevalent European clone UK-EMRSA-15 in the country. A new clone (CC50-MRSA-V was also characterized. The presence of such a significant community reservoir of MRSA increases the burdens already faced by the local healthcare system to control the MRSA epidemic. Colonization of MRSA in otherwise healthy individuals may represent a risk for endogenous infection and transmission to

  15. Prevalence of E/A wave fusion and A wave truncation in DDD pacemaker patients with complete AV block under nominal AV intervals.

    Science.gov (United States)

    Poller, Wolfram C; Dreger, Henryk; Schwerg, Marius; Melzer, Christoph

    2015-01-01

    Optimization of the AV-interval (AVI) in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB) under the pre-programmed AVI. We manually optimized sub-optimal AVI. We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129) and under atrial pacing (AV-pace; n = 31). Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a) normal, b) too long (E/A wave fusion) or c) too short (A wave truncation). In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography. All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%). In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI): 12.6-26.2%). A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 ± 13.6 ms). Given the rate of 19.4% (CI 12.6-26.2%) of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases.

  16. Prevalence of E/A wave fusion and A wave truncation in DDD pacemaker patients with complete AV block under nominal AV intervals.

    Directory of Open Access Journals (Sweden)

    Wolfram C Poller

    Full Text Available Optimization of the AV-interval (AVI in DDD pacemakers improves cardiac hemodynamics and reduces pacemaker syndromes. Manual optimization is typically not performed in clinical routine. In the present study we analyze the prevalence of E/A wave fusion and A wave truncation under resting conditions in 160 patients with complete AV block (AVB under the pre-programmed AVI. We manually optimized sub-optimal AVI.We analyzed 160 pacemaker patients with complete AVB, both in sinus rhythm (AV-sense; n = 129 and under atrial pacing (AV-pace; n = 31. Using Doppler analyses of the transmitral inflow we classified the nominal AVI as: a normal, b too long (E/A wave fusion or c too short (A wave truncation. In patients with a sub-optimal AVI, we performed manual optimization according to the recommendations of the American Society of Echocardiography.All AVB patients with atrial pacing exhibited a normal transmitral inflow under the nominal AV-pace intervals (100%. In contrast, 25 AVB patients in sinus rhythm showed E/A wave fusion under the pre-programmed AV-sense intervals (19.4%; 95% confidence interval (CI: 12.6-26.2%. A wave truncations were not observed in any patient. All patients with a complete E/A wave fusion achieved a normal transmitral inflow after AV-sense interval reduction (mean optimized AVI: 79.4 ± 13.6 ms.Given the rate of 19.4% (CI 12.6-26.2% of patients with a too long nominal AV-sense interval, automatic algorithms may prove useful in improving cardiac hemodynamics, especially in the subgroup of atrially triggered pacemaker patients with AV node diseases.

  17. Long QT interval in Turner syndrome – a high prevalence of LQTS gene mutations

    DEFF Research Database (Denmark)

    Trolle, Christian; Mortensen, Kristian Havmand; Pedersen, Lisbeth Nørum

    Objective: QT interval prolongation of unknown aetiology is common in Turner syndrome (TS). This study set out to explore the presence of known pathogenic long QT (LQT) mutations in TS and to examine the corrected QT interval (QTc) over time and relate the findings to the TS phenotype. Methods...

  18. The Model Confidence Set

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger; Nason, James M.

    The paper introduces the model confidence set (MCS) and applies it to the selection of models. A MCS is a set of models that is constructed such that it will contain the best model with a given level of confidence. The MCS is in this sense analogous to a confidence interval for a parameter. The MCS...

  19. Prevalence of anxiety following adult traumatic brain injury: A meta-analysis comparing measures, samples and postinjury intervals.

    Science.gov (United States)

    Osborn, A J; Mathias, J L; Fairweather-Schmidt, A K

    2016-02-01

    Anxiety following a traumatic brain injury (TBI) is a common problem; however, disparate prevalence estimates limit the clinical utility of research. The purpose of the current study was to examine how differences in methodological variables and sample characteristics impact on the prevalence of anxiety. Data from 41 studies that examined either the prevalence of generalized anxiety disorder (GAD) diagnoses or clinically significant "cases" of self-reported anxiety following adult, nonpenetrating TBI were analyzed, and the impact of diagnostic criteria, measure, postinjury interval and injury severity was evaluated. Overall, 11% of people were diagnosed with GAD and 37% reported clinically significant levels of anxiety following TBI. Prevalence estimates varied for different diagnostic criteria (range: 2%-19%), interview schedules (range: 2%-28%), and self-report measures (range: 36%-50%). GAD and "cases" of anxiety were most prevalent 2 to 5 years postinjury. The rates of GAD increased with injury severity (mild: 11%, severe 15%), but "cases" decreased (mild: 53%, severe: 38%), although neither difference was significant. Anxiety is common after a TBI and ongoing monitoring and treatment should be provided. Methodological and sample characteristics should be clear and well-defined, as differences across studies (e.g., how anxiety is conceptualized, which measure is used, time since injury, injury severity) impact prevalence rates. PsycINFO Database Record (c) 2016 APA, all rights reserved.

  20. The impact of change in albumin assay on reference intervals, prevalence of 'hypoalbuminaemia' and albumin prescriptions.

    Science.gov (United States)

    Coley-Grant, Deon; Herbert, Mike; Cornes, Michael P; Barlow, Ian M; Ford, Clare; Gama, Rousseau

    2016-01-01

    We studied the impact on reference intervals, classification of patients with hypoalbuminaemia and albumin infusion prescriptions on changing from a bromocresol green (BCG) to a bromocresol purple (BCP) serum albumin assay. Passing-Bablok regression analysis and Bland-Altman plot were used to compare Abbott BCP and Roche BCG methods. Linear regression analysis was used to compare in-house and an external laboratory Abbott BCP serum albumin results. Reference intervals for Abbott BCP serum albumin were derived in two different laboratories using pathology data from adult patients in primary care. Prescriptions for 20% albumin infusions were compared one year before and one year after changing the albumin method. Abbott BCP assay had a negative bias of approximately 6 g/L compared with Roche BCG method.There was good agreement (y = 1.04 x - 1.03; R(2 )= 0.9933) between in-house and external laboratory Abbott BCP results. Reference intervals for the serum albumin Abbott BCP assay were 31-45 g/L, different to those recommended by Pathology Harmony and the manufacturers (35-50 g/L). Following the change in method there was a large increase in the number of patients classified as hypoalbuminaemic using Pathology Harmony references intervals (32%) but not when retrospectively compared to locally derived reference intervals (16%) compared with the previous year (12%). The method change was associated with a 44.6% increase in albumin prescriptions. This equated to an annual increase in expenditure of £35,234. We suggest that serum albumin reference intervals be method specific to prevent misclassification of albumin status in patients. Change in albumin methodology may have significant impact on hospital resources. © The Author(s) 2015.

  1. Prevalence and clinical relevance of corrected QT interval prolongation during methadone and buprenorphine treatment: a mortality assessment study.

    Science.gov (United States)

    Anchersen, Katinka; Clausen, Thomas; Gossop, Michael; Hansteen, Viggo; Waal, Helge

    2009-06-01

    To determine the prevalence of corrected QT interval (QTc) prolongation among patients in opioid maintenance treatment (OMT) and to investigate mortality potentially attributable to QTc prolongation in the Norwegian OMT programme. Two hundred OMT patients in Oslo were recruited to the QTc assessment study between October 2006 and August 2007. The Norwegian register of all patients receiving OMT in Norway (January 1997-December 2003) and the national death certificate register were used to assess mortality. Mortality records were examined for the 90 deaths that had occurred among 2382 patients with 6450 total years in OMT. The QTc interval was assessed by electrocardiography (ECG). All ECGs were examined by the same cardiologist, who was blind to patient history and medication. Mortality was calculated by cross-matching the OMT register and the national death certificate register: deaths that were possibly attributable to QTc prolongation were divided by the number of patient-years in OMT. In the QTc assessment sample (n = 200), 173 patients (86.5%) received methadone and 27 (13.5%) received buprenorphine. In the methadone group, 4.6% (n = 8) had a QTc above 500 milliseconds; 15% (n = 26) had a QTc interval above 470 milliseconds; and 28.9% (n = 50) had a QTc above 450 milliseconds. All patients receiving buprenorphine (n = 27) had QTc results <450 milliseconds. A positive dose-dependent association was identified between QTc length and dose of methadone, and all patients with a QTc above 500 milliseconds were taking methadone doses of 120 mg or more. OMT patient mortality, where QTc prolongation could not be excluded as the cause of death, was 0.06/100 patient-years. Only one death among 3850 OMT initiations occurred within the first month of treatment. Of the methadone patients, 4.6% had QTc intervals above 500 milliseconds. The maximum mortality attributable to QTc prolongation was low: 0.06 per 100 patient-years.

  2. Study of FibroTest and hyaluronic acid biological variation in healthy volunteers and comparison of serum hyaluronic acid biological variation between chronic liver diseases of different etiology and fibrotic stage using confidence intervals.

    Science.gov (United States)

    Istaces, Nicolas; Gulbis, Béatrice

    2015-07-01

    Personalized ranges of liver fibrosis serum biomarkers such as FibroTest or hyaluronic acid could be used for early detection of fibrotic changes in patients with progressive chronic liver disease. Our aim was to generate reliable biological variation estimates for these two biomarkers with confidence intervals for within-subject biological variation and reference change value. Nine fasting healthy volunteers and 66 chronic liver disease patients were included. Biological variation estimates were calculated for FibroTest in healthy volunteers, and for hyaluronic acid in healthy volunteers and chronic liver disease patients stratified by etiology and liver fibrosis stage. In healthy volunteers, within-subject biological coefficient of variation (with 95% confidence intervals) and index of individuality were 20% (16%-28%) and 0.6 for FibroTest and 34% (27%-47%) and 0.79 for hyaluronic acid, respectively. Overall hyaluronic acid within-subject biological coefficient of variation was similar among non-alcoholic fatty liver disease and chronic hepatitis C with 41% (34%-52%) and 45% (39%-55%), respectively, in contrast to chronic hepatitis B with 170% (140%-215%). Hyaluronic acid within-subject biological coefficients of variation were similar between F0-F1, F2 and F3 liver fibrosis stages in non-alcoholic fatty liver disease with 34% (25%-49%), 41% (31%-59%) and 34% (23%-62%), respectively, and in chronic hepatitis C with 34% (27%-47%), 33% (26%-45%) and 38% (27%-65%), respectively. However, corresponding hyaluronic acid indexes of individuality were lower in the higher fibrosis stages. Non-overlapping confidence intervals of biological variation estimates allowed us to detect significant differences regarding hyaluronic acid biological variation between chronic liver disease subgroups. Copyright © 2015 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  3. Generating confidence intervals on biological networks

    Directory of Open Access Journals (Sweden)

    Stumpf Michael PH

    2007-11-01

    Full Text Available Abstract Background In the analysis of networks we frequently require the statistical significance of some network statistic, such as measures of similarity for the properties of interacting nodes. The structure of the network may introduce dependencies among the nodes and it will in general be necessary to account for these dependencies in the statistical analysis. To this end we require some form of Null model of the network: generally rewired replicates of the network are generated which preserve only the degree (number of interactions of each node. We show that this can fail to capture important features of network structure, and may result in unrealistic significance levels, when potentially confounding additional information is available. Methods We present a new network resampling Null model which takes into account the degree sequence as well as available biological annotations. Using gene ontology information as an illustration we show how this information can be accounted for in the resampling approach, and the impact such information has on the assessment of statistical significance of correlations and motif-abundances in the Saccharomyces cerevisiae protein interaction network. An algorithm, GOcardShuffle, is introduced to allow for the efficient construction of an improved Null model for network data. Results We use the protein interaction network of S. cerevisiae; correlations between the evolutionary rates and expression levels of interacting proteins and their statistical significance were assessed for Null models which condition on different aspects of the available data. The novel GOcardShuffle approach results in a Null model for annotated network data which appears better to describe the properties of real biological networks. Conclusion An improved statistical approach for the statistical analysis of biological network data, which conditions on the available biological information, leads to qualitatively different results compared to approaches which ignore such annotations. In particular we demonstrate the effects of the biological organization of the network can be sufficient to explain the observed similarity of interacting proteins.

  4. Interpretando correctamente en salud pública estimaciones puntuales, intervalos de confianza y contrastes de hipótesis Accurate interpretation of point estimates, confidence intervals, and hypothesis tests in public health

    Directory of Open Access Journals (Sweden)

    Manuel G Scotto

    2003-12-01

    Full Text Available El presente ensayo trata de aclarar algunos conceptos utilizados habitualmente en el campo de investigación de la salud pública, que en numerosas situaciones son interpretados de manera incorrecta. Entre ellos encontramos la estimación puntual, los intervalos de confianza, y los contrastes de hipótesis. Estableciendo un paralelismo entre estos tres conceptos, podemos observar cuáles son sus diferencias más importantes a la hora de ser interpretados, tanto desde el punto de vista del enfoque clásico como desde la óptica bayesiana.This essay reviews some statistical concepts frequently used in public health research that are commonly misinterpreted. These include point estimates, confidence intervals, and hypothesis tests. By comparing them using the classical and the Bayesian perspectives, their interpretation becomes clearer.

  5. Effects and prevalence of nonresponders after 12 weeks of high-intensity interval or resistance training in women with insulin resistance: a randomized trial.

    Science.gov (United States)

    Álvarez, Cristian; Ramírez-Campillo, Rodrigo; Ramírez-Vélez, Robinson; Izquierdo, Mikel

    2017-04-01

    Our aim was to investigate the effects and prevalence of nonresponders (NR) to high-intensity interval training (HIIT) and resistance training (RT) in women with insulin resistance on cardiometabolic health parameters. Sedentary overweight/obese insulin-resistant women (age = 33.5 ± 6.5 yr; body mass index = 29.9 ± 3.7 kg/m 2 ) were randomly assigned to a triweekly HIIT program (HIIT; n = 18) or resistance training (RT; n = 17). Anthropometry (body mass, fat mass, muscle mass, waist circumference, and skinfold thickness), cardiovascular (blood pressure), metabolic [fasting glucose, fasting insulin, and homeostatic model of insulin resistance (HOMA-IR)], as well as muscle strength, and endurance performance covariables were measured before and after 12 wk in both intervention groups. The interindividual variability to exercise training of the subjects was categorized as responders and NR using as cut points two times the typical error of measurement in mean outcomes. After intervention, significant reduction in waist circumference, skinfold thicknesses, fat mass, blood pressure, fasting glucose, insulin, and HOMA-IR ( P training. A uniqueness of the present study was to examine the NR prevalence in women with insulin resistance after high-intensity interval (HIIT) and resistance training (RT). This study demonstrates that 12 wk of HIIT and RT have similar effects and NR prevalence to improve glucose control variables. However, significantly different NR prevalence were observed in other anthropometric, cardiovascular, strength, and endurance performance measurements. Copyright © 2017 the American Physiological Society.

  6. Korean pediatric reference intervals for FT4, TSH, and TPO Ab and the prevalence of thyroid dysfunction: A population-based study.

    Science.gov (United States)

    Lim, Han Hyuk

    2017-12-01

    The appropriate age-related reference intervals for thyroid-stimulating hormone (TSH) and free thyroxine (FT4) are important in interpreting the results of thyroid function tests in children and adolescents. However, these reference intervals are scanty. This study aimed to establish the reference intervals for FT4, TSH, and thyroid peroxidase antibody (TPO Ab), and identify the epidemiological prevalence of thyroid dysfunction in a Korean pediatric population. The data from a sample of 2042 children and adolescents aged 10-18years who underwent a nationwide Korean representative sampling and cross-sectional survey with blood collection for a thyroid function test using an electrochemiluminescence immunoassay were evaluated. Based on the National Academy of Clinical Biochemistry (NACB) criteria, the median and range (2.5th - 97.5th percentile) for FT4 and TSH in total were 16.47pmol/L (12.61-21.49pmol/L) and 2.48mIU/L (0.63-7.03mIU/L), respectively. Positive TPO Ab (3.1%) by NACB was >19.16kIU/L (boys) and >29.30kIU/L (girls) for adolescents aged 10-18years. FT4 and TSH were associated with increasing and decreasing age, respectively. Boys' FT4 and girls' TPO Ab levels were greater than for the other sex, respectively. Using the new reference interval, overt hypothyroidism, subclinical hypothyroidism, subclinical hyperthyroidism, and overt hyperthyroidism were found in 0.5%, 2.1%, 1.3%, and 1.2%, respectively, of Korean children and adolescents. This study provides evidence-based age- and sex-specific reference intervals for thyroid hormones and autoantibodies, and identifies the current prevalence of thyroid dysfunction in a Korean pediatric group. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  7. Deriving confidence in paleointensity estimates

    Science.gov (United States)

    Paterson, Greig A.; Heslop, David; Muxworthy, Adrian R.

    2010-07-01

    Determining the strength of the ancient geomagnetic field (paleointensity) can be time consuming and can result in high data rejection rates. The current paleointensity database is therefore dominated by studies that contain only a small number of paleomagnetic samples (n). It is desirable to estimate how many samples are required to obtain a reliable estimate of the true paleointensity and the uncertainty associated with that estimate. Assuming that real paleointensity data are normally distributed, an assumption adopted by most workers when they employ the arithmetic mean and standard deviation to characterize their data, we can use distribution theory to address this question. Our calculations indicate that if we wish to have 95% confidence that an estimated mean falls within a ±10% interval about the true mean, as many as 24 paleomagnetic samples are required. This is an unfeasibly high number for typical paleointensity studies. Given that most paleointensity studies have small n, this requires that we have adequately defined confidence intervals around estimated means. We demonstrate that the estimated standard deviation is a poor method for defining confidence intervals for n levels, within-site consistency criteria must be depend on n. Defining such a criterion using the 95% confidence level results in the rejection of ˜56% of all currently available paleointensity data entries.

  8. Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance

    Science.gov (United States)

    Álvarez, Cristian; Ramírez-Campillo, Rodrigo; Ramírez-Vélez, Robinson; Izquierdo, Mikel

    2017-01-01

    Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R) or non-responders (NRs), especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT) and the prevalence of NRs in adult women with higher and lower levels of insulin resistance. Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m2; n = 20) and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m2; n = 20). Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training. Results: There were significant training-induced changes [delta percent (Δ%)] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) scores in the H-IR group (−8.8, −26.5, −32.1%, p HOMA-IR (25 vs. 45%, p = 0.185). Conclusion: Independent of the “magnitude” of the cardiometabolic disease (i.e., higher vs. lower insulin resistance), no differences were observed in the NRs prevalence with regard to improved HOMA-IR or to anthropometric, cardiovascular, and muscle performance co-variables after 10 weeks of HIIT in sedentary adult women. This research demonstrates the protective effect of HIIT against cardiometabolic disease progression in a sedentary population. PMID:28729841

  9. Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance.

    Science.gov (United States)

    Álvarez, Cristian; Ramírez-Campillo, Rodrigo; Ramírez-Vélez, Robinson; Izquierdo, Mikel

    2017-01-01

    Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R) or non-responders (NRs), especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT) and the prevalence of NRs in adult women with higher and lower levels of insulin resistance. Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m 2 ; n = 20) and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m 2 ; n = 20). Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training. Results: There were significant training-induced changes [delta percent (Δ%)] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) scores in the H-IR group (-8.8, -26.5, -32.1%, p performance co-variables after 10 weeks of HIIT in sedentary adult women. This research demonstrates the protective effect of HIIT against cardiometabolic disease progression in a sedentary population.

  10. Prevalence

    Directory of Open Access Journals (Sweden)

    Ahmed E. Mansour

    2013-07-01

    Conclusion: The prevalence of spontaneous bacterial pleuritis in the studied group of patients with hepatic hydrothorax was 14.3%. Patients with advanced liver disease, low pleural fluid protein, or SBP are at risk for spontaneous bacterial pleuritis.

  11. Interval Training

    Science.gov (United States)

    Healthy Lifestyle Fitness Interval training can help you get the most out of your workout. By Mayo Clinic Staff Are you ready to shake up ... more time at the gym? Consider aerobic interval training. Once the domain of elite athletes, interval training ...

  12. Statistical intervals a guide for practitioners

    CERN Document Server

    Hahn, Gerald J

    2011-01-01

    Presents a detailed exposition of statistical intervals and emphasizes applications in industry. The discussion differentiates at an elementary level among different kinds of statistical intervals and gives instruction with numerous examples and simple math on how to construct such intervals from sample data. This includes confidence intervals to contain a population percentile, confidence intervals on probability of meeting specified threshold value, and prediction intervals to include observation in a future sample. Also has an appendix containing computer subroutines for nonparametric stati

  13. Confidant Relations in Italy

    Directory of Open Access Journals (Sweden)

    Jenny Isaacs

    2015-02-01

    Full Text Available Confidants are often described as the individuals with whom we choose to disclose personal, intimate matters. The presence of a confidant is associated with both mental and physical health benefits. In this study, 135 Italian adults responded to a structured questionnaire that asked if they had a confidant, and if so, to describe various features of the relationship. The vast majority of participants (91% reported the presence of a confidant and regarded this relationship as personally important, high in mutuality and trust, and involving minimal lying. Confidants were significantly more likely to be of the opposite sex. Participants overall were significantly more likely to choose a spouse or other family member as their confidant, rather than someone outside of the family network. Familial confidants were generally seen as closer, and of greater value, than non-familial confidants. These findings are discussed within the context of Italian culture.

  14. Prevalence

    Directory of Open Access Journals (Sweden)

    Mohammed Al-Darwish

    2014-07-01

    Conclusion: Results indicated that dental caries prevalence among school children in Qatar has reached critical levels, and is influenced by socio-demographic factors. The mean decayed, missing, and filled teeth values obtained in this study were the second highest detected in the Eastern Mediterranean region.

  15. Prevalence of Non-responders for Glucose Control Markers after 10 Weeks of High-Intensity Interval Training in Adult Women with Higher and Lower Insulin Resistance

    Directory of Open Access Journals (Sweden)

    Cristian Álvarez

    2017-07-01

    Full Text Available Background: Exercise training improves performance and biochemical parameters on average, but wide interindividual variability exists, with individuals classified as responders (R or non-responders (NRs, especially between populations with higher or lower levels of insulin resistance. This study assessed the effects of high-intensity interval training (HIIT and the prevalence of NRs in adult women with higher and lower levels of insulin resistance.Methods: Forty adult women were assigned to a HIIT program, and after training were analyzed in two groups; a group with higher insulin resistance (H-IR, 40 ± 6 years; BMI: 29.5 ± 3.7 kg/m2; n = 20 and a group with lower insulin resistance (L-IR, 35 ± 9 years; 27.8 ± 2.8 kg/m2; n = 20. Anthropometric, cardiovascular, metabolic, and performance variables were measured at baseline and after 10 weeks of training.Results: There were significant training-induced changes [delta percent (Δ%] in fasting glucose, fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR scores in the H-IR group (−8.8, −26.5, −32.1%, p < 0.0001, whereas no significant changes were observed in the L-IR. Both groups showed significant pre-post changes in other anthropometric variables [waist circumference (−5.2, p < 0.010, and −3.8%, p = 0.046 and tricipital (−13.3, p < 0.010, and −13.6%, p < 0.0001, supra-iliac (−19.4, p < 0.0001, and −13.6%, p < 0.0001, and abdominal (−18.2, p < 0.0001, and −15.6%, p < 0.010 skinfold measurements]. Systolic blood pressure decreased significantly only in the L-IR group (−3.2%, p < 0.010. Both groups showed significant increases in 1RMLE (+12.9, p < 0.010, and +14.7%, p = 0.045. There were significant differences in the prevalence of NRs between the H-IR and L-IR groups for fasting glucose (25 vs. 95%, p < 0.0001 and fasting insulin (p = 0.025 but not for HOMA-IR (25 vs. 45%, p = 0.185.Conclusion: Independent of the “magnitude” of the

  16. Modified Confidence Intervals for the Mean of an Autoregressive Process.

    Science.gov (United States)

    1985-08-01

    autorregressive method of simulation output analysis. Jow (1982) details the autoregressive method for vector processes, and the articles LAW AND KELTON (1982...moments and cumulants of some function f(z), where z is a vector of sample means of an asymptotically stationary sequence. After expanding f in a Taylor...we may take S(i) = " z and obtain all the analogous results for mixed cumulants provided the vector process ( (’)): i > 0) satisfies the mixing and

  17. Bootstrap confidence intervals for model-based surveys | Ouma ...

    African Journals Online (AJOL)

    To deal with the problem, Chambers and Dorfam (1994) suggested a n alternative method based on the bootstrap methodology. Their method is meant for model-based surveys. It starts by assuming a simple linear regression model as a working model in which the ratio estimator is optimal for estimating the population total.

  18. A quick method to calculate QTL confidence interval

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... observations randomly with replacement from the observed data, and then mapping to detect QTL at ... rate the QTL allele substitution effect and the number of indi- viduals genotyped and phenotyped to .... Knott regression to do QTL analysis with step size of 1 cM scanning. Then CI was calculated with ...

  19. Intervals of confidence: Uncertain accounts of global hunger

    NARCIS (Netherlands)

    Yates-Doerr, E.

    2015-01-01

    Global health policy experts tend to organize hunger through scales of ‘the individual’, ‘the community’ and ‘the global’. This organization configures hunger as a discrete, measurable object to be scaled up or down with mathematical certainty. This article offers a counter to this approach, using

  20. Secure and Usable Bio-Passwords based on Confidence Interval

    OpenAIRE

    Aeyoung Kim; Geunshik Han; Seung-Hyun Seo

    2017-01-01

    The most popular user-authentication method is the password. Many authentication systems try to enhance their security by enforcing a strong password policy, and by using the password as the first factor, something you know, with the second factor being something you have. However, a strong password policy and a multi-factor authentication system can make it harder for a user to remember the password and login in. In this paper a bio-password-based scheme is proposed as a unique authenticatio...

  1. Confidence Intervals for Omega Coefficient: Proposal for Calculus.

    Science.gov (United States)

    Ventura-León, José Luis

    2018-01-01

    La confiabilidad es entendida como una propiedad métrica de las puntuaciones de un instrumento de medida. Recientemente se viene utilizando el coeficiente omega (ω) para la estimación de la confiabilidad. No obstante, la medición nunca es exacta por la influencia del error aleatorio, por esa razón es necesario calcular y reportar el intervalo de confianza (IC) que permite encontrar en valor verdadero en un rango de medida. En ese contexto, el artículo plantea una forma de estimar el IC mediante el método de bootstrap para facilitar este procedimiento se brindan códigos de R (un software de acceso libre) para que puedan realizarse los cálculos de una forma amigable. Se espera que el artículo sirva de ayuda a los investigadores de ámbito de salud.

  2. Large Sample Confidence Intervals for Item Response Theory Reliability Coefficients

    Science.gov (United States)

    Andersson, Björn; Xin, Tao

    2018-01-01

    In applications of item response theory (IRT), an estimate of the reliability of the ability estimates or sum scores is often reported. However, analytical expressions for the standard errors of the estimators of the reliability coefficients are not available in the literature and therefore the variability associated with the estimated reliability…

  3. Interval Training.

    Science.gov (United States)

    President's Council on Physical Fitness and Sports, Washington, DC.

    Regardless of the type of physical activity used, interval training is simply repeated periods of physical stress interspersed with recovery periods during which activity of a reduced intensity is performed. During the recovery periods, the individual usually keeps moving and does not completely recover before the next exercise interval (e.g.,…

  4. Consciousness and confidence.

    Science.gov (United States)

    Rosenthal, David

    2018-02-02

    It is natural to see conscious perceptions as typically bringing with them a degree of confidence about what is perceived. So one might also expect such confidence not to occur if a perception is not conscious. This has resulted in the use of confidence as a test or measure of consciousness, one that may be more reliable and fine-grained than the traditional appeal to subjective report as a test for a perception's being conscious. The following describes theoretical difficulties for the use of confidence as a reliable test for consciousness, which show that confidence is less reliable than subjective report. Difficulties are also presented for the use of confidence ratings in assessing degrees of consciousness, which cast doubt on any advantage confidence might have from being more fine-grained than subjective report. And an explanation is proposed for the wide appeal of using confidence to assess subjective awareness, an explanation that also makes clear why confidence is less reliable than subjective report. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Prevalence of tic disorders: a systematic review and meta-analysis.

    Science.gov (United States)

    Knight, Tristan; Steeves, Thomas; Day, Lundy; Lowerison, Mark; Jette, Nathalie; Pringsheim, Tamara

    2012-08-01

    This study evaluated the prevalence of tic disorders. MEDLINE and EMBASE databases were searched, using terms specific to Tourette syndrome and tic disorders, for studies of incidence, prevalence, and epidemiology. Thirty-five studies reporting data from 1985-2011 on the incidence or prevalence of tic disorders in a defined population were included. One reported incidence, and 34 reported prevalence. Meta-analysis of 13 studies of children yielded a prevalence of Tourette syndrome at 0.77% (95% confidence interval, 0.39-1.51%). Prevalence is higher in boys: 1.06% of boys were affected (95% confidence interval, 0.54-2.09%) vs 0.25% of girls (95% confidence interval, 0.05-1.20%). Transient tic disorder comprised the most common tic disorder in children, affecting 2.99% (95% confidence interval, 1.60-5.61%). Meta-analysis of two studies assessing adults for Tourette syndrome revealed a prevalence of 0.05% (95% confidence interval, 0.03-0.08%). The prevalence of tic disorders was higher in all studies performed in special education populations. Tic disorders are more common in children than adults, in boys than girls, and in special education populations. Parents, educators, healthcare professionals, and administrators should be aware of the frequency with which tic disorders occur, and ensure proper access to appropriate care. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Confidence bounds for nonlinear dose-response relationships

    DEFF Research Database (Denmark)

    Baayen, C; Hougaard, P

    2015-01-01

    . It is well known that Wald confidence intervals are based on linear approximations and are often unsatisfactory in nonlinear models. Apart from incorrect coverage rates, they can be unreasonable in the sense that the lower confidence limit of the difference to placebo can be negative, even when an overall...... test shows a significant positive effect. Bootstrap confidence intervals solve many of the problems of the Wald confidence intervals but are computationally intensive and prone to undercoverage for small sample sizes. In this work, we propose a profile likelihood approach to compute confidence...... intervals for the dose-response curve. These confidence bounds have better coverage than Wald intervals and are more precise and generally faster than bootstrap methods. Moreover, if monotonicity is assumed, the profile likelihood approach takes this automatically into account. The approach is illustrated...

  7. Raising Confident Kids

    Science.gov (United States)

    ... road ahead — a road they can take with confidence. Reviewed by: D'Arcy Lyness, PhD Date reviewed: July 2013 More on this topic for: Parents Kids Teens Developing Your Child's Self-Esteem Help Your Child Get Organized Teaching Your Child ...

  8. Confidence of Today's Youth

    Science.gov (United States)

    Intellect, 1977

    1977-01-01

    Results of a survey by the Gallup Organization, Inc., commissioned by the Miami Valley (Ohio) Young Adult Ministry and released at Wright State University, show that young Americans essentially have confidence in the basic American ideas and institutions, such as organized religion, the future of the U.S., free enterprise, labor unions, business…

  9. interval functions

    Directory of Open Access Journals (Sweden)

    J. A. Chatfield

    1978-01-01

    Full Text Available Suppose N is a Banach space of norm |•| and R is the set of real numbers. All integrals used are of the subdivision-refinement type. The main theorem [Theorem 3] gives a representation of TH where H is a function from R×R to N such that H(p+,p+, H(p,p+, H(p−,p−, and H(p−,p each exist for each p and T is a bounded linear operator on the space of all such functions H. In particular we show that TH=(I∫abfHdα+∑i=1∞[H(xi−1,xi−1+−H(xi−1+,xi−1+]β(xi−1+∑i=1∞[H(xi−,xi−H(xi−,xi−]Θ(xi−1,xiwhere each of α, β, and Θ depend only on T, α is of bounded variation, β and Θ are 0 except at a countable number of points, fH is a function from R to N depending on H and {xi}i=1∞ denotes the points P in [a,b]. for which [H(p,p+−H(p+,p+]≠0 or [H(p−,p−H(p−,p−]≠0. We also define an interior interval function integral and give a relationship between it and the standard interval function integral.

  10. Human Papillomavirus - Prevalence of High-Risk and Low-Risk Types among Females Aged 14-59 Years, National Health and ...

    Science.gov (United States)

    ... Archive Data & Statistics Sexually Transmitted Diseases Figure 45. Human Papillomavirus — Prevalence of High-risk and Low-risk ... on the STD Data and Statistics page . * HPV = human papillomavirus. NOTE: Error bars indicate 95% confidence interval. ...

  11. Comparing the Prevalence of Handedness between Normal and Congenitally Deaf Students in Age Intervals of 12 to 18 Years in Tehran

    Directory of Open Access Journals (Sweden)

    Zahra Jafari

    2007-04-01

    Full Text Available Objective: Handedness is the most prominent behavioral asymmetry in human. The term of hand preference points to prefer hand or functional asymmetry in manual tasks. The items were considered in this study were: the comparison of handedness between normal and congenitally deaf students the effects of age, sex, and pressure on using right hand for unimanual tasks on handedness the frequency of left-handers among student’s families, the influence of hand preference on English language capabilities, and the point of view of people rather to left-handers have been investigated. Materials & Methods: This cross-sectional comparative study was conducted on 760 students including 380 normal students and 380 deaf students with congenital severe or profound sensory-neural hearing loss from 12 to 18 years of age by that were selected purposefully, completing Edinburg handedness inventory in Tehran. The students didn’t have any confirmed diseases or neurological disorders, except hearing loss in deaf student. Data were gathered through the completion of the Edinburg Handedness Inventory by the students. The student’s aural records and also the confirmation of the audiologist in the deaf schools were considered in order to determine the kind and degree of hearing loss. Results: The prevalence of left-handedness among normal (9.7% and deaf (10.3% students were near to each other, and there was no significant difference between them (P=0.901, z=-1.24. The prevalence of left-handedness was higher in boys rather than girls, but there was no significant influence of sex and age on results (P>0.05. The family and/or teacher pressure for using right hand was 16.0% in normal students and 5.0% in deaf students, and they didn’t report any strict pressure or severity regard this mater. The frequency of left-handers was higher among family of normal students (22.6% than deaf students (13.2%, and the difference between them was significant statistically (P=0

  12. Comparison of asymptotic confidence sets for regression in small samples.

    Science.gov (United States)

    Kolobkov, Dmitry; Demin, Oleg; Metelkin, Evgeny

    2016-01-01

    In case of small samples, asymptotic confidence sets may be inaccurate, with their actual coverage probability far from a nominal confidence level. In a single framework, we consider four popular asymptotic methods of confidence estimation. These methods are based on model linearization, F-test, likelihood ratio test, and nonparametric bootstrapping procedure. Next, we apply each of these methods to derive three types of confidence sets: confidence intervals, confidence regions, and pointwise confidence bands. Finally, to estimate the actual coverage of these confidence sets, we conduct a simulation study on three regression problems. A linear model and nonlinear Hill and Gompertz models are tested in conditions of different sample size and experimental noise. The simulation study comprises calculation of the actual coverage of confidence sets over pseudo-experimental datasets for each model. For confidence intervals, such metrics as width and simultaneous coverage are also considered. Our comparison shows that the F-test and linearization methods are the most suitable for the construction of confidence intervals, the F-test - for confidence regions and the linearization - for pointwise confidence bands.

  13. Confidence in Numerical Simulations

    International Nuclear Information System (INIS)

    Hemez, Francois M.

    2015-01-01

    This PowerPoint presentation offers a high-level discussion of uncertainty, confidence and credibility in scientific Modeling and Simulation (M&S). It begins by briefly evoking M&S trends in computational physics and engineering. The first thrust of the discussion is to emphasize that the role of M&S in decision-making is either to support reasoning by similarity or to ''forecast,'' that is, make predictions about the future or extrapolate to settings or environments that cannot be tested experimentally. The second thrust is to explain that M&S-aided decision-making is an exercise in uncertainty management. The three broad classes of uncertainty in computational physics and engineering are variability and randomness, numerical uncertainty and model-form uncertainty. The last part of the discussion addresses how scientists ''think.'' This thought process parallels the scientific method where by a hypothesis is formulated, often accompanied by simplifying assumptions, then, physical experiments and numerical simulations are performed to confirm or reject the hypothesis. ''Confidence'' derives, not just from the levels of training and experience of analysts, but also from the rigor with which these assessments are performed, documented and peer-reviewed.

  14. Confidence bands for inverse regression models

    International Nuclear Information System (INIS)

    Birke, Melanie; Bissantz, Nicolai; Holzmann, Hajo

    2010-01-01

    We construct uniform confidence bands for the regression function in inverse, homoscedastic regression models with convolution-type operators. Here, the convolution is between two non-periodic functions on the whole real line rather than between two periodic functions on a compact interval, since the former situation arguably arises more often in applications. First, following Bickel and Rosenblatt (1973 Ann. Stat. 1 1071–95) we construct asymptotic confidence bands which are based on strong approximations and on a limit theorem for the supremum of a stationary Gaussian process. Further, we propose bootstrap confidence bands based on the residual bootstrap and prove consistency of the bootstrap procedure. A simulation study shows that the bootstrap confidence bands perform reasonably well for moderate sample sizes. Finally, we apply our method to data from a gel electrophoresis experiment with genetically engineered neuronal receptor subunits incubated with rat brain extract

  15. Prevalence of childhood disability in rural KwaZulu Natal | Couper ...

    African Journals Online (AJOL)

    1 000 (95% confidence interval (CI): 71 - 95). The overall confirmed prevalence rate for children with disabilities under 10years was 60/1 000 (95% CI: 50- 71). The most prevalent disabilities were mild perceptual or learning disability (17/1 000) ...

  16. Prevalence of Chlamydophila psittaci in fecal droppings from feral pigeons in Amsterdam, The Netherlands

    NARCIS (Netherlands)

    Heddema, Edou R.; ter Sluis, Sietske; Buys, Jan A.; Vandenbroucke-Grauls, Christina M. J. E.; van Wijnen, Joop H.; Visser, Caroline E.

    2006-01-01

    In many cities, the feral rock dove is an abundant bird species that can harbor Chlamydophila psittaci. We determined the prevalence and genotype of C. psittaci in fresh fecal samples from feral pigeons in Amsterdam, The Netherlands. The prevalence was 7.9% overall (26/331; 95% confidence interval,

  17. Globalization of consumer confidence

    Directory of Open Access Journals (Sweden)

    Çelik Sadullah

    2017-01-01

    Full Text Available The globalization of world economies and the importance of nowcasting analysis have been at the core of the recent literature. Nevertheless, these two strands of research are hardly coupled. This study aims to fill this gap through examining the globalization of the consumer confidence index (CCI by applying conventional and unconventional econometric methods. The US CCI is used as the benchmark in tests of comovement among the CCIs of several developing and developed countries, with the data sets divided into three sub-periods: global liquidity abundance, the Great Recession, and postcrisis. The existence and/or degree of globalization of the CCIs vary according to the period, whereas globalization in the form of coherence and similar paths is observed only during the Great Recession and, surprisingly, stronger in developing/emerging countries.

  18. Interrelation of economic confidence with other types of confidence

    OpenAIRE

    Бонецький, Орест Олегович

    2013-01-01

    The paper gives the object and the subject of the study, which are used as a criterion allowing to separate the economic confidence from other types of confidence. The terms describing the psychological and sociological confidence are proposed. It was found that the economic confidence is interrelated with psychological confidence by motivation and advertising, sociological – by the results of activity of public organizations, state regulation of the economy. On the example of information-com...

  19. Monitoring tigers with confidence.

    Science.gov (United States)

    Linkie, Matthew; Guillera-Arroita, Gurutzeta; Smith, Joseph; Rayan, D Mark

    2010-12-01

    With only 5% of the world's wild tigers (Panthera tigris Linnaeus, 1758) remaining since the last century, conservationists urgently need to know whether or not the management strategies currently being employed are effectively protecting these tigers. This knowledge is contingent on the ability to reliably monitor tiger populations, or subsets, over space and time. In the this paper, we focus on the 2 seminal methodologies (camera trap and occupancy surveys) that have enabled the monitoring of tiger populations with greater confidence. Specifically, we: (i) describe their statistical theory and application in the field; (ii) discuss issues associated with their survey designs and state variable modeling; and, (iii) discuss their future directions. These methods have had an unprecedented influence on increasing statistical rigor within tiger surveys and, also, surveys of other carnivore species. Nevertheless, only 2 published camera trap studies have gone beyond single baseline assessments and actually monitored population trends. For low density tiger populations (e.g. tiger/100 km(2)) obtaining sufficient precision for state variable estimates from camera trapping remains a challenge because of insufficient detection probabilities and/or sample sizes. Occupancy surveys have overcome this problem by redefining the sampling unit (e.g. grid cells and not individual tigers). Current research is focusing on developing spatially explicit capture-mark-recapture models and estimating abundance indices from landscape-scale occupancy surveys, as well as the use of genetic information for identifying and monitoring tigers. The widespread application of these monitoring methods in the field now enables complementary studies on the impact of the different threats to tiger populations and their response to varying management intervention. © 2010 ISZS, Blackwell Publishing and IOZ/CAS.

  20. Prevalence and correlates of gender-based violence among female ...

    African Journals Online (AJOL)

    The overall prevalence of gender-based violence was 58.8% [95% Confidence Interval (CI) = 52.9% to 64.5%]. Specifically, 22.8%, 22.2% and 50.8% of students experienced physical, sexual or emotional violence respectively. Religious affiliation, ethnicity, indigeneship, marital status, campus residence and faculty ...

  1. Prevalence and predictors of institutional delivery among pregnant ...

    African Journals Online (AJOL)

    ebutamanya

    2015-05-25

    May 25, 2015 ... in a year with contraceptive use coverage of 15% in 2012 (Regional. Annual Reproductive and Child Health Report). Sampling and data collection. Using the formula Z2p(100-p)/e2, the marginal error (e) of 5%, z at. 95% confidence interval of 1.96, and prevalence (p) of institution delivery of 46%, we ...

  2. Prevalence and determinants of Helicobacter pylori infection in preschool children

    DEFF Research Database (Denmark)

    Rothenbacher, D; Bode, G; Berg, Gabriele

    1998-01-01

    .4%) were infected with H. pylori. Nationality, place of residence in the first year of life and duration of living in Germany were strongly associated with H. pylori infection status. The prevalence varied from 4.8% (95% confidence interval [CI]: 3.3-6.8%) in children with German nationality who were born...

  3. Prevalence of multiple sclerosis in Denmark 1950-2005

    DEFF Research Database (Denmark)

    Bentzen, Joan; Meulengracht Flachs, Esben; Stenager, Egon

    2010-01-01

    Multiple sclerosis is an inflammatory disease of the central nervous system of unknown aetiology. Its prevalence varies by ethnicity and place: persons of northern European descent are at increased risk while persons living at lower latitudes appear to be protected against the disease. The Danish...... Multiple Sclerosis Registry is a national registry established in 1956 after a population-based survey which receives information from numerous sources. It is considered to be more than 90% complete, with a validity of 94%. Using data from the Registry, we calculated prevalences per 100,000 inhabitants....... The standardized prevalence of multiple sclerosis increased from 58.8 (95% confidence interval: 54.9-62.7) in 1950 to 154.5 per 100,000 (95% confidence interval: 148.8-160.2) in 2005, and the female to male ratio increased from 1.31 in 1950 to 2.02 in 2005. The increase in prevalence is due to both increased...

  4. Confidence bounds for normal and lognormal distribution coefficients of variation

    Science.gov (United States)

    Steve Verrill

    2003-01-01

    This paper compares the so-called exact approach for obtaining confidence intervals on normal distribution coefficients of variation to approximate methods. Approximate approaches were found to perform less well than the exact approach for large coefficients of variation and small sample sizes. Web-based computer programs are described for calculating confidence...

  5. High prevalence of refractive errors in a rural population: 'Nooravaran Salamat' Mobile Eye Clinic experience.

    Science.gov (United States)

    Hashemi, Hassan; Rezvan, Farhad; Ostadimoghaddam, Hadi; Abdollahi, Majid; Hashemi, Maryam; Khabazkhoob, Mehdi

    2013-01-01

    The prevalence of myopia and hyperopia and determinants were determined in a rural population of Iran. Population-based cross-sectional study. Using random cluster sampling, 13 of the 83 villages of Khaf County in the north east of Iran were selected. Data from 2001 people over the age of 15 years were analysed. Visual acuity measurement, non-cycloplegic refraction and eye examinations were done at the Mobile Eye Clinic. The prevalence of myopia and hyperopia based on spherical equivalent worse than -0.5 dioptre and +0.5 dioptre, respectively. The prevalence of myopia, hyperopia and anisometropia in the total study sample was 28% (95% confidence interval: 25.9-30.2), 19.2% (95% confidence interval: 17.3-21.1), and 11.5% (95% confidence interval: 10.0-13.1), respectively. In the over 40 population, the prevalence of myopia and hyperopia was 32.5% (95% confidence interval: 28.9-36.1) and 27.9% (95% confidence interval: 24.5-31.3), respectively. In the multiple regression model for this group, myopia strongly correlated with cataract (odds ratio = 1.98 and 95% confidence interval: 1.33-2.93), and hyperopia only correlated with age (P < 0.001). The prevalence of high myopia and high hyperopia was 1.5% and 4.6%. In the multiple regression model, anisometropia significantly correlated with age (odds ratio = 1.04) and cataract (odds ratio = 5.2) (P < 0.001). The prevalence of myopia and anisometropia was higher than that in previous studies in urban population of Iran, especially in the elderly. Cataract was the only variable that correlated with myopia and anisometropia. © 2013 The Authors. Clinical and Experimental Ophthalmology © 2013 Royal Australian and New Zealand College of Ophthalmologists.

  6. The idiosyncratic nature of confidence

    Science.gov (United States)

    Navajas, Joaquin; Hindocha, Chandni; Foda, Hebah; Keramati, Mehdi; Latham, Peter E; Bahrami, Bahador

    2017-01-01

    Confidence is the ‘feeling of knowing’ that accompanies decision making. Bayesian theory proposes that confidence is a function solely of the perceived probability of being correct. Empirical research has suggested, however, that different individuals may perform different computations to estimate confidence from uncertain evidence. To test this hypothesis, we collected confidence reports in a task where subjects made categorical decisions about the mean of a sequence. We found that for most individuals, confidence did indeed reflect the perceived probability of being correct. However, in approximately half of them, confidence also reflected a different probabilistic quantity: the perceived uncertainty in the estimated variable. We found that the contribution of both quantities was stable over weeks. We also observed that the influence of the perceived probability of being correct was stable across two tasks, one perceptual and one cognitive. Overall, our findings provide a computational interpretation of individual differences in human confidence. PMID:29152591

  7. The idiosyncratic nature of confidence.

    Science.gov (United States)

    Navajas, Joaquin; Hindocha, Chandni; Foda, Hebah; Keramati, Mehdi; Latham, Peter E; Bahrami, Bahador

    2017-11-01

    Confidence is the 'feeling of knowing' that accompanies decision making. Bayesian theory proposes that confidence is a function solely of the perceived probability of being correct. Empirical research has suggested, however, that different individuals may perform different computations to estimate confidence from uncertain evidence. To test this hypothesis, we collected confidence reports in a task where subjects made categorical decisions about the mean of a sequence. We found that for most individuals, confidence did indeed reflect the perceived probability of being correct. However, in approximately half of them, confidence also reflected a different probabilistic quantity: the perceived uncertainty in the estimated variable. We found that the contribution of both quantities was stable over weeks. We also observed that the influence of the perceived probability of being correct was stable across two tasks, one perceptual and one cognitive. Overall, our findings provide a computational interpretation of individual differences in human confidence.

  8. Hirschsprung's disease prevalence in Europe. A register based study

    DEFF Research Database (Denmark)

    Best, Kate E; Addor, Marie-Claude; Arriola, Larraitz

    2014-01-01

    BACKGROUND: Hirschsprung's disease is a congenital gut motility disorder, characterised by the absence of the enteric ganglion cells along the distal gut. The aim of this study was to describe the epidemiology of Hirschsprung's disease, including additional congenital anomalies, total prevalence......, trends, and association with maternal age. METHODS: Cases of Hirschsprung's disease delivered during 1980 to 2009 notified to 31 European Surveillance of Congenital Anomaly registers formed the population-based case-series. Prevalence rates and 95% confidence intervals were calculated as the number...... interval, 1.03-1.15) per 10,000 births and there was a small but significant increase in prevalence over time (relative risk = 1.01; 95% credible interval, 1.00-1.02; p = 0.004). There was evidence of geographical heterogeneity in prevalence (p chromosomal...

  9. Graphical interpretation of confidence curves in rankit plots

    DEFF Research Database (Denmark)

    Hyltoft Petersen, Per; Blaabjerg, Ole; Andersen, Marianne

    2004-01-01

    A well-known transformation from the bell-shaped Gaussian (normal) curve to a straight line in the rankit plot is investigated, and a tool for evaluation of the distribution of reference groups is presented. It is based on the confidence intervals for percentiles of the calculated Gaussian...... will fit to the straight line describing the calculated In-Gaussian distribution. The quality of the fit is evaluated by adding confidence intervals (CI) to each point on the line and calculating the percentage of points outside the hyperbola-like CI-curves. The assumption was that the 95% confidence...

  10. Alcohol consumption during pregnancy: prevalence and provider assessment.

    Science.gov (United States)

    Cheng, Diana; Kettinger, Laurie; Uduhiri, Kelechi; Hurt, Lee

    2011-02-01

    To estimate the prevalence of prenatal alcohol consumption and the extent of provider screening and discussion about alcohol use during pregnancy. Data were obtained from a stratified random sample of 12,611 mothers from Maryland who delivered live infants during the years 2001-2008 and completed the Maryland Pregnancy Risk Assessment Monitoring System survey. Analyses were conducted using Proc Surveyfreq in SAS 9.2. Nearly 8% (95% confidence interval 7.1-8.4) of mothers from Maryland reported alcohol consumption during the last 3 months of pregnancy. The highest prevalence of late-pregnancy alcohol consumption was reported by mothers who were non-Hispanic white, (10.9%, confidence interval 9.8-11.9), aged 35 years or older (13.4%, confidence interval 12.4-14.4), and college graduates (11.4%, confidence interval 10.2-12.6) (Pmothers reported that their prenatal care provider did not ask whether they were drinking alcoholic beverages, and 30% (confidence interval 28.3-30.8) reported that a healthcare provider did not counsel them about the consequences of alcohol use on the child. Reported screening and counseling were least prevalent among mothers who were non-Hispanic white, aged 35 years or older, and college graduates (P<.01). Despite the substantial number of women who continue to drink alcohol during pregnancy, healthcare providers do not routinely assess alcohol consumption or counsel all women about its harmful effects. Counseling was least prevalent among the same groups of women with the highest rates for drinking. Provider alcohol assessment, as recommended by the U.S. Surgeon General to prevent alcohol misuse, needs further promotion as a routine part of prenatal care. III.

  11. Predicting confidence in flashbulb memories.

    Science.gov (United States)

    Day, Martin V; Ross, Michael

    2014-01-01

    Years after a shocking news event many people confidently report details of their flashbulb memories (e.g., what they were doing). People's confidence is a defining feature of their flashbulb memories, but it is not well understood. We tested a model that predicted confidence in flashbulb memories. In particular we examined whether people's social bond with the target of a news event predicts confidence. At a first session shortly after the death of Michael Jackson participants reported their sense of attachment to Michael Jackson, as well as their flashbulb memories and emotional and other reactions to Jackson's death. At a second session approximately 18 months later they reported their flashbulb memories and confidence in those memories. Results supported our proposed model. A stronger sense of attachment to Jackson was related to reports of more initial surprise, emotion, and rehearsal during the first session. Participants' bond with Michael Jackson predicted their confidence but not the consistency of their flashbulb memories 18 months later. We also examined whether participants' initial forecasts regarding the persistence of their flashbulb memories predicted the durability of their memories. Participants' initial forecasts were more strongly related to participants' subsequent confidence than to the actual consistency of their memories.

  12. Combining one-sample confidence procedures for inference in the two-sample case.

    Science.gov (United States)

    Fay, Michael P; Proschan, Michael A; Brittain, Erica

    2015-03-01

    We present a simple general method for combining two one-sample confidence procedures to obtain inferences in the two-sample problem. Some applications give striking connections to established methods; for example, combining exact binomial confidence procedures gives new confidence intervals on the difference or ratio of proportions that match inferences using Fisher's exact test, and numeric studies show the associated confidence intervals bound the type I error rate. Combining exact one-sample Poisson confidence procedures recreates standard confidence intervals on the ratio, and introduces new ones for the difference. Combining confidence procedures associated with one-sample t-tests recreates the Behrens-Fisher intervals. Other applications provide new confidence intervals with fewer assumptions than previously needed. For example, the method creates new confidence intervals on the difference in medians that do not require shift and continuity assumptions. We create a new confidence interval for the difference between two survival distributions at a fixed time point when there is independent censoring by combining the recently developed beta product confidence procedure for each single sample. The resulting interval is designed to guarantee coverage regardless of sample size or censoring distribution, and produces equivalent inferences to Fisher's exact test when there is no censoring. We show theoretically that when combining intervals asymptotically equivalent to normal intervals, our method has asymptotically accurate coverage. Importantly, all situations studied suggest guaranteed nominal coverage for our new interval whenever the original confidence procedures themselves guarantee coverage. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  13. Convex Interval Games

    NARCIS (Netherlands)

    Alparslan-Gok, S.Z.; Brânzei, R.; Tijs, S.H.

    2008-01-01

    In this paper, convex interval games are introduced and some characterizations are given. Some economic situations leading to convex interval games are discussed. The Weber set and the Shapley value are defined for a suitable class of interval games and their relations with the interval core for

  14. Cooperative interval games

    OpenAIRE

    Bok, Jan

    2014-01-01

    In this thesis, we study cooperative interval games, a generalized model of cooperative games in which worth of every coalition corresponds with a closed interval representing all possible outcomes of their cooperation. We give a brief introduction into classical cooperative games, interval analysis and finally introduction to cooperative interval games with focus on selections, that is on all possible outcomes of interval game with no additional uncertainty. We introduce new selection-based ...

  15. Professional confidence: a concept analysis.

    Science.gov (United States)

    Holland, Kathlyn; Middleton, Lyn; Uys, Leana

    2012-03-01

    Professional confidence is a concept that is frequently used and or implied in occupational therapy literature, but often without specifying its meaning. Rodgers's Model of Concept Analysis was used to analyse the term "professional confidence". Published research obtained from a federated search in four health sciences databases was used to inform the concept analysis. The definitions, attributes, antecedents, and consequences of professional confidence as evidenced in the literature are discussed. Surrogate terms and related concepts are identified, and a model case of the concept provided. Based on the analysis, professional confidence can be described as a dynamic, maturing personal belief held by a professional or student. This includes an understanding of and a belief in the role, scope of practice, and significance of the profession, and is based on their capacity to competently fulfil these expectations, fostered through a process of affirming experiences. Developing and fostering professional confidence should be nurtured and valued to the same extent as professional competence, as the former underpins the latter, and both are linked to professional identity.

  16. The prevalence of diagnosed tourette syndrome in Canada: A national population-based study.

    Science.gov (United States)

    Yang, Jaeun; Hirsch, Lauren; Martino, Davide; Jette, Nathalie; Roberts, Jodie; Pringsheim, Tamara

    2016-11-01

    The objective of this study was to examine: (1) the prevalence of diagnosed Tourette syndrome in Canada by sex in youth (aged 12-17) and adults and (2) socioeconomic factors in this population. The majority of epidemiological studies of tics have focused on children and youth, with few studies describing the prevalence of tics in adult populations. Canadian data on Tourette syndrome prevalence were derived from the Canadian Community Health Survey 2010 and 2011 cycles, a Statistics Canada population-based cross-sectional survey that collects information related to health status. We determined the prevalence of diagnosed Tourette syndrome and examined sociodemographic factors, including age, sex, education, income, employment, and birthplace. Overall, 122,884 Canadians participated in the surveys, with 122 participants diagnosed with Tourette syndrome. The prevalence of Tourette syndrome was higher in males in youth: 6.03 per 1000 (95% confidence interval: 3.24-8.81) in males versus 0.48 per 1,000 (95% confidence interval: 0.05-0.91) in females, with a prevalence risk ratio of 5.31 (95% confidence interval: 2.38-11.81). In adults, the prevalence of Tourette syndrome was 0.89 per 1,000 (95% confidence interval: 0.48-1.29) in males versus 0.44 (95% confidence interval: 0.16.0-0.71) in females, with a prevalence risk ratio of 1.93 (95% confidence interval: 1.21-3.08). After adjusting for age and sex, adults with Tourette syndrome had lower odds of receiving postsecondary education or being employed and higher odds of having income lower than the median and receiving governmental support. Data on the prevalence of Tourette syndrome in adults are scarce because most studies focus on children. Our data demonstrate a decreasing prevalence risk ratio for sex in adults compared to children. A diagnosis of Tourette syndrome is associated with lower education, income, and employment in adulthood. © 2016 International Parkinson and Movement Disorder Society. © 2016

  17. Targeting Low Career Confidence Using the Career Planning Confidence Scale

    Science.gov (United States)

    McAuliffe, Garrett; Jurgens, Jill C.; Pickering, Worth; Calliotte, James; Macera, Anthony; Zerwas, Steven

    2006-01-01

    The authors describe the development and validation of a test of career planning confidence that makes possible the targeting of specific problem issues in employment counseling. The scale, developed using a rational process and the authors' experience with clients, was tested for criterion-related validity against 2 other measures. The scale…

  18. Optimal prediction intervals of wind power generation

    DEFF Research Database (Denmark)

    Wan, Can; Wu, Zhao; Pinson, Pierre

    2014-01-01

    direct optimization of both the coverage probability and sharpness to ensure the quality. The proposed method does not involve the statistical inference or distribution assumption of forecasting errors needed in most existing methods. Case studies using real wind farm data from Australia have been...... penetration beforehand. This paper proposes a novel hybrid intelligent algorithm approach to directly formulate optimal prediction intervals of wind power generation based on extreme learning machine and particle swarm optimization. Prediction intervals with Associated confidence levels are generated through...

  19. Normal probability plots with confidence.

    Science.gov (United States)

    Chantarangsi, Wanpen; Liu, Wei; Bretz, Frank; Kiatsupaibul, Seksan; Hayter, Anthony J; Wan, Fang

    2015-01-01

    Normal probability plots are widely used as a statistical tool for assessing whether an observed simple random sample is drawn from a normally distributed population. The users, however, have to judge subjectively, if no objective rule is provided, whether the plotted points fall close to a straight line. In this paper, we focus on how a normal probability plot can be augmented by intervals for all the points so that, if the population distribution is normal, then all the points should fall into the corresponding intervals simultaneously with probability 1-α. These simultaneous 1-α probability intervals provide therefore an objective mean to judge whether the plotted points fall close to the straight line: the plotted points fall close to the straight line if and only if all the points fall into the corresponding intervals. The powers of several normal probability plot based (graphical) tests and the most popular nongraphical Anderson-Darling and Shapiro-Wilk tests are compared by simulation. Based on this comparison, recommendations are given in Section 3 on which graphical tests should be used in what circumstances. An example is provided to illustrate the methods. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Alan Greenspan, the confidence strategy

    Directory of Open Access Journals (Sweden)

    Edwin Le Heron

    2006-12-01

    Full Text Available To evaluate the Greenspan era, we nevertheless need to address three questions: Is his success due to talent or just luck? Does he have a system of monetary policy or is he himself the system? What will be his legacy? Greenspan was certainly lucky, but he was also clairvoyant. Above all, he has developed a profoundly original monetary policy. His confidence strategy is clearly opposed to the credibility strategy developed in central banks and the academic milieu after 1980, but also inflation targeting, which today constitutes the mainstream monetary policy regime. The question of his legacy seems more nuanced. However, Greenspan will remain 'for a considerable period of time' a highly heterodox and original central banker. His political vision, his perception of an uncertain world, his pragmatism and his openness form the structure of a powerful alternative system, the confidence strategy, which will leave its mark on the history of monetary policy.

  1. Confidence-Based Feature Acquisition

    Science.gov (United States)

    Wagstaff, Kiri L.; desJardins, Marie; MacGlashan, James

    2010-01-01

    Confidence-based Feature Acquisition (CFA) is a novel, supervised learning method for acquiring missing feature values when there is missing data at both training (learning) and test (deployment) time. To train a machine learning classifier, data is encoded with a series of input features describing each item. In some applications, the training data may have missing values for some of the features, which can be acquired at a given cost. A relevant JPL example is that of the Mars rover exploration in which the features are obtained from a variety of different instruments, with different power consumption and integration time costs. The challenge is to decide which features will lead to increased classification performance and are therefore worth acquiring (paying the cost). To solve this problem, CFA, which is made up of two algorithms (CFA-train and CFA-predict), has been designed to greedily minimize total acquisition cost (during training and testing) while aiming for a specific accuracy level (specified as a confidence threshold). With this method, it is assumed that there is a nonempty subset of features that are free; that is, every instance in the data set includes these features initially for zero cost. It is also assumed that the feature acquisition (FA) cost associated with each feature is known in advance, and that the FA cost for a given feature is the same for all instances. Finally, CFA requires that the base-level classifiers produce not only a classification, but also a confidence (or posterior probability).

  2. Addressing the vaccine confidence gap.

    Science.gov (United States)

    Larson, Heidi J; Cooper, Louis Z; Eskola, Juhani; Katz, Samuel L; Ratzan, Scott

    2011-08-06

    Vaccines--often lauded as one of the greatest public health interventions--are losing public confidence. Some vaccine experts have referred to this decline in confidence as a crisis. We discuss some of the characteristics of the changing global environment that are contributing to increased public questioning of vaccines, and outline some of the specific determinants of public trust. Public decision making related to vaccine acceptance is neither driven by scientific nor economic evidence alone, but is also driven by a mix of psychological, sociocultural, and political factors, all of which need to be understood and taken into account by policy and other decision makers. Public trust in vaccines is highly variable and building trust depends on understanding perceptions of vaccines and vaccine risks, historical experiences, religious or political affiliations, and socioeconomic status. Although provision of accurate, scientifically based evidence on the risk-benefit ratios of vaccines is crucial, it is not enough to redress the gap between current levels of public confidence in vaccines and levels of trust needed to ensure adequate and sustained vaccine coverage. We call for more research not just on individual determinants of public trust, but on what mix of factors are most likely to sustain public trust. The vaccine community demands rigorous evidence on vaccine efficacy and safety and technical and operational feasibility when introducing a new vaccine, but has been negligent in demanding equally rigorous research to understand the psychological, social, and political factors that affect public trust in vaccines. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Interval Temporal Logics

    DEFF Research Database (Denmark)

    Monica, Dario Della; Goranko, Valentin; Montanari, Angelo

    2011-01-01

    We discuss a family of modal logics for reasoning about relational structures of intervals over (usually) linear orders, with modal operators associated with the various binary relations between such intervals, known as Allen’s interval relations. The formulae of these logics are evaluated...... at intervals rather than points and the main eect of that semantic feature is substantially higher expressiveness and computational complexity of the interval logics as compared to point-based ones. Without purporting to provide a comprehensive survey of the field, we take the reader to a journey through...... the main developments in it over the past 10 years and outline some landmark results on expressiveness and (un)decidability of the satisfiability problem for the family of interval logics....

  4. The Great Recession and confidence in homeownership

    OpenAIRE

    Anat Bracha; Julian Jamison

    2013-01-01

    Confidence in homeownership shifts for those who personally experienced real estate loss during the Great Recession. Older Americans are confident in the value of homeownership. Younger Americans are less confident.

  5. Workshop on confidence limits. Proceedings

    International Nuclear Information System (INIS)

    James, F.; Lyons, L.; Perrin, Y.

    2000-01-01

    The First Workshop on Confidence Limits was held at CERN on 17-18 January 2000. It was devoted to the problem of setting confidence limits in difficult cases: number of observed events is small or zero, background is larger than signal, background not well known, and measurements near a physical boundary. Among the many examples in high-energy physics are searches for the Higgs, searches for neutrino oscillations, B s mixing, SUSY, compositeness, neutrino masses, and dark matter. Several different methods are on the market: the CL s methods used by the LEP Higgs searches; Bayesian methods; Feldman-Cousins and modifications thereof; empirical and combined methods. The Workshop generated considerable interest, and attendance was finally limited by the seating capacity of the CERN Council Chamber where all the sessions took place. These proceedings contain all the papers presented, as well as the full text of the discussions after each paper and of course the last session which was a discussion session. The list of participants and the 'required reading', which was expected to be part of the prior knowledge of all participants, are also included. (orig.)

  6. Estimating duration intervals

    NARCIS (Netherlands)

    Ph.H.B.F. Franses (Philip Hans); B.L.K. Vroomen (Björn)

    2003-01-01

    textabstractDuration intervals measure the dynamic impact of advertising on sales. More precise, the p per cent duration interval measures the time lag between the advertising impulse and the moment that p per cent of its effect has decayed. In this paper, we derive an expression for the duration

  7. Confidence scores for prediction models

    DEFF Research Database (Denmark)

    Gerds, Thomas Alexander; van de Wiel, MA

    2011-01-01

    In medical statistics, many alternative strategies are available for building a prediction model based on training data. Prediction models are routinely compared by means of their prediction performance in independent validation data. If only one data set is available for training and validation......, then rival strategies can still be compared based on repeated bootstraps of the same data. Often, however, the overall performance of rival strategies is similar and it is thus difficult to decide for one model. Here, we investigate the variability of the prediction models that results when the same...... to distinguish rival prediction models with similar prediction performances. Furthermore, on the subject level a confidence score may provide useful supplementary information for new patients who want to base a medical decision on predicted risk. The ideas are illustrated and discussed using data from cancer...

  8. Knowledge, Self Confidence and Courage

    DEFF Research Database (Denmark)

    Selberg, Hanne; Steenberg Holtzmann, Jette; Hovedskov, Jette

    Knowledge, self confidence and courage – long lasting learning outcomes through simulation in a clinical context. Hanne Selberg1, Jette Hovedskov2, Jette Steenberg Holtzmann2 The significance and methodology of the researchThe study focuses on simulation alongside the clinical practice and linked....... Results The students identified their major learning outcomes as transfer of operational skills, experiencing self-efficacy and enhanced understanding of the patients' perspective.Involving simulated patients in the training of technical skills contributed to the development of the students' communication...... in a safe and appreciative learning environment.The project has been evaluated in a formative design using a triangulation of questionnaires, field observations, focus group interviews and document reviews. This allowed for a continuously adjustment to the clinical context and the needs of the students...

  9. Doubly Bayesian Analysis of Confidence in Perceptual Decision-Making

    Science.gov (United States)

    Bahrami, Bahador; Latham, Peter E.

    2015-01-01

    Humans stand out from other animals in that they are able to explicitly report on the reliability of their internal operations. This ability, which is known as metacognition, is typically studied by asking people to report their confidence in the correctness of some decision. However, the computations underlying confidence reports remain unclear. In this paper, we present a fully Bayesian method for directly comparing models of confidence. Using a visual two-interval forced-choice task, we tested whether confidence reports reflect heuristic computations (e.g. the magnitude of sensory data) or Bayes optimal ones (i.e. how likely a decision is to be correct given the sensory data). In a standard design in which subjects were first asked to make a decision, and only then gave their confidence, subjects were mostly Bayes optimal. In contrast, in a less-commonly used design in which subjects indicated their confidence and decision simultaneously, they were roughly equally likely to use the Bayes optimal strategy or to use a heuristic but suboptimal strategy. Our results suggest that, while people’s confidence reports can reflect Bayes optimal computations, even a small unusual twist or additional element of complexity can prevent optimality. PMID:26517475

  10. Confidence in ASCI scientific simulations

    Energy Technology Data Exchange (ETDEWEB)

    Ang, J.A.; Trucano, T.G. [Sandia National Labs., Albuquerque, NM (United States); Luginbuhl, D.R. [Dept. of Energy, Washington, DC (United States)

    1998-06-01

    The US Department of Energy`s (DOE) Accelerated Strategic Computing Initiative (ASCI) program calls for the development of high end computing and advanced application simulations as one component of a program to eliminate reliance upon nuclear testing in the US nuclear weapons program. This paper presents results from the ASCI program`s examination of needs for focused validation and verification (V and V). These V and V activities will ensure that 100 TeraOP-scale ASCI simulation code development projects apply the appropriate means to achieve high confidence in the use of simulations for stockpile assessment and certification. The authors begin with an examination of the roles for model development and validation in the traditional scientific method. The traditional view is that the scientific method has two foundations, experimental and theoretical. While the traditional scientific method does not acknowledge the role for computing and simulation, this examination establishes a foundation for the extension of the traditional processes to include verification and scientific software development that results in the notional framework known as Sargent`s Framework. This framework elucidates the relationships between the processes of scientific model development, computational model verification and simulation validation. This paper presents a discussion of the methodologies and practices that the ASCI program will use to establish confidence in large-scale scientific simulations. While the effort for a focused program in V and V is just getting started, the ASCI program has been underway for a couple of years. The authors discuss some V and V activities and preliminary results from the ALEGRA simulation code that is under development for ASCI. The breadth of physical phenomena and the advanced computational algorithms that are employed by ALEGRA make it a subject for V and V that should typify what is required for many ASCI simulations.

  11. Prevalence of Central Obesity among Adults with Normal BMI and Its Association with Metabolic Diseases in Northeast China

    OpenAIRE

    Zhang, Peng; Wang, Rui; Gao, Chunshi; Jiang, Lingling; Lv, Xin; Song, Yuanyuan; Li, Bo

    2016-01-01

    Objectives The present study aimed to investigate the prevalence of central obesity among adults with normal BMI and its association with metabolic diseases in Jilin Province, China. Methods A population-based cross-sectional study was conducted in 2012 in Jilin Province of China. Information was collected by face to face interview. Descriptive data analysis and 95% confidence intervals (CI) of prevalence/frequency were conducted. Log-binomial regression analyses were used to find the indepen...

  12. Confidence limits for parameters of Poisson and binomial distributions

    International Nuclear Information System (INIS)

    Arnett, L.M.

    1976-04-01

    The confidence limits for the frequency in a Poisson process and for the proportion of successes in a binomial process were calculated and tabulated for the situations in which the observed values of the frequency or proportion and an a priori distribution of these parameters are available. Methods are used that produce limits with exactly the stated confidence levels. The confidence interval [a,b] is calculated so that Pr [a less than or equal to lambda less than or equal to b c,μ], where c is the observed value of the parameter, and μ is the a priori hypothesis of the distribution of this parameter. A Bayesian type analysis is used. The intervals calculated are narrower and appreciably different from results, known to be conservative, that are often used in problems of this type. Pearson and Hartley recognized the characteristics of their methods and contemplated that exact methods could someday be used. The calculation of the exact intervals requires involved numerical analyses readily implemented only on digital computers not available to Pearson and Hartley. A Monte Carlo experiment was conducted to verify a selected interval from those calculated. This numerical experiment confirmed the results of the analytical methods and the prediction of Pearson and Hartley that their published tables give conservative results

  13. Prevalence of 35delG and Met34Thr GJB2 variants in Portuguese samples.

    Science.gov (United States)

    Dória, Mariana; Neto, Ana Paula; Santos, Ana Cristina; Barros, Henrique; Fernandes, Susana; Moura, Carla Pinto

    2015-12-01

    To estimate the prevalence of 35delG and Met34Thr variants in a Portuguese children's community sample and to compare these frequencies with nonsyndromic hearing-loss patients. 502 children were randomly selected among the 8647 participants of the Portuguese birth cohort Generation XXI, and screened for Met34Thr and 35delG variants in the GJB2 gene. These variants were also studied on 89 index-cases, observed in the Clinic of "Hereditary Hearing-loss" in Saint John's Hospital Center, presenting a mild to profound nonsyndromic hearing-loss. Among the 502 children from Generation XXI, 10 were heterozygous for the 35delG variant (95% Confidence Interval 1.03-3.68) and 1 homozygous (95% Confidence Interval 0.01-1.24). Other 10 children presented heterozygosity for the Met34Thr variant (95% Confidence Interval 1.03-3.68). No homozygous for the Met34Thr or compound heterozygotes (35delG/Met34Thr) were found. In the total of 89 nonsyndromic hearing-loss patients, 5 (95% Confidence Interval 2.11-12.8) were heterozygous and 7 (95% Confidence Interval 3.61-15.6) were homozygous for the 35delG variant. The Met34Thr variant was found in 4 patients, 2 heterozygous (95% Confidence Interval 0.13-8.31) and 2 homozygous (95% Confidence Interval 0.13-8.31). The carrier frequency of 35delG and Met34Thr variants in a Portuguese sample was 1 in 50. Our data suggests that the 35delG mutation has an association with deafness. For the Met34Thr variant, no association was observed. However, Met34Thr seemed to conform to an additive model in hearing-loss. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Does education explain ethnic differences in myopia prevalence? A population-based study of young adult males in Singapore.

    Science.gov (United States)

    Wu, H M; Seet, B; Yap, E P; Saw, S M; Lim, T H; Chia, K S

    2001-04-01

    To study interethnic variation in myopia prevalence and severity in young adult males in Singapore and to determine whether these variations are related to differences in education level. A population-based survey of refractive errors in a cohort of 15,095 military conscripts between July 1996 and June 1997 using noncycloplegic autorefraction and a standard questionnaire. Prevalence rates of myopia (education level. Singapore has one of the highest prevalences of myopia (79.3%) and severe myopia (13.1%), with Chinese having higher rates (82.2%, 95% confidence interval 81.5, 82.9) compared with Indians (68.7%, 95% confidence interval 65.1, 67.1) and Malays (65.0%, 95% confidence interval 62.9, 67.1). Education was strongly associated with prevalence and severity of myopia. However, significant interethnic variation persisted after adjusting for education. There is a high prevalence of myopia in Singapore. Although prevalence and severity of myopia were strongly associated with education, interethnic variation observed was not fully explained by differences in education level.

  15. Exact Soft Confidence-Weighted Learning

    OpenAIRE

    Wang, Jialei; Zhao, Peilin; Hoi, Steven C. H.

    2012-01-01

    In this paper, we propose a new Soft Confidence-Weighted (SCW) online learning scheme, which enables the conventional confidence-weighted learning method to handle non-separable cases. Unlike the previous confidence-weighted learning algorithms, the proposed soft confidence-weighted learning method enjoys all the four salient properties: (i) large margin training, (ii) confidence weighting, (iii) capability to handle non-separable data, and (iv) adaptive margin. Our experimental results show ...

  16. Confidence building in safety assessments

    International Nuclear Information System (INIS)

    Grundfelt, Bertil

    1999-01-01

    Future generations should be adequately protected from damage caused by the present disposal of radioactive waste. This presentation discusses the core of safety and performance assessment: The demonstration and building of confidence that the disposal system meets the safety requirements stipulated by society. The major difficulty is to deal with risks in the very long time perspective of the thousands of years during which the waste is hazardous. Concern about these problems has stimulated the development of the safety assessment discipline. The presentation concentrates on two of the elements of safety assessment: (1) Uncertainty and sensitivity analysis, and (2) validation and review. Uncertainty is associated both with respect to what is the proper conceptual model and with respect to parameter values for a given model. A special kind of uncertainty derives from the variation of a property in space. Geostatistics is one approach to handling spatial variability. The simplest way of doing a sensitivity analysis is to offset the model parameters one by one and observe how the model output changes. The validity of the models and data used to make predictions is central to the credibility of safety assessments for radioactive waste repositories. There are several definitions of model validation. The presentation discusses it as a process and highlights some aspects of validation methodologies

  17. Prevalence of Sarcoptes scabiei Infection in Pet Dogs in Southern China

    OpenAIRE

    Chen, Yi-Zhou; Liu, Guo-Hua; Song, Hui-Qun; Lin, Rui-Qing; Weng, Ya-Biao; Zhu, Xing-Quan

    2014-01-01

    Little is known about the prevalence of Sarcoptes scabiei infection in pet dogs in China. In the present study, the prevalence of S. scabiei infection in pet dogs in Guangzhou, southern China, was investigated between January and December, 2009. A total of 3,977 pet dogs admitted to animal hospitals were examined for the presence of S. scabiei using a parasitological approach. The average prevalence of S. scabiei infection in pet dogs is 1.18% (95% confidence interval (CI): 0.85–1.52%). The p...

  18. Confidence Intervals for a Semiparametric Approach to Modeling Nonlinear Relations among Latent Variables

    Science.gov (United States)

    Pek, Jolynn; Losardo, Diane; Bauer, Daniel J.

    2011-01-01

    Compared to parametric models, nonparametric and semiparametric approaches to modeling nonlinearity between latent variables have the advantage of recovering global relationships of unknown functional form. Bauer (2005) proposed an indirect application of finite mixtures of structural equation models where latent components are estimated in the…

  19. Technical Report on Modeling for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-11

    The overall aim of this project is to develop a software package, called MetaQuant, that can determine the constituents of a complex microbial sample and estimate their relative abundances by analysis of metagenomic sequencing data. The goal for Task 1 is to create a generative model describing the stochastic process underlying the creation of sequence read pairs in the data set. The stages in this generative process include the selection of a source genome sequence for each read pair, with probability dependent on its abundance in the sample. The other stages describe the evolution of the source genome from its nearest common ancestor with a reference genome, breakage of the source DNA into short fragments, and the errors in sequencing the ends of the fragments to produce read pairs.

  20. Computing confidence intervals on solution costs for stochastic grid generation expansion problems.

    Energy Technology Data Exchange (ETDEWEB)

    Woodruff, David L..; Watson, Jean-Paul

    2010-12-01

    A range of core operations and planning problems for the national electrical grid are naturally formulated and solved as stochastic programming problems, which minimize expected costs subject to a range of uncertain outcomes relating to, for example, uncertain demands or generator output. A critical decision issue relating to such stochastic programs is: How many scenarios are required to ensure a specific error bound on the solution cost? Scenarios are the key mechanism used to sample from the uncertainty space, and the number of scenarios drives computational difficultly. We explore this question in the context of a long-term grid generation expansion problem, using a bounding procedure introduced by Mak, Morton, and Wood. We discuss experimental results using problem formulations independently minimizing expected cost and down-side risk. Our results indicate that we can use a surprisingly small number of scenarios to yield tight error bounds in the case of expected cost minimization, which has key practical implications. In contrast, error bounds in the case of risk minimization are significantly larger, suggesting more research is required in this area in order to achieve rigorous solutions for decision makers.

  1. Considering Teaching History and Calculating Confidence Intervals in Student Evaluations of Teaching Quality

    Science.gov (United States)

    Fraile, Rubén; Bosch-Morell, Francisco

    2015-01-01

    Lecturer promotion and tenure decisions are critical both for university management and for the affected lecturers. Therefore, they should be made cautiously and based on reliable information. Student evaluations of teaching quality are among the most used and analysed sources of such information. However, to date little attention has been paid in…

  2. Technical Report: Benchmarking for Quasispecies Abundance Inference with Confidence Intervals from Metagenomic Sequence Data

    Energy Technology Data Exchange (ETDEWEB)

    McLoughlin, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-22

    The software application “MetaQuant” was developed by our group at Lawrence Livermore National Laboratory (LLNL). It is designed to profile microbial populations in a sample using data from whole-genome shotgun (WGS) metagenomic DNA sequencing. Several other metagenomic profiling applications have been described in the literature. We ran a series of benchmark tests to compare the performance of MetaQuant against that of a few existing profiling tools, using real and simulated sequence datasets. This report describes our benchmarking procedure and results.

  3. Statistical Significance, Effect Size Reporting, and Confidence Intervals: Best Reporting Strategies

    Science.gov (United States)

    Capraro, Robert M.

    2004-01-01

    With great interest the author read the May 2002 editorial in the "Journal for Research in Mathematics Education (JRME)" (King, 2002) regarding changes to the 5th edition of the "Publication Manual of the American Psychological Association" (APA, 2001). Of special note to him, and of great import to the field of mathematics education research, are…

  4. Standard errors and confidence intervals of norm statistics for educational and psychological tests

    NARCIS (Netherlands)

    Oosterhuis, H.E.M.; van der Ark, L.A.; Sijtsma, K.

    2017-01-01

    Norm statistics allow for the interpretation of scores on psychological and educational tests, by relating the test score of an individual test taker to the test scores of individuals belonging to the same gender, age, or education groups, et cetera. Given the uncertainty due to sampling error, one

  5. Standard errors and confidence intervals of norm statistics for educational and psychological tests

    NARCIS (Netherlands)

    Oosterhuis, H.E.M.; van der Ark, L.A.; Sijtsma, K.

    Norm statistics allow for the interpretation of scores on psychological and educational tests, by relating the test score of an individual test taker to the test scores of individuals belonging to the same gender, age, or education groups, et cetera. Given the uncertainty due to sampling error, one

  6. Computing confidence intervals on solution costs for stochastic grid generation expansion problems

    International Nuclear Information System (INIS)

    Woodruff, David L.; Watson, Jean-Paul

    2010-01-01

    A range of core operations and planning problems for the national electrical grid are naturally formulated and solved as stochastic programming problems, which minimize expected costs subject to a range of uncertain outcomes relating to, for example, uncertain demands or generator output. A critical decision issue relating to such stochastic programs is: How many scenarios are required to ensure a specific error bound on the solution cost? Scenarios are the key mechanism used to sample from the uncertainty space, and the number of scenarios drives computational difficultly. We explore this question in the context of a long-term grid generation expansion problem, using a bounding procedure introduced by Mak, Morton, and Wood. We discuss experimental results using problem formulations independently minimizing expected cost and down-side risk. Our results indicate that we can use a surprisingly small number of scenarios to yield tight error bounds in the case of expected cost minimization, which has key practical implications. In contrast, error bounds in the case of risk minimization are significantly larger, suggesting more research is required in this area in order to achieve rigorous solutions for decision makers.

  7. Confidence intervals and hypothesis testing for the Permutation Entropy with an application to epilepsy

    Science.gov (United States)

    Traversaro, Francisco; O. Redelico, Francisco

    2018-04-01

    In nonlinear dynamics, and to a lesser extent in other fields, a widely used measure of complexity is the Permutation Entropy. But there is still no known method to determine the accuracy of this measure. There has been little research on the statistical properties of this quantity that characterize time series. The literature describes some resampling methods of quantities used in nonlinear dynamics - as the largest Lyapunov exponent - but these seems to fail. In this contribution, we propose a parametric bootstrap methodology using a symbolic representation of the time series to obtain the distribution of the Permutation Entropy estimator. We perform several time series simulations given by well-known stochastic processes: the 1/fα noise family, and show in each case that the proposed accuracy measure is as efficient as the one obtained by the frequentist approach of repeating the experiment. The complexity of brain electrical activity, measured by the Permutation Entropy, has been extensively used in epilepsy research for detection in dynamical changes in electroencephalogram (EEG) signal with no consideration of the variability of this complexity measure. An application of the parametric bootstrap methodology is used to compare normal and pre-ictal EEG signals.

  8. Measuring the Dependence between Two Point Processes through Confidence Intervals for the Second Order Distribution.

    Science.gov (United States)

    1987-09-01

    in neurophysiology, which are very briefly described as follows (for further details see e.g. Bryant, Ruiz Marcos , and Segundo, 1973). Two neurons, A...Poisson process, and NB being an equilibrium rcnewal process on (-oo, oo) (for a definition and a construction see pp. 517-519 of Karlin and Taylor, 1975...order intensities of a bivariate stationary point process. J. Roy. Statist. Soc. Ser. B 38, 60-66. Bryant, H. L., Ruiz Marcos , A., and Segundo, J. P

  9. Prevalence of orofacial clefts and risks for nonsyndromic cleft lip with or without cleft palate in newborns at a university hospital from West Mexico.

    Science.gov (United States)

    Corona-Rivera, Jorge Román; Bobadilla-Morales, Lucina; Corona-Rivera, Alfredo; Peña-Padilla, Christian; Olvera-Molina, Sandra; Orozco-Martín, Miriam A; García-Cruz, Diana; Ríos-Flores, Izabel M; Gómez-Rodríguez, Brian Gabriel; Rivas-Soto, Gemma; Pérez-Molina, J Jesús

    2018-02-19

    We determined the overall prevalence of typical orofacial clefts and the potential risks for nonsyndromic cleft lip with or without cleft palate in a university hospital from West México. For the prevalence, 227 liveborn infants with typical orofacial clefts were included from a total of 81,193 births occurred during the period 2009-2016 at the "Dr. Juan I. Menchaca" Civil Hospital of Guadalajara (Guadalajara, Jalisco, Mexico). To evaluate potential risks, a case-control study was conducted among 420 newborns, including only those 105 patients with nonsyndromic cleft lip with or without cleft palate (cases), and 315 infants without birth defects (controls). Data were analyzed using multivariable logistic regression analysis expressed as adjusted odds ratio with 95% confidence intervals . The overall prevalence for typical orofacial clefts was 28 per 10,000 (95% confidence interval: 24.3-31.6), or 1 per 358 live births. The mean values for the prepregnancy weight, antepartum weight, and pre-pregnancy body mass index were statistically higher among the mothers of cases. Infants with nonsyndromic cleft lip with or without cleft palate had a significantly higher risk for previous history of any type of congenital anomaly (adjusted odds ratio: 2.7; 95% confidence interval: 1.4-5.1), history of a relative with cleft lip with or without cleft palate (adjusted odds ratio: 19.6; 95% confidence interval: 8.2-47.1), and first-trimester exposures to progestogens (adjusted odds ratio: 6.8; 95% CI 1.8-25.3), hyperthermia (adjusted odds ratio: 3.4; 95% confidence interval: 1.1-10.6), and common cold (adjusted odds ratio: 3.6; 95% confidence interval: 1.1-11.9). These risks could have contributed to explain the high prevalence of orofacial clefts in our region of Mexico, emphasizing that except for history of relatives with cleft lip with or without cleft palate, most are susceptible of modification. © 2018 Japanese Teratology Society.

  10. Prevalence of tics in schoolchildren in central Spain: a population-based study.

    Science.gov (United States)

    Cubo, Esther; Gabriel y Galán, José María Trejo; Villaverde, Vanesa Ausín; Velasco, Sara Sáez; Benito, Vanesa Delgado; Macarrón, Jesús Vicente; Guevara, José Cordero; Louis, Elan D; Benito-León, Julián

    2011-08-01

    Tic disorders constitute a neurodevelopmental disorder of childhood. This study sought to determine the prevalence of tic disorders in a school-based sample. A randomized sample of 1158 schoolchildren, based on clusters (classrooms) in the province of Burgos (Spain), was identified on a stratified sampling frame combining types of educational center and setting (mainstream schools and special education), using a two-phase approach (screening and diagnosis ascertainment by a neurologist). Tics with/without impairment criterion were diagnosed according to Diagnostic and Statistical Manual of Mental Disorders criteria. In mainstream schools, tics were observed in 125/741 students (16.86%; 95% confidence interval, 14.10-19.63), and were more frequent in boys (87/448, 19.42%; 95% confidence interval, 15.64-23.19) compared with girls (38/293, 12.96%; 95% confidence interval, 8.95-16.98; P = 0.03). In special education centers, tics disorders were observed in 11/54 of children (20.37%; 95% confidence interval, 8.70-32.03). Overall, tics with impairment criteria were less frequent than tics without impairment criteria (4.65% vs 11.85%, P tics (6.07%) and Tourette syndrome (5.26%). Tic disorders are common in childhood, and the use or nonuse of impairment criteria exerts a significant impact on tic prevalence estimates. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. High Confidence Software and Systems Research Needs

    Data.gov (United States)

    Networking and Information Technology Research and Development, Executive Office of the President — This White Paper presents a survey of high confidence software and systems research needs. It has been prepared by the High Confidence Software and Systems...

  12. A mathematical framework for statistical decision confidence

    Science.gov (United States)

    Hangya, Balázs; Sanders, Joshua I.; Kepecs, Adam

    2017-01-01

    Decision confidence is a forecast about the probability that a decision will be correct. From a statistical perspective decision confidence can be defined as the Bayesian posterior probability that the chosen option is correct based on the evidence contributing to it. Here we used this formal definition as a starting point to develop a normative statistical framework for decision confidence. Our goal was to make general predictions that do not depend on the structure of the noise or a specific algorithm for estimating confidence. We analytically proved several interrelations between statistical decision confidence and observable decision measures, such as evidence discriminability, choice and accuracy. These interrelationships specify necessary signatures of decision confidence in terms of externally quantifiable variables that can be empirically tested. Our results lay the foundations for a mathematically rigorous treatment of decision confidence that can lead to a common framework for understanding confidence across different research domains, from human and animal behavior to neural representations. PMID:27391683

  13. Action-specific disruption of perceptual confidence.

    Science.gov (United States)

    Fleming, Stephen M; Maniscalco, Brian; Ko, Yoshiaki; Amendi, Namema; Ro, Tony; Lau, Hakwan

    2015-01-01

    Theoretical models of perception assume that confidence is related to the quality or strength of sensory processing. Counter to this intuitive view, we showed in the present research that the motor system also contributes to judgments of perceptual confidence. In two experiments, we used transcranial magnetic stimulation (TMS) to manipulate response-specific representations in the premotor cortex, selectively disrupting postresponse confidence in visual discrimination judgments. Specifically, stimulation of the motor representation associated with the unchosen response reduced confidence in correct responses, thereby reducing metacognitive capacity without changing visual discrimination performance. Effects of TMS on confidence were observed when stimulation was applied both before and after the response occurred, which suggests that confidence depends on late-stage metacognitive processes. These results place constraints on models of perceptual confidence and metacognition by revealing that action-specific information in the premotor cortex contributes to perceptual confidence. © The Author(s) 2014.

  14. Inter-Pregnancy Interval

    African Journals Online (AJOL)

    Buchi

    This definition excludes. 1, 2 miscarriage as a preceding pregnancy event. Often the IPI is calculated as ... Inter-pregnancy interval of <6 months was significantly associated with an increased risk of adverse subsequent pregnancy outcomes. Mothers 35 years or older at start of childbearing have the highest risk compared to.

  15. Interval methods: An introduction

    DEFF Research Database (Denmark)

    Achenie, L.E.K.; Kreinovich, V.; Madsen, Kaj

    2006-01-01

    This chapter contains selected papers presented at the Minisymposium on Interval Methods of the PARA'04 Workshop '' State-of-the-Art in Scientific Computing ''. The emphasis of the workshop was on high-performance computing (HPC). The ongoing development of ever more advanced computers provides...

  16. Confidence Building Strategies in the Public Schools.

    Science.gov (United States)

    Achilles, C. M.; And Others

    1985-01-01

    Data from the Phi Delta Kappa Commission on Public Confidence in Education indicate that "high-confidence" schools make greater use of marketing and public relations strategies. Teacher attitudes were ranked first and administrator attitudes second by 409 respondents for both gain and loss of confidence in schools. (MLF)

  17. 75 FR 81037 - Waste Confidence Decision Update

    Science.gov (United States)

    2010-12-23

    ... NUCLEAR REGULATORY COMMISSION 10 CFR Part 51 [NRC-2008-0482] Waste Confidence Decision Update AGENCY: Nuclear Regulatory Commission. ACTION: Update and final revision of Waste Confidence Decision. SUMMARY: The U.S. Nuclear Regulatory Commission (NRC or Commission) is updating its Waste Confidence...

  18. Self Confidence Spillovers and Motivated Beliefs

    DEFF Research Database (Denmark)

    Banerjee, Ritwik; Gupta, Nabanita Datta; Villeval, Marie Claire

    that success when competing in a task increases the performers’ self-confidence and competitiveness in the subsequent task. We also find that such spillovers affect the self-confidence of low-status individuals more than that of high-status individuals. Receiving good news under Affirmative Action, however......, boosts confidence across tasks regardless of the caste status....

  19. Systemic lupus erythematosus: the first italian prevalence study

    Directory of Open Access Journals (Sweden)

    M. Manfredi

    2011-09-01

    Full Text Available Objectives: The aim of the study was the assessment of SLE prevalence in an adult population. The study was perfomed on a sample of more than 30.000 patients over 18 resident in the Florence sub-area of Scandicci- Le Signe (Italy on the basis of the register of general practitioners (GPs. Methods: Twenty GPs gave the Lupus Screening Questionnaire (LQS to their patients. The LQS has been completed by 32.521 patients resident in Scandicci, Lastra a Signa and Signa area. On the basis of the LQS analysis an SLE diagnosis was suspected in 30 patients. These 30 patients have been investigated by routine exams, antinuclear antibodies and have been refered to rheumatologist to assess the SLE diagnosis and disease activity (ECLAM Score. Results: The overall population aged >18 years was 71.204 ( 42.474 living in Scandicci, 15.368 in Lastra a Signa and 13.362 in Signa. The diagnosis was confirmed in 23 out of the 30 suspected SLE patients. Eleven out of the 23 SLE patients were from Scandicci, 6 from Lastra a Signa and the other 6 from Signa. The overall rate of SLE prevalence is 71/100.000 (1 case/1408 with a confidence interval of 95%, (confidence limits: 49-92. The rate of SLE prevalence in Scandicci is 81/100.000 (confidence limits: 42-121, in Lastra a Signa 62/100.000 (confidence limits: 32-92 and in Signa 65/100.000 (confidence limits: 36-94. Conclusion: This is the first epidemiological study on SLE prevalence in Italy. The rate of SLE prevalence is similar to that of other European studies. LQS is confirmed as an easy and reliable tool to assess SLE diagnosis also in the Italian population too.

  20. Prevalence and risk of migraine in patients with rosacea

    DEFF Research Database (Denmark)

    Egeberg, Alexander; Ashina, Messoud; Gaist, David

    2017-01-01

    BACKGROUND: Rosacea features increased neurovascular reactivity; migraine is a complex neurologic disorder characterized by recurrent episodes of headache associated with nausea and increased sensitivity to light and sound. OBJECTIVE: We evaluated the prevalence and risk of new-onset migraine...... in patients with rosacea. METHODS: All Danish individuals 18 years of age or older were linked in nationwide registers. Adjusted hazard ratios (HRs) were estimated by Cox regression. RESULTS: In the total cohort (n = 4,361,688), there were 49,475 patients with rosacea. Baseline prevalence of migraine was 7.......3% and 12.1% in the reference population and in patients with rosacea, respectively. The fully adjusted HR of migraine was 1.31 (95% confidence interval 1.23-1.39) for patients with rosacea. Patients with phymatous rosacea (n = 594) had no increased risk of migraine (adjusted HR 0.45; 95% confidence...

  1. Prevalence of human immunodeficiency virus infection and associated risk factors among prison inmates in the City of Florianópolis

    OpenAIRE

    Felisberto,Mariano; Saretto,Antonio Adalberto; Wopereis,Sandro; Treitinger,Arício; Machado,Marcos José; Spada,Celso

    2016-01-01

    Abstract INTRODUCTION This study aimed to estimate the prevalence of human immunodeficiency virus (HIV) infection among prison inmates and to define the behavioral profile of infected individuals. METHODS: In total, 147 individuals were interviewed and provided biological material. The study population consisted of male individuals who presented at the health unit of the Florianopolis State Penitentiary. RESULTS: The prevalence of HIV infection was 2.1% (95% confidence interval, 0.4-5.8...

  2. Applications of interval computations

    CERN Document Server

    Kreinovich, Vladik

    1996-01-01

    Primary Audience for the Book • Specialists in numerical computations who are interested in algorithms with automatic result verification. • Engineers, scientists, and practitioners who desire results with automatic verification and who would therefore benefit from the experience of suc­ cessful applications. • Students in applied mathematics and computer science who want to learn these methods. Goal Of the Book This book contains surveys of applications of interval computations, i. e. , appli­ cations of numerical methods with automatic result verification, that were pre­ sented at an international workshop on the subject in EI Paso, Texas, February 23-25, 1995. The purpose of this book is to disseminate detailed and surveyed information about existing and potential applications of this new growing field. Brief Description of the Papers At the most fundamental level, interval arithmetic operations work with sets: The result of a single arithmetic operation is the set of all possible results as the o...

  3. Establishing reference intervals in the coagulation laboratory.

    Science.gov (United States)

    Castellone, D D

    2017-05-01

    Obtaining a reference interval (RI) is a challenge for any laboratory and becomes more complicated in the coagulation laboratory due to testing on samples with limited stability on reagents that are poorly standardized. Reference intervals are required to be able to evaluate results in relation to a patients' hemostatic disorder. This becomes one of the most important tasks conducted in the coagulation laboratory. However, many laboratories lack the time, finances and in many cases the expertise to conduct this study. Many RI are obtained from package inserts, or from publications written by experts in lieu of laboratories conducting their own studies. An overview of validating reference intervals and options for verifying or transference of reference intervals is discussed. Based on the confidence interval and the acceptability of risk laboratories are willing to accept, coagulation laboratories have options to conduct robust studies for their RI. Data mining or global reference studies may help to provide data for age specific ranges. Pre-analytical variables and selection of healthy subjects have the largest impact on coagulation testing outcomes and need to be well controlled during the establishment of reference intervals. Laboratories have options in lieu of conducting a full validation on how to verify RI based on smaller RI studies or transference of RI after determining compatibility of the original RI study. © 2017 John Wiley & Sons Ltd.

  4. Prevalence of hyperhidrosis among medical students.

    Science.gov (United States)

    Westphal, Fernando Luiz; de Carvalho, Maria Auxiliadora Neves; Lima, Luiz Carlos; de Carvalho, Bruna Cecília Neves; Padilla, Rodrigo; Araújo, Katiúscia Karla Lêdo

    2011-01-01

    To identify the prevalence of hyperhidrosis among medical students of Manaus, State of Amazonas, Brazil. We conducted an observational, transversal, survey which examined the prevalence of primary hyperhidrosis among medical students of the Federal University of Amazonas and its relation to body mass index (BMI) and stress. Students were weighed and interviewed. We used questionnaires with questions recommended by the International Hyperhidrosis Society to relate hyperhidrosis to the daily activities of each person. Results were given by calculating the prevalence ratios and confidence intervals. Among the 293 students examined, it was found that a total of 16 (5.5%) students had barely tolerable or intolerable excessive sweating, interfering with daily activities. None had known causes of hyperhidrosis and 50% had family history. In all suffering from the condition the disease was bilateral, the mainly affected locations being: hands (35.7%), legs (21.4%), axilla (17.9), face (10 7%), back (7.1%), chest (3.6%) and abdomen (3.6%). There was no predominance regarding gender, age or BMI. We found a positive relationship with BMI and observed a prevalence ratio of 2.48 higher in overweight students than in normal weight or underweight ones. The prevalence of primary hyperhidrosis among medical students of Manaus was 5.5%. There is a positive non-statistical relationship with overweight and obesity. It was further noted an observational relationship with stress.

  5. The prevalence and determinants of hypothyroidism in hospitalized patients with type 2 diabetes mellitus.

    Science.gov (United States)

    Song, Fei; Bao, Cuiping; Deng, Meiyu; Xu, Hui; Fan, Meijuan; Paillard-Borg, Stéphanie; Xu, Weili; Qi, Xiuying

    2017-01-01

    The purpose of this study was to investigate the prevalence of hypothyroidism among hospitalized patients with type 2 diabetes mellitus and its related factors, and to assess the prevalence of macrovascular and microvascular diseases among type 2 diabetes mellitus inpatients with hypothyroidism and euthyroidism. A total of 1662 type 2 diabetes mellitus inpatients hospitalized at the Metabolic Diseases Hospital, Tianjin Medical University from 1 January 2008 to 1 March 2013 were included in this study. Information on demographic and anthropometric factors and additional variables related to hypothyroidism were collected from medical records. Prevalence rates were calculated and standardized using direct method based on the age-specific and sex-specific structure of all participants. Data were analyzed using binary logistic regression with adjustment for potential confounders. The prevalence of hypothyroidism among type 2 diabetes mellitus inpatients was 6.8 %, and 77.0 % of the patients with hypothyroidism had subclinical hypothyroidism. The prevalence of hypothyroidism increased with age, and was higher in women (10.8 %) than in men (3.4 %). Older age (odds ratio, 1.74; 95 % confidence interval, 1. 05 to 2.89), female gender (odds ratio, 2.02; 95 % confidence interval, 1.05 to 3.87), and positive thyroid peroxidase antibody (odds ratio, 4.99; 95 % confidence interval, 2.83 to 8.79) were associated with higher odds of hypothyroidism among type 2 diabetes mellitus inpatients. The type 2 diabetes mellitus inpatients with hypothyroidism had higher prevalence of cerebrovascular diseases than those with euthyroidism after adjustment for age and gender. The prevalence of hypothyroidism among type 2 diabetes mellitus inpatients was 6.8 %, and most patients had subclinical hypothyroidism. Older age, female gender, and positive thyroid peroxidase antibody could be indicators for detecting hypothyroidism in type 2 diabetes mellitus inpatients.

  6. Regional Competition for Confidence: Features of Formation

    Directory of Open Access Journals (Sweden)

    Irina Svyatoslavovna Vazhenina

    2016-09-01

    Full Text Available The increase in economic independence of the regions inevitably leads to an increase in the quality requirements of the regional economic policy. The key to successful regional policy, both during its development and implementation, is the understanding of the necessity of gaining confidence (at all levels, and the inevitable participation in the competition for confidence. The importance of confidence in the region is determined by its value as a competitive advantage in the struggle for partners, resources and tourists, and attracting investments. In today’s environment the focus of governments, regions and companies on long-term cooperation is clearly expressed, which is impossible without a high level of confidence between partners. Therefore, the most important competitive advantages of territories are intangible assets such as an attractive image and a good reputation, which builds up confidence of the population and partners. The higher the confidence in the region is, the broader is the range of potential partners, the larger is the planning horizon of long-term concerted action, the better are the chances of acquiring investment, the higher is the level of competitive immunity of the territories. The article defines competition for confidence as purposeful behavior of a market participant in economic environment, aimed at acquiring specific intangible competitive advantage – the confidence of the largest possible number of other market actors. The article also highlights the specifics of confidence as a competitive goal, presents factors contributing to the destruction of confidence, proposes a strategy to fight for confidence as a program of four steps, considers the factors which integrate regional confidence and offers several recommendations for the establishment of effective regional competition for confidence

  7. Exact one-sided confidence limits for Cohen's kappa as a measurement of agreement.

    Science.gov (United States)

    Shan, Guogen; Wang, Weizhen

    2017-04-01

    Cohen's kappa coefficient, κ, is a statistical measure of inter-rater agreement or inter-annotator agreement for qualitative items. In this paper, we focus on interval estimation of κ in the case of two raters and binary items. So far, only asymptotic and bootstrap intervals are available for κ due to its complexity. However, there is no guarantee that such intervals will capture κ with the desired nominal level 1- α. In other words, the statistical inferences based on these intervals are not reliable. We apply the Buehler method to obtain exact confidence intervals based on four widely used asymptotic intervals, three Wald-type confidence intervals and one interval constructed from a profile variance. These exact intervals are compared with regard to coverage probability and length for small to medium sample sizes. The exact intervals based on the Garner interval and the Lee and Tu interval are generally recommended for use in practice due to good performance in both coverage probability and length.

  8. Interval orders and reverse mathematics

    OpenAIRE

    Marcone, Alberto

    2006-01-01

    We study the reverse mathematics of interval orders. We establish the logical strength of the implications between various definitions of the notion of interval order. We also consider the strength of different versions of the characterization theorem for interval orders: a partial order is an interval order if and only if it does not contain $2 \\oplus 2$. We also study proper interval orders and their characterization theorem: a partial order is a proper interval order if and only if it cont...

  9. Quality of Vitamin K Antagonist Anticoagulation in Spain: Prevalence of Poor Control and Associated Factors.

    Science.gov (United States)

    Anguita Sánchez, Manuel; Bertomeu Martínez, Vicente; Cequier Fillat, Ángel

    2015-09-01

    To study the prevalence of poorly controlled vitamin K antagonist anticoagulation in Spain in patients with nonvalvular atrial fibrillation, and to identify associated factors. We studied 1056 consecutive patients seen at 120 cardiology clinics in Spain between November 2013 and March 2014. We analyzed the international normalized ratio from the 6 months prior to the patient's visit, calculating the prevalence of poorly controlled anticoagulation, defined as < 65% time in therapeutic range using the Rosendaal method. Mean age was 73.6 years (standard deviation, 9.8 years); women accounted for 42% of patients. The prevalence of poorly controlled anticoagulation was 47.3%. Mean time in therapeutic range was 63.8% (25.9%). The following factors were independently associated with poorly controlled anticoagulation: kidney disease (odds ratio = 1.53; 95% confidence interval, 1.08-2.18; P = .018), routine nonsteroidal anti-inflammatory drugs (odds ratio = 1.79; 95% confidence interval, 1.20-2.79; P = .004), antiplatelet therapy (odds ratio = 2.16; 95% confidence interval, 1.49-3.12; P < .0001) and absence of angiotensin receptor blockers (odds ratio = 1.39; 95% confidence interval, 1.08-1.79; P = .011). There is a high prevalence of poorly controlled vitamin K antagonist anticoagulation in Spain. Factors associated with poor control are kidney disease, routine nonsteroidal anti-inflammatory drugs, antiplatelet use, and absence of angiotensin receptor blockers. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  10. High preoperative prevalence of deep venous thrombosis in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Stender, M T; Nielsen, T S H; Frøkjaer, J B

    2007-01-01

    , with a prevalence of 16 per cent in women (12 of 76) versus 2.6 per cent in men (three of 117 (adjusted odds ratio (OR) 5.8 (95 per cent confidence interval (c.i.) 1.4 to 23.2)). The risk of DVT was strongly correlated with increasing American Society of Anesthesiologists (ASA) risk score: adjusted OR 6.8 (95 per...

  11. Feature Selection Based on Confidence Machine

    OpenAIRE

    Liu, Chang; Xu, Yi

    2014-01-01

    In machine learning and pattern recognition, feature selection has been a hot topic in the literature. Unsupervised feature selection is challenging due to the loss of labels which would supply the related information.How to define an appropriate metric is the key for feature selection. We propose a filter method for unsupervised feature selection which is based on the Confidence Machine. Confidence Machine offers an estimation of confidence on a feature'reliability. In this paper, we provide...

  12. The integrated model of sport confidence: a canonical correlation and mediational analysis.

    Science.gov (United States)

    Koehn, Stefan; Pearce, Alan J; Morris, Tony

    2013-12-01

    The main purpose of the study was to examine crucial parts of Vealey's (2001) integrated framework hypothesizing that sport confidence is a mediating variable between sources of sport confidence (including achievement, self-regulation, and social climate) and athletes' affect in competition. The sample consisted of 386 athletes, who completed the Sources of Sport Confidence Questionnaire, Trait Sport Confidence Inventory, and Dispositional Flow Scale-2. Canonical correlation analysis revealed a confidence-achievement dimension underlying flow. Bias-corrected bootstrap confidence intervals in AMOS 20.0 were used in examining mediation effects between source domains and dispositional flow. Results showed that sport confidence partially mediated the relationship between achievement and self-regulation domains and flow, whereas no significant mediation was found for social climate. On a subscale level, full mediation models emerged for achievement and flow dimensions of challenge-skills balance, clear goals, and concentration on the task at hand.

  13. A model for developing disability confidence.

    Science.gov (United States)

    Lindsay, Sally; Cancelliere, Sara

    2017-05-15

    Many clinicians, educators, and employers lack disability confidence which can affect their interactions with, and inclusion of people with disabilities. Our objective was to explore how disability confidence developed among youth who volunteered with children who have a disability. We conducted 30 in-depth interviews (16 without a disability, 14 with disabilities), with youth aged 15-25. We analyzed our data using an interpretive, qualitative, thematic approach. We identified four main themes that led to the progression of disability confidence including: (1) "disability discomfort," referring to lacking knowledge about disability and experiencing unease around people with disabilities; (2) "reaching beyond comfort zone" where participants increased their understanding of disability and became sensitized to difference; (3) "broadened perspectives" where youth gained exposure to people with disabilities and challenged common misperceptions and stereotypes; and (4) "disability confidence" which includes having knowledge of people with disabilities, inclusive, and positive attitudes towards them. Volunteering is one way that can help to develop disability confidence. Youth with and without disabilities both reported a similar process of developing disability confidence; however, there were nuances between the two groups. Implications for Rehabilitation The development of disability confidence is important for enhancing the social inclusion of people with disabilities. Volunteering with people who have a disability, or a disability different from their own, can help to develop disability confidence which involves positive attitudes, empathy, and appropriate communication skills. Clinicians, educators, and employers should consider promoting working with disabled people through such avenues as volunteering or service learning to gain disability confidence.

  14. Chaos on the interval

    CERN Document Server

    Ruette, Sylvie

    2017-01-01

    The aim of this book is to survey the relations between the various kinds of chaos and related notions for continuous interval maps from a topological point of view. The papers on this topic are numerous and widely scattered in the literature; some of them are little known, difficult to find, or originally published in Russian, Ukrainian, or Chinese. Dynamical systems given by the iteration of a continuous map on an interval have been broadly studied because they are simple but nevertheless exhibit complex behaviors. They also allow numerical simulations, which enabled the discovery of some chaotic phenomena. Moreover, the "most interesting" part of some higher-dimensional systems can be of lower dimension, which allows, in some cases, boiling it down to systems in dimension one. Some of the more recent developments such as distributional chaos, the relation between entropy and Li-Yorke chaos, sequence entropy, and maps with infinitely many branches are presented in book form for the first time. The author gi...

  15. CKD Prevalence Varies across the European General Population

    Science.gov (United States)

    Stel, Vianda S.; Gambaro, Giovanni; Hallan, Stein; Völzke, Henry; Ärnlöv, Johan; Kastarinen, Mika; Guessous, Idris; Vinhas, José; Stengel, Bénédicte; Brenner, Hermann; Chudek, Jerzy; Romundstad, Solfrid; Tomson, Charles; Gonzalez, Alfonso Otero; Bello, Aminu K.; Ferrieres, Jean; Palmieri, Luigi; Browne, Gemma; Capuano, Vincenzo; Van Biesen, Wim; Zoccali, Carmine; Gansevoort, Ron; Navis, Gerjan; Rothenbacher, Dietrich; Ferraro, Pietro Manuel; Nitsch, Dorothea; Wanner, Christoph; Jager, Kitty J.

    2016-01-01

    CKD prevalence estimation is central to CKD management and prevention planning at the population level. This study estimated CKD prevalence in the European adult general population and investigated international variation in CKD prevalence by age, sex, and presence of diabetes, hypertension, and obesity. We collected data from 19 general-population studies from 13 European countries. CKD stages 1–5 was defined as eGFR30 mg/g, and CKD stages 3–5 was defined as eGFR<60 ml/min per 1.73 m2. CKD prevalence was age- and sex-standardized to the population of the 27 Member States of the European Union (EU27). We found considerable differences in both CKD stages 1–5 and CKD stages 3–5 prevalence across European study populations. The adjusted CKD stages 1–5 prevalence varied between 3.31% (95% confidence interval [95% CI], 3.30% to 3.33%) in Norway and 17.3% (95% CI, 16.5% to 18.1%) in northeast Germany. The adjusted CKD stages 3–5 prevalence varied between 1.0% (95% CI, 0.7% to 1.3%) in central Italy and 5.9% (95% CI, 5.2% to 6.6%) in northeast Germany. The variation in CKD prevalence stratified by diabetes, hypertension, and obesity status followed the same pattern as the overall prevalence. In conclusion, this large-scale attempt to carefully characterize CKD prevalence in Europe identified substantial variation in CKD prevalence that appears to be due to factors other than the prevalence of diabetes, hypertension, and obesity. PMID:26701975

  16. Prevalence of vision impairment and refractive error in school children in Ba Ria - Vung Tau province, Vietnam.

    Science.gov (United States)

    Paudel, Prakash; Ramson, Prasidh; Naduvilath, Thomas; Wilson, David; Phuong, Ha Thanh; Ho, Suit M; Giap, Nguyen V

    2014-04-01

    To assess the prevalence of vision impairment and refractive error in school children 12-15 years of age in Ba Ria - Vung Tau province, Vietnam. Prospective, cross-sectional study. 2238 secondary school children. Subjects were selected based on stratified multistage cluster sampling of 13 secondary schools from urban, rural and semi-urban areas. The examination included visual acuity measurements, ocular motility evaluation, cycloplegic autorefraction, and examination of the external eye, anterior segment, media and fundus. Visual acuity and principal cause of vision impairment. The prevalence of uncorrected and presenting visual acuity ≤6/12 in the better eye were 19.4% (95% confidence interval, 12.5-26.3) and 12.2% (95% confidence interval, 8.8-15.6), respectively. Refractive error was the cause of vision impairment in 92.7%, amblyopia in 2.2%, cataract in 0.7%, retinal disorders in 0.4%, other causes in 1.5% and unexplained causes in the remaining 2.6%. The prevalence of vision impairment due to myopia in either eye (-0.50 diopter or greater) was 20.4% (95% confidence interval, 12.8-28.0), hyperopia (≥2.00 D) was 0.4% (95% confidence interval, 0.0-0.7) and emmetropia with astigmatism (≥0.75 D) was 0.7% (95% confidence interval, 0.2-1.2). Vision impairment due to myopia was associated with higher school grade and increased time spent reading and working on a computer. Uncorrected refractive error, particularly myopia, among secondary school children in Vietnam is a major public health problem. School-based eye health initiative such as refractive error screening is warranted to reduce vision impairment. © 2013 The Authors. Clinical & Experimental Ophthalmology published by Wiley Publishing Asia Pty Ltd on behalf of Royal Australian and New Zealand College of Ophthalmologists.

  17. Prevalence of vision impairment and refractive error in school children in Ba Ria – Vung Tau province, Vietnam

    Science.gov (United States)

    Paudel, Prakash; Ramson, Prasidh; Naduvilath, Thomas; Wilson, David; Phuong, Ha Thanh; Ho, Suit M; Giap, Nguyen V

    2014-01-01

    Background To assess the prevalence of vision impairment and refractive error in school children 12–15 years of age in Ba Ria – Vung Tau province, Vietnam. Design Prospective, cross-sectional study. Participants 2238 secondary school children. Methods Subjects were selected based on stratified multistage cluster sampling of 13 secondary schools from urban, rural and semi-urban areas. The examination included visual acuity measurements, ocular motility evaluation, cycloplegic autorefraction, and examination of the external eye, anterior segment, media and fundus. Main Outcome Measures Visual acuity and principal cause of vision impairment. Results The prevalence of uncorrected and presenting visual acuity ≤6/12 in the better eye were 19.4% (95% confidence interval, 12.5–26.3) and 12.2% (95% confidence interval, 8.8–15.6), respectively. Refractive error was the cause of vision impairment in 92.7%, amblyopia in 2.2%, cataract in 0.7%, retinal disorders in 0.4%, other causes in 1.5% and unexplained causes in the remaining 2.6%. The prevalence of vision impairment due to myopia in either eye (–0.50 diopter or greater) was 20.4% (95% confidence interval, 12.8–28.0), hyperopia (≥2.00 D) was 0.4% (95% confidence interval, 0.0–0.7) and emmetropia with astigmatism (≥0.75 D) was 0.7% (95% confidence interval, 0.2–1.2). Vision impairment due to myopia was associated with higher school grade and increased time spent reading and working on a computer. Conclusions Uncorrected refractive error, particularly myopia, among secondary school children in Vietnam is a major public health problem. School-based eye health initiative such as refractive error screening is warranted to reduce vision impairment. PMID:24299145

  18. Financial Literacy, Confidence and Financial Advice Seeking

    NARCIS (Netherlands)

    Kramer, Marc M.

    2016-01-01

    We find that people with higher confidence in their own financial literacy are less likely to seek financial advice, but no relation between objective measures of literacy and advice seeking. The negative association between confidence and advice seeking is more pronounced among wealthy households.

  19. Confidence rating of marine eutrophication assessments

    DEFF Research Database (Denmark)

    Murray, Ciarán; Andersen, Jesper Harbo; Kaartokallio, Hermanni

    2011-01-01

    This report presents the development of a methodology for assessing confidence in eutrophication status classifications. The method can be considered as a secondary assessment, supporting the primary assessment of eutrophication status. The confidence assessment is based on a transparent scoring ...... of the marine environment....

  20. Examining Response Confidence in Multiple Text Tasks

    Science.gov (United States)

    List, Alexandra; Alexander, Patricia A.

    2015-01-01

    Students' confidence in their responses to a multiple text-processing task and their justifications for those confidence ratings were investigated. Specifically, 215 undergraduates responded to two academic questions, differing by type (i.e., discrete and open-ended) and by domain (i.e., developmental psychology and astrophysics), using a digital…

  1. Confidence and Competence with Mathematical Procedures

    Science.gov (United States)

    Foster, Colin

    2016-01-01

    Confidence assessment (CA), in which students state alongside each of their answers a confidence level expressing how certain they are, has been employed successfully within higher education. However, it has not been widely explored with school pupils. This study examined how school mathematics pupils (N?=?345) in five different secondary schools…

  2. Hypercorrection of High Confidence Errors in Children

    Science.gov (United States)

    Metcalfe, Janet; Finn, Bridgid

    2012-01-01

    Three experiments investigated whether the hypercorrection effect--the finding that errors committed with high confidence are easier, rather than more difficult, to correct than are errors committed with low confidence--occurs in grade school children as it does in young adults. All three experiments showed that Grade 3-6 children hypercorrected…

  3. Building Scientific Confidence in the Development and ...

    Science.gov (United States)

    Building Scientific Confidence in the Development and Evaluation of Read-Across Using Tox21 Approaches Slide presentation at GlobalChem conference and workshop in Washington, DC on Case Study on Building Scientific Confidence in the Development and Evaluation of Read-Across Using Tox21 Approaches

  4. Consumer confidence or the business cycle

    DEFF Research Database (Denmark)

    Møller, Stig Vinther; Nørholm, Henrik; Rangvid, Jesper

    2014-01-01

    Answer: The business cycle. We show that consumer confidence and the output gap both excess returns on stocks in many European countries: When the output gap is positive (the economy is doing well), expected returns are low, and when consumer confidence is high, expected returns are also low...

  5. Aging and Confidence Judgments in Item Recognition

    Science.gov (United States)

    Voskuilen, Chelsea; Ratcliff, Roger; McKoon, Gail

    2018-01-01

    We examined the effects of aging on performance in an item-recognition experiment with confidence judgments. A model for confidence judgments and response time (RTs; Ratcliff & Starns, 2013) was used to fit a large amount of data from a new sample of older adults and a previously reported sample of younger adults. This model of confidence…

  6. Interval Female Sterilization.

    Science.gov (United States)

    Stuart, Gretchen S; Ramesh, Shanthi S

    2018-01-01

    Female sterilization is relied on by nearly one in three women aged 35-44 years in the United States. Sterilization procedures are among the most common procedures that obstetrician-gynecologists perform. The most frequent sterilization procedures include postpartum tubal ligation, laparoscopic tubal disruption or salpingectomy, and hysteroscopic tubal occlusion. The informed consent process for sterilization is crucial and requires shared decision-making between the patient and the health care provider. Counseling should include the specific risks and benefits of the specific surgical approaches. Additionally, women should be counseled on the alternatives to sterilization, including intrauterine contraceptives and subdermal contraceptive implants. Complications, including unplanned pregnancy after successful female sterilization, are rare. The objectives of this Clinical Expert Series are to describe the epidemiology of female sterilization, access to postpartum sterilization, advances in interval sterilization techniques, and clinical considerations in caring for women requesting sterilization.

  7. Multichannel interval timer

    International Nuclear Information System (INIS)

    Turko, B.T.

    1983-10-01

    A CAMAC based modular multichannel interval timer is described. The timer comprises twelve high resolution time digitizers with a common start enabling twelve independent stop inputs. Ten time ranges from 2.5 μs to 1.3 μs can be preset. Time can be read out in twelve 24-bit words either via CAMAC Crate Controller or an external FIFO register. LSB time calibration is 78.125 ps. An additional word reads out the operational status of twelve stop channels. The system consists of two modules. The analog module contains a reference clock and 13 analog time stretchers. The digital module contains counters, logic and interface circuits. The timer has an excellent differential linearity, thermal stability and crosstalk free performance

  8. Self-confidence and metacognitive processes

    Directory of Open Access Journals (Sweden)

    Kleitman Sabina

    2005-01-01

    Full Text Available This paper examines the status of Self-confidence trait. Two studies strongly suggest that Self-confidence is a component of metacognition. In the first study, participants (N=132 were administered measures of Self-concept, a newly devised Memory and Reasoning Competence Inventory (MARCI, and a Verbal Reasoning Test (VRT. The results indicate a significant relationship between confidence ratings on the VRT and the Reasoning component of MARCI. The second study (N=296 employed an extensive battery of cognitive tests and several metacognitive measures. Results indicate the presence of robust Self-confidence and Metacognitive Awareness factors, and a significant correlation between them. Self-confidence taps not only processes linked to performance on items that have correct answers, but also beliefs about events that may never occur.

  9. Prevalence of corporal punishment among students in Washington State schools.

    Science.gov (United States)

    Grossman, D C; Rauh, M J; Rivara, F P

    1995-05-01

    To determine the prevalence of corporal punishment in Washington State and the factors associated with its use in Washington elementary and secondary schools. Cross-sectional mail survey performed during the summer of 1992. All elementary and secondary schools in the state of Washington. One thousand eighteen schools (47%) responded to the survey, of which 80% were publicly funded and 63% were located in urban areas. The study sample closely resembled the profile of all schools in the state. Almost 11% of participating schools permitted corporal punishment at the time of the survey and 3.2% reported its actual use during the 1991-1992 school year, resulting in an estimated prevalence of 7.2 incidents per 1000 students per year. Sixteen percent of corporal punishment actions occurred in schools not permitting its use. Ninety percent of public schools relied on district policy regarding corporal punishment. School characteristics associated with the use of corporal punishment included rural location (crude odds ratio, 2.2; 95% confidence interval, 1.5 to 3.4), enrollment of less than 500 students (crude odds ratio, 1.7; 95% confidence interval, 1.1 to 2.7), and kindergarten to eighth-grade or kindergarten to 12th-grade enrollment (crude odds ratio, 2.5; 95% confidence interval, 1.6 to 3.9). The lack of a statewide ban on school corporal punishment at the time of this survey was associated with the continued use of corporal punishment against children in districts that continued to permit it. School policies against corporal punishment were associated with much lower prevalence. Continued efforts are needed to enact and enforce laws in the remaining states that have not yet banned corporal punishment.

  10. Prevalence, determinants and prognosis of pulmonary hypertension among hemodialysis patients

    Science.gov (United States)

    Agarwal, Rajiv

    2012-01-01

    Background The prevalence, determinants and prognosis of pulmonary hypertension among long-term hemodialysis patients in the USA are poorly understood. Methods A cross-sectional survey of prevalence and determinants of pulmonary hypertension was performed, followed by longitudinal follow-up for all-cause mortality. Pulmonary hypertension was defined as an estimated systolic pulmonary artery pressure of >35 mmHg using echocardiograms performed within an hour after the end of dialysis. Results Prevalent in 110/288 patients (38%), the independent determinants of pulmonary hypertension were the following: left atrial diameter (odds ratio 10.1 per cm/m2, P pulmonary hypertension (53%, CMR 168.9/1000 patient-years) and 39 among 178 without pulmonary hypertension (22%, CMR 52.5/1000 patient-years) [unadjusted hazard ratio (HR) for death 2.12 (95% confidence interval 1.41–3.19), P pulmonary hypertension remained an independent predictor for all-cause mortality [HR 2.17 (95% confidence interval 1.31–3.61), P pulmonary hypertension is common and is strongly associated with an enlarged left atrium and poor long-term survival. Reducing left atrial size such as through volume control may be an attractive target to improve pulmonary hypertension. Improving pulmonary hypertension in this group of patients may improve the dismal outcomes. PMID:22290987

  11. Dietary intake related to prevalent functional limitations in midlife women.

    Science.gov (United States)

    Tomey, Kristin M; Sowers, Maryfran R; Crandall, Carolyn; Johnston, Janet; Jannausch, Mary; Yosef, Matheos

    2008-04-15

    Physical functioning measures are considered integrated markers of the aging process. This prospective investigation examined relations between dietary intake of women at midlife in 1996-1997 and prevalence of physical functioning limitations 4 years later, defined by the Medical Outcomes Study Short-Form 36. The sample included 2,160 multiethnic women, aged 42-52 years, from six geographic areas participating in the Study of Women's Health Across the Nation (SWAN). Associations between measures of diet quality and number of fruit and vegetable servings and prevalent physical functional limitations (no, moderate, or substantial limitations) were tested by logistic regression. The prevalence of moderate and substantial functional limitations was 31% and 10%, respectively. Women in the highest quartile of cholesterol intake had 40% greater odds (odds ratio = 1.4, 95% confidence interval: 1.1, 1.8) of being more limited versus those in the lowest quartile. Women in the highest quartile of fat and saturated fat intakes were 50% and 60% more likely to be more limited, with respective odds ratios of 1.5 and 1.6 (95% confidence intervals: 1.2, 2.0 and 1.2, 2.1) versus those in the lowest quartiles. Lower fruit, vegetable, and fiber intakes were related to reporting greater functional limitations. Modifying dietary practices could be important in minimizing physical limitations.

  12. Back pain prevalence in adolescent athletes.

    Science.gov (United States)

    Müller, J; Müller, S; Stoll, J; Fröhlich, K; Otto, C; Mayer, F

    2017-04-01

    The research aimed to investigate back pain (BP) prevalence in a large cohort of young athletes with respect to age, gender, and sport discipline. BP (within the last 7 days) was assessed with a face scale (face 1-2 = no pain; face 3-5 = pain) in 2116 athletes (m/f 61%/39%; 13.3 ± 1.7 years; 163.0 ± 11.8 cm; 52.6 ± 13.9 kg; 4.9 ± 2.7 training years; 8.4 ± 5.7 training h/week). Four different sports categories were devised (a: combat sports, b: game sports; c: explosive strength sport; d: endurance sport). Analysis was described descriptively, regarding age, gender, and sport. In addition, 95% confidence intervals (CI) were calculated. About 168 (8%) athletes were allocated into the BP group. About 9% of females and 7% of males reported BP. Athletes, 11-13 years, showed a prevalence of 2-4%; while prevalence increased to 12-20% in 14- to 17-year olds. Considering sport discipline, prevalence ranged from 3% (soccer) to 14% (canoeing). Prevalences in weight lifting, judo, wrestling, rowing, and shooting were ≥10%; in boxing, soccer, handball, cycling, and horse riding, ≤6%. 95% CI ranged between 0.08-0.11. BP exists in adolescent athletes, but is uncommon and shows no gender differences. A prevalence increase after age 14 is obvious. Differentiated prevention programs in daily training routines might address sport discipline-specific BP prevalence. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. We will be champions: Leaders' confidence in 'us' inspires team members' team confidence and performance.

    Science.gov (United States)

    Fransen, K; Steffens, N K; Haslam, S A; Vanbeselaere, N; Vande Broek, G; Boen, F

    2016-12-01

    The present research examines the impact of leaders' confidence in their team on the team confidence and performance of their teammates. In an experiment involving newly assembled soccer teams, we manipulated the team confidence expressed by the team leader (high vs neutral vs low) and assessed team members' responses and performance as they unfolded during a competition (i.e., in a first baseline session and a second test session). Our findings pointed to team confidence contagion such that when the leader had expressed high (rather than neutral or low) team confidence, team members perceived their team to be more efficacious and were more confident in the team's ability to win. Moreover, leaders' team confidence affected individual and team performance such that teams led by a highly confident leader performed better than those led by a less confident leader. Finally, the results supported a hypothesized mediational model in showing that the effect of leaders' confidence on team members' team confidence and performance was mediated by the leader's perceived identity leadership and members' team identification. In conclusion, the findings of this experiment suggest that leaders' team confidence can enhance members' team confidence and performance by fostering members' identification with the team. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Interval by interval analysis of commercial drilling speed

    Energy Technology Data Exchange (ETDEWEB)

    Dublenich, L.B.; Gor' kov, A.P.

    1984-01-01

    The results are cited of an interval by interval analysis of the commercial drilling speeds in individual sites of the Carpathian region (Skhodnitsa, Dolina, Duvboshanka) which attest to the presence of reserves for increasing the commercial drilling speeds.

  15. Communication confidence in persons with aphasia.

    Science.gov (United States)

    Babbitt, Edna M; Cherney, Leora R

    2010-01-01

    Communication confidence is a construct that has not been explored in the aphasia literature. Recently, national and international organizations have endorsed broader assessment methods that address quality of life and include participation, activity, and impairment domains as well as psychosocial areas. Individuals with aphasia encounter difficulties in all these areas on a daily basis in living with a communication disorder. Improvements are often reflected in narratives that are not typically included in standard assessments. This article illustrates how a new instrument measuring communication confidence might fit into a broad assessment framework and discusses the interaction of communication confidence, autonomy, and self-determination for individuals living with aphasia.

  16. Sex-specific increase in the prevalence of atrial fibrillation (The Copenhagen City Heart Study)

    DEFF Research Database (Denmark)

    Friberg, Jens; Scharling, Henrik; Gadsbøll, Niels

    2003-01-01

    Atrial fibrillation (AF) is the most frequently encountered cardiac arrhythmia. It is a risk factor for stroke and premature death. We studied the temporal changes in the prevalence of AF from 1976 to 1994 in a random population aged 50 to 89 years. The prevalence of AF, diagnosed from electrocar.......4% in 1976 to 1978 (odds ratio [OR] 1.0, reference) to 1.9% in 1981 to 1983 (OR 1.6, 95% confidence interval [CI] 1.1 to 2.1), and to 3.3% in 1991 to 1994 (OR 2.3, 95% CI 1.6 to 3.4, p...

  17. Planning an Availability Demonstration Test with Consideration of Confidence Level

    Directory of Open Access Journals (Sweden)

    Frank Müller

    2017-08-01

    Full Text Available The full service life of a technical product or system is usually not completed after an initial failure. With appropriate measures, the system can be returned to a functional state. Availability is an important parameter for evaluating such repairable systems: Failure and repair behaviors are required to determine this availability. These data are usually given as mean value distributions with a certain confidence level. Consequently, the availability value also needs to be expressed with a confidence level. This paper first highlights the bootstrap Monte Carlo simulation (BMCS for availability demonstration and inference with confidence intervals based on limited failure and repair data. The BMCS enables point-, steady-state and average availability to be determined with a confidence level based on the pure samples or mean value distributions in combination with the corresponding sample size of failure and repair behavior. Furthermore, the method enables individual sample sizes to be used. A sample calculation of a system with Weibull-distributed failure behavior and a sample of repair times is presented. Based on the BMCS, an extended, new procedure is introduced: the “inverse bootstrap Monte Carlo simulation” (IBMCS to be used for availability demonstration tests with consideration of confidence levels. The IBMCS provides a test plan comprising the required number of failures and repair actions that must be observed to demonstrate a certain availability value. The concept can be applied to each type of availability and can also be applied to the pure samples or distribution functions of failure and repair behavior. It does not require special types of distribution. In other words, for example, a Weibull, a lognormal or an exponential distribution can all be considered as distribution functions of failure and repair behavior. After presenting the IBMCS, a sample calculation will be carried out and the potential of the BMCS and the IBMCS

  18. Expenditure, confidence, and Uncertainty: Identifying shocks to consumer confidence using daily data

    OpenAIRE

    Lachowska, Marta

    2013-01-01

    The importance of consumer confidence in stimulating economic activity is a disputed issue in macroeconomics. Do changes in confidence represent autonomous fluctuations in optimism, independent of information on economic fundamentals, or are they a reflection of economic news? I study this question by using high-frequency microdata on spending and consumer confidence, and I find that consumer confidence contains information relevant to predicting spending, independent from other indicators. T...

  19. Visualizing Neural Machine Translation Attention and Confidence

    Directory of Open Access Journals (Sweden)

    Rikters Matīss

    2017-10-01

    Full Text Available In this article, we describe a tool for visualizing the output and attention weights of neural machine translation systems and for estimating confidence about the output based on the attention.

  20. Observed confidence levels theory and application

    CERN Document Server

    Polansky, Alan M

    2007-01-01

    Illustrating a simple, novel method for solving an array of statistical problems, Observed Confidence Levels: Theory and Application describes the basic development of observed confidence levels, a methodology that can be applied to a variety of common multiple testing problems in statistical inference. It focuses on the modern nonparametric framework of bootstrap-based estimates, allowing for substantial theoretical development and for relatively simple solutions to numerous interesting problems. After an introduction, the book develops the theory and application of observed confidence levels for general scalar parameters, vector parameters, and linear models. It then examines nonparametric problems often associated with smoothing methods, including nonparametric density estimation and regression. The author also describes applications in generalized linear models, classical nonparametric statistics, multivariate analysis, and survival analysis as well as compares the method of observed confidence levels to...

  1. Weighting Mean and Variability during Confidence Judgments

    Science.gov (United States)

    de Gardelle, Vincent; Mamassian, Pascal

    2015-01-01

    Humans can not only perform some visual tasks with great precision, they can also judge how good they are in these tasks. However, it remains unclear how observers produce such metacognitive evaluations, and how these evaluations might be dissociated from the performance in the visual task. Here, we hypothesized that some stimulus variables could affect confidence judgments above and beyond their impact on performance. In a motion categorization task on moving dots, we manipulated the mean and the variance of the motion directions, to obtain a low-mean low-variance condition and a high-mean high-variance condition with matched performances. Critically, in terms of confidence, observers were not indifferent between these two conditions. Observers exhibited marked preferences, which were heterogeneous across individuals, but stable within each observer when assessed one week later. Thus, confidence and performance are dissociable and observers’ confidence judgments put different weights on the stimulus variables that limit performance. PMID:25793275

  2. How do risk attitudes affect measured confidence?

    OpenAIRE

    Zahra Murad; Chris Starmer; Martin Sefton

    2014-01-01

    We examine confidence in own absolute performance using two elicitation procedures: self-reported (non-incentivised) confidence and an incentivised procedure that elicits the certainty equivalent of a bet based on performance. The former procedure reproduces the "hard-easy effect" (overconfidence in easy tasks and underconfidence in hard tasks) found in a large number of studies using non-incentivised self-reports. The latter procedure produces general underconfidence, which is somewhat reduc...

  3. Confidence in value-based choice

    Science.gov (United States)

    De Martino, Benedetto; Fleming, Stephen M.; Garrett, Neil; Dolan, Raymond

    2013-01-01

    Summary Decisions are never perfect with confidence in one’s choices fluctuating over time. How subjective confidence and valuation of choice options interact at the level of brain and behavior is unknown. Using a dynamic model of the decision process we show that confidence reflects the evolution of a decision variable over time, explaining the observed relation between confidence, value, accuracy and reaction time. As predicted by our dynamic model, we show that an fMRI signal in human ventromedial prefrontal cortex (vmPFC) reflects both value comparison and confidence in the value comparison process. Crucially, individuals varied in how they related confidence to accuracy, allowing us to show that this introspective ability is predicted by a measure of functional connectivity between vmPFC and rostrolateral prefrontal cortex (rlPFC). Our findings provide a mechanistic link between noise in value comparison and metacognitive awareness of choice, enabling us both to want and to express knowledge of what we want. PMID:23222911

  4. Context influences interpretation of eyewitness confidence statements.

    Science.gov (United States)

    Cash, Daniella K; Lane, Sean M

    2017-04-01

    When an eyewitness makes an identification from a lineup, he or she is asked to provide a confidence statement to help jurors assess credibility. However, these are verbal statements and people must rely on metacognitive processes to correctly interpret them. Recently, Dodson and Dobolyi (2015) argued that a person's interpretation of a witness's verbal confidence is influenced by the diagnosticity of the features used to justify his or her identification. We tested this hypothesis in 2 experiments. Experiment 1 found that, relative to a confidence-only control, participants reduced their ratings of confidence when statements were justified using a facial feature that was shared by lineup members, but not when the feature was unique to the member chosen from the lineup. In Experiment 2, we found that participants integrated across the dimensions of witness confidence and accuracy, even when asked to make separate ratings. Altogether, the results suggest that people readily incorporate contextual information into their interpretations of witnesses' verbal expressions of confidence and evaluations of accuracy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Increasing Product Confidence-Shifting Paradigms.

    Science.gov (United States)

    Phillips, Marla; Kashyap, Vishal; Cheung, Mee-Shew

    2015-01-01

    Leaders in the pharmaceutical, medical device, and food industries expressed a unilateral concern over product confidence throughout the total product lifecycle, an unsettling fact for these leaders to manage given that their products affect the lives of millions of people each year. Fueled by the heparin incident of intentional adulteration in 2008, initial efforts for increasing product confidence were focused on improving the confidence of incoming materials, with a belief that supplier performance must be the root cause. As in the heparin case, concern over supplier performance extended deep into the supply chain to include suppliers of the suppliers-which is often a blind spot for pharmaceutical, device, and food manufacturers. Resolved to address the perceived lack of supplier performance, these U.S. Food and Drug Administration (FDA)-regulated industries began to adopt the supplier relationship management strategy, developed by the automotive industry, that emphasizes "management" of suppliers for the betterment of the manufacturers. Current product and supplier management strategies, however, have not led to a significant improvement in product confidence. As a result of the enduring concern by industry leaders over the lack of product confidence, Xavier University launched the Integrity of Supply Initiative in 2012 with a team of industry leaders and FDA officials. Through a methodical research approach, data generated by the pharmaceutical, medical device, and food manufacturers surprisingly pointed to themselves as a source of the lack of product confidence, and revealed that manufacturers either unknowingly increase the potential for error or can control/prevent many aspects of product confidence failure. It is only through this paradigm shift that manufacturers can work collaboratively with their suppliers as equal partners, instead of viewing their suppliers as "lesser" entities needing to be controlled. The basis of this shift provides manufacturers

  6. Income Differences in Smoking Prevalences in 245 Districts of South Korea: Patterns by Area Deprivation and Urbanity, 2008-2014

    Directory of Open Access Journals (Sweden)

    Ikhan Kim

    2017-03-01

    Full Text Available Objectives The aim of this study was to measure income differences in smoking prevalence at the district level and to investigate correlations among area deprivation, smoking prevalence, and income differences in smoking prevalence, stratified by urbanity. Methods Data were pooled from the Community Health Survey data of South Korea between 2008 and 2014. The age-standardized prevalence of smoking and its interquintile income differences were calculated. We conducted correlation analyses to investigate the association of the deprivation index with smoking prevalence and interquintile differences in smoking prevalence. Results Across 245 districts, the median prevalence of smoking in men was 45.9% (95% confidence interval [CI], 43.4 to 48.5%, with an interquartile range (IQR of 4.6% points. In women, the median prevalence was 3.0% (95% CI, 2.4 to 3.6% and IQR was 1.6% points. The median interquintile difference in smoking prevalence was 7.4% points (95% CI, 1.6 to 13.2% points in men and 2.7% points (95% CI, 0.5 to 4.9% points in women. The correlation coefficients for the association between the deprivation index and smoking prevalence was 0.58, 0.15, -0.22 in metropolitan, urban, and rural areas, respectively, among men, and 0.54, -0.33, -0.43 among women. No meaningful correlation was found between area deprivation and interquintile difference in smoking prevalence. The correlation between smoking prevalence and interquintile difference in smoking prevalence was more evident in women than in men. Conclusions This study provides evidence of geographical variations in smoking prevalence and interquintile difference in smoking prevalence. Neither smoking prevalence nor the deprivation index was closely correlated with interquintile income difference in smoking prevalence. Measuring inequalities in smoking prevalence is crucial to developing policies aimed at reducing inequalities in smoking.

  7. Income Differences in Smoking Prevalences in 245 Districts of South Korea: Patterns by Area Deprivation and Urbanity, 2008-2014.

    Science.gov (United States)

    Kim, Ikhan; Bahk, Jinwook; Yoon, Tae-Ho; Yun, Sung-Cheol; Khang, Young-Ho

    2017-03-01

    The aim of this study was to measure income differences in smoking prevalence at the district level and to investigate correlations among area deprivation, smoking prevalence, and income differences in smoking prevalence, stratified by urbanity. Data were pooled from the Community Health Survey data of South Korea between 2008 and 2014. The age-standardized prevalence of smoking and its interquintile income differences were calculated. We conducted correlation analyses to investigate the association of the deprivation index with smoking prevalence and interquintile differences in smoking prevalence. Across 245 districts, the median prevalence of smoking in men was 45.9% (95% confidence interval [CI], 43.4 to 48.5%), with an interquartile range (IQR) of 4.6% points. In women, the median prevalence was 3.0% (95% CI, 2.4 to 3.6%) and IQR was 1.6% points. The median interquintile difference in smoking prevalence was 7.4% points (95% CI, 1.6 to 13.2% points) in men and 2.7% points (95% CI, 0.5 to 4.9% points) in women. The correlation coefficients for the association between the deprivation index and smoking prevalence was 0.58, 0.15, -0.22 in metropolitan, urban, and rural areas, respectively, among men, and 0.54, -0.33, -0.43 among women. No meaningful correlation was found between area deprivation and interquintile difference in smoking prevalence. The correlation between smoking prevalence and interquintile difference in smoking prevalence was more evident in women than in men. This study provides evidence of geographical variations in smoking prevalence and interquintile difference in smoking prevalence. Neither smoking prevalence nor the deprivation index was closely correlated with interquintile income difference in smoking prevalence. Measuring inequalities in smoking prevalence is crucial to developing policies aimed at reducing inequalities in smoking.

  8. Confidence in biopreparedness authorities among Finnish conscripts.

    Science.gov (United States)

    Vartti, Anne-Marie; Aro, Arja R; Jormanainen, Vesa; Henriksson, Markus; Nikkari, Simo

    2010-08-01

    A large sample of Finnish military conscripts of the armored brigade were questioned on the extent to which they trusted the information given biopreparedness authorities (such as the police, military, health care, and public health institutions) and how confident they were in the authority's ability to protect the public during a potential infectious disease outbreak, from either natural or deliberate causes. Participants answered a written questionnaire during their initial health inspection in July 2007. From a total of 1,000 conscripts, 953 male conscripts returned the questionnaire. The mean sum scores for confidence in the information given to biopreparedness authorities and the media on natural and bioterrorism-related outbreaks (range = 0-30) were 20.14 (SD = 7.79) and 20.12 (SD = 7.69), respectively. Mean sum scores for the respondents' confidence in the ability of the biopreparedness authorities to protect the public during natural and bioterrorism-related outbreaks (range 0-25) were 16.04 (SD = 5.78) and 16.17 (SD = 5.89). Most respondents indicated that during a natural outbreak, they would have confidence in information provided by a health care institution such as central hospitals and primary health care centers, whereas in the case of bioterrorism, the respondents indicated that they would have confidence in the defense forces and central hospitals.

  9. Confidence-building and Canadian leadership

    International Nuclear Information System (INIS)

    Cleminson, F.R.

    1998-01-01

    Confidence-building has come into its own as a 'tool of choice' in facilitating the non-proliferation, arms control and disarmament (NACD) agenda, whether regional or global. From the Middle East Peace Process (MEPP) to the ASEAN Intersessional Group on Confidence-Building (ARF ISG on CBMS), confidence-building has assumed a central profile in regional terms. In the Four Power Talks begun in Geneva on December 9, 1997, the United States identified confidence-building as one of two subject areas for initial discussion as part of a structured peace process between North and South Korea. Thus, with CBMs assuming such a high profile internationally, it seems prudent for Canadians to pause and take stock of the significant role which Canada has already played in the conceptual development of the process over the last two decades. Since the Helsinki accords of 1975, Canada has developed a significant expertise in this area through an unbroken series of original, basic research projects. These have contributed to defining the process internationally from concept to implementation. Today, these studies represent a solid and unique Departmental investment in basic research from which to draw in meeting Canada's current commitments to multilateral initiatives in the area of confidence-building and to provide a 'step up' in terms of future-oriented leadership. (author)

  10. ADAM SMITH: THE INVISIBLE HAND OR CONFIDENCE

    Directory of Open Access Journals (Sweden)

    Fernando Luis, Gache

    2010-01-01

    Full Text Available In 1776 Adam Smith raised the matter that an invisible hand was the one which moved the markets to obtain its efficiency. Despite in the present paper we are going to raise the hypothesis, that this invisible hand is in fact the confidence that each person feels when he is going to do business. That in addition it is unique, because it is different from the confidence of the others and that is a variable nonlinear that essentially is ligatured to respective personal histories. For that we are going to take as its bases the paper by Leopoldo Abadía (2009, with respect to the financial economy crisis that happened in 2007-2008, to evidence the form in which confidence operates. Therefore the contribution that we hope to do with this paper is to emphasize that, the level of confidence of the different actors, is the one which really moves the markets, (therefore the economy and that the crisis of the subprime mortgages is a confidence crisis at world-wide level.

  11. Predicting fecal coliform using the interval-to-interval approach and SWAT in the Miyun watershed, China.

    Science.gov (United States)

    Bai, Jianwen; Shen, Zhenyao; Yan, Tiezhu; Qiu, Jiali; Li, Yangyang

    2017-06-01

    Pathogens in manure can cause waterborne-disease outbreaks, serious illness, and even death in humans. Therefore, information about the transformation and transport of bacteria is crucial for determining their source. In this study, the Soil and Water Assessment Tool (SWAT) was applied to simulate fecal coliform bacteria load in the Miyun Reservoir watershed, China. The data for the fecal coliform were obtained at three sampling sites, Chenying (CY), Gubeikou (GBK), and Xiahui (XH). The calibration processes of the fecal coliform were conducted using the CY and GBK sites, and validation was conducted at the XH site. An interval-to-interval approach was designed and incorporated into the processes of fecal coliform calibration and validation. The 95% confidence interval of the predicted values and the 95% confidence interval of measured values were considered during calibration and validation in the interval-to-interval approach. Compared with the traditional point-to-point comparison, this method can improve simulation accuracy. The results indicated that the simulation of fecal coliform using the interval-to-interval approach was reasonable for the watershed. This method could provide a new research direction for future model calibration and validation studies.

  12. Determination of confidence limits for experiments with low numbers of counts

    International Nuclear Information System (INIS)

    Kraft, R.P.; Burrows, D.N.; Nousek, J.A.

    1991-01-01

    Two different methods, classical and Bayesian, for determining confidence intervals involving Poisson-distributed data are compared. Particular consideration is given to cases where the number of counts observed is small and is comparable to the mean number of background counts. Reasons for preferring the Bayesian over the classical method are given. Tables of confidence limits calculated by the Bayesian method are provided for quick reference. 12 refs

  13. Disparities in Confidence to Manage Chronic Diseases in Men

    Directory of Open Access Journals (Sweden)

    Keith Elder

    2014-08-01

    Full Text Available Background: Chronic diseases are highly prevalent among men in the United States and chronic disease management is problematic for men, particularly for racial and ethnic minority men. Objectives: This study examined the association between health information seeking and confidence to manage chronic diseases among men. Methods: Study data were drawn from the 2007 Health Tracking Household Survey and analyzed using multiple binary logistic regressions. The analytical sample included 2,653 men, 18 years and older with a chronic illness. Results: Health information seeking was not associated with confidence to manage chronic illnesses. African-American men had lower odds than White men to agree to take actions to prevent symptoms with their health. Hispanic men had lower odds than White men to agree to tell a doctor concerns they have, even when not asked. Conclusions: Racial and ethnic minority men with a chronic condition appear to be less confident to manage their health compared to white men. Chronic disease management needs greater exploration to understand the best ways to help racial and ethnic minority men successfully manage their chronic condition.

  14. Prevalence of human immunodeficiency virus infection and associated risk factors among prison inmates in the City of Florianópolis

    Directory of Open Access Journals (Sweden)

    Mariano Felisberto

    Full Text Available Abstract INTRODUCTION This study aimed to estimate the prevalence of human immunodeficiency virus (HIV infection among prison inmates and to define the behavioral profile of infected individuals. METHODS: In total, 147 individuals were interviewed and provided biological material. The study population consisted of male individuals who presented at the health unit of the Florianopolis State Penitentiary. RESULTS: The prevalence of HIV infection was 2.1% (95% confidence interval, 0.4-5.8. With respect to the behavioral profile of individuals, no variable showed statistical significance. CONCLUSIONS: The prevalence of HIV infection among prison inmates was higher than that reported for the general population.

  15. Prevalence and associated risk factors of necrotic enteritis on broiler farms in the United Kingdom; a cross-sectional survey.

    Science.gov (United States)

    Hermans, P G; Morgan, K L

    2007-02-01

    In order to determine the prevalence and risk factors for necrotic enteritis in broilers, a cross-sectional survey was conducted among 857 farms, rearing broilers for nine UK poultry companies. The main data collection tool was a postal questionnaire directed at farm managers. Additional information on disease occurrence on the farm was collected from veterinary postmortem reports. The response rate to the questionnaire was 75%, ranging from 54% to 90% within companies. During 2001, 32.8% of the respondents indicated that they had observed a case of necrotic enteritis (95% confidence interval, 29.1 to 36.8) in at least one flock. The disease was most often reported during the months October to February. The point prevalence (necrotic enteritis occurrence in the most recently reared flock) reported by farm managers was 12.3% (95% confidence interval, 9.8 to 15.2). Multilevel logistic regression was performed with the poultry company as the random effect, using the occurrence of necrotic enteritis in the farm's most recently reared flock as the dependent variable. Strong associations were found between the outcome variable and the occurrence of wet litter (odds ratio, 2.39; 95% confidence interval, 1.27 to 4.52; P = 0.007) and coccidiosis (odds ratio, 4.68; 95% confidence interval, 1.74 to 12.55; P = 0.002). In addition, the use of ammonia as a disinfectant for coccidial oocysts appeared to be an independent risk factor (odds ratio, 3.44; 95% confidence interval, 1.53 to 7.71; P = 0.003). Finally, the positive association between the use of plasterboard walls in poultry houses and the occurrence of necrotic enteritis might point to an important role of cleaning and disinfection in the epidemiology of this disease (odds ratio, 3.72; 1.38 to 10.00; P = 0.009).

  16. Adaptive Confidence Bands for Nonparametric Regression Functions.

    Science.gov (United States)

    Cai, T Tony; Low, Mark; Ma, Zongming

    2014-01-01

    A new formulation for the construction of adaptive confidence bands in non-parametric function estimation problems is proposed. Confidence bands are constructed which have size that adapts to the smoothness of the function while guaranteeing that both the relative excess mass of the function lying outside the band and the measure of the set of points where the function lies outside the band are small. It is shown that the bands adapt over a maximum range of Lipschitz classes. The adaptive confidence band can be easily implemented in standard statistical software with wavelet support. Numerical performance of the procedure is investigated using both simulated and real datasets. The numerical results agree well with the theoretical analysis. The procedure can be easily modified and used for other nonparametric function estimation models.

  17. A systematic review of maternal confidence for physiologic birth: characteristics of prenatal care and confidence measurement.

    Science.gov (United States)

    Avery, Melissa D; Saftner, Melissa A; Larson, Bridget; Weinfurter, Elizabeth V

    2014-01-01

    Because a focus on physiologic labor and birth has reemerged in recent years, care providers have the opportunity in the prenatal period to help women increase confidence in their ability to give birth without unnecessary interventions. However, most research has only examined support for women during labor. The purpose of this systematic review was to examine the research literature for information about prenatal care approaches that increase women's confidence for physiologic labor and birth and tools to measure that confidence. Studies were reviewed that explored any element of a pregnant woman's interaction with her prenatal care provider that helped build confidence in her ability to labor and give birth. Timing of interaction with pregnant women included during pregnancy, labor and birth, and the postpartum period. In addition, we looked for studies that developed a measure of women's confidence related to labor and birth. Outcome measures included confidence or similar concepts, descriptions of components of prenatal care contributing to maternal confidence for birth, and reliability and validity of tools measuring confidence. The search of MEDLINE, CINAHL, PsycINFO, and Scopus databases provided a total of 893 citations. After removing duplicates and articles that did not meet inclusion criteria, 6 articles were included in the review. Three relate to women's confidence for labor during the prenatal period, and 3 describe tools to measure women's confidence for birth. Research about enhancing women's confidence for labor and birth was limited to qualitative studies. Results suggest that women desire information during pregnancy and want to use that information to participate in care decisions in a relationship with a trusted provider. Further research is needed to develop interventions to help midwives and physicians enhance women's confidence in their ability to give birth and to develop a tool to measure confidence for use during prenatal care. © 2014 by

  18. Confidence regions for fabric shape diagrams

    Science.gov (United States)

    Ringrose, Trevor J.; Benn, Douglas I.

    1997-12-01

    Fabric shape is often quantified using the three eigenvalues from the 'orientation tensor' method applied to a sample of directions. Several studies have used eigenvalues plotted on fabric shape diagrams to distinguish sedimentary facies or strain histories. However, such studies seldom consider how well the sample eigenvalues represent the true fabric shape. In this paper, we use 'bootstrapping' techniques to define confidence regions for sample eigenvalues, and show that sample and population eigenvalues may differ substantially. Confidence regions are often very large for small sample sizes, and we recommend that sample sizes should be at least 50.

  19. Asymptotically Honest Confidence Regions for High Dimensional

    DEFF Research Database (Denmark)

    Caner, Mehmet; Kock, Anders Bredahl

    While variable selection and oracle inequalities for the estimation and prediction error have received considerable attention in the literature on high-dimensional models, very little work has been done in the area of testing and construction of confidence bands in high-dimensional models. However...... of the asymptotic covariance matrix of an increasing number of parameters which is robust against conditional heteroskedasticity. To our knowledge we are the first to do so. Next, we show that our confidence bands are honest over sparse high-dimensional sub vectors of the parameter space and that they contract...

  20. The prevalence of metabolic syndrome in Danish patients with HIV infection: the effect of antiretroviral therapy

    DEFF Research Database (Denmark)

    Hansen, B R; Petersen, J; Haugaard, S B

    2009-01-01

    OBJECTIVES: The prevalence of metabolic syndrome (MS) in HIV-infected patients on highly active antiretroviral therapy (HAART) is a subject of debate. We investigated the prevalence of MS in a cohort of Danish HIV-infected patients and estimated the effect of the various classes of antiretroviral...... Education Programme (NCEP) Adult Treatment Panel (ATP) III diagnostic criteria. RESULTS: Five hundred and sixty-six patients were included in the study, of whom 27% were diagnosed with MS. In univariate analysis, the duration of treatment with different drug classes was associated with the prevalence of MS......% confidence interval (CI) 1.73-6.74; and OR 1.96, 95% CI 1.19-3.22, respectively]. CONCLUSIONS: MS is prevalent in HIV-infected Danes. However, treatment with specific drug classes does not seem to confer an elevated risk for MS, other than the risk conferred by known acute effects on triglycerides....

  1. Prevalence of undiagnosed acute and chronic HIV in a lower-prevalence urban emergency department.

    Science.gov (United States)

    Moschella, Phillip C; Hart, Kimberly W; Ruffner, Andrew H; Lindsell, Christopher J; Wayne, D Beth; Sperling, Matthew I; Trott, Alexander T; Fichtenbaum, Carl J; Lyons, Michael S

    2014-09-01

    We estimated the seroprevalence of both acute and chronic HIV infection by using a random sample of emergency department (ED) patients from a region of the United States with low-to-moderate HIV prevalence. This cross-sectional seroprevalence study consecutively enrolled patients aged 18 to 64 years within randomly selected sampling blocks in a Midwestern urban ED in a region of lower HIV prevalence in 2008 to 2009. Participants were compensated for providing a blood sample and health information. After de-identification, we assayed samples for HIV antibody and nucleic acid. There were 926 participants who consented and enrolled. Overall, prevalence of undiagnosed HIV was 0.76% (95% confidence interval [CI] = 0.30%, 1.56%). Three participants (0.32%; 95% CI = 0.09%, 0.86%) were nucleic acid-positive but antibody-negative and 4 (0.43%; 95% CI = 0.15%, 1.02%) were antibody-positive. Even when the absolute prevalence is low, a considerable proportion of undetected HIV cases in an ED population are acute. Identification of acute HIV in ED settings should receive increased priority.

  2. Prevalence of Undiagnosed Acute and Chronic HIV in a Lower-Prevalence Urban Emergency Department

    Science.gov (United States)

    Moschella, Phillip C.; Hart, Kimberly W.; Ruffner, Andrew H.; Lindsell, Christopher J.; Wayne, D. Beth; Sperling, Matthew I.; Trott, Alexander T.; Fichtenbaum, Carl J.

    2014-01-01

    Objectives. We estimated the seroprevalence of both acute and chronic HIV infection by using a random sample of emergency department (ED) patients from a region of the United States with low-to-moderate HIV prevalence. Methods. This cross-sectional seroprevalence study consecutively enrolled patients aged 18 to 64 years within randomly selected sampling blocks in a Midwestern urban ED in a region of lower HIV prevalence in 2008 to 2009. Participants were compensated for providing a blood sample and health information. After de-identification, we assayed samples for HIV antibody and nucleic acid. Results. There were 926 participants who consented and enrolled. Overall, prevalence of undiagnosed HIV was 0.76% (95% confidence interval [CI] = 0.30%, 1.56%). Three participants (0.32%; 95% CI = 0.09%, 0.86%) were nucleic acid–positive but antibody-negative and 4 (0.43%; 95% CI = 0.15%, 1.02%) were antibody-positive. Conclusions. Even when the absolute prevalence is low, a considerable proportion of undetected HIV cases in an ED population are acute. Identification of acute HIV in ED settings should receive increased priority. PMID:25033145

  3. Distinguishing highly confident accurate and inaccurate memory: insights about relevant and irrelevant influences on memory confidence

    Science.gov (United States)

    Chua, Elizabeth F.; Hannula, Deborah E.; Ranganath, Charan

    2012-01-01

    It is generally believed that accuracy and confidence in one’s memory are related, but there are many instances when they diverge. Accordingly, it is important to disentangle the factors which contribute to memory accuracy and confidence, especially those factors that contribute to confidence, but not accuracy. We used eye movements to separately measure fluent cue processing, the target recognition experience, and relative evidence assessment on recognition confidence and accuracy. Eye movements were monitored during a face-scene associative recognition task, in which participants first saw a scene cue, followed by a forced-choice recognition test for the associated face, with confidence ratings. Eye movement indices of the target recognition experience were largely indicative of accuracy, and showed a relationship to confidence for accurate decisions. In contrast, eye movements during the scene cue raised the possibility that more fluent cue processing was related to higher confidence for both accurate and inaccurate recognition decisions. In a second experiment, we manipulated cue familiarity, and therefore cue fluency. Participants showed higher confidence for cue-target associations for when the cue was more familiar, especially for incorrect responses. These results suggest that over-reliance on cue familiarity and under-reliance on the target recognition experience may lead to erroneous confidence. PMID:22171810

  4. Evaluating Measures of Optimism and Sport Confidence

    Science.gov (United States)

    Fogarty, Gerard J.; Perera, Harsha N.; Furst, Andrea J.; Thomas, Patrick R.

    2016-01-01

    The psychometric properties of the Life Orientation Test-Revised (LOT-R), the Sport Confidence Inventory (SCI), and the Carolina SCI (CSCI) were examined in a study involving 260 athletes. The study aimed to test the dimensional structure, convergent and divergent validity, and invariance over competition level of scores generated by these…

  5. Coping under pressure: Strategies for maintaining confidence ...

    African Journals Online (AJOL)

    2010-08-11

    Aug 11, 2010 ... Coping under pressure: Strategies for maintaining confidence amongst South African soccer coaches. Authors: Jhalukpreya Surujlal1. Sheila Nguyen2. Affiliations: 1Faculty of Management. Sciences, Vaal University of. Technology, South Africa. 2Faculty of Business and Law, School of. Management and.

  6. Growing confidence, building skills | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    For two-time Research Award recipient (2012 and 2014) Ahmed Rashid, his IDRC experience “gave me the confidence to conduct high quality research in social sciences.” In 2012 Rashid explored the influence of think tanks on policy in Bangladesh, as well as their relationships with international donors and media.

  7. Detecting Disease in Radiographs with Intuitive Confidence

    Directory of Open Access Journals (Sweden)

    Stefan Jaeger

    2015-01-01

    Full Text Available This paper argues in favor of a specific type of confidence for use in computer-aided diagnosis and disease classification, namely, sine/cosine values of angles represented by points on the unit circle. The paper shows how this confidence is motivated by Chinese medicine and how sine/cosine values are directly related with the two forces Yin and Yang. The angle for which sine and cosine are equal (45° represents the state of equilibrium between Yin and Yang, which is a state of nonduality that indicates neither normality nor abnormality in terms of disease classification. The paper claims that the proposed confidence is intuitive and can be readily understood by physicians. The paper underpins this thesis with theoretical results in neural signal processing, stating that a sine/cosine relationship between the actual input signal and the perceived (learned input is key to neural learning processes. As a practical example, the paper shows how to use the proposed confidence values to highlight manifestations of tuberculosis in frontal chest X-rays.

  8. Validity and Reliability Consequences of Confidence Weighting

    Science.gov (United States)

    Hopkins, Kenneth D.; And Others

    1973-01-01

    Study was designed to provide some indication as to whether the gain in test reliability from confidence scoring results from relevant or irrelevant sources. If the increase in reliability is the result of a gambling response style, it is conceivable that validity could actually decrease even though reliability is increased. (Authors/CB)

  9. Diagnosing dementia with confidence by GPs.

    NARCIS (Netherlands)

    Hout, H.P.J. van; Vernooij-Dassen, M.J.F.J.; Stalman, W.A.B.

    2007-01-01

    BACKGROUND: Earlier reports suggest limited clinical reasoning and substantial uncertainty of GPs in assessing patients suspected of dementia. OBJECTIVE: To explore the predictors of GPs to decide on the presence and absence of dementia as well as the predictors of diagnostic confidence of GPs.

  10. The confidence effects of fiscal consolidations

    NARCIS (Netherlands)

    Beetsma, R.M.W.J.; Cimadomo, J.; Furtuna, O.; Giuliodori, M.

    2014-01-01

    We explore how fiscal consolidations affect private sector confidence, a possible channel for the fiscal transmission that has received particular attention recently as a result of governments embarking on austerity trajectories in the aftermath of the crisis. Panel regressions based on the

  11. Observed Consultation: Confidence and Accuracy of Assessors

    Science.gov (United States)

    Tweed, Mike; Ingham, Christopher

    2010-01-01

    Judgments made by the assessors observing consultations are widely used in the assessment of medical students. The aim of this research was to study judgment accuracy and confidence and the relationship between these. Assessors watched recordings of consultations, scoring the students on: a checklist of items; attributes of consultation; a…

  12. Principles of psychological confidence of NPP operators

    International Nuclear Information System (INIS)

    Alpeev, A.S.

    1994-01-01

    The problems of operator interaction with subsystems supporting his activity are discussed from the point of view of formation of his psychological confidence on the basis of the automation intellectual means capabilities. The functions of operator activity supporting subsystems, which realization will provide to decrease greatly the portion of accidents at NPPs connected with mistakes in operator actions, are derived. 6 refs

  13. The Confidence Factor in Liberal Education

    Science.gov (United States)

    Gordon, Daniel

    2012-01-01

    With the US unemployment rate at 9 percent, it's rational for college students to lose confidence in the liberal arts and to opt for a vocational major. Or is it? There is a compelling economic case for the liberal arts. Against those who call for more professional training, liberal educators should concede nothing. However, they do have a…

  14. The confidence effects of fiscal consolidations

    NARCIS (Netherlands)

    Beetsma, R.; Cimadomo, J.; Furtuna, O.; Giuliodori, M.

    2015-01-01

    We explore how fiscal consolidations affect private sector confidence, a possible channel for the transmission of fiscal policy that has received particular attention recently as a result of governments embarking on austerity trajectories in the aftermath of the crisis. Panel regressions based on

  15. A Confidence Paradigm for Classification Systems

    Science.gov (United States)

    2008-09-01

    some of the overall vocabulary of ATR as well as an object-taxonomy. Fenton and Wang [20] state that classical multi-criteria decision making ( MCDM ...paper intro- duces general fuzzy MCDM problem. The authors state that they believe risk and confidence are the two dimensions in which the DM’s

  16. Toward a Theory of Assurance Case Confidence

    Science.gov (United States)

    2012-09-01

    Toward a Theory of Assurance Case Confidence John B. Goodenough Charles B. Weinstock Ari Z. Klein September 2012 TECHNICAL REPORT...6. AUTHOR(S) John B. Goodenough , Charles B. Weinstock, Ari Z. Klein 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Software Engineering

  17. Coverage Probability of Random Intervals

    OpenAIRE

    Chen, Xinjia

    2007-01-01

    In this paper, we develop a general theory on the coverage probability of random intervals defined in terms of discrete random variables with continuous parameter spaces. The theory shows that the minimum coverage probabilities of random intervals with respect to corresponding parameters are achieved at discrete finite sets and that the coverage probabilities are continuous and unimodal when parameters are varying in between interval endpoints. The theory applies to common important discrete ...

  18. The longitudinal association of marital confidence, time spent together, and marital satisfaction.

    Science.gov (United States)

    Johnson, Matthew D; Anderson, Jared R

    2013-06-01

    Using three waves of dyadic data collected at 18-month intervals from a community-based sample of 610 newly married heterosexual couples (1 220 individuals), we examined the relationship between marital confidence, time spent together, and marital satisfaction using a modified actor-partner interdependence model. Results indicate that after controlling for marital satisfaction and time spent together at Time 1, marital confidence around the time of marriage was associated with marital satisfaction approximately 3 years later. In addition, marital confidence was associated with how much time husbands and wives spent together at Time 2, which was related to marital satisfaction at Time 3. Tests of the mediating paths from marital confidence to marital satisfaction trended toward significance. The results suggest the importance of assessing for relationship confidence when working with couples in the early stages of their relationship. © FPI, Inc.

  19. Support Vector Regression with Interval-Input Interval-Output

    Directory of Open Access Journals (Sweden)

    Wensen An

    2008-12-01

    Full Text Available Support vector machines (classification and regression are powerful machine learning techniques for crisp data. In this paper, the problem is considered for interval data. Two methods to deal with the problem using support vector regression are proposed and two new methods for evaluating performance for estimating prediction interval are presented as well.

  20. Interval Entropy and Informative Distance

    Directory of Open Access Journals (Sweden)

    Fakhroddin Misagh

    2012-03-01

    Full Text Available The Shannon interval entropy function as a useful dynamic measure of uncertainty for two sided truncated random variables has been proposed in the literature of reliability. In this paper, we show that interval entropy can uniquely determine the distribution function. Furthermore, we propose a measure of discrepancy between two lifetime distributions at the interval of time in base of Kullback-Leibler discrimination information. We study various properties of this measure, including its connection with residual and past measures of discrepancy and interval entropy, and we obtain its upper and lower bounds.

  1. Building Public Confidence in Nuclear Activities

    International Nuclear Information System (INIS)

    Isaacs, T

    2002-01-01

    Achieving public acceptance has become a central issue in discussions regarding the future of nuclear power and associated nuclear activities. Effective public communication and public participation are often put forward as the key building blocks in garnering public acceptance. A recent international workshop in Finland provided insights into other features that might also be important to building and sustaining public confidence in nuclear activities. The workshop was held in Finland in close cooperation with Finnish stakeholders. This was most appropriate because of the recent successes in achieving positive decisions at the municipal, governmental, and Parliamentary levels, allowing the Finnish high-level radioactive waste repository program to proceed, including the identification and approval of a proposed candidate repository site. Much of the workshop discussion appropriately focused on the roles of public participation and public communications in building public confidence. It was clear that well constructed and implemented programs of public involvement and communication and a sense of fairness were essential in building the extent of public confidence needed to allow the repository program in Finland to proceed. It was also clear that there were a number of other elements beyond public involvement that contributed substantially to the success in Finland to date. And, in fact, it appeared that these other factors were also necessary to achieving the Finnish public acceptance. In other words, successful public participation and communication were necessary but not sufficient. What else was important? Culture, politics, and history vary from country to country, providing differing contexts for establishing and maintaining public confidence. What works in one country will not necessarily be effective in another. Nonetheless, there appear to be certain elements that might be common to programs that are successful in sustaining public confidence and some of

  2. Building Public Confidence in Nuclear Activities

    International Nuclear Information System (INIS)

    Isaacs, T

    2002-01-01

    Achieving public acceptance has become a central issue in discussions regarding the future of nuclear power and associated nuclear activities. Effective public communication and public participation are often put forward as the key building blocks in garnering public acceptance. A recent international workshop in Finland provided insights into other features that might also be important to building and sustaining public confidence in nuclear activities. The workshop was held in Finland in close cooperation with Finnish stakeholders. This was most appropriate because of the recent successes in achieving positive decisions at the municipal, governmental, and Parliamentary levels, allowing the Finnish high-level radioactive waste repository program to proceed, including the identification and approval of a proposed candidate repository site Much of the workshop discussion appropriately focused on the roles of public participation and public communications in building public confidence. It was clear that well constructed and implemented programs of public involvement and communication and a sense of fairness were essential in building the extent of public confidence needed to allow the repository program in Finland to proceed. It was also clear that there were a number of other elements beyond public involvement that contributed substantially to the success in Finland to date. And, in fact, it appeared that these other factors were also necessary to achieving the Finnish public acceptance. In other words, successful public participation and communication were necessary but not sufficient. What else was important? Culture, politics, and history vary from country to country, providing differing contexts for establishing and maintaining public confidence. What works in one country will not necessarily be effective in another. Nonetheless, there appear to be certain elements that might be common to programs that are successful in sustaining public confidence, and some of

  3. Lumbar spondylolisthesis among elderly men: prevalence, correlates and progression

    Science.gov (United States)

    Denard, Patrick J.; Holton, Kathleen F.; Miller, Jessica; Fink, Howard A.; Kado, Deborah M.; Yoo, Jung U.; Marshall, Lynn M.

    2010-01-01

    Study Design Prospective cohort study. Objective Estimate the prevalence of spondylolisthesis and determine the factors associated with higher or lower prevalence among men aged 65 years or older. Summary of Background Data Spondylolisthesis prevalence is reported to increase with age and to be higher among women than men. Among women aged ≥65 years, prevalence was estimated to be 29%, but no estimates among men of this age have been reported. Methods Lateral lumbar spine radiographs were obtained at baseline and a follow-up visit in the Osteoporotic Fractures in Men (MrOS) study, a cohort of community dwelling men ages ≥ 65 years. Average time between radiographs was 4.6 (±0.4) years. For the present study, 300 men were sampled at random at baseline. Of these, 295 had a usable baseline radiograph; 190 surviving participants had a follow-up radiograph. Spondylolisthesis was defined as a forward slip ≥ 5%. Progression was defined as a 5% increase in slip severity on the follow-up radiograph. Associations of spondylolisthesis prevalence with baseline characteristics were estimated with age-adjusted prevalence ratios and 95% confidence intervals from log binomial regression models. Results The mean (sd) age of the men studied was 74 (±6) years. Prevalence of lumbar spondylolisthesis was 31%. Spondylolisthesis was observed at the L3/4, L4/5, and L5/S1 levels. In 96% with spondylolisthesis, only one vertebral level was involved. The degree of slip ranged from 5%–28%, and nearly all listhesis was classified as Meyerding grade I. During follow-up, 12% of men with prevalent spondylolisthesis had progression; 12% without baseline spondylolisthesis had new onset. Prevalence did not vary by height, BMI, smoking history, diabetes, or heart disease. However, men with spondylolisthesis more often reported higher levels of physical activity or walking daily for exercise than men without spondylolisthesis. Conclusions Spondylolisthesis may be more common among older men

  4. Prevalence of musculoskeletal disorders among farmers: A systematic review.

    Science.gov (United States)

    Osborne, Aoife; Blake, Catherine; Fullen, Brona M; Meredith, David; Phelan, James; McNamara, John; Cunningham, Caitriona

    2012-02-01

    To determine the prevalence of musculoskeletal disorders (MSDs) among farmers and to establish the most common regional MSDs reported. Comprehensive electronic searches of Pubmed, Web of Science, CINAHL, SCOPUS, EMBASE, Agris Database, and Cochrane Library were carried out using keywords for MSDs and farmers. Pooled estimates of prevalence with 95% confidence intervals were calculated for overall MSD prevalence and the most common regional MSDs reported. Twenty-four studies fulfilled the inclusion criteria and were incorporated into this review. From these studies, life-time prevalence of any form of MSD among farmers was 90.6% while 1-year MSD prevalence was 76.9% (95% CI 69.8-82.7). The majority of studies focused on spinal MSDs with low back pain (LBP) the most frequently investigated. Life-time LBP prevalence was 75% (95% CI 67-81.5) while 1-year LBP prevalence was 47.8% (95% CI 40.2-55.5). The next most common regional MSDs reported were upper (range 3.6-71.4%) and lower extremities (range 10.4-41%). The systematic review identified the prevalence of MSDs by body region in farmers and established that LBP was the most common MSD, followed by upper and then lower extremity MSDs. Reported trends suggest that the prevalence of MSDs in farmers is greater than in non-farmer populations. Case-definition uniformity among MSD researchers is warranted. More studies are needed regarding upper and lower extremity MSDs, gender, workplace, and task context of MSDs. Copyright © 2011 Wiley Periodicals, Inc.

  5. The Effect of Adaptive Confidence Strategies in Computer-Assisted Instruction on Learning and Learner Confidence

    Science.gov (United States)

    Warren, Richard Daniel

    2012-01-01

    The purpose of this research was to investigate the effects of including adaptive confidence strategies in instructionally sound computer-assisted instruction (CAI) on learning and learner confidence. Seventy-one general educational development (GED) learners recruited from various GED learning centers at community colleges in the southeast United…

  6. Graphical interpretation of confidence curves in rankit plots

    DEFF Research Database (Denmark)

    Hyltoft Petersen, Per; Blaabjerg, Ole; Andersen, Marianne

    2004-01-01

    distribution and the percentage of cumulative points exceeding these limits. The process is to rank the reference values and plot the cumulative frequency points in a rankit plot with a logarithmic (In=log(e)) transformed abscissa. If the distribution is close to In-Gaussian the cumulative frequency points......-Gaussian distributions of subgroups of reference values from healthy individuals is presented. In addition, distributions of values from well-defined diseased individuals may show up as In-Gaussian. It is evident from the examples that the rankit transformation and simple graphical evaluation for non......A well-known transformation from the bell-shaped Gaussian (normal) curve to a straight line in the rankit plot is investigated, and a tool for evaluation of the distribution of reference groups is presented. It is based on the confidence intervals for percentiles of the calculated Gaussian...

  7. Automatic Error Analysis Using Intervals

    Science.gov (United States)

    Rothwell, E. J.; Cloud, M. J.

    2012-01-01

    A technique for automatic error analysis using interval mathematics is introduced. A comparison to standard error propagation methods shows that in cases involving complicated formulas, the interval approach gives comparable error estimates with much less effort. Several examples are considered, and numerical errors are computed using the INTLAB…

  8. Stakeholder confidence and radioactive waste disposal

    International Nuclear Information System (INIS)

    2000-01-01

    Any significant decisions regarding geologic disposal of radioactive waste will need a comprehensive public review and a thorough involvement of all relevant stakeholders, such as waste generators, waste management agencies, regulatory authorities, local communities and elected officials. The participation of non-technical stakeholders will become increasingly important as more countries move towards siting and implementing geologic repositories. The decision-making process and avenues for stakeholder involvement differ from country to country. It is important to identify similarities and differences, understand the key concerns of the various stakeholders, and develop means to interact effectively. The Nuclear Energy Agency recently set up a Forum on Stakeholder Confidence charged with distilling the lessons that can be learnt from national and international experience. These proceedings of the Forums first workshop held in August 2000 provide an overview of OECD countries' experience in the field of stakeholder confidence and radioactive waste disposal. (author)

  9. Confidence leak in perceptual decision-making

    Science.gov (United States)

    Rahnev, Dobromir; Koizumi, Ai; McCurdy, Li Yan; D’Esposito, Mark; Lau, Hakwan

    2015-01-01

    We live in a continuous environment in which the visual scene changes on a slow timescale. It has been shown that, to exploit such environmental stability, the brain creates a “continuity field” such that objects seen seconds ago influence the perception of current objects. What is unknown is whether a similar mechanism exists at the level of our metacognitive representations. In three experiments we demonstrate a robust inter-task “confidence leak” that cannot be explained by response priming or attentional fluctuations. Observers’ ability to modulate this confidence leak predicted higher capacity for metacognition as well as greater gray matter volume in the prefrontal cortex. A model based on normative principles from Bayesian inference explained the results by postulating that observers subjectively estimate the perceptual signal strength in a stable environment. These results point to the existence of a novel metacognitive mechanism mediated by regions in prefrontal cortex. PMID:26408037

  10. Self-reported diabetes in older people: comparison of prevalences and control measures

    Directory of Open Access Journals (Sweden)

    Sheila Rizzato Stopa

    2014-08-01

    Full Text Available OBJECTIVE The objective of this study was to analyze the prevalence of diabetes in older people and the adopted control measures. METHODS Data regarding older diabetic individuals who participated in the Health Surveys conducted in the Municipality of Sao Paulo, SP, ISA-Capital, in 2003 and 2008, which were cross-sectional studies, were analyzed. Prevalences and confidence intervals were compared between 2003 and 2008, according to sociodemographic variables. The combination of the databases was performed when the confidence intervals overlapped. The Chi-square (level of significance of 5% and the Pearson’s Chi-square (Rao-Scott tests were performed. The variables without overlap between the confidence intervals were not tested. RESULTS The age of the older adults was 60-69 years. The majority were women, Caucasian, with an income of between > 0.5 and 2.5 times the minimum salary and low levels of schooling. The prevalence of diabetes was 17.6% (95%CI 14.9;20.6 in 2003 and 20.1% (95%CI 17.3;23.1 in 2008, which indicates a growth over this period (p at the limit of significance. The most prevalent measure adopted by the older adults to control diabetes was hypoglycemic agents, followed by diet. Physical activity was not frequent, despite the significant differences observed between 2003 and 2008 results. The use of public health services to control diabetes was significantly higher in older individuals with lower income and lower levels of education. CONCLUSIONS Diabetes is a complex and challenging disease for patients and the health systems. Measures that encourage health promotion practices are necessary because they presented a smaller proportion than the use of hypoglycemic agents. Public health policies should be implemented, and aimed mainly at older individuals with low income and schooling levels. These changes are essential to improve the health condition of older diabetic patients.

  11. Modeling the Effects of Diversity Experiences and Multiple Capitals on Latina/o College Students' Academic Self-Confidence

    Science.gov (United States)

    Nunez, Anne-Marie

    2009-01-01

    This study develops a model predicting academic self-confidence for 2nd-year Latina/o college students. Findings indicate that forms of academic, cultural, social, and intercultural capital (the capacity to negotiate diverse racial and ethnic environments) are positively associated with academic self-confidence. The prevalence of negative…

  12. Comparison of prevalence rates of strabismus and amblyopia in Japanese elementary school children between the years 2003 and 2005.

    Science.gov (United States)

    Matsuo, Toshihiko; Matsuo, Chie

    2007-12-01

    We previously revealed the prevalence of strabismus and amblyopia in elementary school children between 6 and 12 years of age in Japan in the year 2003. Questionnaires asking the number of children with different types of strabismus and amblyopia were sent to all elementary schools in Okayama Prefecture in the year 2005, and the results in the year 2005 were compared with those obtained in the year 2003. The number of children covered by the return of questionnaires was 84,619 (74%) of 113,763 total pupils, including grades 1 to 6, in Okayama Prefecture in the year 2005. The total numbers of children with strabismus and amblyopia, including grades 1 to 6, were 844 (0.99%, 95% confidence interval: 0.94-1.06%) and 173 (0.20%, 95% confidence interval: 0.17-0.23%), respectively. The numbers of children with any type of exotropia and any type of esotropia were 524 (0.62%) and 187(0.22%), respectively. In the previous survey conducted in 2003, the number of children covered by the return of questionnaires was 86,531 (76%) of 113,254 total pupils. The total numbers of children with strabismus and amblyopia were 1,112 (1.28%, 95% confidence interval: 1.24-1.36%) and 125 (0.14%, 95% confidence interval: 0.12-0.17%), respectively. The numbers of children with any types of exotropia and esotropia were 602 (0.69) and 245 (0.28%), respectively. The prevalence of strabismus in this large population of Japanese elementary school children was significantly different between the years 2003 and 2005, while the prevalence of amblyopia was similar between the years.

  13. Period prevalence and reporting rate of medication errors among nurses in Iran: A systematic review and meta-analysis.

    Science.gov (United States)

    Matin, Behzad Karami; Hajizadeh, Mohammad; Nouri, Bijan; Rezaeian, Shahab; Mohammadi, Masoud; Rezaei, Satar

    2018-01-22

    To estimate the 1-year period prevalence of medication errors and the reporting rate to nurse managers among nurses working in hospitals in Iran. Medication errors are one of the main factors affecting the quality of hospital services and reducing patient safety in health care systems. A literature search from Iranian and international scientific databases was developed to find relevant studies. Meta-regression was used to identify which characteristics may have a confounding effect on the pooled prevalence estimates. Based on the final 22 studies with 3556 samples, the overall estimated 1-year period prevalence of medication errors and its reporting rate to nurse managers among nurses were 53% (95% confidence interval, 41%-60%) and 36% (95% confidence interval, 23%-50%), respectively. The meta-regression analyses indicated that the sex (female/male) ratio was a statistically significant predictor of the prevalence of medication errors (p medication errors to nurse managers. The period prevalence of medication errors among nurses working in hospitals was high in Iran, whereas its reporting rate to nurse managers was low. Continuous training programmes are required to reduce and prevent medication errors among nursing staff and to improve the reporting rate to nurse managers in in Iran. © 2018 John Wiley & Sons Ltd.

  14. Prevalence of Lebanese stroke survivors: A comparative pilot study

    Directory of Open Access Journals (Sweden)

    Nathalie Lahoud

    2016-09-01

    Full Text Available Stroke is a leading cause of morbidity and mortality worldwide and its late burden has mainly been attributable to developing countries. Lebanon is one of these countries where epidemiological studies on stroke burden are scarce but necessary. Thus, the present study was conducted to assess the prevalence of stroke survivors among Lebanese inhabitants. A cross-sectional survey was carried out using randomly selected landline phone numbers on all governorates to retrieve data on stroke survivors and their sociodemographic characteristics. Results were then standardized over the Lebanese and the World Health Organization (WHO world populations. A total of 6963 Lebanese inhabitants were included in the study; among these were 56 stroke survivors. This led to an adjusted stroke prevalence of 0.50% [95% confidence interval (CI = 0.33–0.66%] and a world-standardized prevalence of 0.60% (95% CI = 0.42–0.78%. A significantly higher stroke prevalence was found among older age groups and more socioeconomically privileged areas. Overall, the study showed a relatively higher prevalence of stroke in this sample of Lebanese inhabitants when compared to other developing countries. However, larger community-based studies with a clinical assessment of stroke cases are needed to confirm our findings.

  15. The incidence and clinical associated factors of interval colorectal cancers in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Cheng-En Tsai

    2018-03-01

    Conclusion: The prevalence of interval CRC in the present study is 3.28%. Comorbidity with ESRD and shorter ascending colon withdrawal time could be factors associated with interval CRC. Good colon preparation for the patients with ESRD and more ascending colon withdrawal time could reduce the interval CRC.

  16. International Confidence in Italian Economy. A Spread and Gambling Analysis

    Directory of Open Access Journals (Sweden)

    Murgea Aurora

    2015-03-01

    Full Text Available Gambling is an ancient human activity with a prevalent position nowadays both as a social entertainment activity and as a way to gain money effortless. Every country has its specific pattern in gambling determined both by its cultural and macroeconomic determinants and by its national regulatory framework. Macroeconomic variables as gross national income per capita, annual variation of GDP or unemployment were previously proved to be connected with the gambling industry. The aim of this paper is to analyze the effects generated by the internal and external loss of confidence in the Italian economy, as an effect of the latest financial crisis, over the Italian gambling industry. The level of spread between the 10 years yield of Italian and German government bonds is used as a proxy for the international trust in the Italian economy and the Economic Sentiment Indicator is used to describe the Italian citizens' confidence. The main results show a strong positive, statistically significant correlation between skill games and spread and an unexpected negative significant correlations between spread and lottery, one of the purely fortune games that was often seen as an ultimate chance to survive the crisis. The Economic Sentiment Indicator seems not to be correlated with any of the gambling categories.

  17. No association between gender inequality and peak HIV prevalence in developing countries - an ecological study.

    Science.gov (United States)

    Kenyon, Chris R; Buyze, Jozefien

    2015-01-01

    The prevalence of both gender inequality and HIV prevalence vary considerably both within all developing countries and within those in sub-Saharan Africa. We test the hypothesis that the extent of gender inequality is associated with national peak HIV prevalence. Linear regression was used to test the association between national peak HIV prevalence and three markers of gender equality - the gender-related development index (GDI), the gender empowerment measure (GEM), and the gender inequality index (GII). No evidence was found of a positive relationship between gender inequality and HIV prevalence, either in the analyses of all developing countries or those limited to Africa. In the bivariate analyses limited to Africa, there was a positive association between the two measures of gender "equality" and peak HIV prevalence (GDI: coefficient 28, 95% confidence interval (CI) 9.1-46.8; GEM: coefficient 54.8, 95% CI 20.5-89.1). There was also a negative association between the marker of gender "inequality" and peak HIV prevalence (GII: coefficient -66.9, 95% CI -112.8 to -21.0). These associations all disappeared on multivariate analyses. We could not find any evidence to support the hypothesis that variations in the extent of gender inequality explain variations in HIV prevalence in developing countries.

  18. Transparency as an element of public confidence

    International Nuclear Information System (INIS)

    Kim, H.K.

    2007-01-01

    In the modern society, there is increasing demands for greater transparency. It has been discussed with respect to corruption or ethics issues in social science. The need for greater openness and transparency in nuclear regulation is widely recognised as public expectations on regulator grow. It is also related to the digital and information technology that enables disclosures of every activity and information of individual and organisation, characterised by numerous 'small brothers'. Transparency has become a key word in this ubiquitous era. Transparency in regulatory activities needs to be understood in following contexts. First, transparency is one of elements to build public confidence in regulator and eventually to achieve regulatory goal of providing the public with satisfaction at nuclear safety. Transparent bases of competence, independence, ethics and integrity of working process of regulatory body would enhance public confidence. Second, activities transmitting information on nuclear safety and preparedness to be accessed are different types of transparency. Communication is an active method of transparency. With increasing use of web-sites, 'digital transparency' is also discussed as passive one. Transparency in regulatory process may be more important than that of contents. Simply providing more information is of little value and specific information may need to be protected for security reason. Third, transparency should be discussed in international, national and organizational perspectives. It has been demanded through international instruments. for each country, transparency is demanded by residents, public, NGOs, media and other stakeholders. Employees also demand more transparency in operating and regulatory organisations. Whistle-blower may appear unless they are satisfied. Fourth, pursuing transparency may cause undue social cost or adverse effects. Over-transparency may decrease public confidence and the process for transparency may also hinder

  19. Prevalence of upper limb disorders among female librarians.

    Science.gov (United States)

    Pandy, R

    2013-09-01

    Work as a librarian involves exposure to potential risk factors for developing upper limb disorders. The prevalence of upper limb symptoms has, however, not previously been assessed in this occupational group. To estimate the 7-day and annual prevalence of self-reported neck and upper limb symptoms in librarians and to examine associations with specific tasks and ergonomic risk factors. A cross-sectional study using components of the standardized Nordic questionnaire. The study population consisted of librarians employed by a large local authority, and data collection was by means of a self-administered questionnaire. from studies on keyboard workers and on the general population were used as comparators. The 7-day prevalence of self-reported neck and upper limb pain in female librarians was 42% (95% confidence interval (CI) 33.7-50.5) and the annual prevalence was 65% (95% CI 56.6-72.8). The prevalence of reported wrist and hand pain increased with increased working involving a wide thumb-index span (P < 0.05) with a significant linear trend in prevalence with increasing exposure (P < 0.01). There was a strong association between reporting hand and/or wrist pain and awareness of work-related upper limb disorder (P < 0.05). The annual prevalence of self-reported upper limb symptoms among female librarians was high, but there was insufficient evidence to confirm whether the prevalence was higher than in the general population or among keyboard workers. Working with a wide thumb-index span was associated with reporting upper limb symptoms.

  20. Experimental uncertainty estimation and statistics for data having interval uncertainty.

    Energy Technology Data Exchange (ETDEWEB)

    Kreinovich, Vladik (Applied Biomathematics, Setauket, New York); Oberkampf, William Louis (Applied Biomathematics, Setauket, New York); Ginzburg, Lev (Applied Biomathematics, Setauket, New York); Ferson, Scott (Applied Biomathematics, Setauket, New York); Hajagos, Janos (Applied Biomathematics, Setauket, New York)

    2007-05-01

    This report addresses the characterization of measurements that include epistemic uncertainties in the form of intervals. It reviews the application of basic descriptive statistics to data sets which contain intervals rather than exclusively point estimates. It describes algorithms to compute various means, the median and other percentiles, variance, interquartile range, moments, confidence limits, and other important statistics and summarizes the computability of these statistics as a function of sample size and characteristics of the intervals in the data (degree of overlap, size and regularity of widths, etc.). It also reviews the prospects for analyzing such data sets with the methods of inferential statistics such as outlier detection and regressions. The report explores the tradeoff between measurement precision and sample size in statistical results that are sensitive to both. It also argues that an approach based on interval statistics could be a reasonable alternative to current standard methods for evaluating, expressing and propagating measurement uncertainties.

  1. The relationship between confidence in charitable organizations and volunteering revisited

    NARCIS (Netherlands)

    Bekkers, René H.F.P.; Bowman, Woods

    2009-01-01

    Confidence in charitable organizations (charitable confidence) would seem to be an important prerequisite for philanthropic behavior. Previous research relying on cross-sectional data has suggested that volunteering promotes charitable confidence and vice versa. This research note, using new

  2. Diagnosing Anomalous Network Performance with Confidence

    Energy Technology Data Exchange (ETDEWEB)

    Settlemyer, Bradley W [ORNL; Hodson, Stephen W [ORNL; Kuehn, Jeffery A [ORNL; Poole, Stephen W [ORNL

    2011-04-01

    Variability in network performance is a major obstacle in effectively analyzing the throughput of modern high performance computer systems. High performance interconnec- tion networks offer excellent best-case network latencies; how- ever, highly parallel applications running on parallel machines typically require consistently high levels of performance to adequately leverage the massive amounts of available computing power. Performance analysts have usually quantified network performance using traditional summary statistics that assume the observational data is sampled from a normal distribution. In our examinations of network performance, we have found this method of analysis often provides too little data to under- stand anomalous network performance. Our tool, Confidence, instead uses an empirically derived probability distribution to characterize network performance. In this paper we describe several instances where the Confidence toolkit allowed us to understand and diagnose network performance anomalies that we could not adequately explore with the simple summary statis- tics provided by traditional measurement tools. In particular, we examine a multi-modal performance scenario encountered with an Infiniband interconnection network and we explore the performance repeatability on the custom Cray SeaStar2 interconnection network after a set of software and driver updates.

  3. Towards Measurement of Confidence in Safety Cases

    Science.gov (United States)

    Denney, Ewen; Paim Ganesh J.; Habli, Ibrahim

    2011-01-01

    Arguments in safety cases are predominantly qualitative. This is partly attributed to the lack of sufficient design and operational data necessary to measure the achievement of high-dependability targets, particularly for safety-critical functions implemented in software. The subjective nature of many forms of evidence, such as expert judgment and process maturity, also contributes to the overwhelming dependence on qualitative arguments. However, where data for quantitative measurements is systematically collected, quantitative arguments provide far more benefits over qualitative arguments, in assessing confidence in the safety case. In this paper, we propose a basis for developing and evaluating integrated qualitative and quantitative safety arguments based on the Goal Structuring Notation (GSN) and Bayesian Networks (BN). The approach we propose identifies structures within GSN-based arguments where uncertainties can be quantified. BN are then used to provide a means to reason about confidence in a probabilistic way. We illustrate our approach using a fragment of a safety case for an unmanned aerial system and conclude with some preliminary observations

  4. Comparing interval estimates for small sample ordinal CFA models.

    Science.gov (United States)

    Natesan, Prathiba

    2015-01-01

    Robust maximum likelihood (RML) and asymptotically generalized least squares (AGLS) methods have been recommended for fitting ordinal structural equation models. Studies show that some of these methods underestimate standard errors. However, these studies have not investigated the coverage and bias of interval estimates. An estimate with a reasonable standard error could still be severely biased. This can only be known by systematically investigating the interval estimates. The present study compares Bayesian, RML, and AGLS interval estimates of factor correlations in ordinal confirmatory factor analysis models (CFA) for small sample data. Six sample sizes, 3 factor correlations, and 2 factor score distributions (multivariate normal and multivariate mildly skewed) were studied. Two Bayesian prior specifications, informative and relatively less informative were studied. Undercoverage of confidence intervals and underestimation of standard errors was common in non-Bayesian methods. Underestimated standard errors may lead to inflated Type-I error rates. Non-Bayesian intervals were more positive biased than negatively biased, that is, most intervals that did not contain the true value were greater than the true value. Some non-Bayesian methods had non-converging and inadmissible solutions for small samples and non-normal data. Bayesian empirical standard error estimates for informative and relatively less informative priors were closer to the average standard errors of the estimates. The coverage of Bayesian credibility intervals was closer to what was expected with overcoverage in a few cases. Although some Bayesian credibility intervals were wider, they reflected the nature of statistical uncertainty that comes with the data (e.g., small sample). Bayesian point estimates were also more accurate than non-Bayesian estimates. The results illustrate the importance of analyzing coverage and bias of interval estimates, and how ignoring interval estimates can be misleading

  5. Interval vs massed training: how best do we teach surgery?

    Science.gov (United States)

    Kesser, Bradley W; Hallman, Matthew; Murphy, Loren; Tillar, Maggie; Keeley, Meg; Peirce, Shayn

    2014-01-01

    To compare 2 different training paradigms, massed vs interval training, when novice students learn a surgical procedure, myringotomy with ventilation tube insertion, on a validated surgical simulator. Medical students were randomized into 2 training groups: the interval group (n = 19) was trained to perform the procedure in 5 trials/d over 3 days, and the massed group (n = 21) was trained to perform the procedure in 15 trials all in 1 session. One week later, all students were tested in 5 additional final trials. Pre- and posttest surveys were administered. Academic medical center. Forty medical students: 19 students in the interval group were compared with 21 students in the massed group. Time to complete the procedure and number and type of error made were recorded and compared between groups. Pre- and poststudy surveys examined confidence levels working under a microscope and with the procedure. Students in both groups had a significant decrease in time between practice and final trials. In the final 5 trials, there was no difference in average time to complete the procedure between the massed and interval training groups. No difference was observed in the number of errors committed per trial between initial and final trials (both groups) or between massed and interval training groups. The students' confidence levels significantly increased across the trials, regardless of group. Surgical training improves proficiency, but method of training had little impact on proficiency in performing a simulated surgical procedure in this setting.

  6. Prevalence of Hypertension in Member Countries of South Asian Association for Regional Cooperation (SAARC)

    DEFF Research Database (Denmark)

    Neupane, Dinesh; McLachlan, Craig S; Sharma, Rajan

    2014-01-01

    Hypertension is a leading attributable risk factor for mortality in South Asia. However, a systematic review on prevalence and risk factors for hypertension in the region of the South Asian Association for Regional Cooperation (SAARC) has not carried out before.The study was conducted according...... that the prevalence was higher among women than men. Meta-analyses showed that sex (men: odds ratio [OR] 1.19; 95% confidence interval [CI]: 1.02, 1.37), obesity (OR 2.33; 95% CI: 1.87, 2.78), and central obesity (OR 2.16; 95% CI: 1.37, 2.95) were associated with hypertension.Our study found a variable prevalence...

  7. Prevalence of amblyopia among secondary school students in Calabar, south-south Nigeria.

    Science.gov (United States)

    Megbelayin, E O

    2012-01-01

    To determine the prevalence of amblyopia among secondary school students in Calabar metropolis It was a cross-sectional study with subjects recruited by multi-stage simple random technique. A total of 1,241 students were eligible of which 1,175 were available for vision screening with Snellen's chart. Students whose visual acuities (VA) were 6/9 in either eye were considered emmetropic. History, ocular alignments, anterior and posterior segment examinations were carried out. Students with best-corrected VAamblyopia prevalence was 0.3% (95% confidence interval [CI], 0.27 - 0.35) with no sex (P-value = 0.088) effects but showed statistical significance with age (chi-square, chi2 = 140.954, P-value = 0.000) The prevalence of amblyopia in this study is relatively low compared to otherAfrican and non-African studies.

  8. Obesity and prevalence of risk behaviour for eating disorders among young Danish women

    DEFF Research Database (Denmark)

    Waaddegaard, Mette; Davidsen, Michael; Kjøller, Mette

    2009-01-01

    Health Interview Survey and an 8-item screen, RiBED-8, for risk behaviour for eating disorders. To analyze how the prevalence of risk behaviour depends on age, BMI, and year of survey, logistic regression analyses were applied. On acceptance of no interaction, the effect of each variable was tested......AIMS: Danish women aged 16-29 from two nationwide, representative, cross-sectional interview/questionnaire surveys from 2000 and 2005 are analyzed for trends in prevalence of risk behaviour for developing eating disorders and associations to BMI and age. METHODS: Participants completed the Danish...... and described using odds ratios with 95% confidence intervals. RESULTS: Women aged 16-19 or with a BMI of>25 had the greatest chance of reporting risk behaviour for eating disorders. However, many women in their 20s also had risk behaviour. Prevalence of risk behaviour for eating disorders did not change from...

  9. Prevalence of asthma and bronchial hyperreactivity in Danish schoolchildren: no change over 10 years

    DEFF Research Database (Denmark)

    Zilmer, Monica; Steen, Nick Phaff; Zachariassen, Gitte

    2011-01-01

    Aim:  To describe the point prevalence of current physician-diagnosed asthma and bronchial hyperreactivity (BHR) in 2001 among unselected Danish schoolchildren aged 6-17 years, compared with the prevalence from a similar study from 1990 to 1991. Methods:  Cross-sectional study using parental...... questionnaire on asthma and respiratory symptoms combined with a 6-min free running test with peak expiratory flow rate (PEFR) measurement (n = 1051, response rate 89.3%). Results were compared with those of a similar study in the same area from 1990 to 1991. Main outcome measures were current physician......-diagnosed asthma or BHR in children without physician-diagnosed asthma measured by either a decrease in lung function after standardized running test and/or variability in PEFR on home monitoring. Results:  The prevalence of current physician-diagnosed asthma was 4.0% [95% confidence interval (CI) 2...

  10. Incidence, Prevalence, Diagnostic Delay, and Clinical Presentation of Female 46,XY Disorders of Sex Development

    DEFF Research Database (Denmark)

    Berglund, Agnethe; Johannsen, Trine H; Stochholm, Kirstine

    2016-01-01

    , prevalence, age at diagnosis, and clinical presentation at diagnosis in 46,XY females. DESIGN AND SETTING: A nationwide study covering all known females with a 46,XY karyotype in Denmark since 1960. The diagnosis of 46,XY disorder of sex development (DSD) was determined by medical record evaluation, data......CONTEXT: The prevalence of phenotypic females with a 46,XY karyotype is low, thus current knowledge about age and clinical presentation at diagnosis is sparse even for the most frequent conditions, androgen insensitivity syndrome (AIS), and gonadal dysgenesis. OBJECTIVE: To estimate incidence.......0-13.5; range, 0-34 y) in AIS and 17.0 years (95% confidence interval, 15.5-19.0; range, 0-28 y) in gonadal dysgenesis (P = .001). Clinical presentation was dependent on cause of DSD. CONCLUSIONS: The first estimate on prevalence of 46,XY females is 6.4 per 100 000 live born females. The presentation of AIS...

  11. Q fever: prevalence of antibodies to Coxiella burnetii in the Basque country.

    Science.gov (United States)

    Sanzo, J M; Garcia-Calabuig, M A; Audicana, A; Dehesa, V

    1993-12-01

    The aim of this study was to ascertain the prevalence of Coxiella burnetii infection in the Basque population. To this end a stratified sampling was carried out taking as a criterion the size of the population in a given area of residence. Residents in sparsely populated areas were found to have a prevalence of 38.5%, significantly greater than in highly populated areas (odds ratio [OR] = 1.56; 95% confidence interval [CI]: 1.08-2.27 and OR = 1.58; 95% CI: 1.09-2.30). The prevalence was significantly higher in males (36.3%) than in females (29%), and was found to increase significantly with age. Current or previous participation in activities relating to agriculture and/or livestock farming or even having contact with cattle, goats or sheep were also found to be risk factors for the infection. A fuller study of the determinants of chronic Q fever should be initiated.

  12. Confidence crisis of results in biomechanics research.

    Science.gov (United States)

    Knudson, Duane

    2017-11-01

    Many biomechanics studies have small sample sizes and incorrect statistical analyses, so reporting of inaccurate inferences and inflated magnitude of effects are common in the field. This review examines these issues in biomechanics research and summarises potential solutions from research in other fields to increase the confidence in the experimental effects reported in biomechanics. Authors, reviewers and editors of biomechanics research reports are encouraged to improve sample sizes and the resulting statistical power, improve reporting transparency, improve the rigour of statistical analyses used, and increase the acceptance of replication studies to improve the validity of inferences from data in biomechanics research. The application of sports biomechanics research results would also improve if a larger percentage of unbiased effects and their uncertainty were reported in the literature.

  13. Considering public confidence in developing regulatory programs

    International Nuclear Information System (INIS)

    Collins, S.J.

    2001-01-01

    In the area of public trust and in any investment, planning and strategy are important. While it is accepted in the United States that an essential part of our mission is to leverage our resources to improving Public Confidence this performance goal must be planned for, managed and measured. Similar to our premier performance goal of Maintaining Safety, a strategy must be developed and integrated with our external stake holders but with internal regulatory staff as well. In order to do that, business is to be conducted in an open environment, the basis for regulatory decisions has to be available through public documents and public meetings, communication must be done in clear and consistent terms. (N.C.)

  14. Beyond social support: Self-care confidence is key for adherence in patients with heart failure.

    Science.gov (United States)

    Hammash, Muna H; Crawford, Timothy; Shawler, Celeste; Schrader, Melanie; Lin, Chin-Yen; Shewekah, Deena; Moser, Debra K

    2017-10-01

    Adherence to treatment is crucial to improve outcomes in patients with heart failure. Good social support is associated with better adherence, but the mechanism for this association has not been well-explored. The aim of this secondary analysis was to examine whether self-care confidence mediates the relationship between social support and treatment adherence in heart failure patients hospitalized with acute exacerbation. A total of 157 inpatients with heart failure (63.5±13 years, 73% New York Heart Association class III/IV) were recruited from two hospitals located in urban areas in the USA. Participants completed the Self-Care of Heart Failure Index, the Multidimensional Perceived Social Support Scale, and the Medical Outcomes Study Specific Adherence Scale. A series of regression models were used to determine the mediation relationship. Controlling for marital status and hospital site, social support was associated with adherence ( p=0.03). When self-confidence was included in the model, the effect of social support became non-significant, indicating full mediation of the relationship between social support and adherence by self-care confidence. The indirect effect (0.04) of social support on adherence through self-confidence was significant (95% confidence interval: 0.01-0.09). Heart failure self-care confidence mediated the relationship between social support and treatment adherence. Thus interventions targeting patients' self-care confidence is essential to maximize patients' treatment adherence.

  15. Measurement of confidence: the development and psychometric evaluation of a stroke-specific, measure of confidence.

    Science.gov (United States)

    Horne, Jane C; Lincoln, Nadina B; Logan, Pip A

    2017-11-01

    To design, develop and psychometrically evaluate a stroke-specific measure of confidence, the Confidence after Stroke Measure (CaSM). Cross-sectional. Adults in the community. Stroke survivors and healthy elderly participants. Questionnaire items were generated based on the literature and qualitative interviews and piloted with expert groups to establish face validity. A 53-item CaSM was administered to stroke survivors and healthy elderly participants in the community. A second copy was posted four weeks later. Completed questionnaires were analysed for extreme responses, missing values, construct validity (factor analysis), convergent validity, divergent validity, reliability (internal consistency and temporal stability) and comparing responses according to age and gender. Stroke ( n = 101) and healthy elderly participants ( n = 101) returned questionnaires. Eight items were removed that had extreme responses and large numbers of missing values. Six items had item total correlations Confidence, Positive Attitude and Social Confidence, which explained 52% of variance. Cronbach's alpha coefficient demonstrated good internal consistency ( α = 0.94). A test re-test on the 27 items indicated good temporal stability ( r = 0.85, P = 0.001). The 27-item CaSM was a valid and reliable measure for assessing confidence in stroke survivors.

  16. Cannabis use in first episode psychosis: Meta-analysis of prevalence, and the time course of initiation and continued use.

    Science.gov (United States)

    Myles, Hannah; Myles, Nicholas; Large, Matthew

    2016-03-01

    Cannabis use is prevalent among people with first episode psychosis and the epidemiology of its use in early psychosis is unclear. We performed a meta-analysis of observational studies to determine; (1) the interval between age at initiation of cannabis use and age at onset of first episode psychosis, (2) the prevalence of cannabis use at time of first episode psychosis, and (3) the odds of continuing cannabis following treatment for first episode psychosis. Search of electronic databases MEDLINE, EMBASE, PsycINFO, Web of Science and CINAHL for English-language papers using search terms (psychosis OR schizophrenia) AND (cannabis OR marijuana) IN (title OR keyword OR abstract), current to October 2014. Studies were included if they reported on prevalence of current cannabis use in first episode psychosis cohorts. A total of 37 samples were included for meta-analysis. Rates of cannabis use in each sample were extracted to determine prevalence estimates. The age at initiation of regular cannabis and age at onset of psychosis were used to determine the length of cannabis use preceding psychosis. Prevalence estimates at first episode psychosis and various time points of follow-up following first episode psychosis were analysed to determine odds ratio of continuing cannabis use. Data synthesis was performed using random-effects meta-analyses. The pooled estimate for the interval between initiation of regular cannabis use and age at onset of psychosis was 6.3 years (10 samples, standardised mean difference = 1.56, 95% confidence interval = [1.40, 1.72]). The estimated prevalence of cannabis use at first episode psychosis was 33.7% (35 samples, 95% confidence interval = [31%, 39%]). Odds of continued cannabis use between 6 months and 10 years following first episode psychosis was 0.56 (19 samples, 95% confidence interval = [0.40, 0.79]). © The Royal Australian and New Zealand College of Psychiatrists 2015.

  17. Inverse Interval Matrix: A Survey

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Farhadsefat, R.

    2011-01-01

    Roč. 22, - (2011), s. 704-719 E-ISSN 1081-3810 R&D Projects: GA ČR GA201/09/1957; GA ČR GC201/08/J020 Institutional research plan: CEZ:AV0Z10300504 Keywords : interval matrix * inverse interval matrix * NP-hardness * enclosure * unit midpoint * inverse sign stability * nonnegative invertibility * absolute value equation * algorithm Subject RIV: BA - General Mathematics Impact factor: 0.808, year: 2010 http://www.math.technion.ac.il/iic/ela/ela-articles/articles/vol22_pp704-719.pdf

  18. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13...

  19. The 2010 Retirement Confidence Survey: confidence stabilizing, but preparations continue to erode.

    Science.gov (United States)

    Helman, Ruth; Copeland, Craig; VanDerhei, Jack

    2010-03-01

    20TH ANNUAL RCS: The 2010 Retirement Confidence Survey-the 20th annual wave of this survey-finds that the record-low confidence levels measured during the past two years of economic decline appear to have bottomed out. The percentage of workers veryconfident about having enough money for a comfortable retirement has stabilized at 16 percent, which is statistically equivalent to the 20-year low of 13 percent measured in 2009 (Fig. 1, pg. 7). Retiree confidence about having a financially secure retirement has also stabilized, with 19 percent saying now they are very confident (statistically equivalent to the 20 percent measured in 2009) (Fig. 2, pg. 8). Worker confidence about paying for basic expenses in retirement has rebounded slightly, with 29 percent now saying they are very confident about having enough money to pay for basic expenses during retirement (up from 25 percent in 2009, but still down from 34 percent in 2008) (Fig. 3, pg. 9). PREPARATIONS STILL ERODING: Fewer workers report that they and/or their spouse have saved for retirement (69 percent, down from 75 percent in 2009 but statistically equivalent to 72 percent in 2008) (Fig. 11, page 14). Moreover, fewer workers say that they and/or their spouse are currently saving for retirement (60 percent, down from 65 percent in 2009 but statistically equivalent to percentages measured in other years) (Fig. 13, pg. 15). MORE PEOPLE HAVE NO SAVINGS AT ALL: An increased percentage of workers report they have virtually no savings and investments. Among RCS workers providing this type of information, 27 percent say they have less than $1,000 in savings (up from 20 percent in 2009). In total, more than half of workers (54 percent) report that the total value of their household's savings and investments, excluding the value of their primary home and any defined benefit plans, is less than $25,000 (Fig. 14, pg. 16). CLUELESS ABOUT SAVINGS GOALS: Many workers continue to be unaware of how much they need to save for

  20. Confidence as motivational expressions of interest, utility, and other influences: Exploring under-confidence and over-confidence in science students at secondary school

    OpenAIRE

    Sheldrake, Richard

    2016-01-01

    An enhanced understanding of how students’ self-confidence is influenced benefits educational practice and motivational theories. For 1523 students in 12 secondary schools in England, science self-confidence was predicted by various factors: current self-confidence (self-concept) was most strongly predicted by received praise, current grades, and interest in science; self-confidence for future attainment (self-efficacy) was most strongly predicted by current grades and perceived utility of sc...

  1. Smokeless tobacco consumption in the South Asian population of Sydney, Australia: prevalence, correlates and availability.

    Science.gov (United States)

    Hossain, Mohammad Shakhawat; Kypri, Kypros; Rahman, Bayzidur; Milton, Abul Hasnat

    2014-01-01

    AIM.: The aim of this study was to estimate the prevalence and identify correlates of smokeless tobacco consumption among the South Asian residents of Sydney, Australia. A cross-sectional survey was conducted using a pretested, self-administered mailed questionnaire among members of Indian, Pakistani and Bangladeshi community associations in Sydney. Of 1600 individuals invited to participate, 419 responded (26%). Prevalence rates of ever consumption, more than 100 times consumption and current consumption were 72.1%, 65.9% and 17.1%, respectively. Men (74.3%) were more likely to ever consume than women (67.6%). Over 96% of consumers reported buying smokeless tobacco products from ethnic shops in Sydney. Current consumption of smokeless tobacco products was associated with country of birth: Indians (odds ratio 5.7, 95% confidence interval 2.3-14.5) and Pakistanis (odds ratio 3.1, 95% confidence interval 1.5-6.5) were more likely to be current consumers than Bangladeshis after adjusting for sociodemographic variables. For ever consumption, there was a positive association with age (P for trend=0.013) and male gender (odds ratio 2.1, 95% confidence interval 1.5-3.1). Given the availability of smokeless tobacco and the high prevalence and potential adverse health consequences of consumption, smokeless tobacco consumption may produce a considerable burden of non-communicable disease in Australia. Effective control measures are needed, in particular enforcement of existing laws prohibiting the sale of these products. © 2013 Australasian Professional Society on Alcohol and other Drugs.

  2. Prevalence and determinants of chronic obstructive pulmonary disease among a sample of adult smokers in Baghdad, Iraq, 2014.

    Science.gov (United States)

    Al Lami, Faris; Salim, Zainab

    2017-03-30

    This cross-sectional study was conducted to estimate the prevalence and identify determinants of chronic obstructive pulmonary disease (COPD) among a convenience sample of 325 adult smokers in Baghdad, Iraq, 2014. Beside demographic variables, participants had Lung Function Questionnaire to assess respiratory symptoms; individuals with a score of ≤18 had a spirometry examination. Those with FEV1/FVC ratio spirometry; those with FEV1/FVC% of 55 (OR=2.14, 95% confidence interval = 1.04-4.39), and pack year smoking >40 (OR =5.37, 95% confidence interval = 1.70-16.91) were the significant independent determinants. All adult smokers should have a spirometry testing and counseled to stop smoking.

  3. Prevalence of genital human papilloma virus infection and genotypes among young women in Sicily, South Italy.

    Science.gov (United States)

    Ammatuna, Pietro; Giovannelli, Lucia; Matranga, Domenica; Ciriminna, Saverio; Perino, Antonio

    2008-08-01

    Infection with oncogenic human papilloma virus (HPV) types is a necessary cause of cervical cancer. This study assessed the prevalence of HPV infection and genotypes among 1,006 randomly selected women, ages 18 to 24 years, living in Sicily (south Italy). The overall HPV rate was 24.1% (95% confidence interval, 21.5-26.9). The most frequent types were HPV-16 (4.5%), HPV-53 (2.7%), and HPV-84 (2.6%). The prevalence of vaccine types HPV-6, HPV-11, and HPV-18 was 1.4%, 0.1%, and 1.3%, respectively. Cytologic abnormalities were uncommon (3.1%) and associated with HPV detection (P < 0.0001). The only risk factor for HPV infection was the number of sexual partners (women with 2-3 partners versus women with 1 partner: odds ratio, 3.86; 95% confidence interval, 2.45-6.09). Genital HPV infection is relatively high in young Italian women. The high prevalence of viral types other than vaccine types should be taken into account to ensure accurate postvaccine surveillance and early detection of a possible genotype replacement.

  4. Relationships between dietary habits and the prevalence of fatigue in medical students.

    Science.gov (United States)

    Tanaka, Masaaki; Mizuno, Kei; Fukuda, Sanae; Shigihara, Yoshihito; Watanabe, Yasuyoshi

    2008-10-01

    Fatigue, which is a common complaint among medical students, is related to poor academic outcomes. Because impaired dietary habits, such as skipping breakfast and taking meals irregularly, are correlated with poor school performances, whether those dietary habits were associated with the prevalence of fatigue was determined in medical students. The study group consisted of 127 healthy second-year medical students attending Osaka City University Graduate School of Medicine. They completed a questionnaire dealing with fatigue (Japanese version of the Chalder Fatigue Scale), lifestyle, and academic performance. On multivariate logistic regression analyses adjusted for age, gender, body mass index, and nocturnal sleeping hours, skipping breakfast (completely skipping breakfast everyday versus having breakfast everyday; odds ratio 7.81, 95% confidence interval 2.00-30.52, P = 0.003) and taking meals irregularly (completely irregular versus always regular; odds ratio 6.89, 95% confidence interval 1.20-39.55, P = 0.030) were positively correlated with the prevalence of fatigue. Skipping breakfast and taking meals irregularly are associated with the prevalence of fatigue in medical students.

  5. ERICA: smoking prevalence in Brazilian adolescents

    Directory of Open Access Journals (Sweden)

    Valeska Carvalho Figueiredo

    2016-02-01

    Full Text Available ABSTRACT OBJECTIVE To estimate the prevalences of tobacco use, tobacco experimentation, and frequent smoking among Brazilian adolescents. METHODS We evaluated participants of the cross-sectional, nation-wide, school-based Study of Cardiovascular Risks in Adolescents (ERICA, which included 12- to 17-year-old adolescents from municipalities of over 100 thousand inhabitants. The study sample had a clustered, stratified design and was representative of the whole country, its geographical regions, and all 27 state capitals. The information was obtained with self-administered questionnaires. Tobacco experimentation was defined as having tried cigarettes at least once in life. Adolescents who had smoked on at least one day over the previous 30 days were considered current cigarette smokers. Having smoked cigarettes for at least seven consecutive days was an indicator for regular consumption of tobacco. Considering the complex sampling design, prevalences and 95% confidence intervals were estimated according to sociodemographic and socio-environmental characteristics. RESULTS We evaluated 74,589 adolescents. Among these, 18.5% (95%CI 17.7-19.4 had smoked at least once in life, 5.7% (95%CI 5.3-6.2 smoked at the time of the research, and 2.5% (95%CI 2.2-2.8 smoked often. Adolescents aged 15 to 17 years had higher prevalences for all indicators than those aged 12 to 14 years. The prevalences did not differ significantly between sexes. The highest prevalences were found in the South region and the lowest ones, in the Northeast region. Regardless of sex, the prevalences were found to be higher for adolescents who had had paid jobs, who lived with only one parent, and who reported having been in contact with smokers either inside or outside their homes. Female public school adolescents were found to smoke more than the ones from private schools. CONCLUSIONS Tobacco use among adolescents is still a challenge. Intending to reduce the prevalence of tobacco use

  6. ERICA: smoking prevalence in Brazilian adolescents

    Science.gov (United States)

    Figueiredo, Valeska Carvalho; Szklo, André Salem; Costa, Letícia Casado; Kuschnir, Maria Cristina C; da Silva, Thiago Luiz Nogueira; Bloch, Katia Vergetti; Szklo, Moyses

    2016-01-01

    ABSTRACT OBJECTIVE To estimate the prevalences of tobacco use, tobacco experimentation, and frequent smoking among Brazilian adolescents. METHODS We evaluated participants of the cross-sectional, nation-wide, school-based Study of Cardiovascular Risks in Adolescents (ERICA), which included 12- to 17-year-old adolescents from municipalities of over 100 thousand inhabitants. The study sample had a clustered, stratified design and was representative of the whole country, its geographical regions, and all 27 state capitals. The information was obtained with self-administered questionnaires. Tobacco experimentation was defined as having tried cigarettes at least once in life. Adolescents who had smoked on at least one day over the previous 30 days were considered current cigarette smokers. Having smoked cigarettes for at least seven consecutive days was an indicator for regular consumption of tobacco. Considering the complex sampling design, prevalences and 95% confidence intervals were estimated according to sociodemographic and socio-environmental characteristics. RESULTS We evaluated 74,589 adolescents. Among these, 18.5% (95%CI 17.7-19.4) had smoked at least once in life, 5.7% (95%CI 5.3-6.2) smoked at the time of the research, and 2.5% (95%CI 2.2-2.8) smoked often. Adolescents aged 15 to 17 years had higher prevalences for all indicators than those aged 12 to 14 years. The prevalences did not differ significantly between sexes. The highest prevalences were found in the South region and the lowest ones, in the Northeast region. Regardless of sex, the prevalences were found to be higher for adolescents who had had paid jobs, who lived with only one parent, and who reported having been in contact with smokers either inside or outside their homes. Female public school adolescents were found to smoke more than the ones from private schools. CONCLUSIONS Tobacco use among adolescents is still a challenge. Intending to reduce the prevalence of tobacco use among young

  7. Smoking prevalence among monks in Thailand.

    Science.gov (United States)

    Kungskulniti, Nipapun; Charoenca, Naowarut; Kengganpanich, Tharadol; Kusolwisitkul, Wilai; Pichainarong, Natchaporn; Kerdmongkol, Patcharaporn; Silapasuwan, Phimpan; Hamann, Stephen L; Arpawong, Thalida Em

    2012-09-01

    Previous studies among Buddhist monks in Thailand have reported smoking rates to be as high as 55%. Because 95% of Thais are Buddhist, monks are highly influential in establishing normative behavioral patterns. As the first population-based study on smoking among Buddhist monks in Thailand, this study aims to determine the smoking prevalence in six regions of the country, and to examine smoking knowledge, risk perceptions, behaviors, and associated demographics among full-fledged and novice monks (n = 6,213). Results demonstrated that the overall prevalence for current smoking monks is 24.4% (95% confidence interval [24.453, 24.464]), with regional differences ranging from 14.6% (North) to 40.5% (East). Findings suggest that integrating prevention and cessation programming into religious courses may be one avenue for reaching many incoming monks. Further, involving monks in tobacco control education and setting a nonsmoking standard among them is vital to the success of reducing smoking rates among the general population in Thailand.

  8. Meta-analysis to refine map position and reduce confidence intervals for delayed canopy wilting QTLs in soybean

    Science.gov (United States)

    Slow canopy wilting in soybean has been identified as a potentially beneficial trait for ameliorating drought effects on yield. Previous research identified QTLs for slow wilting from two different bi-parental populations and this information was combined with data from three other populations to id...

  9. A numerical approach to 14C wiggle-match dating of organic deposits: best fits and confidence intervals

    NARCIS (Netherlands)

    Blaauw, M.; Heuvelink, G.B.M.; Mauquoy, D.; Plicht, van der J.; Geel, van B.

    2003-01-01

    C-14 wiggle-match dating (WMD) of peat deposits uses the non-linear relationship between C-14 age and calendar age to match the shape of a sequence of closely spaced peat C-14 dates with the C-14 calibration curve. A numerical approach to WMD enables the quantitative assessment of various possible

  10. Confidence intervals for ARMA-GARCH Value-at-Risk : The case of heavy tails and skewness

    NARCIS (Netherlands)

    Spierdijk, Laura

    It is a well-known result that, when the ARMA GARCH model errors lack a finite fourth moment, the asymptotic distribution of the quasi-maximum likelihood estimator may not be Normal. In such a scenario the conventional bootstrap turns out inconsistent. Surprisingly, simulations show that the

  11. Derivation of confidence intervals of service measures in a base-stock inventory control system with low-frequent demand

    DEFF Research Database (Denmark)

    Larsen, Christian

    We explore a base-stock system with backlogging where the demand process is a compound renewal process and the compound element is a delayed geometric distribution. For this setting it is proven in [4] that the long-run average service measures order fill rate (OFR) and volume fill rate (VFR...... and VFR are estimated in a simulation using the regenerative method. Through numerical examples we show that of the two service measures it is OFR that can be estimated most accurately. However, simulation results show that the opposite conclusion holds if we instead consider finitehorizon service...

  12. Derivation of confidence intervals of service measures in a base-stock inventory control system with low-frequent demand

    DEFF Research Database (Denmark)

    Larsen, Christian

    2011-01-01

    We explore a base-stock system with backlogging where the demand process is a compound renewal process and the compound element is a delayed geometric distribution. For this setting it holds that the long-run average service measures order fill rate (OFR) and volume fill rate (VFR) are equal...... the regenerative method. Through numerical examples we show that of the two service measures it is OFR that in general can be estimated most accurately. However, simulation results show that the opposite conclusion holds if we instead consider finite-horizon service measures, namely per-cycle variants of OFR...

  13. Citation bias in reported smoking prevalence in people with schizophrenia.

    Science.gov (United States)

    Chapman, Simon; Ragg, Mark; McGeechan, Kevin

    2009-03-01

    A meta-analysis of 42 studies on tobacco smoking among schizophrenia subjects found an average smoking prevalence of 62% (range=14-88%). Statements are common, however, in the research literature and the media that between 80% and 90% of people with schizophrenia smoke. The purpose of the present paper was therefore to determine if citation bias exists in the over-citation and reportage of studies finding high rates of smoking prevalence in schizophrenia subjects. Two hypotheses were tested: (i) that studies on the prevalence of smoking in people with schizophrenia reporting high smoking rates would be cited more often than studies reporting lower rates; and (ii) that statements about smoking rates among schizophrenic people on the Internet would report very high rates more often than more realistic, less dramatic rates. A 10% increase in reported prevalence of smoking was associated with a 61% (95% confidence interval (CI)=30-98%) increase in citation rate. Journal impact factor (IF) was significantly associated with citation rate (p=0.001) but the country in which a study was carried out did not have an effect (p=0.90). After adjusting for IF, a 10% increase in prevalence of smoking was associated with a 28% increase (95%CI=1-62%) in citation rate. This bias is mirrored on the Internet, where statements abound about uncommonly highly rates of smoking by people with schizophrenia. Studies reporting very high prevalence of smoking among people with schizophrenia are cited more often than those studies reporting a low prevalence, a result consistent with citation bias. This citation bias probably contributes to the misinformation available on the Internet, and may have adverse policy and clinical implications.

  14. Does Consumer Confidence Forecast Household Spending? The Euro Area Case

    OpenAIRE

    Dion, David Pascal

    2006-01-01

    The following analysis, based on error correction models, suggests that consumer confidence, together with traditional macroeconomic variables, contains a forecasting and explicative power on consumption. By including consumer confidence in a consumption function, consumer confidence releases a significant coefficient. Such a confidence-augmented consumption model provides good forecasting results.

  15. Engineering Student Self-Assessment through Confidence-Based Scoring

    Science.gov (United States)

    Yuen-Reed, Gigi; Reed, Kyle B.

    2015-01-01

    A vital aspect of an answer is the confidence that goes along with it. Misstating the level of confidence one has in the answer can have devastating outcomes. However, confidence assessment is rarely emphasized during typical engineering education. The confidence-based scoring method described in this study encourages students to both think about…

  16. The 2009 Retirement Confidence Survey: economy drives confidence to record lows; many looking to work longer.

    Science.gov (United States)

    Helman, Ruth; Copeland, Craig; VanDerhei, Jack

    2009-04-01

    RECORD LOW CONFIDENCE LEVELS: Workers who say they are very confident about having enough money for a comfortable retirement this year hit the lowest level in 2009 (13 percent) since the Retirement Confidence Survey started asking the question in 1993, continuing a two-year decline. Retirees also posted a new low in confidence about having a financially secure retirement, with only 20 percent now saying they are very confident (down from 41 percent in 2007). THE ECONOMY, INFLATION, COST OF LIVING ARE THE BIG CONCERNS: Not surprisingly, workers overall who have lost confidence over the past year about affording a comfortable retirement most often cite the recent economic uncertainty, inflation, and the cost of living as primary factors. In addition, certain negative experiences, such as job loss or a pay cut, loss of retirement savings, or an increase in debt, almost always contribute to loss of confidence among those who experience them. RETIREMENT EXPECTATIONS DELAYED: Workers apparently expect to work longer because of the economic downturn: 28 percent of workers in the 2009 RCS say the age at which they expect to retire has changed in the past year. Of those, the vast majority (89 percent) say that they have postponed retirement with the intention of increasing their financial security. Nevertheless, the median (mid-point) worker expects to retire at age 65, with 21 percent planning to push on into their 70s. The median retiree actually retired at age 62, and 47 percent of retirees say they retired sooner than planned. WORKING IN RETIREMENT: More workers are also planning to supplement their income in retirement by working for pay. The percentage of workers planning to work after they retire has increased to 72 percent in 2009 (up from 66 percent in 2007). This compares with 34 percent of retirees who report they actually worked for pay at some time during their retirement. GREATER WORRY ABOUT BASIC AND HEALTH EXPENSES: Workers who say they very confident in

  17. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A N; Sosnovtseva, Olga; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov expone...

  18. Interval matrices: Regularity generates singularity

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Shary, S.P.

    2018-01-01

    Roč. 540, 1 March (2018), s. 149-159 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : interval matrix * regularity * singularity * P-matrix * absolute value equation * diagonally singilarizable matrix Subject RIV: BA - General Mathematics Impact factor: 0.973, year: 2016

  19. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific refe......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13......-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S...

  20. Dynamic Properties of QT Intervals

    Czech Academy of Sciences Publication Activity Database

    Halámek, Josef; Jurák, Pavel; Vondra, Vlastimil; Lipoldová, J.; Leinveber, Pavel; Plachý, M.; Fráňa, P.; Kára, T.

    2009-01-01

    Roč. 36, - (2009), s. 517-520 ISSN 0276-6574 R&D Projects: GA ČR GA102/08/1129; GA MŠk ME09050 Institutional research plan: CEZ:AV0Z20650511 Keywords : QT Intervals * arrhythmia diagnosis Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering http://cinc.mit.edu/archives/2009/pdf/0517.pdf

  1. [Prevalence of metabolic syndrome in Mapuche individuals living in urban and rural environment in Chile].

    Science.gov (United States)

    Ibáñez, Luis; Sanzana, Ruth; Salas, Carlos; Navarrete, Claudia; Cartes-Velásquez, Ricardo; Rainqueo, Angélica; Jara, Tamara; Pérez-Bravo, Francisco; Ulloa, Natalia; Calvo, Carlos; Miquel, Juan F; Celis-Morales, Carlos

    2014-08-01

    Metabolic Syndrome (MS) increases the risk of diabetes and mortality associated with cardiovascular disease. However, the prevalence of MS could differ by ethnicity and lifestyle factors. To determine the prevalence of MS in Mapuche individuals living in urban and rural environments in Chile and to investigate whether the prevalence and risk of MS in urban and rural environments differs by sex, age and nutritional status. A total of 1077 Mapuche participants were recruited from urban (MU = 288) and rural (MR = 789) settings. Body mass index, waist circumference and blood pressure were measured. A fasting blood sample was obtained to measure serum glucose, HDL cholesterol and triacylglycerol. The prevalence of MS was determined using the unified IDF and ATP-III criteria. An environment and sex interaction was found for the prevalence of MS (p = 0.042). The prevalence was significantly lower in male MR (13%) compared to other groups (22, 23 and 25% among female MR, female MU and male MU respectively). Also, the prevalence of central obesity and low HDL-cholesterol were significantly lower in male MR. MU are at an increased risk of developing MS compared to MR, with an odds ratio of 1.59 (95% confidence intervals 1.1 to 2.2). This risk increases along with age or body mass index of the population. The adoption of an urbanized lifestyle increases the risk of developing MS in Mapuche individuals. This risk is enhanced by age and nutritional status.

  2. Prevalence and change of central obesity among US Asian adults: NHANES 2011-2014.

    Science.gov (United States)

    Liu, Xuefeng; Chen, Yang; Boucher, Nicole L; Rothberg, Amy E

    2017-08-25

    Central obesity is a major risk factor for cardiometabolic diseases. The prevalence of central obesity has not been reported fully among Asian adults in the United States (US). Cross-sectional data of 1288 Asian adults aged 20 years or over was selected from the US National Health and Nutrition Examination Survey with a stratified multi-stage sampling design. The prevalence of central obesity was calculated with 95% confidence intervals (CIs) and Chi-square tests were conducted to test the significance of the prevalence differences across characteristic groups. The overall prevalence of central obesity among US Asian adults was 58.1% in 2011-2014. The prevalence of central obesity was higher in older adults (73.5%) than in young adults (45.4%) (p young adults (39.2% vs 51.5%), men (45.4% vs 56.6%), adults with college education or above (54.2% vs 61.7%) and non-poor adults (55.4% vs 62.4%). Compared with men, women had higher prevalence in each subgroup of age, education, poverty, and length of time (except for the subgroup of "born in the US") (all p obesity is prevalent in Asian adults, particularly in older adults and women. More efforts are needed to prevent and treat obesity in Asian adults as Asians are incurring the greatest increase in type 2 diabetes in parallel with the rising rate of central adiposity.

  3. Prevalence of diabetic retinopathy in Iran: a systematic review and Meta-analysis

    Directory of Open Access Journals (Sweden)

    Saman Maroufizadeh

    2017-05-01

    Full Text Available AIM: To estimate the overall prevalence of diabetic retinopathy (DR in Iran by a systematic review and Meta-analysis. METHODS: We conducted a search of all published literature on diabetic patients for the prevalence of DR using Web of Sciences, PubMed, Scopus, Google Scholar, and national electronic databases SID, Magiran, and Iranmedex from their inception until September 2016 with standard keywords. Pooled estimates of the DR prevalence and the corresponding 95% confidence intervals (CI were calculated using random effects models. RESULTS: Thirty-one studies involving 23 729 patients with type I and II diabetes were included. The publication bias assumption for prevalence of DR was rejected by Begg and Egger tests (P=0.825, P=0.057, respectively. The results of Cochran test and I2 statistics showed considerable heterogeneity for prevalence of DR (Q=1278.21, d.f.=30, P<0.001 and I2=97.7%. The prevalence of DR, non-proliferative diabetic retinopathy (NPDR and proliferative diabetic retinopathy (PDR in Iranian diabetic patients were 41.9% (95% CI: 35.6-48.2, 32.2% (95% CI: 28.7-35.8, and 13.2% (95% CI: 8.3-18.1, respectively. CONCLUSION: The prevalence of DR in Iran appears a little high. NPDR was more common. This study highlights the necessity for DR screening and management in diabetic patients in Iran.

  4. Prevalence of Sarcoptes scabiei infection in pet dogs in southern China.

    Science.gov (United States)

    Chen, Yi-Zhou; Liu, Guo-Hua; Song, Hui-Qun; Lin, Rui-Qing; Weng, Ya-Biao; Zhu, Xing-Quan

    2014-01-01

    Little is known about the prevalence of Sarcoptes scabiei infection in pet dogs in China. In the present study, the prevalence of S. scabiei infection in pet dogs in Guangzhou, southern China, was investigated between January and December, 2009. A total of 3,977 pet dogs admitted to animal hospitals were examined for the presence of S. scabiei using a parasitological approach. The average prevalence of S. scabiei infection in pet dogs is 1.18% (95% confidence interval (CI): 0.85-1.52%). The prevalence of S. scabiei was higher in winter (1.42%; 95% CI: 0.29-2.55%), summer (1.39%; 95% CI: 0.83-1.96%), and autumn (1.1%; 95% CI: 0.53-1.68%) than in spring (0.63%; 95% CI: 0.02-1.25%). Furthermore, the prevalence of S. scabiei was the highest in Pekingese (21.88%; 95% CI: 7.55-36.2%), followed by Papillon (5.26%; 95% CI: 0-11.06%) and Bichon Frise (3.19%; 95% CI: 0-6.75%). The results of the present investigation indicate that S. scabiei infection is prevalent in pet dogs in Guangzhou, China, which provides relevant "baseline" data for conducting control strategies and measures against scabies in this region and elsewhere in China. To our knowledge, this is the first comprehensive report of S. scabiei prevalence in pet dogs in China.

  5. Explicit representation of confidence informs future value-based decisions

    DEFF Research Database (Denmark)

    Folke, Tomas; Jacobsen, Catrine; Fleming, Stephen M.

    2016-01-01

    Humans can reflect on decisions and report variable levels of confidence. But why maintain an explicit representation of confidence for choices that have already been made and therefore cannot be undone? Here we show that an explicit representation of confidence is harnessed for subsequent changes...... of mind. Specifically, when confidence is low, participants are more likely to change their minds when the same choice is presented again, an effect that is most pronounced in participants with greater fidelity in their confidence reports. Furthermore, we show that choices reported with high confidence...... of confidence has a positive impact on the quality of future value-based decisions....

  6. Prevalence and Social Risk Factors for Hearing Impairment in Chinese Children—A National Survey

    OpenAIRE

    Chunfeng Yun; Zhenjie Wang; Jiamin Gao; Ping He; Chao Guo; Gong Chen; Xiaoying Zheng

    2017-01-01

    Hearing impairment may affect children’s communication skills, social development, and educational achievement. Little is known about the prevalence of hearing impairment among Chinese children. Data were taken from the 2006 second China National Survey on Disability (CNSD). Hearing impairment was defined as moderate (41–60 dB HL), severe (61–80 dB HL), profound (81–90 dB HL), or complete (>91 dB HL). Logistic regression was used to estimate the odds ratio (OR) and 95% confidence intervals...

  7. Effect of gender on hospital admissions for asthma and prevalence of self-reported asthma

    DEFF Research Database (Denmark)

    Prescott, E; Lange, P; Vestbo, J

    1997-01-01

    BACKGROUND: Women are more often admitted to hospital for asthma than men. A study was undertaken to determine whether this is caused by gender differences in the prevalence or severity of the disease. METHODS: Admissions to hospital for asthma in 13,540 subjects were followed from 1977 to 1993......% confidence interval 1.2 to 2.4). This increased risk was not due to misclassification of chronic obstructive pulmonary disease (COPD) as asthma. CONCLUSIONS: These findings indicate gender-related differences in either the severity, perception, or management of asthma....

  8. Prevalence of subclinical hypothyroidism in pregnancy in Saudi Arabia.

    Science.gov (United States)

    Al Shanqeeti, Shatha A; Alkhudairy, Yasser N; Alabdulwahed, Alwaleed A; Ahmed, Anwar E; Al-Adham, Maysoon S; Mahmood, Naveed M

    2018-03-01

    To estimate the prevalence of subclinical hypothyroidism (SCH) in Saudi Arabia and assess the need for an SCH screening program. Methods: This cross-sectional study was conducted at King Abdulaziz Medical City and the Khashmulaan Clinic at the National Guard Health Affairs, Riyadh, Saudi Arabia in August 2016. All women attending the antenatal clinics were  invited to participate in the study. In addition, data were retrieved from the files of pregnant women who had been screened for hypothyroidism from January 2016 to August 2016. A total of 384 pregnant women were included in the study. Results: The prevalence of SCH in pregnant women in this study was 50/384 (13%) with 95% confidence intervals (CIs): 9.82%-16.80%. Pregnant women who were randomly screened using a survey (n=127) were 3 times more likely (OR: 3.1; 95% CI:  1.182 to 8.704, p=0.022) to have SCH compared to pregnant women who were screened based on their physician's judgement (n=257). Results showed older age (≥40 years) was associated with an insignificant decrease in the risk of SCH. Conclusion: Random screening for SCH in pregnant women showed a higher prevalence in comparison to women who were screened as a result of physician referrals. The results highlight the urgent need for larger studies to investigate the prevalence of SCH as well as the need for an SCH screening program.

  9. Autism spectrum disorders are prevalent among patients with dystrophinopathies.

    Science.gov (United States)

    Fujino, Haruo; Saito, Toshio; Matsumura, Tsuyoshi; Shibata, Saki; Iwata, Yuko; Fujimura, Harutoshi; Imura, Osamu

    2018-03-28

    Recent studies have reported a higher prevalence of autism spectrum disorders among patients with dystrophinopathies. The aim of this study was to investigate the prevalence of autism spectrum disorder (ASD) among those with dystrophinopathies. The possible role of dystrophin isoforms in patients was also explored. Fifty-six patients recruited from Toneyama National Hospital were included in this study (mean age = 12.9 years, SD = 5.2 years). Autistic symptoms were evaluated using the Pervasive Developmental Disorders/Autism Spectrum Disorders Rating Scale (PARS), a clinician rating scale. Eleven patients (19.6%; 95% confidence interval 10.2-32.4) met the criteria for ASD based on their PARS scores. Patients were separated into two groups based on the cumulative loss of dystrophin isoforms predicted from the mutation location. The prevalence of ASD was examined between these groups. Infantile and current autistic symptoms did not differ between the groups, except on one subscale of the PARS. This study revealed that there was a high prevalence of ASD in patients with dystrophinopathies.

  10. The prevalence of posttraumatic stress among women requesting induced abortion.

    Science.gov (United States)

    Wallin Lundell, Inger; Sundström Poromaa, Inger; Frans, Orjan; Helström, Lotti; Högberg, Ulf; Moby, Lena; Nyberg, Sigrid; Sydsjö, Gunilla; Georgsson Öhman, Susanne; Östlund, Ingrid; Skoog Svanberg, Agneta

    2013-12-01

    To describe the prevalence and pattern of traumatic experiences, to assess the prevalence of posttraumatic stress disorder (PTSD) and posttraumatic stress symptoms (PTSS), to identify risk factors for PTSD and PTSS, and to analyse the association of PTSD and PTSS with concomitant anxiety and depressive symptoms in women requesting induced abortion. A Swedish multi-centre study of women requesting an induced abortion. The Screen Questionnaire - Posttraumatic Stress Disorder was used for research diagnoses of PTSD and PTSS. Anxiety and depressive symptoms were evaluated by the Hospital Anxiety and Depression Scale (HADS). Of the 1514 respondents, almost half reported traumatic experiences. Lifetime- and point prevalence of PTSD were 7% (95% confidence interval [CI]: 5.8-8.5) and 4% (95% CI: 3.1-5.2), respectively. The prevalence of PTSS was 23% (95% CI: 21.1-25.4). Women who reported symptoms of anxiety or depression when requesting abortion were more likely to have ongoing PTSD or PTSS. Also single-living women and smokers displayed higher rates of ongoing PTSD. Although PTSD is rare among women who request an induced abortion, a relatively high proportion suffers from PTSS. Abortion seeking women with trauma experiences and existing or preexisting mental disorders need more consideration and alertness when counselled for termination.

  11. Prevalence of metabolic syndrome in Iran: A 2011 update.

    Science.gov (United States)

    Noshad, Sina; Abbasi, Mehrshad; Etemad, Koorosh; Meysamie, Alipasha; Afarideh, Mohsen; Khajeh, Elias; Asgari, Fereshteh; Mousavizadeh, Mostafa; Rafei, Ali; Neishaboury, Mohamadreza; Ghajar, Alireza; Nakhjavani, Manouchehr; Koohpayehzadeh, Jalil; Esteghamati, Alireza

    2017-05-01

    The aim of the present study was to determine the prevalence of metabolic syndrome and its individual components among the Iranian adult population in 2011 and to investigate changes between 2007 and 2011. Data from two rounds of the Surveillance of Risk Factors of Non-communicable Diseases national surveys conducted in 2007 and 2011 were pooled. Metabolic syndrome was defined according to International Diabetes Federation criteria. In 2007, the prevalence of metabolic syndrome among adults aged 25-64 years was 35.95 (95% confidence interval [CI] 34.27-37.63), which decreased to 32.96 (95% CI 30.73-35.18) in 2011 (P = 0.0108). Despite this overall decline, the prevalence of central obesity (P = 0.1383), raised triglycerides (P = 0.3058), and reduced high-density lipoprotein cholesterol (HDL-C; P = 0.5595) remained constant. There was a trend towards a decline in the proportion of individuals with increased blood pressure (P = 0.0978), and the proportion of adults with increased fasting plasma glucose (FPG) increased (P metabolic syndrome has decreased slightly in Iran, although prevalence of increased FPG has increased significantly. One-third of the Iranian adult population is diagnosed with metabolic syndrome. © 2016 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and John Wiley & Sons Australia, Ltd.

  12. Prevalence of anemia in First Nations children of northwestern Ontario.

    Science.gov (United States)

    Whalen, E. A.; Caulfield, L. E.; Harris, S. B.

    1997-01-01

    OBJECTIVE: To estimate the prevalence of anemia among First Nations children of northwestern Ontario. DESIGN: Retrospective review of all hemoglobin determinations between 1990 and 1992 in the Sioux Lookout Zone. SETTING: The Sioux Lookout Zone Hospital, a secondary care referral hospital for 28 remote First Nations communities in northwestern Ontario, affiliated with the University of Toronto's Sioux Lookout Program. PARTICIPANTS: All First Nations children age 3 to 60 months who had produced venipuncture or fingerprick blood samples between 1990 and 1992 (614 children had a total of 1223 hemoglobin determinations). MAIN OUTCOME MEASURES: Prevalence of anemia by age, sex, geographical location, and diagnosis. Anemia was defined as a hemoglobin value less than 110g/L. RESULTS: Prevalence of anemia peaked in the age range of 6 to 24 months with prevalence rates of 51.7% to 79.3%. Conditions most commonly associated with anemia were respiratory tract infections. Children living in communities in the western part of the Sioux Lookout Zone were 1.64 times more likely to have anemia (95% confidence interval 1.15, 2.35) than children in the other communities. CONCLUSIONS: Anemia appears to be a serious public health problem among preschool children in the Sioux Lookout Zone. PMID:9111982

  13. Prevalence of undiagnosed atrial fibrillation and of that not being treated with anticoagulant drugs: the AFABE study.

    Science.gov (United States)

    Clua-Espuny, Josep L; Lechuga-Duran, Iñigo; Bosch-Princep, Ramón; Roso-Llorach, Albert; Panisello-Tafalla, Anna; Lucas-Noll, Jorgina; López-Pablo, Carles; Queralt-Tomas, Lluïsa; Giménez-Garcia, Emmanuel; González-Rojas, Núria; Gallofré López, Miquel

    2013-07-01

    Atrial fibrillation constitutes a serious public health problem because it can lead to complications. Thus, the management of this arrhythmia must include not only its treatment, but antithrombotic therapy as well. The main goal is to determine the proportion of cases of undiagnosed atrial fibrillation and the proportion of patients not being treated with oral anticoagulants. A multicenter, population-based, retrospective, cross-sectional, observational study. In all, 1043 participants over 60 years of age were randomly selected to undergo an electrocardiogram in a prearranged appointment. Demographic data, CHA2DS2-VASc and HAS-BLED scores, international normalized ratio results, and reasons for not receiving oral anticoagulant therapy were recorded. The overall prevalence of atrial fibrillation was 10.9% (95% confidence interval, 9.1%-12.8%), 20.1% of which had not been diagnosed previously. In the group with known atrial fibrillation, 23.5% of those with CHA2DS2-VASc≥2 were not receiving oral anticoagulant therapy, and 47.9% had a HAS-BLED score≥3. The odds ratio for not being treated with oral anticoagulation was 2.04 (95% confidence interval, 1.11-3.77) for women, 1.10 (95% confidence interval, 1.05-1.15) for more advanced age at diagnosis, and 8.61 (95% confidence interval 2.38-31.0) for a CHA2DS2-VASc score<2. Cognitive impairment (15.2%) was the main reason for not receiving oral anticoagulant therapy. The prevalence of previously undiagnosed atrial fibrillation in individuals over 60 years of age is 20.1%, and 23.5% of those who have been diagnosed receive no treatment with oral anticoagulants. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  14. Prevalence and incidence of epilepsy: A systematic review and meta-analysis of international studies.

    Science.gov (United States)

    Fiest, Kirsten M; Sauro, Khara M; Wiebe, Samuel; Patten, Scott B; Kwon, Churl-Su; Dykeman, Jonathan; Pringsheim, Tamara; Lorenzetti, Diane L; Jetté, Nathalie

    2017-01-17

    To review population-based studies of the prevalence and incidence of epilepsy worldwide and use meta-analytic techniques to explore factors that may explain heterogeneity between estimates. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards were followed. We searched MEDLINE and EMBASE for articles published on the prevalence or incidence of epilepsy since 1985. Abstract, full-text review, and data abstraction were conducted in duplicate. Meta-analyses and meta-regressions were used to explore the association between prevalence or incidence, age group, sex, country level income, and study quality. A total of 222 studies were included (197 on prevalence, 48 on incidence). The point prevalence of active epilepsy was 6.38 per 1,000 persons (95% confidence interval [95% CI] 5.57-7.30), while the lifetime prevalence was 7.60 per 1,000 persons (95% CI 6.17-9.38). The annual cumulative incidence of epilepsy was 67.77 per 100,000 persons (95% CI 56.69-81.03) while the incidence rate was 61.44 per 100,000 person-years (95% CI 50.75-74.38). The prevalence of epilepsy did not differ by age group, sex, or study quality. The active annual period prevalence, lifetime prevalence, and incidence rate of epilepsy were higher in low to middle income countries. Epilepsies of unknown etiology and those with generalized seizures had the highest prevalence. This study provides a comprehensive synthesis of the prevalence and incidence of epilepsy from published international studies and offers insight into factors that contribute to heterogeneity between estimates. Significant gaps (e.g., lack of incidence studies, stratification by age groups) were identified. Standardized reporting of future epidemiologic studies of epilepsy is needed. © 2016 American Academy of Neurology.

  15. The Relationship Between Confidence and Performance Throughout a Competitive Season

    OpenAIRE

    Skinner, Benjiman R.

    2013-01-01

    The importance of understanding how confidence varies across time has been encouraged by sport confidence researchers (Vealey & Chase, 2008). The purpose of this study was to examine the relationship between confidence and performance throughout an entire competitive season. Two levels of confidence consistent to team sports were analyzed. Team and coach confidence were collected through the Collective Efficacy Questionnaire for Sport (CEQS) and Coaching Efficacy Scale (CES) respectively. Two...

  16. Eyewitness confidence : the relation between accuracy and confidence in episodic memory

    NARCIS (Netherlands)

    Odinot, Geralda

    2008-01-01

    Many decisions in the legal system are based on eyewitness evidence. It seems to be a matter of common sense that the level of confidence expressed by a witness can be used as a diagnostic tool to discriminate between accurate and inaccurate memories. Contrary to this general belief, the bulk of

  17. Calibration interval technical basis document

    International Nuclear Information System (INIS)

    Chiaro, P.J. Jr.

    1998-09-01

    This document provides a method for the establishment and evaluation of calibration intervals for radiation protection instrumentation. This document is applicable to instrumentation used by personnel at US Department of Energy (DOE) facilities for the measurement of radioactive contamination and the measurement and monitoring of radiation fields for protection of personnel and the environment. Special calibrations are not addressed by this document and should be handled separately

  18. Haemostatic reference intervals in pregnancy.

    Science.gov (United States)

    Szecsi, Pal B; Jørgensen, Maja; Klajnbard, Anna; Andersen, Malene R; Colov, Nina P; Stender, Steen

    2010-04-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S, and protein C and in a subgroup of 186 women in addition for prothrombin time (PT), Owren and Quick PT, protein S activity, and total protein S and coagulation factors II, V, VII, VIII, IX, X, XI, and XII. The level of coagulation factors II, V, X, XI, XII and antithrombin, protein C, aPTT, PT remained largely unchanged during pregnancy, delivery, and postpartum and were within non-pregnant reference intervals. However, levels of fibrinogen, D-dimer, and coagulation factors VII, VIII, and IX increased markedly. Protein S activity decreased substantially, while free protein S decreased slightly and total protein S was stable. Gestational age-specific reference values are essential for the accurate interpretation of a subset of haemostatic tests during pregnancy, delivery, and puerperium.

  19. The 2012 Retirement Confidence Survey: job insecurity, debt weigh on retirement confidence, savings.

    Science.gov (United States)

    Helman, Ruth; Copeland, Craig; VanDerhei, Jack

    2012-03-01

    Americans' confidence in their ability to retire comfortably is stagnant at historically low levels. Just 14 percent are very confident they will have enough money to live comfortably in retirement (statistically equivalent to the low of 13 percent measured in 2011 and 2009). Employment insecurity looms large: Forty-two percent identify job uncertainty as the most pressing financial issue facing most Americans today. Worker confidence about having enough money to pay for medical expenses and long-term care expenses in retirement remains well below their confidence levels for paying basic expenses. Many workers report they have virtually no savings and investments. In total, 60 percent of workers report that the total value of their household's savings and investments, excluding the value of their primary home and any defined benefit plans, is less than $25,000. Twenty-five percent of workers in the 2012 Retirement Confidence Survey say the age at which they expect to retire has changed in the past year. In 1991, 11 percent of workers said they expected to retire after age 65, and by 2012 that has grown to 37 percent. Regardless of those retirement age expectations, and consistent with prior RCS findings, half of current retirees surveyed say they left the work force unexpectedly due to health problems, disability, or changes at their employer, such as downsizing or closure. Those already in retirement tend to express higher levels of confidence than current workers about several key financial aspects of retirement. Retirees report they are significantly more reliant on Social Security as a major source of their retirement income than current workers expect to be. Although 56 percent of workers expect to receive benefits from a defined benefit plan in retirement, only 33 percent report that they and/or their spouse currently have such a benefit with a current or previous employer. More than half of workers (56 percent) report they and/or their spouse have not tried

  20. Contraceptive confidence and timing of first birth in Moldova: an event history analysis of retrospective data.

    Science.gov (United States)

    Lyons-Amos, Mark; Padmadas, Sabu S; Durrant, Gabriele B

    2014-08-11

    To test the contraceptive confidence hypothesis in a modern context. The hypothesis is that women using effective or modern contraceptive methods have increased contraceptive confidence and hence a shorter interval between marriage and first birth than users of ineffective or traditional methods. We extend the hypothesis to incorporate the role of abortion, arguing that it acts as a substitute for contraception in the study context. Moldova, a country in South-East Europe. Moldova exhibits high use of traditional contraceptive methods and abortion compared with other European countries. Data are from a secondary analysis of the 2005 Moldovan Demographic and Health Survey, a nationally representative sample survey. 5377 unmarried women were selected. The outcome measure was the interval between marriage and first birth. This was modelled using a piecewise-constant hazard regression, with abortion and contraceptive method types as primary variables along with relevant sociodemographic controls. Women with high contraceptive confidence (modern method users) have a higher cumulative hazard of first birth 36 months following marriage (0.88 (0.87 to 0.89)) compared with women with low contraceptive confidence (traditional method users, cumulative hazard: 0.85 (0.84 to 0.85)). This is consistent with the contraceptive confidence hypothesis. There is a higher cumulative hazard of first birth among women with low (0.80 (0.79 to 0.80)) and moderate abortion propensities (0.76 (0.75 to 0.77)) than women with no abortion propensity (0.73 (0.72 to 0.74)) 24 months after marriage. Effective contraceptive use tends to increase contraceptive confidence and is associated with a shorter interval between marriage and first birth. Increased use of abortion also tends to increase contraceptive confidence and shorten birth duration, although this effect is non-linear-women with a very high use of abortion tend to have lengthy intervals between marriage and first birth. Published by

  1. National HIV prevalence estimates for sub-Saharan Africa: controlling selection bias with Heckman-type selection models

    Science.gov (United States)

    Hogan, Daniel R; Salomon, Joshua A; Canning, David; Hammitt, James K; Zaslavsky, Alan M; Bärnighausen, Till

    2012-01-01

    Objectives Population-based HIV testing surveys have become central to deriving estimates of national HIV prevalence in sub-Saharan Africa. However, limited participation in these surveys can lead to selection bias. We control for selection bias in national HIV prevalence estimates using a novel approach, which unlike conventional imputation can account for selection on unobserved factors. Methods For 12 Demographic and Health Surveys conducted from 2001 to 2009 (N=138 300), we predict HIV status among those missing a valid HIV test with Heckman-type selection models, which allow for correlation between infection status and participation in survey HIV testing. We compare these estimates with conventional ones and introduce a simulation procedure that incorporates regression model parameter uncertainty into confidence intervals. Results Selection model point estimates of national HIV prevalence were greater than unadjusted estimates for 10 of 12 surveys for men and 11 of 12 surveys for women, and were also greater than the majority of estimates obtained from conventional imputation, with significantly higher HIV prevalence estimates for men in Cote d'Ivoire 2005, Mali 2006 and Zambia 2007. Accounting for selective non-participation yielded 95% confidence intervals around HIV prevalence estimates that are wider than those obtained with conventional imputation by an average factor of 4.5. Conclusions Our analysis indicates that national HIV prevalence estimates for many countries in sub-Saharan African are more uncertain than previously thought, and may be underestimated in several cases, underscoring the need for increasing participation in HIV surveys. Heckman-type selection models should be included in the set of tools used for routine estimation of HIV prevalence. PMID:23172342

  2. Comparison between two population-based hepatitis B serosurveys with an 8-year interval in Shandong Province, China.

    Science.gov (United States)

    Liu, Jiaye; Lv, Jingjing; Yan, Bingyu; Feng, Yi; Song, Lizhi; Xu, Aiqiang; Zhang, Li; Yan, Yongping

    2017-08-01

    Tremendous progress has been made in hepatitis B virus (HBV) prevention and control in the last 30 years in China, but it continues to be a major public health problem. The most recently reported population-based seroepidemiological survey on HBV in Shandong Province in China was published in 2006, and an updated baseline for HBV prevalence was badly needed in the province to identify the change in HBV epidemiology in the last decade. Two population-based cross-sectional serosurveys were performed among the population aged 1-59 years in the same sample areas in Shandong Province, China in 2006 and 2014, respectively. Data on demographic characteristics were collected. A blood sample was obtained from each person and was tested for hepatitis B surface antigen (HBsAg), antibody against HBsAg (anti-HBs), and antibody against hepatitis B core antigen (anti-HBc). Overall, the prevalence rates of HBsAg, anti-HBs, and anti-HBc were 3.39% (95% confidence interval (CI) 2.51-4.26), 44.96% (95% CI 41.34-48.57), and 24.45% (95% CI 22.19-26.71), respectively, among the population aged 1-59 years in the 2006 serovsurvey; the corresponding prevalence rates were 2.49% (95% CI 1.81-3.17), 48.27% (95% CI 45.63-50.92), and 22.56% (95% CI 20.14-24.97), respectively, in 2014. The prevalence rates of HBsAg and anti-HBc were lower in 2014 than in 2006. Conversely, the prevalence of anti-HBs showed an increase. However, none of these differences were statistically significant (all p>0.05). The prevalence of HBsAg showed an increase among persons aged 20-24 years in 2014 (3.83%) compared with 2006 (2.98%) (t=0.45, p=0.67). Among all occupation groups, the prevalence of HBsAg was lower in 2014 than in 2006, while the prevalence of anti-HBc showed moderate increases in students and farmers (all p>0.05). The prevalence of HBsAg decreased more obviously in urban areas (65.49%) than rural areas (7.07%) from 2006 to 2014. The epidemiology of HBV infection has changed in Shandong Province, China

  3. ERICA: prevalence of asthma in Brazilian adolescents.

    Science.gov (United States)

    Kuschnir, Fábio Chigres; Gurgel, Ricardo Queiroz; Solé, Dirceu; Costa, Eduardo; Felix, Mara Morelo Rocha; de Oliveira, Cecília Lacroix; de Vasconcellos, Maurício Teixeira Leite; Kuschnir, Maria Cristina Caetano

    2016-02-01

    OBJECTIVE To describe the prevalence of asthma and physician-diagnosed asthma in Brazilian adolescents. METHODS Cross-sectional, national, school-based study with adolescents from 12 to 17 years old, participants in the Study of Cardiovascular Risks in Adolescents (ERICA). The study stratified the sample by region and grouped according to schools and classes with representativeness to the set of cities with more than 100,000 inhabitants of the Country, macro-regions, capitals, and Federal District. A questionnaire collected data through a self-filled in method. We calculated the prevalences and their confidence intervals of 95% (95%CI) according to sex, age group, type of school and skin color. RESULTS Between 2013 and 2014, 74,589 adolescents were evaluated, 55.3% of the female sex. The total prevalence of active asthma was of 13.1% (95%CI 12.1-13.9), being higher in girls (14.8%; 95%CI 13.7-16.0) when compared to boys (11.2%; 95%CI 10.3-12.2) in all geographical strata examined. It was also higher between students of private schools (15.9%; 95%CI 14.2-17.7) when compared to public ones (12.4%; 95%CI 11.4-13.4). It was higher in the Southeast region (14.5%; 95%CI 12.9-16.1), and in the city of Sao Paulo (16.7%; 95%CI 14.7-18.7). The lowest prevalence was observed in North region (9.7%; 95%CI 9.7-10.5), and in Teresina (6.3%; 95%CI 4.9-7.7). The prevalence of physician-diagnosed asthma was of 8.7% (95%CI 8.2-9.1); higher in the North region (13.5%; 95%CI 12.7-14.2), and in Porto Alegre (19.8%; 95%CI 17.5-22.3). It was lower in the Midwest (6.9%; 95%CI 6.0-7.8), and in Cuiaba (4.8%; 95%CI 3.8-5.9). We found no significant difference in the expression of this rate between the sexes, as well as in other variables evaluated by the study. CONCLUSIONS The prevalence of asthma in Brazilian adolescents is high. Rates of active asthma and physician-diagnosed asthma vary widely in different regions and capitals evaluated by the ERICA. These results may assist in the

  4. ERICA: prevalence of asthma in Brazilian adolescents

    Science.gov (United States)

    Kuschnir, Fábio Chigres; Gurgel, Ricardo Queiroz; Solé, Dirceu; Costa, Eduardo; Felix, Mara Morelo Rocha; de Oliveira, Cecília Lacroix; de Vasconcellos, Maurício Teixeira Leite; Kuschnir, Maria Cristina Caetano

    2016-01-01

    ABSTRACT OBJECTIVE To describe the prevalence of asthma and physician-diagnosed asthma in Brazilian adolescents. METHODS Cross-sectional, national, school-based study with adolescents from 12 to 17 years old, participants in the Study of Cardiovascular Risks in Adolescents (ERICA). The study stratified the sample by region and grouped according to schools and classes with representativeness to the set of cities with more than 100,000 inhabitants of the Country, macro-regions, capitals, and Federal District. A questionnaire collected data through a self-filled in method. We calculated the prevalences and their confidence intervals of 95% (95%CI) according to sex, age group, type of school and skin color. RESULTS Between 2013 and 2014, 74,589 adolescents were evaluated, 55.3% of the female sex. The total prevalence of active asthma was of 13.1% (95%CI 12.1-13.9), being higher in girls (14.8%; 95%CI 13.7-16.0) when compared to boys (11.2%; 95%CI 10.3-12.2) in all geographical strata examined. It was also higher between students of private schools (15.9%; 95%CI 14.2-17.7) when compared to public ones (12.4%; 95%CI 11.4-13.4). It was higher in the Southeast region (14.5%; 95%CI 12.9-16.1), and in the city of Sao Paulo (16.7%; 95%CI 14.7-18.7). The lowest prevalence was observed in North region (9.7%; 95%CI 9.7-10.5), and in Teresina (6.3%; 95%CI 4.9-7.7). The prevalence of physician-diagnosed asthma was of 8.7% (95%CI 8.2-9.1); higher in the North region (13.5%; 95%CI 12.7-14.2), and in Porto Alegre (19.8%; 95%CI 17.5-22.3). It was lower in the Midwest (6.9%; 95%CI 6.0-7.8), and in Cuiaba (4.8%; 95%CI 3.8-5.9). We found no significant difference in the expression of this rate between the sexes, as well as in other variables evaluated by the study. CONCLUSIONS The prevalence of asthma in Brazilian adolescents is high. Rates of active asthma and physician-diagnosed asthma vary widely in different regions and capitals evaluated by the ERICA. These results may assist in the

  5. Global Prevalence of Celiac Disease: Systematic Review and Meta-analysis.

    Science.gov (United States)

    Singh, Prashant; Arora, Ananya; Strand, Tor A; Leffler, Daniel A; Catassi, Carlo; Green, Peter H; Kelly, Ciaran P; Ahuja, Vineet; Makharia, Govind K

    2018-03-15

    Celiac disease is a major public health problem worldwide. Although initially it was reported from countries with predominant Caucasian populations, it now has been reported from other parts of the world. The exact global prevalence of celiac disease is not known. We conducted a systematic review and meta-analysis to estimate the global prevalence of celiac disease. We searched Medline, PubMed, and EMBASE for the keywords celiac disease, celiac, celiac disease, tissue transglutaminase antibody, anti-endomysium antibody, endomysial antibody, and prevalence for studies published from January 1991 through March 2016. Each article was cross-referenced with the words Asia, Europe, Africa, South America, North America, and Australia. The diagnosis of celiac disease was based on European Society of Pediatric Gastroenterology, Hepatology, and Nutrition guidelines. Of 3843 articles, 96 articles were included in the final analysis. The pooled global prevalence of celiac disease was 1.4% (95% confidence interval, 1.1%-1.7%) in 275,818 individuals, based on positive results from tests for anti-tissue transglutaminase and/or anti-endomysial antibodies (called seroprevalence). The pooled global prevalence of biopsy-confirmed celiac disease was 0.7% (95% confidence interval, 0.5%-0.9%) in 138,792 individuals. The prevalence values for celiac disease were 0.4% in South America, 0.5% in Africa and North America, 0.6% in Asia, and 0.8% in Europe and Oceania; the prevalence was higher in female vs male individuals (0.6% vs 0.4%; P celiac disease was significantly greater in children than adults (0.9% vs 0.5%; P celiac disease to be reported worldwide. The prevalence of celiac disease based on serologic test results is 1.4% and based on biopsy results is 0.7%. The prevalence of celiac disease varies with sex, age, and location. There is a need for population-based prevalence studies in many countries. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  6. Sources of sport confidence, imagery type and performance among competitive athletes: the mediating role of sports confidence.

    Science.gov (United States)

    Levy, A R; Perry, J; Nicholls, A R; Larkin, D; Davies, J

    2015-01-01

    This study explored the mediating role of sport confidence upon (1) sources of sport confidence-performance relationship and (2) imagery-performance relationship. Participants were 157 competitive athletes who completed state measures of confidence level/sources, imagery type and performance within one hour after competition. Among the current sample, confirmatory factor analysis revealed appropriate support for the nine-factor SSCQ and the five-factor SIQ. Mediational analysis revealed that sport confidence had a mediating influence upon the achievement source of confidence-performance relationship. In addition, both cognitive and motivational imagery types were found to be important sources of confidence, as sport confidence mediated imagery type- performance relationship. Findings indicated that athletes who construed confidence from their own achievements and report multiple images on a more frequent basis are likely to benefit from enhanced levels of state sport confidence and subsequent performance.

  7. Incidence and prevalence of systemic lupus erythematosus among the native Arab population in UAE.

    Science.gov (United States)

    Al Dhanhani, A M; Agarwal, M; Othman, Y S; Bakoush, O

    2017-05-01

    Background and objectives There is a paucity of information about the epidemiology of systemic lupus erythematosus (SLE) amongst Arabs. The objective of this study was to determine the incidence and prevalence of SLE among the native Arab population of United Arab Emirates (UAE). Methods Patients with SLE were identified from three sources: medical records of two local tertiary hospitals (four years; 2009 to 2012), laboratory requests for serum double stranded deoxyribonucleic acid and serum anti-nuclear antibody and confirmed histopathologic diagnosis of SLE (skin and kidney biopsy specimens). All the patients identified with SLE met the criteria of the American College of Rheumatology. Incidence and prevalence were calculated using the state records of the UAE native population as the denominator. The age-adjusted incidence was calculated by direct standardization using the World Health Organization world standard population 2000-2025. Results Sixteen new cases (13 females and three males) fulfilled the American College of Rheumatology SLE criteria. The mean (±SD) age at time of diagnosis was 28.6 ± 12.4 years. The crude incidence ratio (per 100,000 population) was 3.5, 1.1, 2.1 and 2.1 in years 2009, 2010, 2011, 2012, respectively. The age-standardized incidence per 100,000 population for the four years was 8.6 (95% confidence interval 4.2-15.9). The age-standardized prevalence of SLE among the native population according to the 2012 population consensus was 103/100,000 population (95% confidence interval 84.5-124.4). Conclusion The age-adjusted incidence and prevalence among UAE Arabs is higher than has been reported among most other Caucasian populations. Furthermore, the prevalence of SLE in UAE seems much higher than other similar Arab countries in the Gulf region.

  8. The Prevalence of Self-Reported Stroke in the Australian National Eye Health Survey.

    Science.gov (United States)

    Keel, Stuart; Foreman, Joshua; Xie, Jing; Taylor, Hugh R; Dirani, Mohamed

    2017-07-01

    The study aimed to determine the prevalence of and risk factors for self-reported stroke in Indigenous and non-Indigenous Australians. In this national eye study, 1738 Indigenous Australians (41.1% male) aged 40-92 years and 3098 non-Indigenous Australians (46.4% male) aged 50-98 years from 30 randomly selected sites, stratified by remoteness, were recruited and examined. Sociodemographic information and a history of stroke, diabetes, and ocular health were obtained using an interviewer-administered questionnaire. The crude prevalence of self-reported stroke was 5.04% (156 of 3098, 95% confidence interval: 4.29%-5.87%) for non-Indigenous Australians and 8.75% (152 of 1738, 95% confidence interval: 7.46%-10.17%) for Indigenous Australians (P self-reported stroke for non-Indigenous and Indigenous Australians was 4.23% and 12.72%, respectively. The prevalence of stroke increased significantly with age for both Indigenous (odds ratio = 1.06 per year, P ≤ .001) and non-Indigenous Australians (odds ratio = 1.04 per year, P ≤ .001), with the Indigenous prevalence being higher than that of the non-Indigenous group at every age. The prevalence of self-reported stroke was 3 times higher in Indigenous Australians than in non-Indigenous Australians. This disparity is consistent with previous reports, highlighting the need for intensified prevention and support services to reduce the burden of stroke on Indigenous Australians. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  9. Prevalence rates and epidemiological risk factors for astigmatism in Singapore school children.

    Science.gov (United States)

    Tong, Louis; Saw, Seang-Mei; Carkeet, Andrew; Chan, Wai-Ying; Wu, Hui-Min; Tan, Donald

    2002-09-01

    This study examined the prevalence rate of astigmatism and its epidemiological risk factors in Singapore school children. In a study of school children aged 7 to 9 years old in two schools in Singapore in 1999, a detailed questionnaire was administered to parents regarding reading or close-work habits, past history of close-work, family history, and socioeconomic factors. Cycloplegic refraction was performed five times in each eye. Defining astigmatism as worse than or equal to 0.5, 0.75, and 1 D cylinder in the right eye, the prevalence of astigmatism was calculated. The study population consisted of 1028 children. The prevalence rate of astigmatism (worse than or equal to 1 D cylinder) was 19.2% (95% confidence interval, 16.8 to 21.6). This was not different between genders, ethnic groups, or age (p > 0.05). With-the-rule astigmatism was more common than against-the-rule astigmatism. The prevalence of astigmatism and myopia was 9.8% (95% confidence interval, 8.0 to 11.6). A high AC/A ratio was associated (p = 0.003) with astigmatism, even after exclusion of myopic children. On vectorial analysis, J0 and J45 were associated with the number of hours of playing video games, whereas J45 was also associated with computer use. Only J45 was associated to male gender, a high AC/A ratio, and a family history of myopia. The prevalence rate of astigmatism (> or = 1 D) was 19%. Playing video games and computer use may be associated with astigmatism severity, although the presence of astigmatism (> or = 1 D) was not associated with any nearwork factors. A family history of myopia was associated with oblique astigmatism severity. A high AC/A ratio is associated with astigmatism, and this requires further investigation.

  10. Vaccination Confidence and Parental Refusal/Delay of Early Childhood Vaccines.

    Directory of Open Access Journals (Sweden)

    Melissa B Gilkey

    Full Text Available To support efforts to address parental hesitancy towards early childhood vaccination, we sought to validate the Vaccination Confidence Scale using data from a large, population-based sample of U.S. parents.We used weighted data from 9,354 parents who completed the 2011 National Immunization Survey. Parents reported on the immunization history of a 19- to 35-month-old child in their households. Healthcare providers then verified children's vaccination status for vaccines including measles, mumps, and rubella (MMR, varicella, and seasonal flu. We used separate multivariable logistic regression models to assess associations between parents' mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status.A substantial minority of parents reported a history of vaccine refusal (15% or delay (27%. Vaccination confidence was negatively associated with refusal of any vaccine (odds ratio [OR] = 0.58, 95% confidence interval [CI], 0.54-0.63 as well as refusal of MMR, varicella, and flu vaccines specifically. Negative associations between vaccination confidence and measures of vaccine delay were more moderate, including delay of any vaccine (OR = 0.81, 95% CI, 0.76-0.86. Vaccination confidence was positively associated with having received vaccines, including MMR (OR = 1.53, 95% CI, 1.40-1.68, varicella (OR = 1.54, 95% CI, 1.42-1.66, and flu vaccines (OR = 1.32, 95% CI, 1.23-1.42.Vaccination confidence was consistently associated with early childhood vaccination behavior across multiple vaccine types. Our findings support expanding the application of the Vaccination Confidence Scale to measure vaccination beliefs among parents of young children.

  11. Vaccination Confidence and Parental Refusal/Delay of Early Childhood Vaccines.

    Science.gov (United States)

    Gilkey, Melissa B; McRee, Annie-Laurie; Magnus, Brooke E; Reiter, Paul L; Dempsey, Amanda F; Brewer, Noel T

    2016-01-01

    To support efforts to address parental hesitancy towards early childhood vaccination, we sought to validate the Vaccination Confidence Scale using data from a large, population-based sample of U.S. parents. We used weighted data from 9,354 parents who completed the 2011 National Immunization Survey. Parents reported on the immunization history of a 19- to 35-month-old child in their households. Healthcare providers then verified children's vaccination status for vaccines including measles, mumps, and rubella (MMR), varicella, and seasonal flu. We used separate multivariable logistic regression models to assess associations between parents' mean scores on the 8-item Vaccination Confidence Scale and vaccine refusal, vaccine delay, and vaccination status. A substantial minority of parents reported a history of vaccine refusal (15%) or delay (27%). Vaccination confidence was negatively associated with refusal of any vaccine (odds ratio [OR] = 0.58, 95% confidence interval [CI], 0.54-0.63) as well as refusal of MMR, varicella, and flu vaccines specifically. Negative associations between vaccination confidence and measures of vaccine delay were more moderate, including delay of any vaccine (OR = 0.81, 95% CI, 0.76-0.86). Vaccination confidence was positively associated with having received vaccines, including MMR (OR = 1.53, 95% CI, 1.40-1.68), varicella (OR = 1.54, 95% CI, 1.42-1.66), and flu vaccines (OR = 1.32, 95% CI, 1.23-1.42). Vaccination confidence was consistently associated with early childhood vaccination behavior across multiple vaccine types. Our findings support expanding the application of the Vaccination Confidence Scale to measure vaccination beliefs among parents of young children.

  12. The incidence and prevalence of Huntington's disease: a systematic review and meta-analysis.

    Science.gov (United States)

    Pringsheim, Tamara; Wiltshire, Katie; Day, Lundy; Dykeman, Jonathan; Steeves, Thomas; Jette, Nathalie

    2012-08-01

    Huntington's disease (HD) is a rare, neurodegenerative disorder characterized by chorea, behavioral manifestations, and dementia. The aim of this study was to estimate the incidence and prevalence of HD through a systematic review of the literature. Medline and Embase databases were searched using terms specific to HD as well as studies of incidence, prevalence, and epidemiology. All studies reporting the incidence and/or prevalence of HD were included. Twenty original research articles were included. Eight studies examined incidence, and 17 studies examined prevalence. Meta-analysis of data from four incidence studies revealed an incidence of 0.38 per 100,000 per year (95% confidence interval [CI]: 0.16, 0.94). Lower incidence was reported in the Asian studies (n = 2), compared to the studies performed in Europe, North America, and Australia (n = 6). The worldwide service-based prevalence of HD, based on a meta-analysis (n = 13 studies), was 2.71 per 100,000 (95% CI: 1.55-4.72). Eleven studies were conducted in Europe, North American, and Australia, with an overall prevalence of 5.70 per 100,000 (95% CI: 4.42-7.35). Three studies were conducted in Asia, with an overall prevalence of 0.40 per 100,000 (95% CI: 0.26-0.61). Metaregression revealed a significantly lower prevalence of HD in Asia, compared to European, North American, and Australian populations. HD is a devastating neurodegenerative disorder with a higher prevalence in Europe, North America, and Australia than in Asia. The difference in prevalence of this genetic disorder can be largely explained by huntingtin gene haplotypes. Copyright © 2012 Movement Disorder Society.

  13. The prevalence of trichomoniasis in young adults in the United States.

    Science.gov (United States)

    Miller, William C; Swygard, Heidi; Hobbs, Marcia M; Ford, Carol A; Handcock, Mark S; Morris, Martina; Schmitz, John L; Cohen, Myron S; Harris, Kathleen Mullan; Udry, J Richard

    2005-10-01

    The prevalence of trichomoniasis in the general population of the United States is unknown. This study provides the first population-based prevalence estimates of trichomoniasis among young adults in the United States. The National Longitudinal Study of Adolescent Health (Add Health) is an ongoing prospective cohort study. In a cross-sectional analysis of Wave III of Add Health (N = 12,449), we determined the prevalence of trichomoniasis using a polymerase chain reaction assay. The estimated overall prevalence of trichomoniasis in U.S. young adults was 2.3% (95% confidence interval [CI], 1.8-2.7%). The prevalence was slightly higher among women (2.8%; 95% CI, 2.2-3.6%) than men (1.7%; 95% CI, 1.3-2.2%). The prevalence increased with age and varied by region, with the south having the highest prevalence (2.8%; 95% CI, 2.2-3.5%). The prevalence was highest among black women (10.5%; 95% CI, 8.3-13.3%) and lowest among white women (1.1%; 95% CI, 0.8-1.6%). Among men, the prevalence was highest among Native Americans (4.1%; 95% CI, 0.4-29.3%) and blacks (3.3%; 95% CI, 2.2-4.9%), and lowest among white men (1.3%; 95% CI, 0.9-1.8%). Trichomoniasis is moderately prevalent among the general U.S. population of young adults and disturbingly high among certain racial/ethnic groups.

  14. The association between smoking prevalence and eating disorders: a systematic review and meta-analysis.

    Science.gov (United States)

    Solmi, Marco; Veronese, Nicola; Sergi, Giuseppe; Luchini, Claudio; Favaro, Angela; Santonastaso, Paolo; Vancampfort, Davy; Correll, Christoph U; Ussher, Michael; Thapa-Chhetri, Nita; Fornaro, Michele; Stubbs, Brendon

    2016-11-01

    Cigarette smoking is associated with severe mental illness, including schizophrenia and bipolar disorder, and with morbidity and mortality, but the association with anorexia (AN), bulimia nervosa (BN) and binge eating disorder (BED) is unclear. This meta-analysis compared the odds of smoking in eating disorders (ED) (ED = AN or BN or BED) versus healthy controls (HC) and calculated the prevalence of smokers in people with ED. Three independent authors searched PubMed, MEDLINE and Scopus from database inception until 31 December 2015 for studies reporting data on life-time or current smoking prevalence in BED, BN and AN with or without control group. Meta-analyses were undertaken, calculating odds ratios (ORs) of life-time smoking in BED, BN, AN versus healthy controls (HCs) or prevalence of smoking in BED, BN and AN with 95% confidence intervals (CI). Thirty-one studies (ED = 8517, controls = 68 335) were meta-analysed. Compared with HCs, there were significantly more smokers among people with BN (life-time OR = 2.165) and BED (life-time OR = 1.792) but not AN (life-time OR = 0.927). BED was associated with smoking the most (life-time prevalence = 47.73%) followed by BN (life-time prevalence = 39.4%) and AN (life-time prevalence = 30.8%). In BN, life-time smoking prevalence was highest in Europe. In AN, higher age moderated both life-time and current smoking prevalence, and body mass index moderated higher life-time smoking prevalence. In BN, female sex moderated higher life-time smoking prevalence. People with binge eating disorder and bulimia nervosa are significantly more likely to be life-time smokers than healthy controls, which is not the case for anorexia nervosa. © 2016 Society for the Study of Addiction.

  15. The Prevalence of Burnout Among US Neurosurgery Residents.

    Science.gov (United States)

    Shakir, Hakeem J; McPheeters, Matthew J; Shallwani, Hussain; Pittari, Joseph E; Reynolds, Renée M

    2017-10-27

    Burnout is a syndrome of emotional exhaustion, depersonalization, and reduced personal accomplishment. Its prevalence among US physicians exceeds 50% and is higher among residents/fellows. This is important to the practice of neurosurgery, as burnout is associated with adverse physical health, increased risk of substance abuse, and increased medical errors. To date, no study has specifically addressed the prevalence of burnout among neurosurgery residents. To determine and compare the prevalence of burnout among US neurosurgery residents with published rates for residents/fellows and practicing physicians from other specialties. We surveyed 106 US neurosurgery residency training programs to perform a descriptive analysis of the prevalence of burnout among residents. Data on burnout among control groups were used to perform a cross-sectional analysis. Nonparametric tests assessed differences in burnout scores among neurosurgery residents, and the 2-tailed Fisher's exact test assessed burnout between neurosurgery residents and control populations. Of approximately 1200 US neurosurgery residents, 255 (21.3%) responded. The prevalence of burnout was 36.5% (95% confidence interval: 30.6%-42.7%). There was no significant difference in median burnout scores between gender (P = .836), age (P = .183), or postgraduate year (P = .963) among neurosurgery residents. Neurosurgery residents had a significantly lower prevalence of burnout (36.5%) than other residents/fellows (60.0%; P burnout than other residents/fellows and practicing physicians. The underlying causes for these findings were not assessed and are likely multifactorial. Future studies should address possible causes of these findings. Copyright © 2017 by the Congress of Neurological Surgeons

  16. Prevalence of insomnia and related impact.

    Science.gov (United States)

    Manjavong, Manchumad; Limpawattana, Panita; Mairiang, Pisaln; Anutrakulchai, Sirirat

    2016-08-01

    Background Sleep problem is a common geriatric condition that can result in various outcomes, both physical and mental, that reduce quality of life. The studies regarding the prevalence and impact of insomnia on daily activities in Thailand in pre-elderly and elderly adults are few. Objectives The primary objective of this study was to determine the prevalence of insomnia among pre-elderly and elderly populations and the secondary objective was to study the impact of insomnia on their daily lives. Methods This study included the participants from the urban middle class in the pre-retirement age of 50 years or older adults who worked for Khon Kaen University (KKU), Khon Kaen, Thailand, and their elderly relatives. Information on baseline characteristics, sleep problems, and outcomes were collected. Descriptive analytical statistics were used to analyze baseline data. Multivariate analysis was used to analyze associated factors of the impact of insomnia. Results A total of 491 participants were recruited. The prevalence of insomnia was 60%. The significant consequences related to insomnia were feeling unrefreshed (adjusted odds ratio (AOD) 2.22, 95% confidence interval (CI) 1.44-3.04), daytime sleepiness (AOD 2.04, 95% CI 1.29-3.22), need for a sedative drug (AOD 4.23, 95% CI 2.09-8.55), depression (AOD 4.74, 95% CI 1.73-13), and impaired attention (AOD 2.29, 95% CI 1.52-3.45). Conclusions Insomnia was found in the majority of pre-elderly and elderly participants and resulted in several poor outcomes. Early detection of insomnia may prevent some inevitable outcomes.

  17. [Prevalence of anosognosia in Alzheimer's disease].

    Science.gov (United States)

    Turró-Garriga, Oriol; Conde-Sala, Josep Lluís; Reñé-Ramírez, Ramón; López-Pousa, Secundino; Gascón-Bayarri, Jordi; Garre-Olmo, Josep

    2014-07-07

    Anosognosia is a disorder that affects the clinical presentation of Alzheimer's disease (AD), increasing in frequency with the evolution of AD. The objective was to determine the prevalence of anosognosia and analyze the associated factors and predictors. Multicenter transversal and observational study of 345 AD patients. Anosognosia was assessed by Anosognosia Questionnaire-Dementia and the evolutionary stage with the Global Deterioration Scale (GDS). Tests used were Mini-Mental State Examination, Disability Assessment for Dementia and Neuropsychiatric Inventory to assess cognition, functional status and neuropsychiatric symptoms, respectively. We adjusted linear regression models to determine the associated variables and binary logistic regression (RLog) to identify predictors of anosognosia. The overall prevalence of anosognosia was 46.7% (95% confidence interval [95% CI] 41.3 to 52.1). The prevalence in stages was 28.4% (GDS 4), 64.6% (GDS 5) and 91.4% (GDS 6). The RLog identified as predictors older age (odds ratio [OR] 1.04; 95% CI 1.01-1.09), lower functional capacity (OR 0.96; 95% CI 0.93-0.98), lower cognitive level (OR 0.9; 95% CI 0.88-0.99), and greater apathy (OR 1.1; 95% CI 1.03-1.18), disinhibition (OR 1.2; 95% CI 1.09-1.50), irritability (OR 1.1; 95% CI 1.09-1.50) and motor disorders (OR 1.2; 95% CI 1.09-1.50). Anosognosia increases with further deterioration. In patients with a mild impairment, predictor variables were apathy, disinhibition and motor disorders. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  18. Variational collocation on finite intervals

    International Nuclear Information System (INIS)

    Amore, Paolo; Cervantes, Mayra; Fernandez, Francisco M

    2007-01-01

    In this paper, we study a set of functions, defined on an interval of finite width, which are orthogonal and which reduce to the sinc functions when the appropriate limit is taken. We show that these functions can be used within a variational approach to obtain accurate results for a variety of problems. We have applied them to the interpolation of functions on finite domains and to the solution of the Schroedinger equation, and we have compared the performance of the present approach with others

  19. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A N; Sosnovtseva, Olga; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov exponent...... (LE) from point processes differ between the two models. We also consider the problem of estimating the second LE and the possibility to diagnose hyperchaotic behavior by processing spike trains. Since the second exponent is quite sensitive to the structure of the ISI series, we investigate...

  20. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A.N.; Sosnovtseva, Olga V.; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov exponent...... (LE) from paint processes differ between the two models. We also consider the problem of estimating the second LE and the possibility to diagnose hyperchaotic behavior by processing spike trains. Since the second exponent is quite sensitive to the structure of the ISI series, we investigate...

  1. Dijets at large rapidity intervals

    CERN Document Server

    Pope, B G

    2001-01-01

    Inclusive diet production at large pseudorapidity intervals ( Delta eta ) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large Delta eta in pp collisions at square root s = 1800 and 630 GeV using the DOE detector. The partonic cross section increases strongly with the size of Delta eta . The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of alpha /sub BFKL/(20 GeV) = 1.65 +or- 0.07.

  2. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    , and protein C and in a subgroup of 186 women in addition for prothrombin time (PT), Owren and Quick PT, protein S activity, and total protein S and coagulation factors II, V, VII, VIII, IX, X, XI, and XII. The level of coagulation factors II, V, X, XI, XII and antithrombin, protein C, aPTT, PT remained...... largely unchanged during pregnancy, delivery, and postpartum and were within non-pregnant reference intervals. However, levels of fibrinogen, D-dimer, and coagulation factors VII, VIII, and IX increased markedly. Protein S activity decreased substantially, while free protein S decreased slightly and total...

  3. Mathematical Foundations for a Theory of Confidence Structures

    Science.gov (United States)

    Balch, Michael Scott

    2012-01-01

    This paper introduces a new mathematical object: the confidence structure. A confidence structure represents inferential uncertainty in an unknown parameter by defining a belief function whose output is commensurate with Neyman-Pearson confidence. Confidence structures on a group of input variables can be propagated through a function to obtain a valid confidence structure on the output of that function. The theory of confidence structures is created by enhancing the extant theory of confidence distributions with the mathematical generality of Dempster-Shafer evidence theory. Mathematical proofs grounded in random set theory demonstrate the operative properties of confidence structures. The result is a new theory which achieves the holistic goals of Bayesian inference while maintaining the empirical rigor of frequentist inference. PMID:25190904

  4. Assessing Residents' Confidence in the Context of Pharmacotherapy Competence.

    Science.gov (United States)

    Rakofsky, Jeffrey J; Garlow, Steven J; Haroon, Ebrahim; Hermida, Adriana P; Young, John Q; Dunlop, Boadie W

    2017-06-01

    We aimed to determine whether residents' confidence initiating medications increased with the number of times they prescribed individual medications and to quantify the relationship between prescription frequency and gains in confidence. From July 2011 to June 2014, PGY-3 residents completed a survey of confidence levels at their psychopharmacology clinic orientation and then again 12 months later. The Emory Healthcare electronic medical record was used to identify all medications prescribed by each resident during their 12-month rotation and the frequency of these prescriptions. Confidence in initiating treatment with all medicines/medication classes increased over the 12-month period. For three of the medication classes for which residents indicated they were least confident at orientation, the number of prescriptions written during the year was significantly associated with an increase in confidence. Measuring resident confidence is a relevant and achievable outcome and provides data for educators regarding the amount of experience needed to increase confidence.

  5. Alternative confidence measure for local matching stereo algorithms

    CSIR Research Space (South Africa)

    Ndhlovu, T

    2009-11-01

    Full Text Available by analyzing the correlation curve produced during the matching process. The authors also test the confidence measure by developing an easily parallelized local matching algorithm, and use our confidence measure to filter out unreliable disparity estimates...

  6. Mental Health in Sport (MHS): Improving the Early Intervention Knowledge and Confidence of Elite Sport Staff

    Science.gov (United States)

    Sebbens, Joshua; Hassmén, Peter; Crisp, Dimity; Wensley, Kate

    2016-01-01

    Mental illnesses are as prevalent among elite athletes as in the general population. Despite this, there is little research examining how to enhance mental health literacy or helping behaviors in elite sport environments. A Mental Health in Sport (MHS) workshop was therefore developed and its effects on mental health literacy and confidence studied in 166 coaches and support staff working with elite athletes and teams in Australia. Results indicated that participants increased their knowledge of the signs and symptoms of common mental illnesses and were more confident in helping someone who may be experiencing a mental health problem. We conclude that even a very brief intervention can be effective in improving the mental health literacy and confidence of key persons in elite sport environments, and may promote early intervention and timely referral of elite athletes with mental health concerns to appropriate professionals. PMID:27445887

  7. Decreasing prevalence of the full metabolic syndrome but a persistently high prevalence of dyslipidemia among adult Arabs.

    Directory of Open Access Journals (Sweden)

    Nasser M Al-Daghri

    Full Text Available A decade has passed since metabolic syndrome (MetS was documented to be highly prevalent in the kingdom of Saudi Arabia. No follow-up epidemiologic study was done. This study aims to fill this gap. In this cross-sectional, observational study, a total of 2850 randomly selected Saudi adults aged 18-55 years were recruited. Subjects' information was generated from a database of more than 10,000 Saudi citizens from the existing Biomarkers Screening in Riyadh Program (RIYADH Cohort, Saudi Arabia. Anthropometrics included body mass index (BMI, blood pressure, as well as waist and hip circumferences. Fasting blood glucose and lipid profile were determined using routine laboratory procedures. The definition of ATP-III (NHANES III was used for the diagnosis of the full MetS. The overall prevalence of complete MetS was 35.3% [Confidence-Interval (CI 33.5-37.01]. Age-adjusted prevalence according to the European standard population is 37.0%. Low HDL-cholesterol was the most prevalent of all MetS risk factors, affecting 88.6% (CI 87.5-89.7 and hypertriglyceridemia the second most prevalent, affecting 34% (CI 32.3-35.7 of the subjects. The prevalence of the full MetS decreased from previous estimates but remains high, while dyslipidemia remains extremely high, affecting almost 90% of middle-aged Arabs. Screening for dyslipidemia among Saudi adults is warranted, especially among those most at risk. Scientific inquiry into the molecular causes of these manifestations should be pursued as a first step in the discovery of etiologic therapies.

  8. The Relationship Between Child Mortality Rates and Prevalence of Celiac Disease.

    Science.gov (United States)

    Biagi, Federico; Raiteri, Alberto; Schiepatti, Annalisa; Klersy, Catherine; Corazza, Gino R

    2018-02-01

    Some evidence suggests that prevalence of celiac disease in the general population is increasing over time. Because the prognosis of celiac disease was a dismal one before discovering the role of gluten, our aim was to investigate a possible relationship between children under-5 mortality rates and prevalence rates of celiac disease. Thanks to a literature review, we found 27 studies performed in 17 different countries describing the prevalence of celiac disease in schoolchildren; between 1995 and 2011, 4 studies were performed in Italy. A meta-analysis of prevalence rates was performed. Prevalence was compared between specific country under-5 mortality groups, publication year, and age. In the last decades, under-5 mortality rates have been decreasing all over the world. This reduction is paralleled by an increase of the prevalence of celiac disease. The Spearman correlation coefficient was -63%, 95% confidence interval -82% to -33% (P celiac disease in the general population. In the near future, the number of patients with celiac disease will increase, thanks to the better environmental conditions that nowadays allow a better survival of children with celiac disease.

  9. The prevalence of insomnia in the general population in China: A meta-analysis.

    Directory of Open Access Journals (Sweden)

    Xiao-Lan Cao

    Full Text Available This is the first meta-analysis of the pooled prevalence of insomnia in the general population of China. A systematic literature search was conducted via the following databases: PubMed, PsycINFO, EMBASE and Chinese databases (China National Knowledge Interne (CNKI, WanFang Data and SinoMed. Statistical analyses were performed using the Comprehensive Meta-Analysis program. A total of 17 studies with 115,988 participants met the inclusion criteria for the analysis. The pooled prevalence of insomnia in China was 15.0% (95% Confidence interval [CI]: 12.1%-18.5%. No significant difference was found in the prevalence between genders or across time period. The pooled prevalence of insomnia in population with a mean age of 43.7 years and older (11.6%; 95% CI: 7.5%-17.6% was significantly lower than in those with a mean age younger than 43.7 years (20.4%; 95% CI: 14.2%-28.2%. The prevalence of insomnia was significantly affected by the type of assessment tools (Q = 14.1, P = 0.001. The general population prevalence of insomnia in China is lower than those reported in Western countries but similar to those in Asian countries. Younger Chinese adults appear to suffer from more insomnia than older adults.CRD 42016043620.

  10. Prevalence of depressive symptoms among medical students taught using problem-based learning versus traditional methods.

    Science.gov (United States)

    Aragão, José Aderval; Freire, Marianna Ribeiro de Menezes; Nolasco Farias, Lucas Guimarães; Diniz, Sarah Santana; Sant'anna Aragão, Felipe Matheus; Sant'anna Aragão, Iapunira Catarina; Lima, Tarcisio Brandão; Reis, Francisco Prado

    2018-06-01

    To compare depressive symptoms among medical students taught using problem-based learning (PBL) and the traditional method. Beck's Depression Inventory was applied to 215 medical students. The prevalence of depression was calculated as the number of individuals with depression divided by the total number in the sample from each course, with 95% confidence intervals. The statistical significance level used was 5% (p ≤ .05). Among the 215 students, 52.1% were male and 47.9% were female; and 51.6% were being taught using PBL methodology and 48.4% using traditional methods. The prevalence of depression was 29.73% with PBL and 22.12% with traditional methods. There was higher prevalence among females: 32.8% with PBL and 23.1% with traditional methods. The prevalence of depression with PBL among students up to 21 years of age was 29.4% and among those over 21 years, 32.1%. With traditional methods among students up to 21 years of age, it was 16.7%%, and among those over 21 years, 30.1%. The prevalence of depression with PBL was highest among students in the second semester and with traditional methods, in the eighth. Depressive symptoms were highly prevalent among students taught both with PBL and with traditional methods.

  11. Binge eating prevalence according to obesity degrees and associated factors in women

    Directory of Open Access Journals (Sweden)

    Paulla Guimarães Melo

    2015-06-01

    Full Text Available Objective Investigate binge eating (BE prevalence in women according to the obesity degree and assess the associated factors. Methods Cross-sectional study with female adults presenting body mass index (BMI ≥ 35 kg/m2. The analyzed variables were: sociodemographics, health status, obesity history, lifestyle, eating behavior and obesity degree. In order to analyse BE it was used the Binge Eating Scale (BES, which is considered positive when BES ≥ 18 points. Prevalence and prevalence ratios (PR were calculated with confidence intervals (CI of 95%. Multivariate analysis was carried out using Poisson regression. Results BE prevalence was 53.2%, and the prevalence in super superobese women (BMI ≥ 60 kg/m2 was 75%. After multivariate analysis, associations were observed between the age group 40-49 years old (PR = 2.0; 95% CI = 1.2-3.4 and the “snacking habit” (PR = 1.9; 95% CI = 1.2-2.9. Conclusion The prevalence of BE in severe obese women was high. Association with the “snacking habit” can be a BE marker that should be monitored in the severely obese individuals that fit this profile.

  12. Prevalence and profile of musculoskeletal injuries in ballet dancers: A systematic review and meta-analysis.

    Science.gov (United States)

    Smith, Toby O; Davies, Leigh; de Medici, Akbar; Hakim, Allan; Haddad, Fares; Macgregor, Alex

    2016-05-01

    To determine the prevalence of musculoskeletal disorders and anatomical regions which are most frequently injured in ballet dancers. Published (AMED, CiNAHL, EMBASE, SPORTDiscus, psycINFO, MEDLINE, the Cochrane Library) and grey literature databases (OpenGrey, the WHO International Clinical Trials Registry Platform, Current Controlled Trials and the UK National Research Register Archive) were searched from their inception to 25th May 2015 for papers presenting data on injury prevalence in ballet dancers. Two reviewers independently identified all eligible papers, data extracted and critically appraised studies. Study appraisal was conducted using the CASP appraisal tool. Pooled prevalence data with 95% confidence intervals were estimated to determine period prevalence of musculoskeletal disorders and anatomical regions affected. Nineteen studies were eligible, reporting 7332 injuries in 2617 ballet dancers. The evidence was moderate in quality. Period prevalence of musculoskeletal injury was 280% (95% CI: 217-343%). The most prevalent musculoskeletal disorders included: hamstring strain (51%), ankle tendinopathy (19%) and generalized low back pain (14%). No papers explored musculoskeletal disorders in retired ballet dancers. Whilst we have identified which regions and what musculoskeletal disorders are commonly seen ballet dancers. The long-term injury impact of musculoskeletal disorders in retired ballet dancers remains unknown. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The prevalence of Behçet's disease in a city in Central Anatolia in Turkey.

    Science.gov (United States)

    Çölgeçen, Emine; Özyurt, Kemal; Ferahbaş, Ayten; Borlu, Murat; Kulluk, Pınar; Öztürk, Ahmet; Öner, Ayşe Öztürk; Gün, İskender; Aşçıoğlu, Özcan

    2015-03-01

    The prevalence of Behçet's disease (BD) is much higher in countries along the ancient Silk Route, extending from Japan to Mediterranean countries including Turkey, than in northern Europe and the USA. The present study aimed to investigate the prevalence of BD in Kayseri, a city in Central Anatolia in Turkey. This study investigated cross-sectional prevalences of BD in individuals aged >10 years in Kayseri, Turkey, in two stages. The first stage aimed to identify individuals with recurrent oral ulcers (ROUs) through home visits, and the second stage aimed to further examine those with ROUs for the presence of other BD-related manifestations under hospital conditions. The study was conducted using the criteria defined by the International Study Group for Behçet's Disease. The sample size was determined to be 4697 with an expected sampling error of 5.5 per 10,000, with a 95% confidence interval. A standard questionnaire was administered to a total of 5218 individuals. A history of ROU was recorded in 470 (9.0%) of the 5218 residents, and a previous diagnosis of BD was recorded in nine individuals. The prevalence rate of BD was estimated as 17 cases per 10,000 population in Kayseri, Turkey. The present study contributes towards estimations of prevalences of BD in Turkey and towards raising public awareness about the disease. It also supports previous studies that have reported the world's highest prevalences of BD in Turkey. © 2014 The International Society of Dermatology.

  14. 7 CFR 97.18 - Applications handled in confidence.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Applications handled in confidence. 97.18 Section 97.18 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING... confidence. (a) Pending applications shall be handled in confidence. Except as provided below, no information...

  15. 78 FR 56621 - Draft Waste Confidence Generic Environmental Impact Statement

    Science.gov (United States)

    2013-09-13

    ...-2012-0246] RIN 3150-AJ20 Draft Waste Confidence Generic Environmental Impact Statement AGENCY: Nuclear... generic environmental impact statement (DGEIS), NUREG-2157, ``Waste Confidence Generic Environmental... licensed life for operation and prior to ultimate disposal (proposed Waste Confidence rule). The NRC staff...

  16. 21 CFR 26.37 - Confidence building activities.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Confidence building activities. 26.37 Section 26... COMMUNITY Specific Sector Provisions for Medical Devices § 26.37 Confidence building activities. (a) At the beginning of the transitional period, the Joint Sectoral Group will establish a joint confidence building...

  17. 37 CFR 1.14 - Patent applications preserved in confidence.

    Science.gov (United States)

    2010-07-01

    ... in confidence. 1.14 Section 1.14 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND... Records and Files of the Patent and Trademark Office § 1.14 Patent applications preserved in confidence... published under 35 U.S.C. 122(b) are generally preserved in confidence pursuant to 35 U.S.C. 122(a...

  18. Opinion formation with time-varying bounded confidence.

    Science.gov (United States)

    Zhang, YunHong; Liu, QiPeng; Zhang, SiYing

    2017-01-01

    When individuals in social groups communicate with one another and are under the influence of neighbors' opinions, they typically revise their own opinions to adapt to such peer opinions. The individual threshold of bounded confidence will thus be affected by both a change in individual confidence and by neighbor influence. Individuals thus update their own opinions with new bounded confidence, while their updated opinions also influence their neighbors' opinions. Based on this reasoned factual assumption, we propose an opinion dynamics model with time-varying bounded confidence. A directed network is formed by the rule of the individual bounded confidence threshold. The threshold of individual bounded confidence involves both confidence variation and the in/out degree of the individual node. When the confidence variation is greater, an individual's confidence in persisting in his own opinion in interactions is weaker, and the individual is more likely to adopt neighbors' opinions. In networks, the in/out degree is determined by individual neighbors. Our main research involves the process of opinion evolution and the basic laws of opinion cluster formation. Group opinions converge exponentially to consensus with stable neighbors. An individual opinion evolution is determined by the average neighbor opinion effect strength. We also explore the conditions involved in forming a stable neighbor relationship and the influence of the confidence variation in the convergence of the threshold of bounded confidence. The results show that the influence on opinion evolution is greater with increased confidence variation.

  19. Contrasting Academic Behavioural Confidence in Mexican and European Psychology Students

    Science.gov (United States)

    Ochoa, Alma Rosa Aguila; Sander, Paul

    2012-01-01

    Introduction: Research with the Academic Behavioural Confidence scale using European students has shown that students have high levels of confidence in their academic abilities. It is generally accepted that people in more collectivist cultures have more realistic confidence levels in contrast to the overconfidence seen in individualistic European…

  20. Point prevalence of surgical checklist use in Europe

    DEFF Research Database (Denmark)

    Jammer, I; Ahmad, T; Aldecoa, C

    2015-01-01

    BACKGROUND: The prevalence of use of the World Health Organization surgical checklist is unknown. The clinical effectiveness of this intervention in improving postoperative outcomes is debated. METHODS: We undertook a retrospective analysis of data describing surgical checklist use from a 7 day...... models were constructed to explore the relationship between surgical checklist use and hospital mortality. Findings are presented as crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A total of 45 591 patients from 426 hospitals were included in the analysis. A surgical...... checklist was used in 67.5% patients, with marked variation across countries (0-99.6% of patients). Surgical checklist exposure was associated with lower crude hospital mortality (OR 0.84, CI 0.75-0.94; P=0.002). This effect remained after adjustment for baseline risk factors in a multivariate model...

  1. Diverticulosis and the risk of interval colorectal cancer.

    Science.gov (United States)

    Cooper, Gregory S; Xu, Fang; Schluchter, Mark D; Koroukian, Siran M; Barnholtz Sloan, Jill S

    2014-11-01

    Diverticulosis, a prevalent condition at screening colonoscopy, has been associated with colorectal cancers that develop after a clearing colonoscopy, or interval cancers. To quantify the overall risk of diverticulosis in the development of interval cancers and examine this association in relevant subgroups. Using a linked database containing SEER tumor registry data and Medicare claims, we identified patients aged ≥69 years with colorectal cancer who underwent colonoscopy within 6 months of diagnosis. Patients with an additional colonoscopy from 36 to 6 months prior to cancer diagnosis were characterized as having interval cancers. We compared characteristics of patients with interval cancers and detected cancers according to a diagnosis of diverticulosis not associated with a colonoscopy procedure from 1991 through the date of the most recent colonoscopy in both univariate and multivariate models. A previous diagnosis of diverticulosis was documented in 14,452 (26.9 %) patients with detected cancers compared to 2,905 (69.3 %) patients with interval cancers (p diverticulosis diagnoses were without complications such as hemorrhage or diverticulitis. Diverticulosis was strongly associated with interval colorectal cancers in all segments of the colon. Given its known predominance in the left colon, the findings argue against impaired visualization of lesions at colonoscopy as the only pathogenic factor.

  2. Confidence building: what gives confidence to the various categories of stake holders?

    International Nuclear Information System (INIS)

    During the fuelling of the first Olkiluoto Nuclear Power Plant Unit, discussions about sending spent fuel abroad for reprocessing were very topical and the people of Eurajoki got the impression that spent fuel will not be finally disposed of at Eurajoki. This principle was even written down in the long term strategy documents of Eurajoki and it remained there even for a long time after the government of Finland in 1983 had requested TVO to prepare a time schedule and plans for the final disposal of spent fuel in Finland. It did state that the municipality shall act so that high-active spent fuel will not be disposed of in the Eurajoki area. While TVO accordingly investigated the national solution for final disposal, spent nuclear fuel from the Loviisa nuclear power plant was still returned to Soviet Union. This inspired to a certain extent lack of confidence within the inhabitants of Eurajoki and quite many of them had the feeling that TVO had broken its promise. So this topic has been discussed at Eurajoki generally and in the municipal council especially both in connection with final disposal plans and also in connection with operating licence renewals, power upgrade procedures and Decision in Principle Applications during almost 20 years. Good for confidence building is that the information policy of the utility has been very open, which has also been requested by the safety authority STUK. All incidents in the plants have been reported without delay to authorities and also given to publicity even when not safety related. While operating results of both Olkiluoto units have been of internationally top class this has contributed to the formation of confidence. Routines for dialogue between municipality and utilities have been created in order to guarantee continuity. Thus several types of liaison groups were formed. (author)

  3. Cross‐cultural adaptation and validation of the Karitane Parenting Confidence Scale of maternal confidence assessment for use in Brazil

    Directory of Open Access Journals (Sweden)

    Lívia W. Pereira

    2018-03-01

    Conclusion: The transcultural adaptation and validation of the confidence maternal questionnaire into Brazilian Portuguese language and culture showed good reliability for this sample. The results of its use demonstrated that maternal confidence was associated with schooling, age and parity.

  4. Parents' obesity-related behavior and confidence to support behavioral change in their obese child: data from the STAR study.

    Science.gov (United States)

    Arsenault, Lisa N; Xu, Kathleen; Taveras, Elsie M; Hacker, Karen A

    2014-01-01

    Successful childhood obesity interventions frequently focus on behavioral modification and involve parents or family members. Parental confidence in supporting behavior change may be an element of successful family-based prevention efforts. We aimed to determine whether parents' own obesity-related behaviors were related to their confidence in supporting their child's achievement of obesity-related behavioral goals. Cross-sectional analyses of data collected at baseline of a randomized control trial testing a treatment intervention for obese children (n = 787) in primary care settings (n = 14). Five obesity-related behaviors (physical activity, screen time, sugar-sweetened beverage, sleep duration, fast food) were self-reported by parents for themselves and their child. Behaviors were dichotomized on the basis of achievement of behavioral goals. Five confidence questions asked how confident the parent was in helping their child achieve each goal. Logistic regression modeling high confidence was conducted with goal achievement and demographics as independent variables. Parents achieving physical activity or sleep duration goals were significantly more likely to be highly confident in supporting their child's achievement of those goals (physical activity, odds ratio 1.76; 95% confidence interval 1.19-2.60; sleep, odds ratio 1.74; 95% confidence interval 1.09-2.79) independent of sociodemographic variables and child's current behavior. Parental achievements of TV watching and fast food goals were also associated with confidence, but significance was attenuated after child's behavior was included in models. Parents' own obesity-related behaviors are factors that may affect their confidence to support their child's behavior change. Providers seeking to prevent childhood obesity should address parent/family behaviors as part of their obesity prevention strategies. Copyright © 2014 Academic Pediatric Association. Published by Elsevier Inc. All rights reserved.

  5. Some Characterizations of Convex Interval Games

    NARCIS (Netherlands)

    Brânzei, R.; Tijs, S.H.; Alparslan-Gok, S.Z.

    2008-01-01

    This paper focuses on new characterizations of convex interval games using the notions of exactness and superadditivity. We also relate big boss interval games with concave interval games and obtain characterizations of big boss interval games in terms of exactness and subadditivity.

  6. Combination of interval set and soft set

    Directory of Open Access Journals (Sweden)

    Keyun Qin

    2013-04-01

    Full Text Available Soft set theory and interval set theory are all mathematical tools for dealing with uncertainties. This paper is devoted to the discussion of soft interval set and its application. The notion of soft interval sets is introduced by combining soft set and interval set. Several operations on soft interval sets are presented in a manner parallel to that used in defining operations on soft sets and the lattice structures of soft interval sets are established. In addition, a soft interval set based decision making problem is analyzed.

  7. Feature Augmentation for Learning Confidence Measure in Stereo Matching.

    Science.gov (United States)

    Kim, Sunok; Min, Dongbo; Kim, Seungryong; Sohn, Kwanghoon

    2017-09-08

    Confidence estimation is essential for refining stereo matching results through a post-processing step. This problem has recently been studied using a learning-based approach, which demonstrates a substantial improvement on conventional simple non-learning based methods. However, the formulation of learning-based methods that individually estimates the confidence of each pixel disregards spatial coherency that might exist in the confidence map, thus providing a limited performance under challenging conditions. Our key observation is that the confidence features and resulting confidence maps are smoothly varying in the spatial domain, and highly correlated within the local regions of an image. We present a new approach that imposes spatial consistency on the confidence estimation. Specifically, a set of robust confidence features is extracted from each superpixel decomposed using the Gaussian mixture model (GMM), and then these features are concatenated with pixel-level confidence features. The features are then enhanced through adaptive filtering in the feature domain. In addition, the resulting confidence map, estimated using the confidence features with a random regression forest, is further improved through K-nearest neighbor (K-NN) based aggregation scheme on both pixel-and superpixel-level. To validate the proposed confidence estimation scheme, we employ cost modulation or ground control points (GCPs) based optimization in stereo matching. Experimental results demonstrate that the proposed method outperforms state-of-the-art approaches on various benchmarks including challenging outdoor scenes.

  8. Individual consistency in the accuracy and distribution of confidence judgments.

    Science.gov (United States)

    Ais, Joaquín; Zylberberg, Ariel; Barttfeld, Pablo; Sigman, Mariano

    2016-01-01

    We examine which aspects of the confidence distributions - its shape, its bias toward higher or lower values, and its ability to distinguish correct from erred trials - are idiosyncratic of the who (individual specificity), the when (variability across days) and the what (task specificity). Measuring confidence across different sessions of four different perceptual tasks we show that: (1) Confidence distributions are virtually identical when measured in different days for the same subject and the same task, constituting a subjective fingerprint, (2) The capacity of confidence reports to distinguish correct from incorrect responses is only modestly (but significantly) correlated when compared across tasks, (3) Confidence distributions are very similar for tasks that involve different sensory modalities but have similar structure, (4) Confidence accuracy is independent of the mean and width of the confidence distribution, (5) The mean of the confidence distribution (an individual's confidence bias) constitutes the most efficient indicator to infer a subject's identity from confidence reports and (6) Confidence bias measured in simple perceptual decisions correlates with an individual's optimism bias measured with standard questionnaire. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Effects of confidence and anxiety on flow state in competition.

    Science.gov (United States)

    Koehn, Stefan

    2013-01-01

    Confidence and anxiety are important variables that underlie the experience of flow in sport. Specifically, research has indicated that confidence displays a positive relationship and anxiety a negative relationship with flow. The aim of this study was to assess potential direct and indirect effects of confidence and anxiety dimensions on flow state in tennis competition. A sample of 59 junior tennis players completed measures of Competitive State Anxiety Inventory-2d and Flow State Scale-2. Following predictive analysis, results showed significant positive correlations between confidence (intensity and direction) and anxiety symptoms (only directional perceptions) with flow state. Standard multiple regression analysis indicated confidence as the only significant predictor of flow. The results confirmed a protective function of confidence against debilitating anxiety interpretations, but there were no significant interaction effects between confidence and anxiety on flow state.

  10. Geographical variation in the prevalence of positive skin tests to environmental aeroallergens in the European Community Respiratory Health Survey I.

    Science.gov (United States)

    Bousquet, P-J; Chinn, S; Janson, C; Kogevinas, M; Burney, P; Jarvis, D

    2007-03-01

    Many studies have reported the prevalence of sensitization using skin prick tests. However, comparisons between studies and between regions are difficult because the number and the type of allergens tested vary widely. Using the European Community Health Respiratory Survey I data, the geographical variation of sensitization to environmental allergen as measured by skin tests was established. Adults aged 20-44 years, living in 35 centres in 15 developed countries, underwent skin tests for allergy to nine common aeroallergens: Dermatophagoides pteronyssinus, timothy grass, cat, Cladosporium herbarium, Alternaria alternata, birch, Olea europea, common ragweed and Parietaria judaica. The age-sex standardized prevalence of sensitization was determined and centres with high (95% confidence interval above and excluding study median) and low prevalence (95% confidence interval below and excluding study median) of sensitization to each allergen and to any of the nine allergens were identified. There was substantial geographical variation in the prevalence of sensitization to each of the nine allergens tested and in the prevalence of sensitization to any allergen (lowest 17.1%, median 36.8% and highest 54.8%). Sensitization to D. pteronyssinus, grass pollen and cat were usually the most prevalent (median between centre 21.7%, 16.9% and 8.8%, respectively). Timothy grass sensitization was higher than that for any other pollen species. As expected, geographical variations of sensitization to environmental allergen were observed across centres. These findings were compatible for those observed with serum-specific IgE. Skin tests can be used to assess the geographical distribution of allergens in a multicentric epidemiological survey.

  11. Metabolic syndrome in Spain: prevalence and coronary risk associated with harmonized definition and WHO proposal. DARIOS study.

    Science.gov (United States)

    Fernández-Bergés, Daniel; Cabrera de León, Antonio; Sanz, Héctor; Elosua, Roberto; Guembe, María J; Alzamora, Maite; Vega-Alonso, Tomás; Félix-Redondo, Francisco J; Ortiz-Marrón, Honorato; Rigo, Fernando; Lama, Carmen; Gavrila, Diana; Segura-Fragoso, Antonio; Lozano, Luis; Marrugat, Jaume

    2012-03-01

    To update the prevalence of metabolic syndrome and associated coronary risk in Spain, using the harmonized definition and the new World Health Organization proposal (metabolic premorbid syndrome), which excludes diabetes mellitus and cardiovascular disease. Individual data pooled analysis study of 24,670 individuals from 10 autonomous communities aged 35 to 74 years. Coronary risk was estimated using the REGICOR function. Prevalence of metabolic syndrome was 31% (women 29% [95% confidence interval, 25%-33%], men 32% [95% confidence interval, 29%-35%]). High blood glucose (P=.019) and triglycerides (Pmetabolic syndrome, but abdominal obesity (Pmetabolic syndrome showed moderate coronary risk (8% men, 5% women), although values were higher (Psyndrome (4% men, 2% women). Women and men with metabolic syndrome had 2.5 and 2 times higher levels of coronary risk, respectively (Pmetabolic premorbid syndrome was 24% and the increase in coronary risk was also proportionately larger in women than in men (2 vs 1.5, respectively; Pmetabolic syndrome is 31%; metabolic premorbid syndrome lowers this prevalence to 24% and delimits the population for primary prevention. The increase in coronary risk is proportionally larger in women, in both metabolic syndrome and metabolic premorbid syndrome. Copyright © 2011 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  12. The Prevalence of Sexual Revictimization: A Meta-Analytic Review.

    Science.gov (United States)

    Walker, Hannah E; Freud, Jennifer S; Ellis, Robyn A; Fraine, Shawn M; Wilson, Laura C

    2017-01-01

    The literature consistently demonstrates evidence that child sexual abuse survivors are at greater risk of victimization later in life than the general population. This phenomenon is called sexual revictimization. Although this finding is robust, there is a large amount of variability in the prevalence rates of revictimization demonstrated in the literature. The purpose of the present meta-analysis was to calculate an average prevalence rate of revictimization across the literature and to examine moderators that may potentially account for the observed variability. Based on a review of PsycINFO and PILOTS, 1,412 articles were identified and reviewed for inclusion. This process resulted in the inclusion of 80 studies, which contained 12,252 survivors of child sexual abuse. The mean prevalence of sexual revictimization across studies was 47.9% (95% confidence intervals [43.6%, 52.3%]), suggesting that almost half of child sexual abuse survivors are sexually victimized in the future. The present study failed to find support for any of the examined moderators. Potential explanations of and implications for the results are offered, including suggestions for therapists.

  13. Prevalence and risk factors of asymptomatic colorectal diverticulosis in Taiwan.

    Science.gov (United States)

    Wang, Fu-Wei; Chuang, Hung-Yi; Tu, Ming-Shium; King, Tai-Ming; Wang, Jui-Ho; Hsu, Chao-Wen; Hsu, Ping-I; Chen, Wen-Chi

    2015-04-01

    To investigate the prevalence and risk factors of asymptomatic colorectal diverticulosis in Taiwanese general population. From January 2009 to December 2011, consecutive asymptomatic subjects undergoing a health check-up were evaluated by colonoscopy. The colorectal diverticulosis was assessed, and a medical history and demographic data were obtained from each subject. Logistic regression analysis was conducted to search the risk factors of colorectal diverticulosis. Of the 1899 asymptomatic subjects, the prevalence of colorectal diverticulosis was 13.5%. On univariate logistic regression analysis, age over 60 years old, male, adenomatous polyp, current smoking and heavy alcohol consumption were significantly associated with diverticulosis. Multivariate logistic regression analysis revealed that age over 60 years old (relative risk [RR], 2.57; 95% confidence interval [CI], 1.64-6.47), adenomatous polyps (RR, 2.18; 95% CI, 1.18-4.61) and heavy alcohol consumption (RR, 1.82; 95% CI, 1.04-3.08) were independent predictors for colorectal diverticulosis. The prevalence of asymptomatic colorectal diverticulosis was 13.5% in Taiwan. Age over 60 years old, adenomatous polyp and heavy alcohol consumption may affect the risk of development of the disease.

  14. Restless legs syndrome in migraine patients: prevalence and severity.

    Science.gov (United States)

    van Oosterhout, W P J; van Someren, E J W; Louter, M A; Schoonman, G G; Lammers, G J; Rijsman, R M; Ferrari, M D; Terwindt, G M

    2016-06-01

    Our aim was to study not only the prevalence but more importantly the severity and the correlation between sleep quality and restless legs syndrome (RLS) in a large population of well-defined migraine patients as poor sleep presumably triggers migraine attacks. In a large cross-sectional and observational study, data on migraine and RLS were collected from 2385 migraine patients (according to the International Classification of Headache Disorders ICHD-IIIb) and 332 non-headache controls. RLS severity (International RLS Study Group severity scale) and sleep quality (Pittsburgh Sleep Quality Index) were assessed. Risk factors for RLS and RLS severity were calculated using multivariable-adjusted regression models. Restless legs syndrome prevalence in migraine was higher than in controls (16.9% vs. 8.7%; multivariable-adjusted odds ratio 1.83; 95% confidence interval 1.18-2.86; P = 0.008) and more severe (adjusted severity score 14.5 ± 0.5 vs. 12.0 ± 1.1; P = 0.036). Poor sleepers were overrepresented amongst migraineurs (50.1% vs. 25.6%; P Restless legs syndrome is not only twice as prevalent but also more severe in migraine patients, and associated with decreased sleep quality. © 2016 EAN.

  15. [Prevalence and associated factors of macrosomia in Peru, 2013].

    Science.gov (United States)

    Cunha, Antonio José Ledo Alves da; Toro, Manuel Sobrino; Gutiérrez, César; Alarcón-Villaverde, Jorge

    2017-01-01

    To determine the prevalence of macrosomia and factors associated with it in Peru and to describe the occurrence of complications peri- and postpartum. Birth weights of children under the age of 5 years were analyzed using data from the 2013 Demographic and Family Health Survey (ENDES) carried out by the Instituto Nacional de Estadística e Informática. Children with a birth weight higher than 4000 g were considered macrosomic. A logistic regression analysis was used to establish the independent association of sociodemographic factors with macrosomia. The sample comprised 6121 children. The prevalence of macrosomia was 5.3% (95% interval confidence: 4.8-5.9%). Being male, a higher birth order, maternal obesity, and greater maternal height were independently linked with macrosomia. Caesarean births were more common in macrosomic children than unaffected ones (43.9% vs 26.9%). Complications during birth and postpartum were common but not statistically linked with macrosomia. The prevalence of macrosomia in Peru is relatively low compared to other low-to-middle income countries. The factors associated with macrosomia were mainly unmodifiable, with the exception of maternal obesity. Macrosomic children were more frequently born by caesarean. Weight reduction and the prevention of obesity in women of childbearing age in Peru could potentially reduce macrosomia and caesarean rates.

  16. Prevalence of intravenous medication administration errors: a cross-sectional study.

    Science.gov (United States)

    Fekadu, Tezeta; Teweldemedhin, Mebrahtu; Esrael, Eyerusalem; Asgedom, Solomon Weldegebreal

    2017-01-01

    Intravenous medication administration errors (MAEs) may be accompanied by avoidable undesirable effects, which might result in clinical complications. The aim of the study was to determine the prevalence of MAEs and to identify the factors associated with such errors. A hospital-based cross-sectional study was conducted from March to April 2015. Data were collected by direct observation using a pretested data collection tool. Simple random sampling was used, and bivariate logistic regression model was used to identify the factors associated with MAEs. P value <0.05 was considered statistically significant. A total of 134 patients were found to be eligible for the study. More than half of the study participants were males (76 [56.7%]). The rate of MAE was 46.1%, with the missed dose (n=162, 95.8%) being reported as the most common error. The age groups of 60-79 years (adjusted odds ratio = 2.166, confidence interval = 1.532-8.799) and 80-101 years (adjusted odds ratio = 1.52, confidence interval = 1.198-5.584) were the determinants of MAEs. A high prevalence of MAEs was found. Enhancing the knowledge and practical skills of clinical nurses might minimize such errors.

  17. Postmortem changes mistaken for traumatic lesions: a highly prevalent reason for coroner's autopsy request.

    Science.gov (United States)

    Sauvageau, Anny; Racette, Stéphanie

    2008-06-01

    Postmortem changes are well known for their possible misinterpretation as traumatic lesions which can mislead to suspicion of violent death and therefore to a forensic autopsy request. As far as we know, a systematic review of the prevalence of such a reason for coroner's autopsy request has not been done yet. A retrospective study of 230 forensic autopsies requested by the Coroner's office from 2002 to 2004 in the province of Quebec, Canada, was conducted by the authors. Of the 230 reviewed cases, postmortem artifacts mistaken for traumatic lesions were found in 18 cases. These misinterpretation were based on 5 categories of portmortem changes: purge fluid drainage in 12 cases (66.7%), bluish discoloration by lividity in 5 cases (27.8%), parchment-like drying of the skin in 4 cases (22.2%), bloating from gas formation in 4 cases (22.2%), and skin slippage in 1 case (5.56%). Therefore, postmortem artifacts misinterpretation occurred in 7.83% (95% confidence interval 0.05-0.12) of all requested forensic autopsies and in 35.29% (95% confidence interval 0.23-0.50) of decomposed autopsy cases. This study clearly establishes the high prevalence of postmortem artifacts as main reason for forensic autopsy request. Hence, in a context of forensic pathologist shortage, the improvement of coroner continuous training may reduce the workload.

  18. Urinary incontinence in bitches under primary veterinary care in England: prevalence and risk factors.

    Science.gov (United States)

    O'Neill, D G; Riddell, A; Church, D B; Owen, L; Brodbelt, D C; Hall, J L

    2017-12-01

    To estimate prevalence and demographic risk factors for urinary incontinence in bitches under primary veterinary care in England. The study population included all bitches within the VetCompass database from September 1, 2009 to July 7, 2013. Electronic patient records were searched for urinary incontinence cases and additional demographic and clinical information was extracted. Of 100,397 bitches attending 119 clinics in England, an estimated 3108 were diagnosed with urinary incontinence. The prevalence of urinary incontinence was 3·14% (95% confidence intervals: 2·97 to 3·33). Medical therapy was prescribed to 45·6% cases. Predisposed breeds included the Irish setter (odds ratio: 8·09; 95% confidence intervals: 3·15 to 20·80; Prisk breeds including the Irish setter, Dobermann, bearded collie, rough collie and Dalmatian. These results provide an evidence base for clinicians to enhance clinical recommendations on neutering and weight control, especially in high-risk breeds. © 2017 British Small Animal Veterinary Association.

  19. Prevalence and predictors of anxiety and depression among esophageal cancer patients prior to surgery.

    Science.gov (United States)

    Hellstadius, Y; Lagergren, J; Zylstra, J; Gossage, J; Davies, A; Hultman, C M; Lagergren, P; Wikman, A

    2016-11-01

    This study aims to establish the prevalence and predictors of anxiety and depression among esophageal cancer patients, post-diagnosis but prior to curatively intended surgery. This was a cross-sectional study using data from a hospital-based prospective cohort study, carried out at St Thomas' Hospital, London. Potential predictor variables were retrieved from medical charts and self-report questionnaires. Anxiety and depression were measured prior to esophageal cancer surgery, using the Hospital Anxiety and Depression Scale. Prevalence of anxiety and depression was calculated using the established cutoff (scores ≥8 on each subscale) indicating cases of 'possible-probable' anxiety or depression, and multivariable logistic regression analyses were performed to examine predictors of emotional distress. Among the 106 included patients, 36 (34%) scored above the cutoff (≥8) for anxiety and 24 (23%) for depression. Women were more likely to report anxiety than men (odds ratio 4.04, 95% confidence interval 1.45-11.16), and patients reporting limitations in their activity status had more than five times greater odds of reporting depression (odds ratio 6.07, 95% confidence interval 1.53-24.10). A substantial proportion of esophageal cancer patients report anxiety and/or depression prior to surgery, particularly women and those with limited activity status, which highlights a need for qualified emotional support. © 2015 International Society for Diseases of the Esophagus.

  20. Prevalence of Cleft Lip/Palate in the Fangshan District of Beijing, 2006-2012.

    Science.gov (United States)

    Yang, Yanfen; Liu, Hui; Ma, Ruixin; Jin, Lei

    2018-01-01

    To estimate the cleft lip with or without cleft palate (CL/P) prevalence among births between 2006 and 2012 in Fangshan district of Beijing, China. Surveillance data analysis. All hospitals that provide obstetric services in the district. The CL/P cases presented for this report were from 13 weeks' gestation to 7 days postpartum. The CL/P prevalence was defined as the number of cases per 10 000 births, including live births and stillbirths at 28 weeks' gestation or beyond. The overall CL/P prevalence was 18.9 (95% confidence interval [CI]: 15.1-22.7) per 10 000 births. From 2006 to 2012, the CL/P prevalence was 19.3, 20.2, 10.9, 16.1, 17.5, 25.4, and 22.3 per 10 000 births; annually, no significant change was noted ( P for trend = .311). The prevalence of cleft palate, cleft lip, and cleft lip and palate were 3.4 (95% CI: 2.0-5.4), 6.2 (95% CI: 4.2-8.8), and 9.4 (95% CI: 6.9-12.4) per 10 000 births, respectively. The CL/P prevalence among the nonpermanent residents (31.4 per 10 000 births) was 2.31 times that of permanent residents (13.6 per 10 000 births). Among nonpermanent residents, the CL/P prevalence showed an upward trend over the study period ( P for trend = .036), that increased from 38.8 (95% CI: 16.5-76.6) per 10 000 births in 2006 to 54.6 (95% CI: 25.7-100.4) per 10 000 births in 2012. The overall CL/P prevalence was stable in the Fangshan district. However, the CL/P prevalence of the nonpermanent residents increased significantly.

  1. Epidemiology of tuberculosis in a high HIV prevalence population provided with enhanced diagnosis of symptomatic disease.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Corbett

    2007-01-01

    Full Text Available Directly observed treatment short course (DOTS, the global control strategy aimed at controlling tuberculosis (TB transmission through prompt diagnosis of symptomatic smear-positive disease, has failed to prevent rising tuberculosis incidence rates in Africa brought about by the HIV epidemic. However, rising incidence does not necessarily imply failure to control tuberculosis transmission, which is primarily driven by prevalent infectious disease. We investigated the epidemiology of prevalent and incident TB in a high HIV prevalence population provided with enhanced primary health care.Twenty-two businesses in Harare, Zimbabwe, were provided with free smear- and culture-based investigation of TB symptoms through occupational clinics. Anonymised HIV tests were requested from all employees. After 2 y of follow-up for incident TB, a culture-based survey for undiagnosed prevalent TB was conducted. A total of 6,440 of 7,478 eligible employees participated. HIV prevalence was 19%. For HIV-positive and -negative participants, the incidence of culture-positive tuberculosis was 25.3 and 1.3 per 1,000 person-years, respectively (adjusted incidence rate ratio = 18.8; 95% confidence interval [CI] = 10.3 to 34.5: population attributable fraction = 78%, and point prevalence after 2 y was 5.7 and 2.6 per 1,000 population (adjusted odds ratio = 1.7; 95% CI = 0.5 to 6.8: population attributable fraction = 14%. Most patients with prevalent culture-positive TB had subclinical disease when first detected.Strategies based on prompt investigation of TB symptoms, such as DOTS, may be an effective way of controlling prevalent TB in high HIV prevalence populations. This may translate into effective control of TB transmission despite high TB incidence rates and a period of subclinical infectiousness in some patients.

  2. Point Prevalence of Pediatric Inflammatory Bowel Disease in New Zealand in 2015: Initial Results from the PINZ Study.

    Science.gov (United States)

    Lopez, Robert N; Evans, Helen M; Appleton, Laura; Bishop, Jonathan; Chin, Simon; Mouat, Stephen; Gearry, Richard B; Day, Andrew S

    2017-08-01

    The incidence of pediatric inflammatory bowel disease (IBD) around the world is increasing. However, there is a scarcity of data on the epidemiology of pediatric IBD in the Southern Hemisphere. This study aimed to document the point prevalence of pediatric IBD in New Zealand on June 30, 2015. All patients in New Zealand, under 16 years of age, with a diagnosis of IBD on June 30, 2015 were identified. Demographic and disease phenotypic details were collected and entered into a secure database. Age-specific population data for New Zealand were obtained and national and regional prevalence rates were calculated. The point prevalence of pediatric IBD, Crohn's disease, ulcerative colitis, and inflammatory bowel disease unclassified in New Zealand on June 30, 2015 was (95% confidence intervals) 21.7 (18.9-24.8), 16.5 (14.0-19.2), 3.3 (2.2-4.6), and 1.9 (1.2-3.0) per 100,000 children, respectively. There was a striking disparity between the prevalence rates in the North and South Islands. The point prevalence of pediatric IBD in New Zealand represents the first-ever national, population-based prevalence rates of pediatric IBD published. Results from the Paediatric IBD in New Zealand (PINZ) study are also the first to show markedly higher prevalence rates of IBD in the southern part of a country compared with its northern counterpart. Ongoing prospective ascertainment of the incidence of pediatric IBD is required.

  3. Multicenter European Prevalence Study of Neurocognitive Impairment and Associated Factors in HIV Positive Patients

    DEFF Research Database (Denmark)

    Haddow, Lewis J; Laverick, Rosanna; Daskalopoulou, Marina

    2017-01-01

    ≤-1 in at least 2 out of 5 cognitive domains. Participants' mean age was 45.8 years; 84% male; 87% white; 56% university educated; median CD4 count 550 cells/mm(3); 89% on antiretroviral therapy. 156 (35%) participants had NCI, among whom 26 (17%; 5.8% overall) reported a decline in activities...... of daily living. Prevalence of NCI was lower in those always able to afford basic needs (adjusted prevalence ratio [aPR] 0.71, 95% confidence interval [CI] 0.54-0.94) or with a university education (aPR 0.72, 95% CI 0.54-0.97) and higher in those with severe depressive symptoms (aPR 1.53, 95% CI 1...

  4. Prevalence of developmental coordination disorder among mainstream school children in India.

    Science.gov (United States)

    Girish, Srilatha; Raja, Kavitha; Kamath, Asha

    2016-05-31

    To estimate the prevalence of DCD in children between ages of 6-15 years attending mainstream schools in a school district in southern India using criteria of Diagnostic and Statistical Manual of Mental Disorder, Fifth Edition (DSM-5). A total of 2282 children, were screened with Kannada version of DCDQ'07. All the children who were identified as probable. DCD cases were defined by using inclusion (Criteria A, B and C) and exclusion criteria (D) of DSM-5 which are ascertained by specific tests. Nineteen (0.8%) children were identified as DCD with girls (1.1%) affected more than boys (0.5%) at confidence interval of 95%. The prevalence of DCD using DSM-5 criteria is found to be 0.8% in Southern India. Girls were twice affected than boys.

  5. Confidence ellipses: A variation based on parametric bootstrapping applicable on Multiple Factor Analysis results for rapid graphical evaluation

    DEFF Research Database (Denmark)

    Dehlholm, Christian; Brockhoff, Per B.; Bredie, Wender L. P.

    2012-01-01

    results regardless of the origin of data and the nature of the original variables. The approach is suitable for getting an overview of product confidence intervals and also applicable for data obtained from ‘one repetition’ evaluations. Furthermore, it is a convenient way to get an overview of variations...

  6. Chinese Management Research Needs Self-Confidence but not Over-confidence

    DEFF Research Database (Denmark)

    Li, Xin; Ma, Li

    2018-01-01

    Chinese management research aims to contribute to global management knowledge by offering rigorous and innovative theories and practical recommendations both for managing in China and outside. However, two seemingly opposite directions that researchers are taking could prove detrimental...... Chinese management research is recommended. Specifically, it is recommended that researchers can focus on phenomena salient in China and follow rigorous scientific methods, as illustrated by a few exemplary studies using the Chinese context. In this way, Chinese management research can advance...... to the healthy development of Chinese management research. We argue that the two directions share a common ground that lies in the mindset regarding the confidence in the work on and from China. One direction of simply following the American mainstream on academic rigor demonstrates a lack of self...

  7. "Yes, we can!" review on team confidence in sports.

    Science.gov (United States)

    Fransen, Katrien; Mertens, Niels; Feltz, Deborah; Boen, Filip

    2017-08-01

    During the last decade, team confidence has received more and more attention in the sport psychology literature. Research has demonstrated that athletes who are more confident in their team's abilities exert more effort, set more challenging goals, are more resilient when facing adversities, and ultimately perform better. This article reviews the existing literature in order to provide more clarity in terms of the conceptualization and the operationalization of team confidence. We thereby distinguish between collective efficacy (i.e., process-oriented team confidence) and team outcome confidence (i.e., outcome-oriented team confidence). In addition, both the sources as well as the outcomes of team confidence will be discussed. Furthermore, we will go deeper into the dispersion of team confidence and we will evaluate the current guidelines on how to measure both types of team confidence. Building upon this base, the article then highlights interesting avenues for future research in order to further improve both our theoretical knowledge on team confidence and its application to the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Beyond hypercorrection: remembering corrective feedback for low-confidence errors.

    Science.gov (United States)

    Griffiths, Lauren; Higham, Philip A

    2018-02-01

    Correcting errors based on corrective feedback is essential to successful learning. Previous studies have found that corrections to high-confidence errors are better remembered than low-confidence errors (the hypercorrection effect). The aim of this study was to investigate whether corrections to low-confidence errors can also be successfully retained in some cases. Participants completed an initial multiple-choice test consisting of control, trick and easy general-knowledge questions, rated their confidence after answering each question, and then received immediate corrective feedback. After a short delay, they were given a cued-recall test consisting of the same questions. In two experiments, we found high-confidence errors to control questions were better corrected on the second test compared to low-confidence errors - the typical hypercorrection effect. However, low-confidence errors to trick questions were just as likely to be corrected as high-confidence errors. Most surprisingly, we found that memory for the feedback and original responses, not confidence or surprise, were significant predictors of error correction. We conclude that for some types of material, there is an effortful process of elaboration and problem solving prior to making low-confidence errors that facilitates memory of corrective feedback.

  9. Factors affecting midwives' confidence in intrapartum care: a phenomenological study.

    Science.gov (United States)

    Bedwell, Carol; McGowan, Linda; Lavender, Tina

    2015-01-01

    midwives are frequently the lead providers of care for women throughout labour and birth. In order to perform their role effectively and provide women with the choices they require midwives need to be confident in their practice. This study explores factors which may affect midwives' confidence in their practice. hermeneutic phenomenology formed the theoretical basis for the study. Prospective longitudinal data collection was completed using diaries and semi-structured interviews. Twelve midwives providing intrapartum care in a variety of settings were recruited to ensure a variety of experiences in different contexts were captured. the principal factor affecting workplace confidence, both positively and negatively, was the influence of colleagues. Perceived autonomy and a sense of familiarity could also enhance confidence. However, conflict in the workplace was a critical factor in reducing midwives' confidence. Confidence was an important, but fragile, phenomenon to midwives and they used a variety of coping strategies, emotional intelligence and presentation management to maintain it. this is the first study to highlight both the factors influencing midwives' workplace confidence and the strategies midwives employed to maintain their confidence. Confidence is important in maintaining well-being and workplace culture may play a role in explaining the current low morale within the midwifery workforce. This may have implications for women's choices and care. Support, effective leadership and education may help midwives develop and sustain a positive sense of confidence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Disparities in parent confidence managing child weight-related behaviors.

    Science.gov (United States)

    Phan, Thao-Ly T; Curran, Jennifer L; Abatemarco, Diane J

    2015-01-01

    To describe ethnic disparities in parental confidence managing child weight-related behaviors. This was a cross-sectional survey of 59 parents of children with obesity between 4 and 7 years of age presenting to a tertiary care pediatric weight management clinic. Parents completed a validated measure assessing their confidence managing their child's weight-related behaviors (parent confidence score). Student's t-tests and linear regression analyses were used to determine parent and child characteristics associated with parent confidence score. Families were ethnically diverse with half being of Hispanic ethnicity. Mean parent confidence score was 159 (SD 66) with 71% of parents with parent confidence scores below the clinical cut-off for the measure. Parent confidence score was lower among Hispanic (mean 133, SD 67) compared to non-Hispanic parents (mean 184, SD 55, p confidence score was most strongly associated with parental ethnicity (β = -0.39, p = 0.002, adjusted R(2) = 0.14). Parental confidence managing weight-related behaviors was low among parents of young obese children, especially those of Hispanic ethnicity. This study highlights the need to assess parental confidence in managing weight-related behaviors as part of pediatric obesity care and to provide counseling to improve parental management of weight-related behaviors in a culturally-appropriate manner. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Country of birth and other factors associated with hepatitis B prevalence in a population with high levels of immigration.

    Science.gov (United States)

    Reekie, Joanne; Gidding, Heather F; Kaldor, John M; Liu, Bette

    2013-09-01

    While hepatitis B virus (HBV) prevalence is known to vary greatly between countries, systematically collected population-level prevalence data from some countries is limited. Antenatal HBV screening programs in countries with substantial migrant populations provide the opportunity to systematically examine HBV prevalence in order to inform local and regional HBV estimates. A comprehensive register of Australian mothers giving birth from January 2000 to December 2008 was linked to a register of HBV notifications. Age-standardized prevalence of chronic HBV were calculated overall and by the mother's country of birth. Multiple logistic regression was used to investigate other factors associated with HBV prevalence. Five hundred twenty-three thousand six hundred sixty-five women were included and linked to 3861 HBV notifications. The age-standardized HBV prevalence was low (0.75%, 95% confidence interval 0.72-0.79). The highest HBV prevalence rates were observed in women born in Cambodia (8.60%), Taiwan (8.10%), Vietnam (7.49%), China (6.80%), and Tonga (6.51%). Among Australia-born women, those who smoked during pregnancy, were from a more disadvantaged socioeconomic background, and lived in remote areas were more likely to have HBV. There was also a trend suggesting a decrease in the prevalence of HBV over time. Antenatal screening for HBV can provide systematic population estimates of HBV prevalence in migrants and also identify other high prevalence groups. Longer follow-up will be required to confirm the small decrease in HBV prevalence observed in this study. © 2013 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.

  12. Prevalence study of genetically defined skeletal muscle channelopathies in England.

    Science.gov (United States)

    Horga, Alejandro; Raja Rayan, Dipa L; Matthews, Emma; Sud, Richa; Fialho, Doreen; Durran, Siobhan C M; Burge, James A; Portaro, Simona; Davis, Mary B; Haworth, Andrea; Hanna, Michael G

    2013-04-16

    To obtain minimum point prevalence rates for the skeletal muscle channelopathies and to evaluate the frequency distribution of mutations associated with these disorders. Analysis of demographic, clinical, electrophysiologic, and genetic data of all patients assessed at our national specialist channelopathy service. Only patients living in the United Kingdom with a genetically defined diagnosis of nondystrophic myotonia or periodic paralysis were eligible for the study. Prevalence rates were estimated for England, December 2011. A total of 665 patients fulfilled the inclusion criteria, of which 593 were living in England, giving a minimum point prevalence of 1.12/100,000 (95% confidence interval [CI] 1.03-1.21). Disease-specific prevalence figures were as follows: myotonia congenita 0.52/100,000 (95% CI 0.46-0.59), paramyotonia congenita 0.17/100,000 (95% CI 0.13-0.20), sodium channel myotonias 0.06/100,000 (95% CI 0.04-0.08), hyperkalemic periodic paralysis 0.17/100,000 (95% CI 0.13-0.20), hypokalemic periodic paralysis 0.13/100,000 (95% CI 0.10-0.17), and Andersen-Tawil syndrome (ATS) 0.08/100,000 (95% CI 0.05-0.10). In the whole sample (665 patients), 15 out of 104 different CLCN1 mutations accounted for 60% of all patients with myotonia congenita, 11 out of 22 SCN4A mutations for 86% of paramyotonia congenita/sodium channel myotonia pedigrees, and 3 out of 17 KCNJ2 mutations for 42% of ATS pedigrees. We describe for the first time the overall prevalence of genetically defined skeletal muscle channelopathies in England. Despite the large variety of mutations observed in patients with nondystrophic myotonia and ATS, a limited number accounted for a large proportion of cases.

  13. Prevalence rate of chronic overuse pain in taekwondo athletes.

    Science.gov (United States)

    Koh, Jae-Ok

    2017-10-01

    The aim of this study was to estimate the prevalence of chronic overuse pain (COP) and to identify possible risk factors of COP in sport poomsae taekwondo. This is a cross-sectional survey. A total of 263 sport-poomsae competitors (112 females; 151 males; aged between 12-44 years), who competed at the 2014 sport poomsae taekwondo competition, participated in this study. The prevalence rate of COP and possible risk factors associated with COP were analyzed by using Chi-square tests and independent t-tests. A total of 173 athletes reported that they experienced COP (65.8%; 95% confidence interval [CI]: 60.5-71.5). Female athletes showed a higher prevalence rate than their male counterparts (75.9% vs. 58.3%). Lower body (61.5%) and knee joints (26.4%) were the two primarily injured body part. A total of 101 athletes reported that they injured in the previous year. Among those, 81.2% were suffered from COP. The technique that caused pain most frequently was side-kick among females and front-kick among males. Prevalence rates of COP were significantly different by sex, education level, training hour, and a history of injury. The prevalence of COP is high among sport poomsae taekwondo athletes. Competitors who are female, have a history of injury, and train for extended hours were more likely to experience COP. To identify other potential risk factors of COP in sport poomsae taekwondo, more research is needed to build upon the findings.

  14. Prevalence of HIV infection among pregnant women in Newfoundland.

    Science.gov (United States)

    Ratnam, S; Hogan, K; Hankins, C

    1996-04-01

    To determine the prevalence of HIV infection among pregnant women in Newfoundland. Anonymous unlinked seroprevalence study. Newfoundland. A total of 14911 women receiving prenatal care or undergoing an abortion, representing nearly all pregnancies in Newfoundland from Nov. 1, 1991, to Oct. 31, 1993. HIV antibody status, as determined by enzyme immunoassay of leftover serum samples (initially obtained for routine screening) and confirmation of reactive samples by the Western blot technique, health region of residence, and age group. Of the 14911 serum samples 13 were positive for HIV, for an overall crude prevalence rate of 1 per 1147 or 8.7 per 10000 pregnant women (95% confidence interval [CI] 4.7 to 14.9). Seven of the positive samples were from women residing in the Eastern Health Region of the province, for a crude prevalence rate of 1 per 376 or 26.6 per 10000 pregnant women (95% CI 10.7 to 54.8) for that region. All women found to be HIV positive were 15 to 29 years of age, the peak prevalence (20.8 per 10000 pregnant women [95% CI 9.5 to 39.4]) was observed among those 20 to 24 years. The overall prevalence rate of 8.7 per 10 000 pregnant women in Newfoundland is the highest provincial rate recorded among those from similar studies in Canada. Although it may be concluded that there are an estimated 125 HIV-positive women of childbearing age in Newfoundland (95% CI 67 to 213), the age-adjusted estimate is 84 (95% CI 36 to 131). This study provides an independent confirmation of an outbreak of HIV infection among women in the Eastern Health Region of the province.

  15. Prevalence of amblyopia and strabismus in young singaporean chinese children.

    Science.gov (United States)

    Chia, Audrey; Dirani, Mohamed; Chan, Yiong-Huak; Gazzard, Gus; Au Eong, Kah-Guan; Selvaraj, Prabakaran; Ling, Yvonne; Quah, Boon-Long; Young, Terri L; Mitchell, Paul; Varma, Rohit; Wong, Tien-Yin; Saw, Seang-Mei

    2010-07-01

    PURPOSE. To determine the prevalence of amblyopia and strabismus in young Singaporean Chinese children. METHODS. Enrolled in the study were 3009 Singaporean children, aged 6 to 72 months. All underwent complete eye examinations and cycloplegic refraction. Visual acuity (VA) was measured with a logMAR chart when possible and the Sheridan-Gardner test when not. Strabismus was defined as any manifest tropia. Unilateral amblyopia was defined as a 2-line difference between eyes with VA or =1.00 D for hyperopia, > or =3.00 D for myopia, and > or =1.50 D for astigmatism), strabismus, or past or present visual axis obstruction. Bilateral amblyopia was defined as VA in both eyes or =4.00 D, myopia or =2.50 D, or past or present visual axis obstruction. RESULTS. The amblyopia prevalence in children aged 30 to 72 months was 1.19% (95% confidence interval [CI], 0.73-1.83) with no age (P = 0.37) or sex (P = 0.22) differences. Unilateral amblyopia (0.83%) was twice as frequent as bilateral amblyopia (0.36%). The most frequent causes of amblyopia were refractive error (85%) and strabismus (15%); anisometropic astigmatism >1.50 D (42%) and isometropic astigmatism >2.50 D (29%) were frequent refractive errors. The prevalence of strabismus in children aged 6 to 72 months was 0.80% (95% CI, 0.51-1.19), with no sex (P = 0.52) or age (P = 0.08) effects. The exotropia-esotropia ratio was 7:1, with most exotropia being intermittent (63%). Of children with amblyopia, 15.0% had strabismus, whereas 12.5% of children with strabismus had amblyopia. CONCLUSIONS. The prevalence of amblyopia was similar, whereas the prevalence of strabismus was lower than in other populations.

  16. Prevalence of chronic kidney disease in Peruvian primary care setting.

    Science.gov (United States)

    Herrera-Añazco, Percy; Taype-Rondan, Alvaro; Lazo-Porras, María; Alberto Quintanilla, E; Ortiz-Soriano, Victor Manuel; Hernandez, Adrian V

    2017-07-19

    Chronic Kidney Disease (CKD) is a worldwide public health problem. There are few studies in Latin America, especially in primary care settings. Our objective was to determine the prevalence, stages, and associated factors of CKD in primary care setting. We did a retrospective secondary analysis of a database from the Diabetes and Hypertension Primary Care Center of the Peruvian Social Security System (EsSalud) in Lima, Peru. We defined CKD as the presence of eGFR 30 mg/day in 24 h, according to Kidney Disease: Improving Global Outcomes (KDIGO). Factors associated with CKD were evaluated with Poisson Regression models; these factors included age, gender, type 2 diabetes mellitus (DM2), hypertension (HTN), body mass index (BMI), and uric acid. Associations were described as crude and adjusted prevalence ratios (PR) and their 95% confidence intervals (95% CI). We evaluated 1211 patients (women [59%], mean age 65.8 years [SD: 12.7]). Prevalence of CKD was 18%. Using the estimated glomerular filtration rate (eGFR), the prevalence was 9.3% (95% CI 5.3 - 13.3) in patients without HTN or DM2; 20.2% (95% CI 17.6 - 22.8) in patients with HTN, and 23.9% (95% CI 19.4 - 28.4) in patients with DM2. The most common stages were 1 and 2 with 41.5% and 48%, respectively. Factors associated with CKD in the adjusted analysis were: age in years (PR = 1.03, 95% CI 1.01 - 1.04), DM2 (PR = 3.37, 95% CI 1.09 - 10.39), HTN plus DM2 (PR = 3.90, 95% CI 1.54 - 9.88), and uric acid from 5 to DM2, older age and hyperuricemia have higher prevalence of CKD.

  17. Prevalence of Helicobacter pylori infection and histologic gastritis in asymptomatic persons.

    Science.gov (United States)

    Dooley, C P; Cohen, H; Fitzgibbons, P L; Bauer, M; Appleman, M D; Perez-Perez, G I; Blaser, M J

    1989-12-07

    We estimated the prevalences of Helicobacter pylori (formerly called Campylobacter pylori) infection and histologic gastritis in 113 asymptomatic persons, using endoscopic biopsy of the gastric antrum and corpus. Unsuspected lesions, mainly mucosal erosions, were revealed at endoscopy in 16 subjects (14 percent). Gastritis was found in 42 subjects (37 percent), of whom 36 (32 percent of the total) were found to be infected with H. pylori on the basis of hematoxylin-eosin staining. H. pylori was not found in any of the 71 subjects with normal histologic features. Gastritis and H. pylori were noted in both the antrum and corpus in 75 percent of those infected (n = 27). The prevalence of H. pylori infection increased from 10 percent (2 of 20 subjects) in those between the ages of 18 and 29, to 47 percent (7 of 15) in those between the ages of 60 and 69, but the effect of age did not reach statistical significance. The prevalence of gastritis increased significantly with advancing age. Stepwise logistic regression analysis revealed that the relative risk for H. pylori infection associated with recent (within six months) antibiotic use was 5.8 (95 percent confidence interval, 1.5 to 22.1), whereas the relative risk was 6.5 (95 percent confidence interval, 1.4 to 29.2) for those who had never used bismuth compounds. We conclude that histologic gastritis and H. pylori infection commonly occur in the stomach of apparently normal persons and increase in prevalence with advancing age. All the subjects with H. pylori infection had gastritis, suggesting a possible etiologic role for the bacterium in the histologic lesion.

  18. Sleep disturbance in patients with an implantable cardioverter defibrillator: Prevalence, predictors and impact on health status.

    Science.gov (United States)

    Habibović, M; Mudde, L; Pedersen, S S; Schoormans, D; Widdershoven, J; Denollet, J

    2017-12-01

    Sleep disturbances are highly prevalent in patients with cardiac diseases and associated with poor health outcomes. However, little is known about sleep disturbance in patients with an implantable cardioverter defibrillator. We examined the prevalence and predictors of sleep disturbance and the impact on perceived health status in a Dutch cohort of implantable cardioverter defibrillator patients. Patients ( n=195) enrolled in the Web-based distress program for implantable cardioverter defibrillator patients (WEBCARE) trial completed questionnaires at the time of implantable cardioverter defibrillator implantation, three, six and 12 months afterwards. Sleep disturbance was assessed with the corresponding item #3 of the Patient Health Questionnaire 9. At baseline, 67% ( n=130) reported sleep disturbance (cut off ≥1). One year later, the prevalence was 57% ( n=112). Younger age (odds ratio=0.96, 95% confidence interval 0.92-0.99; p=0.012) and high negative affectivity/low social inhibition (odds ratio=4.47, 95% confidence interval 1.52-13.17; p=0.007) were associated with sleep disturbance at 12 months in adjusted analyses. Sleep disturbance was not associated with health status at 12 months. Charlson Comorbidity Index, anxiety, Type D personality and high negative affectivity/low social inhibition were associated with impaired health status at follow-up. Sleep disturbance was highly prevalent in patients with an implantable cardioverter defibrillator. Younger age and high negative affectivity predicted sleep disturbance 12 months post-implantation independent of other demographic, clinical, intervention and psychological covariates. Sleep disturbance was not associated with impaired health status at the 12-month follow-up.

  19. Anomalous Evidence, Confidence Change, and Theory Change.

    Science.gov (United States)

    Hemmerich, Joshua A; Van Voorhis, Kellie; Wiley, Jennifer

    2016-08-01

    A novel experimental paradigm that measured theory change and confidence in participants' theories was used in three experiments to test the effects of anomalous evidence. Experiment 1 varied the amount of anomalous evidence to see if "dose size" made incremental changes in confidence toward theory change. Experiment 2 varied whether anomalous evidence was convergent (of multiple types) or replicating (similar finding repeated). Experiment 3 varied whether participants were provided with an alternative theory that explained the anomalous evidence. All experiments showed that participants' confidence changes were commensurate with the amount of anomalous evidence presented, and that larger decreases in confidence predicted theory changes. Convergent evidence and the presentation of an alternative theory led to larger confidence change. Convergent evidence also caused more theory changes. Even when people do not change theories, factors pertinent to the evidence and alternative theories decrease their confidence in their current theory and move them incrementally closer to theory change. Copyright © 2015 Cognitive Science Society, Inc.

  20. Empowerment as Interactions that Generate Self-Confidence

    DEFF Research Database (Denmark)

    Poder, Poul

    2010-01-01

    in empowerment programmes (Dahl 1999: 51; Jacobsen/Thorsvik 2007: 188). However, such programmes are often unsuccessful (Wilson 2004; Edwards/Wajcman 2005), and the processes that lead to effective empowerment have not yet been sufficiently understood (Conger/Kanungo 1988; Eylon 1998: 17). This chapter aims...... – is essential to empowerment. For example, DuBrien advises managers to: ‘Look for evidence of self-confidence in handling past assignments. It takes self-confidence to handle decisions on your own. (Of course, you could argue that being empowered builds self-confidence). Look for at least some past displays...... of self-confidence’ (DuBrien 2000: 228f.). That one should look for past signs of self-confidence indicates that self-confidence in present efforts cannot be taken for granted. Moreover, the suggestion that being formally and structurally empowered builds self-confidence is not self-evident, since...