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Sample records for lens model meta-analysis

  1. A Bayesian Nonparametric Meta-Analysis Model

    Science.gov (United States)

    Karabatsos, George; Talbott, Elizabeth; Walker, Stephen G.

    2015-01-01

    In a meta-analysis, it is important to specify a model that adequately describes the effect-size distribution of the underlying population of studies. The conventional normal fixed-effect and normal random-effects models assume a normal effect-size population distribution, conditionally on parameters and covariates. For estimating the mean overall…

  2. Meta-analysis a structural equation modeling approach

    CERN Document Server

    Cheung, Mike W-L

    2015-01-01

    Presents a novel approach to conducting meta-analysis using structural equation modeling. Structural equation modeling (SEM) and meta-analysis are two powerful statistical methods in the educational, social, behavioral, and medical sciences. They are often treated as two unrelated topics in the literature. This book presents a unified framework on analyzing meta-analytic data within the SEM framework, and illustrates how to conduct meta-analysis using the metaSEM package in the R statistical environment. Meta-Analysis: A Structural Equation Modeling Approach begins by introducing the impo

  3. Lens Model

    DEFF Research Database (Denmark)

    Nash, Ulrik William

    2014-01-01

    Firms consist of people who make decisions to achieve goals. How do these people develop the expectations which underpin the choices they make? The lens model provides one answer to this question. It was developed by cognitive psychologist Egon Brunswik (1952) to illustrate his theory...

  4. Early Start DENVER Model: A Meta - analysis

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    Jane P. Canoy

    2015-11-01

    Full Text Available Each child with Autism Spectrum Disorder has different symptoms, skills and types of impairment or disorder with other children. This is why the word “spectrum” is included in this disorder. Eapen, Crncec, and Walter, 2013 claimed that there was an emerging evidence that early interventions gives the greatest capacity of child’s development during their first years of life as “brain plasticity” are high during this period. With this, the only intervention program model for children as young as 18 months that has been validated in a randomized clinical trial is “Early Start Denver Model” (ESDM. This study aimed to determine the effectiveness of the outcome of “Early Start Denver Model” (ESDM towards young children with Autism Spectrum Disorders. This study made use of meta-analysis method. In this study, the researcher utilized studies related to “Early Start Denver Model (ESDM” which is published in a refereed journal which are all available online. There were five studies included which totals 149 children exposed to ESDM. To examine the “pooled effects” of ESDM in a variety of outcomes, a meta-analytic procedure was performed after the extraction of data of the concrete outcomes. Comprehensive Meta Analysis Version 3.3.070 was used to analyze the data.  The effectiveness of the outcome of “Early Start Denver Model” towards young children with Autism Spectrum Disorders (ASD highly depends on the intensity of intervention and the younger child age. This study would provide the basis in effectively implementing an early intervention to children with autism such as the “Early Start Denver Model” (ESDM that would show great outcome effects to those children that has “Autism Spectrum Disorder”.

  5. Statistical Models and Methods for Network Meta-Analysis.

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    Madden, L V; Piepho, H-P; Paul, P A

    2016-08-01

    Meta-analysis, the methodology for analyzing the results from multiple independent studies, has grown tremendously in popularity over the last four decades. Although most meta-analyses involve a single effect size (summary result, such as a treatment difference) from each study, there are often multiple treatments of interest across the network of studies in the analysis. Multi-treatment (or network) meta-analysis can be used for simultaneously analyzing the results from all the treatments. However, the methodology is considerably more complicated than for the analysis of a single effect size, and there have not been adequate explanations of the approach for agricultural investigations. We review the methods and models for conducting a network meta-analysis based on frequentist statistical principles, and demonstrate the procedures using a published multi-treatment plant pathology data set. A major advantage of network meta-analysis is that correlations of estimated treatment effects are automatically taken into account when an appropriate model is used. Moreover, treatment comparisons may be possible in a network meta-analysis that are not possible in a single study because all treatments of interest may not be included in any given study. We review several models that consider the study effect as either fixed or random, and show how to interpret model-fitting output. We further show how to model the effect of moderator variables (study-level characteristics) on treatment effects, and present one approach to test for the consistency of treatment effects across the network. Online supplemental files give explanations on fitting the network meta-analytical models using SAS.

  6. The Success of Linear Bootstrapping Models: Decision Domain-, Expertise-, and Criterion-Specific Meta-Analysis

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    Kaufmann, Esther; Wittmann, Werner W.

    2016-01-01

    The success of bootstrapping or replacing a human judge with a model (e.g., an equation) has been demonstrated in Paul Meehl’s (1954) seminal work and bolstered by the results of several meta-analyses. To date, however, analyses considering different types of meta-analyses as well as the potential dependence of bootstrapping success on the decision domain, the level of expertise of the human judge, and the criterion for what constitutes an accurate decision have been missing from the literature. In this study, we addressed these research gaps by conducting a meta-analysis of lens model studies. We compared the results of a traditional (bare-bones) meta-analysis with findings of a meta-analysis of the success of bootstrap models corrected for various methodological artifacts. In line with previous studies, we found that bootstrapping was more successful than human judgment. Furthermore, bootstrapping was more successful in studies with an objective decision criterion than in studies with subjective or test score criteria. We did not find clear evidence that the success of bootstrapping depended on the decision domain (e.g., education or medicine) or on the judge’s level of expertise (novice or expert). Correction of methodological artifacts increased the estimated success of bootstrapping, suggesting that previous analyses without artifact correction (i.e., traditional meta-analyses) may have underestimated the value of bootstrapping models. PMID:27327085

  7. Bayesian nonparametric meta-analysis using Polya tree mixture models.

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    Branscum, Adam J; Hanson, Timothy E

    2008-09-01

    Summary. A common goal in meta-analysis is estimation of a single effect measure using data from several studies that are each designed to address the same scientific inquiry. Because studies are typically conducted in geographically disperse locations, recent developments in the statistical analysis of meta-analytic data involve the use of random effects models that account for study-to-study variability attributable to differences in environments, demographics, genetics, and other sources that lead to heterogeneity in populations. Stemming from asymptotic theory, study-specific summary statistics are modeled according to normal distributions with means representing latent true effect measures. A parametric approach subsequently models these latent measures using a normal distribution, which is strictly a convenient modeling assumption absent of theoretical justification. To eliminate the influence of overly restrictive parametric models on inferences, we consider a broader class of random effects distributions. We develop a novel hierarchical Bayesian nonparametric Polya tree mixture (PTM) model. We present methodology for testing the PTM versus a normal random effects model. These methods provide researchers a straightforward approach for conducting a sensitivity analysis of the normality assumption for random effects. An application involving meta-analysis of epidemiologic studies designed to characterize the association between alcohol consumption and breast cancer is presented, which together with results from simulated data highlight the performance of PTMs in the presence of nonnormality of effect measures in the source population.

  8. Intraocular lens dislocation in pseudoexfoliation: a systematic review and meta-analysis.

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    Vazquez-Ferreiro, Pedro; Carrera-Hueso, Francisco J; Fikri-Benbrahim, Narjis; Barreiro-Rodriguez, Lidia; Diaz-Rey, Marta; Ramón Barrios, María Auxiliadora

    2017-05-01

    To evaluate the impact of pseudoexfoliation syndrome on intraocular lens (IOL) dislocation after phacoemulsification cataract surgery and explore possible associations related to surgical technique. We systematically searched the MEDLINE, Embase, Web of Science, Cochrane, and Lilacs databases and grey literature sources and identified (on March 1, 2016) 14 cohort and case-control studies comparing IOL dislocation in patients with and without pseudoexfoliation syndrome who had undergone phacoemulsification. Study quality was assessed using the STROBE scale. An inverse-variance fixed-effects model was used to calculate weighted odds ratios (ORs) and 95% confidence intervals (CI). The pooled analysis yielded an OR of 6.02 (95% CI: 3.7, 9.79) for IOL dislocation in patients with pseudoexfoliation, and similarly, high ORs were detected for both early and late (3 months after surgery) dislocation (OR 5.26; 95% CI: 1.05; 26.32 versus OR 6.02; 95% CI: 3.67; 10.17). No significant associations were detected when the results were stratified by year, incision size or use of hooks or retractors. Patients with pseudoexfoliation syndrome have a high risk of late IOL dislocation after phacoemulsification cataract surgery, and this risk may be related to the use of large incisions and hooks or retractors. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  9. Alcohol Involvement and the Five-Factor Model of Personality: A Meta-Analysis

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    Malouff, John M.; Thorsteinsson, Einar B.; Rooke, Sally E.; Schutte, Nicola S.

    2007-01-01

    The purpose of this meta-analysis was to quantify the relationship between the Five-Factor Model of personality and alcohol involvement and to identify moderators of the relationship. The meta-analysis included 20 studies, 119 effect sizes, and 7,886 participants. Possible moderators examined included: five-factor rating type (self vs. other);…

  10. Academic inequality through the lens of community ecology: a meta-analysis

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    Akira S. Mori

    2015-12-01

    Full Text Available Ecological assemblages are generally characterized by a few dominant species and numerous others. Such unequal distributions of dominance also emerge in human society, including in scientific communities. Here, based on formal community ecological analyses, we show the temporal trends in the number of scientific publication in the discipline of “ecology.” Based on this, we infer possible factors causing the imbalance of reputation and dominance among countries. We relied on 454 ecological meta-analysis papers published from 1998 to 2014, which sourced over 29,000 original publications. Formal meta-analyses are essential for synthesizing findings from individual studies and are critical for assessing issues and informing policy. We found that, despite the rapid expansion of outlets for ecology papers (analogous to an increase in carrying capacity, in ecological systems, country diversity as determined from first author affiliations (analogous to species diversity did not increase. Furthermore, a country identity was more powerful than the popularity of the scientific topic and affected the chance of publication in high-profile journals, independent of the potential novelty of findings and arguments of the papers, suggesting possible academic injustice. Consequently, a rank order and hierarchy has been gradually formed among countries. Notably, this country-dominance rank is not only specific to this scientific domain but also universal across different societal situations including sports and economics, further emphasizing that inequality and hierarchical structure exist even in modern human society. Our study demonstrates a need for having robust frameworks to facilitate equality and diversity in the scientific domain in order to better inform society and policy.

  11. Academic inequality through the lens of community ecology: a meta-analysis.

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    Mori, Akira S; Qian, Shenhua; Tatsumi, Shinichi

    2015-01-01

    Ecological assemblages are generally characterized by a few dominant species and numerous others. Such unequal distributions of dominance also emerge in human society, including in scientific communities. Here, based on formal community ecological analyses, we show the temporal trends in the number of scientific publication in the discipline of "ecology." Based on this, we infer possible factors causing the imbalance of reputation and dominance among countries. We relied on 454 ecological meta-analysis papers published from 1998 to 2014, which sourced over 29,000 original publications. Formal meta-analyses are essential for synthesizing findings from individual studies and are critical for assessing issues and informing policy. We found that, despite the rapid expansion of outlets for ecology papers (analogous to an increase in carrying capacity, in ecological systems), country diversity as determined from first author affiliations (analogous to species diversity) did not increase. Furthermore, a country identity was more powerful than the popularity of the scientific topic and affected the chance of publication in high-profile journals, independent of the potential novelty of findings and arguments of the papers, suggesting possible academic injustice. Consequently, a rank order and hierarchy has been gradually formed among countries. Notably, this country-dominance rank is not only specific to this scientific domain but also universal across different societal situations including sports and economics, further emphasizing that inequality and hierarchical structure exist even in modern human society. Our study demonstrates a need for having robust frameworks to facilitate equality and diversity in the scientific domain in order to better inform society and policy.

  12. Linear mixed model approach to network meta-analysis for continuous outcomes in periodontal research.

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    Tu, Yu-Kang

    2015-02-01

    Analysing continuous outcomes for network meta-analysis by means of linear mixed models is a great challenge, as it requires statistical software packages to specify special patterns of model error variance and covariance structure. This article demonstrates a non-Bayesian approach to network meta-analysis for continuous outcomes in periodontal research with a special focus on the adjustment of data dependency. Seventeen studies on guided tissue regeneration were used to illustrate how the proposed linear mixed models for network meta-analysis of continuous outcomes. Arm-based network meta-analysis use treatment arms from each study as the unit of analysis; when patients are randomly assigned to each arm, data are deemed independent and therefore no adjustment is required for multi-arm trials. Trial-based network meta-analysis use treatment contrasts as the unit of analysis, and therefore treatment contrasts within a multi-arm trial are not independent. This data dependency occurs also in split-mouth studies, and adjustments for data dependency are therefore required. Arm-based analysis is the preferred approach to network meta-analysis, when all included studies use the parallel group design and some compare more than two treatment arms. When included studies used designs that yield dependent data, the trial-based analysis is the preferred approach. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Gene Level Meta-Analysis of Quantitative Traits by Functional Linear Models.

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    Fan, Ruzong; Wang, Yifan; Boehnke, Michael; Chen, Wei; Li, Yun; Ren, Haobo; Lobach, Iryna; Xiong, Momiao

    2015-08-01

    Meta-analysis of genetic data must account for differences among studies including study designs, markers genotyped, and covariates. The effects of genetic variants may differ from population to population, i.e., heterogeneity. Thus, meta-analysis of combining data of multiple studies is difficult. Novel statistical methods for meta-analysis are needed. In this article, functional linear models are developed for meta-analyses that connect genetic data to quantitative traits, adjusting for covariates. The models can be used to analyze rare variants, common variants, or a combination of the two. Both likelihood-ratio test (LRT) and F-distributed statistics are introduced to test association between quantitative traits and multiple variants in one genetic region. Extensive simulations are performed to evaluate empirical type I error rates and power performance of the proposed tests. The proposed LRT and F-distributed statistics control the type I error very well and have higher power than the existing methods of the meta-analysis sequence kernel association test (MetaSKAT). We analyze four blood lipid levels in data from a meta-analysis of eight European studies. The proposed methods detect more significant associations than MetaSKAT and the P-values of the proposed LRT and F-distributed statistics are usually much smaller than those of MetaSKAT. The functional linear models and related test statistics can be useful in whole-genome and whole-exome association studies. Copyright © 2015 by the Genetics Society of America.

  14. A Meta-Analysis of the Five-Factor Model of Personality and Academic Performance

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    Poropat, Arthur E.

    2009-01-01

    This article reports a meta-analysis of personality-academic performance relationships, based on the 5-factor model, in which cumulative sample sizes ranged to over 70,000. Most analyzed studies came from the tertiary level of education, but there were similar aggregate samples from secondary and tertiary education. There was a comparatively…

  15. The Five-Factor Model of Personality and Smoking: A Meta-Analysis

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    Malouff, John M.; Thorsteinsson, Einar B.; Schutte, Nicola S.

    2006-01-01

    This article describes a meta-analysis of the relationship between the Five-Factor Model of personality and smoking. The results, based on nine studies and a total of 4,730 participants, show that smoking was associated with the following five-factor traits: low conscientiousness, low agreeableness, and high neuroticism. Smokers outside Canada and…

  16. The Effect of Learning Cycle Models on Achievement of Students: A Meta-Analysis Study

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    Sarac, Hakan

    2018-01-01

    In the study, a meta-analysis was conducted to determine the effect of the use of the learning cycle model on the achievements of the students. Doctorate and master theses, made between 2007 and 2016, were searched using the keywords in Turkish and English. As a result of the screening, a total of 123 dissertations, which used learning cycle…

  17. Use of generalized linear mixed models for network meta-analysis.

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    Tu, Yu-Kang

    2014-10-01

    In the past decade, a new statistical method-network meta-analysis-has been developed to address limitations in traditional pairwise meta-analysis. Network meta-analysis incorporates all available evidence into a general statistical framework for comparisons of multiple treatments. Bayesian network meta-analysis, as proposed by Lu and Ades, also known as "mixed treatments comparisons," provides a flexible modeling framework to take into account complexity in the data structure. This article shows how to implement the Lu and Ades model in the frequentist generalized linear mixed model. Two examples are provided to demonstrate how centering the covariates for random effects estimation within each trial can yield correct estimation of random effects. Moreover, under the correct specification for random effects estimation, the dummy coding and contrast basic parameter coding schemes will yield the same results. It is straightforward to incorporate covariates, such as moderators and confounders, into the generalized linear mixed model to conduct meta-regression for multiple treatment comparisons. Moreover, this approach may be extended easily to other types of outcome variables, such as continuous, counts, and multinomial. © The Author(s) 2014.

  18. Meta-analysis with R

    CERN Document Server

    Schwarzer, Guido; Rücker, Gerta

    2015-01-01

    This book provides a comprehensive introduction to performing meta-analysis using the statistical software R. It is intended for quantitative researchers and students in the medical and social sciences who wish to learn how to perform meta-analysis with R. As such, the book introduces the key concepts and models used in meta-analysis. It also includes chapters on the following advanced topics: publication bias and small study effects; missing data; multivariate meta-analysis, network meta-analysis; and meta-analysis of diagnostic studies.  .

  19. Bayesian meta-analysis models for microarray data: a comparative study

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    Song Joon J

    2007-03-01

    Full Text Available Abstract Background With the growing abundance of microarray data, statistical methods are increasingly needed to integrate results across studies. Two common approaches for meta-analysis of microarrays include either combining gene expression measures across studies or combining summaries such as p-values, probabilities or ranks. Here, we compare two Bayesian meta-analysis models that are analogous to these methods. Results Two Bayesian meta-analysis models for microarray data have recently been introduced. The first model combines standardized gene expression measures across studies into an overall mean, accounting for inter-study variability, while the second combines probabilities of differential expression without combining expression values. Both models produce the gene-specific posterior probability of differential expression, which is the basis for inference. Since the standardized expression integration model includes inter-study variability, it may improve accuracy of results versus the probability integration model. However, due to the small number of studies typical in microarray meta-analyses, the variability between studies is challenging to estimate. The probability integration model eliminates the need to model variability between studies, and thus its implementation is more straightforward. We found in simulations of two and five studies that combining probabilities outperformed combining standardized gene expression measures for three comparison values: the percent of true discovered genes in meta-analysis versus individual studies; the percent of true genes omitted in meta-analysis versus separate studies, and the number of true discovered genes for fixed levels of Bayesian false discovery. We identified similar results when pooling two independent studies of Bacillus subtilis. We assumed that each study was produced from the same microarray platform with only two conditions: a treatment and control, and that the data sets

  20. Beta-binomial model for meta-analysis of odds ratios.

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    Bakbergenuly, Ilyas; Kulinskaya, Elena

    2017-05-20

    In meta-analysis of odds ratios (ORs), heterogeneity between the studies is usually modelled via the additive random effects model (REM). An alternative, multiplicative REM for ORs uses overdispersion. The multiplicative factor in this overdispersion model (ODM) can be interpreted as an intra-class correlation (ICC) parameter. This model naturally arises when the probabilities of an event in one or both arms of a comparative study are themselves beta-distributed, resulting in beta-binomial distributions. We propose two new estimators of the ICC for meta-analysis in this setting. One is based on the inverted Breslow-Day test, and the other on the improved gamma approximation by Kulinskaya and Dollinger (2015, p. 26) to the distribution of Cochran's Q. The performance of these and several other estimators of ICC on bias and coverage is studied by simulation. Additionally, the Mantel-Haenszel approach to estimation of ORs is extended to the beta-binomial model, and we study performance of various ICC estimators when used in the Mantel-Haenszel or the inverse-variance method to combine ORs in meta-analysis. The results of the simulations show that the improved gamma-based estimator of ICC is superior for small sample sizes, and the Breslow-Day-based estimator is the best for n⩾100. The Mantel-Haenszel-based estimator of OR is very biased and is not recommended. The inverse-variance approach is also somewhat biased for ORs≠1, but this bias is not very large in practical settings. Developed methods and R programs, provided in the Web Appendix, make the beta-binomial model a feasible alternative to the standard REM for meta-analysis of ORs. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2017 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  1. A random effects meta-analysis model with Box-Cox transformation.

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    Yamaguchi, Yusuke; Maruo, Kazushi; Partlett, Christopher; Riley, Richard D

    2017-07-19

    In a random effects meta-analysis model, true treatment effects for each study are routinely assumed to follow a normal distribution. However, normality is a restrictive assumption and the misspecification of the random effects distribution may result in a misleading estimate of overall mean for the treatment effect, an inappropriate quantification of heterogeneity across studies and a wrongly symmetric prediction interval. We focus on problems caused by an inappropriate normality assumption of the random effects distribution, and propose a novel random effects meta-analysis model where a Box-Cox transformation is applied to the observed treatment effect estimates. The proposed model aims to normalise an overall distribution of observed treatment effect estimates, which is sum of the within-study sampling distributions and the random effects distribution. When sampling distributions are approximately normal, non-normality in the overall distribution will be mainly due to the random effects distribution, especially when the between-study variation is large relative to the within-study variation. The Box-Cox transformation addresses this flexibly according to the observed departure from normality. We use a Bayesian approach for estimating parameters in the proposed model, and suggest summarising the meta-analysis results by an overall median, an interquartile range and a prediction interval. The model can be applied for any kind of variables once the treatment effect estimate is defined from the variable. A simulation study suggested that when the overall distribution of treatment effect estimates are skewed, the overall mean and conventional I 2 from the normal random effects model could be inappropriate summaries, and the proposed model helped reduce this issue. We illustrated the proposed model using two examples, which revealed some important differences on summary results, heterogeneity measures and prediction intervals from the normal random effects model. The

  2. Applying Meta-Analysis to Structural Equation Modeling

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    Hedges, Larry V.

    2016-01-01

    Structural equation models play an important role in the social sciences. Consequently, there is an increasing use of meta-analytic methods to combine evidence from studies that estimate the parameters of structural equation models. Two approaches are used to combine evidence from structural equation models: A direct approach that combines…

  3. Meta-analysis of studies with bivariate binary outcomes: a marginal beta-binomial model approach.

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    Chen, Yong; Hong, Chuan; Ning, Yang; Su, Xiao

    2016-01-15

    When conducting a meta-analysis of studies with bivariate binary outcomes, challenges arise when the within-study correlation and between-study heterogeneity should be taken into account. In this paper, we propose a marginal beta-binomial model for the meta-analysis of studies with binary outcomes. This model is based on the composite likelihood approach and has several attractive features compared with the existing models such as bivariate generalized linear mixed model (Chu and Cole, 2006) and Sarmanov beta-binomial model (Chen et al., 2012). The advantages of the proposed marginal model include modeling the probabilities in the original scale, not requiring any transformation of probabilities or any link function, having closed-form expression of likelihood function, and no constraints on the correlation parameter. More importantly, because the marginal beta-binomial model is only based on the marginal distributions, it does not suffer from potential misspecification of the joint distribution of bivariate study-specific probabilities. Such misspecification is difficult to detect and can lead to biased inference using currents methods. We compare the performance of the marginal beta-binomial model with the bivariate generalized linear mixed model and the Sarmanov beta-binomial model by simulation studies. Interestingly, the results show that the marginal beta-binomial model performs better than the Sarmanov beta-binomial model, whether or not the true model is Sarmanov beta-binomial, and the marginal beta-binomial model is more robust than the bivariate generalized linear mixed model under model misspecifications. Two meta-analyses of diagnostic accuracy studies and a meta-analysis of case-control studies are conducted for illustration. Copyright © 2015 John Wiley & Sons, Ltd.

  4. Standardizing effect size from linear regression models with log-transformed variables for meta-analysis.

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    Rodríguez-Barranco, Miguel; Tobías, Aurelio; Redondo, Daniel; Molina-Portillo, Elena; Sánchez, María José

    2017-03-17

    Meta-analysis is very useful to summarize the effect of a treatment or a risk factor for a given disease. Often studies report results based on log-transformed variables in order to achieve the principal assumptions of a linear regression model. If this is the case for some, but not all studies, the effects need to be homogenized. We derived a set of formulae to transform absolute changes into relative ones, and vice versa, to allow including all results in a meta-analysis. We applied our procedure to all possible combinations of log-transformed independent or dependent variables. We also evaluated it in a simulation based on two variables either normally or asymmetrically distributed. In all the scenarios, and based on different change criteria, the effect size estimated by the derived set of formulae was equivalent to the real effect size. To avoid biased estimates of the effect, this procedure should be used with caution in the case of independent variables with asymmetric distributions that significantly differ from the normal distribution. We illustrate an application of this procedure by an application to a meta-analysis on the potential effects on neurodevelopment in children exposed to arsenic and manganese. The procedure proposed has been shown to be valid and capable of expressing the effect size of a linear regression model based on different change criteria in the variables. Homogenizing the results from different studies beforehand allows them to be combined in a meta-analysis, independently of whether the transformations had been performed on the dependent and/or independent variables.

  5. Standardizing effect size from linear regression models with log-transformed variables for meta-analysis

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    Miguel Rodríguez-Barranco

    2017-03-01

    Full Text Available Abstract Background Meta-analysis is very useful to summarize the effect of a treatment or a risk factor for a given disease. Often studies report results based on log-transformed variables in order to achieve the principal assumptions of a linear regression model. If this is the case for some, but not all studies, the effects need to be homogenized. Methods We derived a set of formulae to transform absolute changes into relative ones, and vice versa, to allow including all results in a meta-analysis. We applied our procedure to all possible combinations of log-transformed independent or dependent variables. We also evaluated it in a simulation based on two variables either normally or asymmetrically distributed. Results In all the scenarios, and based on different change criteria, the effect size estimated by the derived set of formulae was equivalent to the real effect size. To avoid biased estimates of the effect, this procedure should be used with caution in the case of independent variables with asymmetric distributions that significantly differ from the normal distribution. We illustrate an application of this procedure by an application to a meta-analysis on the potential effects on neurodevelopment in children exposed to arsenic and manganese. Conclusions The procedure proposed has been shown to be valid and capable of expressing the effect size of a linear regression model based on different change criteria in the variables. Homogenizing the results from different studies beforehand allows them to be combined in a meta-analysis, independently of whether the transformations had been performed on the dependent and/or independent variables.

  6. Emotional intelligence: an integrative meta-analysis and cascading model.

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    Joseph, Dana L; Newman, Daniel A

    2010-01-01

    Research and valid practice in emotional intelligence (EI) have been impeded by lack of theoretical clarity regarding (a) the relative roles of emotion perception, emotion understanding, and emotion regulation facets in explaining job performance; (b) conceptual redundancy of EI with cognitive intelligence and Big Five personality; and (c) application of the EI label to 2 distinct sets of constructs (i.e., ability-based EI and mixed-based EI). In the current article, the authors propose and then test a theoretical model that integrates these factors. They specify a progressive (cascading) pattern among ability-based EI facets, in which emotion perception must causally precede emotion understanding, which in turn precedes conscious emotion regulation and job performance. The sequential elements in this progressive model are believed to selectively reflect Conscientiousness, cognitive ability, and Neuroticism, respectively. "Mixed-based" measures of EI are expected to explain variance in job performance beyond cognitive ability and personality. The cascading model of EI is empirically confirmed via meta-analytic data, although relationships between ability-based EI and job performance are shown to be inconsistent (i.e., EI positively predicts performance for high emotional labor jobs and negatively predicts performance for low emotional labor jobs). Gender and race differences in EI are also meta-analyzed. Implications for linking the EI fad in personnel selection to established psychological theory are discussed. Copyright 2009 APA, all rights reserved.

  7. Using Generalized Linear Mixed Models to Evaluate Inconsistency within a Network Meta-Analysis.

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    Tu, Yu-Kang

    2015-12-01

    Network meta-analysis compares multiple treatments by incorporating direct and indirect evidence into a general statistical framework. One issue with the validity of network meta-analysis is inconsistency between direct and indirect evidence within a loop formed by three treatments. Recently, the inconsistency issue has been explored further and a complex design-by-treatment interaction model proposed. The aim of this article was to show how to evaluate the design-by-treatment interaction model using the generalized linear mixed model. We proposed an arm-based approach to evaluating the design-by-treatment inconsistency, which is flexible in modeling different types of outcome variables. We used the smoking cessation data to compare results from our arm-based approach with those from the standard contrast-based approach. Because the contrast-based approach requires transformation of data, our example showed that such a transformation may yield biases in the treatment effect and inconsistency evaluation, when event rates were low in some treatments. We also compared contrast-based and arm-based models in the evaluation of design inconsistency when different heterogeneity variances were estimated, and the arm-based model yielded more accurate results. Because some statistical software commands can detect the collinearity among variables and automatically remove the redundant ones, we can use this advantage to help with placing the inconsistency parameters. This could be very useful for a network meta-analysis involving many designs and treatments. Copyright © 2015 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  8. bspmma: An R Package for Bayesian Semiparametric Models for Meta-Analysis

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    Deborah Burr

    2012-07-01

    Full Text Available We introduce an R package, bspmma, which implements a Dirichlet-based random effects model specific to meta-analysis. In meta-analysis, when combining effect estimates from several heterogeneous studies, it is common to use a random-effects model. The usual frequentist or Bayesian models specify a normal distribution for the true effects. However, in many situations, the effect distribution is not normal, e.g., it can have thick tails, be skewed, or be multi-modal. A Bayesian nonparametric model based on mixtures of Dirichlet process priors has been proposed in the literature, for the purpose of accommodating the non-normality. We review this model and then describe a competitor, a semiparametric version which has the feature that it allows for a well-defined centrality parameter convenient for determining whether the overall effect is significant. This second Bayesian model is based on a different version of the Dirichlet process prior, and we call it the "conditional Dirichlet model". The package contains functions to carry out analyses based on either the ordinary or the conditional Dirichlet model, functions for calculating certain Bayes factors that provide a check on the appropriateness of the conditional Dirichlet model, and functions that enable an empirical Bayes selection of the precision parameter of the Dirichlet process. We illustrate the use of the package on two examples, and give an interpretation of the results in these two different scenarios.

  9. META - ANALYSIS

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    Ivana Ilić

    2009-04-01

    Full Text Available Meta-analysis is a statistical and analytical method which combines and synthesizes different independent studies and integrates their results into a common result. In the past few years, there has been an increasing interest in meta-analysis from both medical researches and statisticians. One of the main targets of clinical research is to obtain reliable results, although clinical trials with the same topic often give contrasting results. Medical practice is strongly influenced by the results of clinical studies if they are brought to light through important scientific journals. This large amount of information often contains scattered data, and discordant conclusions, and sometimes it is very hard to define the quality and validity of each study. Today, a large number of biomedical journals give importance to articles using meta-analysis in their researches. By using meta-analysis as a method of summarizing, integrating and analyzing a large number of independent studies on the same topic and finally pooling their results into a common result, a researcher can achieve relevant, objective and unbiased conclusions, if the procedure is well-conducted and controlled by the experts. The aim of this paper is to provide the clinical researcher with the basic principles of meta-analysis and its concepts in order to perform a valid clinical study and to report results in the correct way. In today’s evidence-based medical practice, it is crucial for anyone who wants to deal seriously with the scientific work in the biomedical field to learn mathematical and statistical principles that build meta-analysis. In that way, this statistical method could be of great importance to the researcher who wants to respond to new demands of modern medical science.

  10. Endurance time is joint-specific: A modelling and meta-analysis investigation

    Science.gov (United States)

    Law, Laura A. Frey; Avin, Keith G.

    2010-01-01

    Static task intensity–endurance time (ET) relationships (e.g. Rohmert's curve) were first reported decades ago. However, a comprehensive meta-analysis to compare experimentally-observed ETs across bodily regions has not been reported. We performed a systematic literature review of ETs for static contractions, developed joint-specific power and exponential models of the intensity–ET relationships, and compared these models between each joint (ankle, trunk, hand/grip, elbow, knee, and shoulder) and the pooled data (generalised curve). 194 publications were found, representing a total of 369 data points. The power model provided the best fit to the experimental data. Significant intensity-dependent ET differences were predicted between each pair of joints. Overall, the ankle was most fatigue-resistant, followed by the trunk, hand/grip, elbow, knee and finally the shoulder was most fatigable. We conclude ET varies systematically between joints, in some cases with large effect sizes. Thus, a single generalised ET model does not adequately represent fatigue across joints. Statement of Relevance Rohmert curves have been used in ergonomic analyses of fatigue, as there are limited tools available to accurately predict force decrements. This study provides updated endurance time–intensity curves using a large meta-analysis of fatigue data. Specific models derived for five distinct joint regions should further increase prediction accuracy. PMID:20069487

  11. Eliciting mixed emotions: a meta-analysis comparing models, types, and measures

    Science.gov (United States)

    Berrios, Raul; Totterdell, Peter; Kellett, Stephen

    2015-01-01

    The idea that people can experience two oppositely valenced emotions has been controversial ever since early attempts to investigate the construct of mixed emotions. This meta-analysis examined the robustness with which mixed emotions have been elicited experimentally. A systematic literature search identified 63 experimental studies that instigated the experience of mixed emotions. Studies were distinguished according to the structure of the underlying affect model—dimensional or discrete—as well as according to the type of mixed emotions studied (e.g., happy-sad, fearful-happy, positive-negative). The meta-analysis using a random-effects model revealed a moderate to high effect size for the elicitation of mixed emotions (dIG+ = 0.77), which remained consistent regardless of the structure of the affect model, and across different types of mixed emotions. Several methodological and design moderators were tested. Studies using the minimum index (i.e., the minimum value between a pair of opposite valenced affects) resulted in smaller effect sizes, whereas subjective measures of mixed emotions increased the effect sizes. The presence of more women in the samples was also associated with larger effect sizes. The current study indicates that mixed emotions are a robust, measurable and non-artifactual experience. The results are discussed in terms of the implications for an affect system that has greater versatility and flexibility than previously thought. PMID:25926805

  12. Reasoned versus reactive prediction of behaviour: a meta-analysis of the prototype willingness model.

    Science.gov (United States)

    Todd, Jemma; Kothe, Emily; Mullan, Barbara; Monds, Lauren

    2016-01-01

    The prototype willingness model (PWM) was designed to extend expectancy-value models of health behaviour by also including a heuristic, or social reactive pathway, to better explain health-risk behaviours in adolescents and young adults. The pathway includes prototype, i.e., images of a typical person who engages in a behaviour, and willingness to engage in behaviour. The current study describes a meta-analysis of predictive research using the PWM and explores the role of the heuristic pathway and intentions in predicting behaviour. Eighty-one studies met inclusion criteria. Overall, the PWM was supported and explained 20.5% of the variance in behaviour. Willingness explained 4.9% of the variance in behaviour over and above intention, although intention tended to be more strongly related to behaviour than was willingness. The strength of the PWM relationships tended to vary according to the behaviour being tested, with alcohol consumption being the behaviour best explained. Age was also an important moderator, and, as expected, PWM behaviour was best accounted for within adolescent samples. Results were heterogeneous even after moderators were taken into consideration. This meta-analysis provides support for the PWM and may be used to inform future interventions that can be tailored for at-risk populations.

  13. The Five-Factor Model personality traits in schizophrenia: A meta-analysis.

    Science.gov (United States)

    Ohi, Kazutaka; Shimada, Takamitsu; Nitta, Yusuke; Kihara, Hiroaki; Okubo, Hiroaki; Uehara, Takashi; Kawasaki, Yasuhiro

    2016-06-30

    Personality is one of important factors in the pathogenesis of schizophrenia because it affects patients' symptoms, cognition and social functioning. Several studies have reported specific personality traits in patients with schizophrenia compared with healthy subjects. However, the results were inconsistent among studies. The NEO Five-Factor Inventory (NEO-FFI) measures five personality traits: Neuroticism (N), Extraversion (E), Openness (O), Agreeableness (A) and Conscientiousness (C). Here, we performed a meta-analysis of these personality traits assessed by the NEO-FFI in 460 patients with schizophrenia and 486 healthy subjects from the published literature and investigated possible associations between schizophrenia and these traits. There was no publication bias for any traits. Because we found evidence of significant heterogeneity in all traits among the studies, we applied a random-effect model to perform the meta-analysis. Patients with schizophrenia showed a higher score for N and lower scores for E, O, A and C compared with healthy subjects. The effect sizes of these personality traits ranged from moderate to large. These differences were not affected by possible moderator factors, such as gender distribution and mean age in each study, expect for gender effect for A. These findings suggest that patients with schizophrenia have a different personality profile compared with healthy subjects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. A meta-analysis of motivational interviewing process: Technical, relational, and conditional process models of change.

    Science.gov (United States)

    Magill, Molly; Apodaca, Timothy R; Borsari, Brian; Gaume, Jacques; Hoadley, Ariel; Gordon, Rebecca E F; Tonigan, J Scott; Moyers, Theresa

    2018-02-01

    In the present meta-analysis, we test the technical and relational hypotheses of Motivational Interviewing (MI) efficacy. We also propose an a priori conditional process model where heterogeneity of technical path effect sizes should be explained by interpersonal/relational (i.e., empathy, MI Spirit) and intrapersonal (i.e., client treatment seeking status) moderators. A systematic review identified k = 58 reports, describing 36 primary studies and 40 effect sizes (N = 3,025 participants). Statistical methods calculated the inverse variance-weighted pooled correlation coefficient for the therapist to client and the client to outcome paths across multiple target behaviors (i.e., alcohol use, other drug use, other behavior change). Therapist MI-consistent skills were correlated with more client change talk (r = .55, p technical hypothesis was supported. Specifically, proportion MI consistency was related to higher proportion change talk (r = .11, p = .004) and higher proportion change talk was related to reductions in risk behavior at follow up (r = -.16, p technical hypothesis path effect sizes was partially explained by inter- and intrapersonal moderators. This meta-analysis provides additional support for the technical hypothesis of MI efficacy; future research on the relational hypothesis should occur in the field rather than in the context of clinical trials. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  15. Node-Splitting Generalized Linear Mixed Models for Evaluation of Inconsistency in Network Meta-Analysis.

    Science.gov (United States)

    Yu-Kang, Tu

    2016-12-01

    Network meta-analysis for multiple treatment comparisons has been a major development in evidence synthesis methodology. The validity of a network meta-analysis, however, can be threatened by inconsistency in evidence within the network. One particular issue of inconsistency is how to directly evaluate the inconsistency between direct and indirect evidence with regard to the effects difference between two treatments. A Bayesian node-splitting model was first proposed and a similar frequentist side-splitting model has been put forward recently. Yet, assigning the inconsistency parameter to one or the other of the two treatments or splitting the parameter symmetrically between the two treatments can yield different results when multi-arm trials are involved in the evaluation. We aimed to show that a side-splitting model can be viewed as a special case of design-by-treatment interaction model, and different parameterizations correspond to different design-by-treatment interactions. We demonstrated how to evaluate the side-splitting model using the arm-based generalized linear mixed model, and an example data set was used to compare results from the arm-based models with those from the contrast-based models. The three parameterizations of side-splitting make slightly different assumptions: the symmetrical method assumes that both treatments in a treatment contrast contribute to inconsistency between direct and indirect evidence, whereas the other two parameterizations assume that only one of the two treatments contributes to this inconsistency. With this understanding in mind, meta-analysts can then make a choice about how to implement the side-splitting method for their analysis. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  16. Bayesian models and meta analysis for multiple tissue gene expression data following corticosteroid administration

    Directory of Open Access Journals (Sweden)

    Kelemen Arpad

    2008-08-01

    Full Text Available Abstract Background This paper addresses key biological problems and statistical issues in the analysis of large gene expression data sets that describe systemic temporal response cascades to therapeutic doses in multiple tissues such as liver, skeletal muscle, and kidney from the same animals. Affymetrix time course gene expression data U34A are obtained from three different tissues including kidney, liver and muscle. Our goal is not only to find the concordance of gene in different tissues, identify the common differentially expressed genes over time and also examine the reproducibility of the findings by integrating the results through meta analysis from multiple tissues in order to gain a significant increase in the power of detecting differentially expressed genes over time and to find the differential differences of three tissues responding to the drug. Results and conclusion Bayesian categorical model for estimating the proportion of the 'call' are used for pre-screening genes. Hierarchical Bayesian Mixture Model is further developed for the identifications of differentially expressed genes across time and dynamic clusters. Deviance information criterion is applied to determine the number of components for model comparisons and selections. Bayesian mixture model produces the gene-specific posterior probability of differential/non-differential expression and the 95% credible interval, which is the basis for our further Bayesian meta-inference. Meta-analysis is performed in order to identify commonly expressed genes from multiple tissues that may serve as ideal targets for novel treatment strategies and to integrate the results across separate studies. We have found the common expressed genes in the three tissues. However, the up/down/no regulations of these common genes are different at different time points. Moreover, the most differentially expressed genes were found in the liver, then in kidney, and then in muscle.

  17. Cycling empirical antibiotic therapy in hospitals: meta-analysis and models.

    Directory of Open Access Journals (Sweden)

    Pia Abel zur Wiesch

    2014-06-01

    Full Text Available The rise of resistance together with the shortage of new broad-spectrum antibiotics underlines the urgency of optimizing the use of available drugs to minimize disease burden. Theoretical studies suggest that coordinating empirical usage of antibiotics in a hospital ward can contain the spread of resistance. However, theoretical and clinical studies came to different conclusions regarding the usefulness of rotating first-line therapy (cycling. Here, we performed a quantitative pathogen-specific meta-analysis of clinical studies comparing cycling to standard practice. We searched PubMed and Google Scholar and identified 46 clinical studies addressing the effect of cycling on nosocomial infections, of which 11 met our selection criteria. We employed a method for multivariate meta-analysis using incidence rates as endpoints and find that cycling reduced the incidence rate/1000 patient days of both total infections by 4.95 [9.43-0.48] and resistant infections by 7.2 [14.00-0.44]. This positive effect was observed in most pathogens despite a large variance between individual species. Our findings remain robust in uni- and multivariate metaregressions. We used theoretical models that reflect various infections and hospital settings to compare cycling to random assignment to different drugs (mixing. We make the realistic assumption that therapy is changed when first line treatment is ineffective, which we call "adjustable cycling/mixing". In concordance with earlier theoretical studies, we find that in strict regimens, cycling is detrimental. However, in adjustable regimens single resistance is suppressed and cycling is successful in most settings. Both a meta-regression and our theoretical model indicate that "adjustable cycling" is especially useful to suppress emergence of multiple resistance. While our model predicts that cycling periods of one month perform well, we expect that too long cycling periods are detrimental. Our results suggest that

  18. Video Game Acceptance: A Meta-Analysis of the Extended Technology Acceptance Model.

    Science.gov (United States)

    Wang, Xiaohui; Goh, Dion Hoe-Lian

    2017-11-01

    The current study systematically reviews and summarizes the existing literature of game acceptance, identifies the core determinants, and evaluates the strength of the relationships in the extended technology acceptance model. Moreover, this study segments video games into two categories: hedonic and utilitarian and examines player acceptance of these two types separately. Through a meta-analysis of 50 articles, we find that perceived ease of use (PEOU), perceived usefulness (PU), and perceived enjoyment (PE) significantly associate with attitude and behavioral intention. PE is the dominant predictor of hedonic game acceptance, while PEOU and PU are the main determinants of utilitarian game acceptance. Furthermore, we find that respondent type and game platform are significant moderators. Findings of this study provide critical insights into the phenomenon of game acceptance and suggest directions for future research.

  19. Assessing Independent Variables Used in Econometric Modeling Forest Land Use or Land Cover Change: A Meta-Analysis

    Science.gov (United States)

    J Jeuck; F. Cubbage; R. Abt; R. Bardon; J. McCarter; J. Coulston; M. Renkow

    2014-01-01

    : We conducted a meta-analysis on 64 econometric models from 47 studies predicting forestland conversion to agriculture (F2A), forestland to development (F2D), forestland to non-forested (F2NF) and undeveloped (including forestland) to developed (U2D) land. Over 250 independent econometric variables were identified from 21 F2A models, 21 F2D models, 12 F2NF models, and...

  20. The Trans-Contextual Model of Autonomous Motivation in Education: Conceptual and Empirical Issues and Meta-Analysis.

    Science.gov (United States)

    Hagger, Martin S; Chatzisarantis, Nikos L D

    2016-06-01

    The trans-contextual model outlines the processes by which autonomous motivation toward activities in a physical education context predicts autonomous motivation toward physical activity outside of school, and beliefs about, intentions toward, and actual engagement in, out-of-school physical activity. In the present article, we clarify the fundamental propositions of the model and resolve some outstanding conceptual issues, including its generalizability across multiple educational domains, criteria for its rejection or failed replication, the role of belief-based antecedents of intentions, and the causal ordering of its constructs. We also evaluate the consistency of model relationships in previous tests of the model using path-analytic meta-analysis. The analysis supported model hypotheses but identified substantial heterogeneity in the hypothesized relationships across studies unattributed to sampling and measurement error. Based on our meta-analysis, future research needs to provide further replications of the model in diverse educational settings beyond physical education and test model hypotheses using experimental methods.

  1. A regulation probability model-based meta-analysis of multiple transcriptomics data sets for cancer biomarker identification.

    Science.gov (United States)

    Xie, Xin-Ping; Xie, Yu-Feng; Wang, Hong-Qiang

    2017-08-23

    Large-scale accumulation of omics data poses a pressing challenge of integrative analysis of multiple data sets in bioinformatics. An open question of such integrative analysis is how to pinpoint consistent but subtle gene activity patterns across studies. Study heterogeneity needs to be addressed carefully for this goal. This paper proposes a regulation probability model-based meta-analysis, jGRP, for identifying differentially expressed genes (DEGs). The method integrates multiple transcriptomics data sets in a gene regulatory space instead of in a gene expression space, which makes it easy to capture and manage data heterogeneity across studies from different laboratories or platforms. Specifically, we transform gene expression profiles into a united gene regulation profile across studies by mathematically defining two gene regulation events between two conditions and estimating their occurring probabilities in a sample. Finally, a novel differential expression statistic is established based on the gene regulation profiles, realizing accurate and flexible identification of DEGs in gene regulation space. We evaluated the proposed method on simulation data and real-world cancer datasets and showed the effectiveness and efficiency of jGRP in identifying DEGs identification in the context of meta-analysis. Data heterogeneity largely influences the performance of meta-analysis of DEGs identification. Existing different meta-analysis methods were revealed to exhibit very different degrees of sensitivity to study heterogeneity. The proposed method, jGRP, can be a standalone tool due to its united framework and controllable way to deal with study heterogeneity.

  2. A unification of models for meta-analysis of diagnostic accuracy studies without a gold standard.

    Science.gov (United States)

    Liu, Yulun; Chen, Yong; Chu, Haitao

    2015-06-01

    Several statistical methods for meta-analysis of diagnostic accuracy studies have been discussed in the presence of a gold standard. However, in practice, the selected reference test may be imperfect due to measurement error, non-existence, invasive nature, or expensive cost of a gold standard. It has been suggested that treating an imperfect reference test as a gold standard can lead to substantial bias in the estimation of diagnostic test accuracy. Recently, two models have been proposed to account for imperfect reference test, namely, a multivariate generalized linear mixed model (MGLMM) and a hierarchical summary receiver operating characteristic (HSROC) model. Both models are very flexible in accounting for heterogeneity in accuracies of tests across studies as well as the dependence between tests. In this article, we show that these two models, although with different formulations, are closely related and are equivalent in the absence of study-level covariates. Furthermore, we provide the exact relations between the parameters of these two models and assumptions under which two models can be reduced to equivalent submodels. On the other hand, we show that some submodels of the MGLMM do not have corresponding equivalent submodels of the HSROC model, and vice versa. With three real examples, we illustrate the cases when fitting the MGLMM and HSROC models leads to equivalent submodels and hence identical inference, and the cases when the inferences from two models are slightly different. Our results generalize the important relations between the bivariate generalized linear mixed model and HSROC model when the reference test is a gold standard. © 2014, The International Biometric Society.

  3. Efficacy of the superoxide dismutase mimetic tempol in animal hypertension models: a meta-analysis.

    Science.gov (United States)

    Dornas, Waleska C; Silva, Maísa; Tavares, Ricardo; de Lima, Wanderson G; dos Santos, Rinaldo C; Pedrosa, Maria L; Silva, Marcelo E

    2015-01-01

    Considering the growing body of evidence that indicates the contribution of superoxide anions (O2) and other reactive oxygen species (ROS) to the development of hypertension, we assessed whether animal models of hypertension have a benefic effect with tempol, a superoxide dismutase mimetic, to help augment the design of future studies. Studies published between July 1998 and December 2012 on blood pressure (BP) in different hypertensive models were obtained after an electronic and manual search of PubMed. In-depth analyses of the methodological quality of the studies and the mean arterial pressure (MAP) changes after treatment with tempol were performed, as well as the subgroup analyses on the route of tempol delivery. Out of the 144 identified studies, 28 were included after screening. The data showed that tempol reduced MAP by computing the standardized mean difference with the value of 4.622 (95% confidence interval 3.24-5.99). The quality of studies included in the meta-analysis was category II; however, omission of details in the trials might have biased the results. There was substantial heterogeneity in the results with an I of 94.45%, which persisted after stratifying for the route of tempol delivery. In conclusion, this analysis shows that antioxidant treatment with tempol can reduce BP, suggesting that ROS plays a role in the pathogenesis of increased BP in the hypertension models used in the current research practice.

  4. Modelling multiple thresholds in meta-analysis of diagnostic test accuracy studies

    Directory of Open Access Journals (Sweden)

    Susanne Steinhauser

    2016-08-01

    Full Text Available Abstract Background In meta-analyses of diagnostic test accuracy, routinely only one pair of sensitivity and specificity per study is used. However, for tests based on a biomarker or a questionnaire often more than one threshold and the corresponding values of true positives, true negatives, false positives and false negatives are known. Methods We present a new meta-analysis approach using this additional information. It is based on the idea of estimating the distribution functions of the underlying biomarker or questionnaire within the non-diseased and diseased individuals. Assuming a normal or logistic distribution, we estimate the distribution parameters in both groups applying a linear mixed effects model to the transformed data. The model accounts for across-study heterogeneity and dependence of sensitivity and specificity. In addition, a simulation study is presented. Results We obtain a summary receiver operating characteristic (SROC curve as well as the pooled sensitivity and specificity at every specific threshold. Furthermore, the determination of an optimal threshold across studies is possible through maximization of the Youden index. We demonstrate our approach using two meta-analyses of B type natriuretic peptide in heart failure and procalcitonin as a marker for sepsis. Conclusions Our approach uses all the available information and results in an estimation not only of the performance of the biomarker but also of the threshold at which the optimal performance can be expected.

  5. GMCM: Unsupervised Clustering and Meta-Analysis Using Gaussian Mixture Copula Models

    Directory of Open Access Journals (Sweden)

    Anders Ellern Bilgrau

    2016-04-01

    Full Text Available Methods for clustering in unsupervised learning are an important part of the statistical toolbox in numerous scientific disciplines. Tewari, Giering, and Raghunathan (2011 proposed to use so-called Gaussian mixture copula models (GMCM for general unsupervised learning based on clustering. Li, Brown, Huang, and Bickel (2011 independently discussed a special case of these GMCMs as a novel approach to meta-analysis in highdimensional settings. GMCMs have attractive properties which make them highly flexible and therefore interesting alternatives to other well-established methods. However, parameter estimation is hard because of intrinsic identifiability issues and intractable likelihood functions. Both aforementioned papers discuss similar expectation-maximization-like algorithms as their pseudo maximum likelihood estimation procedure. We present and discuss an improved implementation in R of both classes of GMCMs along with various alternative optimization routines to the EM algorithm. The software is freely available in the R package GMCM. The implementation is fast, general, and optimized for very large numbers of observations. We demonstrate the use of package GMCM through different applications.

  6. Enamel matrix derivative for replanted teeth in animal models: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Sahng G. Kim

    2013-11-01

    Full Text Available Objectives To investigate the effect of enamel matrix derivative (EMD on periodontal healing of replanted teeth in animal models. Materials and Methods The authors searched MEDLINE, PubMed, EMBASE, Cochrane Library, Web of Knowledge and Scopus for articles published up to Oct 2012. Animal studies in which EMD was applied in transplanted or replanted teeth with adequate controls and histological data were considered. Normal periodontal healing or root resorption determined by histology after EMD was applied in replanted teeth with adequate controls was used as outcome measures. The following search strategy was used: ('Emdogain' OR 'enamel matrix proteins' OR 'enamel matrix derivative' AND ('avulsion' OR 'transplantion' OR 'autotransplantation' OR 'replantation'. Results Six animal studies were included in the final review. There was great heterogeneity in study design among included studies. Two studies with similar study designs were identified and analyzed by a meta-analysis. The pooled estimates showed a significantly higher normal healing and surface resorption and significantly less inflammatory and replacement resorption in EMD-treated groups compared with non-EMD-treated groups. Conclusions With the limitations of this systematic review, the use of EMD led to greater normal periodontal healing and surface root resorption and less inflammatory and replacement root resorption in the presence of periodontal ligaments. However, no definite conclusion could be drawn with regard to the effect of EMD on periodontal healing and root resorption when no periodontal ligaments exist.

  7. Meta-Analysis of Effect Sizes Reported at Multiple Time Points Using General Linear Mixed Model

    Science.gov (United States)

    Musekiwa, Alfred; Manda, Samuel O. M.; Mwambi, Henry G.; Chen, Ding-Geng

    2016-01-01

    Meta-analysis of longitudinal studies combines effect sizes measured at pre-determined time points. The most common approach involves performing separate univariate meta-analyses at individual time points. This simplistic approach ignores dependence between longitudinal effect sizes, which might result in less precise parameter estimates. In this paper, we show how to conduct a meta-analysis of longitudinal effect sizes where we contrast different covariance structures for dependence between effect sizes, both within and between studies. We propose new combinations of covariance structures for the dependence between effect size and utilize a practical example involving meta-analysis of 17 trials comparing postoperative treatments for a type of cancer, where survival is measured at 6, 12, 18 and 24 months post randomization. Although the results from this particular data set show the benefit of accounting for within-study serial correlation between effect sizes, simulations are required to confirm these results. PMID:27798661

  8. Dialectical Behavior Therapy for Borderline Personality Disorder: A Meta-Analysis Using Mixed-Effects Modeling

    Science.gov (United States)

    Kliem, Soren; Kroger, Christoph; Kosfelder, Joachim

    2010-01-01

    Objective: At present, the most frequently investigated psychosocial intervention for borderline personality disorder (BPD) is dialectical behavior therapy (DBT). We conducted a meta-analysis to examine the efficacy and long-term effectiveness of DBT. Method: Systematic bibliographic research was undertaken to find relevant literature from online…

  9. Case-fatality of COPD exacerbations: a meta-analysis and statistical modeling approach

    DEFF Research Database (Denmark)

    Hoogendoorn, M; Hoogenveen, R T; Rutten-van Mölken, M P

    2010-01-01

    %-confidence interval. The meta-analysis based on six studies that fulfilled the inclusion criteria resulted in a weighted average case-fatality rate of 15.6% (95%CI:10.9%-20.3%), ranging from 11.4% to 19.0% for the individual studies. A severe COPD exacerbation requiring hospitalization not only results...

  10. Dialectical behavior therapy for borderline personality disorder: a meta-analysis using mixed-effects modeling.

    Science.gov (United States)

    Kliem, Sören; Kröger, Christoph; Kosfelder, Joachim

    2010-12-01

    At present, the most frequently investigated psychosocial intervention for borderline personality disorder (BPD) is dialectical behavior therapy (DBT). We conducted a meta-analysis to examine the efficacy and long-term effectiveness of DBT. Systematic bibliographic research was undertaken to find relevant literature from online databases (PubMed, PsycINFO, PsychSpider, Medline). We excluded studies in which patients with diagnoses other than BPD were treated, the treatment did not comprise all components specified in the DBT manual or in the suggestions for inpatient DBT programs, patients failed to be diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, and the intervention group comprised fewer than 10 patients. Using a mixed-effect hierarchical modeling approach, we calculated global effect sizes and effect sizes for suicidal and self-injurious behaviors. Calculations of postintervention global effect sizes were based on 16 studies. Of these, 8 were randomized controlled trials (RCTs), and 8 were neither randomized nor controlled (nRCT). The dropout rate was 27.3% pre- to posttreatment. A moderate global effect and a moderate effect size for suicidal and self-injurious behaviors were found, when including a moderator for RCTs with borderline-specific treatments. There was no evidence for the influence of other moderators (e.g., quality of studies, setting, duration of intervention). A small impairment was shown from posttreatment to follow-up, including 5 RCTs only. Future research should compare DBT with other active borderline-specific treatments that have also demonstrated their efficacy using several long-term follow-up assessment points. (c) 2010 APA, all rights reserved.

  11. Meta-analysis for diagnostic accuracy studies: a new statistical model using beta-binomial distributions and bivariate copulas.

    Science.gov (United States)

    Kuss, Oliver; Hoyer, Annika; Solms, Alexander

    2014-01-15

    There are still challenges when meta-analyzing data from studies on diagnostic accuracy. This is mainly due to the bivariate nature of the response where information on sensitivity and specificity must be summarized while accounting for their correlation within a single trial. In this paper, we propose a new statistical model for the meta-analysis for diagnostic accuracy studies. This model uses beta-binomial distributions for the marginal numbers of true positives and true negatives and links these margins by a bivariate copula distribution. The new model comes with all the features of the current standard model, a bivariate logistic regression model with random effects, but has the additional advantages of a closed likelihood function and a larger flexibility for the correlation structure of sensitivity and specificity. In a simulation study, which compares three copula models and two implementations of the standard model, the Plackett and the Gauss copula do rarely perform worse but frequently better than the standard model. We use an example from a meta-analysis to judge the diagnostic accuracy of telomerase (a urinary tumor marker) for the diagnosis of primary bladder cancer for illustration. Copyright © 2013 John Wiley & Sons, Ltd.

  12. Alveolar bone tissue engineering in critical-size defects of experimental animal models: a systematic review and meta-analysis.

    Science.gov (United States)

    Shanbhag, Siddharth; Pandis, Nikolaos; Mustafa, Kamal; Nyengaard, Jens R; Stavropoulos, Andreas

    2017-10-01

    Regeneration of large, 'critical-size' bone defects remains a clinical challenge. Bone tissue engineering (BTE) is emerging as a promising alternative to autogenous, allogeneic and biomaterial-based bone grafting. The objective of this systematic review was to answer the focused question: in animal models, do cell-based BTE strategies enhance regeneration in alveolar bone critical-size defects (CSDs), compared with grafting with only biomaterial scaffolds or autogenous bone? Following PRISMA guidelines, electronic databases were searched for controlled animal studies reporting maxillary or mandibular CSD and implantation of mesenchymal stem cells (MSCs) or osteoblasts (OBs) seeded on biomaterial scaffolds. A random effects meta-analysis was performed for the outcome histomorphometric new bone formation (%NBF). Thirty-six studies were included that reported on large- (monkeys, dogs, sheep, minipigs) and small-animal (rabbits, rats) models. On average, studies presented with an unclear-to-high risk of bias and short observation times. In most studies, MSCs or OBs were used in combination with alloplastic mineral-phase scaffolds. In five studies, cells were modified by ex vivo gene transfer of bone morphogenetic proteins (BMPs). The meta-analysis indicated statistically significant benefits in favour of: (1) cell-loaded vs. cell-free scaffolds [weighted mean difference (WMD) 15.59-49.15% and 8.60-13.85% NBF in large- and small-animal models, respectively]; and (2) BMP-gene-modified vs. unmodified cells (WMD 10.06-20.83% NBF in small-animal models). Results of cell-loaded scaffolds vs. autogenous bone were inconclusive. Overall, heterogeneity in the meta-analysis was high (I 2  > 90%). In summary, alveolar bone regeneration is enhanced by addition of osteogenic cells to biomaterial scaffolds. The direction and estimates of treatment effect are useful to predict therapeutic efficacy and guide future clinical trials of BTE. Copyright © 2016 John Wiley & Sons, Ltd

  13. Analytic models of plausible gravitational lens potentials

    International Nuclear Information System (INIS)

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2009-01-01

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sérsic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sérsic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses

  14. Anti-tumor effects of metformin in animal models of hepatocellular carcinoma: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Juan Li

    Full Text Available Several studies have reported that metformin can reduce the risk of hepatocellular carcinoma (HCC in diabetes patients. However, the direct anti-HCC effects of metformin have hardly been studied in patients, but have been extensively investigated in animal models of HCC. We therefore performed a systematic review and meta-analysis of animal studies evaluating the effects of metformin on HCC.We collected the relevant studies by searching EMBASE, Medline (OvidSP, Web of Science, Scopus, PubMed Publisher, and Google Scholar. Studies were included according to the following inclusion criteria: HCC, animal study, and metformin intervention. Study quality was assessed using SYRCLE's risk of bias tool. A meta-analysis was performed for the outcome measures: tumor growth (tumor volume, weight and size, tumor number and incidence.The search resulted in 573 references, of which 13 could be included in the review and 12 included in the meta-analysis. The study characteristics of the included studies varied considerably. Two studies used rats, while the others used mice. Only one study used female animals, nine used male, and three studies didn't mention the gender of animals in their experiments. The quality of the included studies was low to moderate based on the assessment of their risk of bias. The meta-analysis showed that metformin significantly inhibited the growth of HCC tumour (SMD -2.20[-2.96,-1.43]; n=16, but no significant effect on the number of tumors (SMD-1.05[-2.13,0.03]; n=5 or the incidence of HCC was observed (RR 0.62[0.33,1.16]; n=6. To investigate the potential sources of significant heterogeneities found in outcome of tumor growth (I2=81%, subgroup analyses of scales of growth measures and of types of animal models used were performed.Metformin appears to have a direct anti-HCC effect in animal models. Although the intrinsic limitations of animal studies, this systematic review could provide an important reference for future

  15. Why Do Lie-Catchers Fail? A Lens Model Meta-Analysis of Human Lie Judgments

    Science.gov (United States)

    Hartwig, Maria; Bond, Charles F., Jr.

    2011-01-01

    Decades of research has shown that people are poor at detecting lies. Two explanations for this finding have been proposed. First, it has been suggested that lie detection is inaccurate because people rely on invalid cues when judging deception. Second, it has been suggested that lack of valid cues to deception limits accuracy. A series of 4…

  16. Atorvastatin treatment improves effects of implanted mesenchymal stem cells: meta-analysis of animal models with acute myocardial infarction.

    Science.gov (United States)

    Dai, Guo; Xu, Qing; Luo, Rong; Gao, Jianfang; Chen, Hui; Deng, Yun; Li, Yongqing; Wang, Yuequn; Yuan, Wuzhou; Wu, Xiushan

    2015-12-14

    Previous studies reported that Atorvastatin (ATOR) can improve the efficacy of Mesenchymal stem cells (MSCs) transplantation after acute myocardial infarction (AMI). However, the results of those studies were inconsistent. To clarify the beneficial effects of atorvastatin added to the cell therapy with MSCs in animal model of acute myocardial infarction (AMI), we performed a systematic review and meta-analysis of case-control studies. Searches were performed using the PubMed database, the Excerpta Medica Database (Embase), the Science Citation Index, the China National Knowledge Information database, the Wanfang database, and the Chinese Scientific and Technological Journal Database (VIP database). The search term included "Atorvastatin (or Ator)", "Mesenchymal Stem Cells (or Mesenchymal Stem Cell or MSC or MSCs)" and "Acute Myocardial Infarction (or Myocardial Infarction or AMI or MI)". The endpoints were the left ventricular ejection fraction (LVEF) in animal model with AMI. In total, 5 studies were included in the meta-analysis. Pooled analysis indicated a significant LVEF difference at 4 weeks follow-up between MSCs + ATOR combine group and MSCs alone group (95 % CI, 9.09-13.62 %; P 0.05) and inconsistency (I(2): 22 %). Atorvastatin can enhance the existing effects of MSCs transplantation, and this combinational therapy is a superior cell/pharmacological therapeutic approach that merits future preclinical and clinical studies.

  17. Meta-analysis approach as a gene selection method in class prediction: does it improve model performance? A case study in acute myeloid leukemia.

    Science.gov (United States)

    Novianti, Putri W; Jong, Victor L; Roes, Kit C B; Eijkemans, Marinus J C

    2017-04-11

    Aggregating gene expression data across experiments via meta-analysis is expected to increase the precision of the effect estimates and to increase the statistical power to detect a certain fold change. This study evaluates the potential benefit of using a meta-analysis approach as a gene selection method prior to predictive modeling in gene expression data. Six raw datasets from different gene expression experiments in acute myeloid leukemia (AML) and 11 different classification methods were used to build classification models to classify samples as either AML or healthy control. First, the classification models were trained on gene expression data from single experiments using conventional supervised variable selection and externally validated with the other five gene expression datasets (referred to as the individual-classification approach). Next, gene selection was performed through meta-analysis on four datasets, and predictive models were trained with the selected genes on the fifth dataset and validated on the sixth dataset. For some datasets, gene selection through meta-analysis helped classification models to achieve higher performance as compared to predictive modeling based on a single dataset; but for others, there was no major improvement. Synthetic datasets were generated from nine simulation scenarios. The effect of sample size, fold change and pairwise correlation between differentially expressed (DE) genes on the difference between MA- and individual-classification model was evaluated. The fold change and pairwise correlation significantly contributed to the difference in performance between the two methods. The gene selection via meta-analysis approach was more effective when it was conducted using a set of data with low fold change and high pairwise correlation on the DE genes. Gene selection through meta-analysis on previously published studies potentially improves the performance of a predictive model on a given gene expression data.

  18. Population-level impact, herd immunity, and elimination after human papillomavirus vaccination: a systematic review and meta-analysis of predictions from transmission-dynamic models.

    NARCIS (Netherlands)

    Brisson, Marc; Bénard, Élodie; Drolet, Mélanie; Bogaards, Johannes A; Baussano, Iacopo; Vänskä, Simopekka; Jit, Mark; Boily, Marie-Claude; Smith, Megan A; Berkhof, Johannes; Canfell, Karen; Chesson, Harrell W; Burger, Emily A; Choi, Yoon H; De Blasio, Birgitte Freiesleben; De Vlas, Sake J; Guzzetta, Giorgio; Hontelez, Jan A C; Horn, Johannes; Jepsen, Martin R; Kim, Jane J; Lazzarato, Fulvio; Matthijsse, Suzette M; Mikolajczyk, Rafael; Pavelyev, Andrew; Pillsbury, Matthew; Shafer, Leigh Anne; Tully, Stephen P; Turner, Hugo C; Usher, Cara; Walsh, Cathal

    2016-01-01

    Modelling studies have been widely used to inform human papillomavirus (HPV) vaccination policy decisions; however, many models exist and it is not known whether they produce consistent predictions of population-level effectiveness and herd effects. We did a systematic review and meta-analysis of

  19. Two families of astrophysical diverging lens models

    Science.gov (United States)

    Er, Xinzhong; Rogers, Adam

    2018-03-01

    In the standard gravitational lensing scenario, rays from a background source are bent in the direction of a foreground lensing mass distribution. Diverging lens behaviour produces deflections in the opposite sense to gravitational lensing, and is also of astrophysical interest. In fact, diverging lensing due to compact distributions of plasma has been proposed as an explanation for the extreme scattering events that produce frequency-dependent dimming of extragalactic radio sources, and may also be related to the refractive radio wave phenomena observed to affect the flux density of pulsars. In this work we study the behaviour of two families of astrophysical diverging lenses in the geometric optics limit, the power law, and the exponential plasma lenses. Generally, the members of these model families show distinct behaviour in terms of image formation and magnification, however the inclusion of a finite core for certain power-law lenses can produce a caustic and critical curve morphology that is similar to the well-studied Gaussian plasma lens. Both model families can produce dual radial critical curves, a novel distinction from the tangential distortion usually produced by gravitational (converging) lenses. The deflection angle and magnification of a plasma lens vary with the observational frequency, producing wavelength-dependent magnifications that alter the amplitudes and the shape of the light curves. Thus, multiwavelength observations can be used to physically constrain the distribution of the electron density in such lenses.

  20. Longitudinal Meta-analysis

    NARCIS (Netherlands)

    Hox, J.J.; Maas, C.J.M.; Lensvelt-Mulders, G.J.L.M.

    2004-01-01

    The goal of meta-analysis is to integrate the research results of a number of studies on a specific topic. Characteristic for meta-analysis is that in general only the summary statistics of the studies are used and not the original data. When the published research results to be integrated

  1. A predictive model for canine dilated cardiomyopathy—a meta-analysis of Doberman Pinscher data

    Directory of Open Access Journals (Sweden)

    Siobhan Simpson

    2015-03-01

    Full Text Available Dilated cardiomyopathy is a prevalent and often fatal disease in humans and dogs. Indeed dilated cardiomyopathy is the third most common form of cardiac disease in humans, reported to affect approximately 36 individuals per 100,000 individuals. In dogs, dilated cardiomyopathy is the second most common cardiac disease and is most prevalent in the Irish Wolfhound, Doberman Pinscher and Newfoundland breeds. Dilated cardiomyopathy is characterised by ventricular chamber enlargement and systolic dysfunction which often leads to congestive heart failure. Although multiple human loci have been implicated in the pathogenesis of dilated cardiomyopathy, the identified variants are typically associated with rare monogenic forms of dilated cardiomyopathy. The potential for multigenic interactions contributing to human dilated cardiomyopathy remains poorly understood. Consistent with this, several known human dilated cardiomyopathy loci have been excluded as common causes of canine dilated cardiomyopathy, although canine dilated cardiomyopathy resembles the human disease functionally. This suggests additional genetic factors contribute to the dilated cardiomyopathy phenotype.This study represents a meta-analysis of available canine dilated cardiomyopathy genetic datasets with the goal of determining potential multigenic interactions relating the sex chromosome genotype (XX vs. XY with known dilated cardiomyopathy associated loci on chromosome 5 and the PDK4 gene in the incidence and progression of dilated cardiomyopathy. The results show an interaction between known canine dilated cardiomyopathy loci and an unknown X-linked locus. Our study is the first to test a multigenic contribution to dilated cardiomyopathy and suggest a genetic basis for the known sex-disparity in dilated cardiomyopathy outcomes.

  2. Meta-analysis of determinants for pet ownership in 12 European birth cohorts on asthma and allergies: a GA2LEN initiative

    DEFF Research Database (Denmark)

    Eller, E; Roll, S; Chen, C-M

    2008-01-01

    with and without allergies. METHODS: Within the EU-funded network of excellence GA(2)LEN, we performed meta-analyses with data from 12 ongoing European birth cohort studies on asthma and allergy. Each of the birth cohort studies enrolled between 485 and 4089 children. Pet ownership, allergic status (asthma......, allergic rhinitis, eczema) of parents and siblings, parental education, access to ground floor, and number of people living at home were assessed by questionnaires. RESULTS: Among the 25 056 families from seven European countries cats (14.9%) were more common than dogs (12.0%). Allergic family history......, but not dogs. Convenient ground access significantly increased the odds, whereas crowding at home was not associated with cat or dog ownership. CONCLUSIONS: The chances to own a cat or dog were significantly reduced in allergic families, in parents with a higher educational level, and in homes without...

  3. Accuracy of fish-eye lens models.

    Science.gov (United States)

    Hughes, Ciarán; Denny, Patrick; Jones, Edward; Glavin, Martin

    2010-06-10

    The majority of computer vision applications assumes that the camera adheres to the pinhole camera model. However, most optical systems will introduce undesirable effects. By far, the most evident of these effects is radial lensing, which is particularly noticeable in fish-eye camera systems, where the effect is relatively extreme. Several authors have developed models of fish-eye lenses that can be used to describe the fish-eye displacement. Our aim is to evaluate the accuracy of several of these models. Thus, we present a method by which the lens curve of a fish-eye camera can be extracted using well-founded assumptions and perspective methods. Several of the models from the literature are examined against this empirically derived curve.

  4. Kinetic modelling and meta-analysis of the B. subtilis SigA regulatory network during spore germination and outgrowth.

    Science.gov (United States)

    Ramaniuk, O; Černý, M; Krásný, L; Vohradský, J

    2017-08-01

    This study describes the meta-analysis and kinetic modelling of gene expression control by sigma factor SigA of Bacillus subtilis during germination and outgrowth based on microarray data from 14 time points. The analysis computationally models the direct interaction among SigA, SigA-controlled sigma factor genes (sigM, sigH, sigD, sigX), and their target genes. Of the >800 known genes in the SigA regulon, as extracted from databases, 311 genes were analysed, and 190 were confirmed by the kinetic model as being controlled by SigA. For the remaining genes, alternative regulators satisfying kinetic constraints were suggested. The kinetic analysis suggested another 214 genes as potential SigA targets. The modelling was able to (i) create a particular SigA-controlled gene expression network that is active under the conditions for which the expression time series was obtained, and where SigA is the dominant regulator, (ii) suggest new potential SigA target genes, and (iii) find other possible regulators of a given gene or suggest a new mechanism of its control by identifying a matching profile of unknown regulator(s). Selected predicted regulatory interactions were experimentally tested, thus validating the model. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Evidence synthesis for decision making 2: a generalized linear modeling framework for pairwise and network meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Dias, Sofia; Sutton, Alex J; Ades, A E; Welton, Nicky J

    2013-07-01

    We set out a generalized linear model framework for the synthesis of data from randomized controlled trials. A common model is described, taking the form of a linear regression for both fixed and random effects synthesis, which can be implemented with normal, binomial, Poisson, and multinomial data. The familiar logistic model for meta-analysis with binomial data is a generalized linear model with a logit link function, which is appropriate for probability outcomes. The same linear regression framework can be applied to continuous outcomes, rate models, competing risks, or ordered category outcomes by using other link functions, such as identity, log, complementary log-log, and probit link functions. The common core model for the linear predictor can be applied to pairwise meta-analysis, indirect comparisons, synthesis of multiarm trials, and mixed treatment comparisons, also known as network meta-analysis, without distinction. We take a Bayesian approach to estimation and provide WinBUGS program code for a Bayesian analysis using Markov chain Monte Carlo simulation. An advantage of this approach is that it is straightforward to extend to shared parameter models where different randomized controlled trials report outcomes in different formats but from a common underlying model. Use of the generalized linear model framework allows us to present a unified account of how models can be compared using the deviance information criterion and how goodness of fit can be assessed using the residual deviance. The approach is illustrated through a range of worked examples for commonly encountered evidence formats.

  6. Meta-analysis of determinants for pet ownership in 12 European birth cohorts on asthma and allergies: a GA2LEN initiative.

    Science.gov (United States)

    Eller, E; Roll, S; Chen, C-M; Herbarth, O; Wichmann, H-E; von Berg, A; Krämer, U; Mommers, M; Thijs, C; Wijga, A; Brunekreef, B; Fantini, M P; Bravi, F; Forastiere, F; Porta, D; Sunyer, J; Torrent, M; Høst, A; Halken, S; Lødrup Carlsen, K C; Carlsen, K-H; Wickman, M; Kull, I; Wahn, U; Willich, S N; Lau, S; Keil, T; Heinrich, J

    2008-11-01

    Studies on pet ownership as a risk or protective factor for asthma and allergy show inconsistent results. This may be on account of insufficient adjustment of confounding factors. The objective of this study was to describe determinants of cat and dog ownership in European families with and without allergies. Within the EU-funded network of excellence GA(2)LEN, we performed meta-analyses with data from 12 ongoing European birth cohort studies on asthma and allergy. Each of the birth cohort studies enrolled between 485 and 4089 children. Pet ownership, allergic status (asthma, allergic rhinitis, eczema) of parents and siblings, parental education, access to ground floor, and number of people living at home were assessed by questionnaires. Among the 25 056 families from seven European countries cats (14.9%) were more common than dogs (12.0%). Allergic family history significantly reduced the odds to own a cat (adjusted combined random-effect OR 0.91; 95% CI 0.85-0.99), or dog (0.90; 0.86-0.94). A higher parental educational level had even more pronounced effects on cat (0.84; 0.71-0.98), and dog ownership (0.61; 0.54-0.70). Elder siblings reduced the odds to own cats, but not dogs. Convenient ground access significantly increased the odds, whereas crowding at home was not associated with cat or dog ownership. The chances to own a cat or dog were significantly reduced in allergic families, in parents with a higher educational level, and in homes without convenient ground access. In addition to parental allergies, social and housing factors should be considered as potential confounders in studies on pet exposure and allergic diseases.

  7. Beneficial Effects of Caloric Restriction on Chronic Kidney Disease in Rodent Models: A Meta-Analysis and Systematic Review.

    Directory of Open Access Journals (Sweden)

    Xiao-Meng Xu

    Full Text Available Numerous studies have demonstrated the life-extending effect of caloric restriction. It is generally accepted that caloric restriction has health benefits, such as prolonging lifespan and delaying the onset and progression of CKD in various species, especially in rodent models. Although many studies have tested the efficacy of caloric restriction, no complete quantitative analysis of the potential beneficial effects of reducing caloric intake on the development and progression of CKD has been published.All studies regarding the relationship between caloric restriction and chronic kidney diseases were searched in electronic databases, including PubMed/MEDLINE, EMBASE, Science Citation Index (SCI, OVID evidence-based medicine, Chinese Bio-medical Literature and Chinese science and technology periodicals (CNKI, VIP, and Wan Fang. The pooled odds ratios (OR and 95% confidence intervals (95% CI were calculated by using fixed- or random-effects models.The data from 27 of all the studies mentioned above was used in the Meta analysis. Through the meta-analysis, we found that the parameter of blood urea nitrogen, serum creatinine and urinary protein levels of the AL group was significant higher than that of the CR group, which are 4.11 mg/dl, 0.08mg/dl and 33.20mg/kg/24h, respectively. The incidence of the nephropathy in the caloric restriction (CR group was significantly lower than that in the ad libitum-fed (AL group. We further introduced the subgroup analysis and found that the effect of caloric restriction on the occurrence of kidney disease was only significant with prolonged intervention; the beneficial effects of CR on the 60%-caloric-restriction group were greater than on the less-than-60%-caloric-restriction group, and caloric restriction did not show obvious protective effects in genetically modified strains. Moreover, survival rate of the caloric restriction group is much higher than that of the ad libitum-fed (AL group.Our findings

  8. Efficacy of the theory of planned behavior in predicting breastfeeding: Meta-analysis and structural equation modeling.

    Science.gov (United States)

    Guo, J L; Wang, T F; Liao, J Y; Huang, C M

    2016-02-01

    This study assessed the applicability and efficacy of the theory of planned behavior (TPB) in predicting breastfeeding. The TPB assumes a rational approach for engaging in various behaviors, and has been used extensively for explaining health behavior. However, most studies have tested the effectiveness of TPB constructs in predicting how people perform actions for their own benefit rather than performing behaviors that are beneficial to others, such as breastfeeding infants. A meta-analysis approach could help clarify the breastfeeding practice to promote breastfeeding. This study used meta-analytic procedures. We searched for studies to include in our analysis, examining those published between January 1, 1990 and December 31, 2013 in PubMed, Medline, CINAHL, ProQuest, and Mosby's Index. We also reviewed journals with a history of publishing breastfeeding studies and searched reference lists for potential articles to include. Ten studies comprising a total of 2694 participants were selected for analysis. These studies yielded 10 effect sizes from the TPB, which ranged from 0.20 to 0.59. Structural equation model analysis using the pooled correlation matrix enabled us to determine the relative coefficients among TPB constructs. Attitude, subjective norms, and perceived behavioral control were all significant predictors of breastfeeding intention, whereas intention was a strong predictor of breastfeeding behavior. Perceived behavioral control reached a borderline level of significance to breastfeeding behavior. Theoretical and empirical implications are discussed from the perspective of evidence-based practice. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. A meta-analysis of response-time tests of the sequential two-systems model of moral judgment.

    Science.gov (United States)

    Baron, Jonathan; Gürçay, Burcu

    2017-05-01

    The (generalized) sequential two-system ("default interventionist") model of utilitarian moral judgment predicts that utilitarian responses often arise from a system-two correction of system-one deontological intuitions. Response-time (RT) results that seem to support this model are usually explained by the fact that low-probability responses have longer RTs. Following earlier results, we predicted response probability from each subject's tendency to make utilitarian responses (A, "Ability") and each dilemma's tendency to elicit deontological responses (D, "Difficulty"), estimated from a Rasch model. At the point where A = D, the two responses are equally likely, so probability effects cannot account for any RT differences between them. The sequential two-system model still predicts that many of the utilitarian responses made at this point will result from system-two corrections of system-one intuitions, hence should take longer. However, when A = D, RT for the two responses was the same, contradicting the sequential model. Here we report a meta-analysis of 26 data sets, which replicated the earlier results of no RT difference overall at the point where A = D. The data sets used three different kinds of moral judgment items, and the RT equality at the point where A = D held for all three. In addition, we found that RT increased with A-D. This result holds for subjects (characterized by Ability) but not for items (characterized by Difficulty). We explain the main features of this unanticipated effect, and of the main results, with a drift-diffusion model.

  10. Can cognitive models explain brain activation during word and pseudoword reading? A meta-analysis of 36 neuroimaging studies.

    Science.gov (United States)

    Taylor, J S H; Rastle, Kathleen; Davis, Matthew H

    2013-07-01

    Reading in many alphabetic writing systems depends on both item-specific knowledge used to read irregular words (sew, yacht) and generative spelling-sound knowledge used to read pseudowords (tew, yash). Research into the neural basis of these abilities has been directed largely by cognitive accounts proposed by the dual-route cascaded and triangle models of reading. We develop a framework that enables predictions for neural activity to be derived from cognitive models of reading using 2 principles: (a) the extent to which a model component or brain region is engaged by a stimulus and (b) how much effort is exerted in processing that stimulus. To evaluate the derived predictions, we conducted a meta-analysis of 36 neuroimaging studies of reading using the quantitative activation likelihood estimation technique. Reliable clusters of activity are localized during word versus pseudoword and irregular versus regular word reading and demonstrate a great deal of convergence between the functional organization of the reading system put forward by cognitive models and the neural systems activated during reading tasks. Specifically, left-hemisphere activation clusters are revealed reflecting orthographic analysis (occipitotemporal cortex), lexical and/or semantic processing (anterior fusiform, middle temporal gyrus), spelling-sound conversion (inferior parietal cortex), and phonological output resolution (inferior frontal gyrus). Our framework and results establish that cognitive models of reading are relevant for interpreting neuroimaging studies and that neuroscientific studies can provide data relevant for advancing cognitive models. This article thus provides a firm empirical foundation from which to improve integration between cognitive and neural accounts of the reading process. 2013 APA, all rights reserved

  11. A model-based meta-analysis of monoclonal antibody pharmacokinetics to guide optimal first-in-human study design

    Science.gov (United States)

    Davda, Jasmine P; Dodds, Michael G; Gibbs, Megan A; Wisdom, Wendy; Gibbs, John P

    2014-01-01

    The objectives of this retrospective analysis were (1) to characterize the population pharmacokinetics (popPK) of four different monoclonal antibodies (mAbs) in a combined analysis of individual data collected during first-in-human (FIH) studies and (2) to provide a scientific rationale for prospective design of FIH studies with mAbs. The data set was composed of 171 subjects contributing a total of 2716 mAb serum concentrations, following intravenous (IV) and subcutaneous (SC) doses. mAb PK was described by an open 2-compartment model with first-order elimination from the central compartment and a depot compartment with first-order absorption. Parameter values obtained from the popPK model were further used to generate optimal sampling times for a single dose study. A robust fit to the combined data from four mAbs was obtained using the 2-compartment model. Population parameter estimates for systemic clearance and central volume of distribution were 0.20 L/day and 3.6 L with intersubject variability of 31% and 34%, respectively. The random residual error was 14%. Differences (> 2-fold) in PK parameters were not apparent across mAbs. Rich designs (22 samples/subject), minimal designs for popPK (5 samples/subject), and optimal designs for non-compartmental analysis (NCA) and popPK (10 samples/subject) were examined by stochastic simulation and estimation. Single-dose PK studies for linear mAbs executed using the optimal designs are expected to yield high-quality model estimates, and accurate capture of NCA estimations. This model-based meta-analysis has determined typical popPK values for four mAbs with linear elimination and enabled prospective optimization of FIH study designs, potentially improving the efficiency of FIH studies for this class of therapeutics. PMID:24837591

  12. Unique effects and moderators of effects of sources on self-efficacy: A model-based meta-analysis.

    Science.gov (United States)

    Byars-Winston, Angela; Diestelmann, Jacob; Savoy, Julia N; Hoyt, William T

    2017-11-01

    Self-efficacy beliefs are strong predictors of academic pursuits, performance, and persistence, and in theory are developed and maintained by 4 classes of experiences Bandura (1986) referred to as sources: performance accomplishments (PA), vicarious learning (VL), social persuasion (SP), and affective arousal (AA). The effects of sources on self-efficacy vary by performance domain and individual difference factors. In this meta-analysis (k = 61 studies of academic self-efficacy; N = 8,965), we employed B. J. Becker's (2009) model-based approach to examine cumulative effects of the sources as a set and unique effects of each source, controlling for the others. Following Becker's recommendations, we used available data to create a correlation matrix for the 4 sources and self-efficacy, then used these meta-analytically derived correlations to test our path model. We further examined moderation of these associations by subject area (STEM vs. non-STEM), grade, sex, and ethnicity. PA showed by far the strongest unique association with self-efficacy beliefs. Subject area was a significant moderator, with sources collectively predicting self-efficacy more strongly in non-STEM (k = 14) compared with STEM (k = 47) subjects (R2 = .37 and .22, respectively). Within studies of STEM subjects, grade level was a significant moderator of the coefficients in our path model, as were 2 continuous study characteristics (percent non-White and percent female). Practical implications of the findings and future research directions are discussed. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  13. Meta-analysis of choice set generation effects on route choice model estimates and predictions

    DEFF Research Database (Denmark)

    Prato, Carlo Giacomo

    2012-01-01

    are applied for model estimation and results are compared to the ‘true model estimates’. Last, predictions from the simulation of models estimated with objective choice sets are compared to the ‘postulated predicted routes’. A meta-analytical approach allows synthesizing the effect of judgments......Large scale applications of behaviorally realistic transport models pose several challenges to transport modelers on both the demand and the supply sides. On the supply side, path-based solutions to the user assignment equilibrium problem help modelers in enhancing the route choice behavior...... modeling, but require them to generate choice sets by selecting a path generation technique and its parameters according to personal judgments. This paper proposes a methodology and an experimental setting to provide general indications about objective judgments for an effective route choice set generation...

  14. Composite modified Luneburg model of human eye lens.

    Science.gov (United States)

    Gómez-Correa, J E; Balderas-Mata, S E; Pierscionek, B K; Chávez-Cerda, S

    2015-09-01

    A new lens model based on the gradient-index Luneburg lens and composed of two oblate half spheroids of different curvatures is presented. The spherically symmetric Luneburg lens is modified to create continuous isoindicial contours and to incorporate curvatures that are similar to those found in a human lens. The imaging capabilities of the model and the changes in the gradient index profile are tested for five object distances, for a fixed geometry and for a fixed image distance. The central refractive index decreases with decreasing object distance. This indicates that in order to focus at the same image distance as is required in the eye, a decrease in refractive power is needed for rays from closer objects that meet the lens surface at steeper angles compared to rays from more distant objects. This ensures a highly focused image with no spherical aberration.

  15. Oxygen transport through soft contact lens and cornea: Lens characterization and metabolic modeling

    Science.gov (United States)

    Chhabra, Mahendra

    The human cornea requires oxygen to sustain metabolic processes critical for its normal functioning. Any restriction to corneal oxygen supply from the external environment (e.g., by wearing a low oxygen-permeability contact lens) can lead to hypoxia, which may cause corneal edema (swelling), limbal hyperemia, neovascularization, and corneal acidosis. The need for adequate oxygen to the cornea is a major driving force for research and development of hypertransmissible soft contact lenses (SCLs). Currently, there is no standard technique for measuring oxygen permeability (Dk) of hypertransmissible silicone-hydrogel SCLs. In this work, an electrochemistry-based polarographic apparatus was designed, built, and operated to measure oxygen permeability in hypertransmissible SCLs. Unlike conventional methods where a range of lens thickness is needed for determining oxygen permeabilities of SCLs, this apparatus requires only a single lens thickness. The single-lens permeameter provides a reliable, efficient, and economic tool for measuring oxygen permeabilities of commercial hypertransmissible SCLs. The single-lens permeameter measures not only the product Dk, but, following modification, it measures separately diffusivity, D, and solubility, k, of oxygen in hypertransmissible SCLs. These properties are critical for designing better lens materials that ensure sufficient oxygen supply to the cornea. Metabolism of oxygen in the cornea is influenced by contact-lens-induced hypoxia, diseases such as diabetes, surgery, and drug treatment, Thus, estimation of the in-vivo corneal oxygen consumption rate is essential for gauging adequate oxygen supply to the cornea. Therefore, we have developed an unsteady-state reactive-diffusion model for the cornea-contact-lens system to determine in-vivo human corneal oxygen-consumption rate. Finally, a metabolic model was developed to determine the relation between contact-lens oxygen transmissibility (Dk/L) and corneal oxygen deficiency. A

  16. Meta-Analysis of MicroRNAs Dysregulated in the Hippocampal Dentate Gyrus of Animal Models of Epilepsy

    NARCIS (Netherlands)

    Srivastava, Prashant K.; Roncon, Paolo; Lukasiuk, Katarzyna; Gorter, Jan A.; Aronica, Eleonora; Pitkänen, Asla; Petretto, Enrico; Johnson, Michael R.; Simonato, Michele

    2017-01-01

    The identification of mechanisms transforming normal to seizure-generating tissue after brain injury is key to developing new antiepileptogenic treatments. MicroRNAs (miRNAs) may act as regulators and potential treatment targets for epileptogenesis. Here, we undertook a meta-analysis of changes in

  17. Structural equation models for meta-analysis in environmental risk assessment

    DEFF Research Database (Denmark)

    Budtz-Jørgensen, Esben; Debes, Frodi; Weihe, Pal

    2010-01-01

    cohort was the largest by far, but a smaller cohort included superior assessment of the PCB exposure which has been considered an important confounder when estimating the mercury effect. The data were analyzed by specification of a structural equation model for each cohort. Information was then pooled...... based on a joint likelihood function with key parameters constrained to be equal in the different models. Modeling assumptions were chosen to obtain a meaningful biological interpretation of the joint effect parameters. Measurement errors in mercury variables were taken into account by viewing observed...... different outcomes to gain power and to avoid multiple testing problems. In this model, the mercury effect remained statistically significant, while the effect of PCB was less certain....

  18. Fitting identity in the reasoned action framework: A meta-analysis and model comparison.

    Science.gov (United States)

    Paquin, Ryan S; Keating, David M

    2017-01-01

    Several competing models have been put forth regarding the role of identity in the reasoned action framework. The standard model proposes that identity is a background variable. Under a typical augmented model, identity is treated as an additional direct predictor of intention and behavior. Alternatively, it has been proposed that identity measures are inadvertent indicators of an underlying intention factor (e.g., a manifest-intention model). In order to test these competing hypotheses, we used data from 73 independent studies (total N = 23,917) to conduct a series of meta-analytic structural equation models. We also tested for moderation effects based on whether there was a match between identity constructs and the target behaviors examined (e.g., if the study examined a "smoker identity" and "smoking behavior," there would be a match; if the study examined a "health conscious identity" and "smoking behavior," there would not be a match). Average effects among primary reasoned action variables were all substantial, rs = .37-.69. Results gave evidence for the manifest-intention model over the other explanations, and a moderation effect by identity-behavior matching.

  19. The Effects of Mathematical Modelling on Students’ Achievement-Meta-Analysis of Research

    Directory of Open Access Journals (Sweden)

    Andrzej Sokolowski

    2015-01-01

    Full Text Available Using meta-analytic techniques this study examined the effects of applying mathematical modelling to support student math knowledge acquisition at the high school and college levels. The research encompassed experimental studies published in peer-reviewed journals between January 1, 2000, and February 27, 2013. Such formulated orientation called for extracting individual effect sizes of student achievement from the accumulated research conducting a moderator analysis. A systematic review of literature resulted in locating13 primary research articles involving 1,670 participants. The overall mean effect size; ES = 0.69 (SE = 0.05, 95% CI: 0.59–0.79 of a medium magnitude and positive direction supported the claim that mathematical modelling helps students understand and apply math concepts. A subsequent moderator analysis revealed differences of the effect sizes due to different modelling designs, aim of the modelling process, grade levels, and content domains. The research findings along with the discussion can be of interest to mathematics curriculum designers and practitioners who use modelling in their teaching practice.

  20. Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia

    Science.gov (United States)

    Lanchares, Elena; Navarro, Rafael; Calvo, Begoña

    2012-01-01

    Purpose The modification of the mechanical properties of the human crystalline lens with age can be a major cause of presbyopia. Since these properties cannot be measured in vivo, numerical simulation can be used to estimate them. We propose an inverse method to determine age-dependent change in the material properties of the tissues composing the human crystalline lens. Methods A finite element model of a 30-year-old lens in the accommodated state was developed. The force necessary to achieve full accommodation in a 30-year-old lens of known external geometry was computed using this model. Two additional numerical models of the lens corresponding to the ages of 40 and 50 years were then built. Assuming that the accommodative force applied to the lens remains constant with age, the material properties of nucleus and cortex were estimated by inverse analysis. Results The zonular force necessary to reshape the model of a 30-year-old lens from the accommodated to the unaccommodated geometry was 0.078 newton (N). Both nucleus and cortex became stiffer with age. The stiffness of the nucleus increased with age at a higher rate than the cortex. Conclusions In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases.

  1. Integrative invasion science: model systems, multi-site studies, focused meta-analysis, and invasion syndromes

    Czech Academy of Sciences Publication Activity Database

    Kueffer, C.; Pyšek, Petr; Richardson, D. M.

    2013-01-01

    Roč. 200, č. 3 (2013), s. 615-633 ISSN 1469-8137 R&D Projects: GA ČR(CZ) GAP504/11/1028; GA ČR GA206/09/0563 Institutional support: RVO:67985939 Keywords : model systems * invasion syndromes * multi-site studies Subject RIV: EF - Botanics Impact factor: 6.545, year: 2013

  2. The Five-Factor Model of Personality Traits and Organizational Citizenship Behaviors: A Meta-Analysis

    Science.gov (United States)

    Chiaburu, Dan S.; Oh, In-Sue; Berry, Christopher M.; Li, Ning; Gardner, Richard G.

    2011-01-01

    Using meta-analytic tests based on 87 statistically independent samples, we investigated the relationships between the five-factor model (FFM) of personality traits and organizational citizenship behaviors in both the aggregate and specific forms, including individual-directed, organization-directed, and change-oriented citizenship. We found that…

  3. Bivariate Random Effects Meta-analysis of Diagnostic Studies Using Generalized Linear Mixed Models

    Science.gov (United States)

    GUO, HONGFEI; ZHOU, YIJIE

    2011-01-01

    Bivariate random effect models are currently one of the main methods recommended to synthesize diagnostic test accuracy studies. However, only the logit-transformation on sensitivity and specificity has been previously considered in the literature. In this paper, we consider a bivariate generalized linear mixed model to jointly model the sensitivities and specificities, and discuss the estimation of the summary receiver operating characteristic curve (ROC) and the area under the ROC curve (AUC). As the special cases of this model, we discuss the commonly used logit, probit and complementary log-log transformations. To evaluate the impact of misspecification of the link functions on the estimation, we present two case studies and a set of simulation studies. Our study suggests that point estimation of the median sensitivity and specificity, and AUC is relatively robust to the misspecification of the link functions. However, the misspecification of link functions has a noticeable impact on the standard error estimation and the 95% confidence interval coverage, which emphasizes the importance of choosing an appropriate link function to make statistical inference. PMID:19959794

  4. A meta-analysis and statistical modelling of nitrates in groundwater at the African scale

    Science.gov (United States)

    Ouedraogo, Issoufou; Vanclooster, Marnik

    2016-06-01

    Contamination of groundwater with nitrate poses a major health risk to millions of people around Africa. Assessing the space-time distribution of this contamination, as well as understanding the factors that explain this contamination, is important for managing sustainable drinking water at the regional scale. This study aims to assess the variables that contribute to nitrate pollution in groundwater at the African scale by statistical modelling. We compiled a literature database of nitrate concentration in groundwater (around 250 studies) and combined it with digital maps of physical attributes such as soil, geology, climate, hydrogeology, and anthropogenic data for statistical model development. The maximum, medium, and minimum observed nitrate concentrations were analysed. In total, 13 explanatory variables were screened to explain observed nitrate pollution in groundwater. For the mean nitrate concentration, four variables are retained in the statistical explanatory model: (1) depth to groundwater (shallow groundwater, typically important step towards developing tools that will allow us to accurately predict nitrate distribution at the African scale and thus may support groundwater monitoring and water management that aims to protect groundwater systems. Yet they should be further refined and validated when more detailed and harmonized data become available and/or combined with more conceptual descriptions of the fate of nutrients in the hydrosystem.

  5. THE BOSS EMISSION-LINE LENS SURVEY. IV. SMOOTH LENS MODELS FOR THE BELLS GALLERY SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Shu, Yiping [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Bolton, Adam S.; Montero-Dorta, Antonio D.; Cornachione, Matthew A.; Zheng, Zheng; Brownstein, Joel R. [Department of Physics and Astronomy, University of Utah, 115 South 1400 East, Salt Lake City, UT 84112 (United States); Mao, Shude [Physics Department and Tsinghua Centre for Astrophysics, Tsinghua University, Beijing 100084 (China); Kochanek, Christopher S. [Department of Astronomy and Center for Cosmology and Astroparticle Physics, Ohio State University, Columbus, OH 43210 (United States); Pérez-Fournon, Ismael; Marques-Chaves, Rui [Instituto de Astrofísica de Canarias, C/Vía Láctea, s/n, E-38205 San Cristóbal de La Laguna, Tenerife (Spain); Oguri, Masamune [Research Center for the Early Universe, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Ménard, Brice, E-mail: yiping.shu@nao.cas.cn [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2016-12-20

    We present Hubble Space Telescope F606W-band imaging observations of 21 galaxy-Ly α emitter lens candidates in the Baryon Oscillation Spectroscopic Survey Emission-Line Lens Survey (BELLS) for the GALaxy-Ly α EmitteR sYstems (BELLS GALLERY) survey. Seventeen systems are confirmed to be definite lenses with unambiguous evidence of multiple imaging. The lenses are primarily massive early-type galaxies (ETGs) at redshifts of approximately 0.55, while the lensed sources are Ly α emitters (LAEs) at redshifts from two to three. Although most of the lens systems are well fit by smooth lens models consisting of singular isothermal ellipsoids in an external shear field, a thorough exploration of dark substructures in the lens galaxies is required. The Einstein radii of the BELLS GALLERY lenses are, on average, 60% larger than those of the BELLS lenses because of the much higher source redshifts. This will allow for a detailed investigation of the radius evolution of the mass profile in ETGs. With the aid of the average ∼13× lensing magnification, the LAEs are frequently resolved into individual star-forming knots with a wide range of properties. They have characteristic sizes from less than 100 pc to several kiloparsecs, rest-frame far-UV apparent AB magnitudes from 29.6 to 24.2, and typical projected separations of 500 pc to 2 kpc.

  6. Theories of reasoned action and planned behavior as models of condom use: a meta-analysis.

    Science.gov (United States)

    Albarracín, D; Johnson, B T; Fishbein, M; Muellerleile, P A

    2001-01-01

    To examine how well the theories of reasoned action and planned behavior predict condom use, the authors synthesized 96 data sets (N = 22,594) containing associations between the models' key variables. Consistent with the theory of reasoned action's predictions, (a) condom use was related to intentions (weighted mean r. = .45), (b) intentions were based on attitudes (r. = .58) and subjective norms (r. = .39), and (c) attitudes were associated with behavioral beliefs (r. = .56) and norms were associated with normative beliefs (r. = .46). Consistent with the theory of planned behavior's predictions, perceived behavioral control was related to condom use intentions (r. = .45) and condom use (r. = .25), but in contrast to the theory, it did not contribute significantly to condom use. The strength of these associations, however, was influenced by the consideration of past behavior. Implications of these results for HIV prevention efforts are discussed.

  7. Identifying Generalizable Image Segmentation Parameters for Urban Land Cover Mapping through Meta-Analysis and Regression Tree Modeling

    Directory of Open Access Journals (Sweden)

    Brian A. Johnson

    2018-01-01

    Full Text Available The advent of very high resolution (VHR satellite imagery and the development of Geographic Object-Based Image Analysis (GEOBIA have led to many new opportunities for fine-scale land cover mapping, especially in urban areas. Image segmentation is an important step in the GEOBIA framework, so great time/effort is often spent to ensure that computer-generated image segments closely match real-world objects of interest. In the remote sensing community, segmentation is frequently performed using the multiresolution segmentation (MRS algorithm, which is tuned through three user-defined parameters (the scale, shape/color, and compactness/smoothness parameters. The scale parameter (SP is the most important parameter and governs the average size of generated image segments. Existing automatic methods to determine suitable SPs for segmentation are scene-specific and often computationally intensive, so an approach to estimating appropriate SPs that is generalizable (i.e., not scene-specific could speed up the GEOBIA workflow considerably. In this study, we attempted to identify generalizable SPs for five common urban land cover types (buildings, vegetation, roads, bare soil, and water through meta-analysis and nonlinear regression tree (RT modeling. First, we performed a literature search of recent studies that employed GEOBIA for urban land cover mapping and extracted the MRS parameters used, the image properties (i.e., spatial and radiometric resolutions, and the land cover classes mapped. Using this data extracted from the literature, we constructed RT models for each land cover class to predict suitable SP values based on the: image spatial resolution, image radiometric resolution, shape/color parameter, and compactness/smoothness parameter. Based on a visual and quantitative analysis of results, we found that for all land cover classes except water, relatively accurate SPs could be identified using our RT modeling results. The main advantage of our

  8. Assessing quality of health services with the SERVQUAL model in Iran. A systematic review and meta-analysis.

    Science.gov (United States)

    Teshnizi, Saeed Hosseini; Aghamolaei, Teamur; Kahnouji, Kobra; Teshnizi, Seyyed Mehrdad Hosseini; Ghani, Jalil

    2018-03-01

    The five-dimension service quality (SERVQUAL) scale is one of the most common tools for evaluating gaps between clients' perceptions and expectations. This study aimed to assess the quality of health services in Iran through a meta-analysis of all Iranian studies which used the SERVQUAL tool. A systematic literature review has been performed in Web of Science, PubMed, Scopus, Google Scholar, Iran Medex, Magiran and Scientific Information Database. All relevant English or Persian studies published between January 2009 and April 2016 were have been selected. Papers were considered if they regarded all five dimensions of the SERVQUAL tool for assessing the quality of health care services. Two reviewer independently extracted mean and standard deviation of five dimensions and characteristics of studies. The quality of studies included in meta-analysis using STROBE checklist. Of 315 studies initially identified, 12 were included in our meta-analysis. All analyses were performed in Stata MP v. 14. Patients' perceptions were lower than their expectations (gap = -1.64). Responsibility (-1.22) and reliability (-1.15) had the lowest gaps, and tangibility and empathy (-1.03) had the largest gaps. Except gender, other variables had no significant associations with gaps. Patients in the cities of Arak (-3.47) and Shiraz (-3.02) had the largest gaps. All dimensions of service quality were negative, which implies that the quality of health services in Iran has not been satisfying to patients and needs to be improved.

  9. Multilevel mixed effects parametric survival models using adaptive Gauss-Hermite quadrature with application to recurrent events and individual participant data meta-analysis.

    Science.gov (United States)

    Crowther, Michael J; Look, Maxime P; Riley, Richard D

    2014-09-28

    Multilevel mixed effects survival models are used in the analysis of clustered survival data, such as repeated events, multicenter clinical trials, and individual participant data (IPD) meta-analyses, to investigate heterogeneity in baseline risk and covariate effects. In this paper, we extend parametric frailty models including the exponential, Weibull and Gompertz proportional hazards (PH) models and the log logistic, log normal, and generalized gamma accelerated failure time models to allow any number of normally distributed random effects. Furthermore, we extend the flexible parametric survival model of Royston and Parmar, modeled on the log-cumulative hazard scale using restricted cubic splines, to include random effects while also allowing for non-PH (time-dependent effects). Maximum likelihood is used to estimate the models utilizing adaptive or nonadaptive Gauss-Hermite quadrature. The methods are evaluated through simulation studies representing clinically plausible scenarios of a multicenter trial and IPD meta-analysis, showing good performance of the estimation method. The flexible parametric mixed effects model is illustrated using a dataset of patients with kidney disease and repeated times to infection and an IPD meta-analysis of prognostic factor studies in patients with breast cancer. User-friendly Stata software is provided to implement the methods. Copyright © 2014 John Wiley & Sons, Ltd.

  10. D-galactose-induced brain ageing model: A systematic review and meta-analysis on cognitive outcomes and oxidative stress indices.

    Science.gov (United States)

    Sadigh-Eteghad, Saeed; Majdi, Alireza; McCann, Sarah K; Mahmoudi, Javad; Vafaee, Manouchehr S; Macleod, Malcolm R

    2017-01-01

    Animal models are commonly used in brain ageing research. Amongst these, models where rodents are exposed to d-galactose are held to recapitulate a number of features of ageing including neurobehavioral and neurochemical changes. However, results from animal studies are often inconsistent. To better understand the characteristics of the model and effects of d-galactose on neurobehavioral and neurochemical outcomes in rodents we performed a systematic review and meta-analysis. We applied random-effects meta-analysis to evaluate the effect of study features. Our results give an overview of the characteristics of the d-galactose rodent ageing model, including neurobehavioral and neurochemical outcomes. We found that few studies took measures to reduce risks of bias, and substantial heterogeneity in the reported effects of d-galactose in included studies. This highlights the need for improvements in the use of the d-galactose rodent ageing model if it is to provide useful in the development of drugs to treat human ageing.

  11. Meta-analysis for the comparison of two diagnostic tests to a common gold standard: A generalized linear mixed model approach.

    Science.gov (United States)

    Hoyer, Annika; Kuss, Oliver

    2016-08-02

    Meta-analysis of diagnostic studies is still a rapidly developing area of biostatistical research. Especially, there is an increasing interest in methods to compare different diagnostic tests to a common gold standard. Restricting to the case of two diagnostic tests, in these meta-analyses the parameters of interest are the differences of sensitivities and specificities (with their corresponding confidence intervals) between the two diagnostic tests while accounting for the various associations across single studies and between the two tests. We propose statistical models with a quadrivariate response (where sensitivity of test 1, specificity of test 1, sensitivity of test 2, and specificity of test 2 are the four responses) as a sensible approach to this task. Using a quadrivariate generalized linear mixed model naturally generalizes the common standard bivariate model of meta-analysis for a single diagnostic test. If information on several thresholds of the tests is available, the quadrivariate model can be further generalized to yield a comparison of full receiver operating characteristic (ROC) curves. We illustrate our model by an example where two screening methods for the diagnosis of type 2 diabetes are compared. © The Author(s) 2016.

  12. A Review of Meta-Analysis Packages in R

    Science.gov (United States)

    Polanin, Joshua R.; Hennessy, Emily A.; Tanner-Smith, Emily E.

    2017-01-01

    Meta-analysis is a statistical technique that allows an analyst to synthesize effect sizes from multiple primary studies. To estimate meta-analysis models, the open-source statistical environment R is quickly becoming a popular choice. The meta-analytic community has contributed to this growth by developing numerous packages specific to…

  13. Quantifying the dose-response relationship between circulating folate concentrations and colorectal cancer in cohort studies: a meta-analysis based on a flexible meta-regression model.

    Science.gov (United States)

    Chuang, Shu-Chun; Rota, Matteo; Gunter, Marc J; Zeleniuch-Jacquotte, Anne; Eussen, Simone J P M; Vollset, Stein Emil; Ueland, Per Magne; Norat, Teresa; Ziegler, Regina G; Vineis, Paolo

    2013-10-01

    Most epidemiologic studies on folate intake suggest that folate may be protective against colorectal cancer, but the results on circulating (plasma or serum) folate are mostly inconclusive. We conducted a meta-analysis of case-control studies nested within prospective studies on circulating folate and colorectal cancer risk by using flexible meta-regression models to test the linear and nonlinear dose-response relationships. A total of 8 publications (10 cohorts, representing 3,477 cases and 7,039 controls) were included in the meta-analysis. The linear and nonlinear models corresponded to relative risks of 0.96 (95% confidence interval (CI): 0.91, 1.02) and 0.99 (95% CI: 0.96, 1.02), respectively, per 10 nmol/L of circulating folate in contrast to the reference value. The pooled relative risks when comparing the highest with the lowest category were 0.80 (95% CI: 0.61, 0.99) for radioimmunoassay and 1.03 (95% CI: 0.83, 1.22) for microbiological assay. Overall, our analyses suggest a null association between circulating folate and colorectal cancer risk. The stronger association for the radioimmunoassay-based studies could reflect differences in cohorts and study designs rather than assay performance. Further investigations need to integrate more accurate measurements and flexible modeling to explore the effects of folate in the presence of genetic, lifestyle, dietary, and hormone-related factors.

  14. Mesenchymal stem cells provide prophylaxis against acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation: A meta-analysis of animal models.

    Science.gov (United States)

    Wang, Li; Zhang, Haiyan; Guan, Lixun; Zhao, Shasha; Gu, Zhenyang; Wei, Huaping; Gao, Zhe; Wang, Feiyan; Yang, Nan; Luo, Lan; Li, Yonghui; Wang, Lili; Liu, Daihong; Gao, Chunji

    2016-09-20

    A meta-analysis of animal models was conducted to evaluate the prophylactic effects of mesenchymal stem cells (MSCs) on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation. A total of 50 studies involving 1848 animals were included. The pooled results showed that MSCs significantly reduced aGVHD-associated mortality (risk ratio = 0.70, 95% confidence interval 0.62 to 0.79, P = 2.73×10-9) and clinical scores (standardized mean difference = -3.60, 95% confidence interval -4.43 to -2.76, P = 3.61×10-17). In addition, MSCs conferred robust favorable prophylactic effects on aGVHD across recipient species, MSC doses, and administration times, but not MSC sources. Our meta-analysis showed that MSCs significantly prevented mortality and alleviated the clinical manifestations of aGVHD in animal models. These data support further clinical trials aimed at evaluating the efficacy of using MSCs to prevent aGVHD.

  15. GRAVITATIONAL LENS MODELING WITH GENETIC ALGORITHMS AND PARTICLE SWARM OPTIMIZERS

    International Nuclear Information System (INIS)

    Rogers, Adam; Fiege, Jason D.

    2011-01-01

    Strong gravitational lensing of an extended object is described by a mapping from source to image coordinates that is nonlinear and cannot generally be inverted analytically. Determining the structure of the source intensity distribution also requires a description of the blurring effect due to a point-spread function. This initial study uses an iterative gravitational lens modeling scheme based on the semilinear method to determine the linear parameters (source intensity profile) of a strongly lensed system. Our 'matrix-free' approach avoids construction of the lens and blurring operators while retaining the least-squares formulation of the problem. The parameters of an analytical lens model are found through nonlinear optimization by an advanced genetic algorithm (GA) and particle swarm optimizer (PSO). These global optimization routines are designed to explore the parameter space thoroughly, mapping model degeneracies in detail. We develop a novel method that determines the L-curve for each solution automatically, which represents the trade-off between the image χ 2 and regularization effects, and allows an estimate of the optimally regularized solution for each lens parameter set. In the final step of the optimization procedure, the lens model with the lowest χ 2 is used while the global optimizer solves for the source intensity distribution directly. This allows us to accurately determine the number of degrees of freedom in the problem to facilitate comparison between lens models and enforce positivity on the source profile. In practice, we find that the GA conducts a more thorough search of the parameter space than the PSO.

  16. Effect of psychiatric consultation models in primary care. A systematic review and meta-analysis of randomized clinical trials.

    Science.gov (United States)

    van der Feltz-Cornelis, Christina M; Van Os, Titus W D P; Van Marwijk, Harm W J; Leentjens, Albert F G

    2010-06-01

    Psychiatric consultation in primary care is meant to enhance and improve treatment for mental disorder in that setting. An estimate of the effect for different conditions as well as identification of particularly effective elements is needed. Database search for randomized controlled trials (RCTs) on psychiatric consultation in primary care. Validity assessment and data extraction according to Cochrane criteria were performed by independent assessors in duplicate. Meta-analysis was performed. Data were collected from 10 RCTs with a total of 3408 included patients with somatoform disorder or depressive disorder, which compared psychiatric consultation to care as usual (CAU). Meta-analysis irrespective of condition showed a weighted mean indicating a combined assessment of illness burden as outcome of psychiatric consultation, compared to CAU, of 0.313 (95% CI 0.190-0.437). The effect was especially large in somatoform disorder (0.614; 95% CI 0.206-1.022). RCTs in which after the consult, consultation advice was given by means of a consultation letter, showed a combined weighted mean effect size of 0.561 (95% CI 0.337-0.786), while studies not using such a letter showed a small effect of 0.210 (95% CI 0.102-0.319). Effects are highest on utilization of health care services with 0.507 (95% CI 0.305-0.708). Psychiatric consultation in the primary care setting is effective in patients with somatoform and depressive disorder. Largest effects are seen in reduction of utilization of health care services. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Systematic review and meta-analysis of efficacy of mesenchymal stem cells on locomotor recovery in animal models of traumatic brain injury.

    Science.gov (United States)

    Peng, Weijun; Sun, Jing; Sheng, Chenxia; Wang, Zhe; Wang, Yang; Zhang, Chunhu; Fan, Rong

    2015-03-26

    The therapeutic potential of mesenchymal stem cells (MSCs) for traumatic brain injury (TBI) is attractive. Conducting systematic review and meta-analyses based on data from animal studies can be used to inform clinical trial design. To conduct a systematic review and meta-analysis to (i) systematically review the literatures describing the effect of MSCs therapy in animal models of TBI, (ii) determine the estimated effect size of functional locomotor recovery after experimental TBI, and (iii) to provide empirical evidence of biological factors associated with greater efficacy. We conducted a systematic search of PubMed, EMBASE, and Web of Science and hand searched related references. Studies were selected if they reported the efficacy of MSCs in animal models of TBI. Two investigators independently assessed the identified studies. We extracted the details of individual study characteristics from each publication, assessed study quality, evaluated the effect sizes of MSCs treatment, and performed stratified meta-analysis and meta-regression, to assess the influence of study design on the estimated effect size. The presence of small effect sizes was investigated using funnel plots and Egger's tests. Twenty-eight eligible controlled studies were identified. The study quality was modest. Between-study heterogeneity was large. Meta-analysis showed that MSCs exert statistically significant positive effects on sensorimotor and neurological motor function. For sensorimotor function, maximum effect size in studies with a quality score of 5 was found in the weight-drop impact injury TBI model established in male SD rats, to which syngeneic umbilical cord-derived MSCs intracerebrally at cell dose of (1-5)×10(6) was administered r 6 hours following TBI, using ketamine as anesthetic agent. For neurological motor function, effect size was maximum for studies with a quality score of 5, in which the weight-drop impact injury TBI models of the female Wistar rats were adopted, with

  18. Modeling the effects of temperature and pH on the resistance of Alicyclobacillus acidoterrestris in conventional heat-treated fruit beverages through a meta-analysis approach.

    Science.gov (United States)

    Silva, Leonardo P; Gonzales-Barron, Ursula; Cadavez, Vasco; Sant'Ana, Anderson S

    2015-04-01

    In this work, all publicly-accessible published findings on Alicyclobacillus acidoterrestris heat resistance in fruit beverages as affected by temperature and pH were compiled. Then, study characteristics (protocols, fruit and variety, °Brix, pH, temperature, heating medium, culture medium, inactivation method, strains, etc.) were extracted from the primary studies, and some of them incorporated to a meta-analysis mixed-effects linear model based on the basic Bigelow equation describing the heat resistance parameters of this bacterium. The model estimated mean D* values (time needed for one log reduction at a temperature of 95 °C and a pH of 3.5) of Alicyclobacillus in beverages of different fruits, two different concentration types, with and without bacteriocins, and with and without clarification. The zT (temperature change needed to cause one log reduction in D-values) estimated by the meta-analysis model were compared to those ('observed' zT values) reported in the primary studies, and in all cases they were within the confidence intervals of the model. The model was capable of predicting the heat resistance parameters of Alicyclobacillus in fruit beverages beyond the types available in the meta-analytical data. It is expected that the compilation of the thermal resistance of Alicyclobacillus in fruit beverages, carried out in this study, will be of utility to food quality managers in the determination or validation of the lethality of their current heat treatment processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. The Effectiveness of the Problem-Based Learning Teaching Model for Use in Introductory Chinese Undergraduate Medical Courses: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Zhang, Yanqi; Zhou, Liang; Liu, Xiaoyu; Liu, Ling; Wu, Yazhou; Zhao, Zengwei; Yi, Dali; Yi, Dong

    2015-01-01

    Background Although the problem-based learning (PBL) emerged in 1969 and was soon widely applied internationally, the rapid development in China only occurred in the last 10 years. This study aims to compare the effect of PBL and lecture-based learning (LBL) on student course examination results for introductory Chinese undergraduate medical courses. Methods Randomized and nonrandomized controlled trial studies on PBL use in Chinese undergraduate medical education were retrieved through PubMed, the Excerpta Medica Database (EMBASE), Chinese National Knowledge Infrastructure (CNKI) and VIP China Science and Technology Journal Database (VIP-CSTJ) with publication dates from 1st January 1966 till 31 August 2014. The pass rate, excellence rate and examination scores of course examination were collected. Methodological quality was evaluated based on the modified Jadad scale. The I-square statistic and Chi-square test of heterogeneity were used to assess the statistical heterogeneity. Overall RRs or SMDs with their 95% CIs were calculated in meta-analysis. Meta-regression and subgroup meta-analyses were also performed based on comparators and other confounding factors. Funnel plots and Egger’s tests were performed to assess degrees of publication bias. Results The meta-analysis included 31studies and 4,699 subjects. Fourteen studies were of high quality with modified Jadad scores of 4 to 6, and 17 studies were of low quality with scores of 1 to 3. Relative to the LBL model, the PBL model yielded higher course examination pass rates [RR = 1.09, 95%CI (1.03, 1.17)], excellence rates [RR = 1.66, 95%CI (1.33, 2.06)] and examination scores [SMD = 0.82, 95%CI (0.63, 1.01)]. The meta-regression results show that course type was the significant confounding factor that caused heterogeneity in the examination-score meta-analysis (t = 0.410, Pteaching model application in introductory undergraduate medical courses can increase course examination excellence rates and scores in

  20. The effectiveness of the problem-based learning teaching model for use in introductory Chinese undergraduate medical courses: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Yanqi Zhang

    Full Text Available Although the problem-based learning (PBL emerged in 1969 and was soon widely applied internationally, the rapid development in China only occurred in the last 10 years. This study aims to compare the effect of PBL and lecture-based learning (LBL on student course examination results for introductory Chinese undergraduate medical courses.Randomized and nonrandomized controlled trial studies on PBL use in Chinese undergraduate medical education were retrieved through PubMed, the Excerpta Medica Database (EMBASE, Chinese National Knowledge Infrastructure (CNKI and VIP China Science and Technology Journal Database (VIP-CSTJ with publication dates from 1st January 1966 till 31 August 2014. The pass rate, excellence rate and examination scores of course examination were collected. Methodological quality was evaluated based on the modified Jadad scale. The I-square statistic and Chi-square test of heterogeneity were used to assess the statistical heterogeneity. Overall RRs or SMDs with their 95% CIs were calculated in meta-analysis. Meta-regression and subgroup meta-analyses were also performed based on comparators and other confounding factors. Funnel plots and Egger's tests were performed to assess degrees of publication bias.The meta-analysis included 31studies and 4,699 subjects. Fourteen studies were of high quality with modified Jadad scores of 4 to 6, and 17 studies were of low quality with scores of 1 to 3. Relative to the LBL model, the PBL model yielded higher course examination pass rates [RR = 1.09, 95%CI (1.03, 1.17], excellence rates [RR = 1.66, 95%CI (1.33, 2.06] and examination scores [SMD = 0.82, 95%CI (0.63, 1.01]. The meta-regression results show that course type was the significant confounding factor that caused heterogeneity in the examination-score meta-analysis (t = 0.410, P<0.001. The examination score SMD in "laboratory course" subgroup [SMD = 2.01, 95% CI: (1.50, 2.52] was higher than that in "theory course" subgroup [SMD = 0

  1. Meta-analysis approach as a gene selection method in class prediction: does it improve model performance? : A case study in acute myeloid leukemia

    NARCIS (Netherlands)

    P.W. Novianti (Putri W.); V.L. Jong (Victor L.); K.C. Roes (Kit); M.J.C. Eijkemans (René)

    2017-01-01

    markdownabstractBackground: Aggregating gene expression data across experiments via meta-analysis is expected to increase the precision of the effect estimates and to increase the statistical power to detect a certain fold change. This study evaluates the potential benefit of using a meta-analysis

  2. Meta-analysis approach as a gene selection method in class prediction : does it improve model performance? A case study in acute myeloid leukemia

    NARCIS (Netherlands)

    Novianti, Putri W; Jong, Victor L; Roes, Kit C B|info:eu-repo/dai/nl/115147020; Eijkemans, Marinus J C|info:eu-repo/dai/nl/156353253

    2017-01-01

    BACKGROUND: Aggregating gene expression data across experiments via meta-analysis is expected to increase the precision of the effect estimates and to increase the statistical power to detect a certain fold change. This study evaluates the potential benefit of using a meta-analysis approach as a

  3. Meta-analysis approach as a gene selection method in class prediction: Does it improve model performance? A case study in acute myeloid leukemia

    NARCIS (Netherlands)

    P.W. Novianti (Putri W.); V.L. Jong (Victor L.); K.C. Roes (Kit); M.J.C. Eijkemans (René)

    2017-01-01

    textabstractBackground: Aggregating gene expression data across experiments via meta-analysis is expected to increase the precision of the effect estimates and to increase the statistical power to detect a certain fold change. This study evaluates the potential benefit of using a meta-analysis

  4. Modeling Corneal Oxygen with Scleral Gas Permeable Lens Wear.

    Science.gov (United States)

    Compañ, Vicente; Aguilella-Arzo, Marcel; Edrington, Timothy B; Weissman, Barry A

    2016-11-01

    The main goal of this current work is to use an updated calculation paradigm, and updated boundary conditions, to provide theoretical guidelines to assist the clinician whose goal is to improve his or her scleral gas permeable (GP) contact lens wearing patients' anterior corneal oxygen supply. Our model uses a variable value of corneal oxygen consumption developed through Monod equations that disallows negative oxygen tensions within the stroma to predict oxygen tension at the anterior corneal surface of scleral GP contact lens wearing eyes, and to describe oxygen tension and flux profiles, for various boundary conditions, through the lens, tears, and cornea. We use several updated tissue and boundary parameters in our model. Tear exchange with GP scleral lenses is considered nonexistent in this model. The majority of current scleral GP contact lenses should produce some levels of corneal hypoxia under open eye conditions. Only lenses producing the thinnest of tear vaults should result in anterior corneal surface oxygen tensions greater than a presumed critical oxygen tension of 100 mmHg. We also find that corneal oxygen tension and flux are each more sensitive to modification in tear vault than to changes in lens oxygen permeability, within the ranges of current clinical manipulation. Our study suggests that clinicians would be prudent to prescribe scleral GP lenses manufactured from higher oxygen permeability materials and especially to fit without excessive corneal clearance.

  5. Three-Dimensional Modeling of Glass Lens Molding

    DEFF Research Database (Denmark)

    Sarhadi, Ali; Hattel, Jesper Henri; Hansen, Hans Nørgaard

    2015-01-01

    The required accuracy for the final dimensions of the molded lenses in wafer-based precision glass molding as well as the need for elimination of costly experimental trial and error calls for numerical simulations. This study deals with 3D thermo-mechanical modeling of the wafer-based precision...... glass lens molding process. First, a comprehensive 3D thermo-mechanical model of glass is implemented into a FORTRAN user subroutine (UMAT) in the FE program ABAQUS, and the developed FE model is validated with both a well-known sandwich seal test and experimental results of precision molding of several...... glass rings. Afterward, 3D thermo-mechanical modeling of the wafer-based glass lens manufacturing is performed to suggest a proper molding program (i.e., the proper set of process parameters including preset force-time and temperature-time histories) for molding a wafer to a desired dimension...

  6. The efficacy of Schwann cell transplantation on motor function recovery after spinal cord injuries in animal models: A systematic review and meta-analysis.

    Science.gov (United States)

    Hosseini, Mostafa; Yousefifard, Mahmoud; Baikpour, Masoud; Rahimi-Movaghar, Vafa; Nasirinezhad, Farinaz; Younesian, Somaye; Safari, Saeed; Ghelichkhani, Parisa; Moghadas Jafari, Ali

    2016-12-01

    This article aimed to assess the efficacy of Schwann cell transplantation on motor function recovery in animal model of spinal cord injuries via meta-analysis. An extended search was carried out in the electronic databases of Medline (via PubMed), EMBASE (via OvidSP), CENTRAL, SCOPUS, Web of Science (BIOSIS), and ProQuest. Finally, 41 eligible studies conducted on 1046 animals including 517 control animals and 529 transplanted animals were included in the meta-analysis. Pooled standardized mean difference (SMD) and odds ratio (OR) with 95% confidence interval (95% CI) were reported. The findings showed that treatment with Schwann cells leads to a modest motor function recovery after spinal cord injury (SMD=0.85; 95% CI: 0.63-1.07; pcells in acute phase of the injury (immediately after the injury) (OR=4.30; 95% CI: 1.53-12.05; p=0.007), application of mesenchymal/skin-derived precursors (OR=2.34; 95% CI: 1.28-4.29; p=0.008), and cells with human sources are associated with an increase in efficacy of Schwann cells (OR=10.96; 95% CI: 1.49-80.77; p=0.02). Finally, it seems that the efficacy of Schwann cells in mice is significantly lower than rats (OR=0.03; 95% CI: 0.003-0.41; p=0.009). Transplantation of Schwann cells can moderately improve motor function recovery. It seems that inter-species differences might exist regarding the efficacy of this cells. Therefore, this should be taken into account when using Schwann cells in clinical trials regarding spinal cord injuries. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Use of a problem-based learning teaching model for undergraduate medical and nursing education: a systematic review and meta-analysis.

    Science.gov (United States)

    Sayyah, Mehdi; Shirbandi, Kiarash; Saki-Malehi, Amal; Rahim, Fakher

    2017-01-01

    The aim of this systematic review and meta-analysis was to evaluate the problem-based learning (PBL) method as an alternative to conventional educational methods in Iranian undergraduate medical courses. We systematically searched international datasets banks, including PubMed, Scopus, and Embase, and internal resources of banks, including MagirIran, IranMedex, IranDoc, and Scientific Information Database (SID), using appropriate search terms, such as "PBL", "problem-based learning", "based on problems", "active learning", and" learner centered", to identify PBL studies, and these were combined with other key terms such as "medical", "undergraduate", "Iranian", "Islamic Republic of Iran", "I.R. of Iran", and "Iran". The search included the period from 1980 to 2016 with no language limits. Overall, a total of 1,057 relevant studies were initially found, of which 21 studies were included in the systematic review and meta-analysis. Of the 21 studies, 12 (57.14%) had a high methodological quality. Considering the pooled effect size data, there was a significant difference in the scores (standardized mean difference [SMD]=0.80, 95% CI [0.52, 1.08], P based method. Subgroup analysis revealed that using PBL alone is more favorable compared to using a mixed model with other learning methods such as lecture-based learning (LBL). The results of this systematic review showed that using PBL may have a positive effect on the academic achievement of undergraduate medical courses. The results suggest that teachers and medical education decision makers give more attention on using this method for effective and proper training.

  8. Meta-analysis for psychiatric research using free software R.

    Science.gov (United States)

    Chen, Ding-Geng

    2015-06-25

    This paper provides a brief overview of meta-analysis (MA) with emphasis on classical fixedeffects and random-effects MA models. It illustrates the application of MA models with the open-source software R using publicly available data from five studies on lamotrigine to treat bipolar depression and finds that meta-analysis identifies a statistically significant advantage of lamotrigine over placebo that was not evident in the individual studies.

  9. A thermal lens model including the Soret effect

    International Nuclear Information System (INIS)

    Cabrera, Humberto; Sira, Eloy; Rahn, Kareem; Garcia-Sucre, Maximo

    2009-01-01

    In this letter we generalize the thermal lens model to account for the Soret effect in binary liquid mixtures. This formalism permits the precise determination of the Soret coefficient in a steady-state situation. The theory is experimentally verified using the measured values in the ethanol/water mixtures. The time evolution of the Soret signal has been used to derive mass-diffusion times from which mass-diffusion coefficients were calculated. (Author)

  10. Network meta-analysis of longitudinal data using fractional polynomials.

    Science.gov (United States)

    Jansen, J P; Vieira, M C; Cope, S

    2015-07-10

    Network meta-analysis of randomized controlled trials (RCTs) are often based on one treatment effect measure per study. However, many studies report data at multiple time points. Furthermore, not all studies measure the outcomes at the same time points. As an alternative to a network meta-analysis based on a synthesis of the results at one time point, a network meta-analysis method is presented that allows for the simultaneous analysis of outcomes at multiple time points. The development of outcomes over time of interventions compared in an RCT is modeled with fractional polynomials, and the differences between the parameters of these polynomials within a trial are synthesized across studies with a Bayesian network meta-analysis. The proposed models are illustrated with an analysis of RCTs evaluating interventions for osteoarthritis of the knee. Fixed and random effects second order fractional polynomials were applied to the case study. Network meta-analysis with models that represent the treatment effects in terms of several parameters using fractional polynomials can be considered a useful addition to models for network meta-analysis of repeated measures previously proposed. When RCTs report treatment effects at multiple follow-up times, these models can be used to synthesize the results even if reporting times differ across the studies. Copyright © 2015 John Wiley & Sons, Ltd.

  11. Gravitational lens models of arcs in clusters

    International Nuclear Information System (INIS)

    Bergmann, A.G.; Petrosian, V.; Lynds, R.

    1990-01-01

    It is now well established that the luminous arcs discovered in clusters of galaxies, in particular those in Abell 370 and Cluster 2244-02, are produced by gravitational lensing of background sources. The arcs are modeled and constraints are placed on the distribution of the mass in the clusters and the shape and size of the sources. The models require, as expected, a large amount of dark matter in the clusters and a mass-to blue-light ratio for the cluster which exceeds 100 solar mass/solar luminosity and could be as high as 1000 solar mass/solar luminosity depending on cosmological parameters and the distribution of the dark matter. Furthermore, it is found that in the case of the arc in A370 the dark matter must have a different distribution than the luminous galaxies, while for the arc in Cl 2244 the dark matter can have a distribution similar to that of the light matter (galaxies) or a separate distribution. 30 refs

  12. Multivariate meta-analysis: Potential and promise

    Science.gov (United States)

    Jackson, Dan; Riley, Richard; White, Ian R

    2011-01-01

    The multivariate random effects model is a generalization of the standard univariate model. Multivariate meta-analysis is becoming more commonly used and the techniques and related computer software, although continually under development, are now in place. In order to raise awareness of the multivariate methods, and discuss their advantages and disadvantages, we organized a one day ‘Multivariate meta-analysis’ event at the Royal Statistical Society. In addition to disseminating the most recent developments, we also received an abundance of comments, concerns, insights, critiques and encouragement. This article provides a balanced account of the day's discourse. By giving others the opportunity to respond to our assessment, we hope to ensure that the various view points and opinions are aired before multivariate meta-analysis simply becomes another widely used de facto method without any proper consideration of it by the medical statistics community. We describe the areas of application that multivariate meta-analysis has found, the methods available, the difficulties typically encountered and the arguments for and against the multivariate methods, using four representative but contrasting examples. We conclude that the multivariate methods can be useful, and in particular can provide estimates with better statistical properties, but also that these benefits come at the price of making more assumptions which do not result in better inference in every case. Although there is evidence that multivariate meta-analysis has considerable potential, it must be even more carefully applied than its univariate counterpart in practice. Copyright © 2011 John Wiley & Sons, Ltd. PMID:21268052

  13. Diagnostic performance of alpha-fetoprotein, lens culinaris agglutinin-reactive alpha-fetoprotein, des-gamma carboxyprothrombin, and glypican-3 for the detection of hepatocellular carcinoma: a systematic review and meta-analysis protocol.

    Science.gov (United States)

    Huang, Ting-Shuo; Shyu, Yu-Chiau; Turner, Robin; Chen, Huang-Yang; Chen, Pei-Jer

    2013-06-06

    Diagnosis of early-stage hepatocellular carcinoma (HCC) followed by curative resection or liver transplantation offers the best chance for long-term patient survival. Clinically, ultrasonography has suboptimal sensitivity for detecting early-stage HCC. Several serological tests including alpha-fetoprotein (AFP), the ratio of lens culinaris agglutinin-reactive alpha-fetoprotein to total AFP (AFP-L3/AFP), des-gamma carboxyprothrombin (DCP), and glypican-3 (GPC-3) have been widely investigated as diagnostic biomarkers for early-stage HCC in at-risk populations. However, these tests are not recommended for routine HCC screening. Our objective is to determine the diagnostic performance of AFP, AFP-L3/AFP, DCP, and GPC-3 for the detection of HCC, particularly early-stage tumors meeting the Milan criteria. We will include cross-sectional studies that consecutively or randomly recruit target populations. We will search the Cochrane Library, Medline, Embase, Science Citation Index, and the Chinese National Knowledge Infrastructure. We will also search the MEDION and ARIF databases to identify diagnostic systematic reviews that include primary studies. Reference lists of relevant reviews will be searched for additional trials. Language restrictions will not be applied. Two reviewers will independently screen study eligibility and extract data. Methodological quality will be assessed according to the revised tool for the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Two authors will apply the QUADAS-2 assessment to all the included studies, and any discrepancies will be resolved by the third author. The following test characteristics will be extracted into 2 × 2 tables for all included studies: true positives, false positives, true negatives, and false negatives. Study-specific estimates of sensitivity and specificity with 95% confidence intervals will be displayed in forest plots. When possible, we will use the bivariate random-effects model or the Rutter

  14. Meta-analysis: Its role in psychological methodology

    Directory of Open Access Journals (Sweden)

    Andrej Kastrin

    2008-11-01

    Full Text Available Meta-analysis refers to the statistical analysis of a large collection of independent observations for the purpose of integrating results. The main objectives of this article are to define meta-analysis as a method of data integration, to draw attention to some particularities of its use, and to encourage researchers to use meta-analysis in their work. The benefits of meta-analysis include more effective exploitation of existing data from independent sources and contribution to more powerful domain knowledge. It may also serve as a support tool to generate new research hypothesis. The idea of combining results of independent studies addressing the same research question dates back to sixteenth century. Metaanalysis was reinvented in 1976 by Glass, to refute the conclusion of an eminent colleague, Eysenck, that psychotherapy was essentially ineffective. We review some major historical landmarks of metaanalysis and its statistical background. We present the concept of effect size measure, the problem of heterogeneity and two models which are used to combine individual effect sizes (fixed and random effect model in great details. Two visualization techniques, forest and funnel plot graphics are demonstrated. We developed RMetaWeb, simple and fast web server application to conduct meta-analysis online. RMetaWeb is the first web meta-analysis application and is completely based on R software environment for statistical computing and graphics.

  15. Meta-Analysis in Marketing

    Directory of Open Access Journals (Sweden)

    Vinicius Andrade Brei

    2014-05-01

    Full Text Available Meta-analysis is a method that seeks to aggregate, integrate, and adjust results from previous studies, while considering the different conditions in which the original studies were investigated. The expected benefit is demonstration of the association between one or more variables, and generation of a systematic review and integration of studies. Hence, in the meta-analysis, the researcher can present broad evidence for or against a given theory. This study discusses the methodological and structural aspects of the organization of meta-analytical investigations in marketing. In addition, this paper suggests eight steps to organize the data and interpret the results. Lastly, we discuss the implications of the formulas and the corrections of the effects, as well as proposing paths for investigations that use meta-analysis in marketing. 

  16. Mixed modeling of meta-analysis P-values (MixMAP suggests multiple novel gene loci for low density lipoprotein cholesterol.

    Directory of Open Access Journals (Sweden)

    Andrea S Foulkes

    Full Text Available Informing missing heritability for complex disease will likely require leveraging information across multiple SNPs within a gene region simultaneously to characterize gene and locus-level contributions to disease phenotypes. To this aim, we introduce a novel strategy, termed Mixed modeling of Meta-Analysis P-values (MixMAP, that draws on a principled statistical modeling framework and the vast array of summary data now available from genetic association studies, to test formally for locus level association. The primary inputs to this approach are: (a single SNP level p-values for tests of association; and (b the mapping of SNPs to genomic regions. The output of MixMAP is comprised of locus level estimates and tests of association. In application of MixMAP to summary data from the Global Lipids Gene Consortium, we suggest twelve new loci (PKN, FN1, UGT1A1, PPARG, DMDGH, PPARD, CDK6, VPS13B, GAD2, GAB2, APOH and NPC1 for low-density lipoprotein cholesterol (LDL-C, a causal risk factor for cardiovascular disease and we also demonstrate the potential utility of MixMAP in small data settings. Overall, MixMAP offers novel and complementary information as compared to SNP-based analysis approaches and is straightforward to implement with existing open-source statistical software tools.

  17. Assisted delivery of antisense therapeutics in animal models of heritable neurodegenerative and neuromuscular disorders: a systematic review and meta-analysis.

    Science.gov (United States)

    van der Bent, M Leontien; Paulino da Silva Filho, Omar; van Luijk, Judith; Brock, Roland; Wansink, Derick G

    2018-03-08

    Antisense oligonucleotide (AON)-based therapies hold promise for a range of neurodegenerative and neuromuscular diseases and have shown benefit in animal models and patients. Success in the clinic is nevertheless still limited, due to unfavourable biodistribution and poor cellular uptake of AONs. Extensive research is currently being conducted into the formulation of AONs to improve delivery, but thus far there is no consensus on which of those strategies will be the most effective. This systematic review was designed to answer in an unbiased manner which delivery strategies most strongly enhance the efficacy of AONs in animal models of heritable neurodegenerative and neuromuscular diseases. In total, 95 primary studies met the predefined inclusion criteria. Study characteristics and data on biodistribution and toxicity were extracted and reporting quality and risk of bias were assessed. Twenty studies were eligible for meta-analysis. We found that even though the use of delivery systems provides an advantage over naked AONs, it is not yet possible to select the most promising strategies. Importantly, standardisation of experimental procedures is warranted in order to reach conclusions about the most efficient delivery strategies. Our best practice guidelines for future experiments serve as a step in that direction.

  18. Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

    Science.gov (United States)

    Warriner, David R; Brown, Alistair G; Varma, Susheel; Sheridan, Paul J; Lawford, Patricia; Hose, David R; Al-Mohammad, Abdallah; Shi, Yubing

    2014-01-01

    The American Heart Association (AHA)/American College of Cardiology (ACC) guidelines for the classification of heart failure (HF) are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV) pressure-volume (PV) loop data and secondly use the LV PV loop data to create stage specific HF models. A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV), ejection fraction (EF%) decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax). For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.

  19. Closing the loop: modelling of heart failure progression from health to end-stage using a meta-analysis of left ventricular pressure-volume loops.

    Directory of Open Access Journals (Sweden)

    David R Warriner

    Full Text Available INTRODUCTION: The American Heart Association (AHA/American College of Cardiology (ACC guidelines for the classification of heart failure (HF are descriptive but lack precise and objective measures which would assist in categorising such patients. Our aim was two fold, firstly to demonstrate quantitatively the progression of HF through each stage using a meta-analysis of existing left ventricular (LV pressure-volume (PV loop data and secondly use the LV PV loop data to create stage specific HF models. METHODS AND RESULTS: A literature search yielded 31 papers with PV data, representing over 200 patients in different stages of HF. The raw pressure and volume data were extracted from the papers using a digitising software package and the means were calculated. The data demonstrated that, as HF progressed, stroke volume (SV, ejection fraction (EF% decreased while LV volumes increased. A 2-element lumped parameter model was employed to model the mean loops and the error was calculated between the loops, demonstrating close fit between the loops. The only parameter that was consistently and statistically different across all the stages was the elastance (Emax. CONCLUSIONS: For the first time, the authors have created a visual and quantitative representation of the AHA/ACC stages of LVSD-HF, from normal to end-stage. The study demonstrates that robust, load-independent and reproducible parameters, such as elastance, can be used to categorise and model HF, complementing the existing classification. The modelled PV loops establish previously unknown physiological parameters for each AHA/ACC stage of LVSD-HF, such as LV elastance and highlight that it this parameter alone, in lumped parameter models, that determines the severity of HF. Such information will enable cardiovascular modellers with an interest in HF, to create more accurate models of the heart as it fails.

  20. CRITICAL CURVES AND CAUSTICS OF TRIPLE-LENS MODELS

    International Nuclear Information System (INIS)

    Daněk, Kamil; Heyrovský, David

    2015-01-01

    Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses. We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang–Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius

  1. Effectiveness and cost-effectiveness of antidepressants in primary care: a multiple treatment comparison meta-analysis and cost-effectiveness model.

    Directory of Open Access Journals (Sweden)

    Joakim Ramsberg

    Full Text Available OBJECTIVE: To determine effectiveness and cost-effectiveness over a one-year time horizon of pharmacological first line treatment in primary care for patients with moderate to severe depression. DESIGN: A multiple treatment comparison meta-analysis was employed to determine the relative efficacy in terms of remission of 10 antidepressants (citalopram, duloxetine escitalopram, fluoxetine, fluvoxamine mirtazapine, paroxetine, reboxetine, sertraline and venlafaxine. The estimated remission rates were then applied in a decision-analytic model in order to estimate costs and quality of life with different treatments at one year. DATA SOURCES: Meta-analyses of remission rates from randomised controlled trials, and cost and quality-of-life data from published sources. RESULTS: The most favourable pharmacological treatment in terms of remission was escitalopram with an 8- to 12-week probability of remission of 0.47. Despite a high acquisition cost, this clinical effectiveness translated into escitalopram being both more effective and having a lower total cost than all other comparators from a societal perspective. From a healthcare perspective, the cost per QALY of escitalopram was €3732 compared with venlafaxine. CONCLUSION: Of the investigated antidepressants, escitalopram has the highest probability of remission and is the most effective and cost-effective pharmacological treatment in a primary care setting, when evaluated over a one year time-horizon. Small differences in remission rates may be important when assessing costs and cost-effectiveness of antidepressants.

  2. So different, yet so similar: meta-analysis and policy modeling of willingness to participate in clinical trials among Brazilians and Indians.

    Directory of Open Access Journals (Sweden)

    Guilherme Zammar

    Full Text Available BACKGROUND: With the global expansion of clinical trials and the expectations of the rise of the emerging economies known as BRICs (Brazil, Russia, India and China, the understanding of factors that affect the willingness to participate in clinical trials of patients from those countries assumes a central role in the future of health research. METHODS: We conducted a systematic review and meta-analysis (SRMA of willingness to participate in clinical trials among Brazilian patients and then we compared it with Indian patients (with results of another SRMA previously conducted by our group through a system dynamics model. RESULTS: Five studies were included in the SRMA of Brazilian patients. Our main findings are 1 the major motivation for Brazilian patients to participate in clinical trials is altruism, 2 monetary reimbursement is the least important factor motivating Brazilian patients, 3 the major barrier for Brazilian patients to not participate in clinical trials is the fear of side effects, and 4 Brazilian patients are more likely willing to participate in clinical trials than Indians. CONCLUSION: Our study provides important insights for investigators and sponsors for planning trials in Brazil (and India in the future. Ignoring these results may lead to unnecessary fund/time spending. More studies are needed to validate our results and for better understanding of this poorly studied theme.

  3. Effectiveness and Cost-Effectiveness of Antidepressants in Primary Care: A Multiple Treatment Comparison Meta-Analysis and Cost-Effectiveness Model

    Science.gov (United States)

    Ramsberg, Joakim; Asseburg, Christian; Henriksson, Martin

    2012-01-01

    Objective To determine effectiveness and cost-effectiveness over a one-year time horizon of pharmacological first line treatment in primary care for patients with moderate to severe depression. Design A multiple treatment comparison meta-analysis was employed to determine the relative efficacy in terms of remission of 10 antidepressants (citalopram, duloxetine escitalopram, fluoxetine, fluvoxamine mirtazapine, paroxetine, reboxetine, sertraline and venlafaxine). The estimated remission rates were then applied in a decision-analytic model in order to estimate costs and quality of life with different treatments at one year. Data Sources Meta-analyses of remission rates from randomised controlled trials, and cost and quality-of-life data from published sources. Results The most favourable pharmacological treatment in terms of remission was escitalopram with an 8- to 12-week probability of remission of 0.47. Despite a high acquisition cost, this clinical effectiveness translated into escitalopram being both more effective and having a lower total cost than all other comparators from a societal perspective. From a healthcare perspective, the cost per QALY of escitalopram was €3732 compared with venlafaxine. Conclusion Of the investigated antidepressants, escitalopram has the highest probability of remission and is the most effective and cost-effective pharmacological treatment in a primary care setting, when evaluated over a one year time-horizon. Small differences in remission rates may be important when assessing costs and cost-effectiveness of antidepressants. PMID:22876296

  4. So different, yet so similar: meta-analysis and policy modeling of willingness to participate in clinical trials among Brazilians and Indians.

    Science.gov (United States)

    Zammar, Guilherme; Meister, Henrique; Shah, Jatin; Phadtare, Amruta; Cofiel, Luciana; Pietrobon, Ricardo

    2010-12-16

    With the global expansion of clinical trials and the expectations of the rise of the emerging economies known as BRICs (Brazil, Russia, India and China), the understanding of factors that affect the willingness to participate in clinical trials of patients from those countries assumes a central role in the future of health research. We conducted a systematic review and meta-analysis (SRMA) of willingness to participate in clinical trials among Brazilian patients and then we compared it with Indian patients (with results of another SRMA previously conducted by our group) through a system dynamics model. Five studies were included in the SRMA of Brazilian patients. Our main findings are 1) the major motivation for Brazilian patients to participate in clinical trials is altruism, 2) monetary reimbursement is the least important factor motivating Brazilian patients, 3) the major barrier for Brazilian patients to not participate in clinical trials is the fear of side effects, and 4) Brazilian patients are more likely willing to participate in clinical trials than Indians. Our study provides important insights for investigators and sponsors for planning trials in Brazil (and India) in the future. Ignoring these results may lead to unnecessary fund/time spending. More studies are needed to validate our results and for better understanding of this poorly studied theme.

  5. Meta-analysis and time series modeling allow a systematic review of primary HIV-1 drug-resistant prevalence in Latin America and Caribbean.

    Science.gov (United States)

    Coelho, Antonio Victor Campos; De Moura, Ronald Rodrigues; Da Silva, Ronaldo Celerino; Kamada, Anselmo Jiro; Guimarães, Rafael Lima; Brandão, Lucas André Cavalcanti; Coelho, Hemílio Fernandes Campos; Crovella, Sergio

    2015-01-01

    Here we review the prevalence of HIV-1 primary drug resistance in Latin America and Caribbean using meta-analysis as well as time-series modeling. We also discuss whether there could be a drawback to HIV/AIDS programs due to drug resistance in Latin America and Caribbean in the next years. We observed that, although some studies report low or moderate primary drug resistance prevalence in Caribbean countries, this evidence needs to be updated. In other countries, such as Brazil and Argentina, the prevalence of drug resistance appears to be rising. Mutations conferring resistance against reverse transcriptase inhibitors were the most frequent in the analyzed populations (70% of all mutational events). HIV-1 subtype B was the most prevalent in Latin America and the Caribbean, although subtype C and B/F recombinants have significant contributions in Argentina and Brazil. Thus, we suggest that primary drug resistance in Latin America and the Caribbean could have been underestimated. Clinical monitoring should be improved to offer better therapy, reducing the risk for HIV-1 resistance emergence and spread, principally in vulnerable populations, such as men who have sex with men transmission group, sex workers and intravenous drug users.

  6. Meta-analysis in epidemiology

    African Journals Online (AJOL)

    1990-07-21

    Jul 21, 1990 ... sciences.8. •. 9 The term refers to the 'epidemiology of results'. Stated more formally, Jenicek3 has defined meta-analysis as. 'the structured and systematic qualitative and quantitative integration of the ... In reality, most research involves re-search! ... Centre for Epidemiological Research in Southern Mrica,.

  7. Online open neuroimaging mass meta-analysis

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup; Kempton, Matthew J.; Williams, Steven C. R.

    We describe a system for meta-analysis where a wiki stores numerical data in a simple format and a web service performs the numerical computation. We initially apply the system on multiple meta-analyses of structural neuroimaging data results. The described system allows for mass meta-analysis, e.......g., meta-analysis across multiple brain regions and multiple mental disorders....

  8. Causal Meta-Analysis : Methodology and Applications

    NARCIS (Netherlands)

    Bax, L.J.

    2009-01-01

    Meta-analysis is a statistical method to summarize research data from multiple studies in a quantitative manner. This dissertation addresses a number of methodological topics in causal meta-analysis and reports the development and validation of meta-analysis software. In the first (methodological)

  9. The murine lens: A model to investigate in vivo epithelial-mesenchymal transition.

    Science.gov (United States)

    Shirai, Kumi; Tanaka, Sai-Ichi; Lovicu, Frank J; Saika, Shizuya

    2018-03-01

    Epithelial-mesenchymal transition (EMT) produces myofibroblasts that contribute to the formation of fibrotic tissue with an impairment of tissue homeostasis and functionality. The crystalline lens of the eye is a unique transparent and isolated tissue. The lens vesicle becomes isolated from the surface ectoderm, its cells are all contained as they line the inner surface of the lens capsule. Clinically the formation of fibrotic tissue by the lens epithelial cells causes a type of cataract or opacification and contraction of the lens capsule postcataract surgery. Production of EMT in the intact animal lens by using specific gene transfer to the lens or experimental lens injury has been shown to be a powerful tool to investigate EMT processes. It is not easy to uncover whether the origin of the myofibroblast is epithelial cell-derived or from other cell lineages in fibrotic tissues. However, myofibroblasts that appear in the crystalline lens pathology are totally derived from the lens epithelial cells for the reasons mentioned above. Here, we report on different animal models of lens EMT, using either transgenic approaches or injury to study the biological aspects of EMT. Developmental Dynamics 247:340-345, 2018. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. © 2017 The Authors Developmental Dynamics published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

  10. Meta-Analysis of the Structural Equation Models' Parameters for the Estimation of Brain Connectivity with fMRI

    Directory of Open Access Journals (Sweden)

    Joan Guàrdia-Olmos

    2018-02-01

    Full Text Available Structural Equation Models (SEM is among of the most extensively applied statistical techniques in the study of human behavior in the fields of Neuroscience and Cognitive Neuroscience. This paper reviews the application of SEM to estimate functional and effective connectivity models in work published since 2001. The articles analyzed were compiled from Journal Citation Reports, PsycInfo, Pubmed, and Scopus, after searching with the following keywords: fMRI, SEMs, and Connectivity.Results: A 100 papers were found, of which 25 were rejected due to a lack of sufficient data on basic aspects of the construction of SEM. The other 75 were included and contained a total of 160 models to analyze, since most papers included more than one model. The analysis of the explained variance (R2 of each model yields an effect of the type of design used, the type of population studied, the type of study, the existence of recursive effects in the model, and the number of paths defined in the model. Along with these comments, a series of recommendations are included for the use of SEM to estimate of functional and effective connectivity models.

  11. A systematic review and meta-analysis of the effort-reward imbalance model of workplace stress with indicators of immune function.

    Science.gov (United States)

    Eddy, Pennie; Heckenberg, Rachael; Wertheim, Eleanor H; Kent, Stephen; Wright, Bradley J

    2016-12-01

    Despite considerable research into associations between the effort reward imbalance (ERI) model and various health outcomes over the past 20years, the underlying mechanisms responsible for the association remain unclear. Recently, ERI investigations have examined associations with immune sub-systems (e.g., leukocytes, cytokines and immunoglobulins). Synthesis of the amalgamated research evidence will aid clarity to this field of enquiry. We conducted a meta-analysis and reviewed the associations of ERI and over-commitment (OC) in the workplace with immunity. Electronic databases were searched with the phrase 'effort reward imbalance' which initially yielded 319 studies leading to 57 full text studies being screened. Seven studies that met inclusion criteria were combined using mixed and random effects models. Greater ERI was associated with lower immunity (r=-0.09, CI -0.14, -0.05, p<0.001). Sub-group analyses revealed the effect with mucosal immunity was stronger (r=-0.33, CI -0.47 to -0.18) than trends between both cytokine (r=-0.04, CI -0.07, -0.01) and leukocyte sub-groups (r=-0.02 CI -0.04, 0.01) respectively (k=7, N=9952). Over-commitment was also associated with lower immunity (r=-0.05, CI -0.09, 0.01, p=0.014); subgroup (leukocytes, cytokines, mucosal immunity) associations, however, were homogenous (Q=1.83, df=2, p=0.400, k=6, N=2358). Greater ERI and OC were both associated with lower immunity. The association between mucosal immunity and ERI was stronger than the cytokine and leukocyte sub-groups. OC moderated the relationship between ERI and immunity. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Network meta-analysis of survival data with fractional polynomials

    Directory of Open Access Journals (Sweden)

    Jansen Jeroen P

    2011-05-01

    Full Text Available Abstract Background Pairwise meta-analysis, indirect treatment comparisons and network meta-analysis for aggregate level survival data are often based on the reported hazard ratio, which relies on the proportional hazards assumption. This assumption is implausible when hazard functions intersect, and can have a huge impact on decisions based on comparisons of expected survival, such as cost-effectiveness analysis. Methods As an alternative to network meta-analysis of survival data in which the treatment effect is represented by the constant hazard ratio, a multi-dimensional treatment effect approach is presented. With fractional polynomials the hazard functions of interventions compared in a randomized controlled trial are modeled, and the difference between the parameters of these fractional polynomials within a trial are synthesized (and indirectly compared across studies. Results The proposed models are illustrated with an analysis of survival data in non-small-cell lung cancer. Fixed and random effects first and second order fractional polynomials were evaluated. Conclusion (Network meta-analysis of survival data with models where the treatment effect is represented with several parameters using fractional polynomials can be more closely fitted to the available data than meta-analysis based on the constant hazard ratio.

  13. Network meta-analysis of survival data with fractional polynomials.

    Science.gov (United States)

    Jansen, Jeroen P

    2011-05-06

    Pairwise meta-analysis, indirect treatment comparisons and network meta-analysis for aggregate level survival data are often based on the reported hazard ratio, which relies on the proportional hazards assumption. This assumption is implausible when hazard functions intersect, and can have a huge impact on decisions based on comparisons of expected survival, such as cost-effectiveness analysis. As an alternative to network meta-analysis of survival data in which the treatment effect is represented by the constant hazard ratio, a multi-dimensional treatment effect approach is presented. With fractional polynomials the hazard functions of interventions compared in a randomized controlled trial are modeled, and the difference between the parameters of these fractional polynomials within a trial are synthesized (and indirectly compared) across studies. The proposed models are illustrated with an analysis of survival data in non-small-cell lung cancer. Fixed and random effects first and second order fractional polynomials were evaluated. (Network) meta-analysis of survival data with models where the treatment effect is represented with several parameters using fractional polynomials can be more closely fitted to the available data than meta-analysis based on the constant hazard ratio.

  14. Revisiting the Affect Regulation Model of Binge Eating: A Meta-Analysis of Studies Using Ecological Momentary Assessment

    Science.gov (United States)

    Haedt-Matt, Alissa A.; Keel, Pamela K.

    2011-01-01

    The affect regulation model of binge eating, which posits that patients binge eat to reduce negative affect (NA), has received support from cross-sectional and laboratory-based studies. Ecological momentary assessment (EMA) involves momentary ratings and repeated assessments over time and is ideally suited to identify temporal antecedents and…

  15. Determinants of Multiple Semantic Priming: A Meta-Analysis and Spike Frequency Adaptive Model of a Cortical Network

    Science.gov (United States)

    Lavigne, Frederic; Dumercy, Laurent; Darmon, Nelly

    2011-01-01

    Recall and language comprehension while processing sequences of words involves multiple semantic priming between several related and/or unrelated words. Accounting for multiple and interacting priming effects in terms of underlying neuronal structure and dynamics is a challenge for current models of semantic priming. Further elaboration of current…

  16. Global meta-analysis of transcriptomics studies.

    Directory of Open Access Journals (Sweden)

    José Caldas

    Full Text Available Transcriptomics meta-analysis aims at re-using existing data to derive novel biological hypotheses, and is motivated by the public availability of a large number of independent studies. Current methods are based on breaking down studies into multiple comparisons between phenotypes (e.g. disease vs. healthy, based on the studies' experimental designs, followed by computing the overlap between the resulting differential expression signatures. While useful, in this methodology each study yields multiple independent phenotype comparisons, and connections are established not between studies, but rather between subsets of the studies corresponding to phenotype comparisons. We propose a rank-based statistical meta-analysis framework that establishes global connections between transcriptomics studies without breaking down studies into sets of phenotype comparisons. By using a rank product method, our framework extracts global features from each study, corresponding to genes that are consistently among the most expressed or differentially expressed genes in that study. Those features are then statistically modelled via a term-frequency inverse-document frequency (TF-IDF model, which is then used for connecting studies. Our framework is fast and parameter-free; when applied to large collections of Homo sapiens and Streptococcus pneumoniae transcriptomics studies, it performs better than similarity-based approaches in retrieving related studies, using a Medical Subject Headings gold standard. Finally, we highlight via case studies how the framework can be used to derive novel biological hypotheses regarding related studies and the genes that drive those connections. Our proposed statistical framework shows that it is possible to perform a meta-analysis of transcriptomics studies with arbitrary experimental designs by deriving global expression features rather than decomposing studies into multiple phenotype comparisons.

  17. Kinetic modelling and meta-analysis of the B. subtilis SigA regulatory network during spore germination and outgrowth

    Czech Academy of Sciences Publication Activity Database

    Ramaniuk, Olga; Černý, Martin; Krásný, Libor; Vohradský, Jiří

    2017-01-01

    Roč. 1860, č. 8 (2017), s. 894-904 ISSN 1874-9399 R&D Projects: GA MŠk(CZ) LM2015055; GA ČR GA13-16842S; GA MZd(CZ) NV17-29680A Institutional support: RVO:61388971 Keywords : Sigma A * Kinetic modelling * Regulatory network Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 5.018, year: 2016

  18. The Efficacy of Trastuzumab in Animal Models of Breast Cancer: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Jiarong Chen

    Full Text Available Breast cancer is the most frequent cancers and is the second leading cause of cancer death among women. Trastuzumab is an effective treatment, the first monoclonal antibody directed against the human epidermal growth factor receptor 2 (HER2. To inform the development of other effective treatments we report summary estimates of efficacy of trastuzumab on survival and tumour volume in animal models of breast cancer.We searched PubMed and EMBASE systematically to identify publications testing trastuzumab in animal models of breast cancer. Data describing tumour volume, median survival and animal features were extracted and we assessed quality using a 12-item checklist. We analysed the impact of study design and quality and evidence for publication bias.We included data from 83 studies reporting 169 experiments using 2076 mice. Trastuzumab treatment caused a substantial reduction in tumour growth, with tumours in treated animals growing to 32.6% of the volume of tumours in control animals (95%CI 27.8%-38.2%. Median survival was prolonged by a factor of 1.45 (1.30-1.62. Many study design and quality features accounted for between-study heterogeneity and we found evidence suggesting publication bias.We have found trastuzumab to be effective in animal breast cancer models across a range of experimental circumstances. However the presence of publication bias and a low prevalence of measures to reduce bias provide a focus for future improvements in preclinical breast cancer research.

  19. Is the Meta-Analysis of Correlation Coefficients Accurate When Population Correlations Vary?

    Science.gov (United States)

    Field, Andy P.

    2005-01-01

    One conceptualization of meta-analysis is that studies within the meta-analysis are sampled from populations with mean effect sizes that vary (random-effects models). The consequences of not applying such models and the comparison of different methods have been hotly debated. A Monte Carlo study compared the efficacy of Hedges and Vevea's…

  20. Development of a 3D finite element model of lens microcirculation

    Directory of Open Access Journals (Sweden)

    Vaghefi Ehsan

    2012-09-01

    Full Text Available Abstract Background It has been proposed that in the absence of a blood supply, the ocular lens operates an internal microcirculation system. This system delivers nutrients, removes waste products and maintains ionic homeostasis in the lens. The microcirculation is generated by spatial differences in membrane transport properties; and previously has been modelled by an equivalent electrical circuit and solved analytically. While effective, this approach did not fully account for all the anatomical and functional complexities of the lens. To encapsulate these complexities we have created a 3D finite element computer model of the lens. Methods Initially, we created an anatomically-correct representative mesh of the lens. We then implemented the Stokes and advective Nernst-Plank equations, in order to model the water and ion fluxes respectively. Next we complemented the model with experimentally-measured surface ionic concentrations as boundary conditions and solved it. Results Our model calculated the standing ionic concentrations and electrical potential gradients in the lens. Furthermore, it generated vector maps of intra- and extracellular space ion and water fluxes that are proposed to circulate throughout the lens. These fields have only been measured on the surface of the lens and our calculations are the first 3D representation of their direction and magnitude in the lens. Conclusion Values for steady state standing fields for concentration and electrical potential plus ionic and fluid fluxes calculated by our model exhibited broad agreement with observed experimental values. Our model of lens function represents a platform to integrate new experimental data as they emerge and assist us to understand how the integrated structure and function of the lens contributes to the maintenance of its transparency.

  1. Systematic review, meta-analysis and economic modelling of molecular diagnostic tests for antibiotic resistance in tuberculosis.

    Science.gov (United States)

    Drobniewski, Francis; Cooke, Mary; Jordan, Jake; Casali, Nicola; Mugwagwa, Tendai; Broda, Agnieszka; Townsend, Catherine; Sivaramakrishnan, Anand; Green, Nathan; Jit, Mark; Lipman, Marc; Lord, Joanne; White, Peter J; Abubakar, Ibrahim

    2015-01-01

    BACKGROUND Drug-resistant tuberculosis (TB), especially multidrug-resistant (MDR, resistance to rifampicin and isoniazid) disease, is associated with a worse patient outcome. Drug resistance diagnosed using microbiological culture takes days to weeks, as TB bacteria grow slowly. Rapid molecular tests for drug resistance detection (1 day) are commercially available and may promote faster initiation of appropriate treatment. OBJECTIVES To (1) conduct a systematic review of evidence regarding diagnostic accuracy of molecular genetic tests for drug resistance, (2) conduct a health-economic evaluation of screening and diagnostic strategies, including comparison of alternative models of service provision and assessment of the value of targeting rapid testing at high-risk subgroups, and (3) construct a transmission-dynamic mathematical model that translates the estimates of diagnostic accuracy into estimates of clinical impact. REVIEW METHODS AND DATA SOURCES A standardised search strategy identified relevant studies from EMBASE, PubMed, MEDLINE, Bioscience Information Service (BIOSIS), System for Information on Grey Literature in Europe Social Policy & Practice (SIGLE) and Web of Science, published between 1 January 2000 and 15 August 2013. Additional 'grey' sources were included. Quality was assessed using quality assessment of diagnostic accuracy studies version 2 (QUADAS-2). For each diagnostic strategy and population subgroup, a care pathway was constructed to specify which medical treatments and health services that individuals would receive from presentation to the point where they either did or did not complete TB treatment successfully. A total cost was estimated from a health service perspective for each care pathway, and the health impact was estimated in terms of the mean discounted quality-adjusted life-years (QALYs) lost as a result of disease and treatment. Costs and QALYs were both discounted at 3.5% per year. An integrated transmission-dynamic and

  2. Systematic review, meta-analysis and economic modelling of molecular diagnostic tests for antibiotic resistance in tuberculosis.

    Science.gov (United States)

    Drobniewski, Francis; Cooke, Mary; Jordan, Jake; Casali, Nicola; Mugwagwa, Tendai; Broda, Agnieszka; Townsend, Catherine; Sivaramakrishnan, Anand; Green, Nathan; Jit, Mark; Lipman, Marc; Lord, Joanne; White, Peter J; Abubakar, Ibrahim

    2015-05-01

    Drug-resistant tuberculosis (TB), especially multidrug-resistant (MDR, resistance to rifampicin and isoniazid) disease, is associated with a worse patient outcome. Drug resistance diagnosed using microbiological culture takes days to weeks, as TB bacteria grow slowly. Rapid molecular tests for drug resistance detection (1 day) are commercially available and may promote faster initiation of appropriate treatment. To (1) conduct a systematic review of evidence regarding diagnostic accuracy of molecular genetic tests for drug resistance, (2) conduct a health-economic evaluation of screening and diagnostic strategies, including comparison of alternative models of service provision and assessment of the value of targeting rapid testing at high-risk subgroups, and (3) construct a transmission-dynamic mathematical model that translates the estimates of diagnostic accuracy into estimates of clinical impact. A standardised search strategy identified relevant studies from EMBASE, PubMed, MEDLINE, Bioscience Information Service (BIOSIS), System for Information on Grey Literature in Europe Social Policy & Practice (SIGLE) and Web of Science, published between 1 January 2000 and 15 August 2013. Additional 'grey' sources were included. Quality was assessed using quality assessment of diagnostic accuracy studies version 2 (QUADAS-2). For each diagnostic strategy and population subgroup, a care pathway was constructed to specify which medical treatments and health services that individuals would receive from presentation to the point where they either did or did not complete TB treatment successfully. A total cost was estimated from a health service perspective for each care pathway, and the health impact was estimated in terms of the mean discounted quality-adjusted life-years (QALYs) lost as a result of disease and treatment. Costs and QALYs were both discounted at 3.5% per year. An integrated transmission-dynamic and economic model was used to evaluate the cost-effectiveness of

  3. Revisiting the Affect Regulation Model of Binge Eating: A Meta-Analysis of Studies using Ecological Momentary Assessment

    Science.gov (United States)

    Haedt-Matt, Alissa A.; Keel, Pamela K.

    2011-01-01

    The affect regulation model of binge eating, which posits that patients binge eat to reduce negative affect (NA), has received support from cross-sectional and laboratory-based studies. Ecological momentary assessment (EMA) involves momentary ratings and repeated assessments over time and is ideally suited to identify temporal antecedents and consequences of binge eating. This meta-analytic review includes EMA studies of affect and binge eating. Electronic database and manual searches produced 36 EMA studies with N = 968 participants (89% Caucasian women). Meta-analyses examined changes in affect before and after binge eating using within-subjects standardized mean gain effect sizes (ES). Results supported greater NA preceding binge eating relative to average affect (ES = .63) and affect before regular eating (ES = .68). However, NA increased further following binge episodes (ES = .50). Preliminary findings suggested that NA decreased following purging in Bulimia Nervosa (ES = −.46). Moderators included diagnosis (with significantly greater elevations of NA prior to bingeing in Binge Eating Disorder compared to Bulimia Nervosa) and binge definition (with significantly smaller elevations of NA before binge versus regular eating episodes for the DSM definition compared to lay definitions of binge eating). Overall, results fail to support the affect regulation model of binge eating and challenge reductions in NA as a maintenance factor for binge eating. However, limitations of this literature include unidimensional analyses of NA and inadequate examination of affect during binge eating as binge eating may regulate only specific facets of affect or may reduce NA only during the episode. PMID:21574678

  4. Review of the Experimental Background and Implementation of Computational Models of the Ocular Lens Microcirculation.

    Science.gov (United States)

    Wu, Ho-Ting D; Donaldson, Paul J; Vaghefi, Ehsan

    2016-01-01

    Our sense of vision is critically dependent on the clarity of the crystalline lens. The most common cause of transparency loss in the lens is age-related nuclear cataract, which is due to accumulative oxidative damage to this tissue. Since the ocular lens is an avascular tissue, it has to maintain its physiological homeostasis and antioxidant levels using a system of water microcirculation. This system has been experimentally imaged in animal lenses using different modalities. Based on these data, computational models have been developed to predict the properties of this system in human lenses and its changes due to aging. Although successful in predicting many aspects of lens fluid dynamics, at least in animal models, these in-silica models still need further improvement to become more accurate and representative of human ocular lens. We have been working on gathering experimental data and simultaneously developing computational models of lens microcirculation for the past decade. This review chronologically looks at the development of data-driven computational foundations of lens microcirculation model, its current state, and future advancement directions. A comprehensive model of lens fluid dynamics is essential to understand the physiological optics of this tissue and ultimately the underlying mechanisms of cataract onset and progression.

  5. Hydropower externalities: A meta-analysis

    International Nuclear Information System (INIS)

    Mattmann, Matteo; Logar, Ivana; Brouwer, Roy

    2016-01-01

    This paper presents a meta-analysis of existing research related to the economic valuation of the external effects of hydropower. A database consisting of 81 observations derived from 29 studies valuing the non-market impacts of hydropower electricity generation is constructed with the main aim to quantify and explain the economic values for positive and negative hydropower externalities. Different meta-regression model specifications are used to test the robustness of significant determinants of non-market values, including different types of hydropower impacts. The explanatory and predictive power of the estimated models is relatively high. Whilst controlling for sample and study characteristics, we find significant evidence for public aversion towards deteriorations of landscape, vegetation and wildlife caused by hydropower projects. There is however only weak evidence of willingness to pay for mitigating these effects. The main positive externality of hydropower generation, the avoidance of greenhouse gas emission, positively influences welfare estimates when combined with the share of hydropower in national energy production. Sensitivity to scope is detected, but not linked to specific externalities or non-market valuation methods. - Highlights: • A global meta-analysis of valuation studies of hydropower externalities is presented. • Positive and negative externalities are distinguished. • Welfare losses due to environmental deteriorations outweigh gains of GHG reductions. • There is only weak evidence of public WTP for mitigating negative externalities. • The non-market values of hydropower externalities are sensitive to scope.

  6. Get Real in Individual Participant Data (IPD) Meta-Analysis: A Review of the Methodology

    Science.gov (United States)

    Debray, Thomas P. A.; Moons, Karel G. M.; van Valkenhoef, Gert; Efthimiou, Orestis; Hummel, Noemi; Groenwold, Rolf H. H.; Reitsma, Johannes B.

    2015-01-01

    Individual participant data (IPD) meta-analysis is an increasingly used approach for synthesizing and investigating treatment effect estimates. Over the past few years, numerous methods for conducting an IPD meta-analysis (IPD-MA) have been proposed, often making different assumptions and modeling choices while addressing a similar research…

  7. Child-Centered Play Therapy in the Schools: Review and Meta-Analysis

    Science.gov (United States)

    Ray, Dee C.; Armstrong, Stephen A.; Balkin, Richard S.; Jayne, Kimberly M.

    2015-01-01

    The authors conducted a meta-analysis and systematic review that examined 23 studies evaluating the effectiveness of child centered play therapy (CCPT) conducted in elementary schools. Meta-analysis results were explored using a random effects model for mean difference and mean gain effect size estimates. Results revealed statistically significant…

  8. Life history of the Harlequin ladybird, Harmonia axyridis; a global meta-analysis

    NARCIS (Netherlands)

    Raak-van den Berg, C.L.; Hemerik, A.; Werf, van der W.; Jong, de P.W.; Lenteren, van J.C.

    2017-01-01

    Data collected en used for a meta analysis on life history data of H. axyridis. And the resulting 20 best models for each life history characteristic. Published in the paper: Life history of the Harlequin ladybird, Harmonia axyridis; a global meta-analysis.

  9. Sex differences in behavioral outcome following neonatal hypoxia ischemia: insights from a clinical meta-analysis and a rodent model of induced hypoxic ischemic brain injury.

    Science.gov (United States)

    Smith, Amanda L; Alexander, Michelle; Rosenkrantz, Ted S; Sadek, Mona Lisa; Fitch, R Holly

    2014-04-01

    Hypoxia ischemia (HI; reduced oxygen and/or blood flow to the brain) is one of the most common injuries among preterm infants and term infants with birth complications. Both populations show cognitive/behavioral deficits, including impairments in sensory, learning/memory, and attention domains. Clinical data suggests a sex difference in HI outcomes, with males exhibiting more severe cognitive/behavioral deficits relative to matched females. Our laboratory has also reported more severe behavioral deficits among male rats with induced HI relative to females with comparable injury (Hill et al., 2011a,b). The current study initially examined published clinical studies from the past 20years where long-term IQ outcome scores for matched groups of male and female premature infants were reported separately (IQ being the most common outcome measure). A meta-analysis revealed a female "advantage," as indicated by significantly better scores on performance and full scale IQ (but not verbal IQ) for premature females. We then utilized a rodent model of neonatal HI injury to assess sham and postnatal day 7 (P7) HI male and female rats on a battery of behavioral tasks. Results showed expected deficits in HI male rats, but also showed task-dependent sex differences, with HI males having significantly larger deficits than HI females on some tasks but equivalent deficits on other tasks. In contrast to behavioral results, post mortem neuropathology associated with HI was comparable across sex. These findings suggest: 1) neonatal female "protection" in some behavioral domains, as indexed by superior outcome following early injury relative to males; and 2) female protection may entail sex-specific plasticity or compensation, rather than a reduction in gross neuropathology. Further exploration of the mechanisms underlying this sex effect could aid in neuroprotection efforts for at-risk neonates in general, and males in particular. Moreover, our current report of comparable anatomical

  10. Implications for water use of a shift from annual to perennial crops - A stochastic modelling approach based on a trait meta-analysis

    Science.gov (United States)

    Vico, Giulia; Brunsell, Nathaniel

    2017-04-01

    The projected population growth and changes in climate and dietary habits will further increase the pressure on water resources globally. Within precision farming, a host of technical solutions has been developed to reduce water consumption for agricultural uses. The next frontier for a more sustainable agriculture is the combination of reduced water requirements with enhanced ecosystem services. Currently, staple grains are obtained from annuals crops. A shift from annual to perennial crops has been suggested as a way to enhance ecosystem services. In fact, perennial plants, with their continuous soil cover and the higher allocation of resources to the below ground, contribute to the reduction of soil erosion and nutrient losses, while enhancing carbon sequestration in the root zone. Nevertheless, the net effect of a shift to perennial crops on water use for agriculture is still unknown, despite its relevance for the sustainability of such a shift. We explore here the implications for water management at the field- to farm-scale of a shift from annual to perennial crops, under rainfed and irrigated agriculture. A probabilistic description of the soil water balance and crop development is employed to quantify water requirements and yields and their inter-annual variability, as a function of rainfall patterns, soil and crop features. Optimal irrigation strategies are thus defined in terms of maximization of yield and minimization of required irrigation volumes and their inter-annual variability. The probabilistic model is parameterized based on an extensive meta-analysis of traits of co-generic annual and perennial species to explore the consequences for water requirements of shifting from annual to perennial crops under current and future climates. We show that the larger and more developed roots of perennial crops may allow a better exploitation of soil water resources and a reduction of yield variability with respect to annual species. At the same time, perennial

  11. CFD model of a spinning pipe gas lens

    CSIR Research Space (South Africa)

    Snedden, Glen C

    2006-07-01

    Full Text Available Slides on: Spinning Pipe Gas Lens; Focal Length; Refractive Index; Gas Dynamics; Guess at the gas dynamics; Density Profile; Flow Profile; Rosby Waves; Rayleigh–Taylor Instabilities...

  12. Population-level impact, herd immunity, and elimination after human papillomavirus vaccination: a systematic review and meta-analysis of predictions from transmission-dynamic models.

    Science.gov (United States)

    Brisson, Marc; Bénard, Élodie; Drolet, Mélanie; Bogaards, Johannes A; Baussano, Iacopo; Vänskä, Simopekka; Jit, Mark; Boily, Marie-Claude; Smith, Megan A; Berkhof, Johannes; Canfell, Karen; Chesson, Harrell W; Burger, Emily A; Choi, Yoon H; De Blasio, Birgitte Freiesleben; De Vlas, Sake J; Guzzetta, Giorgio; Hontelez, Jan A C; Horn, Johannes; Jepsen, Martin R; Kim, Jane J; Lazzarato, Fulvio; Matthijsse, Suzette M; Mikolajczyk, Rafael; Pavelyev, Andrew; Pillsbury, Matthew; Shafer, Leigh Anne; Tully, Stephen P; Turner, Hugo C; Usher, Cara; Walsh, Cathal

    2016-11-01

    Modelling studies have been widely used to inform human papillomavirus (HPV) vaccination policy decisions; however, many models exist and it is not known whether they produce consistent predictions of population-level effectiveness and herd effects. We did a systematic review and meta-analysis of model predictions of the long-term population-level effectiveness of vaccination against HPV 16, 18, 6, and 11 infection in women and men, to examine the variability in predicted herd effects, incremental benefit of vaccinating boys, and potential for HPV-vaccine-type elimination. We searched MEDLINE and Embase for transmission-dynamic modelling studies published between Jan 1, 2009, and April 28, 2015, that predicted the population-level impact of vaccination on HPV 6, 11, 16, and 18 infections in high-income countries. We contacted authors to determine whether they were willing to produce new predictions for standardised scenarios. Strategies investigated were girls-only vaccination and girls and boys vaccination at age 12 years. Base-case vaccine characteristics were 100% efficacy and lifetime protection. We did sensitivity analyses by varying vaccination coverage, vaccine efficacy, and duration of protection. For all scenarios we pooled model predictions of relative reductions in HPV prevalence (RR prev ) over time after vaccination and summarised results using the median and 10th and 90th percentiles (80% uncertainty intervals [UI]). 16 of 19 eligible models from ten high-income countries provided predictions. Under base-case assumptions, 40% vaccination coverage and girls-only vaccination, the RR prev of HPV 16 among women and men was 0·53 (80% UI 0·46-0·68) and 0·36 (0·28-0·61), respectively, after 70 years. With 80% girls-only vaccination coverage, the RR prev of HPV 16 among women and men was 0·93 (0·90-1·00) and 0·83 (0·75-1·00), respectively. Vaccinating boys in addition to girls increased the RR prev of HPV 16 among women and men by 0·18 (0·13-0

  13. How to do Meta-Analysis using HLM software

    OpenAIRE

    Petscher, Yaacov

    2013-01-01

    This is a step-by-step presentation of how to run a meta-analysis using HLM software. Because it's a variance known model, it is not run through the GUI, but batch mode. These slides show how to prepare the data and run the analysis.

  14. A Meta-Analysis of Advance-Organizer Studies.

    Science.gov (United States)

    Stone, Carol Leth

    Long term studies of advance organizers (AO) were analyzed with Glass's meta-analysis technique. AO's were defined as bridges from reader's previous knowledge to what is to be learned. The results were compared with predictions from Ausubel's model of assimilative learning. The results of the study indicated that advance organizers were associated…

  15. A Meta-Analysis of Advanced Organizer Studies.

    Science.gov (United States)

    Stone, Carol Leth

    1983-01-01

    Twenty-nine reports yielding 112 studies were analyzed with Glass's meta-analysis technique, and results were compared with predictions from Ausubel's model of assimilative learning. Overall, advance organizers were shown to be associated with increased learning and retention of material to be learned. (Author)

  16. OHBM 2017: Practical intensity based meta-analysis

    OpenAIRE

    Maumet, Camille

    2017-01-01

    "Practical intensity-based meta-analysis" slides from my talk in the OHBM 2017 educational talk on Neuroimaging meta-analysis.http://www.humanbrainmapping.org/files/2017/ED Courses/Neuroimaging Meta-Analysis.pdf

  17. Meta-Analysis in Stata Using Gllamm

    Science.gov (United States)

    Bagos, Pantelis G.

    2015-01-01

    There are several user-written programs for performing meta-analysis in Stata (Stata Statistical Software: College Station, TX: Stata Corp LP). These include metan, metareg, mvmeta, and glst. However, there are several cases for which these programs do not suffice. For instance, there is no software for performing univariate meta-analysis with…

  18. Trial Sequential Methods for Meta-Analysis

    Science.gov (United States)

    Kulinskaya, Elena; Wood, John

    2014-01-01

    Statistical methods for sequential meta-analysis have applications also for the design of new trials. Existing methods are based on group sequential methods developed for single trials and start with the calculation of a required information size. This works satisfactorily within the framework of fixed effects meta-analysis, but conceptual…

  19. Bayesian Meta-Analysis of Coefficient Alpha

    Science.gov (United States)

    Brannick, Michael T.; Zhang, Nanhua

    2013-01-01

    The current paper describes and illustrates a Bayesian approach to the meta-analysis of coefficient alpha. Alpha is the most commonly used estimate of the reliability or consistency (freedom from measurement error) for educational and psychological measures. The conventional approach to meta-analysis uses inverse variance weights to combine…

  20. Statistical Power in Meta-Analysis

    Science.gov (United States)

    Liu, Jin

    2015-01-01

    Statistical power is important in a meta-analysis study, although few studies have examined the performance of simulated power in meta-analysis. The purpose of this study is to inform researchers about statistical power estimation on two sample mean difference test under different situations: (1) the discrepancy between the analytical power and…

  1. Modeling internal stress distributions in the human lens: can opponent theories coexist?

    Science.gov (United States)

    Belaidi, A; Pierscionek, B K

    2007-08-03

    The effects of material properties and equatorial stretching forces on the stress distribution and shape profile of human lenses were investigated to see whether support could be found for either or both current theories of accommodation. Finite element analysis was used to create models using shape parameters and material properties from published data. Models were constructed for two lenses of different ages. Material properties were varied to show differences between models with a single elastic modulus and those with different moduli for the cortex and the nucleus. Two levels of stretching forces were applied at the equator. Comparisons between experimental and model profiles were made, and stress distribution patterns were constructed. In all models, stretching produces a flattening in the peripheral curvature of the lens. In the younger lens, model and experimental results show that central curvature at some points is steeper for stretched than for unstretched profiles. In the older lens, gradients are flatter at all central points for stretched model and experimental profiles compared to the unstretched profile. In all models, there is a region of higher stress distribution within the lens that corresponds with the position of an inflection point that appears on the anterior surface and, in the older lens, also on the posterior surface. The results show that equatorial stretching forces can produce shape changes in support of both current theories of accommodation depending on the lens age, shape, and applied force.

  2. A novel rat contact lens model for Fusarium keratitis

    Science.gov (United States)

    Abou Shousha, Mohamed; Santos, Andrea Rachelle C.; Oechsler, Rafael A.; Iovieno, Alfonso; Maestre-Mesa, Jorge; Ruggeri, Marco; Echegaray, Jose J.; Dubovy, Sander R.; Perez, Victor L.; Miller, Darlene; Alfonso, Eduardo C.

    2013-01-01

    Purpose The aim of this study was to develop and characterize a new contact lens–associated fungal keratitis rat model and to assess the ability of non-invasive spectral-domain optical coherence tomography (SD-OCT) to detect pathological changes in vivo in fungal keratitis. Methods We used SD-OCT to image and measure the cornea of Sprague Dawley rats. Fusarium infection was initiated in the rat eye by fitting Fusarium solani–soaked contact lenses on the experimental eye, while the control animals received contact lenses soaked in sterile saline. The fungal infection was monitored with periodic slit-lamp examination and in vivo SD-OCT imaging of the rat eye, and confirmed by histology, counting of viable fungi in the infected rat cornea, and PCR with specific primers for Fusarium sp. Results We imaged and measured the rat cornea with SD-OCT. Custom-made contact lenses were developed based on the OCT measurements. Incubation of contact lenses in a F. solani suspension resulted in biofilm formation. We induced contact lens–associated Fusarium keratitis by fitting the rat eyes for 4 h with the Fusarium-contaminated contact lenses. The SD-OCT images of the cornea correlated well with the slit-lamp and histopathological results and clearly defined clinical signs of infection, namely, increased corneal thickening, loss of epithelial continuity, hyper-reflective areas representing infiltrates, and endothelial plaques characteristic of fungal infection. Moreover, in three cases, SD-OCT detected the infection without any clear findings on slit-lamp examination. Infection was confirmed with histological fungal staining, PCR, and microbiological culture positivity. Conclusions We developed a highly reproducible rat contact lens model and successfully induced contact lens–associated Fusarium keratitis in this model. The clinical presentation of contact lens–associated Fusarium keratitis in the rat model is similar to the human condition. SD-OCT is a valuable tool that

  3. Recombinant Tissue Plasminogen Activator Induces Neurological Side Effects Independent on Thrombolysis in Mechanical Animal Models of Focal Cerebral Infarction: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Mei-Xue Dong

    Full Text Available Recombinant tissue plasminogen activator (rtPA is the only effective drug approved by US FDA to treat ischemic stroke, and it contains pleiotropic effects besides thrombolysis. We performed a meta-analysis to clarify effect of tissue plasminogen activator (tPA on cerebral infarction besides its thrombolysis property in mechanical animal stroke.Relevant studies were identified by two reviewers after searching online databases, including Pubmed, Embase, and ScienceDirect, from 1979 to 2016. We identified 6, 65, 17, 12, 16, 12 and 13 comparisons reporting effect of endogenous tPA on infarction volume and effects of rtPA on infarction volume, blood-brain barrier, brain edema, intracerebral hemorrhage, neurological function and mortality rate in all 47 included studies. Standardized mean differences for continuous measures and risk ratio for dichotomous measures were calculated to assess the effects of endogenous tPA and rtPA on cerebral infarction in animals. The quality of included studies was assessed using the Stroke Therapy Academic Industry Roundtable score. Subgroup analysis, meta-regression and sensitivity analysis were performed to explore sources of heterogeneity. Funnel plot, Trim and Fill method and Egger's test were obtained to detect publication bias.We found that both endogenous tPA and rtPA had not enlarged infarction volume, or deteriorated neurological function. However, rtPA would disrupt blood-brain barrier, aggravate brain edema, induce intracerebral hemorrhage and increase mortality rate.This meta-analysis reveals rtPA can lead to neurological side effects besides thrombolysis in mechanical animal stroke, which may account for clinical exacerbation for stroke patients that do not achieve vascular recanalization with rtPA.

  4. Conducting Meta-Analysis Using SAS

    CERN Document Server

    Arthur, Winfried; Huffcutt, Allen I; Arthur, Winfred

    2001-01-01

    Conducting Meta-Analysis Using SAS reviews the meta-analysis statistical procedure and shows the reader how to conduct one using SAS. It presents and illustrates the use of the PROC MEANS procedure in SAS to perform the data computations called for by the two most commonly used meta-analytic procedures, the Hunter & Schmidt and Glassian approaches. This book serves as both an operational guide and user's manual by describing and explaining the meta-analysis procedures and then presenting the appropriate SAS program code for computing the pertinent statistics. The practical, step-by-step instru

  5. CrossFit Overview: Systematic Review and Meta-analysis.

    Science.gov (United States)

    Claudino, João Gustavo; Gabbett, Tim J; Bourgeois, Frank; Souza, Helton de Sá; Miranda, Rafael Chagas; Mezêncio, Bruno; Soncin, Rafael; Cardoso Filho, Carlos Alberto; Bottaro, Martim; Hernandez, Arnaldo Jose; Amadio, Alberto Carlos; Serrão, Julio Cerca

    2018-02-26

    CrossFit is recognized as one of the fastest growing high-intensity functional training modes in the world. However, scientific data regarding the practice of CrossFit is sparse. Therefore, the objective of this study is to analyze the findings of scientific literature related to CrossFit via systematic review and meta-analysis. Systematic searches of the PubMed, Web of Science, Scopus, Bireme/MedLine, and SciELO online databases were conducted for articles reporting the effects of CrossFit training. The systematic review followed the PRISMA guidelines. The Oxford Levels of Evidence was used for all included articles, and only studies that investigated the effects of CrossFit as a training program were included in the meta-analysis. For the meta-analysis, effect sizes (ESs) with 95% confidence interval (CI) were calculated and heterogeneity was assessed using a random-effects model. Thirty-one articles were included in the systematic review and four were included in the meta-analysis. However, only two studies had a high level of evidence at low risk of bias. Scientific literature related to CrossFit has reported on body composition, psycho-physiological parameters, musculoskeletal injury risk, life and health aspects, and psycho-social behavior. In the meta-analysis, significant results were not found for any variables. The current scientific literature related to CrossFit has few studies with high level of evidence at low risk of bias. However, preliminary data has suggested that CrossFit practice is associated with higher levels of sense of community, satisfaction, and motivation.

  6. MetaEasy: A Meta-Analysis Add-In for Microsoft Excel

    Directory of Open Access Journals (Sweden)

    Evangelos Kontopantelis

    2009-04-01

    Full Text Available Meta-analysis is a statistical methodology that combines or integrates the results ofseveral independent clinical trials considered by the analyst to be `combinable' (Huque1988. However, completeness and user-friendliness are uncommon both in specialisedmeta-analysis software packages and in mainstream statistical packages that have to relyon user-written commands. We implemented the meta-analysis methodology in an Mi-crosoft Excel add-in which is freely available and incorporates more meta-analysis models(including the iterative maximum likelihood and prole likelihood than are usually avail-able, while paying particular attention to the user-friendliness of the package.

  7. One-stage individual participant data meta-analysis models: estimation of treatment-covariate interactions must avoid ecological bias by separating out within-trial and across-trial information.

    Science.gov (United States)

    Hua, Hairui; Burke, Danielle L; Crowther, Michael J; Ensor, Joie; Tudur Smith, Catrin; Riley, Richard D

    2017-02-28

    Stratified medicine utilizes individual-level covariates that are associated with a differential treatment effect, also known as treatment-covariate interactions. When multiple trials are available, meta-analysis is used to help detect true treatment-covariate interactions by combining their data. Meta-regression of trial-level information is prone to low power and ecological bias, and therefore, individual participant data (IPD) meta-analyses are preferable to examine interactions utilizing individual-level information. However, one-stage IPD models are often wrongly specified, such that interactions are based on amalgamating within- and across-trial information. We compare, through simulations and an applied example, fixed-effect and random-effects models for a one-stage IPD meta-analysis of time-to-event data where the goal is to estimate a treatment-covariate interaction. We show that it is crucial to centre patient-level covariates by their mean value in each trial, in order to separate out within-trial and across-trial information. Otherwise, bias and coverage of interaction estimates may be adversely affected, leading to potentially erroneous conclusions driven by ecological bias. We revisit an IPD meta-analysis of five epilepsy trials and examine age as a treatment effect modifier. The interaction is -0.011 (95% CI: -0.019 to -0.003; p = 0.004), and thus highly significant, when amalgamating within-trial and across-trial information. However, when separating within-trial from across-trial information, the interaction is -0.007 (95% CI: -0.019 to 0.005; p = 0.22), and thus its magnitude and statistical significance are greatly reduced. We recommend that meta-analysts should only use within-trial information to examine individual predictors of treatment effect and that one-stage IPD models should separate within-trial from across-trial information to avoid ecological bias. © 2016 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd

  8. Physical Readiness Training: A Meta-Analysis

    National Research Council Canada - National Science Library

    Vickers, Jr, Ross R

    2007-01-01

    .... This meta-analysis of available PRT studies (k = 3) indicated that (a) Fitness gains in the PRT program were equal to the gains in traditional fitness programs, and (b) the injury rate (i.e., hazard ratio...

  9. Exercise and Bone Density: Meta-Analysis

    National Research Council Canada - National Science Library

    Kelley, George A; Sharpe-Kelley, Kristi

    2007-01-01

    .... Since no meta-analysis had existed using individual patient data (IPD) to examine the effects of exercise on BMD, our second two-year period of funding was devoted to examining the feasibility...

  10. A meta-analysis of the antiviral activity of the HBV-specific immunotherapeutic TG1050 confirms its value over a wide range of HBsAg levels in a persistent HBV pre-clinical model.

    Science.gov (United States)

    Kratzer, Roland; Sansas, Benoît; Lélu, Karine; Evlachev, Alexei; Schmitt, Doris; Silvestre, Nathalie; Inchauspé, Geneviève; Martin, Perrine

    2018-02-01

    Pre-clinical models mimicking persistent hepatitis B virus (HBV) expression are seldom, do not capture all features of a human chronic infection and due to their complexity, are subject to variability. We report a meta-analysis of seven experiments performed with TG1050, an HBV-targeted immunotherapeutic, 1 in an HBV-persistent mouse model based on the transduction of mice by an adeno-associated virus coding for an infectious HBV genome (AAV-HBV). To mimic the clinical diversity seen in HBV chronically infected patients, AAV-HBV transduced mice displaying variable HBsAg levels were treated with TG1050. Overall mean percentages of responder mice, displaying decrease in important clinical parameters i.e. HBV-DNA (viremia) and HBsAg levels, were 52% and 51% in TG1050 treated mice, compared with 8% and 22%, respectively, in untreated mice. No significant impact of HBsAg level at baseline on response to TG1050 treatment was found. TG1050-treated mice displayed a significant shorter Time to Response (decline in viral parameters) with an Hazard Ratio (HR) of 8.3 for viremia and 2.6 for serum HBsAg. The mean predicted decrease for TG1050-treated mice was 0.5 log for viremia and 0.8 log for HBsAg, at the end of mice follow-up, compared to no decrease for viremia and 0.3 log HBsAg decrease for untreated mice. For mice receiving TG1050, a higher decline of circulating viremia and serum HBsAg level over time was detected by interaction term meta-analysis with a significant treatment effect (p = 0.002 and pHBV-persistent model mimicking clinical situations.

  11. Using the International Classification of Functioning, Disability, and Health Model to Gain Perspective of the Benefits of Yoga in Stroke, Multiple Sclerosis, and Children to Inform Practice for Children with Cerebral Palsy: A Meta-Analysis.

    Science.gov (United States)

    Veneri, Diana; Gannotti, Mary; Bertucco, Matteo; Fournier Hillman, Sarah E

    2018-02-06

    Research pertaining to yoga and children with cerebral palsy (CP) is negligible. The primary purpose of this study was to determine the domains of the International Classification of Functioning, Disability, and Health (ICF) model and levels of evidence for yoga and adults with stroke and multiple sclerosis (MS), and children. A secondary purpose was to decide whether any inferences could be made for children with CP. This study included a meta-analysis. A systematic review was performed of yoga and said populations. Outcome measures were categorized according to the ICF model domains of body structures and function, activity, and quality of life. Effect sizes (ESs) were calculated by using Cohen's d. Since there were few commonalities among outcome measures and reporting of outcomes within and among diagnostic groups, direct comparisons of ESs were difficult. Hence, we chose to evaluate the impact of yoga as compared with the control group or other physical exercise by using a General Linear Mixed Model. There were 5 yoga studies with stroke, 15 with MS, and 12 with children. Studies with children used outcomes related to body structure and function, whereas those with stroke and MS used outcomes across all three domains of the ICF. ESs varied from negligible to medium for stroke, from negligible to large for MS and children. The findings of this meta-analysis indicate that yoga is no better or worse than other exercise modalities as a treatment intervention for adults with stroke and MS, and children. Group yoga classes are typically social environments that can contribute to increased physical progress and feelings that contribute to quality of life, which may benefit individuals with CP. More research on yoga and particularly in children and adults with CP would yield valuable information for creating effective and safe yoga programs with a rich array of benefits.

  12. Dividend Policy and Corporate Value (A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Tifani Titah Dwi Tyastari

    2017-07-01

    Full Text Available This study aimed to understand the effect of dividend policy on corporate value, as well as to examine and analyze the variation of result study on corporate value in Indonesia.Dividend Signaling Model was the grand theory used to explain the effect of dividend policy on corporate value. This study used meta-analysis approach with the sample were 70 researches in Indonesia, both the published and unpublished in 2007-2015. The result of this study, meta-analysis strengthens the findings of the previous study which stated that the dividend policy could increase the corporate value. The differences of the previous studies were due to the presence of moderation effect from the measurement model of corporate value and dividend corporate.

  13. On the Multilevel Nature of Meta-Analysis: A Tutorial, Comparison of Software Programs, and Discussion of Analytic Choices.

    Science.gov (United States)

    Pastor, Dena A; Lazowski, Rory A

    2018-01-01

    The term "multilevel meta-analysis" is encountered not only in applied research studies, but in multilevel resources comparing traditional meta-analysis to multilevel meta-analysis. In this tutorial, we argue that the term "multilevel meta-analysis" is redundant since all meta-analysis can be formulated as a special kind of multilevel model. To clarify the multilevel nature of meta-analysis the four standard meta-analytic models are presented using multilevel equations and fit to an example data set using four software programs: two specific to meta-analysis (metafor in R and SPSS macros) and two specific to multilevel modeling (PROC MIXED in SAS and HLM). The same parameter estimates are obtained across programs underscoring that all meta-analyses are multilevel in nature. Despite the equivalent results, not all software programs are alike and differences are noted in the output provided and estimators available. This tutorial also recasts distinctions made in the literature between traditional and multilevel meta-analysis as differences between meta-analytic choices, not between meta-analytic models, and provides guidance to inform choices in estimators, significance tests, moderator analyses, and modeling sequence. The extent to which the software programs allow flexibility with respect to these decisions is noted, with metafor emerging as the most favorable program reviewed.

  14. Spherical aberration correction with an in-lens N-fold symmetric line currents model.

    Science.gov (United States)

    Hoque, Shahedul; Ito, Hiroyuki; Nishi, Ryuji

    2018-04-01

    In our previous works, we have proposed N-SYLC (N-fold symmetric line currents) models for aberration correction. In this paper, we propose "in-lens N-SYLC" model, where N-SYLC overlaps rotationally symmetric lens. Such overlap is possible because N-SYLC is free of magnetic materials. We analytically prove that, if certain parameters of the model are optimized, an in-lens 3-SYLC (N = 3) doublet can correct 3rd order spherical aberration. By computer simulation, we show that the required excitation current for correction is less than 0.25 AT for beam energy 5 keV, and the beam size after correction is smaller than 1 nm at the corrector image plane for initial slope less than 4 mrad. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Wide-field schematic eye models with gradient-index lens.

    Science.gov (United States)

    Goncharov, Alexander V; Dainty, Chris

    2007-08-01

    We propose a wide-field schematic eye model, which provides a more realistic description of the optical system of the eye in relation to its anatomical structure. The wide-field model incorporates a gradient-index (GRIN) lens, which enables it to fulfill properties of two well-known schematic eye models, namely, Navarro's model for off-axis aberrations and Thibos's chromatic on-axis model (the Indiana eye). These two models are based on extensive experimental data, which makes the derived wide-field eye model also consistent with that data. A mathematical method to construct a GRIN lens with its iso-indicial contours following the optical surfaces of given asphericity is presented. The efficiency of the method is demonstrated with three variants related to different age groups. The role of the GRIN structure in relation to the lens paradox is analyzed. The wide-field model with a GRIN lens can be used as a starting design for the eye inverse problem, i.e., reconstructing the optical structure of the eye from off-axis wavefront measurements. Anatomically more accurate age-dependent optical models of the eye could ultimately help an optical designer to improve wide-field retinal imaging.

  16. A choice that matters? Simulation study on the impact of direct meta-analysis methods on health economic outcomes

    NARCIS (Netherlands)

    Vemer, Pepijn; Al, Maiwenn J.; Oppe, Mark; Rutten-van Molken, Maureen P. M. H.

    Decision-analytic cost-effectiveness (CE) models combine many different parameters like transition probabilities, event probabilities, utilities and costs, which are often obtained after meta-analysis. The method of meta-analysis may affect the CE estimate. Our aim was to perform a simulation study

  17. The Big Five Personality Traits, Big Two Metatraits and Social Media: A Meta-Analysis

    OpenAIRE

    Campbell, William

    2016-01-01

    This article reports a meta-analysis of the relationships between social network site use and the Big Five personality traits (openness, conscientiousness, extraversion, agreeableness, and neuroticism) as well as the Big Two metatraits (plasticity and stability). A random effect meta-analysis model was used to calculate the meta-results of Big Five. Extraversion and openness were the strongest predictors of SNS activities, while conscientiousness, neuroticism, and agreeableness only correlate...

  18. Prevalence of Depression among University Students: A Systematic Review and Meta-Analysis Study

    OpenAIRE

    Sarokhani, Diana; Delpisheh, Ali; Veisani, Yousef; Sarokhani, Mohamad Taher; Manesh, Rohollah Esmaeli; Sayehmiri, Kourosh

    2013-01-01

    Introduction. Depression is one of the four major diseases in the world and is the most common cause of disability from diseases. The aim of this study is to estimate the prevalence of depression among Iranian university students using meta-analysis method. Materials and Methods. Keyword depression was searched in electronic databases such as PubMed, Scopus, MAGIran, Medlib, and SID. Data was analyzed using meta-analysis (random-effects model). Heterogeneity of studies was assessed using ...

  19. Lucid dreaming incidence: a quality effects meta-analysis\\ud of 50 years of research

    OpenAIRE

    Saunders, David; Roe, Chris A; Smith, G D; Clegg, Helen

    2016-01-01

    We report a quality effects meta-analysis on studies from the period 1966–2016 measuring either (a) lucid dreaming prevalence (one or more lucid dreams in a lifetime); (b) frequent lucid dreaming (one or more lucid dreams in a month) or both. A quality effects meta-analysis allows for the minimisation of the influence of study methodological quality on overall model estimates. Following sensitivity analysis, a heterogeneous lucid dreaming prevalence data set of 34 studies yielded a mean estim...

  20. A Meta-Analysis of Risky Sexual Behaviour among Male Youth in Developing Countries

    OpenAIRE

    Berhan, Yifru; Berhan, Asres

    2015-01-01

    The purpose of this meta-analysis was to assess the association between risky sexual behaviour and level of education and economic status in male youth. Previous tests of the association of risky sexual behaviour with levels of education and economic status have yielded inconsistent results. Using data from 26 countries, from both within and outside Africa, we performed a meta-analysis with a specific focus on male youths’ risky sexual behaviour. We applied a random effects analytic model and...

  1. The influence of stereotype threat on immigrants: review and meta-analysis

    OpenAIRE

    Appel, Markus; Weber, Silvana; Kronberger, Nicole

    2015-01-01

    In many regions around the world students with certain immigrant backgrounds underachieve in educational settings. This paper provides a review and meta-analysis on one potential source of the immigrant achievement gap: stereotype threat, a situational predicament that may prevent students to perform up to their full abilities. A meta-analysis of 19 experiments suggests an overall mean effect size of 0.63 (random effects model) in support of stereotype threat theory. The results are complemen...

  2. Advances in meta-analysis: examples from internal medicine to neurology.

    Science.gov (United States)

    Copetti, Massimiliano; Fontana, Andrea; Graziano, Giusi; Veneziani, Federica; Siena, Federica; Scardapane, Marco; Lucisano, Giuseppe; Pellegrini, Fabio

    2014-01-01

    We review the state of the art in meta-analysis and data pooling following the evolution of the statistical models employed. Starting from a classic definition of meta-analysis of published data, a set of apparent antinomies which characterized the development of the meta-analytic tools are reconciled in dichotomies where the second term represents a possible generalization of the first one. Particular attention is given to the generalized linear mixed models as an overall framework for meta-analysis. Bayesian meta-analysis is discussed as a further possibility of generalization for sensitivity analysis and the use of priors as a data augmentation approach. We provide relevant examples to underline how the need for adequate methods to solve practical issues in specific areas of research have guided the development of advanced methods in meta-analysis. We show how all the advances in meta-analysis naturally merge into the unified framework of generalized linear mixed models and reconcile apparently conflicting approaches. All these complex models can be easily implemented with the standard commercial software available. © 2013 S. Karger AG, Basel.

  3. A bunswik lens model of consumer health judgments of packaged foods

    DEFF Research Database (Denmark)

    Orquin, Jacob Lund

    2014-01-01

    criterion was calculated for each product according to its specific nutrition values using a validated nutrition profile. The lens model included explicit cues such as nutrition values, nutrition and health claims, food category, and brand and implicit cues such a packaging design and category......Consumer health judgments of packaged food were compared with an objective healthfulness criterion using a Brunswik lens model. Consumer judgments were obtained from a representative consumer sample (N= 1329) who evaluated the healthfulness of 198 packaged food products. The objective healthfulness...

  4. Meta Analisis Model Pembelajaran Problem Based Learning dalam Meningkatkan Keterampilan Berpikir Kritis di Sekolah Dasar [A Meta-analysis of Problem-Based Learning Models in Increasing Critical Thinking Skills in Elementary Schools

    Directory of Open Access Journals (Sweden)

    Indri Anugraheni

    2018-01-01

    Full Text Available This study aims to analyze Problem-based Learning models intended to improve critical thinking skills in elementary school students. Problem-based learning models are learning processes where students are open minded, reflexive, active, reflective, and critical through real-world context activities. In this study the researcher used a meta-analysis method. First, the researcher formulated the research problem, then proceeded to review the existing relevant research for analysis. Data were collected by using a non-test technique by browsing electronic journals through Google Scholar and studying documentation in the library. Seven articles were found through Google Scholar and only one was found in the library. Based on the analysis of the results, the problem-based learning model can improve students' thinking ability from as little as 2.87% up to 33.56% with an average of 14.18%. BAHASA INDONESIA ABSTRAK: Penelitian ini bertujuan untuk menganalisis kembali tentang model pembelajaran Problem Based Learning untuk meningkatkan keterampilan berpikir kritis di Sekolah Dasar. Model pembelajaran Problem Based Learning adalah proses pembelajaran dimana siswa mampu memiliki pola pikir yang terbuka, refktif, aktif, reflektif dan kritis melalui kegiatan konteks dunia nyata. Dalam penelitian ini peneliti menggunakan metode meta analisis. Pertama-tama, peneliti merumuskan masalah penelitian, kemudian dilanjutkan dengan menelusuri penelitian yang sudah ada dan relevan untuk dianalisis. Teknik pengumpulan data dengan menggunakan non tes yaitu dengan menelusuri jurnal elektronik melalui google Cendekia dan studi dokumentasi di perpustakaan. Dari hasil penelusuran diperoleh 20 artikel dari jurnal dan 3 dari repository. Berdasarkan hasil analisis ternyata model pembelajaran Problem Based Learning mampu meningkatkan kemampuan berpikir Siswa mulai dari yang terendah 2,87% sampai yang tertinggi 33,56% dengan rata-rata 12,73%.

  5. Immunotherapy in advanced melanoma: a network meta-analysis.

    Science.gov (United States)

    Pyo, Jung-Soo; Kang, Guhyun

    2017-05-01

    The aim of this study was to compare the effects of various immunotherapeutic agents and chemotherapy for unresected or metastatic melanomas. We performed a network meta-analysis using a Bayesian statistical model to compare objective response rate (ORR) of various immunotherapies from 12 randomized controlled studies. The estimated ORRs of immunotherapy and chemotherapy were 0.224 and 0.108, respectively. The ORRs of immunotherapy in untreated and pretreated patients were 0.279 and 0.176, respectively. In network meta-analysis, the odds ratios for ORR of nivolumab (1 mg/kg)/ipilmumab (3 mg/kg), pembrolizumab 10 mg/kg and nivolumab 3 mg/kg were 8.54, 5.39 and 4.35, respectively, compared with chemotherapy alone. Our data showed that various immunotherapies had higher ORRs rather than chemotherapy alone.

  6. Road safety effects of roundabouts: A meta-analysis.

    Science.gov (United States)

    Elvik, Rune

    2017-02-01

    This paper presents a meta-analysis of the road safety effects of converting junctions to roundabouts. 44 studies containing a total of 154 estimates of effect were included. Based on a meta-regression analysis, converting junctions to roundabouts is associated with a reduction of fatal accidents of about 65% and a reduction of injury accidents of about 40%. The mean effect on property-damage-only accidents is ambiguous. Summary estimates of effect are robust for fatal and injury accidents, but vary depending on the model of meta-analysis and the treatment of outlying data points for property-damage-only accidents. A trim-and-fill analysis suggests a weak tendency for publication bias, with modest influence on summary estimates of effect. It is concluded that roundabouts are very effective in reducing traffic fatalities. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Association between circadian preference and academic achievement: A systematic review and meta-analysis.

    Science.gov (United States)

    Tonetti, Lorenzo; Natale, Vincenzo; Randler, Christoph

    2015-01-01

    The association between circadian preference and academic achievement has been assessed through a systematic review and meta-analysis. The literature searches retrieved 1647 studies; 31 studies, with a total sample size of 27 309 participants, fulfilled the inclusion criteria and were included in the meta-analysis. With reference to all these 31 studies, before running the meta-analysis, the sign of the correlation between the investigated variables was set in a way that a positive correlation showed that eveningness was related to worse academic performance. The meta-analysis yielded a small overall effect size of 0.143 (CI [0,129; 0,156]) under a fixed effects model (Z = 20.584, p academic performance, both in school pupils and university students; for the first time, it has been shown that such relationship changes over time, being weaker in university students.

  8. Induced abortion rate in Iran: a meta-analysis.

    Science.gov (United States)

    Motaghi, Zahra; Poorolajal, Jalal; Keramat, Afsaneh; Shariati, Mohammad; Yunesian, Masud; Masoumi, Seyyedeh Zahra

    2013-10-01

    About 44 million induced abortions take place worldwide annually, of which 50% are unsafe. The results of studies investigated the induced abortion rate in Iran are inconsistent. The aim of this meta-analysis was to estimate the incidence rate of induced abortion in Iran. National and international electronic databases, as well as conference databases until July 2012 were searched. Reference lists of articles were screened and the studies' authors were contacted for additional unpublished studies. Cross-sectional studies addressing induced abortion in Iran were included in this meta-analysis. The primary outcome of interest was the induced abortion rate (the number of abortions per 1000 women aged 15-44 years in a year) or the ratio (the number of abortions per 100 live births in a year). The secondary outcome of interest was the prevalence of unintended pregnancies (the number of mistimed, unplanned, or unwanted pregnancies per total pregnancies). Data were analyzed using random effect models. Of 603 retrieved studies, using search strategy, 10 studies involving 102,394 participants were eventually included in the meta-analysis. The induced abortion rate and ratio were estimated as 8.9 per 1000 women aged 15-44 years (95% CI: 5.46, 12.33) and 5.34 per 100 live births (95% CI: 3.61, 7.07), respectively. The prevalence of unintended pregnancy was estimated as 27.94 per 100 pregnant women (95% CI: 23.46, 32.42). The results of this meta-analysis helped a better understanding of the incidence of induced abortion in Iran compared to the other developing countries in Asia. However, additional sources of data on abortion other than medical records and survey studies are needed to estimate the true rate of unsafe abortion in Iran.

  9. A quasi-2-dimensional model for respiration of the cornea with soft contact lens wear.

    Science.gov (United States)

    Takatori, Sho C; Radke, Clayton J

    2012-04-01

    Because neither the human cornea nor a soft contact lens (SCL) is of constant thickness, corneal oxygenation varies locally. To quantify the importance of cornea/SCL thickness variations on oxygen demand, we develop a quasi-2-dimensional (2D) respiration model that accounts for aerobic and anaerobic metabolism and bicarbonate buffering. Because metabolism is critical to oxygen demand, we extend the 1-dimensional (1D), 6-layer oxygen metabolic model of Chhabra et al. Lateral diffusion is shown to be negligible. Accordingly, we adopt the 1D reactive-diffusion metabolic model but apply it locally along the cornea/lens extent. This "quasi-2D" approximation permits 2D assessment of oxygen consumption, including the effects of carbon dioxide, glucose, and lactate, bicarbonate, and hydrogen ions. We use both an oxygen deficiency factor and an excess lactate factor to gauge corneal health after accounting for both cornea and contact lens thickness variations. The quasi-2D respiration model provides quantitative spatial resolution of corneal oxygenation with minimal expenditure of computation time. When only aerobic oxygen loss is included, our quasi-2D approach is in excellent agreement with the fully 2D results of Alvord et al. However, the quasi-2D model predicts 2D concentration profiles of glucose, lactate ions, bicarbonate ions, hydrogen ions, and carbon dioxide, as well as oxygen. Neglect of metabolic reactions and/or thickness variations leads to inaccurate prediction of oxygen demand, especially near the lens periphery. The quasi-2D respiration model indicates that lateral thickness variations and respiration kinetics are critical for assessing on-eye physiologic performance of an SCL. We find that oxygen deficiency factor and excess lactate factor are useful indices to gauge corneal hypoxia. A user-friendly computer program of the quasi-2D respiration model is available for lens design.

  10. Meta-Analyst: software for meta-analysis of binary, continuous and diagnostic data

    Directory of Open Access Journals (Sweden)

    Schmid Christopher H

    2009-12-01

    Full Text Available Abstract Background Meta-analysis is increasingly used as a key source of evidence synthesis to inform clinical practice. The theory and statistical foundations of meta-analysis continually evolve, providing solutions to many new and challenging problems. In practice, most meta-analyses are performed in general statistical packages or dedicated meta-analysis programs. Results Herein, we introduce Meta-Analyst, a novel, powerful, intuitive, and free meta-analysis program for the meta-analysis of a variety of problems. Meta-Analyst is implemented in C# atop of the Microsoft .NET framework, and features a graphical user interface. The software performs several meta-analysis and meta-regression models for binary and continuous outcomes, as well as analyses for diagnostic and prognostic test studies in the frequentist and Bayesian frameworks. Moreover, Meta-Analyst includes a flexible tool to edit and customize generated meta-analysis graphs (e.g., forest plots and provides output in many formats (images, Adobe PDF, Microsoft Word-ready RTF. The software architecture employed allows for rapid changes to be made to either the Graphical User Interface (GUI or to the analytic modules. We verified the numerical precision of Meta-Analyst by comparing its output with that from standard meta-analysis routines in Stata over a large database of 11,803 meta-analyses of binary outcome data, and 6,881 meta-analyses of continuous outcome data from the Cochrane Library of Systematic Reviews. Results from analyses of diagnostic and prognostic test studies have been verified in a limited number of meta-analyses versus MetaDisc and MetaTest. Bayesian statistical analyses use the OpenBUGS calculation engine (and are thus as accurate as the standalone OpenBUGS software. Conclusion We have developed and validated a new program for conducting meta-analyses that combines the advantages of existing software for this task.

  11. Meta-Analyst: software for meta-analysis of binary, continuous and diagnostic data.

    Science.gov (United States)

    Wallace, Byron C; Schmid, Christopher H; Lau, Joseph; Trikalinos, Thomas A

    2009-12-04

    Meta-analysis is increasingly used as a key source of evidence synthesis to inform clinical practice. The theory and statistical foundations of meta-analysis continually evolve, providing solutions to many new and challenging problems. In practice, most meta-analyses are performed in general statistical packages or dedicated meta-analysis programs. Herein, we introduce Meta-Analyst, a novel, powerful, intuitive, and free meta-analysis program for the meta-analysis of a variety of problems. Meta-Analyst is implemented in C# atop of the Microsoft .NET framework, and features a graphical user interface. The software performs several meta-analysis and meta-regression models for binary and continuous outcomes, as well as analyses for diagnostic and prognostic test studies in the frequentist and Bayesian frameworks. Moreover, Meta-Analyst includes a flexible tool to edit and customize generated meta-analysis graphs (e.g., forest plots) and provides output in many formats (images, Adobe PDF, Microsoft Word-ready RTF). The software architecture employed allows for rapid changes to be made to either the Graphical User Interface (GUI) or to the analytic modules.We verified the numerical precision of Meta-Analyst by comparing its output with that from standard meta-analysis routines in Stata over a large database of 11,803 meta-analyses of binary outcome data, and 6,881 meta-analyses of continuous outcome data from the Cochrane Library of Systematic Reviews. Results from analyses of diagnostic and prognostic test studies have been verified in a limited number of meta-analyses versus MetaDisc and MetaTest. Bayesian statistical analyses use the OpenBUGS calculation engine (and are thus as accurate as the standalone OpenBUGS software). We have developed and validated a new program for conducting meta-analyses that combines the advantages of existing software for this task.

  12. Mass meta-analysis in Talairach space

    DEFF Research Database (Denmark)

    Nielsen, Finn Årup

    2004-01-01

    We provide a method for mass meta-analysis in a neuroinformatics database containing stereotaxic Talairach coordinates from neuroimaging experiments. Database labels are used to group the individual experiments, e.g., according to cognitive function, and the consistent pattern of the experiments...... of experiments, and the distances to the null hypotheses are used to sort the voxels across groups of experiments. This allows for mass meta-analysis, with the construction of a list with the most prominent associations between brain areas and group labels. Furthermore, the method can be used for functional...

  13. Determinants of investment behaviour. Methods and applications of meta-analysis

    International Nuclear Information System (INIS)

    Koetse, M.J.

    2006-01-01

    Meta-analysis is gradually gaining ground in economics as a research method to objectively and quantitatively summarise a body of existing empirical evidence. This dissertation studies the performance of well-known meta-analytic models and presents two meta-analysis applications. Despite its many attractive features, meta-analysis faces several methodical difficulties, especially when applied in economic research. We investigate two specific methodical problems that any meta-analysis in economics will have to deal with, viz., systematic effect-size variation due to primary-study misspecifications, and random effect-size heterogeneity. Using Monte-Carlo analysis we investigate the effects of these methodical problems on the results of a meta-analysis, and study the small-sample properties of several well-known and often applied meta-estimators. The focus of the meta-analysis applications is on two topics that are relevant for understanding investment behaviour, viz., the impact of uncertainty on investment spending, and the potential for substitution of capital for energy in production processes. In the first application we aim to shed light on the direction of the relationship between investment and uncertainty, and to uncover which factors are empirically relevant for explaining the wide variety in study outcomes. In the second application our goal is to analyse the direction and magnitude of capital-energy substitution potential, and to analyse the empirical relevance of suggested sources of variation in elasticity estimates

  14. Modeling of a Variable Focal Length Flat Lens Using Left Handed Metamaterials

    Science.gov (United States)

    Reinert, Jason

    2004-01-01

    Left Handed Metamaterials (LHM) were originally purposed by Victor Veselago in1968. These substances would allow a flat structure to focus electromagnetic (EM) waves because they have a negative index of refraction. A similar structure made from conventional materials, those with a positive index of refraction, would disperse the waves. But until recently, these structures have been purely theoretical because substances with both a negative permittivity and negative permeability, material properties necessary for a negative index of refraction, do not naturally exist, Recent developments have produced a structure composed of an array of thin wires and split ring resonators that shows a negative index of refraction. area smaller than a square wavelength. How small the area is can be determined by how perfectly the lens is polished and how pure the substance is that composes the lens. These lenses must also be curved for focusing to occur. The focal length is determined by the curvature of the lens and the material. On the other hand, a flat structure made from LHM would focus light because of the effect of a negative index of refraction in Snell s law. The focal length could also be varied by simply adjusting the distance of the lens from the source of radiation. This could create many devices that are adjustable to different situations in fields such as biomedical imaging and communication. the software package XFDTD which solves Maxwell s equations in the frequency domain as well as the time domain. The program used Drude models of materials to simulate the effect of negative permittivity and negative permeability. Because of this, a LHM can be simulated as a solid block of material instead of an array of wires and split ring resonators. After a flat lens is formed, I am to examine the focusing effect of the lens and determine if a higher resolution flat lens can be developed. Traditional lenses made from conventional materials cannot focus an EM wave onto an My

  15. Systematic review and meta-analysis of studies evaluating diagnostic test accuracy: A practical review for clinical researchers-Part II. general guidance and tips

    International Nuclear Information System (INIS)

    Kim, Kyung Won; Choi, Sang Hyun; Huh, Jimi; Park, Seong Ho; Lee, June Young

    2015-01-01

    Meta-analysis of diagnostic test accuracy studies differs from the usual meta-analysis of therapeutic/interventional studies in that, it is required to simultaneously analyze a pair of two outcome measures such as sensitivity and specificity, instead of a single outcome. Since sensitivity and specificity are generally inversely correlated and could be affected by a threshold effect, more sophisticated statistical methods are required for the meta-analysis of diagnostic test accuracy. Hierarchical models including the bivariate model and the hierarchical summary receiver operating characteristic model are increasingly being accepted as standard methods for meta-analysis of diagnostic test accuracy studies. We provide a conceptual review of statistical methods currently used and recommended for meta-analysis of diagnostic test accuracy studies. This article could serve as a methodological reference for those who perform systematic review and meta-analysis of diagnostic test accuracy studies

  16. Systematic review with meta-analysis

    DEFF Research Database (Denmark)

    Kimer, N; Krag, A; Møller, Søren

    2014-01-01

    BACKGROUND: Rifaximin is recommended for prevention of hepatic encephalopathy (HE). The effects of rifaximin on overt and minimal HE are debated. AIM: To perform a systematic review and meta-analysis of randomised controlled trials (RCTs) on rifaximin for HE. METHODS: We performed electronic...

  17. Incorporating Quality Scores in Meta-Analysis

    Science.gov (United States)

    Ahn, Soyeon; Becker, Betsy Jane

    2011-01-01

    This paper examines the impact of quality-score weights in meta-analysis. A simulation examines the roles of study characteristics such as population effect size (ES) and its variance on the bias and mean square errors (MSEs) of the estimators for several patterns of relationship between quality and ES, and for specific patterns of systematic…

  18. Wind power externalities: A meta-analysis

    NARCIS (Netherlands)

    Mattmann, M.; Logar, I.; Brouwer, R.

    2016-01-01

    This study presents the first quantitative meta-analysis of the non-market valuation literature on the external effects associated with wind power production. A data set of 60 observations drawn from 32 studies is constructed. The relative economic values of different types of externalities as well

  19. Cost-effectiveness of two versus three or more doses of intermittent preventive treatment for malaria during pregnancy in sub-Saharan Africa: a modelling study of meta-analysis and cost data.

    Science.gov (United States)

    Fernandes, Silke; Sicuri, Elisa; Kayentao, Kassoum; van Eijk, Anne Maria; Hill, Jenny; Webster, Jayne; Were, Vincent; Akazili, James; Madanitsa, Mwayi; ter Kuile, Feiko O; Hanson, Kara

    2015-03-01

    In 2012, WHO changed its recommendation for intermittent preventive treatment of malaria during pregnancy (IPTp) from two doses to monthly doses of sulfadoxine-pyrimethamine during the second and third trimesters, but noted the importance of a cost-effectiveness analysis to lend support to the decision of policy makers. We therefore estimated the incremental cost-effectiveness of IPTp with three or more (IPTp-SP3+) versus two doses of sulfadoxine-pyrimethamine (IPTp-SP2). For this analysis, we used data from a 2013 meta-analysis of seven studies in sub-Saharan Africa. We developed a decision tree model with a lifetime horizon. We analysed the base case from a societal perspective. We did deterministic and probabilistic sensitivity analyses with appropriate parameter ranges and distributions for settings with low, moderate, and high background risk of low birthweight, and did a separate analysis for HIV-negative women. Parameters in the model were obtained for all countries included in the original meta-analysis. We did simulations in hypothetical cohorts of 1000 pregnant women receiving either IPTp-SP3+ or IPTp-SP2. We calculated disability-adjusted life-years (DALYs) for low birthweight, severe to moderate anaemia, and clinical malaria. We calculated cost estimates from data obtained in observational studies, exit surveys, and from public procurement databases. We give financial and economic costs in constant 2012 US$. The main outcome measure was the incremental cost per DALY averted. The delivery of IPTp-SP3+ to 1000 pregnant women averted 113·4 DALYs at an incremental cost of $825·67 producing an incremental cost-effectiveness ratio (ICER) of $7·28 per DALY averted. The results remained robust in the deterministic sensitivity analysis. In the probabilistic sensitivity analyses, the ICER was $7·7 per DALY averted for moderate risk of low birthweight, $19·4 per DALY averted for low risk, and $4·0 per DALY averted for high risk. The ICER for HIV

  20. Meta-Analysis at Middle Age: A Personal History

    Science.gov (United States)

    Glass, Gene V.

    2015-01-01

    The 40-year history of meta-analysis is traced from the vantage point of one of its originators. Research syntheses leading to the first examples of meta-analysis are identified. Early meta-analyses of the literature on psychotherapy outcomes and school class size are recounted. The influence on the development of meta-analysis of several…

  1. A method of LED free-form tilted lens rapid modeling based on scheme language

    Science.gov (United States)

    Dai, Yidan

    2017-10-01

    According to nonimaging optical principle and traditional LED free-form surface lens, a new kind of LED free-form tilted lens was designed. And a method of rapid modeling based on Scheme language was proposed. The mesh division method was applied to obtain the corresponding surface configuration according to the character of the light source and the desired energy distribution on the illumination plane. Then 3D modeling software and the Scheme language programming are used to generate lens model respectively. With the help of optical simulation software, a light source with the size of 1mm*1mm*1mm in volume is used in experiment, and the lateral migration distance of illumination area is 0.5m, in which total one million rays are computed. We could acquire the simulated results of both models. The simulated output result shows that the Scheme language can prevent the model deformation problems caused by the process of the model transfer, and the degree of illumination uniformity is reached to 82%, and the offset angle is 26°. Also, the efficiency of modeling process is greatly increased by using Scheme language.

  2. Modelling the evaporation of a tear film over a contact lens.

    Science.gov (United States)

    Talbott, Kevin; Xu, Amber; Anderson, Daniel M; Seshaiyer, Padmanabhan

    2015-06-01

    A contact lens (CL) separates the tear film into a pre-lens tear film (PrLTF), the fluid layer between the CL and the outside environment, and a post-lens tear film (PoLTF), the fluid layer between the CL and the cornea. We examine a model for evaporation of a PrLTF on a modern permeable CL allowing fluid transfer between the PrLTF and the PoLTF. Evaporation depletes the PrLTF, and continued evaporation causes depletion of the PoLTF via fluid loss through the CL. Governing equations include Navier-Stokes, heat and Darcy's equations for the fluid flow and heat transfer in the PrLTF and porous layer. The PoLTF is modelled by a fixed pressure condition on the posterior surface of the CL. The original model is simplified using lubrication theory for the PrLTF and CL applied to a sagittal plane through the eye. We obtain a partial differential equation (PDE) for the PrLTF thickness that is first-order in time and fourth-order in space. This model incorporates evaporation, conjoining pressure effects in the PrLTF, capillarity and heat transfer. For a planar film, we find that this PDE can be reduced to an ordinary differential equation (ODE) that can be solved analytically or numerically. This reduced model allows for interpretation of the various system parameters and captures most of the basic physics contained in the model. Comparisons of ODE and PDE models, including estimates for the loss of fluid through the lens due to evaporation, are given. © The Authors 2014. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  3. Oxidative stress of crystalline lens in rat menopausal model

    OpenAIRE

    Acer, Semra; Pekel, Gökhan; Küçükatay, Vural; Karabulut, Aysun; Yağcı, Ramazan; Çetin, Ebru Nevin; Akyer, Şahika Pınar; Şahin, Barbaros

    2016-01-01

    ABSTRACT Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Gro...

  4. Comparison of Robotic Surgery with Laparoscopy and Laparotomy for Treatment of Endometrial Cancer: A Meta-Analysis

    OpenAIRE

    Ran, Longke; Jin, Jing; Xu, Yan; Bu, Youquan; Song, Fangzhou

    2014-01-01

    Purpose To compare the relative merits among robotic surgery, laparoscopy, and laparotomy for patients with endometrial cancer by conducting a meta-analysis. Methods The MEDLINE, Embase, PubMed, Web of Science, and Cochrane Library databases were searched. Studies clearly documenting a comparison between robotic surgery and laparoscopy or between robotic surgery and laparotomy for endometrial cancer were selected. The outcome measures included operating time (OT), number of complications, len...

  5. Excessive weight gain during pregnancy and risk of macrosomia: a meta-analysis.

    Science.gov (United States)

    Tian, Chaoqing; Hu, Chengwen; He, Xiujie; Zhu, Meng; Qin, Fengyun; Liu, Yue; Hu, Chuanlai

    2016-01-01

    This meta-analysis aimed to estimate the relation between excessive gestational weight gain and macrosomia. We performed a meta-analysis by searching PubMed, EMBASE and the Cochrane library for English-language literature from inception to 1 October 2014. Studies assessing the relationship between excessive gestational weight gain and macrosomia were included. Characteristics including study design, country, sample size, definition of macrosomia, adjusted odds ratios, CIs and adjustment factors were extracted independently by two reviewers. Summary odds ratios were calculated by using a random-effects model meta-analysis. 15 relevant articles were eligible for the meta-analysis. Incorporated by random-effect model before the heterogeneity tests, the value of OR was 2.35 (95 % CI: 1.95, 2.85). Stratified analysis showed no differences regarding different study design, definition of macrosomia and location of study. There was no indication of a publication bias either from the result of Egger's test (P = 0.572) or Begg's test (P = 0.572). Our meta-analysis indicated that excessive gestational weight gain might increase the risk of macrosomia.

  6. Hyperelastic modelling of the crystalline lens: Accommodation and presbyopia

    Directory of Open Access Journals (Sweden)

    Elena Lanchares

    2012-07-01

    Conclusions: In agreement with the classical theory of Helmholtz, on which we based our model, our results indicate that a major cause of presbyopia is that both nucleus and cortex become stiffer with age; therefore, a constant value of the zonular forces with aging does not achieve full accommodation, that is, the accommodation capability decreases.

  7. Antioxidative role of ocular melanin pigment in the model of lens induced uveitis.

    Science.gov (United States)

    Bilgihan, A; Bilgihan, M K; Akata, R F; Aricioğlu, A; Hasanreisoğlu, B

    1995-12-01

    Ocular melanin pigment has antioxidant effect against excess of dispersed light. To investigate whether it has a similar effect in ocular inflammations, we used albino and pigmented guinea pigs and measured retinal glutathione peroxidase activities and lipid peroxide levels (expressed as thiobarbituric acid reactive substances) in a model of lens induced uveitis. Although the increase in the levels of the retinal lipid peroxides were higher in the albino group (204%, p < 0.05), the decrease in the activities of glutathione peroxidase were higher in pigmented guinea pigs (26%, p < 0.005). The results of the study suggest that pigmentless animals are more sensitive to the ocular inflammations, and ocular melanin pigment may act as an endojen antioxidant in lens induced uveitis.

  8. Toxocariasis and epilepsy: systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Graziella Quattrocchi

    Full Text Available OBJECTIVE: Human toxocariasis is a zoonotic infection caused by the larval stages of Toxocara canis (T. canis and less frequently Toxocara cati (T. cati. A relationship between toxocariasis and epilepsy has been hypothesized. We conducted a systematic review and a meta-analysis of available data to evaluate the strength of association between epilepsy and Toxocara spp. seropositivity and to propose some guidelines for future surveys. DATA SOURCES: Electronic databases, the database from the Institute of Neuroepidemiology and Tropical Neurology of the University of Limoges (http://www-ient.unilim.fr/ and the reference lists of all relevant papers and books were screened up to October 2011. METHODS: We performed a systematic review of literature on toxocariasis (the exposure and epilepsy (the outcome. Two authors independently assessed eligibility and study quality and extracted data. A common odds ratio (OR was estimated using a random-effects meta-analysis model of aggregated published data. RESULTS: Seven case-control studies met the inclusion criteria, for a total of 1867 participants (850 cases and 1017 controls. The percentage of seropositivity (presence of anti-Toxocara spp. antibodies was higher among people with epilepsy (PWE in all the included studies even if the association between epilepsy and Toxocara spp. seropositivity was statistically significant in only 4 studies, with crude ORs ranging 2.04-2.85. Another study bordered statistical significance, while in 2 of the included studies no significant association was found. A significant (p < 0.001 common OR of 1.92 [95% confidence interval (CI 1.50-2.44] was estimated. Similar results were found when meta-analysis was restricted to the studies considering an exclusively juvenile population and to surveys using Western Blot as confirmatory or diagnostic serological assay. CONCLUSION: Our results support the existence of a positive association between Toxocara spp. seropositivity and

  9. Pooling, meta-analysis, and the evaluation of drug safety

    Directory of Open Access Journals (Sweden)

    Leizorovicz Alain

    2002-03-01

    Full Text Available Abstract Background The "integrated safety report" of the drug registration files submitted to health authorities usually summarizes the rates of adverse events observed for a new drug, placebo or active control drugs by pooling the safety data across the trials. Pooling consists of adding the numbers of events observed in a given treatment group across the trials and dividing the results by the total number of patients included in this group. Because it considers treatment groups rather than studies, pooling ignores validity of the comparisons and is subject to a particular kind of bias, termed "Simpson's paradox." In contrast, meta-analysis and other stratified analyses are less susceptible to bias. Methods We use a hypothetical, but not atypical, application to demonstrate that the results of a meta-analysis can differ greatly from those obtained by pooling the same data. In our hypothetical model, a new drug is compared to 1 a placebo in 4 relatively small trials in patients at high risk for a certain adverse event and 2 an active reference drug in 2 larger trials of patients at low risk for this event. Results Using meta-analysis, the relative risk of experiencing the adverse event with the new drug was 1.78 (95% confidence interval [1.02; 3.12] compared to placebo and 2.20 [0.76; 6.32] compared to active control. By pooling the data, the results were, respectively, 1.00 [0.59; 1.70] and 5.20 [2.07; 13.08]. Conclusions Because these findings could mislead health authorities and doctors, regulatory agencies should require meta-analyses or stratified analyses of safety data in drug registration files.

  10. Prevalence of smoking in northwest Iran: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Mahmood Moosazadeh

    2014-01-01

    Full Text Available Background: Tobacco addiction is a major cause of preventable death worldwide. Thus, efforts to eliminate its use have the potential of producing significant health benefits. The purpose of this study was to conduct a meta-analysis to estimate the prevalence of cigarette smoking among people in the age range of 15 to 64. The specific objective of this meta-analysis was to provide valid data that policy makers can use to make evidence-based decisions. Methods: To determine the prevalence of smoking among the adult population in northwest Iran, we used reports published by the surveillance system used to assess the risk factors for non-communicable diseases in different provinces in northwest Iran for the years 2004 and 2006-2009. Several variables were extracted, including the years of study, gender, ages, and smoking prevalence. Based on the heterogeneity of the results, we used fixed or random effects models to estimate the overall prevalence of cigarette smoking. The analyses were performed using Stata 11 software. Results: A total of 28,436 subjects (14,248 males and 14,188 females in five age groups, i.e., 15-24, 25-34, 35-44, 45-54, and 55-64, were interviewed. Meta-analysis in men showed that, across the age groups, the lowest prevalence was 22.9%, the highest prevalence was 26.5%, and the average prevalence was 24.7%. Among women, the lowest prevalence was 0.3%, the highest prevalence was 0.8%, and the average prevalence was 0.5%. Conclusion: We found that approximately one-fourth of males in the age range of 15-64 in northwest Iran smoked cigarettes daily. Therefore, it is necessary to conduct effective interventions to reduce the prevalence of addiction to tobacco in this area.

  11. Robotic thyroidectomy versus endoscopic thyroidectomy: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Lin Shuang

    2012-11-01

    Full Text Available Abstract Background To conduct a meta-analysis to determine the relative merits of robotic thyroidectomy (RT and endoscopic thyroidectomy (ET. Methods A literature search was performed to identify comparative studies reporting peri-operative outcomes for RT and ET. Pooled odds ratios (ORs and weighted mean differences (WMDs with 95% confidence interval (95% CI were calculated using either a fixed-effects or a random-effects model. Results Six studies matched the selection criteria, which reported on 2048 subjects, of whom 978 underwent RT and 1070 underwent ET. Comparing the outcomes of RT with ET, this meta-analysis indicated that RT was associated with more complications (WMD = 1.51, 95% CI 1.18 to 1.94 and greater amount of drainage fluid (WMD = 17.10, 95% CI 5.69 to 28.51. Meanwhile, operating time (WMD = 1.50, 95% CI −39.59 to 42.58, conversion (WMD = 0.63, 95% CI 0.07 to 6.17, post-operative hospital stay (WMD = −0.05; 95% CI −0.18 to 0.08, and the number of lymph nodes harvested (WMD = 0.62, 95% CI −0.29 to 1.53 were similar for both procedures. Conclusion The results of this meta-analysis indicated that RT is associated with an increased risk of complications and a greater amount of drainage fluid. Therefore, RT does not appear to have any advantage over ET. Further studies are required to confirm these results.

  12. Meta-analysis of SNPs involved in variance heterogeneity using Levene's test for equal variances

    Science.gov (United States)

    Deng, Wei Q; Asma, Senay; Paré, Guillaume

    2014-01-01

    Meta-analysis is a commonly used approach to increase the sample size for genome-wide association searches when individual studies are otherwise underpowered. Here, we present a meta-analysis procedure to estimate the heterogeneity of the quantitative trait variance attributable to genetic variants using Levene's test without needing to exchange individual-level data. The meta-analysis of Levene's test offers the opportunity to combine the considerable sample size of a genome-wide meta-analysis to identify the genetic basis of phenotypic variability and to prioritize single-nucleotide polymorphisms (SNPs) for gene–gene and gene–environment interactions. The use of Levene's test has several advantages, including robustness to departure from the normality assumption, freedom from the influence of the main effects of SNPs, and no assumption of an additive genetic model. We conducted a meta-analysis of the log-transformed body mass index of 5892 individuals and identified a variant with a highly suggestive Levene's test P-value of 4.28E-06 near the NEGR1 locus known to be associated with extreme obesity. PMID:23921533

  13. Limitations in Using Multiple Imputation to Harmonize Individual Participant Data for Meta-Analysis.

    Science.gov (United States)

    Siddique, Juned; de Chavez, Peter J; Howe, George; Cruden, Gracelyn; Brown, C Hendricks

    2018-02-01

    Individual participant data (IPD) meta-analysis is a meta-analysis in which the individual-level data for each study are obtained and used for synthesis. A common challenge in IPD meta-analysis is when variables of interest are measured differently in different studies. The term harmonization has been coined to describe the procedure of placing variables on the same scale in order to permit pooling of data from a large number of studies. Using data from an IPD meta-analysis of 19 adolescent depression trials, we describe a multiple imputation approach for harmonizing 10 depression measures across the 19 trials by treating those depression measures that were not used in a study as missing data. We then apply diagnostics to address the fit of our imputation model. Even after reducing the scale of our application, we were still unable to produce accurate imputations of the missing values. We describe those features of the data that made it difficult to harmonize the depression measures and provide some guidelines for using multiple imputation for harmonization in IPD meta-analysis.

  14. Oxidative stress of crystalline lens in rat menopausal model

    Directory of Open Access Journals (Sweden)

    Semra Acer

    Full Text Available ABSTRACT Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1. From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2, 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3, and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4. Total oxidant status (TOS, total antioxidant capacity (TAC, and oxidative stress index (OSI measurements of the crystalline lenses were analyzed. Results: The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05. The mean TOS values were similar between the groups (p >0.05, whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001. Conclusions: Our results indicate that menopause may not promote cataract formation.

  15. Oxidative stress of crystalline lens in rat menopausal model.

    Science.gov (United States)

    Acer, Semra; Pekel, Gökhan; Küçükatay, Vural; Karabulut, Aysun; Yağcı, Ramazan; Çetin, Ebru Nevin; Akyer, Şahika Pınar; Şahin, Barbaros

    2016-01-01

    To evaluate lenticular oxidative stress in rat menopausal models. Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3), and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4). Total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI) measurements of the crystalline lenses were analyzed. The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05). The mean TOS values were similar between the groups (p >0.05), whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001). Our results indicate that menopause may not promote cataract formation.

  16. Association between Lutein and Zeaxanthin Status and the Risk of Cataract: A Meta-Analysis

    Science.gov (United States)

    Liu, Xiao-Hong; Yu, Rong-Bin; Liu, Rong; Hao, Zhen-Xuan; Han, Cheng-Cheng; Zhu, Zhong-Hai; Ma, Le

    2014-01-01

    The purpose of this meta-analysis was to evaluate the relationship between blood lutein and zeaxanthin concentration and the risk of age-related cataract (ARC). MEDLINE, EMBASE, ISI and Cochrane Library were searched to identify relevant studies up to April 2013. Meta-analysis was conducted to obtain pooled relative risks (RRs) for the highest-versus-lowest categories of blood lutein and zeaxanthin concentrations. One cohort study and seven cross-sectional studies were included in the meta-analysis. There were significant inverse associations between nuclear cataract and blood lutein and zeaxanthin concentrations, with the pooled RRs ranging from 0.63 (95% confidence interval (CI): 0.49, 0.77) for zeaxanthin to 0.73 (95% CI: 0.59, 0.87) for lutein. A stronger association between nuclear cataract and blood zeaxanthin might be noted for the studies conducted in the European Nations. Blood lutein and zeaxanthin were also noted to lead towards a decrease in the risk of cortical cataract and subcapsular cataract; however, these pooled RRs were not statistically significant, with the exception of a marginal association between lutein and subcapsular cataract. Our results suggest that high blood lutein and zeaxanthin are significantly associated with a decrease in the risk of nuclear cataract. However, no significant associations were found for ARC in other regions of the lens. PMID:24451312

  17. A Thin Lens Model for Charged-Particle RF Accelerating Gaps

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Christopher K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-07-01

    Presented is a thin-lens model for an RF accelerating gap that considers general axial fields without energy dependence or other a priori assumptions. Both the cosine and sine transit time factors (i.e., Fourier transforms) are required plus two additional functions; the Hilbert transforms the transit-time factors. The combination yields a complex-valued Hamiltonian rotating in the complex plane with synchronous phase. Using Hamiltonians the phase and energy gains are computed independently in the pre-gap and post-gap regions then aligned using the asymptotic values of wave number. Derivations of these results are outlined, examples are shown, and simulations with the model are presented.

  18. The selection, optimization, and compensation model in the work context : A systematic review and meta-analysis of two decades of research

    NARCIS (Netherlands)

    Moghimi, Darya; Zacher, Hannes; Scheibe, Susanne; Van Yperen, Nico W.

    Over the past two decades, the selection, optimization, and compensation (SOC) model has been applied in the work context to investigate antecedents and outcomes of employees’ use of action regulation strategies. We systematically review, meta-analyze, and critically discuss the literature on SOC

  19. Taming Human Genetic Variability: Transcriptomic Meta-Analysis Guides the Experimental Design and Interpretation of iPSC-Based Disease Modeling

    Directory of Open Access Journals (Sweden)

    Pierre-Luc Germain

    2017-06-01

    Full Text Available Both the promises and pitfalls of the cell reprogramming research platform rest on human genetic variation, making the measurement of its impact one of the most urgent issues in the field. Harnessing large transcriptomics datasets of induced pluripotent stem cells (iPSC, we investigate the implications of this variability for iPSC-based disease modeling. In particular, we show that the widespread use of more than one clone per individual in combination with current analytical practices is detrimental to the robustness of the findings. We then proceed to identify methods to address this challenge and leverage multiple clones per individual. Finally, we evaluate the specificity and sensitivity of different sample sizes and experimental designs, presenting computational tools for power analysis. These findings and tools reframe the nature of replicates used in disease modeling and provide important resources for the design, analysis, and interpretation of iPSC-based studies.

  20. Online Open Neuroimaging Mass Meta-Analysis with a Wiki

    DEFF Research Database (Denmark)

    Nielsen, Finn Arup; Kempton, Matthew J.; Williams, Steven C. R.

    2015-01-01

    We describe a system for meta-analysis where a wiki stores numerical data in a simple comma-separated values format and a web service performs the numerical statistical computation. We initially apply the system on multiple meta-analyses of structural neuroimaging data results. The described system...... allows for mass meta-analysis, e.g., meta-analysis across multiple brain regions and multiple mental disorders providing an overview of important relationships and their uncertainties in a collaborative environment....

  1. The uterine leiomyoma and placenta previa: a meta-analysis.

    Science.gov (United States)

    Jenabi, Ensiyeh; Fereidooni, Bita

    2017-11-21

    Some epidemiological studies have reported that uterine leiomyoma may increase the risk of placenta previa. To date, the meta-analysis has not been carried out for assessing the relationship between uterine leiomyoma and placenta previa. This meta-analysis was carried out to estimate the association between uterine leiomyoma and the risk of placenta previa. A systematic search was conducted out in major databases PubMed, Web of Science, and Scopus from the earliest possible year to June 2017. The heterogeneity across studies was explored by Q-test and I 2 statistic. The publication bias was assessed by Begg's and Egger's tests. The results were showed using odds ratio (OR) estimate with its 95% confidence intervals (CI) using a random-effects model. The literature search included 1218 articles until to June 2017 with 255,886 women. Based on OR estimates obtained from case-control and cohort studies, there was significant association between uterine leiomyoma and placenta previa in studies adjusted (2.21; 95%CI: 1.48, 2.94). We showed based on reports in observational studies that uterine leiomyoma is a risk factor for placenta previa in studies adjusted.

  2. Meta-analysis: pharmacological treatment of pathological gambling.

    Science.gov (United States)

    Bartley, Christine A; Bloch, Michael H

    2013-08-01

    This meta-analysis investigates the efficacy of pharmacological treatments for pathological gambling (PG). We searched for randomized, placebo-controlled trials examining pharmacotherapy of pathological gamblers. A fixed-effects model was used to calculate the standardized mean difference (SMD) of the benefit of medication (stratified by class) compared to placebo. Secondary analyses examined the effects of publication bias, year of publication and adherence to intention-to-treat (ITT) principles on reported efficacy of interventions. Meta-analysis included 14 trials involving 1024 participants. Opiate antagonists demonstrated a small but significant benefit compared to placebo (SMD = 0.22 ± 0.10 (95% CI: 0.03-0.41), z = 2.3, p = 0.02). The reported efficacy of opiate antagonists was significantly associated with non-adherence to ITT principles in trials and earlier year of publication. Other medications had non-significant effect sizes compared to placebo but similar in magnitude to opiate antagonists. Current trial data provides limited support for the use of any pharmacological agent in the treatment of pathological gambling.

  3. Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Olivier Le Polain de Waroux

    Full Text Available INTRODUCTION: Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children. METHODS: We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT serotypes in older age groups as a function of that in <5 y olds. RESULTS: Twenty-nine studies compromising of 20,391 individuals were included in the analysis. In all studies nasopharyngeal carriage decreased with increasing age. We found a strong positive linear association between the carriage prevalence in pre-school childen (<5 y and both that in school aged children (5-17 y olds and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5-17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5-17 y olds and adults as a function of that in children <5 years of age. CONCLUSION: Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.

  4. Age-dependent prevalence of nasopharyngeal carriage of streptococcus pneumoniae before conjugate vaccine introduction: a prediction model based on a meta-analysis.

    Science.gov (United States)

    Le Polain de Waroux, Olivier; Flasche, Stefan; Prieto-Merino, David; Edmunds, W John

    2014-01-01

    Data on the prevalence of nasopharyngeal carriage of S.pneumoniae in all age groups are important to help predict the impact of introducing pneumococcal conjugate vaccines (PCV) into routine infant immunization, given the important indirect effect of the vaccine. Yet most carriage studies are limited to children under five years of age. We here explore the association between carriage prevalence and serotype distribution in children aged ≥5 years and in adults compared to children. We conducted a systematic review of studies providing carriage estimates across age groups in healthy populations not previously exposed to PCV, using MEDLINE and Embase. We used Bayesian linear meta-regression models to predict the overall carriage prevalence as well as the prevalence and distribution of vaccine and nonvaccine type (VT and NVT) serotypes in older age groups as a function of that in linear association between the carriage prevalence in pre-school childen (<5 y) and both that in school aged children (5-17 y olds) and in adults. The proportion of VT serotypes isolated from carriers was consistently lower in older age groups and on average about 73% that of children <5 y among 5-17 y olds and adults respectively. We provide a prediction model to infer the carriage prevalence and serotype distribution in 5-17 y olds and adults as a function of that in children <5 years of age. Such predictions are helpful for assessing the potential population-wide effects of vaccination programmes, e.g. via transmission models, and thus assist in the design of future pneumococcal conjugate vaccination strategies.

  5. Comparative pharmacophore modeling of organic anion transporting polypeptides: a meta-analysis of rat Oatp1a1 and human OATP1B1.

    Science.gov (United States)

    Chang, Cheng; Pang, K Sandy; Swaan, Peter W; Ekins, Sean

    2005-08-01

    The organic anion transporting polypeptides OATPs are key membrane transporters for which crystal structures are not currently available. They transport a diverse array of xenobiotics and are expressed at the interface of hepatocytes, renal tubular cells, enterocytes, and the choroid plexus. To aid the understanding of the key molecular features for substrate-transporter interactions, pharmacophore models were produced for the two OATPs that have been most extensively studied, namely rat Oatp1a1 and human OATP1B1. Literature data from Chinese hamster ovary, HeLa, human embryonic kidney 293 cells, and Xenopus laevis oocytes were used to construct pharmacophores for each individual transporter which were later merged to show similarities across cell lines for the same transporter. Additionally, meta-pharmacophores were generated from the combined datasets of each cell system used with the same transporter. The pharmacophores for each transporter consisted of hydrogen bond acceptor and hydrophobic features. There was good agreement between the merged and meta-pharmacophores containing two hydrogen bond acceptors and two or three hydrophobic features for Oatp1a1 and OATP1B1. External test sets were used to validate the individual pharmacophores. The meta-pharmacophores were also used to make predictions for molecules not included in the models and provided new molecular insight into the key features for these OATP transporters. This approach can be extended to other transporters for which limited data are available.

  6. Roles of caloric restriction, ketogenic diet and intermittent fasting during initiation, progression and metastasis of cancer in animal models: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Mengmeng Lv

    Full Text Available The role of dietary restriction regimens such as caloric restriction, ketogenic diet and intermittent fasting in development of cancers has been detected via abundant preclinical experiments. However, the conclusions are controversial. We aim to review the relevant animal studies systematically and provide assistance for further clinical studies.Literatures on associations between dietary restriction and cancer published in PubMed in recent twenty years were comprehensively searched. Animal model, tumor type, feeding regimen, study length, sample size, major outcome, conclusion, quality assessment score and the interferential step of cancer were extracted from each eligible study. We analyzed the tumor incidence rates from 21 studies about caloric restriction.Fifty-nine studies were involved in our system review. The involved studies explored roles of dietary restriction during initiation, progression and metastasis of cancer. About 90.9% of the relevant studies showed that caloric restriction plays an anti-cancer role, with the pooled OR (95%CI of 0.20 (0.12, 0.34 relative to controls. Ketogenic diet was also positively associated with cancer, which was indicated by eight of the nine studies. However, 37.5% of the related studies obtained a negative conclusion that intermittent fasting was not significantly preventive against cancer.Caloric restriction and ketogenic diet are effective against cancer in animal experiments while the role of intermittent fasting is doubtful and still needs exploration. More clinical experiments are needed and more suitable patterns for humans should be investigated.

  7. Roles of caloric restriction, ketogenic diet and intermittent fasting during initiation, progression and metastasis of cancer in animal models: a systematic review and meta-analysis.

    Science.gov (United States)

    Lv, Mengmeng; Zhu, Xingya; Wang, Hao; Wang, Feng; Guan, Wenxian

    2014-01-01

    The role of dietary restriction regimens such as caloric restriction, ketogenic diet and intermittent fasting in development of cancers has been detected via abundant preclinical experiments. However, the conclusions are controversial. We aim to review the relevant animal studies systematically and provide assistance for further clinical studies. Literatures on associations between dietary restriction and cancer published in PubMed in recent twenty years were comprehensively searched. Animal model, tumor type, feeding regimen, study length, sample size, major outcome, conclusion, quality assessment score and the interferential step of cancer were extracted from each eligible study. We analyzed the tumor incidence rates from 21 studies about caloric restriction. Fifty-nine studies were involved in our system review. The involved studies explored roles of dietary restriction during initiation, progression and metastasis of cancer. About 90.9% of the relevant studies showed that caloric restriction plays an anti-cancer role, with the pooled OR (95%CI) of 0.20 (0.12, 0.34) relative to controls. Ketogenic diet was also positively associated with cancer, which was indicated by eight of the nine studies. However, 37.5% of the related studies obtained a negative conclusion that intermittent fasting was not significantly preventive against cancer. Caloric restriction and ketogenic diet are effective against cancer in animal experiments while the role of intermittent fasting is doubtful and still needs exploration. More clinical experiments are needed and more suitable patterns for humans should be investigated.

  8. Meta-analysis of field-saturated hydraulic conductivity recovery following wildland fire: Applications for hydrologic model parameterization and resilience assessment

    Science.gov (United States)

    Ebel, Brian A.; Martin, Deborah

    2017-01-01

    Hydrologic recovery after wildfire is critical for restoring the ecosystem services of protecting of human lives and infrastructure from hazards and delivering water supply of sufficient quality and quantity. Recovery of soil-hydraulic properties, such as field-saturated hydraulic conductivity (Kfs), is a key factor for assessing the duration of watershed-scale flash flood and debris flow risks after wildfire. Despite the crucial role of Kfs in parameterizing numerical hydrologic models to predict the magnitude of postwildfire run-off and erosion, existing quantitative relations to predict Kfsrecovery with time since wildfire are lacking. Here, we conduct meta-analyses of 5 datasets from the literature that measure or estimate Kfs with time since wildfire for longer than 3-year duration. The meta-analyses focus on fitting 2 quantitative relations (linear and non-linear logistic) to explain trends in Kfs temporal recovery. The 2 relations adequately described temporal recovery except for 1 site where macropore flow dominated infiltration and Kfs recovery. This work also suggests that Kfs can have low hydrologic resistance (large postfire changes), and moderate to high hydrologic stability (recovery time relative to disturbance recurrence interval) and resilience (recovery of hydrologic function and provision of ecosystem services). Future Kfs relations could more explicitly incorporate processes such as soil-water repellency, ground cover and soil structure regeneration, macropore recovery, and vegetation regrowth.

  9. Transformations of summary statistics as input in meta-analysis for linear dose–response models on a logarithmic scale: a methodology developed within EURRECA

    Directory of Open Access Journals (Sweden)

    Souverein Olga W

    2012-04-01

    Full Text Available Abstract Background To derive micronutrient recommendations in a scientifically sound way, it is important to obtain and analyse all published information on the association between micronutrient intake and biochemical proxies for micronutrient status using a systematic approach. Therefore, it is important to incorporate information from randomized controlled trials as well as observational studies as both of these provide information on the association. However, original research papers present their data in various ways. Methods This paper presents a methodology to obtain an estimate of the dose–response curve, assuming a bivariate normal linear model on the logarithmic scale, incorporating a range of transformations of the original reported data. Results The simulation study, conducted to validate the methodology, shows that there is no bias in the transformations. Furthermore, it is shown that when the original studies report the mean and standard deviation or the geometric mean and confidence interval the results are less variable compared to when the median with IQR or range is reported in the original study. Conclusions The presented methodology with transformations for various reported data provides a valid way to estimate the dose–response curve for micronutrient intake and status using both randomized controlled trials and observational studies.

  10. REFRACTIVE NEUTRON LENS

    OpenAIRE

    Petrov, P. V.; Kolchevsky, N. N.

    2013-01-01

    Compound concave refractive lenses are used for focusing neutron beam. Investigations of spectral and focusing properties of a refractive neutron lens are presented. Resolution of the imaging system on the base of refractive neutron lenses depends on material properties and parameters of neutron source. Model of refractive neutron lens are proposed. Results of calculation diffraction resolution and focal depth of refractive neutron lens are discussed.

  11. The effectiveness of theory- and model-based lifestyle interventions on HbA1c among patients with type 2 diabetes: a systematic review and meta-analysis.

    Science.gov (United States)

    Doshmangir, P; Jahangiry, L; Farhangi, M A; Doshmangir, L; Faraji, L

    2018-02-01

    The prevalence of type 2 diabetes is rising rapidly around the world. A number of systematic reviews have provided evidence for the effectiveness of lifestyle interventions on diabetic patients. The effectiveness of theory- and model-based education-lifestyle interventions for diabetic patients are unclear. The systematic review and meta-analysis aimed to evaluate and quantify the impact of theory-based lifestyle interventions on type 2 diabetes. A literature search of authentic electronic resources including PubMed, Scopus, and Cochrane collaboration was performed to identify published papers between January 2002 and July 2016. The PICOs (participants, intervention, comparison, and outcomes) elements were used for the selection of studies to meet the inclusion and exclusion criteria. Mean differences and standard deviations of hemoglobin A1c (HbA1c [mmol/mol]) level in baseline and follow-up measures of studies in intervention and control groups were considered for data synthesis. A random-effects model was used for estimating pooled effect sizes. To investigate the source of heterogeneity, predefined subgroup analyses were performed using trial duration, baseline HbA1c (mmol/mol) level, and the age of participants. Meta-regression was performed to examine the contribution of trial duration, baseline HbA1c (mmol/mol) level, the age of participants, and mean differences of HbA1c (mmol/mol) level. The significant level was considered P model showed significant improvements in HbA1c (mmol/mol) -5.35% (95% confidence interval = -6.3, -4.40; P theory- and model-based lifestyle interventions have positive effects on HbA1c (mmol/mol) indices in patients with type 2 diabetes. Health education theories have been applied as a useful tool for lifestyle change among people with type 2 diabetes. Copyright © 2017 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

  12. Digital Games, Design, and Learning: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Clark, Douglas B.; Tanner-Smith, Emily E.; Killingsworth, Stephen S.

    2016-01-01

    In this meta-analysis, we systematically reviewed research on digital games and learning for K-16 students. We synthesized comparisons of game versus nongame conditions (i.e., media comparisons) and comparisons of augmented games versus standard game designs (i.e., value-added comparisons). We used random-effects meta-regression models with robust…

  13. Improving Treatment Plan Implementation in Schools: A Meta-Analysis of Single Subject Design Studies

    Science.gov (United States)

    Noell, George H.; Gansle, Kristin A.; Mevers, Joanna Lomas; Knox, R. Maria; Mintz, Joslyn Cynkus; Dahir, Amanda

    2014-01-01

    Twenty-nine peer-reviewed journal articles that analyzed intervention implementation in schools using single-case experimental designs were meta-analyzed. These studies reported 171 separate data paths and provided 3,991 data points. The meta-analysis was accomplished by fitting data extracted from graphs in mixed linear growth models. This…

  14. A Meta-Analysis of Adult-Rated Child Personality and Academic Performance in Primary Education

    Science.gov (United States)

    Poropat, Arthur E.

    2014-01-01

    Background: Personality is reliably associated with academic performance, but personality measurement in primary education can be problematic. Young children find it difficult to accurately self-rate personality, and dominant models of adult personality may be inappropriate for children. Aims: This meta-analysis was conducted to determine the…

  15. Teaching meta-analysis using MetaLight

    Directory of Open Access Journals (Sweden)

    Thomas James

    2012-10-01

    Full Text Available Abstract Background Meta-analysis is a statistical method for combining the results of primary studies. It is often used in systematic reviews and is increasingly a method and topic that appears in student dissertations. MetaLight is a freely available software application that runs simple meta-analyses and contains specific functionality to facilitate the teaching and learning of meta-analysis. While there are many courses and resources for meta-analysis available and numerous software applications to run meta-analyses, there are few pieces of software which are aimed specifically at helping those teaching and learning meta-analysis. Valuable teaching time can be spent learning the mechanics of a new software application, rather than on the principles and practices of meta-analysis. Findings We discuss ways in which the MetaLight tool can be used to present some of the main issues involved in undertaking and interpreting a meta-analysis. Conclusions While there are many software tools available for conducting meta-analysis, in the context of a teaching programme such software can require expenditure both in terms of money and in terms of the time it takes to learn how to use it. MetaLight was developed specifically as a tool to facilitate the teaching and learning of meta-analysis and we have presented here some of the ways it might be used in a training situation.

  16. Meta-analysis in epidemiology | Yach | South African Medical Journal

    African Journals Online (AJOL)

    Meta-analysis is the structured and systematic qualitative and quantitative integration of the results of several independent studies (Le. the epidemiology of results). As in any epidemiological study, a meta-analysis needs to start with clearly stated aims and objectives. Attention needs to be paid to selection bias in selecting ...

  17. Systematic reviews with meta-analysis: Why, when, and how?

    NARCIS (Netherlands)

    Crocetti, E.

    2016-01-01

    Systematic reviews with meta-analysis represent the gold standard for conducting reliable and transparent reviews of the literature. The purpose of this article is threefold: (a) to address why and when it is worthwhile to conduct a systematic review with meta-analysis, covering advantages of this

  18. Statistical learning in specific language impairment : A meta-analysis

    NARCIS (Netherlands)

    Lammertink, Imme; Boersma, Paul; Wijnen, Frank; Rispens, Judith

    2017-01-01

    Purpose: The current meta-analysis provides a quantitative overview of published and unpublished studies on statistical learning in the auditory verbal domain in people with and without specific language impairment (SLI). The database used for the meta-analysis is accessible online and open to

  19. Meta-analysis in a nutshell: Techniques and general findings

    DEFF Research Database (Denmark)

    Paldam, Martin

    2015-01-01

    The purpose of this article is to introduce the technique and main findings of meta-analysis to the reader, who is unfamiliar with the field and has the usual objections. A meta-analysis is a quantitative survey of a literature reporting estimates of the same parameter. The funnel showing...

  20. Physical Activity and Risk of Lymphoma: A Meta-Analysis

    NARCIS (Netherlands)

    Vermaete, N.V.H.; Wolter, P.; Verhoef, G.E.G.; Kollen, B.J.; Kwakkel, G.; Schepers, L.; Gosselink, R.

    2013-01-01

    Background: Physical activity has a protective effect on some types of cancer. The aim of the present meta-analysis was to explore the literature on the association between physical activity and risk of lymphoma. Methods: A meta-analysis was conducted for cohort and case-control studies examining

  1. Physical Activity and Risk of Lymphoma : A Meta-Analysis

    NARCIS (Netherlands)

    Vermaete, Nele V. H.; Wolter, Pascal; Verhoef, Gregor E. G.; Kollen, Boudewijn J.; Kwakkel, Gert; Schepers, Leen; Gosselink, Rik

    Background: Physical activity has a protective effect on some types of cancer. The aim of the present meta-analysis was to explore the literature on the association between physical activity and risk of lymphoma. Methods: A meta-analysis was conducted for cohort and case-control studies examining

  2. Estimating individual rates of discount: A meta-analysis

    NARCIS (Netherlands)

    Percoco, M.; Nijkamp, P.

    2009-01-01

    In this article, we present the results from a meta-analysis conducted over 44 experimental and field studies, which report individual discount rate estimates. We find in our research that the experimental design of a study has a decisive impact on these estimates, and conclude that meta-analysis,

  3. The health effects of education: A meta-analysis

    NARCIS (Netherlands)

    Furnée, C.A.; Groot, W.; Maassen van den Brink, H.

    2008-01-01

    Background: There is an abundance of empirical evidence, mainly from the epidemiological and social science literature, on the relation between education and health. Until now a meta-analysis of the relation between education and health was not available. This article presents a meta-analysis of

  4. Comparing Active Pediatric Obesity Treatments Using Meta-Analysis

    Science.gov (United States)

    Gilles, Allyson; Cassano, Michael; Shepherd, Elizabeth J.; Higgins, Diana; Hecker, Jeffrey E.; Nangle, Douglas W.

    2008-01-01

    The current meta-analysis reviews research on the treatment of pediatric obesity focusing on studies that have been published since 1994. Eleven studies (22 comparisons, 115 effect sizes, N = 447) were included in the present meta-analysis. Results indicated that comprehensive behavioral interventions may be improved in at least two ways:…

  5. META-ANALYSIS: THE WAY FORWARD IN MEDICAL DISCOVERY

    African Journals Online (AJOL)

    data, and (6) report the results. Define the Research Question. A meta-analysis begins with a question. Common questions addressed in meta-analyses are whether one. META-ANALYSIS: THE WAY FORWARD IN MEDICAL DISCOVERY. Akinyemi J.O. MSc (Medical Statistics), B Tech (Comp. Sc.) Correspondence:.

  6. [Eye lens radiation exposure during ureteroscopy with and without a face protection shield: Investigations on a phantom model].

    Science.gov (United States)

    Zöller, G; Figel, M; Denk, J; Schulz, K; Sabo, A

    2016-03-01

    Eye lens radiation exposure during radiologically-guided endoscopic procedures may result in radiation-induced cataracts; therefore, we investigated the ocular radiation exposure during ureteroscopy on a phantom model. Using an Alderson phantom model and eye lens dosimeters, we measured the ocular radiation exposure depending on the number of X-ray images and on the duration of fluoroscopic imaging. The measurements were done with and without using a face protection shield. We could demonstrate that a significant ocular radiation exposure can occur, depending on the number of X-ray images and on the duration time of fluoroscopy. Eye lens doses up to 0.025 mSv were recorded even using modern digital X-ray systems. Using face protection shields this ocular radiation exposure can be reduced to a minimum. The International Commission on Radiological Protection (ICRP) recommendations of a mean eye lens dosage of 20 mSv/year may be exceeded during repeated ureteroscopy by a high volume surgeon. Using a face protection shield, the eye lens dose during ureteroscopy could be reduced to a minimum in a phantom model. Further investigations will show whether these results can be transferred to real life ureteroscopic procedures.

  7. Sensitivity analysis for publication bias in meta-analysis of diagnostic studies for a continuous biomarker.

    Science.gov (United States)

    Hattori, Satoshi; Zhou, Xiao-Hua

    2018-02-10

    Publication bias is one of the most important issues in meta-analysis. For standard meta-analyses to examine intervention effects, the funnel plot and the trim-and-fill method are simple and widely used techniques for assessing and adjusting for the influence of publication bias, respectively. However, their use may be subjective and can then produce misleading insights. To make a more objective inference for publication bias, various sensitivity analysis methods have been proposed, including the Copas selection model. For meta-analysis of diagnostic studies evaluating a continuous biomarker, the summary receiver operating characteristic (sROC) curve is a very useful method in the presence of heterogeneous cutoff values. To our best knowledge, no methods are available for evaluation of influence of publication bias on estimation of the sROC curve. In this paper, we introduce a Copas-type selection model for meta-analysis of diagnostic studies and propose a sensitivity analysis method for publication bias. Our method enables us to assess the influence of publication bias on the estimation of the sROC curve and then judge whether the result of the meta-analysis is sufficiently confident or should be interpreted with much caution. We illustrate our proposed method with real data. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Personality traits and personal values: a meta-analysis.

    Science.gov (United States)

    Parks-Leduc, Laura; Feldman, Gilad; Bardi, Anat

    2015-02-01

    Personality traits and personal values are important psychological characteristics, serving as important predictors of many outcomes. Yet, they are frequently studied separately, leaving the field with a limited understanding of their relationships. We review existing perspectives regarding the nature of the relationships between traits and values and provide a conceptual underpinning for understanding the strength of these relationships. Using 60 studies, we present a meta-analysis of the relationships between the Five-Factor Model (FFM) of personality traits and the Schwartz values, and demonstrate consistent and theoretically meaningful relationships. However, these relationships were not generally large, demonstrating that traits and values are distinct constructs. We find support for our premise that more cognitively based traits are more strongly related to values and more emotionally based traits are less strongly related to values. Findings also suggest that controlling for personal scale-use tendencies in values is advisable. © 2014 by the Society for Personality and Social Psychology, Inc.

  9. Personality and transformational and transactional leadership: a meta-analysis.

    Science.gov (United States)

    Bono, Joyce E; Judge, Timothy A

    2004-10-01

    This study was a meta-analysis of the relationship between personality and ratings of transformational and transactional leadership behaviors. Using the 5-factor model of personality as an organizing framework, the authors accumulated 384 correlations from 26 independent studies. Personality traits were related to 3 dimensions of transformational leadership--idealized influence-inspirational motivation (charisma), intellectual stimulation, and individualized consideration--and 3 dimensions of transactional leadership--contingent reward, management by exception-active, and passive leadership. Extraversion was the strongest and most consistent correlate of transformational leadership. Although results provided some support for the dispositional basis of transformational leadership--especially with respect to the charisma dimension--generally, weak associations suggested the importance of future research to focus on both narrower personality traits and nondispositional determinants of transformational and transactional leadership. (c) 2004 APA, all rights reserved

  10. Religion and Completed Suicide: a Meta-Analysis.

    Science.gov (United States)

    Wu, Andrew; Wang, Jing-Yu; Jia, Cun-Xian

    2015-01-01

    Suicide is a major public health concern and a leading cause of death around the world. How religion influences the risk of completed suicide in different settings across the world requires clarification in order to best inform suicide prevention strategies. A meta-analysis using search results from Pubmed and Web of Science databases was conducted following PRISMA protocol and using the keywords "religion" or "religious" or "religiosity" or "spiritual" or "spirituality" plus "suicide" or "suicidality" or "suicide attempt". Random and fixed effects models were used to generate pooled ORs and I2 values. Sub-analyses were conducted among the following categories: young age (Religion plays a protective role against suicide in a majority of settings where suicide research is conducted. However, this effect varies based on the cultural and religious context. Therefore, public health professionals need to strongly consider the current social and religious atmosphere of a given population when designing suicide prevention strategies.

  11. Sex differences in romantic attachment: a meta-analysis.

    Science.gov (United States)

    Del Giudice, Marco

    2011-02-01

    This article presents the first meta-analysis of sex differences in the avoidance and anxiety dimensions of adult romantic attachment, based on 113 samples (N = 66,132) from 100 studies employing two-dimensional romantic attachment questionnaires (Experiences in Close Relationships, Experiences in Close Relationships-Revised, and Adult Attachment Questionnaire). Overall, males showed higher avoidance and lower anxiety than females, with substantial between-study heterogeneity. Sex differences were much larger in community samples (bivariate D = .28) than in college samples (D = .12); web-based studies showed the smallest sex differences (D = .07) in the opposite direction. Sex differences also varied across geographic regions (overall Ds = .10 to .34). Sex differences in anxiety peaked in young adulthood, whereas those in avoidance increased through the life course. The relevance of these findings for evolutionary models of romantic attachment is discussed, and possible factors leading to underestimation of sex differences are reviewed.

  12. Proposed Sources of Coaching Efficacy: A Meta-Analysis.

    Science.gov (United States)

    Myers, Nicholas D; Park, Sung Eun; Ahn, Soyeon; Lee, Seungmin; Sullivan, Philip J; Feltz, Deborah L

    2017-08-01

    Coaching efficacy refers to the extent to which a coach believes that he or she has the capacity to affect the learning and performance of his or her athletes. The purpose of the current study was to empirically synthesize findings across the extant literature to estimate relationships between the proposed sources of coaching efficacy and each of the dimensions of coaching efficacy. A literature search yielded 20 studies and 278 effect size estimates that met the inclusion criteria. The overall relationship between the proposed sources of coaching efficacy and each dimension of coaching efficacy was positive and ranged from small to medium in size. Coach gender and level coached moderated the overall relationship between the proposed sources of coaching efficacy and each of the dimensions of coaching efficacy. Results from this meta-analysis provided some evidence for both the utility of, and possible revisions to, the conceptual model of coaching efficacy.

  13. A Meta-Analysis on Prehypertension and Chronic Kidney Disease.

    Directory of Open Access Journals (Sweden)

    Yang Li

    Full Text Available Recent studies have demonstrated that there is an association between prehypertension and an increased risk of end-stage renal disease. However, there is conflicting evidence regarding the relationship between prehypertension and chronic kidney disease (CKD. This meta-analysis aimed to demonstrate the association between prehypertension and the incidence of CKD and identify the impacts of gender and ethnic differences.MEDLINE, EMBASE, Cochrane Library (from inception through March 2016 and article reference lists were searched for relevant studies regarding blood pressure and CKD. Blood pressure (BP measurements were classified as follows: optimal BP (less than 120/80 mmHg, prehypertension (120-139/80-89 mmHg and hypertension (over 140/90 mmHg. CKD was defined by estimated glomerular filtration rate (eGFR<60 ml/min/1.73 m2 or proteinuria. Two investigators independently extracted the data and assessed the quality of studies enrolled in this meta-analysis using the Newcastle-Ottawa Scale (NOS. We performed the meta-analysis using Stata/SE 12.0 (StataCorp LP. The random-effect models were used in the heterogeneous analyses.After retrieving data from 4,537 potentially relevant articles, we identified 7 cohort studies including 261,264 subjects, according to the predefined selection criteria. Five studies were conducted in Mongolians from East Asia, and the other two studies were performed in Indo-Europeans from Austria and Iran. The participants ranged in age from 20 to 89 years, and the proportion of females ranged from 27.2% to 63.8%. The follow-up period ranged from 2 to 11 years. Compared with the optimal BP values, prehypertension showed an increased risk of CKD (pooled RR = 1.28; 95% CI = 1.13-1.44; P = 0.000; I2 = 77.9%. In the sex-stratified analysis, we found a similar trend in women (pooled RR = 1.29; 95% CI = 1.01-1.63; P = 0.039; I2 = 76.1% but not in men. This effect was observed only in Mongolians from East Asia (pooled RR = 1.37; 95

  14. Critical Thinking Development in Pharmacy Education: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Michael J Peeters

    2016-03-01

    Full Text Available Objective: The investigators aimed to summarize prior studies of critical thinking development among pharmacy students, using the California Critical Thinking Skills Test (CCTST, Health Sciences Reasoning Test (HSRT, and Defining Issues Test (DIT. Methods: Independently, two investigators (KLZ, MJP systematically searched available literature using PubMed, Google Scholar, ERIC, PsychInfo, as well as pharmacy education conference abstracts in American Journal of Pharmaceutical Education. Their search terms were ‘pharmacy’, and [‘critical thinking’, ‘HSRT’, ‘CCTST’, and ‘DIT’]. Studies included were those that investigated pharmacy students, used one of the tests (CCTST, HSRT, DIT, and used a longitudinal design with test administration at two or more time-points for the same subjects (i.e., development. On review, the CCTST and HSRT seem more foundational to analytical/critical thinking, while the DIT appears to measure moral/complex thinking. Summarizing used meta-analysis with Cohen’s d and random-effects modelling. Results: Five studies involved thinking development with 10 separate cohorts for meta-analysis (8 cohorts for CCTST, 2 for DIT, and 0 for HSRT. At 5 institutions, 407 and 1148 students were included (CCTST and DIT, respectively. For the CCTST, the overall effect was 0.33 (0.19-0.47 95%CI with some heterogeneity among study cohorts (I2=52%. For the DIT, the overall effect was -0.23 (-0.83-0.37 95%CI with considerable heterogeneity between study cohorts (I2=95%. For the CCTST and DIT, some studies showed effect-sizes greater than 0.5. Meta-analysis of the HSRT could not be conducted (i.e., 0 studies found. Implications: While measuring different aspects of “critical thinking”, the CCTST and DIT showed responsiveness to change and appear to be promising measures of cognitive development. These tests should be used in further well-designed research studies that explore strategies for improving cognitive

  15. Cognitive Expertise: An ALE Meta-Analysis.

    Science.gov (United States)

    Neumann, Nicola; Lotze, Martin; Eickhoff, Simon B

    2016-01-01

    Expert performance constitutes the endpoint of skill acquisition and is accompanied by widespread neuroplastic changes. To reveal common mechanisms of reorganization associated with long-term expertise in a cognitive domain (mental calculation, chess, language, memory, music without motor involvement), we used activation likelihood estimation meta-analysis and compared brain activation of experts to nonexperts. Twenty-six studies matched inclusion criteria, most of which reported an increase and not a decrease of activation foci in experts. Increased activation occurred in the left rolandic operculum (OP 4) and left primary auditory cortex and in bilateral premotor cortex in studies that used auditory stimulation. In studies with visual stimulation, experts showed enhanced activation in the right inferior parietal cortex (area PGp) and the right lingual gyrus. Experts' brain activation patterns seem to be characterized by enhanced or additional activity in domain-specific primary, association, and motor structures, confirming that learning is localized and very specialized. © 2015 Wiley Periodicals, Inc.

  16. Sequential Stereotype Priming: A Meta-Analysis.

    Science.gov (United States)

    Kidder, Ciara K; White, Katherine R; Hinojos, Michelle R; Sandoval, Mayra; Crites, Stephen L

    2017-08-01

    Psychological interest in stereotype measurement has spanned nearly a century, with researchers adopting implicit measures in the 1980s to complement explicit measures. One of the most frequently used implicit measures of stereotypes is the sequential priming paradigm. The current meta-analysis examines stereotype priming, focusing specifically on this paradigm. To contribute to ongoing discussions regarding methodological rigor in social psychology, one primary goal was to identify methodological moderators of the stereotype priming effect-whether priming is due to a relation between the prime and target stimuli, the prime and target response, participant task, stereotype dimension, stimulus onset asynchrony (SOA), and stimuli type. Data from 39 studies yielded 87 individual effect sizes from 5,497 participants. Analyses revealed that stereotype priming is significantly moderated by the presence of prime-response relations, participant task, stereotype dimension, target stimulus type, SOA, and prime repetition. These results carry both practical and theoretical implications for future research on stereotype priming.

  17. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    International Nuclear Information System (INIS)

    Nogueira, P; Vaz, P; Zankl, M; Schlattl, H

    2011-01-01

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  18. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, P; Vaz, P [Technological and Nuclear Institute, Estrada Nacional No 10, 2686-953 Sacavem (Portugal); Zankl, M; Schlattl, H, E-mail: pedro.nogueira@helmholtz-muenchen.de [Helmholtz Zentrum Muenchen-German Research Center for Environmental Health, Research Unit Medical Radiation Physics and Diagnostics, Ingolstaedter Landstrasse 1, D-85764 Neuherberg (Germany)

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  19. Dose conversion coefficients for monoenergetic electrons incident on a realistic human eye model with different lens cell populations.

    Science.gov (United States)

    Nogueira, P; Zankl, M; Schlattl, H; Vaz, P

    2011-11-07

    The radiation-induced posterior subcapsular cataract has long been generally accepted to be a deterministic effect that does not occur at doses below a threshold of at least 2 Gy. Recent epidemiological studies indicate that the threshold for cataract induction may be much lower or that there may be no threshold at all. A thorough study of this subject requires more accurate dose estimates for the eye lens than those available in ICRP Publication 74. Eye lens absorbed dose per unit fluence conversion coefficients for electron irradiation were calculated using a geometrical model of the eye that takes into account different cell populations of the lens epithelium, together with the MCNPX Monte Carlo radiation transport code package. For the cell population most sensitive to ionizing radiation-the germinative cells-absorbed dose per unit fluence conversion coefficients were determined that are up to a factor of 4.8 higher than the mean eye lens absorbed dose conversion coefficients for electron energies below 2 MeV. Comparison of the results with previously published values for a slightly different eye model showed generally good agreement for all electron energies. Finally, the influence of individual anatomical variability was quantified by positioning the lens at various depths below the cornea. A depth difference of 2 mm between the shallowest and the deepest location of the germinative zone can lead to a difference between the resulting absorbed doses of up to nearly a factor of 5000 for electron energy of 0.7 MeV.

  20. Personality and Parkinson's disease: A meta-analysis.

    Science.gov (United States)

    Santangelo, Gabriella; Garramone, Federica; Baiano, Chiara; D'Iorio, Alfonsina; Piscopo, Fausta; Raimo, Simona; Vitale, Carmine

    2018-04-01

    Personality changes are considered pre-motor features of Parkinson's disease (PD). Cross-sectional studies revealed that PD patients were more introvert, apprehensive, and cautious than healthy subjects (HS), whereas other studies failed to disclose these behavioural traits. Some studies found mixed results concerning Novelty Seeking (NS) and Harm Avoidance (HA) profiles in PD patients. To better clarify the personality profile in PD we performed a meta-analysis on studies exploring such topic according to both Cloninger's Psychobiological Model (PM) and Big Five Model (BFM) METHODS: The meta-analysis included 17 studies evaluating the personality in PD patients compared with HS. The outcomes were the dimensions of the temperament and character of the PM and personality traits of BFM. Effect sizes from data reported in the primary studies were computed using Hedges'g unbiased approach. Heterogeneity among the studies and publication bias were assessed. Meta-regressions were conducted with age at evaluation, gender, schooling, and type of personality trait tools as moderators. As for PM, PD patients scored higher on HA and lower on NS than HS. No difference was found on Reward Dependence, Perseverance/Persistence and on character level. As for BFM, higher levels of Neuroticism, but lower levels of Openness and Extraversion were associated with PD. The personality profile in PD is characterized by high Neuroticism and HA, and by low Openness, Extraversion and NS. The personality profile delineated in the present study on PD patients seems to reflect the premorbid one and might contribute to development and persistence of affective disorders. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Time perception in depression: a meta-analysis.

    Science.gov (United States)

    Thönes, Sven; Oberfeld, Daniel

    2015-04-01

    Depressive patients frequently report to perceive time as going by very slowly. Potential effects of depression on duration judgments have been investigated mostly by means of four different time perception tasks: verbal time estimation, time production, time reproduction, and duration discrimination. Ratings of the subjective flow of time have also been obtained. By means of a classical random-effects meta-regression model and a robust variance estimation model, this meta-analysis aims at evaluating the inconsistent results from 16 previous studies on time perception in depression, representing data of 433 depressive patients and 485 healthy control subjects. Depressive patients perceive time as going by less quickly relative to control subjects (g=0.66, p=0.033). However, the analyses showed no significant effects of depression in the four time perception tasks. There was a trend towards inferior time discrimination performance in depression (g=0.38, p=0.079). The meta-regression also showed no significant effects of interval duration. Thus, the lack of effects of depression on timing does not depend on interval duration. However, for time production, there was a tendency towards overproduction of short and underproduction of long durations in depressive patients compared to healthy controls. Several aspects, such as influences of medication and the dopaminergic neurotransmitter system on time perception in depression, have not been investigated in sufficient detail yet and were therefore not addressed by this meta-analysis. Depression has medium effects on the subjective flow of time whereas duration judgments basically remain unaffected. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. A Western Dietary Pattern Increases Prostate Cancer Risk: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Fabiani, Roberto; Minelli, Liliana; Bertarelli, Gaia; Bacci, Silvia

    2016-10-12

    Dietary patterns were recently applied to examine the relationship between eating habits and prostate cancer (PC) risk. While the associations between PC risk with the glycemic index and Mediterranean score have been reviewed, no meta-analysis is currently available on dietary patterns defined by "a posteriori" methods. A literature search was carried out (PubMed, Web of Science) to identify studies reporting the relationship between dietary patterns and PC risk. Relevant dietary patterns were selected and the risks estimated were calculated by a random-effect model. Multivariable-adjusted odds ratios (ORs), for a first-percentile increase in dietary pattern score, were combined by a dose-response meta-analysis. Twelve observational studies were included in the meta-analysis which identified a "Healthy pattern" and a "Western pattern". The Healthy pattern was not related to PC risk (OR = 0.96; 95% confidence interval (CI): 0.88-1.04) while the Western pattern significantly increased it (OR = 1.34; 95% CI: 1.08-1.65). In addition, the "Carbohydrate pattern", which was analyzed in four articles, was positively associated with a higher PC risk (OR = 1.64; 95% CI: 1.35-2.00). A significant linear trend between the Western ( p = 0.011) pattern, the Carbohydrate ( p = 0.005) pattern, and the increment of PC risk was observed. The small number of studies included in the meta-analysis suggests that further investigation is necessary to support these findings.

  3. Visualizing the flow of evidence in network meta-analysis and characterizing mixed treatment comparisons.

    Science.gov (United States)

    König, Jochem; Krahn, Ulrike; Binder, Harald

    2013-12-30

    Network meta-analysis techniques allow for pooling evidence from different studies with only partially overlapping designs for getting a broader basis for decision support. The results are network-based effect estimates that take indirect evidence into account for all pairs of treatments. The results critically depend on homogeneity and consistency assumptions, which are sometimes difficult to investigate. To support such evaluation, we propose a display of the flow of evidence and introduce new measures that characterize the structure of a mixed treatment comparison. Specifically, a linear fixed effects model for network meta-analysis is considered, where the network estimates for two treatments are linear combinations of direct effect estimates comparing these or other treatments. The linear coefficients can be seen as the generalization of weights known from classical meta-analysis. We summarize properties of these coefficients and display them as a weighted directed acyclic graph, representing the flow of evidence. Furthermore, measures are introduced that quantify the direct evidence proportion, the mean path length, and the minimal parallelism of mixed treatment comparisons. The graphical display and the measures are illustrated for two published network meta-analyses. In these applications, the proposed methods are seen to render transparent the process of data pooling in mixed treatment comparisons. They can be expected to be more generally useful for guiding and facilitating the validity assessment in network meta-analysis. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Effect of Grape Polyphenols on Blood Pressure: A Meta-Analysis of Randomized Controlled Trials

    Science.gov (United States)

    Li, Shao-Hua; Zhao, Peng; Tian, Hong-Bo; Chen, Liang-Hua; Cui, Lian-Qun

    2015-01-01

    Background The effect of grape polyphenols on blood pressure remains unclear, which we aimed to address via a meta-analysis study. Methods We conducted study trial searches in PubMed, Embase, and the Cochrane Library databases. Summary estimates of weighted mean differences and 95% confidence intervals were obtained by using fixed-effects models. Subgroup analyses were performed to identify the source of heterogeneity. The protocol details of our meta-analysis have been submitted to the international database of prospectively registered systematic reviews (registration number CRD42015019196). Results Ten studies were included in the present meta-analysis. Our results showed daily grape polyphenol intake could significantly reduce systolic blood pressure by 1.48 mmHg when compared to control subjects (12 comparisons; -1.48 [-2.79 to -0.16] mmHg; P = 0.03). Subgroup analyses indicated larger reduction was identified in the intake of low-dose of grape polyphenols (grape polyphenols group as compared to controls. No significant heterogeneity or publication bias was detected in the meta-analysis of either systolic or diastolic blood pressure. Conclusions Daily grape polyphenol intake can significantly reduce the systolic blood pressure in humans, although the reduction is modest when compared with anti-hypertensive medications. Larger, better designed trials, that specifically include hypertensive subjects, are required to verify our results in the future. PMID:26375022

  5. Effect of Grape Polyphenols on Blood Pressure: A Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Li, Shao-Hua; Zhao, Peng; Tian, Hong-Bo; Chen, Liang-Hua; Cui, Lian-Qun

    2015-01-01

    The effect of grape polyphenols on blood pressure remains unclear, which we aimed to address via a meta-analysis study. We conducted study trial searches in PubMed, Embase, and the Cochrane Library databases. Summary estimates of weighted mean differences and 95% confidence intervals were obtained by using fixed-effects models. Subgroup analyses were performed to identify the source of heterogeneity. The protocol details of our meta-analysis have been submitted to the international database of prospectively registered systematic reviews (registration number CRD42015019196). Ten studies were included in the present meta-analysis. Our results showed daily grape polyphenol intake could significantly reduce systolic blood pressure by 1.48 mmHg when compared to control subjects (12 comparisons; -1.48 [-2.79 to -0.16] mmHg; P = 0.03). Subgroup analyses indicated larger reduction was identified in the intake of low-dose of grape polyphenols (grape polyphenols group as compared to controls. No significant heterogeneity or publication bias was detected in the meta-analysis of either systolic or diastolic blood pressure. Daily grape polyphenol intake can significantly reduce the systolic blood pressure in humans, although the reduction is modest when compared with anti-hypertensive medications. Larger, better designed trials, that specifically include hypertensive subjects, are required to verify our results in the future.

  6. Dietary vitamin B2 intake and breast cancer risk: a systematic review and meta-analysis.

    Science.gov (United States)

    Yu, Lanting; Tan, Yuyan; Zhu, Lin

    2017-03-01

    Epidemiological studies assessing the relationship between dietary vitamin B2 and the risk of breast cancer have produced inconsistent results. Thus, we conducted this meta-analysis of epidemiologic studies to evaluate this association. We searched English-language MEDLINE publications and conducted a manual search to screen eligible articles. A random-effect model was used to pool study-specific risk estimates. Egger's linear regression test was also used to detect publication bias in meta-analysis. In our meta-analysis, ten studies comprising totally 12,268 breast cancer patients were available in the analyses. Pooled relative risk (RR) comparing the highest to the lowest vitamin B2 intake and breast cancer incidence was 0.85 [95% confidence interval (CI) = 0.76-0.95]. No significant heterogeneity existed across the studies (P = 0.086, I 2  = 40.7%). No publication bias was found. The results of dose-response analysis also showed that an increment of 1 mg/day was inversely related to the risk of breast cancer (RR = 0.94; 95% CI = 0.90-0.99). Results from our meta-analysis indicated that dietary vitamin B2 intake is weakly related to the reduced risk of breast cancer. Additional research is also necessary to further explore this association.

  7. Prognostic Value of YKL-40 in Patients with Glioblastoma: a Systematic Review and Meta-analysis.

    Science.gov (United States)

    Qin, Gang; Li, Xianfeng; Chen, Zilong; Liao, Guangcha; Su, Yu; Chen, Yaode; Zhang, Wei

    2017-07-01

    YKL-40 is the most highly expressed gene in glioblastoma compared with normal brain tissues. Previous studies assessing the association between YKL-40 and survival in glioblastoma patients reported varying magnitude of estimates. The objective of this meta-analysis was to determine the prognostic value of YKL-40 in glioblastoma patients. PubMed and Embase databases were searched for studies relating to YKL-40 and prognosis of glioblastoma patients. Studies reporting estimates for overall survival by YKL-40 expression in glioblastoma patients were considered eligible. A meta-analysis of included studies was performed using fixed- or random-effect model to calculate the pooled hazard ratio (HR) and 95 % confidence interval (95%CI). Eight studies were ultimately considered eligible and included into the meta-analysis. Those eight studies included 1241 glioblastoma patients. Meta-analysis of those studies showed that high YKL-40 expression was associated with worse overall survival in glioblastoma patients (HR = 1.46, 95%CI 1.33-1.61, P 40 expression was independently associated with worse overall survival in glioblastoma patients (HR = 1.50, 95%CI 1.35-1.66, P 40 expression and worse overall survival in glioblastoma patients. High YKL-40 expression is independently and markedly associated with worse overall survival in glioblastoma patients. YKL-40 is a good predictive biomarker of prognosis in glioblastoma patients.

  8. Association between increase in fixed penalties and road safety outcomes: A meta-analysis.

    Science.gov (United States)

    Elvik, Rune

    2016-07-01

    Studies that have evaluated the association between increases in traffic fine amounts (fixed penalties) and changes in compliance with road traffic law or the number of accidents are synthesised by means of meta-analysis. The studies were few and different in many respects. Nine studies were included in the meta-analysis of changes in compliance. Four studies were included in the meta-analysis of changes in accidents. Increasing traffic fines was found to be associated with small changes in the rate of violations. The changes were non-linear. For increases up to about 100%, violations were reduced. For larger increases, no reduction in violations was found. A small reduction in fatal accidents was associated with increased fixed penalties, varying between studies from less than 1-12%. The main pattern of changes in violations was similar in the fixed-effects and random-effects models of meta-analysis, meta-regression and when simple (non-weighted) mean values were computed. The main findings are thus robust, although most of the primary studies did not control very well for potentially confounding factors. Summary estimates of changes in violations or accidents should be treated as provisional and do not necessarily reflect causal relationships. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Legume intake and risk of prostate cancer: a meta-analysis of prospective cohort studies.

    Science.gov (United States)

    Li, Jie; Mao, Qi-Qi

    2017-07-04

    Previous studies regarding the relationship between legume intake and risk of prostate cancer have reported inconsistent results. We conducted a meta-analysis of prospective cohort studies to summarize evidence on this association. A systematic literature search of articles published through June 2016 was performed using PubMed and Web of Science databases. The combined relative risk (RR) with its 95% confidence interval (CI) for the highest versus the lowest intake of legumes was calculated with a random-effects model. Dose-response meta-analysis was also performed for the studies that provided at least three levels of legume consumption. Ten articles (eight cohorts) reporting 281,034 individuals and 10,234 incident cases were identified. The individuals with high consumption of legumes compared with the reference group experienced a significantly reduced risk for developing prostate cancer (RR: 0.85 [95% CI 0.75-0.96], P = 0.010). Moderate heterogeneity of RRs was observed across these studies (P = 0.064 for heterogeneity, I2 = 45.8 %). Dose-response meta-analysis indicated that the risk of prostate cancer reduced by 3.7% (95% CI 1.5%-5.8%) for each 20 grams per day increment of legume intake. In conclusion, the results from this meta-analysis suggest that a high intake of legumes is associated with a low incidence of prostate cancer.

  10. A refined method for multivariate meta-analysis and meta-regression

    Science.gov (United States)

    Jackson, Daniel; Riley, Richard D

    2014-01-01

    Making inferences about the average treatment effect using the random effects model for meta-analysis is problematic in the common situation where there is a small number of studies. This is because estimates of the between-study variance are not precise enough to accurately apply the conventional methods for testing and deriving a confidence interval for the average effect. We have found that a refined method for univariate meta-analysis, which applies a scaling factor to the estimated effects’ standard error, provides more accurate inference. We explain how to extend this method to the multivariate scenario and show that our proposal for refined multivariate meta-analysis and meta-regression can provide more accurate inferences than the more conventional approach. We explain how our proposed approach can be implemented using standard output from multivariate meta-analysis software packages and apply our methodology to two real examples. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons, Ltd. PMID:23996351

  11. Physical Activity and Cognitive Development: A Meta-Analysis.

    Science.gov (United States)

    Jackson, William M; Davis, Nicholas; Sands, Stephen A; Whittington, Robert A; Sun, Lena S

    2016-10-01

    inclusion. From these 18 studies, 8 were independently selected by 2 authors for inclusion in the final analysis; there were no selection discrepancies between authors with regard to the studies to be included. In all, 770 subjects were included, 339 in the control group and 431 in the intervention group. All 8 studies contained a measure of inhibitory control; no other domain of executive function was measured frequently enough to perform meta-analysis, so only measures of inhibitory control were pooled and analyzed. A Cohen d effect size was calculated for each measure using the method of Morris for controlled pre-post control measurement studies. The studies were then combined in a random effects model using Comprehensive Meta Analysis software (Biostat, Englewood, NJ) for Windows (Microsoft, Redmond, WA). All studies showed a positive effect of regular exercise with improvements in measures of inhibitory control, but none were statistically significant for this measure. When pooled, the model revealed a combined Cohen d effect size of 0.2 (95% confidence interval, 0.03-0.37; P=0.021), indicating a small improvement of inhibitory control with long-term physical activity. Heterogeneity was very low (I=0). Many studies used different neuropsychological tests to assess inhibitory control, which may have introduced unforeseen confounders. Other domains of executive functions were not measured frequently enough to perform meta-analysis. Despite attempts to gather unpublished data, positive results were observed in all of the included studies, raising the possibility of publication bias. Increased regular physical activity is associated with a small and measurable, improvement in neuropsychological tests of executive functions, specifically inhibitory control. Executive functions play an important role in complex behavior, and may contribute to academic and career achievement as well as success in social interaction. This finding provides support for the important interaction

  12. Quantitative Ultrasound and bone's response to exercise: a meta analysis.

    Science.gov (United States)

    Babatunde, O O; Forsyth, J J

    2013-03-01

    The utility of Quantitative Ultrasound (QUS) for assessing and monitoring changes in bone health due to exercise is limited for lack of adequate research evidence. Restrictions to bone density testing and the enduring debate over repeat dual energy absorptiometry testing spells uncertainty over clinical and non-clinical evaluation of exercise for prevention of osteoporosis. This study, via systematic review and meta-analysis, aimed to paint a portrait of current evidence regarding QUS' application to monitoring bone's adaptive response to exercise interventions. Structured and comprehensive search of databases was undertaken along with hand-searching of key journals and reference lists to locate relevant studies published up to December 2011. Twelve articles met predetermined inclusion criteria. The effect of exercise interventions for improving bone health, as measured by QUS of the calcaneum, was examined across the age spectrum. Study outcomes for analysis: absolute (dB/MHz) or relative change (%) in broadband ultrasound attenuation (BUA) and/or os calcis stiffness index were compared by calculating standardised mean difference (SMD) using fixed- and random-effects models. Quality of included trials varied from low to high on a scale of one to three. Four to 36months of exercise led to a significant improvement in calcaneum BUA (0.98 SMD, 95% CI 0.80, 1.16, overall effect Z-value=10.72, p=0.001) across the age spectrum. The meta-analysis attests to the sensitivity of QUS to exercise-induced changes in bone health across the age groups. QUS may be considered for use in exercise-based bone health interventions for preventing osteoporosis. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Meta-Analysis of Surgeon Burnout Syndrome and Specialty Differences.

    Science.gov (United States)

    Bartholomew, Alex J; Houk, Anna K; Pulcrano, Marisa; Shara, Nawar M; Kwagyan, John; Jackson, Patrick G; Sosin, Michael

    2018-02-27

    Surgeon burnout compromises the quality of life of physicians and the delivery of care to patients. Burnout rates and interpretation of the Maslach Burnout Inventory (MBI) complicates the interpretation of surgeon burnout. The purpose of this study is to apply a standardized interpretation of severe surgeon burnout termed, "burnout syndrome" to analyze inherent variation within surgical specialties. A systematic literature search was performed using MEDLINE, PsycINFO, and EMBASE to identify studies reporting MBI data by surgical specialty. Data extraction was performed to isolate surgeon specific data. A meta-analysis was performed. A total of 16 cross-sectional studies were included in this meta-analysis, totaling 3581 subjects. A random effects model approximated burnout syndrome at 3.0% (95% CI: 2.0%-5.0%; I 2 = 78.1%). Subscale analysis of emotional exhaustion, depersonalization, and personal accomplishment indicated subscale burnout in 30.0% (CI: 25.0%-36.0%; I 2 = 93.2%), 34.0% (CI: 25.0%-43.0%; I 2 = 96.9%), and 25.0% (CI: 18.0%-32.0%; I 2 = 96.5%) of surgeons, respectively. Significant differences (p burnout termed "burnout syndrome," although surgeon burnout may occur in up to 34% of surgeons, characterized by high burnout in 1 of 3 subscales. Surgical specialties have significantly different rates of burnout subscales. Future burnout studies should target the specialty-specific level to understand inherent differences in an effort to better understand methods of improving surgeon burnout. Copyright © 2018 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

  14. A determination of H-0 with the class gravitational lens B1608+656. II. Mass models and the Hubble constant from lensing

    NARCIS (Netherlands)

    Koopmans, LVE; Fassnacht, CD

    1999-01-01

    We present mass models of the four-image gravitational lens system B1608 + 656, based on information obtained through VLBA imaging, VLA monitoring, and Hubble Space Telescope (HST) WFPC2 and NICMOS imaging. We have determined a mass model for the lens galaxies that reproduces (1) all image positions

  15. An overview of meta-analysis for clinicians

    Science.gov (United States)

    Lee, Young Ho

    2018-01-01

    The number of medical studies being published is increasing exponentially, and clinicians must routinely process large amounts of new information. Moreover, the results of individual studies are often insufficient to provide confident answers, as their results are not consistently reproducible. A meta-analysis is a statistical method for combining the results of different studies on the same topic and it may resolve conflicts among studies. Meta-analysis is being used increasingly and plays an important role in medical research. This review introduces the basic concepts, steps, advantages, and caveats of meta-analysis, to help clinicians understand it in clinical practice and research. A major advantage of a meta-analysis is that it produces a precise estimate of the effect size, with considerably increased statistical power, which is important when the power of the primary study is limited because of a small sample size. A meta-analysis may yield conclusive results when individual studies are inconclusive. Furthermore, meta-analyses investigate the source of variation and different effects among subgroups. In summary, a meta-analysis is an objective, quantitative method that provides less biased estimates on a specific topic. Understanding how to conduct a meta-analysis aids clinicians in the process of making clinical decisions. PMID:29277096

  16. Oceanic island biogeography through the lens of the general dynamic model

    DEFF Research Database (Denmark)

    Borregaard, Michael Krabbe; Amorim, Isabel R.; Borges, Paulo A. V.

    2017-01-01

    The general dynamic model of oceanic island biogeography (GDM) has added a new dimension to theoretical island biogeography in recognizing that geological processes are key drivers of the evolutionary processes of diversification and extinction within remote islands. It provides a dynamic...... and essentially non-equilibrium framework generating novel predictions for emergent diversity properties of oceanic islands and archipelagos. Its publication in 2008 coincided with, and spurred on, renewed attention to the dynamics of remote islands. We review progress, both in testing the GDM's predictions...... and in developing and enhancing ecological-evolutionary understanding of oceanic island systems through the lens of the GDM. In particular, we focus on four main themes: (i) macroecological tests using a space-for-time rationale; (ii) extensions of theory to islands following different patterns of ontogeny; (iii...

  17. Meta-analysis: Problems with Russian Publications.

    Science.gov (United States)

    Verbitskaya, E V

    2015-01-01

    Meta-analysis is a powerful tool to identify Evidence Based medical technologies (interventions) for use in every day practice. Meta-analysis uses statistical approaches to combine results from multiple studies in an effort to increase power (over individual studies), improve estimates of the size of the effect and/or to resolve uncertainty when reports disagree. Meta-analysis is a quantitative, formal study design used to systematically assess previous research studies to derive conclusions from this research. Meta-analysis may provide more precise estimate of the effect of treatment or risk factor for a disease, or other outcomes, than any individual study contributing to the pooled analysis.We have quite a substantial number of Russian medical publications, but not so many Meta-Analyses published in Russian. Russian publications are cited in English language papers not so often. A total of 90% of clinical studies included in published Meta-Analyses incorporate only English language papers. International studies or papers with Russian co-authors are published in English language. The main question is: what is the problem with inclusion of Russian medical publications in Meta-Analysis? The main reasons for this are the following: 1) It is difficult to find Russian papers, difficult to work with them and to work with Russian journals:a. There are single Russian Biomedical Journals, which are translated into English and are included in databases (PubMed, Scopus and other), despite the fact that all of them have English language abstracts.b. The majority the meta-analyses authors use in their work different citation management software such as the Mendeley, Reference Manager, ProCite, EndNote, and others. These citation management systems allow scientists to organize their own literature databases with internet searches and have adds-on for the Office programs what makes process of literature citation very convenient. The Internet sites of the majority of

  18. Effect of soy isoflavone supplementation on plasma lipoprotein(a) concentrations: A meta-analysis.

    Science.gov (United States)

    Simental-Mendía, Luis E; Gotto, Antonio M; Atkin, Stephen L; Banach, Maciej; Pirro, Matteo; Sahebkar, Amirhossein

    Soy supplementation has been shown to reduce total and low-density lipoprotein cholesterol, while increasing high-density lipoprotein cholesterol. However, contradictory effects of soy isoflavone supplementation on lipoprotein(a) [Lp(a)] have been reported suggesting the need for a meta-analysis to be undertaken. The aim of the study was to investigate the impact of supplementation with soy isoflavones on plasma Lp(a) levels through a systematic review and meta-analysis of eligible randomized placebo-controlled trials. The search included PubMed-Medline, Scopus, ISI Web of Knowledge, and Google Scholar databases (by March 26, 2017), and quality of studies was evaluated according to Cochrane criteria. Quantitative data synthesis was performed using a random-effects model, with standardized mean difference and 95% confidence interval as summary statistics. Meta-regression and leave-one-out sensitivity analysis were performed to assess the modifiers of treatment response. Ten eligible studies comprising 11 treatment arms with 973 subjects were selected for the meta-analysis. Meta-analysis did not suggest any significant alteration of plasma Lp(a) levels after supplementation with soy isoflavones (standardized mean difference: 0.08, 95% confidence interval: -0.05, 0.20, P = .228). The effect size was robust in the leave-one-out sensitivity analysis. In meta-regression analysis, neither dose nor duration of supplementation with soy isoflavones was significantly associated with the effect size. This meta-analysis of the 10 available randomized placebo-controlled trials revealed no significant effect of soy isoflavones treatment on plasma Lp(a) concentrations. Copyright © 2017 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  19. Macroeconomics of Natural Disasters: Strengths and Weaknesses of Meta-Analysis Versus Review of Literature.

    Science.gov (United States)

    A G van Bergeijk, Peter; Lazzaroni, Sara

    2015-06-01

    We use the case of the macroeconomic impact of natural disasters to analyze strengths and weaknesses of meta-analysis in an emerging research field. Macroeconomists have published on this issue since 2002 (we identified 60 studies to date). The results of the studies are contradictory and therefore the need to synthesize the available research is evident. Meta-analysis is a useful method in this field. An important aim of our article is to show how one can use the identified methodological characteristics to better understand the robustness and importance of new findings. To provide a comparative perspective, we contrast our meta-analysis and its findings with the major influential research synthesis in the field: the IPCC's 2012 special report Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation. We show that the IPCC could have been more confident about the negative economic impact of disasters and more transparent on inclusion and qualification of studies, if it had been complemented by a meta-analysis. Our meta-analysis shows that, controlling for modeling strategies and data set, the impact of disasters is significantly negative. The evidence is strongest for direct costs studies where we see no difference between our larger sample and the studies included in the IPCC report. Direct cost studies and indirect cost studies differ significantly, both in terms of the confidence that can be attached to a negative impact of natural disasters and in terms of the sources of heterogeneity of the findings reported in the primary studies. © 2015 Society for Risk Analysis.

  20. Intermittent Cervical Traction for Treating Neck Pain: A Meta-analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Yang, Jheng-Dao; Tam, Ka-Wai; Huang, Tsai-Wei; Huang, Shih-Wei; Liou, Tsan-Hon; Chen, Hung-Chou

    2017-07-01

    A meta-analysis. The aim of this study was to perform a comprehensive search of current literature and conduct a meta-analysis of randomized controlled trials (RCTs) to assess the neck pain relieving effect of intermittent cervical traction (ICT). Neck pain is a common and disabling problem with a high prevalence in general population. It causes a considerable burden on the health care system with a substantial expenditure. ICT is a common component of physical therapy for neck pain in the outpatient clinic. However, the evidence regarding the effectiveness of ICT for neck pain is insufficient. Data were obtained from the PubMed, Cochrane Library, Embase, and Scopus databases from the database inception date to July 02, 2016. RCTs reporting the effects of ICT on neck pain, including those comparing the effects of ICT with those of a placebo treatment, were included. Two reviewers independently reviewed the studies, conducted a risk of bias assessment, and extracted data. The data were pooled in a meta-analysis by using a random-effects model. The meta-analysis included seven RCTs. The results indicated that patients who received ICT for neck pain had significantly lower pain scores than those receiving placebos did immediately after treatment (standardized mean difference = -0.26, 95% confidence interval = -0.46 to -0.07). The pain scores during the follow-up period and the neck disability index scores immediately after treatment and during the follow-up period did not differ significantly. ICT may have a short-term neck pain-relieving effect. Some risks of bias were noted in the included studies, reducing the evidence level of this meta-analysis. Additional high-quality RCTs are required to clarify the long-term effects of ICT on neck pain. 1.

  1. Meta-analysis of Gaussian individual patient data: Two-stage or not two-stage?

    Science.gov (United States)

    Morris, Tim P; Fisher, David J; Kenward, Michael G; Carpenter, James R

    2018-04-30

    Quantitative evidence synthesis through meta-analysis is central to evidence-based medicine. For well-documented reasons, the meta-analysis of individual patient data is held in higher regard than aggregate data. With access to individual patient data, the analysis is not restricted to a "two-stage" approach (combining estimates and standard errors) but can estimate parameters of interest by fitting a single model to all of the data, a so-called "one-stage" analysis. There has been debate about the merits of one- and two-stage analysis. Arguments for one-stage analysis have typically noted that a wider range of models can be fitted and overall estimates may be more precise. The two-stage side has emphasised that the models that can be fitted in two stages are sufficient to answer the relevant questions, with less scope for mistakes because there are fewer modelling choices to be made in the two-stage approach. For Gaussian data, we consider the statistical arguments for flexibility and precision in small-sample settings. Regarding flexibility, several of the models that can be fitted only in one stage may not be of serious interest to most meta-analysis practitioners. Regarding precision, we consider fixed- and random-effects meta-analysis and see that, for a model making certain assumptions, the number of stages used to fit this model is irrelevant; the precision will be approximately equal. Meta-analysts should choose modelling assumptions carefully. Sometimes relevant models can only be fitted in one stage. Otherwise, meta-analysts are free to use whichever procedure is most convenient to fit the identified model. © 2018 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  2. Ischiofemoral impingement syndrome: a meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Singer, Adam D.; Subhawong, Ty K.; Jose, Jean; Tresley, Jonathan; Clifford, Paul D. [Jackson Memorial Hospital, Department of Diagnostic Radiology, Section of Musculoskeletal Imaging, Miami, FL (United States)

    2015-06-01

    The aims of this article are to review the imaging characteristics of ischiofemoral impingement (IFI), summarize measurement thresholds for radiologic diagnosis based on a meta-analysis of the literature and raise awareness among radiologists and clinicians of this entity. A PubMed search restricted to the English language containing the keywords ''ischiofemoral impingement'' and ''quadratus femoris MRI'' was performed, and citations in these articles were also used to identify a total of 27 studies discussing ischiofemoral impingement. After excluding case reports and non-representative studies, there were five remaining articles including 193 hip MRIs of IFI in 154 subjects (133 female, 21 male) and 135 asymptomatic control hip MRIs from 74 subjects (55 female, 19 male). Additionally, we performed a retrospective database search of pelvic and hip MRI reports from our institution including the terms ''quadratus femoris'' or ''ischiofemoral impingement'' from a 9-year period and 24 hip MRIs from 21 patients (18 female, 3 male) with IFI with 5 asymptomatic contralateral control hip MRIs identified. In all, 217 hip MRIs of IFI and 140 control cases were included. A meta-analysis of these hip MRIs was conducted to determine optimal thresholds of the ischiofemoral space (IFS) and quadratus femoris space (QFS) for identifying IFI. Cases of IFI showed significantly smaller IFS and QFS compared to controls (14.91 ± 4.8 versus 26.01 ± 7.98 and 9.57 ± 3.7 versus 15.97 ± 6.07, measured in mm, respectively, p < 0.0001 for both). Pooled analysis revealed that for IFS, using a cutoff of ≤15 mm yielded a sensitivity of 76.9 %, specificity of 81.0 % and overall accuracy of 78.3 %. For QFS, a cutoff of ≤ 10.0 mm resulted in 78.7 % sensitivity, 74.1 % specificity and 77.1 % overall accuracy. IFI is a potential cause of hip pain that can be accurately diagnosed with MRI in conjunction with

  3. Meniscal allograft transplantation: a meta-analysis

    Directory of Open Access Journals (Sweden)

    De Bruycker Manolito

    2017-01-01

    Full Text Available Purpose: This meta-analysis evaluates the mid- to long-term survival outcome of MAT (meniscal allograft transplantation. Potential prognosticators, with particular focus on chondral status and age of the patient at the time of transplantation, were also analysed. Study design: Meta-analysis. Methods: An online database search was performed using following search string: “meniscal allograft transplantation” and “outcome”. A total of 65 articles were analysed for a total of 3157 performed MAT with a mean follow-up of 5.4 years. Subjective and clinical data was analysed. Results: The subjective and objective results of 2977 patients (3157 allografts were analysed; 70% were male, 30% were female. Thirty-eight percent received an isolated MAT. All other patients underwent at least one concomitant procedure. Lysholm, Knee injury and Osteoarthritis Outcome (KOOS, International Knee Documentation Committee (IKDC and Visual Analogue Scale (VAS scores were analysed. All scores showed a good patient satisfaction at long-term follow-up. The mean overall survival rate was 80.9%. Complication rates were comparable to standard meniscal repair surgery. There was a degenerative evolution in osteoarthritis with at least one grade in 1760 radiographically analysed patients. Concomitant procedures seem to have no effect on the outcome. Age at transplantation is a negative prognosticator. The body mass index (BMI of the patient shows a slightly negative correlation with the outcome of MAT. Conclusions: MAT is a viable solution for the younger patient with chronic pain in the meniscectomised knee joint. The complications are not severe and comparable to meniscal repair. The overall failure rate at final follow-up is acceptable and the allograft heals well in most cases, but MAT cannot be seen as a definitive solution for post-meniscectomy pain. The correct approach to the chronic painful total meniscectomised knee joint thus requires consideration of all

  4. Effect of chamber stabilization software on efficiency and chatter in a porcine lens model.

    Science.gov (United States)

    Wright, Alex J; Thomson, Rhett S; Bernhisel, Ashlie A; Zaugg, Brian; Barlow, William R; Pettey, Jeff H; Olson, Randall J

    2017-11-01

    To evaluate the effects of the use of programmable chamber stabilization software (Chamber Stabilization Environment) settings on efficiency and chatter in a porcine lens model. John A. Moran Eye Center Laboratory, University of Utah, Salt Lake City, Utah, USA. Experimental study. Porcine eyes were dissected and the lenses extracted. The lenses were then hardened and processed for the experiment. Phacoemulsification of the lens fragments was performed with the Whitestar Signature Pro with the Whitestar handpiece and a 0.9 mm straight Dewey tip with a 30-degree bevel. All arms of the study were run in peristaltic mode with 50 mL/minute aspiration, 100 cm bottle height, and on 100% power. The chamber stabilization software setting was used for each of the 4 study arms with a maximum vacuum of 500 mm Hg. Arm 1 included 20 runs with the up time set to 2000 milliseconds. Arm 2 was performed with similar settings but with an up time of 0 millisecond. Arms 3 and 4 were run with up times of 1000 milliseconds and 500 milliseconds, respectively. The mean efficiency time of each run was as follows: 0 millisecond = 1.4 seconds, 500 milliseconds = 0.95 seconds, 1000 milliseconds = 0.88 seconds, 2000 milliseconds = 0.93 seconds. When compared with 0 millisecond, each of the other arms were significantly faster. Chatter events were comparable between the study arms. The chamber stabilization software does not decrease efficiency when compared with full vacuum on if at least 500 milliseconds of up time is maintained. Copyright © 2017 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  5. The preferentially magnified active nucleus in IRAS F10214+4724 - I. Lens model and spatially resolved radio emission

    Science.gov (United States)

    Deane, R. P.; Rawlings, S.; Marshall, P. J.; Heywood, I.; Klöckner, H.-R.; Grainge, K.; Mauch, T.; Serjeant, S.

    2013-03-01

    This is the first paper in a series that presents a multiwavelength analysis of the archetype ultraluminous infrared galaxy IRAS F10214+4724, a gravitationally lensed, starburst/active galactic nucleus at z = 2.3. Here we present a new lens model and spatially resolved radio data, as well as a deep Hubble Space Telescope (HST) F160W map. The lens modelling employs a Bayesian Markov chain Monte Carlo algorithm with extended source, forward ray tracing. Using these high-resolution HST, Multi-Element Radio Linked Interferometer Network (MERLIN) and Very Large Array (VLA) maps, the algorithm allows us to constrain the level of distortion to the continuum spectral energy distribution resulting from emission components with differing magnification factors, due to their size and proximity to the caustic. Our lens model finds that the narrow-line region, and by proxy the active nucleus, is preferentially magnified. This supports previous claims that preferential magnification could mask the expected polycyclic aromatic hydrocarbon spectral features in the Spitzer mid-infrared spectrum which roughly trace the star-forming regions. Furthermore, we show that the arc-to-counter-image flux ratio is not a good estimate of the magnification in this system, despite its common use in the IRAS F10214+4724 literature. Our lens modelling suggests magnifications of μ ˜ 15-20 ± 2 for the HST F814W, MERLIN 1.7 GHz and VLA 8 GHz maps, significantly lower than the canonical values of μ = 50-100 often used for this system. Systematic errors such as the dark matter density slope and colocation of stellar and dark matter centroids dominate the uncertainties in the lens model at the 40 per cent level.

  6. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    Directory of Open Access Journals (Sweden)

    Yasser A. Abdel-Hadi

    2015-12-01

    Full Text Available A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52′N, longitude λ = 31°21′E and elevation = 141 m as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC, while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC. The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  7. Simulation model of a new solar laser system of Fresnel lens according to real observed solar radiation data in

    Science.gov (United States)

    Abdel-Hadi, Yasser A.; Ghitas, A.; Abulwfa, A.; Sabry, M.

    2015-12-01

    A new simulation model of a new solar pumped laser system was tested to be run in Helwan in Egypt (latitude φ = 29°52‧N, longitude λ = 31°21‧E and elevation = 141 m) as an example of an industrial polluted area. The system is based on concentrating the solar radiation using a Fresnel lens on a laser head fixed on a mount tracking the sun during the day and powered by a DC battery. Two cases of this model are tested; the first one is the model consisting of a Fresnel lens and a two-dimensional Compound Parabolic Concentrator (CPC), while the other is the model consisting of a Fresnel lens and a three-dimensional Compound Parabolic Concentrator (CPC). The model is fed by real actual solar radiation data taken in Helwan Solar Radiation Station at NRIAG in the various seasons in order to know the laser power got from such a system in those conditions. For the system of Fresnel lens and 2D-CPC, an average laser output power of 1.27 W in Winter, 2 W in Spring, 5 W in Summer and 4.68 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 3.24 W. For the system of Fresnel lens and 3D-CPC, an average laser output power of 3.28 W in Winter, 3.55 W in Spring, 7.56 W in Summer and 7.13 W in Autumn respectively can be obtained. Accordingly, the annual average output power for this system is 5.38 W.

  8. A Systematic Review and Meta-analysis of the Association Between Giardia lamblia and Endemic Pediatric Diarrhea in Developing Countries

    Science.gov (United States)

    Muhsen, Khitam; Levine, Myron M.

    2012-01-01

    We performed a systematic literature review and meta-analysis examining the association between diarrhea in young children in nonindustrialized settings and Giardia lamblia infection. Eligible were case/control and longitudinal studies that defined the outcome as acute or persistent (>14 days) diarrhea, adjusted for confounders and lasting for at least 1 year. Data on G. lamblia detection (mainly in stools) from diarrhea patients and controls without diarrhea were abstracted. Random effects model meta-analysis obtained pooled odds ratios (ORs) and 95% confidence intervals (CIs). Twelve nonindustrialized-setting acute pediatric diarrhea studies met the meta-analysis inclusion criteria. Random-effects model meta-analysis of combined results (9774 acute diarrhea cases and 8766 controls) yielded a pooled OR of 0.60 (95% CI, .38–.94; P = .03), indicating that G. lamblia was not associated with acute diarrhea. However, limited data suggest that initial Giardia infections in early infancy may be positively associated with diarrhea. Meta-analysis of 5 persistent diarrhea studies showed a pooled OR of 3.18 (95% CI, 1.50–6.76; P diarrhea in children in developing countries. PMID:23169940

  9. A Meta-Analysis of the Relations among Training Criteria

    National Research Council Canada - National Science Library

    Alliger, George

    1998-01-01

    .... Meta-analysis results among criteria using this framework include the finding of substantial reliabilities across training criteria and reasonable convergence among subdivisions of criteria within a larger level...

  10. Meta-Analysis of Complex Interventions.

    Science.gov (United States)

    Tanner-Smith, Emily E; Grant, Sean

    2018-04-01

    Meta-analysis is a prominent method for estimating the effects of public health interventions, yet these interventions are often complex in ways that pose challenges to using conventional meta-analytic methods. This article discusses meta-analytic techniques that can be used in research syntheses on the effects of complex public health interventions. We first introduce the use of complexity frameworks to conceptualize public health interventions. We then present a menu of meta-analytic procedures for addressing various sources of complexity when answering questions about the effects of public health interventions in research syntheses. We conclude with a review of important practices and key resources for conducting meta-analyses on complex interventions, as well as future directions for research synthesis more generally. Overall, we argue that it is possible to conduct meaningful quantitative syntheses of research on the effects of public health interventions, though these meta-analyses may require the use of advanced techniques to properly consider and attend to issues of complexity.

  11. Energy consumption and economic growth—New evidence from meta analysis

    International Nuclear Information System (INIS)

    Chen, Ping-Yu; Chen, Sheng-Tung; Chen, Chi-Chung

    2012-01-01

    The causal relationships between energy consumption and economic growth have given rise to much discussion but remain controversial. Alternative data sets based on different time spans, countries, energy policies and econometric approaches result in diverse outcomes. A meta analysis using a multinomial logit model with 174 samples governing the relationships between GDP and energy consumption is applied here to investigate the major factors that affect these controversial outcomes. The empirical results have demonstrated how the time spans, subject selections including GDP and energy consumption, econometric models, and tools for greenhouse gases emission reduction characteristics significantly affect these controversial outcomes. - Highlights: ► The controversial casual relationships between energy consumption and GDP are investigated. ► A meta analysis using a multinomial logit model is adopted. ► 74 studies governing the relationships between GDP and energy consumption was collected. ► The empirical results show how the probability of major factors affects such relationships.

  12. The Neural Correlates of Moral Thinking: A Meta-Analysis

    OpenAIRE

    Douglas J. Bryant; Wang F; Kelley Deardeuff; Emily Zoccoli; Chang S. Nam

    2016-01-01

    We conducted a meta-analysis to evaluate current research that aims to map the neural correlates of two typical conditions of moral judgment: right-wrong moral judgments and decision-making in moral dilemmas. Utilizing the activation likelihood estimation (ALE) method, we conducted a meta-analysis using neuroimaging data obtained from twenty-one previous studies that measured responses in one or the other of these conditions. We found that across the studies (n = 400), distinct neural circuit...

  13. Meta-analysis of DNA methylation biomarkers in hepatocellular carcinoma

    OpenAIRE

    Zhang, Cheng; Li, Jinyun; Huang, Tao; Duan, Shiwei; Dai, Dongjun; Jiang, Danjie; Sui, Xinbing; Li, Da; Chen, Yidan; Ding, Fei; Huang, Changxin; Chen, Gongying; Wang, Kaifeng

    2016-01-01

    DNA methylation is an epigenetic mechanism in the pathogenesis of hepatocellular carcinoma (HCC). Here, we conducted a systematic meta-analysis to evaluate the contribution of DNA methylation to the risk of HCC. A total of 2109 publications were initially retrieved from PubMed, Web of Science, Cochrane Library, Embase, CNKI and Wanfang literature database. After a four-step filtration, we harvested 144 case-control articles in the meta-analysis. Our results revealed that 24 genes (carcinoma t...

  14. Combining multiple imputation and meta-analysis with individual participant data.

    Science.gov (United States)

    Burgess, Stephen; White, Ian R; Resche-Rigon, Matthieu; Wood, Angela M

    2013-11-20

    Multiple imputation is a strategy for the analysis of incomplete data such that the impact of the missingness on the power and bias of estimates is mitigated. When data from multiple studies are collated, we can propose both within-study and multilevel imputation models to impute missing data on covariates. It is not clear how to choose between imputation models or how to combine imputation and inverse-variance weighted meta-analysis methods. This is especially important as often different studies measure data on different variables, meaning that we may need to impute data on a variable which is systematically missing in a particular study. In this paper, we consider a simulation analysis of sporadically missing data in a single covariate with a linear analysis model and discuss how the results would be applicable to the case of systematically missing data. We find in this context that ensuring the congeniality of the imputation and analysis models is important to give correct standard errors and confidence intervals. For example, if the analysis model allows between-study heterogeneity of a parameter, then we should incorporate this heterogeneity into the imputation model to maintain the congeniality of the two models. In an inverse-variance weighted meta-analysis, we should impute missing data and apply Rubin's rules at the study level prior to meta-analysis, rather than meta-analyzing each of the multiple imputations and then combining the meta-analysis estimates using Rubin's rules. We illustrate the results using data from the Emerging Risk Factors Collaboration. © 2013 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

  15. Combining multiple imputation and meta-analysis with individual participant data

    Science.gov (United States)

    Burgess, Stephen; White, Ian R; Resche-Rigon, Matthieu; Wood, Angela M

    2013-01-01

    Multiple imputation is a strategy for the analysis of incomplete data such that the impact of the missingness on the power and bias of estimates is mitigated. When data from multiple studies are collated, we can propose both within-study and multilevel imputation models to impute missing data on covariates. It is not clear how to choose between imputation models or how to combine imputation and inverse-variance weighted meta-analysis methods. This is especially important as often different studies measure data on different variables, meaning that we may need to impute data on a variable which is systematically missing in a particular study. In this paper, we consider a simulation analysis of sporadically missing data in a single covariate with a linear analysis model and discuss how the results would be applicable to the case of systematically missing data. We find in this context that ensuring the congeniality of the imputation and analysis models is important to give correct standard errors and confidence intervals. For example, if the analysis model allows between-study heterogeneity of a parameter, then we should incorporate this heterogeneity into the imputation model to maintain the congeniality of the two models. In an inverse-variance weighted meta-analysis, we should impute missing data and apply Rubin's rules at the study level prior to meta-analysis, rather than meta-analyzing each of the multiple imputations and then combining the meta-analysis estimates using Rubin's rules. We illustrate the results using data from the Emerging Risk Factors Collaboration. PMID:23703895

  16. Effect of Metformin on Plasma Fibrinogen Concentrations: A Systematic Review and Meta-Analysis of Randomized Placebo-Controlled Trials.

    Science.gov (United States)

    Simental-Mendia, Luis E; Pirro, Matteo; Atkin, Stephen L; Banach, Maciej; Mikhailidis, Dimitri P; Sahebkar, Amirhossein

    2017-11-03

    Fibrinogen is a key mediator of thrombosis and it has been implicated in the pathogenesis of atherosclerosis. Because metformin has shown a potential protective effect on different atherothrombotic risk factors, we assessed in this meta-analysis its effect on plasma fibrinogen concentrations. A systematic review and meta-analysis was carried out to identify randomized placebo-controlled trials evaluating the effect of metformin administration on fibrinogen levels. The search included PubMed-Medline, Scopus, ISI Web of Knowledge and Google Scholar databases (by June 2, 2017) and quality of studies was performed according to Cochrane criteria. Quantitative data synthesis was conducted using a random-effects model and sensitivity analysis by the leave-one-out method. Meta-regression analysis was performed to assess the modifiers of treatment response. Meta-analysis of data from 9 randomized placebo-controlled clinical trials with 2302 patients comprising 10 treatment arms did not suggest a significant change in plasma fibrinogen concentrations following metformin therapy (WMD: -0.25 g/L, 95% CI: -0.53, 0.04, p = 0.092). The effect size was robust in the leave-one-out sensitivity analysis and remained non-significant after omission of each single study from the meta-analysis. No significant effect of metformin on plasma fibrinogen concentrations was demonstrated in the current meta-analysis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Meta-analysis of candidate gene effects using bayesian parametric and non-parametric approaches.

    Science.gov (United States)

    Wu, Xiao-Lin; Gianola, Daniel; Rosa, Guilherme J M; Weigel, Kent A

    2014-01-01

    Candidate gene (CG) approaches provide a strategy for identification and characterization of major genes underlying complex phenotypes such as production traits and susceptibility to diseases, but the conclusions tend to be inconsistent across individual studies. Meta-analysis approaches can deal with these situations, e.g., by pooling effect-size estimates or combining P values from multiple studies. In this paper, we evaluated the performance of two types of statistical models, parametric and non-parametric, for meta-analysis of CG effects using simulated data. Both models estimated a "central" effect size while taking into account heterogeneity over individual studies. The empirical distribution of study-specific CG effects was multi-modal. The parametric model assumed a normal distribution for the study-specific CG effects whereas the non-parametric model relaxed this assumption by posing a more general distribution with a Dirichlet process prior (DPP). Results indicated that the meta-analysis approaches could reduce false positive or false negative rates by pooling strengths from multiple studies, as compared to individual studies. In addition, the non-parametric, DPP model captured the variation of the "data" better than its parametric counterpart.

  18. The association between COMT Val158Met polymorphism and migraine risk: A meta-analysis.

    Science.gov (United States)

    Liao, Yao-Jun; Jiang, Jing-Ru; Jin, San-Qing

    2017-05-01

    Background The COMT Val158Met polymorphism has long been regarded as a risk factor for migraine. The possible association between COMT Val158Met polymorphism and migraine has been evaluated in several studies, but the results are not consistent. Therefore, we conduct this meta-analysis to address these issues. Methods The WEB OF SCIENCE and EMBASE databases were searched for eligible studies. The odds ratio (OR) with the corresponding 95% confidence interval (CI) was calculated to estimate the strength of the association between COMT Val158Met polymorphism and migraine. Results Five studies with 979 cases and 1870 controls were ultimately included in the present meta-analysis. The overall data showed no significant association between COMT Val158Met polymorphism and migraine in the multiplicative model (OR = 0.97, 95% CI: 0.78-1.21, p = 0.805) and dominant model (OR = 1.05, 95% CI: 0.75-1.48, p = 0.773), neither in the additive model (OR = 0.97, 95% CI: 0.77-1.23, p = 0.817) nor in the recessive model (OR = 0.88, 95% CI: 0.71-1.09, p = 0.246). In subgroup analysis, both for Caucasian and Asian populations, no statistically significant associations were observed in any genetic models. Conclusions Our meta-analysis suggested that the COMT Val158Met polymorphism was not associated with migraine risk.

  19. Combining data and meta-analysis to build Bayesian networks for clinical decision support.

    Science.gov (United States)

    Yet, Barbaros; Perkins, Zane B; Rasmussen, Todd E; Tai, Nigel R M; Marsh, D William R

    2014-12-01

    Complex clinical decisions require the decision maker to evaluate multiple factors that may interact with each other. Many clinical studies, however, report 'univariate' relations between a single factor and outcome. Such univariate statistics are often insufficient to provide useful support for complex clinical decisions even when they are pooled using meta-analysis. More useful decision support could be provided by evidence-based models that take the interaction between factors into account. In this paper, we propose a method of integrating the univariate results of a meta-analysis with a clinical dataset and expert knowledge to construct multivariate Bayesian network (BN) models. The technique reduces the size of the dataset needed to learn the parameters of a model of a given complexity. Supplementing the data with the meta-analysis results avoids the need to either simplify the model - ignoring some complexities of the problem - or to gather more data. The method is illustrated by a clinical case study into the prediction of the viability of severely injured lower extremities. The case study illustrates the advantages of integrating combined evidence into BN development: the BN developed using our method outperformed four different data-driven structure learning methods, and a well-known scoring model (MESS) in this domain. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Asymptotic solutions for the case of SIE lens models and application to the quadruply imaged quasar Q2237+0305

    Science.gov (United States)

    Wertz, O.; Surdej, J.

    2014-07-01

    Considering a small misalignment between a point-like source, a singular isothermal ellipsoid deflector and an observer, we derive to first order simple relations between the model parameters and the lensed image positions, and an expression for the time delay between pairs of opposed images which is analogue to the one previously derived for the case of ɛ - γ models. Combined with the first-order astrometric relations, we retrieve a simple expression for the time delays, in agreement with Witt, Mao & Keeton, which solely depends on the lensed image positions. The real advantage of using the first-order equations when dealing with symmetric gravitational lens systems is to directly test the validity of the adopted lens model without having to perform any accurate numerical fit. In this paper, we present in detail the calculations which lead to those relations between the singular isothermal ellipsoid lens model parameters and the lensed image positions. In addition, we model the well-known Einstein cross Q2237+0305 with three families of models: ɛ - γ, singular isothermal ellipsoid and non-singular isothermal ellipsoid plus shear, using a genetic algorithm from the Qubist Optimization Toolbox. We conclude that although the non-singular isothermal ellipsoid plus shear model shows the best agreement between the calculated and the observed image positions ( = 0.0026 arcsec), the more simple singular isothermal ellipsoid also leads to quite satisfactory and acceptable results ( = 0.0059 arcsec).

  1. A meta-analysis of aneurysm formation in laser assisted vascular anastomosis (LAVA)

    Science.gov (United States)

    Chen, Chen; Peng, Fei; Xu, Dahai; Cheng, Qinghua

    2009-08-01

    Laser assisted vascular anastomosis (LAVA) is looked as a particularly promising non-suture method in future. However, aneurysm formation is one of the main reasons delay the clinical application of LAVA. Some scientists investigated the incidence of aneurysms in animal model. To systematically analyze the literature on reported incidence of aneurysm formation in LAVA therapy, we performed a meta-analysis comparing LAVA with conventional suture anastomosis (CSA) in animal model. Data were systematically retrieved and selected from PUBMED. In total, 23 studies were retrieved. 18 studies were excluded, and 5 studies involving 647 animals were included. Analysis suggested no statistically significant difference between LAVA and CSA (OR 1.24, 95%CI 0.66-2.32, P=0.51). Result of meta analysis shows that the technology of LAVA is very close to clinical application.

  2. A Technology-Organization-Environment Perspective on Eco-effectiveness: A Meta-analysis

    Directory of Open Access Journals (Sweden)

    Josephine LL Chong

    2017-03-01

    Full Text Available In this research, we perform a meta-analysis to explain how organizations are deploying technologies to enforce organizational sustainability by meeting the goal of eco-effectiveness. Prior studies have studied the influences on the adoption of technologies using the Technology-Organisation-Environment (TOE model that incorporate some aspects of technological, organizational or environmental factors. We collected prior research to test the factors of the TOE model to ascertain their relative impact and strength. Our meta-analysis found eight additional technological and organizational factors. We found strong support for IT infrastructure, perceived direct benefits, top management support, and competitive pressure. Moderate support for compatibility, technological readiness, perceived indirect benefits, knowledge (human resources, organizational size, attitudes towards innovation, learning culture, pressure from trade partners (industry characteristics and regulatory support. Lastly, weak support was found for relative advantage, complexity, perceived risks and information learning culture. Only two dimensions, financial resources and environmental uncertainty failed to reach statistical significance.

  3. An improved method for bivariate meta-analysis when within-study correlations are unknown.

    Science.gov (United States)

    Hong, Chuan; D Riley, Richard; Chen, Yong

    2018-03-01

    Multivariate meta-analysis, which jointly analyzes multiple and possibly correlated outcomes in a single analysis, is becoming increasingly popular in recent years. An attractive feature of the multivariate meta-analysis is its ability to account for the dependence between multiple estimates from the same study. However, standard inference procedures for multivariate meta-analysis require the knowledge of within-study correlations, which are usually unavailable. This limits standard inference approaches in practice. Riley et al proposed a working model and an overall synthesis correlation parameter to account for the marginal correlation between outcomes, where the only data needed are those required for a separate univariate random-effects meta-analysis. As within-study correlations are not required, the Riley method is applicable to a wide variety of evidence synthesis situations. However, the standard variance estimator of the Riley method is not entirely correct under many important settings. As a consequence, the coverage of a function of pooled estimates may not reach the nominal level even when the number of studies in the multivariate meta-analysis is large. In this paper, we improve the Riley method by proposing a robust variance estimator, which is asymptotically correct even when the model is misspecified (ie, when the likelihood function is incorrect). Simulation studies of a bivariate meta-analysis, in a variety of settings, show a function of pooled estimates has improved performance when using the proposed robust variance estimator. In terms of individual pooled estimates themselves, the standard variance estimator and robust variance estimator give similar results to the original method, with appropriate coverage. The proposed robust variance estimator performs well when the number of studies is relatively large. Therefore, we recommend the use of the robust method for meta-analyses with a relatively large number of studies (eg, m≥50). When the

  4. Viscous froth lens

    Science.gov (United States)

    Green, T. E.; Bramley, A.; Lue, L.; Grassia, P.

    2006-11-01

    Microscale models of foam structure traditionally incorporate a balance between bubble pressures and surface tension forces associated with curvature of bubble films. In particular, models for flowing foam microrheology have assumed this balance is maintained under the action of some externally imposed motion. Recently, however, a dynamic model for foam structure has been proposed, the viscous froth model, which balances the net effect of bubble pressures and surface tension to viscous dissipation forces: this permits the description of fast-flowing foam. This contribution examines the behavior of the viscous froth model when applied to a paradigm problem with a particularly simple geometry: namely, a two-dimensional bubble “lens.” The lens consists of a channel partly filled by a bubble (known as the “lens bubble”) which contacts one channel wall. An additional film (known as the “spanning film”) connects to this bubble spanning the distance from the opposite channel wall. This simple structure can be set in motion and deformed out of equilibrium by applying a pressure across the spanning film: a rich dynamical behavior results. Solutions for the lens structure steadily propagating along the channel can be computed by the viscous froth model. Perturbation solutions are obtained in the limit of a lens structure with weak applied pressures, while numerical solutions are available for higher pressures. These steadily propagating solutions suggest that small lenses move faster than large ones, while both small and large lens bubbles are quite resistant to deformation, at least for weak applied back pressures. As the applied back pressure grows, the structure with the small lens bubble remains relatively stiff, while that with the large lens bubble becomes much more compliant. However, with even further increases in the applied back pressure, a critical pressure appears to exist for which the steady-state structure loses stability and unsteady

  5. Objective lens

    Science.gov (United States)

    Olczak, Eugene G. (Inventor)

    2011-01-01

    An objective lens and a method for using same. The objective lens has a first end, a second end, and a plurality of optical elements. The optical elements are positioned between the first end and the second end and are at least substantially symmetric about a plane centered between the first end and the second end.

  6. LENS MODELS OF HERSCHEL-SELECTED GALAXIES FROM HIGH-RESOLUTION NEAR-IR OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Calanog, J. A.; Cooray, A.; Ma, B.; Casey, C. M. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Fu, Hai [Department of Physics and Astronomy, University of Iowa, Van Allen Hall, Iowa City, IA 52242 (United States); Wardlow, J. [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Amber, S. [Department of Physical Sciences, The Open University, Milton Keynes MK7 6AA (United Kingdom); Baker, A. J. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, NJ 08854 (United States); Baes, M. [1 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281, B-9000 Gent (Belgium); Bock, J. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Bourne, N.; Dye, S. [School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); Bussmann, R. S. [Department of Astronomy, Space Science Building, Cornell University, Ithaca, NY 14853-6801 (United States); Chapman, S. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Clements, D. L. [Astrophysics Group, Imperial College London, Blackett Laboratory, Prince Consort Road, London SW7 2AZ (United Kingdom); Conley, A. [Center for Astrophysics and Space Astronomy 389-UCB, University of Colorado, Boulder, CO 80309 (United States); Dannerbauer, H. [Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu-CNRS-Université Paris Diderot, CE-Saclay, pt courrier 131, F-91191 Gif-sur-Yvette (France); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo dell' Osservatorio 5, I-35122 Padova (Italy); Dunne, L.; Eales, S. [School of Physics and Astronomy, Cardiff University, Queens Buildings, The Parade, Cardiff CF24 3AA (United Kingdom); and others

    2014-12-20

    We present Keck-Adaptive Optics and Hubble Space Telescope high resolution near-infrared (IR) imaging for 500 μm bright candidate lensing systems identified by the Herschel Multi-tiered Extragalactic Survey and Herschel Astrophysical Terahertz Large Area Survey. Out of 87 candidates with near-IR imaging, 15 (∼17%) display clear near-IR lensing morphologies. We present near-IR lens models to reconstruct and recover basic rest-frame optical morphological properties of the background galaxies from 12 new systems. Sources with the largest near-IR magnification factors also tend to be the most compact, consistent with the size bias predicted from simulations and previous lensing models for submillimeter galaxies (SMGs). For four new sources that also have high-resolution submillimeter maps, we test for differential lensing between the stellar and dust components and find that the 880 μm magnification factor (μ{sub 880}) is ∼1.5 times higher than the near-IR magnification factor (μ{sub NIR}), on average. We also find that the stellar emission is ∼2 times more extended in size than dust. The rest-frame optical properties of our sample of Herschel-selected lensed SMGs are consistent with those of unlensed SMGs, which suggests that the two populations are similar.

  7. Consequences of bullying victimization in childhood and adolescence: A systematic review and meta-analysis

    OpenAIRE

    Moore, Sophie E; Norman, Rosana E; Suetani, Shuichi; Thomas, Hannah J; Sly, Peter D; Scott, James G

    2017-01-01

    AIM To identify health and psychosocial problems associated with bullying victimization and conduct a meta-analysis summarizing the causal evidence. METHODS A systematic review was conducted using PubMed, EMBASE, ERIC and PsycINFO electronic databases up to 28 February 2015. The study included published longitudinal and cross-sectional articles that examined health and psychosocial consequences of bullying victimization. All meta-analyses were based on quality-effects models. Evidence for cau...

  8. Household air pollution and cancers other than lung: a meta-analysis

    OpenAIRE

    Josyula, Sowmya; Lin, Juan; Xue, Xiaonan; Rothman, Nathaniel; Lan, Qing; Rohan, Thomas E; Hosgood, H Dean

    2015-01-01

    Household air pollution (HAP) from solid fuel combustion contributes to 2.6% of the global burden of disease. HAP emissions are an established lung carcinogen; however, associations with other cancer sites have not been fully explored. We conducted a meta-analysis of 18 case?control studies. Using fixed-effects models, utilizing the adjusted odds ratios (OR) and 95% confidence intervals (95% CI) from each study, we evaluated the association between HAP and cervical neoplasia (663 cases and 17...

  9. Reduction of the gravitational lens equation to a one-dimensional non-linear form for the tilted Plummer model family

    Science.gov (United States)

    Frutos-Alfaro, Francisco

    2007-03-01

    The gravitational lens equation for the tilted Plummer family of models can be reduced to a one-dimensional non-linear equation. For certain values of the slope of the radial profile it can be reduced to a polynomial form. Both forms are advantageous to find the roots, i.e. the images for a given model. The critical curve equations can also be reduced to a non-linear or polynomial form, and therefore it is useful to find the caustics. This lens model family has ample use in gravitational lens theory, and can produce up to five images.

  10. Stimulus Complexity and Categorical Effects in Human Auditory Cortex: An Activation Likelihood Estimation Meta-Analysis

    Science.gov (United States)

    Samson, Fabienne; Zeffiro, Thomas A.; Toussaint, Alain; Belin, Pascal

    2011-01-01

    Investigations of the functional organization of human auditory cortex typically examine responses to different sound categories. An alternative approach is to characterize sounds with respect to their amount of variation in the time and frequency domains (i.e., spectral and temporal complexity). Although the vast majority of published studies examine contrasts between discrete sound categories, an alternative complexity-based taxonomy can be evaluated through meta-analysis. In a quantitative meta-analysis of 58 auditory neuroimaging studies, we examined the evidence supporting current models of functional specialization for auditory processing using grouping criteria based on either categories or spectro-temporal complexity. Consistent with current models, analyses based on typical sound categories revealed hierarchical auditory organization and left-lateralized responses to speech sounds, with high speech sensitivity in the left anterior superior temporal cortex. Classification of contrasts based on spectro-temporal complexity, on the other hand, revealed a striking within-hemisphere dissociation in which caudo-lateral temporal regions in auditory cortex showed greater sensitivity to spectral changes, while anterior superior temporal cortical areas were more sensitive to temporal variation, consistent with recent findings in animal models. The meta-analysis thus suggests that spectro-temporal acoustic complexity represents a useful alternative taxonomy to investigate the functional organization of human auditory cortex. PMID:21833294

  11. The Effectiveness of Teamwork Training on Teamwork Behaviors and Team Performance: A Systematic Review and Meta-Analysis of Controlled Interventions

    OpenAIRE

    McEwan, Desmond; Ruissen, Geralyn R.; Eys, Mark A.; Zumbo, Bruno D.; Beauchamp, Mark R.

    2017-01-01

    The objective of this study was to conduct a systematic review and meta-analysis of teamwork interventions that were carried out with the purpose of improving teamwork and team performance, using controlled experimental designs. A literature search returned 16,849 unique articles. The meta-analysis was ultimately conducted on 51 articles, comprising 72 (k) unique interventions, 194 effect sizes, and 8439 participants, using a random effects model. Positive and significant medium-sized effects...

  12. Meta-analysis of gene expression microarrays with missing replicates

    Directory of Open Access Journals (Sweden)

    Leckie Christopher

    2011-03-01

    Full Text Available Abstract Background Many different microarray experiments are publicly available today. It is natural to ask whether different experiments for the same phenotypic conditions can be combined using meta-analysis, in order to increase the overall sample size. However, some genes are not measured in all experiments, hence they cannot be included or their statistical significance cannot be appropriately estimated in traditional meta-analysis. Nonetheless, these genes, which we refer to as incomplete genes, may also be informative and useful. Results We propose a meta-analysis framework, called "Incomplete Gene Meta-analysis", which can include incomplete genes by imputing the significance of missing replicates, and computing a meta-score for every gene across all datasets. We demonstrate that the incomplete genes are worthy of being included and our method is able to appropriately estimate their significance in two groups of experiments. We first apply the Incomplete Gene Meta-analysis and several comparable methods to five breast cancer datasets with an identical set of probes. We simulate incomplete genes by randomly removing a subset of probes from each dataset and demonstrate that our method consistently outperforms two other methods in terms of their false discovery rate. We also apply the methods to three gastric cancer datasets for the purpose of discriminating diffuse and intestinal subtypes. Conclusions Meta-analysis is an effective approach that identifies more robust sets of differentially expressed genes from multiple studies. The incomplete genes that mainly arise from the use of different platforms may also have statistical and biological importance but are ignored or are not appropriately involved by previous studies. Our Incomplete Gene Meta-analysis is able to incorporate the incomplete genes by estimating their significance. The results on both breast and gastric cancer datasets suggest that the highly ranked genes and associated GO

  13. Simulations of simple Bovine and Homo sapiens outer cortex ocular lens membrane models with a majority concentration of cholesterol.

    Science.gov (United States)

    Adams, Mark; Wang, Eric; Zhuang, Xiaohong; Klauda, Jeffery B

    2017-11-21

    The lipid composition of bovine and human ocular lens membranes has been probed, and a variety of lipids have been found including phosphatidylcholine (PC), phosphatidylethanolamine (PE), sphingomyelin (SM), and cholesterol (CHOL) with cholesterol being present in particularly high concentrations. In this study, we use the all-atom CHARMM36 force field to simulate binary, ternary, and quaternary mixtures as models of the ocular lens. High concentration of cholesterol, in combination with different and varying diversity of phospholipids (PL) and sphingolipids (SL), affect the structure of the ocular lens lipid bilayer. The following analyses were done for each simulation: surface area per lipid, component surface area per lipid, deuterium order parameters (S CD ), electron density profiles (EDP), membrane thickness, hydrogen bonding, radial distribution functions, clustering, and sterol tilt angle distribution. The S CD show significant bilayer alignment and packing in cholesterol-rich bilayers. The EDP show the transition from liquid crystalline to liquid ordered with the addition of cholesterol. Hydrogen bonds in our systems show the tendency for intramolecular interactions between cholesterol and fully saturated lipid tails for less complex bilayers. But with an increased number of components in the bilayer, the acyl chain of the lipids becomes a less important characteristic, and the headgroup of the lipid becomes more significant. Overall, cholesterol is the driving force of membrane structure of the ocular lens membrane where interactions between cholesterol, PL, and SL determine structure and function of the biomembrane. The goal of this work is to develop a baseline for further study of more physiologically realistic ocular lens lipid membranes. This article is part of a Special Issue entitled: Emergence of Complex Behavior in Biomembranes edited by Marjorie Longo. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Prognostic significance of IDH mutation in adult low-grade gliomas: a meta-analysis.

    Science.gov (United States)

    Sun, Hairui; Yin, Lianhu; Li, Showwei; Han, Song; Song, Guangrong; Liu, Ning; Yan, Changxiang

    2013-06-01

    Mutations in the gene encoding isocitrate dehydrogenase (IDH) have been identified in approximately 65-90 % of low-grade gliomas (LGGs). Various studies examining the relationship between IDH mutation with the clinical outcome in patients with LGGs have yielded inconclusive results. The purpose of the present meta-analysis of literature is to determine this effect. We conducted a meta-analysis of 10 studies (937 patients) that evaluated the correlation between IDH mutation and overall survival (OS). For the quantitative aggregation of the survival results, the IDH mutation effect was measured by hazard ratio (HR). Overall, the pooled HR was 0.585 (95 % CI, 0.376-0.911, p = 0.025, random effect model) for patients with IDH mutation vs patients without IDH mutation. IDH mutation was associated with better overall survival of LGGs. At least this trend was observed in our analysis.

  15. Effects of Peer-Led Interventions for Patients With Cancer: A Meta-Analysis

    Science.gov (United States)

    Lee, Myung Kyung; Suh, Soon-Rim

    2018-03-01

    To evaluate the effects of peer-led supportive interventions for patients with cancer.
. Six electronic databases (EMBASE, MEDLINE®, Google Scholar, Cochrane Library, ProQuest Medical Library, and CINAHL®) were searched for articles published from 1997 to May 2017.
. A total of 159 studies were identified. Eighteen (16 randomized, controlled trials [RCTs] and 2 non-RCTs) were eligible for systematic review and 16 for meta-analysis. The Cochrane risk of bias tool and Comprehensive Meta-Analysis software were used for analysis.
. The authors synthesized the results of the effect size of each trial according to cancer symptoms, coping, emotional health, quality of life, self-efficacy, sexuality, social support, and health-related behaviors. 
. The findings from this study suggest that an additional tiered evaluation that has a theoretical underpinning and high-quality methodology is required to confirm the efficacy of peer-led supportive interventions within cancer care models.

  16. Mass shootings: a meta-analysis of the dose-response relationship.

    Science.gov (United States)

    Wilson, Laura C

    2014-12-01

    A meta-analysis was conducted to examine the dose-response theory as it relates to posttraumatic stress symptoms (PTSSs) following mass shootings. It was hypothesized that greater exposure to a mass shooting would be associated with greater PTSSs. Trauma exposure in the current study was broadly defined as the extent to which a person experienced or learned about a mass shooting. The meta-analysis identified 11 qualifying studies that included 13 independent effect sizes from a total of 8,047 participants. The overall weighted mean effect size, based on a random effects model, was r = .19, p shooting on the relationship between exposure and PTSSs. Because so few studies satisfied the inclusion criteria, the present study also documents that this area of the literature is underresearched. Copyright © 2014 International Society for Traumatic Stress Studies.

  17. Relationship between hypothyroidism and the incidence of gestational diabetes: A meta-analysis.

    Science.gov (United States)

    Gong, Li-Li; Liu, He; Liu, Li-Hong

    2016-04-01

    Hypothyroidism disorders and gestational diabetes are among the most common endocrinopathies during pregnancy. We conducted a meta-analysis to investigate whether hypothyroidism in pregnancy is associated with gestational diabetes risk. Published literature from PubMed and EMBASE were searched for eligible publications. Pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a fixed- or random-effects model. Seven articles described the relationship between hypothyroidism and risk of gestational diabetes. This meta-analysis revealed that overt hypothyroidism was associated with an increased risk of gestational diabetes (OR 1.892, 95% CI 1.679-2.132, p hypothyroidism, with the OR of 1.558 (95% CI 1.292-1.877, p hypothyroidism was 1.749 (95% CI 1.586-1.928, p hypothyroidism may be a risk factor for gestational diabetes. Copyright © 2016. Published by Elsevier B.V.

  18. The Influence of Stereotype Threat on Immigrants: Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Markus eAppel

    2015-07-01

    Full Text Available In many regions around the world students with certain immigrant backgrounds underachieve in educational settings. This paper provides a review and meta-analysis on one potential source of the immigrant achievement gap: stereotype threat, a situational predicament that may prevent students to perform up to their full abilities. A meta-analysis of 19 experiments suggests an overall mean effect size of .63 (random effects model in support of stereotype threat theory. The results are complemented by moderator analyses with regard to circulation (published or unpublished research, cultural context (US vs. Europe, age of immigrants, type of stereotype threat manipulation, dependent measures, and means for identification of immigrant status; evidence on the role of ethnic identity strength is reviewed. Theoretical and practical implications of the findings are discussed.

  19. Lysergic acid diethylamide (LSD) for alcoholism: meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Krebs, Teri S; Johansen, Pål-Ørjan

    2012-07-01

    Assessments of lysergic acid diethylamide (LSD) in the treatment of alcoholism have not been based on quantitative meta-analysis. Hence, we performed a meta-analysis of randomized controlled trials in order to evaluate the clinical efficacy of LSD in the treatment of alcoholism. Two reviewers independently extracted the data, pooling the effects using odds ratios (ORs) by a generic inverse variance, random effects model. We identified six eligible trials, including 536 participants. There was evidence for a beneficial effect of LSD on alcohol misuse (OR, 1.96; 95% CI, 1.36-2.84; p = 0.0003). Between-trial heterogeneity for the treatment effects was negligible (I² = 0%). Secondary outcomes, risk of bias and limitations are discussed. A single dose of LSD, in the context of various alcoholism treatment programs, is associated with a decrease in alcohol misuse.

  20. The influence of stereotype threat on immigrants: review and meta-analysis

    Science.gov (United States)

    Appel, Markus; Weber, Silvana; Kronberger, Nicole

    2015-01-01

    In many regions around the world students with certain immigrant backgrounds underachieve in educational settings. This paper provides a review and meta-analysis on one potential source of the immigrant achievement gap: stereotype threat, a situational predicament that may prevent students to perform up to their full abilities. A meta-analysis of 19 experiments suggests an overall mean effect size of 0.63 (random effects model) in support of stereotype threat theory. The results are complemented by moderator analyses with regard to circulation (published or unpublished research), cultural context (US versus Europe), age of immigrants, type of stereotype threat manipulation, dependent measures, and means for identification of immigrant status; evidence on the role of ethnic identity strength is reviewed. Theoretical and practical implications of the findings are discussed. PMID:26217256

  1. Fluoroquinolone Sequential Therapy for Helicobacter pylori: A Meta-analysis.

    Science.gov (United States)

    Kale-Pradhan, Pramodini B; Mihaescu, Anela; Wilhelm, Sheila M

    2015-08-01

    As resistance of Helicobacter pylori to standard first-line therapy is increasing globally, alternative treatment regimens, such as a fluoroquinolone-based sequential regimen, have been explored. The objective of this meta-analysis was to compare the efficacy of fluoroquinolone-based sequential therapy with standard first-line treatment for H. pylori infection. Meta-analysis of six randomized controlled trials. A total of 738 H. pylori-infected, treatment-naive adults who received fluoroquinolone-based sequential therapy (5-7 days of a proton pump inhibitor [PPI] and amoxicillin therapy followed by 5-7 days of a PPI, a fluoroquinolone, and metronidazole or tinidazole or furazolidone therapy) and 733 H. pylori-infected, treatment-naive adults who received guideline-recommended, first-line therapy with standard triple therapy (7-14 days of a PPI plus amoxicillin and clarithromycin) or standard sequential therapy (5 days of a PPI plus amoxicillin, followed by an additional 5 days of triple therapy consisting of a PPI, clarithromycin, and metronidazole or tinidazole). A systematic literature search of the MEDLINE, PubMed, and Cochrane Central Register of Controlled Trials databases (from inception through January 2015) was conducted to identify randomized controlled trials that compared fluoroquinolone-based sequential therapy with guideline-recommended, first-line treatment regimens in H. pylori-infected, treatment-naive adults. All selected trials confirmed H. pylori infection prior to treatment as well as post-treatment eradication. A meta-analysis was performed by using Review Manager 5.2. Treatment effect was determined with a random-effects model by using the Mantel-Haenszel method and was reported as a risk ratio (RR) with 95% confidence interval (CI). In the six randomized controlled trials that met the inclusion criteria, 648 (87.8%) of 738 patients receiving fluoroquinolone-based sequential therapy and 521 (71.1%) of 733 patients receiving standard

  2. LENS MODEL AND TIME DELAY PREDICTIONS FOR THE SEXTUPLY LENSED QUASAR SDSS J2222+2745

    Energy Technology Data Exchange (ETDEWEB)

    Sharon, Keren; Johnson, Traci L.; Paterno-Mahler, Rachel [Department of Astronomy, University of Michigan, 1085 S. University Avenue, Ann Arbor, MI 48109 (United States); Bayliss, Matthew B. [Colby College, 5800 Mayflower Hill, Waterville, 04901, Maine (United States); Dahle, Håkon [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029, Blindern, NO-0315 Oslo (Norway); Florian, Michael K.; Gladders, Michael D. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Rigby, Jane R. [Astrophysics Science Division, Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Whitaker, Katherine E. [Department of Astronomy, University of Massachusetts-Amherst, Amherst, MA 01003 (United States); Wuyts, Eva, E-mail: kerens@umich.edu [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstr. 1, D-85741 Garching (Germany)

    2017-01-20

    SDSS J2222+2745 is a galaxy cluster at z = 0.49, strongly lensing a quasar at z = 2.805 into six widely separated images. In recent Hubble Space Telescope imaging of the field, we identify additional multiply lensed galaxies and confirm the sixth quasar image that was identified by Dahle et al. We used the Gemini-North telescope to measure a spectroscopic redshift of z = 4.56 of one of the lensed galaxies. These data are used to refine the lens model of SDSS J2222+2745, compute the time delay and magnifications of the lensed quasar images, and reconstruct the source image of the quasar host and a lensed galaxy at z = 2.3. This galaxy also appears in absorption in our Gemini spectra of the lensed quasar, at a projected distance of 34 kpc. Our model is in agreement with the recent time delay measurements of Dahle et al., who found τ {sub AB} = 47.7 ± 6.0 days and τ {sub AC} = −722 ± 24 days. We use the observed time delays to further constrain the model, and find that the model-predicted time delays of the three faint images of the quasar are τ {sub AD} = 502 ± 68 days, τ {sub AE} = 611 ± 75 days, and τ {sub AF} = 415 ± 72 days. We have initiated a follow-up campaign to measure these time delays with Gemini North. Finally, we present initial results from an X-ray monitoring program with Swift , indicating the presence of hard X-ray emission from the lensed quasar, as well as extended X-ray emission from the cluster itself, which is consistent with the lensing mass measurement and the cluster velocity dispersion.

  3. Smoking and placenta previa: a meta-analysis.

    Science.gov (United States)

    Shobeiri, Fatemeh; Jenabi, Ensiyeh

    2017-12-01

    Previous studies found a positive association between placenta previa and smoking during pregnancy. However, the results of these studies are inconsistent. The aim was to perform meta-analysis of the association between smoking during pregnancy and placenta previa. Major electronic databases, including PubMed, Web of Science, and Scopus were searched until June 2015. The heterogeneity across studies was explored by Q-test and I 2 statistic. The possibility of publication bias was assessed using Begg's and Egger's tests. The results were reported using odds ratio (OR) estimate with its 95% confidence intervals using a random-effects model. The literature search yielded 991 publications until October 2015 with 9,094,443 participants. Based on the random effect model, compared to nonsmoker women, the estimated OR and RR of placenta previa was 1.42 (95% CI: 1.30, 1.54) and 1.27 (95% CI: 1.18, 1.35), respectively. There is sufficient documents based on the observational studies that smoking during pregnancy is significantly associated with an increased risk of placenta previa. Therefore, smoking during pregnancy can be considered as a predictor of placenta previa.

  4. Toxoplasmosis and epilepsy--systematic review and meta analysis.

    Science.gov (United States)

    Ngoungou, Edgard B; Bhalla, Devender; Nzoghe, Amandine; Dardé, Marie-Laure; Preux, Pierre-Marie

    2015-02-01

    Toxoplasmosis is an important, widespread, parasitic infection caused by Toxoplasma gondii. The chronic infection in immunocompetent patients, usually considered as asymptomatic, is now suspected to be a risk factor for various neurological disorders, including epilepsy. We aimed to conduct a systematic review and meta-analysis of the available literature to estimate the risk of epilepsy due to toxoplasmosis. A systematic literature search was conducted of several databases and journals to identify studies published in English or French, without date restriction, which looked at toxoplasmosis (as exposure) and epilepsy (as disease) and met certain other inclusion criteria. The search was based on keywords and suitable combinations in English and French. Fixed and random effects models were used to determine odds ratios, and statistical significance was set at 5.0%. Six studies were identified, with an estimated total of 2888 subjects, of whom 1280 had epilepsy (477 positive for toxoplasmosis) and 1608 did not (503 positive for toxoplasmosis). The common odds ratio (calculated) by random effects model was 2.25 (95% CI 1.27-3.9), p = 0.005. Despite the limited number of studies, and a lack of high-quality data, toxoplasmosis should continue to be regarded as an epilepsy risk factor. More and better studies are needed to determine the real impact of this parasite on the occurrence of epilepsy.

  5. Indigeneity-Grounded Analysis (IGA as Policy(-Making Lens: New Zealand Models, Canadian Realities

    Directory of Open Access Journals (Sweden)

    Roger Maaka

    2010-05-01

    Full Text Available Engaging politically with the principles of indigeneity is neither an option nor a cop out. The emergence of Indigenous peoples as prime-time players on the world’s political stage attests to the timeliness and relevance of indigeneity in advancing a new postcolonial contract for living together differently. Insofar as the principles of indigeneity are inextricably linked with challenge, resistance, and transformation, this paper argues that reference to indigeneity as policy(- making paradigm is both necessary and overdue. To put this argument to the test, the politics of Maori indigeneity in Aotearoa New Zealand are analyzed and assessed in constructing an indigeneity agenda model. The political implications of an indigeneity-policy nexus are then applied to the realities of Canada’s Indigenous/Aboriginal peoples. The paper contends that, just as the Government is committed to a gender based analysis (GBA for improving policy outcomes along gender lines, so too should the principles of indigeneity (or aboriginality secure an indigeneity grounded analysis (IGA framework for minimizing systemic policy bias while maximizing Indigenous peoples inputs. The paper concludes by theorizing those provisional first principles that inform an IGA framework as a policy (-making lens.

  6. Metallothionein - immunohistochemical cancer biomarker: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jaromir Gumulec

    Full Text Available Metallothionein (MT has been extensively investigated as a molecular marker of various types of cancer. In spite of the fact that numerous reviews have been published in this field, no meta-analytical approach has been performed. Therefore, results of to-date immunohistochemistry-based studies were summarized using meta-analysis in this review. Web of science, PubMed, Embase and CENTRAL databases were searched (up to April 30, 2013 and the eligibility of individual studies and heterogeneity among the studies was assessed. Random and fixed effects model meta-analysis was employed depending on the heterogeneity, and publication bias was evaluated using funnel plots and Egger's tests. A total of 77 studies were included with 8,015 tissue samples (4,631 cases and 3,384 controls. A significantly positive association between MT staining and tumors (vs. healthy tissues was observed in head and neck (odds ratio, OR 9.95; 95% CI 5.82-17.03 and ovarian tumors (OR 7.83; 1.09-56.29, and a negative association was ascertained in liver tumors (OR 0.10; 0.03-0.30. No significant associations were identified in breast, colorectal, prostate, thyroid, stomach, bladder, kidney, gallbladder, and uterine cancers and in melanoma. While no associations were identified between MT and tumor staging, a positive association was identified with the tumor grade (OR 1.58; 1.08-2.30. In particular, strong associations were observed in breast, ovarian, uterine and prostate cancers. Borderline significant association of metastatic status and MT staining were determined (OR 1.59; 1.03-2.46, particularly in esophageal cancer. Additionally, a significant association between the patient prognosis and MT staining was also demonstrated (hazard ratio 2.04; 1.47-2.81. However, a high degree of inconsistence was observed in several tumor types, including colorectal, kidney and prostate cancer. Despite the ambiguity in some tumor types, conclusive results are provided in the tumors of

  7. Longevity of materials for pit and fissure sealing--results from a meta-analysis.

    Science.gov (United States)

    Kühnisch, Jan; Mansmann, Ulrich; Heinrich-Weltzien, Roswitha; Hickel, Reinhard

    2012-03-01

    This meta-analysis investigates the clinical retention of pit and fissure sealants in relation to observation time and material type. A search in the MEDLINE, EMBASE and CENTRAL databases identified 2944 abstracts (published prior to 9/30/2011), of which 485 clinical publications were analyzed in detail. A total of 146 articles included information about sealant retention, with a minimum observation time of 2 years. These publications were analyzed to determine the retention rates of the various materials studied (UV-light-, light- and auto-polymerizing resin-based sealants, fluoride-releasing materials, compomers, flowable composites and glass-ionomer-cement-based sealants). The meta-analysis used random effects models for longitudinal logistic regression and Bayesian statistics. As part of the systematic review, 98 clinical reports and 12 field trial reports were identified. Auto-polymerizing sealants had the longest observation time (up to 20 years) and were found to have a 5-year retention rate of 64.7% (95%CI=57.1-73.1%), which was estimated from the meta-analysis model. Resin-based light-polymerizing sealants and fluoride-releasing products showed similar 5-year retention rates (83.8%, 95%CI=54.9-94.7% and 69.9%, 95%CI=51.5-86.5%, respectively) for completely retained sealants. In contrast to these high retention rates, poor retention rates were documented for UV-light-polymerizing materials, compomers and glass-ionomer-cement-based sealants (5-year retention rates were materials, compomers and glass-ionomer-cement-based sealants were classified as inferior. The results of this meta-analysis suggested that resin-based sealants can be recommended for clinical use. The faster and less error-prone clinical application of light-polymerizing materials, however, makes them the preferred choice for daily dental practice. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. MR diffusion weighted imaging detecting cerebral infarction: a meta-analysis

    International Nuclear Information System (INIS)

    Yang Junle; Xu Min; Wang Peng; Zhang Qiujuan; Guo Youmin; Liu Min

    2008-01-01

    Objective: To determine the diagnostic value of diffusion-weighted imaging(DWI) in hyperacute and acute cerebral infarction by using Meta-analysis. Methods: Based on validity criteria for diagnostic research published by the Cochrane Methods Group on Screening and Diagnostic, studies in English and Chinese from 1997 to 2007 were selected from Medline, Cochrane, Springer, Ovid, Elsevier, LWW and CNKI( China National Knowledge Infrastructure). The characteristics of the included articles were appraised and extracted. Statistical analysis was performed with the software Meta-test 0.6 and Comprehensive meta-analysis 2.0. Heterogeneity of the included articles was tested, which was used to select proper effect model to calculate pooled weighted values of sensitivity and specificity and the corresponding 95% CI. Summary receiver operating characteristic (SROC) curve was performed and the area under the curve (Az) was calculated. Publication bias was analyzed by Funnel Plot in Comprehensive Meta- analysis 2.0. A sensitivity analysis was performed. Results: Twelve articles meeting inclusion criteria were analyzed for the value of DWI in hyperacute cerebral infarction. The pooled sensitivity, specificity and diagnostic odds ratio was 92%, 87%, 180.37 respectively, Az=0.9717. Novice is a main factor for total diagnostic effect (Q=4.34, P>0.05). Non-asymmetric funnel plot suggested the publication bias. Fifteen articles meeting inclusion criteria were analyzed for the value of DWI in both hyperacute and acute cerebral infarction (≤ 24 h). The pooled sensitivity, specificity diagnostic odds ratio was 92%, 91%, 623.62 respectively, Az=0.9659. Fixed effects model used in Meta-analysis for database suggested homogeneity (Q=2.70,P>0.05). Nonasymmetric funnel plot suggested the publication bias. Conclusions As a noninvasive method, diffusion-weighted imaging is valuable in detecting hyperacute and acute cerebral infarction. More support from multi-center prospective researches is

  9. Does Bruxism Contribute to Dental Implant Failure? A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Zhou, Yi; Gao, Jinxia; Luo, Le; Wang, Yining

    2016-04-01

    Bruxism was usually considered as a contraindication for oral implanting. The causal relationship between bruxism and dental implant failure was remained controversial in existing literatures. This meta-analysis was performed to investigate the relationship between them. This review conducted an electronic systematic literature search in MEDLINE (PubMed) and EmBase in November 2013 without time and language restrictions. Meanwhile, a hand searching for all the relevant references of included studies was also conducted. Study information extraction and methodological quality assessments were accomplished by two reviewers independently. A discussion ensued if any disagreement occurred, and unresolved issues were solved by consulting a third reviewer. Methodological quality was assessed by using the Newcastle-Ottawa Scale tool. Odds ratio (OR) with 95% confidence interval (CI) was pooled to estimate the relative effect of bruxism on dental implant failures. Fixed effects model was used initially; if the heterogeneity was high, random effects model was chosen for meta-analysis. Statistical analyses were carried out by using Review Manager 5.1. In this meta-analysis review, extracted data were classified into two groups based on different units. Units were based on the number of prostheses (group A) and the number of patients (group B). In group A, the total pooled OR of bruxers versus nonbruxers for all subgroups was 4.72 (95% CI: 2.66-8.36, p = .07). In group B, the total pooled OR of bruxers versus nonbruxers for all subgroups was 3.83 (95% CI: 2.12-6.94, p = .22). This meta-analysis was performed to evaluate the relationship between bruxism and dental implant failure. In contrast to nonbruxers, prostheses in bruxers had a higher failure rate. It suggests that bruxism is a contributing factor of causing the occurrence of dental implant technical/biological complications and plays a role in dental implant failure. © 2015 Wiley Periodicals, Inc.

  10. Risk Factors for Cement Leakage After Vertebroplasty or Kyphoplasty: A Meta-Analysis of Published Evidence.

    Science.gov (United States)

    Zhan, Yi; Jiang, Jianzhong; Liao, Haifen; Tan, Haitao; Yang, Keqin

    2017-05-01

    Cement leakage is the most common complication of vertebroplasty and kyphoplasty. So far, the reported risk factors remain conflicting because of limited data and lack of uniform measurement and evaluation. Here, we performed a systematic review and meta-analysis of potential risk factors for cement leakage after vertebroplasty or kyphoplasty. Relevant literature was retrieved using PubMed, EMBASE, Cochrane Controlled Trial Register, and MEDLINE with no language restriction, supplemented by a hand search of the reference lists of selected articles. A fixed-effects model was used if homogeneity existed among included studies; otherwise, a random-effects model was used. The results were presented with weighted mean difference for continuous outcomes and odds ratio (OR) for dichotomous outcomes with a 95% confidence interval (CI). Twenty-two studies consisting of 2872 patients with 4187 vertebrae were included in the meta-analysis. The incidences of cement leakage for percutaneous vertebroplasty and percutaneous balloon kyphoplasty were 54.7% and 18.4%, respectively. The significant risk factors for new vertebral compression fractures were intravertebral cleft (OR, 1.40; 95% CI, 1.09-1.78; P risk factors. The results of this meta-analysis suggest that patients with intravertebral cleft, cortical disruption, low cement viscosity, and high volume of injected cement may be at high risk for cement leakage after vertebroplasty or kyphoplasty. Rigorous patient selection and individual therapeutic strategy irrespective of age, sex and fracture type, operation level, and surgical approach may reduce the occurrence of cement leakage. Given the inherent limitation of the meta-analysis, more large sample-sized randomized controlled trials are needed to further validate the present findings. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Interaction between the FTO gene, body mass index and depression: meta-analysis of 13701 individuals.

    Science.gov (United States)

    Rivera, Margarita; Locke, Adam E; Corre, Tanguy; Czamara, Darina; Wolf, Christiane; Ching-Lopez, Ana; Milaneschi, Yuri; Kloiber, Stefan; Cohen-Woods, Sara; Rucker, James; Aitchison, Katherine J; Bergmann, Sven; Boomsma, Dorret I; Craddock, Nick; Gill, Michael; Holsboer, Florian; Hottenga, Jouke-Jan; Korszun, Ania; Kutalik, Zoltan; Lucae, Susanne; Maier, Wolfgang; Mors, Ole; Müller-Myhsok, Bertram; Owen, Michael J; Penninx, Brenda W J H; Preisig, Martin; Rice, John; Rietschel, Marcella; Tozzi, Federica; Uher, Rudolf; Vollenweider, Peter; Waeber, Gerard; Willemsen, Gonneke; Craig, Ian W; Farmer, Anne E; Lewis, Cathryn M; Breen, Gerome; McGuffin, Peter

    2017-08-01

    Background Depression and obesity are highly prevalent, and major impacts on public health frequently co-occur. Recently, we reported that having depression moderates the effect of the FTO gene, suggesting its implication in the association between depression and obesity. Aims To confirm these findings by investigating the FTO polymorphism rs9939609 in new cohorts, and subsequently in a meta-analysis. Method The sample consists of 6902 individuals with depression and 6799 controls from three replication cohorts and two original discovery cohorts. Linear regression models were performed to test for association between rs9939609 and body mass index (BMI), and for the interaction between rs9939609 and depression status for an effect on BMI. Fixed and random effects meta-analyses were performed using METASOFT. Results In the replication cohorts, we observed a significant interaction between FTO , BMI and depression with fixed effects meta-analysis (β = 0.12, P = 2.7 × 10 -4 ) and with the Han/Eskin random effects method ( P = 1.4 × 10 -7 ) but not with traditional random effects (β = 0.1, P = 0.35). When combined with the discovery cohorts, random effects meta-analysis also supports the interaction (β = 0.12, P = 0.027) being highly significant based on the Han/Eskin model ( P = 6.9 × 10 -8 ). On average, carriers of the risk allele who have depression have a 2.2% higher BMI for each risk allele, over and above the main effect of FTO Conclusions This meta-analysis provides additional support for a significant interaction between FTO , depression and BMI, indicating that depression increases the effect of FTO on BMI. The findings provide a useful starting point in understanding the biological mechanism involved in the association between obesity and depression. © The Royal College of Psychiatrists 2017.

  12. Copper in Diabetes Mellitus: a Meta-Analysis and Systematic Review of Plasma and Serum Studies.

    Science.gov (United States)

    Qiu, Qihong; Zhang, Fuping; Zhu, Wenjun; Wu, Juan; Liang, Min

    2017-05-01

    Copper (Cu) is an important trace element involved in oxidative stress, which is associated with the onset and progression of diabetes mellitus (DM). However, clinical studies comparing plasma or serum Cu levels in patients with DM and in healthy individuals report conflicting findings. Therefore, in this meta-analysis, we analyzed the circulating levels of Cu associated with DM (including type 1 diabetes mellitus [T1DM] and type 2 diabetes mellitus [T2DM]). We searched the articles indexed in PubMed, OVID, and Cochrane databases, published through January 2016 and meeting our predefined criteria. Requisite data were extracted, and a random-effect model or a fixed-effect model was used to conduct the meta-analysis. Fifteen eligible studies involving a total of 1079 DM patients and 561 healthy controls were identified. Overall, the DM patients showed higher Cu levels than the healthy controls (plasma Cu mean difference [MD] = 1.69 μmol/L, p diabetes also indicated higher levels of Cu in the plasma and serum of DM patients than in healthy controls, respectively. Stratification of DM patients associated with and without complications also revealed similar results. This meta-analysis suggests that DM patients carried higher levels of Cu than healthy individuals. However, international cohort studies are needed to corroborate our findings.

  13. Association of OPN rs11730582 polymorphism with cancer risk: a meta-analysis

    Directory of Open Access Journals (Sweden)

    He LL

    2016-03-01

    Full Text Available Lanlan He,1,* Yong Wang2,* 1Emergency Department, Zhenjiang First People’s Hospital, Zhenjiang, People’s Republic of China; 2Department of Interventional Radiology and Vascular Surgery, Zhongda Hospital, Southeast University, Nanjing, Jiangsu, People’s Republic of China *Both authors contributed equally to this work Purpose: Several molecular epidemiological studies have investigated the association between OPN rs11730582 C>T polymorphism and cancer risk, but the results are inconsistent. Hence, a meta-analysis was conducted to determine the association of this polymorphism with cancer risk. Materials and methods: The related articles were searched in PubMed, Embase, and Chinese National Knowledge Infrastructure databases. Pooled odds ratios and 95% confidence intervals were calculated to evaluate the strength of the associations. A random-effects model or fixed-effects model was employed depending on the heterogeneity. Results: A total of ten case-control studies involving 2,749 cancer cases and 3,398 controls were included in the meta-analysis. In overall analysis, OPN rs11730582 C>T polymorphism was not associated with cancer risk. In a stratified analysis by cancer type, no significant association was found between OPN rs11730582 C>T polymorphism and the risk of glioma, gastric cancer, and other cancers. Conclusion: This meta-analysis suggests that OPN rs11730582 C>T polymorphism is not associated with cancer susceptibility. Keywords: osteopontin, polymorphism, cancer, risk 

  14. Milk, yogurt, and lactose intake and ovarian cancer risk: a meta-analysis.

    Science.gov (United States)

    Liu, Jing; Tang, Wenru; Sang, Lei; Dai, Xiaoli; Wei, Danping; Luo, Ying; Zhang, Jihong

    2015-01-01

    Inconclusive information for the role of dairy food intake in relation to ovarian cancer risk may associate with adverse effects of lactose, which has been hypothesized to increase gonadotropin levels in animal models and ecological studies. Up to now, several studies have indicated the association between dairy food intake and risk of ovarian cancer, but no identified founding was reported. We performed this meta-analysis to derive a more precise estimation of the association between dairy food intake and ovarian cancer risk. Using the data from 19 available publications, we examined dairy food including low-fat/skim milk, whole milk, yogurt and lactose in relation to risk of ovarian cancer by meta-analysis. Pooled odds ratio (OR) with 95% confidence interval (CI) were used to assess the association. We observed a slightly increased risk of ovarian cancer with high intake of whole milk, but has no statistical significance (OR = 1.228, 95% CI = 1.031-1.464, P = 0.022). The results of other milk models did not provide evidence of positive association with ovarian cancer risk. This meta-analysis suggests that low-fat/skim milk, whole milk, yogurt and lactose intake has no associated with increased risk of ovarian cancer. Further studies with larger participants worldwide are needed to validate the association between dairy food intake and ovarian cancer.

  15. Dietary fiber intake reduces risk of inflammatory bowel disease: result from a meta-analysis.

    Science.gov (United States)

    Liu, Xiaoqin; Wu, Yili; Li, Fang; Zhang, Dongfeng

    2015-09-01

    Several epidemiological investigations have been conducted to evaluate the relationship between dietary fiber intake and inflammatory bowel diseases, but the results are inconsistent. This meta-analysis was performed to quantitatively summarize the evidence from observational studies. PubMed, Embase, and Web of Knowledge were searched for relevant articles published up to November 2014. The combined relative risks were calculated with the fixed- or random-effects model. Dose-response relationship was assessed using restricted cubic spline model. We hypothesized that the meta-analysis could yield a summary effect, which would indicate that dietary fiber intake could decrease the risk of ulcerative colitis and Crohn disease (CD). Overall, 8 articles involving 2 cohort studies, 1 nested case-control study, and 5 case-control studies were finally included in this study. The pooled relative risks with 95% confidence intervals of ulcerative colitis and CD for the highest vs lowest categories of dietary fiber intake were 0.80 (0.64-1.00) and 0.44 (0.29-0.69), respectively. A linear dose-response relationship was found between dietary fiber and CD risk, and the risk of CD decreased by 13% (P fiber intake. The results from this meta-analysis indicated that the intake of dietary fiber was significantly associated with a decreased risk of inflammatory bowel disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Is gestational diabetes mellitus an independent risk factor for macrosomia: a meta-analysis?

    Science.gov (United States)

    He, Xiu-Jie; Qin, Feng-Yun; Hu, Chuan-Lai; Zhu, Meng; Tian, Chao-Qing; Li, Li

    2015-04-01

    The aim of our meta-analysis was to explore whether gestational diabetes mellitus (GDM) is an independent risk factor for macrosomia or not. Three databases were systematically reviewed and reference lists of relevant articles were checked. Meta-analysis of published epidemiological studies (cohort and case-control studies) comparing whether GDM was associated with macrosomia. Calculations of pooled estimates were conducted in random-effect models. Heterogeneity was tested by using Chi square test and I (2) statistics. Publication bias was estimated from Egger's test (linear regression method) and Begg's test (rank correlation method). Twelve studies met the inclusion criteria, including five cohort studies and seven case-control studies. The meta-analysis showed that GDM was associated with macrosomia independent of other risk factors. The adjusted odds ratio was 1.71, 95% CI (1.52, 1.94) in random-effect model, stratified analyses showed no differences regarding different study design, quality grade, definition of macrosomia, location of study and number of confounding factors adjusted for. There was no indication of a publication bias either from the result of Egger's test or Begg's test. Our findings indicate that GDM should be considered as an independent risk factor for newborn macrosomia. To adequately evaluate the clinical evolution of GDM need to be carefully assessed and monitored.

  17. Maternal pre-pregnancy obesity and the risk of macrosomia: a meta-analysis.

    Science.gov (United States)

    Dai, Rui-Xue; He, Xiu-Jie; Hu, Chuan-Lai

    2018-01-01

    The aim of our meta-analysis was to explore whether pre-pregnancy obesity is regarded as an important risk factor for predicting macrosomia or not. Three databases were systematically reviewed and reference lists of relevant articles were checked. Meta-analysis of published cohort studies comparing whether pre-pregnancy obesity was associated with macrosomia and adjusting for potential confounding factors. Calculations of pooled estimates were conducted in random-effect model. Heterogeneity was tested by using Chi-square test and I 2 statistics. Publication bias was estimated from Egger's test (linear regression method) and Begg's test (rank correlation method). Sixteen cohort studies met the inclusion criteria. The meta-analysis showed that pre-pregnancy obesity was associated with macrosomia as an important risk factor. The adjusted odds ratio was 1.93, 95% CI (1.65, 2.27) in random-effect model, stratified analyses showed no differences regarding different quality grade, definition of macrosomia, location of study and number of confounding factors adjusted for. There was no indication of a publication bias either from the result of Egger's test or Begg's test. Our findings indicated that pre-pregnancy obesity should be considered as an important risk factor for macrosomia. The effect of pre-pregnancy obesity on macrosomia need to be carefully assessed and monitored.

  18. Meta-analysis without study-specific variance information: Heterogeneity case.

    Science.gov (United States)

    Sangnawakij, Patarawan; Böhning, Dankmar; Niwitpong, Sa-Aat; Adams, Stephen; Stanton, Michael; Holling, Heinz

    2017-01-01

    The random effects model in meta-analysis is a standard statistical tool often used to analyze the effect sizes of the quantity of interest if there is heterogeneity between studies. In the special case considered here, meta-analytic data contain only the sample means in two treatment arms and the sample sizes, but no sample standard deviation. The statistical comparison between two arms for this case is not possible within the existing meta-analytic inference framework. Therefore, the main objective of this paper is to estimate the overall mean difference and associated variances, the between-study variance and the within-study variance, as specified as the important elements in the random effects model. These estimators are obtained using maximum likelihood estimation. The standard errors of the estimators and a quantification of the degree of heterogeneity are also investigated. A measure of heterogeneity is suggested which adjusts the original suggested measure of Higgins' I 2 for within study sample size. The performance of the proposed estimators is evaluated using simulations. It can be concluded that all estimated means converged to their associated true parameter values, and its standard errors tended to be small if the number of the studies involved in the meta-analysis was large. The proposed estimators could be favorably applied in a meta-analysis on comparing two surgeries for asymptomatic congenital lung malformations in young children.

  19. A re-evaluation of random-effects meta-analysis.

    Science.gov (United States)

    Higgins, Julian P T; Thompson, Simon G; Spiegelhalter, David J

    2009-01-01

    Meta-analysis in the presence of unexplained heterogeneity is frequently undertaken by using a random-effects model, in which the effects underlying different studies are assumed to be drawn from a normal distribution. Here we discuss the justification and interpretation of such models, by addressing in turn the aims of estimation, prediction and hypothesis testing. A particular issue that we consider is the distinction between inference on the mean of the random-effects distribution and inference on the whole distribution. We suggest that random-effects meta-analyses as currently conducted often fail to provide the key results, and we investigate the extent to which distribution-free, classical and Bayesian approaches can provide satisfactory methods. We conclude that the Bayesian approach has the advantage of naturally allowing for full uncertainty, especially for prediction. However, it is not without problems, including computational intensity and sensitivity to a priori judgements. We propose a simple prediction interval for classical meta-analysis and offer extensions to standard practice of Bayesian meta-analysis, making use of an example of studies of 'set shifting' ability in people with eating disorders.

  20. MRI diagnosis in meniscal tears: a Meta analysis

    International Nuclear Information System (INIS)

    Liu Xiaosheng; Xu Jianrong; Hua Jia; Wang Baisong

    2007-01-01

    Objective: To perform a Meta-analysis to evaluate the overall diagnostic value of magnetic resonance imaging (MRI) in patients with suspected meniscal tears. Methods: All the papers concerning the diagnosis of meniscal tears using MRI in both English and Chinese published from 1998 to 2004 had been searched and reviewed, and the studies with the arthroscopy as the gold standard were adopted as eligible. Statistical analysis was performed employing SAS 8.0. Heterogeneity of the included articles was tested, which was used to select proper effect model to calculate pooled weighted sensitivity, specificity and accuracy. Summary receiver operating characteristic (SROC) analyses were performed for tears of both menisci. Finally, subgroup analysis on magnetic field strength was performed. Results: Totally 11 studies were met the inclusion criteria with a total of 1221 patients. The pooled indexes of diagnostic performance and SROC demonstrated a high discriminatory power for detecting tears of the medial and lateral menisci. The value of TPR * for medial and lateral menisci showed no significant difference (0.90, 0.86, respectively, Z=0.11, P>0.05). Subgroup analysis demonstrated no statistically significant difference on diagnostic performance for various magnetic field strength (P>0.05). Conclusion: MRI is a highly accurate diagnostic tool for detecting tears of the medial and lateral menisci. At present, there is no evidence to ascertain that higher magnetic field strength improves discriminatory power for meniscal tears. (authors)

  1. Bayesian multivariate meta-analysis of multiple factors.

    Science.gov (United States)

    Lin, Lifeng; Chu, Haitao

    2018-02-09

    In medical sciences, a disease condition is typically associated with multiple risk and protective factors. Although many studies report results of multiple factors, nearly all meta-analyses separately synthesize the association between each factor and the disease condition of interest. The collected studies usually report different subsets of factors, and the results from separate analyses on multiple factors may not be comparable because each analysis may use different subpopulation. This may impact on selecting most important factors to design a multifactor intervention program. This article proposes a new concept, multivariate meta-analysis of multiple factors (MVMA-MF), to synthesize all available factors simultaneously. By borrowing information across factors, MVMA-MF can improve statistical efficiency and reduce biases compared with separate analyses when factors were missing not at random. As within-study correlations between factors are commonly unavailable from published articles, we use a Bayesian hybrid model to perform MVMA-MF, which effectively accounts for both within- and between-study correlations. The performance of MVMA-MF and the conventional methods are compared using simulations and an application to a pterygium dataset consisting of 29 studies on 8 risk factors. Copyright © 2018 John Wiley & Sons, Ltd.

  2. Affective mapping: An activation likelihood estimation (ALE) meta-analysis.

    Science.gov (United States)

    Kirby, Lauren A J; Robinson, Jennifer L

    2017-11-01

    Functional neuroimaging has the spatial resolution to explain the neural basis of emotions. Activation likelihood estimation (ALE), as opposed to traditional qualitative meta-analysis, quantifies convergence of activation across studies within affective categories. Others have used ALE to investigate a broad range of emotions, but without the convenience of the BrainMap database. We used the BrainMap database and analysis resources to run separate meta-analyses on coordinates reported for anger, anxiety, disgust, fear, happiness, humor, and sadness. Resultant ALE maps were compared to determine areas of convergence between emotions, as well as to identify affect-specific networks. Five out of the seven emotions demonstrated consistent activation within the amygdala, whereas all emotions consistently activated the right inferior frontal gyrus, which has been implicated as an integration hub for affective and cognitive processes. These data provide the framework for models of affect-specific networks, as well as emotional processing hubs, which can be used for future studies of functional or effective connectivity. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. The Association Between Anxiety and Falls: A Meta-Analysis.

    Science.gov (United States)

    Hallford, David John; Nicholson, Geoff; Sanders, Kerrie; McCabe, Marita P

    2017-09-01

    Falls occur frequently among older adults and can lead to a range of adverse and debilitating outcomes. Although symptoms of clinical anxiety have been implicated as risk factors for falls, there is no current consensus on the empirical association between anxiety and falls. The current study aimed to address this gap in the literature by conducting a quantitative, meta-analytic review of findings from previous studies. A systematic literature search of bibliographic databases was conducted, yielding 18 studies that fit the criteria for inclusion in the meta-analysis. A random-effects model of all 18 studies showed a significant overall odds ratio of 1.53 (95% CI 1.28-1.83, p anxiety were associated with a 53% increased likelihood of falls. A high amount of variance among effect sizes was observed. Only age was identified as a moderator of this relationship in a subgroup of the samples. Clinical anxiety is associated with falls, however, further research is required to elucidate the factors that might moderate or mediate this relationship, the casual pathways through which they are related, and the associations between different types of anxiety and falls. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Affective empathy in schizophrenia: a meta-analysis.

    Science.gov (United States)

    Bonfils, Kelsey A; Lysaker, Paul H; Minor, Kyle S; Salyers, Michelle P

    2016-08-01

    Affective empathy, or the emotional response one has to the experiences or emotional states of others, contributes to relationship-maintaining behaviors and is key in fostering social connections, yet no work has synthesized the body of literature for people with schizophrenia. The aim of the present meta-analysis was to determine the extent to which those diagnosed with schizophrenia experience deficits in affective empathy. A literature search was conducted of studies examining empathy. Data were analyzed using a random effects meta-analytic model with Hedges' g standardized mean difference effect size. Individuals with schizophrenia exhibited significant, medium deficits in affective empathy (k=37). Measurement type moderated the affective empathy deficit such that performance-based measures showed larger schizophrenia group deficits than self-report measures. Consistent, significant deficits in affective empathy were found comparing people with schizophrenia to healthy controls, especially when using performance-based assessments. The medium effect suggests an important role for empathy in the realm of social cognitive research, and points to the need for further investigation of measurement techniques and associations with functional outcomes. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Association between tea consumption and osteoporosis: A meta-analysis.

    Science.gov (United States)

    Sun, Kang; Wang, Le; Ma, Qingping; Cui, Qiaoyun; Lv, Qianru; Zhang, Wenzheng; Li, Xinghui

    2017-12-01

    Previous reports have suggested a potential association of tea consumption with the risk of osteoporosis. As such association is controversial, we conducted a meta-analysis to assess the relationship between tea consumption and osteoporosis. We systematically searched PubMed, EMBASE and WanFang databases until March 30, 2016, using the keywords "tea and osteoporosis," without limits of language. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were derived by using random-effects models throughout the analyses. We conducted the analysis of the statistical heterogeneity using Cochrane I. The funnel plot was used to speculate the publication bias, while the subgroup analysis and multiround elimination method were employed. Our study was based on 17 journal articles, including 2 prospective cohort studies, 4 case-control studies, and 11 cross-sectional studies. In the present study, the total OR of osteoporosis for the highest versus the lowest categories of tea consumption was 0.62 (95% CI, 0.46-0.83), with significant heterogeneity among studies (I = 94%, P tea consumption and osteoporosis. Subgroup analysis showed that tea consumption could reduce the risk of osteoporosis in all examined subgroups. In the present study, it can be concluded from the results that tea consumption can reduce the risk of osteoporosis.

  6. A meta-analysis of executive components of working memory.

    Science.gov (United States)

    Nee, Derek Evan; Brown, Joshua W; Askren, Mary K; Berman, Marc G; Demiralp, Emre; Krawitz, Adam; Jonides, John

    2013-02-01

    Working memory (WM) enables the online maintenance and manipulation of information and is central to intelligent cognitive functioning. Much research has investigated executive processes of WM in order to understand the operations that make WM "work." However, there is yet little consensus regarding how executive processes of WM are organized. Here, we used quantitative meta-analysis to summarize data from 36 experiments that examined executive processes of WM. Experiments were categorized into 4 component functions central to WM: protecting WM from external distraction (distractor resistance), preventing irrelevant memories from intruding into WM (intrusion resistance), shifting attention within WM (shifting), and updating the contents of WM (updating). Data were also sorted by content (verbal, spatial, object). Meta-analytic results suggested that rather than dissociating into distinct functions, 2 separate frontal regions were recruited across diverse executive demands. One region was located dorsally in the caudal superior frontal sulcus and was especially sensitive to spatial content. The other was located laterally in the midlateral prefrontal cortex and showed sensitivity to nonspatial content. We propose that dorsal-"where"/ventral-"what" frameworks that have been applied to WM maintenance also apply to executive processes of WM. Hence, WM can largely be simplified to a dual selection model.

  7. Meta-Analysis of the Prevalence of Unacknowledged Rape.

    Science.gov (United States)

    Wilson, Laura C; Miller, Katherine E

    2016-04-01

    Many sexual violence survivors do not label their experiences as rape but instead use more benign labels, such as "bad sex" or "miscommunication." A meta-analysis was conducted to estimate the mean prevalence of unacknowledged rape and to inform our understanding of methodological factors that influence the detection of this phenomenon. Studies were identified using PsycINFO, PubMED, and PILOTS and were required to report the percentage of unacknowledged rape that had occurred since the age of 14 among female survivors. Moderator variables included mean participant age, recruitment source, rape definition, and unacknowledged rape definition. Twenty-eight studies (30 independent samples) containing 5,917 female rape survivors met the inclusion criteria. Based on a random effects model, the overall weighted mean percentage of unacknowledged rape was 60.4% (95% confidence interval [55.0%, 65.6%]). There was a large amount of heterogeneity, Q(29) = 445.11, p rape survivors do not acknowledge that they have been raped. The results suggest that screening tools should use behaviorally descriptive items about sexual contact, rather than using terms such as "rape." © The Author(s) 2015.

  8. Effect of Probiotics on Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

    Science.gov (United States)

    Huang, Ruixue; Wang, Ke; Hu, Jianan

    2016-08-06

    It has been reported that gut probiotics play a major role in the bidirectional communication between the gut and the brain. Probiotics may be essential to people with depression, which remains a global health challenge, as depression is a metabolic brain disorder. However, the efficacy of probiotics for depression is controversial. This study aimed to systematically review the existing evidence on the effect of probiotics-based interventions on depression. Randomized, controlled trials, identified through screening multiple databases and grey literature, were included in the meta-analysis. The meta-analysis was performed using Review Manager 5.3 software using a fixed-effects model. The meta-analysis showed that probiotics significantly decreased the depression scale score (MD (depressive disorder) = -0.30, 95% CI (-0.51--0.09), p = 0.005) in the subjects. Probiotics had an effect on both the healthy population (MD = -0.25, 95% CI (-0.47--0.03), p = 0.03) and patients with major depressive disorder (MDD) (MD = -0.73, 95% CI (-1.37--0.09), p = 0.03). Probiotics had an effect on the population aged under 60 (MD = -0.43, 95% CI (-0.72--0.13), p = 0.005), while it had no effect on people aged over 65 (MD = -0.18, 95% CI (-0.47-0.11), p = 0.22). This is the first systematic review and meta-analysis with the goal of determining the effect of probiotics on depression. We found that probiotics were associated with a significant reduction in depression, underscoring the need for additional research on this potential preventive strategy for depression.

  9. Antibiotics for the treatment of leptospirosis: Systematic review and meta-analysis of controlled trials

    Directory of Open Access Journals (Sweden)

    Jaykaran Charan

    2013-01-01

    Full Text Available Leptospirosis is a zoonotic disease prevalent mainly in developing countries and is associated with high case fatality. Antibiotics especially penicillin are the mainstay of treatment for a suspected or confirm case of leptospirosis but role of Penicillin has not been evaluated systematically in the light of current evidence. The present systematic review and meta-analysis is done to evaluate the role of antibiotics in the treatment of leptospirosis. Parallel group clinical trials involving use of penicillin in treatment of leptospirosis were searched from all available sources. Ten clinical trials were found suitable as per laid inclusion criteria eligible for present systematic review and five clinical trials were included in meta-analysis. Clinical trials included for meta-analysis were compared on the basis of mortality, fever days, numbers of patients presenting with oliguria, and number of patients undergoing need-based dialysis. Analysis was done by comprehensive meta-analysis software 2. Qualitative outcomes are summarized as odds ratio and quantitative outcomes are summarized as standard mean difference with 95% confidence interval. Random and fixed models are used for analysis. There was no significant difference between penicillin group and controlled group for mortality (Odds ratio 1.59 (95% CI 0.59-4.29, P = 0.35, fever days (std difference in mean = −0.223 (95% CI 0.394-0.995, P = 0.358, number of patients presenting with oliguria (Odds ratio 1.795 (95% CI 0.325-9.929, P = 0.502, and number of patients who underwent need based dialysis (Odds ratio 1.587 (95% CI 0.919-2.731, P = 0.098. Role of various antibiotics in treatment of leptospirosis is uncertain, and can be attributed to nonavailability of adequate clinical trials. Role of penicillin in the treatment of leptospirosis can be debated.

  10. Effect of Grape Polyphenols on Blood Pressure: A Meta-Analysis of Randomized Controlled Trials.

    Directory of Open Access Journals (Sweden)

    Shao-Hua Li

    Full Text Available The effect of grape polyphenols on blood pressure remains unclear, which we aimed to address via a meta-analysis study.We conducted study trial searches in PubMed, Embase, and the Cochrane Library databases. Summary estimates of weighted mean differences and 95% confidence intervals were obtained by using fixed-effects models. Subgroup analyses were performed to identify the source of heterogeneity. The protocol details of our meta-analysis have been submitted to the international database of prospectively registered systematic reviews (registration number CRD42015019196.Ten studies were included in the present meta-analysis. Our results showed daily grape polyphenol intake could significantly reduce systolic blood pressure by 1.48 mmHg when compared to control subjects (12 comparisons; -1.48 [-2.79 to -0.16] mmHg; P = 0.03. Subgroup analyses indicated larger reduction was identified in the intake of low-dose of grape polyphenols (< 733 mg/day, median level of the included studies or patients with metabolic syndrome. Contrarily, diastolic blood pressure was not significantly decreased in the grape polyphenols group as compared to controls. No significant heterogeneity or publication bias was detected in the meta-analysis of either systolic or diastolic blood pressure.Daily grape polyphenol intake can significantly reduce the systolic blood pressure in humans, although the reduction is modest when compared with anti-hypertensive medications. Larger, better designed trials, that specifically include hypertensive subjects, are required to verify our results in the future.

  11. Alcohol Intake and Risk of Thyroid Cancer: A Meta-Analysis of Observational Studies.

    Science.gov (United States)

    Hong, Seung-Hee; Myung, Seung-Kwon; Kim, Hyeon Suk

    2017-04-01

    The purpose of this study was to assess whether alcohol intake is associated with the risk of thyroid cancer by a meta-analysis of observational studies. We searched PubMed and EMBASE in June of 2015 to locate eligible studies. We included observational studies such as cross-sectional studies, case-control studies, and cohort studies reporting odd ratios (ORs) or relative risk (RRs) with 95% confidence intervals (CIs). We included 33 observational studies with two cross-sectional studies, 20 case-controls studies, and 11 cohort studies, which involved a total of 7,725 thyroid cancer patients and 3,113,679 participants without thyroid cancer in the final analysis. In the fixed-effect model meta-analysis of all 33 studies, we found that alcohol intake was consistently associated with a decreased risk of thyroid cancer (OR or RR, 0.74; 95% CI, 0.67 to 0.83; I 2 =38.6%). In the subgroup meta-analysis by type of study, alcohol intake also decreased the risk of thyroid cancer in both case-control studies (OR, 0.77; 95% CI, 0.65 to 0.92; I 2 =29.5%; n=20) and cohort studies (RR, 0.70; 95% CI, 0.60 to 0.82; I 2 =0%; n=11). Moreover, subgroup meta-analyses by type of thyroid cancer, gender, amount of alcohol consumed, and methodological quality of study showed that alcohol intake was significantly associated with a decreased risk of thyroid cancer. The current meta-analysis of observational studies found that, unlike most of other types of cancer, alcohol intake decreased the risk of thyroid cancer.

  12. Association between polypharmacy and death: A systematic review and meta-analysis.

    Science.gov (United States)

    Leelakanok, Nattawut; Holcombe, Andrea L; Lund, Brian C; Gu, Xiaomei; Schweizer, Marin L

    Polypharmacy has been linked to a myriad of adverse consequences, and escalating rates of polypharmacy present an emerging concern, particularly among older adults. This systematic review and meta-analysis summarizes the existing literature concerning the association between polypharmacy and mortality. A systematic literature review was done by searching the EMBASE, PubMed, Scopus, and International Pharmaceutical Abstract databases to identify studies assessing the association between polypharmacy and death published until June 2016. Studies that investigated the association between polypharmacy and mortality were eligible for this systematic review and meta-analysis. Data were extracted by the first and second authors independently using a data extraction form. Disagreement was resolved by consensus. A meta-analysis was performed using random effect models. Heterogeneity was assessed using the I 2 statistic. Forty-seven studies were included in this meta-analysis. The underlying populations were heterogeneous (I 2 = 91.5%). When defined as a discrete variable, pooled risk estimates demonstrated a significant association between polypharmacy and death (pooled-adjusted odds ratio [aOR] 1.08 [95% CI 1.04-1.12]). When defined categorically, a dose-response relationship was observed across escalating thresholds for defining polypharmacy. Categorical thresholds for polypharmacy using values of 1-4 medications, 5 medications, and 6-9 medications were significantly associated with death (P discrete and categorical definitions. The causality of this relationship remains unclear, but it emphasizes the need for approaches to health care delivery that achieve an optimal balance of risk and benefit in medication prescribing. Copyright © 2017 American Pharmacists Association®. All rights reserved.

  13. Robotic versus laparoscopic distal pancreatectomy: an up-to-date meta-analysis.

    Science.gov (United States)

    Guerrini, Gian Piero; Lauretta, Andrea; Belluco, Claudio; Olivieri, Matteo; Forlin, Marco; Basso, Stefania; Breda, Bruno; Bertola, Giulio; Di Benedetto, Fabrizio

    2017-11-09

    Laparoscopic distal pancreatectomy (LDP) reduces postoperative morbidity, hospital stay and recovery as compared with open distal pancreatectomy. Many authors believe that robotic surgery can overcome the difficulties and technical limits of LDP thanks to improved surgical manipulation and better visualization. Few studies in the literature have compared the two methods in terms of surgical and oncological outcome. The aim of this study was to compare the results of robotic (RDP) and laparoscopic distal pancreatectomy. A systematic review and meta-analysis was conducted of control studies published up to December 2016 comparing LDP and RDP. Two Reviewers independently assessed the eligibility and quality of the studies. The meta-analysis was conducted using either the fixed-effect or the random-effect model. Ten studies describing 813 patients met the inclusion criteria. This meta-analysis shows that the RDP group had a significantly higher rate of spleen preservation [OR 2.89 (95% confidence interval 1.78-4.71, p < 0.0001], a lower rate of conversion to open OR 0.33 (95% CI 0.12-0.92), p = 0.003] and a shorter hospital stay [MD -0.74; (95% CI -1.34 -0.15), p = 0.01] but a higher cost than the LDP group, while other surgical outcomes did not differ between the two groups. This meta-analysis suggests that the RDP procedure is safe and comparable in terms of surgical results to LDP. However, even if the RDP has a higher cost compared to LDP, it increases the rate of spleen preservation, reduces the risk of conversion to open surgery and is associated to shorter length of hospital stay.

  14. Constipation preceding Parkinson's disease: a systematic review and meta-analysis.

    Science.gov (United States)

    Adams-Carr, Kerala L; Bestwick, Jonathan P; Shribman, Samuel; Lees, Andrew; Schrag, Anette; Noyce, Alastair J

    2016-07-01

    To systematically review published literature to estimate the magnitude of association between premorbid constipation and later diagnosis of Parkinson's disease. Constipation is a recognised non-motor feature of Parkinson's and has been reported to predate diagnosis in a number of observational studies. A systematic review and meta-analysis was carried out following the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) criteria. A literature search was undertaken in December 2014 using PubMed and the search terms 'Parkinson's disease' and 'constipation'. Articles were screened for suitability and reviewed against inclusion and exclusion criteria. Studies were included if they assessed constipation by means of a structured questionnaire or if constipation/drugs used to treat constipation were coded in patient medical records. Data were extracted using a standardised template and effect size estimates combined using a fixed-effects model. Heterogeneity was explored with the I(2) statistic. 9 studies were included in the meta-analysis, with a combined sample size of 741 593 participants. Those with constipation had a pooled OR of 2.27 (95% CI 2.09 to 2.46) for developing subsequent Parkinson's disease compared with those without constipation. Weak evidence for heterogeneity was found (I(2)=18.9%, p=0.282). Restricting analysis to studies assessing constipation more than 10 years prior to Parkinson's disease gave a pooled OR of 2.13 (95% CI 1.78 to 2.56; I(2)=0.0%). This systematic review and meta-analysis demonstrates that people with constipation are at a higher risk of developing Parkinson's disease compared with those without and that constipation can predate Parkinson's diagnosis by over a decade. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  15. Influence of oral processing on appetite and food intake - A systematic review and meta-analysis.

    Science.gov (United States)

    Krop, Emma M; Hetherington, Marion M; Nekitsing, Chandani; Miquel, Sophie; Postelnicu, Luminita; Sarkar, Anwesha

    2018-06-01

    Food delivers energy, nutrients and a pleasurable experience. Slow eating and prolonged oro-sensory exposure to food during consumption can enhance the processes that promote satiation. This systematic review and meta-analysis investigated the effects of oral processing on subjective measures of appetite (hunger, desire to eat) and objectively measured food intake. The aim was to investigate the influence of oral processing characteristics, specifically "chewing" and "lubrication", on "appetite" and "food intake". A literature search of six databases (Cochrane library, PubMed, Medline, Food Science and Technology Abstracts, Web of Science, Scopus), yielded 12161 articles which were reduced to a set of 40 articles using pre-specified inclusion and exclusion criteria. A further two articles were excluded from the meta-analysis due to missing relevant data. From the remaining 38 papers, detailing 40 unique studies with 70 subgroups, raw data were extracted for meta-analysis (food intake n = 65, hunger n = 22 and desire to eat ratings n = 15) and analyzed using random effects modelling. Oral processing parameters, such as number of chews, eating rate and texture manipulation, appeared to influence food intake markedly but appetite ratings to a lesser extent. Meta-analysis confirmed a significant effect of the direct and indirect aspects of oral processing that were related to chewing on both self-reported hunger (-0.20 effect size, 95% confidence interval CI: -0.30, -0.11), and food intake (-0.28 effect size, 95% CI: -0.36, -0.19). Although lubrication is an important aspect of oral processing, few studies on its effects on appetite have been conducted. Future experiments using standardized approaches should provide a clearer understanding of the role of oral processing, including both chewing and lubrication, in promoting satiety. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Effect of Probiotics on Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

    Directory of Open Access Journals (Sweden)

    Ruixue Huang

    2016-08-01

    Full Text Available It has been reported that gut probiotics play a major role in the bidirectional communication between the gut and the brain. Probiotics may be essential to people with depression, which remains a global health challenge, as depression is a metabolic brain disorder. However, the efficacy of probiotics for depression is controversial. This study aimed to systematically review the existing evidence on the effect of probiotics-based interventions on depression. Randomized, controlled trials, identified through screening multiple databases and grey literature, were included in the meta-analysis. The meta-analysis was performed using Review Manager 5.3 software using a fixed-effects model. The meta-analysis showed that probiotics significantly decreased the depression scale score (MD (depressive disorder = −0.30, 95% CI (−0.51–−0.09, p = 0.005 in the subjects. Probiotics had an effect on both the healthy population (MD = −0.25, 95% CI (−0.47–−0.03, p = 0.03 and patients with major depressive disorder (MDD (MD = −0.73, 95% CI (−1.37–−0.09, p = 0.03. Probiotics had an effect on the population aged under 60 (MD = −0.43, 95% CI (−0.72–−0.13, p = 0.005, while it had no effect on people aged over 65 (MD = −0.18, 95% CI (−0.47–0.11, p = 0.22. This is the first systematic review and meta-analysis with the goal of determining the effect of probiotics on depression. We found that probiotics were associated with a significant reduction in depression, underscoring the need for additional research on this potential preventive strategy for depression.

  17. Association between Fever and Primary Tooth Eruption: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    A Nemezio, Mariana; Mh De Oliveira, Katharina; C Romualdo, Priscilla; M Queiroz, Alexandra; Wg Paula-E-Silva, Francisco; Ab Silva, Raquel; C Küchler, Erika

    2017-01-01

    To perform a systematic review and meta-analysis to establish if fever is associated with primary tooth eruption. Literature searches involved Pubmed, MEDLINE, Web of Science, Scopus and Cochrane. The potentially relevant studies had the full text analyzed. Only studies concerning fever during eruption period of primary tooth in humans were included. Papers in non-English language, and papers that included syndromic patients or patients with any disease were excluded. The meta-analyses were performed with Review Manager (version 5.3). Only studies that reported the results as dichotomous data were analyzed with Cochran-Mantel-Haenszel test in meta-analysis function of Review Manager 5.3. The fixed-effects model was used to evaluate the association between tooth eruption and fever. Search identified 83 potential studies. After exclusion of the duplicated studies, or were not related to the criteria of inclusion only 6 studies were selected for the systematic review. In the overall meta-analysis, no association was found [OR = 1.32 (0.88-1.96)] between fever and primary tooth eruption. However, in the subgroup analysis, when the method used to measure fever was the rectal temperature there was an association [OR = 2.82 (1.55-5.14)] between fever and primary tooth eruption. There are few suitable studies in the literature regarding the association between primary tooth eruption and fever. However, our study found an association between fever and primary tooth eruption only when rectal temperature was performed. Nemezio MA, De Oliveira KMH, Romualdo PC, Queiroz AM, Paula-e-Silva FWG, Silva RAB, Kuchler EC. Association between Fever and Primary Tooth Eruption: A Systematic Review and Meta-analysis. Int J Clin Pediatr Dent 2017;10(3):293-298.

  18. Hyperechogenicity of substantia nigra for differential diagnosis of Parkinson's disease: A meta-analysis.

    Science.gov (United States)

    Shafieesabet, Azin; Fereshtehnejad, Seyed-Mohammad; Shafieesabet, Azadeh; Delbari, Ahmad; Baradaran, Hamid Reza; Postuma, Ronald B; Lökk, Johan

    2017-09-01

    Studies have suggested that the majority of patients with Parkinson's disease have abnormal ultrasound hyperechogenicity of the substantia nigra, and that this may be useful in diagnosis. We performed a systematic review and meta-analysis to evaluate diagnostic value of substantia nigra ultrasound to differentiate Parkinson's disease from atypical parkinsonism and from essential tremor. We systematically searched PubMed and EMBASE for relevant studies published until November 2016. Eligible articles were screened, data were extracted and study quality was scored by two independent reviewers. We applied random effect models to calculate pooled estimates for the prevalence of hyperechogenicity in each condition. For final meta-analysis, 71 articles with a total number of 5730 participants (idiopathic Parkinson's disease: 4494, atypical parkinsonism: 594, essential tremor: 642) were included. The pooled prevalence rate of hyperechogenicity was 84% (95 %CI 80-87%) in idiopathic Parkinson's disease, 28% (95% CI 20-36%) in atypical parkinsonism and 15% (95% CI 7-23%) in essential tremor. Based on our meta-analysis, substantia nigra hyperechogenecity has 75% (95% CI: 60-86%) sensitivity and 70% (95% CI: 55-81%) specificity to differentiate idiopathic Parkinson's disease from atypical parkinsonism. Sensitivity and specificity to distinguish idiopathic Parkinson's disease from essential tremor was calculated as 78% (95% CI: 69-85%) and 85% (95% CI: 77-91%), respectively. Findings from our meta-analysis showed that transcranial sonography can provide useful information to differentiate idiopathic Parkinson's disease from mimicking movement disorders, although sensitivity and specificity are suboptimal, particularly for differentiating from atypical parkinsonism. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The evaluation of immunotherapy and chemotherapy treatment on melanoma: a network meta-analysis.

    Science.gov (United States)

    CiRen, BaSang; Wang, Xinhua; Long, Ziwen

    2016-12-06

    Melanoma is a highly malignant tumor that develops from a neural crest derivative called melanocytes. Chemotherapy is recommended for patients with stage III/IV melanoma. Immunomodulation has also been shown to effectively improve the survival rate of such patients. In the current study, we aimed to perform a network meta-analysis on the therapeutic value of chemotherapy and immunotherapy on melanoma. Twenty randomized controlled trials (RCTs) were enrolled in the study. Our Results indicated that ipilimumab + nivolumab had the highest response rate among all therapies, pembrolizumab also had a good efficacy with an excellent tolerance. Chemotherapy had a low response rate, high adverse effects and progressive diseases qualities, therefore it is not recommended as a preferred treatment for patients with advanced melanoma. The Cochrane library, PubMed and Embase databases were searched for relevant articles. Results of the pair-wise meta-analysis were illustrated by odd ratios (ORs) and corresponding 95% confidence intervals (CIs). Network meta-analysis was performed using a random-effects model under Bayesian framework. Results were illustrated by cumulative ORs and corresponding 95% credible interval (CrIs). The probabilities and outcomes of each treatment were ranked and summarized using the surface under the cumulative ranking curve (SUCRA). We recommend pembrolizumab as the preferred treatment due to its high efficacy and low adverse effects, combination of ipilimumab and nivolumab could be used in severe symptoms.

  20. Lorazepam or diazepam for convulsive status epilepticus: A meta-analysis.

    Science.gov (United States)

    Wu, Wei; Zhang, Liqun; Xue, Rong

    2016-07-01

    Convulsive status epilepticus (CSE) is a neurological emergency in adults and children. However, whether a particular benzodiazepine is of superior efficacy and safety in management of CSE is controversial. We performed a meta-analysis to compare the outcome of lorazepam and diazepam for treating CSE. We searched the PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar databases from 1966 to February 2014. No language restriction was applied. Reference lists of all the selected articles were hand-searched for any additional trials. Trial quality was assessed using the modified Jadad scale and the Consolidated Standards Of Reporting Trials (CONSORT) checklist. Two authors independently extracted data from all eligible studies, including study design, participants, interventions, and outcomes. The data was analyzed using fixed-effects or random-effects models with mean differences and risk ratios for continuous and dichotomous variables, respectively. A total of six studies involving 970 patients were included in this analysis. The majority of patients were children (n=574) and 396 patients were adults. Meta-analysis showed no significant difference between the two treatment groups regarding seizure control and adverse effects regardless of patient age. This meta-analysis demonstrates that diazepam and lorazepam have equal efficacy and side effects for treating CSE in adults and children, and either can be chosen as a reasonable first-line therapy. More high quality randomized controlled trials are needed to support this finding. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Prevalence of Enterobius vermicularis among Children in Iran: A Systematic Review and Meta-analysis

    Science.gov (United States)

    Moosazadeh, Mahmood; Abedi, Ghasem; Afshari, Mahdi; Mahdavi, Seif Ali; Farshidi, Fereshteh; Kheradmand, Elham

    2017-01-01

    Objectives Enterobius vermicularis is a parasitic disease that is common in crowded areas such as schools and kindergartens. Primary investigations of electronic evidence have reported different prevalences of E. vermicularis in Iran. Therefore, we aimed to estimate the total prevalence of this infection among Iranian children using a meta-analysis. Methods Relevant studies were identified in national and international databases. We selected eligible papers for meta-analysis after investigating titles, abstracts, and full texts; assessing study quality; and applying inclusion/exclusion criteria. Data were extracted by two independent researchers. The results were combined using a random effects model in Stata v. 11 software. Results Among 19 eligible articles including 11,676 participants, the prevalences of E. vermicularis among all children, boys, and girls were 1.2%–66.1%, 2.3%–65.5%, and 1.7%–65.5%, respectively. Pooled prevalences (95% confidence interval) of E. vermicularis among all children, boys, and girls were 17.2% (12.6%–21.8%), 17.2% (12.6%–21.8%), and 16.9% (9.03%–24.8%), respectively. Conclusion This meta-analysis showed that a great majority of Iranian children are infected with E. vermicularis, possibly due to poor public health. PMID:28540154

  2. Prevalence ofEnterobius vermicularisamong Children in Iran: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Moosazadeh, Mahmood; Abedi, Ghasem; Afshari, Mahdi; Mahdavi, Seif Ali; Farshidi, Fereshteh; Kheradmand, Elham

    2017-04-01

    Enterobius vermicularis is a parasitic disease that is common in crowded areas such as schools and kindergartens. Primary investigations of electronic evidence have reported different prevalences of E. vermicularis in Iran. Therefore, we aimed to estimate the total prevalence of this infection among Iranian children using a meta-analysis. Relevant studies were identified in national and international databases. We selected eligible papers for meta-analysis after investigating titles, abstracts, and full texts; assessing study quality; and applying inclusion/exclusion criteria. Data were extracted by two independent researchers. The results were combined using a random effects model in Stata v. 11 software. Among 19 eligible articles including 11,676 participants, the prevalences of E. vermicularis among all children, boys, and girls were 1.2%-66.1%, 2.3%-65.5%, and 1.7%-65.5%, respectively. Pooled prevalences (95% confidence interval) of E. vermicularis among all children, boys, and girls were 17.2% (12.6%-21.8%), 17.2% (12.6%-21.8%), and 16.9% (9.03%-24.8%), respectively. This meta-analysis showed that a great majority of Iranian children are infected with E. vermicularis , possibly due to poor public health.

  3. Associations between depression and specific childhood experiences of abuse and neglect: A meta-analysis.

    Science.gov (United States)

    Infurna, Maria Rita; Reichl, Corinna; Parzer, Peter; Schimmenti, Adriano; Bifulco, Antonia; Kaess, Michael

    2016-01-15

    Research documents a strong relationship between childhood maltreatment and depression. However, only few studies have examined the specific effects of various types of childhood abuse/neglect on depression. This meta-analysis estimated the associations between depression and different types of childhood maltreatment (antipathy, neglect, physical abuse, sexual abuse, and psychological abuse) assessed with the same measure, the Childhood Experience of Care and Abuse (CECA) interview. A systematic search in scientific databases included use of CECA interview and strict clinical assessment for major depression as criteria. Our meta-analysis utilized Cohen's d and relied on a random-effects model. The literature search yielded 12 primary studies (reduced from 44), with a total of 4372 participants and 34 coefficients. Separate meta-analyses for each type of maltreatment revealed that psychological abuse and neglect were most strongly associated with the outcome of depression. Sexual abuse, although significant, was less strongly related. Furthermore, the effects of specific types of childhood maltreatment differed across adult and adolescent samples. Our strict criteria for selecting the primary studies resulted in a small numbers of available studies. It restricted the analyses for various potential moderators. This meta-analysis addressed the differential effects of type of childhood maltreatment on major depression, partially explaining between-study variance. The findings clearly highlight the potential impact of the more "silent" types of childhood maltreatment (other than physical and sexual abuse) on the development of depression. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Risk associated with central catheters for malignant tumor patients: a systematic review and meta-analysis.

    Science.gov (United States)

    Lv, Yajuan; Hou, Yong; Pan, Bo; Ma, Yuwan; Li, Paiyun; Yu, Lili; Xu, Deguo; Song, Juanjuan; Shang, Heli; Wang, Hongyan; Tian, Yuan

    2018-02-23

    The risk of venous thrombosis and mortality associated with central catheter (PICC/CICC) for malignant tumor patients is not definite. So, we carried out a systematic review and meta-analysis to evaluate it. Among patients with comparing PICC with CICC, odds ratio (OR) or risk ratio (RR) was calculated with a random effect model meta-analysis. The result of the stratification analysis of 7 studies (PICC vs CICC) supported the theory that CICCs were associated with a decrease in the odds ratio of thrombosis compared with PICCs. 7 of 15 studies provided the information about the compared mortality rate of the patients. The result showed that CICCs were associated with a decrease in the odds ratio of thrombosis compared with PICCs (OR = 0.45, 95% CI:0.32-0.62, p < 0.0001, I 2 = 0%,Tau 2 = 0.00). Meta-analysis of 8 studies of 2639 patients showed that pharmacological deep vein thrombosis prophylaxis drugs could decrease the risk of mortality of malignant tumor patients with CICCs (RR = 0.58, 95% CI:0.48-0.71, Z = 5.32, p < 0.0001, I 2 = 71%). We found that PICCs are associated with a raised risk of deep vein thrombosis, and pharmacological deep vein thrombosis prophylaxis drugs is a beneficial factor in decreasing the incidence of thrombosis, while warfarin may decrease the risk of mortality of malignant tumor patients with CICCs.

  5. Liposomal bupivacaine versus traditional bupivacaine for pain control after total hip arthroplasty: A meta-analysis.

    Science.gov (United States)

    Ma, Ting-Ting; Wang, Yu-Hui; Jiang, Yun-Feng; Peng, Cong-Bin; Yan, Chao; Liu, Zi-Gui; Xu, Wei-Xing

    2017-06-01

    In the past, the efficacy of local infiltration of liposomal bupivacaine for total hip arthroplasty (THA) patients was in debate. Therefore, this meta-analysis was conducted to determine whether local infiltration of liposomal bupivacaine provides better pain relief after THA. We searched Web of Science, PubMed, Embase, and the Cochrane Library databases to the April 2017. Any studies comparing liposomal bupivacaine and traditional bupivacaine were included in our meta-analysis. The outcomes included visual analog scale (VAS) at 24, 48, and 72 hours, total morphine consumption at 24 hours, and the length of hospital stay. We assessed the pooled data using a random-effect model. Six studies were finally included in this meta-analysis. Our pooled data analysis demonstrated that liposomal bupivacaine was more effective than the traditional bupivacaine in terms of VAS at 24 hours (P  =  .018) and the length of hospital stay (P  =  .000). There was no significant difference in terms of the VAS at 48 and 72 hours and total morphine consumption at 24 hours (P >.05). Compared with the traditional bupivacaine, liposomal bupivacaine shows better pain control at 24 hours and reduces the length of hospital stay after THA. Its economic costs must be assessed in multimodal center randomized controlled trials when being recommended as a long-acting alternative analgesic agent for a THA patient.

  6. Dietary zinc and iron intake and risk of depression: A meta-analysis.

    Science.gov (United States)

    Li, Zongyao; Li, Bingrong; Song, Xingxing; Zhang, Dongfeng

    2017-05-01

    The associations between dietary zinc and iron intake and risk of depression remain controversial. Thus, we carried out a meta-analysis to evaluate these associations. A systematic search was performed in PubMed, Embase, Web of Science, Chinese National Knowledge Infrastructure (CNKI) and Wanfang databases for relevant studies up to January 2017. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random effects model. A total of 9 studies for dietary zinc intake and 3 studies for dietary iron intake were finally included in present meta-analysis. The pooled RRs with 95% CIs of depression for the highest versus lowest dietary zinc and iron intake were 0.67 (95% CI: 0.58-0.76) and 0.57 (95% CI: 0.34-0.95), respectively. In subgroup analysis by study design, the inverse association between dietary zinc intake and risk of depression remained significant in the cohort studies and cross-sectional studies. The pooled RRs (95% CIs) for depression did not substantially change in the influence analysis and subgroup analysis by adjustment for body mass index (BMI). The present meta-analysis indicates inverse associations between dietary zinc and iron intake and risk of depression. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  7. The association between dietary zinc intake and risk of pancreatic cancer: a meta-analysis.

    Science.gov (United States)

    Li, Li; Gai, Xuesong

    2017-06-30

    Previous reports have suggested a potential association on dietary zinc intake with the risk of pancreatic cancer. Since the associations between different studies were controversial, we therefore conducted a meta-analysis to reassess the relationship between dietary zinc intake and pancreatic cancer risk. A comprehensive search from the databases of PubMed, Embase, Web of Science, and Medline was performed until January 31, 2017. Relative risk (RR) with 95% confidence intervals (CI) derived by using random effect model was used. Sensitivity analysis and publication bias were conducted. Our meta-analysis was based on seven studies involving 1659 cases, including two prospective cohort studies and five case-control studies. The total RR of pancreatic cancer risk for the highest versus the lowest categories of dietary zinc intake was 0.798 (0.621-0.984), with its significant heterogeneity among studies ( I 2 =58.2%, P =0.026). The average Newcastle-Ottawa scale (NOS) score was 7.29, suggesting a high quality. There was no publication bias in the meta-analysis about dietary zinc intake on the risk of pancreatic cancer. Subgroup analyses showed that dietary zinc intake could reduce the risk of pancreatic cancer in case-control studies and among American populations. In conclusion, we found that highest category of dietary zinc intake can significantly reduce the risk of pancreatic cancer, especially among American populations. © 2017 The Author(s).

  8. Association of LPP and TAGAP Polymorphisms with Celiac Disease Risk: A Meta-Analysis

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    Shi-Qi Huang

    2017-02-01

    Full Text Available Background: Lipoma preferred partner (LPP and T-cell activation Rho GTPase activating protein (TAGAP polymorphisms might influence the susceptibility to celiac disease. Therefore, we performed a meta-analysis by identifying relevant studies to estimate the risks of these polymorphisms on celiac disease. Methods: The PubMed, Web of Science and Embase databases were searched (up to October 2016 for LPP rs1464510 and TAGAP rs1738074 polymorphisms. Results: This meta-analysis included the same 7 studies for LPP rs1464510 and TAGAP rs1738074. The minor risk A allele at both rs1464510 and rs1738074 carried risks (odds ratios of 1.26 (95% CI: 1.22–1.30 and 1.17 (95% CI: 1.14–1.21, respectively, which contributed to increased risks in all celiac disease patients by 10.72% and 6.59%, respectively. The estimated lambdas were 0.512 and 0.496, respectively, suggesting that a co-dominant model would be suitable for both gene effects. Conclusions: This meta-analysis provides robust estimates that polymorphisms in LPP and TAGAP genes are potential risk factors for celiac disease in European and American. Prospective studies and more genome-wide association studies (GWAS are needed to confirm these findings, and some corresponding molecular biology experiments should be carried out to clarify the pathogenic mechanisms of celiac disease.

  9. The effects of aromatherapy on sleep improvement: a systematic literature review and meta-analysis.

    Science.gov (United States)

    Hwang, Eunhee; Shin, Sujin

    2015-02-01

    To evaluate the existing data on aromatherapy interventions for improvement of sleep quality. Systematic literature review and meta-analysis on the effects of aromatherapy. Study Sources: Electronic databases, including the Korea Education and Research Information Service (KERIS), Korean studies Information Service System (KISS), National Assembly Library, and eight academies within the Korean Society of Nursing Science, were searched to identify studies published between 2000 and August 2013. Randomized controlled and quasi-experimental trials that included aromatherapy for the improvement of sleep quality. Of the 245 publications identified, 13 studies met the inclusion and exclusion criteria, and 12 studies were used in the meta-analysis. Meta-analysis of the 12 studies using a random-effects model revealed that the use of aromatherapy was effective in improving sleep quality (95% confidence interval [CI], 0.540-1.745; Z=3.716). Subgroup analysis revealed that inhalation aromatherapy (95% CI, 0.792-1.541; Z=6.107) was more effective than massage therapy (95% CI, 0.128-2.166; Z=2.205) in unhealthy (95% CI, 0.248-1.100; Z=3.100) and healthy (95% CI, 0.393-5.104; Z=2.287) participants, respectively. Readily available aromatherapy treatments appear to be effective and promote sleep. Thus, it is essential to develop specific guidelines for the efficient use of aromatherapy.

  10. Survival after radiotherapy in gastric cancer: Systematic review and meta-analysis

    International Nuclear Information System (INIS)

    Valentini, Vincenzo; Cellini, Francesco; Minsky, Bruce D.; Mattiucci, Gian Carlo; Balducci, Mario; D'Agostino, Giuseppe; D'Angelo, Elisa; Dinapoli, Nicola; Nicolotti, Nicola; Valentini, Chiara; La Torre, Giuseppe

    2009-01-01

    Background and purpose: A systematic review and meta-analysis was performed to assess the impact of radiotherapy on both 3- and 5-year survival in patients with resectable gastric cancer. Methods: Randomized Clinical Trials (RCTs) in which radiotherapy, (preoperative, postoperative and/or intraoperative), was compared with surgery alone or surgery plus chemotherapy in resectable gastric cancer were identified by searching web-based databases and supplemented by manual examination of reference lists. Meta-analysis was performed using Risk Ratios (RRs). Random or fixed effects models were used to combine data. The methodological quality was evaluated by Chalmers' score. Results: Radiotherapy had a significant impact on 5-year survival. Using an intent to treat (ITT) and a Per Protocol (PP) analysis, the overall 5-year RR was 1.26 (95% CI: 1.08-1.48; NNT = 17) and 1.31 (95% CI: 1.04-1.66; NNT = 13), respectively. Although the quality of the studies was variable, the data were consistent and no clear publication bias was found. Conclusion: This meta-analysis showed a statistically significant 5-year survival benefit with the addition of radiotherapy in patients with resectable gastric cancer. Radiotherapy remains a standard component in the treatment of resectable gastric cancer and new RCTs need to address the impact of new conformal radiotherapy technologies.

  11. Circulating Resistin Levels and Risk of Colorectal Cancer: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Gui Yang

    2016-01-01

    Full Text Available Objectives. Published data on resistin levels in patients with colorectal cancer (CRC were conflicting and heterogeneous. We conducted a meta-analysis of observational studies to examine the association of circulating resistin levels with carcinogenesis of the CRC. Methods. Potentially eligible studies published up to November 2015 were searched through MEDLINE, EMBASE, Science Citation Index Expanded database, CNKI, and WanFang database. The pooled weighted mean differences (WMDs with 95% confidence intervals (CIs calculated by fixed- or random-effect model were used to estimate the effects. Results. A total of 11 studies involving 965 patients were admitted in our meta-analysis. The pooled effects indicated that resistin levels were higher in CRC patients compared to healthy controls (WMD: 1.47 ng/mL; 95% CI: 0.78 to 2.16, with significant heterogeneity across the studies (I2=72%, p<0.0001. Subgroup analyses and sensitivity analyses revealed that study quality, design, sample type, and resistin assays may account for this heterogeneity. No publication bias was observed. Conclusions. Our meta-analysis suggests that increased circulating resistin levels are associated with greater risk of colorectal cancer. Given the limited number of available studies and significant heterogeneity, larger well-designed randomized studies are warranted.

  12. Multiple imputation for IPD meta-analysis: allowing for heterogeneity and studies with missing covariates.

    Science.gov (United States)

    Quartagno, M; Carpenter, J R

    2016-07-30

    Recently, multiple imputation has been proposed as a tool for individual patient data meta-analysis with sporadically missing observations, and it has been suggested that within-study imputation is usually preferable. However, such within study imputation cannot handle variables that are completely missing within studies. Further, if some of the contributing studies are relatively small, it may be appropriate to share information across studies when imputing. In this paper, we develop and evaluate a joint modelling approach to multiple imputation of individual patient data in meta-analysis, with an across-study probability distribution for the study specific covariance matrices. This retains the flexibility to allow for between-study heterogeneity when imputing while allowing (i) sharing information on the covariance matrix across studies when this is appropriate, and (ii) imputing variables that are wholly missing from studies. Simulation results show both equivalent performance to the within-study imputation approach where this is valid, and good results in more general, practically relevant, scenarios with studies of very different sizes, non-negligible between-study heterogeneity and wholly missing variables. We illustrate our approach using data from an individual patient data meta-analysis of hypertension trials. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd. © 2015 The Authors. Statistics in Medicine Published by John Wiley & Sons Ltd.

  13. Effect of Tamsulosin on Stone Passage for Ureteral Stones: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Wang, Ralph C; Smith-Bindman, Rebecca; Whitaker, Evans; Neilson, Jersey; Allen, Isabel Elaine; Stoller, Marshall L; Fahimi, Jahan

    2017-03-01

    Tamsulosin is recommended for patients receiving a diagnosis of a ureteral stone less than 10 mm who do not require immediate urologic intervention. Because of conflicting results from recent meta-analyses and large randomized controlled trials, the efficacy of tamsulosin is unclear. We perform a systematic review and meta-analysis to investigate the effect of tamsulosin on stone passage in patients receiving a diagnosis of ureteral stone. MEDLINE, EMBASE, and CENTRAL databases were searched without language restriction through November 2015 for studies assessing the efficacy of tamsulosin and using a double-blind, randomized, controlled trial design. Meta-analysis was conducted with a random-effects model and subgroup analyses were conducted to determine sources of heterogeneity. Eight randomized controlled trials (N=1,384) contained sufficient information for inclusion. The pooled risk of stone passage in the tamsulosin arm was 85% versus 66% in the placebo arm, but substantial heterogeneity existed across trials (I 2 =80.2%; Ptamsulosin (risk difference=22%; 95% confidence interval 12% to 33%; number needed to treat=5). The meta-analysis of the small stone subgroup (Tamsulosin significantly improves stone passage in patients with larger stones, whereas the effect of tamsulosin is diminished in those with smaller stones, who are likely to pass their stone regardless of treatment. Copyright © 2016 American College of Emergency Physicians. Published by Elsevier Inc. All rights reserved.

  14. Meta-analysis: Association of Helicobacter pylori infection with Parkinson's diseases.

    Science.gov (United States)

    Shen, Xiaoli; Yang, Huazhen; Wu, Yili; Zhang, Dongfeng; Jiang, Hong

    2017-10-01

    The results from observational studies on the relationship between helicobacter pylori (H. pylori) infection and Parkinson's disease remain controversial. A meta-analysis was conducted to evaluate the association between helicobacter pylori infection and Parkinson's disease. A comprehensive literature search was performed on relevant studies published from January 1983 to January 2017 in PubMed, Web of Science and EMBASE databases. The fixed or random effects model was used to pool the odds ratio with 95% confidence interval from individual studies. Publication bias was estimated by Egger's test and the funnel plot. Eight eligible studies involving 33 125 participants were included in this meta-analysis. Compared with the no helicobacter pylori infected person, the pooled odds ratio of Parkinson's disease in helicobacter pylori infected person was 1.59 (95% confidence interval: 1.37-1.85). In subgroup analyzes, the combined odds ratios were 1.96 (1.23-3.12) in Asia, 1.55 (1.32-1.82) in Europe, 1.59 (1.35-1.88) in case-control studies, 1.56 (1.01-2.39) in cross-sectional studies, 1.56 (1.32-1.85) in studies with confounders adjusted, and 1.71 (1.21-2.43) in studies with no confounder adjusted, respectively. This meta-analysis indicated that H. pylori infection might be associated with the risk of Parkinson's disease. © 2017 John Wiley & Sons Ltd.

  15. Systemic Oxidative Stress Biomarkers in Chronic Periodontitis: A Meta-Analysis

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    Zhiqiang Liu

    2014-01-01

    Full Text Available Oxidative stress biomarkers have been observed in peripheral blood of chronic periodontitis patients; however, their associations with periodontitis were not consistent. This meta-analysis was performed to clarify the associations between chronic periodontitis and oxidative biomarkers in systemic circulation. Electronic searches of PubMed and Embase databases were performed until October 2014 and articles were selected to meet inclusion criteria. Data of oxidative biomarkers levels in peripheral blood of periodontitis patients and periodontal healthy controls were extracted to calculate standardized mean differences (SMDs and 95% confidence intervals (CIs by using random-effects model. Of 31 eligible articles, 16 articles with available data were included in meta-analysis. Our results showed that periodontitis patients had significantly lower levels of total antioxidant capacity (SMD = −2.02; 95% CI: −3.08, −0.96; P=0.000 and higher levels of malondialdehyde (SMD = 0.99; 95% CI: 0.12, 1.86; P=0.026 and nitric oxide (SMD = 4.98; 95% CI: 2.33, 7.63; P=0.000 than periodontal healthy control. Superoxide dismutase levels between two groups were not significantly different (SMD = −1.72; 95% CI: −3.50, 0.07; P=0.059. In conclusion, our meta-analysis showed that chronic periodontitis is significantly associated with circulating levels of three oxidative stress biomarkers, indicating a role of chronic periodontitis in systemic diseases.

  16. Associations between interleukin-1 gene polymorphisms and coronary heart disease risk: a meta-analysis.

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    Liang Zhou

    Full Text Available OBJECTIVE: A great number of studies regarding the associations between IL-1B-511, IL-1B+3954 and IL-1RN VNTR polymorphisms within the IL-1gene cluster and coronary heart disease (CHD have been published. However, results have been inconsistent. In this study, a meta-analysis was performed to investigate the associations. METHODS: Published literature from PubMed and Embase databases were searched for eligible publications. Pooled odds ratios (ORs with 95% confidence intervals (CIs were calculated using random- or fixed- effect model. RESULTS: Thirteen studies (3,219 cases/2,445 controls for IL-1B-511 polymorphism, nine studies (1,828 cases/1,818 controls for IL-1B+3954 polymorphism and twelve studies (2,987 cases/ 2,208 controls for IL-1RN VNTR polymorphism were included in this meta analysis. The results indicated that both IL-1B-511 and IL-1B+3954 polymorphisms were not associated with CHD risk (IL-1B-511 T vs. C: OR = 0.98, 95%CI 0.87-1.09; IL-1B+3954 T vs. C: OR = 1.06, 95%CI 0.95-1.19. Similarly, there was no association between IL-1RN VNTR polymorphism and CHD risk (*2 vs. L: OR = 1.00, 95%CI 0.85-1.17. CONCLUSIONS: This meta-analysis suggested that there were no associations between IL-1 gene cluster polymorphisms and CHD.

  17. Quantifying the dose-response of walking in reducing coronary heart disease risk: meta-analysis.

    Science.gov (United States)

    Zheng, Henry; Orsini, Nicola; Amin, Janaki; Wolk, Alicja; Nguyen, Van Thi Thuy; Ehrlich, Fred

    2009-01-01

    The evidence for the efficacy of walking in reducing the risk of and preventing coronary heart disease (CHD) is not completely understood. This meta-analysis aimed to quantify the dose-response relationship between walking and CHD risk reduction for both men and women in the general population. Studies on walking and CHD primary prevention between 1954 and 2007 were identified through Medline, SportDiscus and the Cochrane Database of Systematic Reviews. Random-effect meta-regression models were used to pool the relative risks from individual studies. A total of 11 prospective cohort studies and one randomized control trial study met the inclusion criteria, with 295,177 participants free of CHD at baseline and 7,094 cases at follow-up. The meta-analysis indicated that an increment of approximately 30 min of normal walking a day for 5 days a week was associated with 19% CHD risk reduction (95% CI = 14-23%; P-heterogeneity = 0.56; I (2) = 0%). We found no evidence of heterogeneity between subgroups of studies defined by gender (P = 0.67); age of the study population (P = 0.52); or follow-up duration (P = 0.77). The meta-analysis showed that the risk for developing CHD decreases as walking dose increases. Walking should be prescribed as an evidence-based effective exercise modality for CHD prevention in the general population.

  18. The Effect of Hypnosis on Anxiety in Patients With Cancer: A Meta-Analysis.

    Science.gov (United States)

    Chen, Pei-Ying; Liu, Ying-Mei; Chen, Mei-Ling

    2017-06-01

    Anxiety is a common form of psychological distress in patients with cancer. One recognized nonpharmacological intervention to reduce anxiety for various populations is hypnotherapy or hypnosis. However, its effect in reducing anxiety in cancer patients has not been systematically evaluated. This meta-analysis was designed to synthesize the immediate and sustained effects of hypnosis on anxiety of cancer patients and to identify moderators for these hypnosis effects. Qualified studies including randomized controlled trials (RCT) and pre-post design studies were identified by searching seven electronic databases: Scopus, Medline Ovidsp, PubMed, PsycInfo-Ovid, Academic Search Premier, CINAHL Plus with FT-EBSCO, and SDOL. Effect size (Hedges' g) was computed for each study. Random-effect modeling was used to combine effect sizes across studies. All statistical analyses were conducted with Comprehensive Meta-Analysis, version 2 (Biostat, Inc., Englewood, NJ, USA). Our meta-analysis of 20 studies found that hypnosis had a significant immediate effect on anxiety in cancer patients (Hedges' g: 0.70-1.41, p Hypnosis delivered by a therapist was significantly more effective than self-hypnosis. Hypnosis can reduce anxiety of cancer patients, especially for pediatric cancer patients who experience procedure-related stress. We recommend therapist-delivered hypnosis should be preferred until more effective self-hypnosis strategies are developed. © 2017 Sigma Theta Tau International.

  19. Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis

    Science.gov (United States)

    Fan, Dazhi; Wu, Song; Liu, Li; Xia, Qing; Wang, Wen; Guo, Xiaoling; Liu, Zhengping

    2017-01-01

    Antepartum hemorrhage (APH) is an important cause of perinatal mortality and maternal morbidity in pregnant women with placenta previa in the world. However, the epidemiological characteristics are not completely understood. We performed an initial systematic review and meta-analysis to assess the prevalence of APH in pregnant women with placenta previa. It was totally performed following the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. PubMed, Elsevier Science Direct, and the Cochrane Library were searched before April 2016. A meta-analysis with a random-effects model based on a proportions approach was performed to determine the prevalence. Stratified analyses, meta-regression method, and sensitivity analysis were utilized to analyze the heterogeneity. A total of 29 articles were included. The pooled overall prevalence of APH among pregnant women with placenta previa was 51.6% (95% CI 42.7–60.6) in a heterogeneous set of studies (I2 = 97.9). Correlation analysis found that there was a positive correlation between prevalence and percentage of multiparous (r = 0.534, P = 0.027) and a negative correlation between prevalence and survey year (r = −0.400, P = 0.031). In conclusion, the prevalence of APH was a high condition among pregnant women with placenta previa. PMID:28067303

  20. Tea consumption may decrease the risk of osteoporosis: an updated meta-analysis of observational studies.

    Science.gov (United States)

    Guo, Ming; Qu, Hua; Xu, Lin; Shi, Da-Zhuo

    2017-06-01

    Several epidemiological investigations have evaluated the correlation between tea consumption and risk of osteoporosis, but the results are inconsistent. Therefore, we conducted an updated meta-analysis of observational studies to assess this association. We searched for all relevant studies including cohort, cross-sectional, and case-control studies published from database inception to July 15, 2016, using MEDLINE EMBASE, and Cochrane Library. Polled odds ratios (ORs) were calculated using the random-effect model. Fourteen articles (16 studies) that examined 138523 patients were included in this meta-analysis. Seven studies concerning bone mineral density (BMD) showed an increase in BMD with tea consumption, including 4 cross-sectional studies (OR, 0.04, 95% confidence interval [CI], 0.01-0.08) and 3 cohort studies (OR, 0.01; 95% CI, 0.01-0.01). The remaining 9 studies concerning fracture, including 6 case-control studies and 3 cohort studies, showed no association between tea consumption and osteoporotic fracture (OR, 0.86; 95% CI, 0.74-1.01). This updated meta-analysis demonstrates that tea consumption could increase BMD, but the association with osteoporotic fracture requires further investigation. Together, the results highlight the need for future, high-quality-designed clinical trials on tea consumption and osteoporosis. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Exposure to organochlorine pollutants and type 2 diabetes: a systematic review and meta-analysis.

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    Mengling Tang

    Full Text Available OBJECTIVE: Though exposure to organochlorine pollutants (OCPs is considered a risk factor for type 2 diabetes (T2DM, epidemiological evidence for the association remains controversial. A systematic review and meta-analysis was applied to quantitatively evaluate the association between exposure to OCPs and incidence of T2DM and pool the inconsistent evidence. DESIGN AND METHODS: Publications in English were searched in MEDLINE and WEB OF SCIENCE databases and related reference lists up to August 2013. Quantitative estimates and information regarding study characteristics were extracted from 23 original studies. Quality assessments of external validity, bias, exposure measurement and confounding were performed, and subgroup analyses were conducted to examine the heterogeneity sources. RESULTS: We retrieved 23 eligible articles to conduct this meta-analysis. OR (odds ratio or RR (risk ratio estimates in each subgroup were discussed, and the strong associations were observed in PCB-153 (OR, 1.52; 95% CI, 1.19-1.94, PCBs (OR, 2.14; 95% CI, 1.53-2.99, and p,p'-DDE (OR, 1.33; 95% CI, 1.15-1.54 based on a random-effects model. CONCLUSIONS: This meta-analysis provides quantitative evidence supporting the conclusion that exposure to organochlorine pollutants is associated with an increased risk of incidence of T2DM.

  2. Nerve growth factor for Bell’s palsy: A meta-analysis

    Science.gov (United States)

    SU, YIPENG; DONG, XIAOMENG; LIU, JUAN; HU, YAOZHI; CHEN, JINBO

    2015-01-01

    A meta-analysis was performed to evaluate the efficacy and safety of nerve growth factor (NGF) in the treatment of Bell’s palsy. PubMed, the Cochrane Central Register of Controlled Trials, Embase and a number of Chinese databases, including the China National Knowledge Infrastructure, China Biology Medicine disc, VIP Database for Chinese Technical Periodicals and Wan Fang Data, were used to collect randomised controlled trials (RCTs) of NGF for Bell’s palsy. The span of the search covered data from the date of database establishment until December 2013. The included trials were screened comprehensively and rigorously. The efficacies of NGF were pooled via meta-analysis performed using Review Manager 5.2 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using the fixed-effects model. The meta-analysis of eight RCTs showed favorable effects of NGF on the disease response rate (n=642; OR, 3.87; 95% CI, 2.13–7.03; PBell’s palsy is limited. The number and quality of trials are too low to form solid conclusions. Further meticulous RCTs are required to overcome the limitations identified in the present study. PMID:25574223

  3. The effectiveness of interprofessional education in healthcare: A systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Salman Yousuf Guraya

    2018-03-01

    Full Text Available Interprofessional education (IPE emphasizes collaborative practice that aims at promoting the working relationships between two or more healthcare professions. However, there is paucity of literature about the effectiveness of IPE program in the healthcare. This systematic review and meta-analysis aims to objectively determine the effectiveness of IPE in that field in terms of the improvement of students' knowledge, skills and attitudes. The databases of OVID, ISI Knowledge of Science, and Medline (PubMed were searched for the full-text English language articles published during 2000–2016 using the MeSH terms “interprofessional education” AND “healthcare professionals” AND “multi-professional” AND “impact” AND “effectiveness” OR “collaborative practice” OR “medical students” in Endnote X7. A systematic search finally selected 12 articles for detailed review and meta-analysis. The effect summary value of 1.37 with confidence interval of 0.92–1.82 identifies statistically significant effectiveness of intervention by IPE program in healthcare. The Z test value of 5.99, significant at 5% level of significance, also shows a significant impact of IPE intervention as calculated by the random-effects model. This meta-analysis shows a positive impact and effectiveness of educational intervention by IPE program in various disciplines of healthcare. However, analysis of further clinical trials may be helpful in identifying the effect of IPE program on the students’ clinical competence.

  4. Meta-analysis on shift work and risks of specific obesity types.

    Science.gov (United States)

    Sun, M; Feng, W; Wang, F; Li, P; Li, Z; Li, M; Tse, G; Vlaanderen, J; Vermeulen, R; Tse, L A

    2018-01-01

    This systematic review and meta-analysis evaluated the associations between shift work patterns and risks of specific types of obesity. PubMed was searched until March 2017 for observational studies that examined the relationships between shift work patterns and obesity. Odds ratio for obesity was extracted using a fixed-effects or random-effects model. Subgroup meta-analyses were carried out for study design, specific obesity types and characteristics of shift work pattern. A total of 28 studies were included in this meta-analysis. The overall odds ratio of night shift work was 1.23 (95% confidence interval = 1.17-1.29) for risk of obesity/overweight. Cross-sectional studies showed a higher risk of 1.26 than those with the cohort design (risk ratio = 1.10). Shift workers had a higher frequency of developing abdominal obesity (odds ratio = 1.35) than other obesity types. Permanent night workers demonstrated a 29% higher risk than rotating shift workers (odds ratio 1.43 vs. 1.14). This meta-analysis confirmed the risks of night shift work for the development of overweight and obesity with a potential gradient association suggested, especially for abdominal obesity. Modification of working schedules is recommended, particularly for prolonged permanent night work. More accurate and detailed measurements on shift work patterns should be conducted in future research. © 2017 World Obesity Federation.

  5. Prevalence of retinopathy of prematurity in Iran: asystematic review and Meta-analysis

    Directory of Open Access Journals (Sweden)

    Saman Maroufizadeh

    2017-08-01

    Full Text Available AIM: To estimate overall prevalence of retinopathy of prematurity (ROP in Iran using a systematic review and Meta-analysis. METHODS: A systematic review and Meta-analysis was performed of all published studies pertaining to prevalence of ROP using international and national electronic databases (ISI Web of Sciences, PubMed, Scopus, Google Scholar, SID, MagIran, and IranMedex from their inception until May 2016 with standard keywords. Begg and Egger tests were used to examine the publication bias and Cochran test and I2 statistics were used to evaluate the statistical heterogeneity. Pooled estimate of the prevalence of ROP were calculated using random effects Meta-analysis. RESULTS: The publication bias assumption was rejected by Egger tests with P-value equal to 0.024. The results of Cochran test and I2 statistics revealed substantial heterogeneity (Q=1099.02, df=25, I2=97.7%, P=0.001. The overall prevalence of ROP using the random effect model in Iran was 26.1% (95% CI: 20.3%-31.8%. CONCLUSION: The prevalence of ROP is relatively high in Iran. Low birth weight and gestational age are significant risk factors for the disease. Improved care, including oxygen delivery and monitoring, for preterm babies in all facility settings would reduce the number of babies affected with ROP.

  6. Meta-DiSc: a software for meta-analysis of test accuracy data.

    Science.gov (United States)

    Zamora, Javier; Abraira, Victor; Muriel, Alfonso; Khan, Khalid; Coomarasamy, Arri

    2006-07-12

    Systematic reviews and meta-analyses of test accuracy studies are increasingly being recognised as central in guiding clinical practice. However, there is currently no dedicated and comprehensive software for meta-analysis of diagnostic data. In this article, we present Meta-DiSc, a Windows-based, user-friendly, freely available (for academic use) software that we have developed, piloted, and validated to perform diagnostic meta-analysis. Meta-DiSc a) allows exploration of heterogeneity, with a variety of statistics including chi-square, I-squared and Spearman correlation tests, b) implements meta-regression techniques to explore the relationships between study characteristics and accuracy estimates, c) performs statistical pooling of sensitivities, specificities, likelihood ratios and diagnostic odds ratios using fixed and random effects models, both overall and in subgroups and d) produces high quality figures, including forest plots and summary receiver operating characteristic curves that can be exported for use in manuscripts for publication. All computational algorithms have been validated through comparison with different statistical tools and published meta-analyses. Meta-DiSc has a Graphical User Interface with roll-down menus, dialog boxes, and online help facilities. Meta-DiSc is a comprehensive and dedicated test accuracy meta-analysis software. It has already been used and cited in several meta-analyses published in high-ranking journals. The software is publicly available at http://www.hrc.es/investigacion/metadisc_en.htm.

  7. Hartung-Knapp method is not always conservative compared with fixed-effect meta-analysis.

    Science.gov (United States)

    Wiksten, Anna; Rücker, Gerta; Schwarzer, Guido

    2016-07-10

    A widely used method in classic random-effects meta-analysis is the DerSimonian-Laird method. An alternative meta-analytical approach is the Hartung-Knapp method. This article reports results of an empirical comparison and a simulation study of these two methods and presents corresponding analytical results. For the empirical evaluation, we took 157 meta-analyses with binary outcomes, analysed each one using both methods and performed a comparison of the results based on treatment estimates, standard errors and associated P-values. In several simulation scenarios, we systematically evaluated coverage probabilities and confidence interval lengths. Generally, results are more conservative with the Hartung-Knapp method, giving wider confidence intervals and larger P-values for the overall treatment effect. However, in some meta-analyses with very homogeneous individual treatment results, the Hartung-Knapp method yields narrower confidence intervals and smaller P-values than the classic random-effects method, which in this situation, actually reduces to a fixed-effect meta-analysis. Therefore, it is recommended to conduct a sensitivity analysis based on the fixed-effect model instead of solely relying on the result of the Hartung-Knapp random-effects meta-analysis. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Post-Traumatic Stress Disorder, Depression and Anxiety among North Korean Refugees: A Meta-Analysis.

    Science.gov (United States)

    Taylor, Benjamin Eric; Chekaluk, Eugene; Bennett, Joanne

    2017-09-01

    Post-traumatic stress disorder is common among North Korean refugees who have fled their country for economic, financial and humanitarian reasons. Co-morbid depression and anxiety are also common among North Korean refugees, due to the difficulties they have faced within their country and during their escape journey. Depression and anxiety complicate treatment for post-traumatic stress disorder, and lead to poorer outcomes. Thus, the aim of the present study was to provide a meta-analysis of studies investigating post-traumatic stress disorder, depression, and anxiety among North Korean refugees. Selected articles were published in English, and included measures of post-traumatic stress, and/or depression and anxiety. 10 studies were included in the depression meta-analysis, and 6 in the anxiety meta-analysis. A random-effects model revealed strong, significant associations between post-traumatic stress and depression, r=0.63, 95% CI (0.51, 0.72), ppost-traumatic stress, depression and anxiety were higher among adults and those with more than five years outside of North Korea. Depression appears to be an important treatment focus for North Korean refugees with post-traumatic stress.

  9. Insomnia and risk of dementia in older adults: Systematic review and meta-analysis.

    Science.gov (United States)

    de Almondes, Katie Moraes; Costa, Mônica Vieira; Malloy-Diniz, Leandro Fernandes; Diniz, Breno Satler

    2016-06-01

    There are cross-sectional evidences of an association between sleep disorders and cognitive impairment on older adults. However, there are no consensus by means of longitudinal studies data on the increased risk of developing dementia related to insomnia. We conduct a systematic review and meta-analysis to evaluate the risk of incident all-cause dementia in individuals with insomnia in population-based prospective cohort studies. Five studies of 5.242 retrieved references were included in the meta-analysis. We used the generic inverse variance method with a random effects model to calculate the pooled risk of dementia in older adults with insomnia. We assessed heterogeneity in the meta-analysis by means of the Q-test and I2 index. Study quality was assessed with the Newcastle-Ottawa Scale The results showed that Insomnia was associated with a significant risk of all-cause dementia (RR = 1.53 CI95% (1.07-2.18), z = 2.36, p = 0.02). There was evidence for significant heterogeneity in the analysis (q-value = 2.4, p Insomnia is associated with an increased risk for dementia. This results provide evidences that future studies should investigate dementia prevention among elderly individuals through screening and proper management of insomnia. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Hypothyroidism as a risk factor for open angle glaucoma: A systematic review and meta-analysis

    Science.gov (United States)

    Liu, Yue; Zheng, Guangying

    2017-01-01

    Purpose The relationship between hypothyroidism and primary open angle glaucoma (POAG) has attracted intense interest recently, but the reported results have been controversial. This meta-analysis was carried out to determine the association between hypothyroidism and POAG. Methods The literature was identified from three databases (Web of Science, Embase, and PubMed). The meta-analyses were performed using random-effects models, with results reported as adjusted odds ratios (ORs) with 95% confidence intervals (CI 95%). Results A total of 11 studies meeting the inclusion criteria were included in the final meta-analysis. The pooled OR based on 11 risk estimates showed a statistically significant increased risk of POAG prevalence among individuals with hypothyroidism (OR = 1.64, 95% CI = 1.27–2.13). Substantial heterogeneity among these studies was detected (P hypothyroidism and POAG, which was not observed in cross-sectional studies. There was no significant publication bias in this study. Conclusions The findings of this meta-analysis indicate that individuals with hypothyroidism have an increased risk of developing POAG. PMID:29069095

  11. Systematic review and meta-analysis of the association between psoriasis and metabolic syndrome.

    Science.gov (United States)

    Rodríguez-Zúñiga, Milton José Max; García-Perdomo, Herney Andrés

    2017-10-01

    Several studies have shown a relationship between psoriasis and metabolic syndrome (MS), but no meta-analysis has been restricted to studies that adjusted for confounders. To determine the association between psoriasis and MS. A systematic review and meta-analysis of observational studies on psoriasis and MS in adults was performed from MEDLINE, Scopus, SciELO, Google Scholar, Science Direct, and LILACS from inception to January 2016. We performed a random effects model meta-analysis for those studies reporting adjusted odds ratios (ORs) with 95% confidence intervals (CIs). The subgroup analysis was related to geographic location, diagnosis criteria and risk of bias. In all, 14 papers including a total of 25,042 patients with psoriasis were analyzed. We found that MS was present in 31.4% of patients with psoriasis (OR, 1.42; 95% CI, 1.28-1.65). Middle Eastern studies (in Israel, Turkey, and Lebanon) (OR, 1.76, 95% CI, 0.86-2.67) reported a greater risk for MS than European studies (in Germany, Italy, the United Kingdom, Norway, and Denmark) (OR, 1.40; 95% CI, 1.25-1.55). Few adjusted studies existed, and there was inconsistency between publications. Because of the increased risk for MS, clinicians should consider screening patients with psoriasis for metabolic risk factors. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  12. Association between developmental defects of enamel and dental caries: A systematic review and meta-analysis.

    Science.gov (United States)

    Vargas-Ferreira, F; Salas, M M S; Nascimento, G G; Tarquinio, S B C; Faggion, C M; Peres, M A; Thomson, W M; Demarco, F F

    2015-06-01

    Dental caries is the main problem oral health and it is not well established in the literature if the enamel defects are a risk factor for its development. Studies have reported a potential association between developmental defects enamel (DDE) and dental caries occurrence. We investigated the association between DDE and caries in permanent dentition of children and teenagers. A systematic review was carried out using four databases (Pubmed, Web of Science, Embase, and Science Direct), which were searched from their earliest records until December 31, 2014. Population-based studies assessing differences in dental caries experience according to the presence of enamel defects (and their types) were included. PRISMA guidelines for reporting systematic reviews were followed. Meta-analysis was performed to assess the pooled effect, and meta-regression was carried out to identify heterogeneity sources. From the 2558 initially identified papers, nine studies fulfilled all inclusion criteria after checking the titles, abstracts, references, and complete reading. Seven of them were included in the meta-analysis with random model. A positive association between enamel defects and dental caries was identified; meta-analysis showed that individuals with DDE had higher pooled odds of having dental caries experience [OR 2.21 (95% CI 1.3; 3.54)]. Meta-regression analysis demonstrated that adjustment for sociodemographic factors, countries' socioeconomic status, and bias (quality of studies) explained the high heterogeneity observed. A higher chance of dental caries should be expected among individuals with enamel defects. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Meta-Analysis of Price Elasticity for Urban Domestic Water Consumption in Iran

    Directory of Open Access Journals (Sweden)

    Mina Tajabadi

    2018-03-01

    Full Text Available Price elasticity plays a critical role in determining water tariff and its system. Many economic decision makers and researchers have estimated demand function for different cities in order to predict the associated income and price elasticity. In this research we reviewed 20 studies on urban domestic water demand function from which 63 price elasticity values were obtained. Since the price elasticity values obtained from these studies had significant statistical differences, the aim of this research is to determine the effective factors in price elasticity values as well as to analyze differences in such values using meta-analysis technique. The meta-analysis technique focuses on variation in water price elasticity results. The statistical meta-analysis technique focuses on two main objectives of publication bias or publication heterogeneity in reported results. The results indicated that publication bias is negligible while publication heterogeneity is significant. The major factors affecting price elasticity values are classified into 4 categories including theoretical, model, data and socio-geographical specifications. The result indicated that variables such as income, time-series datasets, natural logarithm function and use of stone-geary theory which is the basis for predicting many domestic water demand functions, significantly overestimate the price elasticity values. Also the geographical condition of the region, population density and use of OLS technique to estimate the demand parameters underestimates the price elasticity values.

  14. Meta-analysis in plant pathology: synthesizing research results.

    Science.gov (United States)

    Rosenberg, M S; Garrett, K A; Su, Z; Bowden, R L

    2004-09-01

    ABSTRACT Meta-analysis is a set of statistical procedures for synthesizing research results from a number of different studies. An estimate of a statistical effect, such as the difference in disease severity for plants with or without a management treatment, is collected from each study along with a measure of the variance of the estimate of the effect. Combining results from different studies will generally result in increased statistical power so that it is easier to detect small effects. Combining results from different studies may also make it possible to compare the size of the effect as a function of other predictor variables such as geographic region or pathogen species. We present a review of the basic methodology for meta-analysis. We also present an example of meta-analysis of the relationship between disease severity and yield loss for foliar wheat diseases, based on data collected from a decade of fungicide and nematicide test results.

  15. Trial Sequential Analysis in systematic reviews with meta-analysis

    DEFF Research Database (Denmark)

    Wetterslev, Jørn; Jakobsen, Janus Christian; Gluud, Christian

    2017-01-01

    . The results of the meta-analyses should relate the total number of randomised participants to the estimated required meta-analytic information size accounting for statistical diversity. When the number of participants and the corresponding number of trials in a meta-analysis are insufficient, the use......BACKGROUND: Most meta-analyses in systematic reviews, including Cochrane ones, do not have sufficient statistical power to detect or refute even large intervention effects. This is why a meta-analysis ought to be regarded as an interim analysis on its way towards a required information size...... for statistical significance when the diversity-adjusted required information size and the corresponding number of required trials for the meta-analysis have not been reached. Trial Sequential Analysis provides a frequentistic approach to control both type I and type II errors. We define the required information...

  16. A Bayesian approach to meta-analysis of plant pathology studies.

    Science.gov (United States)

    Mila, A L; Ngugi, H K

    2011-01-01

    Bayesian statistical methods are used for meta-analysis in many disciplines, including medicine, molecular biology, and engineering, but have not yet been applied for quantitative synthesis of plant pathology studies. In this paper, we illustrate the key concepts of Bayesian statistics and outline the differences between Bayesian and classical (frequentist) methods in the way parameters describing population attributes are considered. We then describe a Bayesian approach to meta-analysis and present a plant pathological example based on studies evaluating the efficacy of plant protection products that induce systemic acquired resistance for the management of fire blight of apple. In a simple random-effects model assuming a normal distribution of effect sizes and no prior information (i.e., a noninformative prior), the results of the Bayesian meta-analysis are similar to those obtained with classical methods. Implementing the same model with a Student's t distribution and a noninformative prior for the effect sizes, instead of a normal distribution, yields similar results for all but acibenzolar-S-methyl (Actigard) which was evaluated only in seven studies in this example. Whereas both the classical (P = 0.28) and the Bayesian analysis with a noninformative prior (95% credibility interval [CRI] for the log response ratio: -0.63 to 0.08) indicate a nonsignificant effect for Actigard, specifying a t distribution resulted in a significant, albeit variable, effect for this product (CRI: -0.73 to -0.10). These results confirm the sensitivity of the analytical outcome (i.e., the posterior distribution) to the choice of prior in Bayesian meta-analyses involving a limited number of studies. We review some pertinent literature on more advanced topics, including modeling of among-study heterogeneity, publication bias, analyses involving a limited number of studies, and methods for dealing with missing data, and show how these issues can be approached in a Bayesian framework

  17. Evaluation of RGP Contact Lens Fitting in Keratoconus Patients Using Hierarchical Fuzzy Model and Genetic Algorithms.

    Science.gov (United States)

    Falahati Marvast, Fatemeh; Arabalibeik, Hossein; Alipour, Fatemeh; Sheikhtaheri, Abbas; Nouri, Leila; Soozande, Mehdi; Yarmahmoodi, Masood

    2016-01-01

    Keratoconus is a progressive non-inflammatory disease of the cornea. Rigid gas permeable contact lenses (RGPs) are prescribed when the disease progresses. Contact lens fitting and assessment is very difficult in these patients and is a concern of ophthalmologists and optometrists. In this study, a hierarchical fuzzy system is used to capture the expertise of experienced ophthalmologists during the lens evaluation phase of prescription. The system is fine-tuned using genetic algorithms. Sensitivity, specificity and accuracy of the final system are 88.9%, 94.4% and 92.6% respectively.

  18. Formalizing the definition of meta-analysis in Molecular Ecology.

    Science.gov (United States)

    ArchMiller, Althea A; Bauer, Eric F; Koch, Rebecca E; Wijayawardena, Bhagya K; Anil, Ammu; Kottwitz, Jack J; Munsterman, Amelia S; Wilson, Alan E

    2015-08-01

    Meta-analysis, the statistical synthesis of pertinent literature to develop evidence-based conclusions, is relatively new to the field of molecular ecology, with the first meta-analysis published in the journal Molecular Ecology in 2003 (Slate & Phua 2003). The goal of this article is to formalize the definition of meta-analysis for the authors, editors, reviewers and readers of Molecular Ecology by completing a review of the meta-analyses previously published in this journal. We also provide a brief overview of the many components required for meta-analysis with a more specific discussion of the issues related to the field of molecular ecology, including the use and statistical considerations of Wright's FST and its related analogues as effect sizes in meta-analysis. We performed a literature review to identify articles published as 'meta-analyses' in Molecular Ecology, which were then evaluated by at least two reviewers. We specifically targeted Molecular Ecology publications because as a flagship journal in this field, meta-analyses published in Molecular Ecology have the potential to set the standard for meta-analyses in other journals. We found that while many of these reviewed articles were strong meta-analyses, others failed to follow standard meta-analytical techniques. One of these unsatisfactory meta-analyses was in fact a secondary analysis. Other studies attempted meta-analyses but lacked the fundamental statistics that are considered necessary for an effective and powerful meta-analysis. By drawing attention to the inconsistency of studies labelled as meta-analyses, we emphasize the importance of understanding the components of traditional meta-analyses to fully embrace the strengths of quantitative data synthesis in the field of molecular ecology. © 2015 John Wiley & Sons Ltd.

  19. Trial Sequential Analysis in systematic reviews with meta-analysis

    Directory of Open Access Journals (Sweden)

    Jørn Wetterslev

    2017-03-01

    Full Text Available Abstract Background Most meta-analyses in systematic reviews, including Cochrane ones, do not have sufficient statistical power to detect or refute even large intervention effects. This is why a meta-analysis ought to be regarded as an interim analysis on its way towards a required information size. The results of the meta-analyses should relate the total number of randomised participants to the estimated required meta-analytic information size accounting for statistical diversity. When the number of participants and the corresponding number of trials in a meta-analysis are insufficient, the use of the traditional 95% confidence interval or the 5% statistical significance threshold will lead to too many false positive conclusions (type I errors and too many false negative conclusions (type II errors. Methods We developed a methodology for interpreting meta-analysis results, using generally accepted, valid evidence on how to adjust thresholds for significance in randomised clinical trials when the required sample size has not been reached. Results The Lan-DeMets trial sequential monitoring boundaries in Trial Sequential Analysis offer adjusted confidence intervals and restricted thresholds for statistical significance when the diversity-adjusted required information size and the corresponding number of required trials for the meta-analysis have not been reached. Trial Sequential Analysis provides a frequentistic approach to control both type I and type II errors. We define the required information size and the corresponding number of required trials in a meta-analysis and the diversity (D2 measure of heterogeneity. We explain the reasons for using Trial Sequential Analysis of meta-analysis when the actual information size fails to reach the required information size. We present examples drawn from traditional meta-analyses using unadjusted naïve 95% confidence intervals and 5% thresholds for statistical significance. Spurious conclusions in

  20. Meta-Analysis of Correlations Among Usability Measures

    DEFF Research Database (Denmark)

    Hornbæk, Kasper Anders Søren; Effie Lai Chong, Law

    2007-01-01

    Understanding the relation between usability measures seems crucial to deepen our conception of usability and to select the right measures for usability studies. We present a meta-analysis of correlations among usability measures calculated from the raw data of 73 studies. Correlations are genera......Understanding the relation between usability measures seems crucial to deepen our conception of usability and to select the right measures for usability studies. We present a meta-analysis of correlations among usability measures calculated from the raw data of 73 studies. Correlations...

  1. A meta-analysis of cerebrovascular disease and hyperhomocysteinaemia

    DEFF Research Database (Denmark)

    Nielsen, G M; Tvedegaard, K C; Andersen, Niels Trolle

    2000-01-01

    Hyperhomocysteinaemia has been identified as a risk factor for stroke and cerebrovascular disease in several studies. To evaluate the evidence we performed a meta-analysis. We found 21 studies searching Medline from 1966-July 1999 using the key words homocysteine, homocystine and cerebrovascular...... was used. The reports on 8 cross-sectional and 4 longitudinal studies gave data on the mean and standard deviations of plasma or serum homocysteine for both cases and controls, and these studies were included in the meta-analysis. The results of the 5 excluded studies all pointed to a positive relationship...

  2. Moral responsibility and free will: A meta-analysis.

    Science.gov (United States)

    Feltz, Adam; Cova, Florian

    2014-11-01

    Fundamental beliefs about free will and moral responsibility are often thought to shape our ability to have healthy relationships with others and ourselves. Emotional reactions have also been shown to have an important and pervasive impact on judgments and behaviors. Recent research suggests that emotional reactions play a prominent role in judgments about free will, influencing judgments about determinism's relation to free will and moral responsibility. However, the extent to which affect influences these judgments is unclear. We conducted a meta-analysis to estimate the impact of affect. Our meta-analysis indicates that beliefs in free will are largely robust to emotional reactions. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Population-based meta-analysis of hydrochlorothiazide pharmacokinetics.

    Science.gov (United States)

    Van Wart, Scott A; Shoaf, Susan E; Mallikaarjun, Suresh; Mager, Donald E

    2013-12-01

    Hydrochlorothiazide (HCTZ) is a thiazide diuretic used for the treatment of hypertension and edema associated with fluid overload conditions such as congestive heart failure (CHF). A population-based meta-analysis approach in NONMEM® was used to develop a PK model to characterize the time-course of HCTZ concentrations in plasma and excretion into the urine for healthy subjects and CHF patients. Data from healthy subjects receiving 100 mg of oral HCTZ were supplemented with additional plasma concentration and urinary excretion versus time data published in the literature following administration of oral HCTZ doses ranging from 10 to 500 mg to healthy subjects or patients with renal failure, CHF or hypertension. A two-compartment model with first-order oral absorption, using a Weibull function, and first-order elimination best described HCTZ PK. Creatinine clearance (CLCR ) was a statistically significant predictor of renal clearance (CLR ). Non-renal clearance was estimated to be 2.44 l/h, CLR was 18.3 l/h and T1/2,α was 1.6 h and T1/2,β was 14.8 h for a typical individual with normal renal function (CLCR  = 120 ml/min). However, CLR was reduced to 10.5, 5.47 and 2.70 l/h in mild (CLCR  = 80 ml/min), moderate (CLCR  = 50 ml/min) and severe (CLCR  = 30 ml/min) renal impairment, respectively. Model diagnostics helped to demonstrate that the population PK model reasonably predicts the rate of urinary HCTZ excretion over time using dosing history and estimated CLCR , allowing for the convenient assessment of PK-PD relationships for HCTZ when given alone or in combination with other agents used to treat fluid overload conditions. Copyright © 2013 John Wiley & Sons, Ltd.

  4. Meta-Analysis and Advancement of Brucellosis Vaccinology.

    Directory of Open Access Journals (Sweden)

    Tatiane F Carvalho

    Full Text Available In spite of all the research effort for developing new vaccines against brucellosis, it remains unclear whether these new vaccine technologies will in fact become widely used. The goal of this study was to perform a meta-analysis to identify parameters that influence vaccine efficacy as well as a descriptive analysis on how the field of Brucella vaccinology is advancing concerning type of vaccine, improvement of protection on animal models over time, and factors that may affect protection in the mouse model.A total of 117 publications that met the criteria were selected for inclusion in this study, with a total of 782 individual experiments analyzed.Attenuated (n = 221, inactivated (n = 66 and mutant (n = 102 vaccines provided median protection index above 2, whereas subunit (n = 287, DNA (n = 68, and vectored (n = 38 vaccines provided protection indexes lower than 2. When all categories of experimental vaccines are analyzed together, the trend line clearly demonstrates that there was no improvement of the protection indexes over the past 30 years, with a low negative and non significant linear coefficient. A meta-regression model was developed including all vaccine categories (attenuated, DNA, inactivated, mutant, subunit, and vectored considering the protection index as a dependent variable and the other parameters (mouse strain, route of vaccination, number of vaccinations, use of adjuvant, challenge Brucella species as independent variables. Some of these variables influenced the expected protection index of experimental vaccines against Brucella spp. in the mouse model.In spite of the large number of publication over the past 30 years, our results indicate that there is not clear trend to improve the protective potential of these experimental vaccines.

  5. A Simple Model of the Accommodating Lens of the Human Eye

    Science.gov (United States)

    Oommen, Vinay; Kanthakumar, Praghalathan

    2014-01-01

    The human eye is often discussed as optically equivalent to a photographic camera. The iris is compared with the shutter, the pupil to the aperture, and the retina to the film, and both have lens systems to focus rays of light. Although many similarities exist, a major difference between the two systems is the mechanism involved in focusing an…

  6. Modeling of radial asymmetry in lens distortion facilitated by modern optimization techniques

    CSIR Research Space (South Africa)

    De Villiers, Johan P

    2010-01-18

    Full Text Available -centering. This paper shows that the characterization of lens distortion can be improved by over 79% compared to prevailing methods. This is achieved by using modern numerical optimization techniques such as the Leapfrog algorithm, and sensitivity-normalized parameter...

  7. Numerical modelling and hydrochemical characterisation of a fresh-water lens in the Belgian coastal plain

    Science.gov (United States)

    Vandenbohede, A.; Lebbe, L.

    2002-05-01

    The distribution of fresh and salt water in coastal aquifers is influenced by many processes. The influence of aquifer heterogeneity and human interference such as land reclamation is illustrated in the Belgian coastal plain where, around A.D. 1200, the reclamation of a tidally influenced environment was completed. The aquifer, which was filled with salt water, was thereafter freshened. The areal distribution of peat, clay, silt and sand influences the general flow and distribution of fresh and salt water along with the drainage pattern and results in the development of fresh-water lenses. The water quality in and around the fresh-water lenses below an inverted tidal channel ridge is surveyed. The hydrochemical evolution of the fresh water lens is reconstructed, pointing to cation exchange, solution of calcite and the oxidation of organic material as the major chemical reactions. The formation and evolution of the fresh water lens is modelled using a two-dimensional density-dependent solute transport model and the sensitivity of drainage and conductivities are studied. Drainage level mainly influences the depth of the fresh-water lens, whereas the time of formation is mainly influenced by conductivity. Résumé. La répartition de l'eau douce et de l'eau salée dans les aquifères littoraux est influencée par de nombreux mécanismes. L'influence de l'hétérogénéité de l'aquifère et des interférences anthropiques telles que la mise en valeur des terres est illustrée par la plaine côtière belge où, depuis l'an 1200, on a mis en valeur un environnement soumis aux marées. L'aquifère, qui contenait de l'eau salée, contient maintenant de l'eau douce. La distribution spatiale de tourbe, d'argile, de silt et de sable joue un rôle dans l'écoulement général et dans la répartition de l'eau douce et de l'eau salée le long du réseau de drainage et produit des lentilles d'eau douce. La qualité de l'eau dans et autour des lentilles d'eau douce sous une lev

  8. αA crystallin may protect against geographic atrophy-meta-analysis of cataract vs. cataract surgery for geographic atrophy and experimental studies.

    Directory of Open Access Journals (Sweden)

    Peng Zhou

    Full Text Available BACKGROUND: Cataract and geographic atrophy (GA, also called advanced "dry" age-related macular degeneration are the two major causes of visual impairment in the developed world. The association between cataract surgery and the development of GA was controversial in previous studies. METHODS/PRINCIPAL FINDINGS: We performed a meta-analysis by pooling the current evidence in literature and found that cataract is associated with an increased risk of geographic atrophy with a summary odds ratio (OR of 3.75 (95% CI: 95% CI: 1.84-7.62. However, cataract surgery is not associated with the risk of geographic atrophy (polled OR=3.23, 95% CI: 0.63-16.47. Further experiments were performed to analyze how the αA-crystallin, the major component of the lens, influences the development of GA in a mouse model. We found that theαA-crystallin mRNA and protein expression increased after oxidative stress induced by NaIO(3 in immunohistochemistry of retinal section and western blot of posterior eyecups. Both functional and histopathological evidence confirmed that GA is more severe in αA-crystallin knockout mice compared to wild-type mice. CONCLUSIONS: Therefore, αA-crystallin may protect against geographic atrophy. This study provides a better understanding of the relationship between cataract, cataract surgery, and GA.

  9. Methods for network meta-analysis of continuous outcomes using individual patient data: a case study in acupuncture for chronic pain.

    Science.gov (United States)

    Saramago, Pedro; Woods, Beth; Weatherly, Helen; Manca, Andrea; Sculpher, Mark; Khan, Kamran; Vickers, Andrew J; MacPherson, Hugh

    2016-10-06

    Network meta-analysis methods, which are an extension of the standard pair-wise synthesis framework, allow for the simultaneous comparison of multiple interventions and consideration of the entire body of evidence in a single statistical model. There are well-established advantages to using individual patient data to perform network meta-analysis and methods for network meta-analysis of individual patient data have already been developed for dichotomous and time-to-event data. This paper describes appropriate methods for the network meta-analysis of individual patient data on continuous outcomes. This paper introduces and describes network meta-analysis of individual patient data models for continuous outcomes using the analysis of covariance framework. Comparisons are made between this approach and change score and final score only approaches, which are frequently used and have been proposed in the methodological literature. A motivating example on the effectiveness of acupuncture for chronic pain is used to demonstrate the methods. Individual patient data on 28 randomised controlled trials were synthesised. Consistency of endpoints across the evidence base was obtained through standardisation and mapping exercises. Individual patient data availability avoided the use of non-baseline-adjusted models, allowing instead for analysis of covariance models to be applied and thus improving the precision of treatment effect estimates while adjusting for baseline imbalance. The network meta-analysis of individual patient data using the analysis of covariance approach is advocated to be the most appropriate modelling approach for network meta-analysis of continuous outcomes, particularly in the presence of baseline imbalance. Further methods developments are required to address the challenge of analysing aggregate level data in the presence of baseline imbalance.

  10. The dilemma of heterogeneity tests in meta-analysis: a challenge from a simulation study.

    Directory of Open Access Journals (Sweden)

    Shi-jun Li

    Full Text Available After several decades' development, meta-analysis has become the pillar of evidence-based medicine. However, heterogeneity is still the threat to the validity and quality of such studies. Currently, Q and its descendant I(2 (I square tests are widely used as the tools for heterogeneity evaluation. The core mission of this kind of test is to identify data sets from similar populations and exclude those are from different populations. Although Q and I(2 are used as the default tool for heterogeneity testing, the work we present here demonstrates that the robustness of these two tools is questionable.We simulated a strictly normalized population S. The simulation successfully represents randomized control trial data sets, which fits perfectly with the theoretical distribution (experimental group: p = 0.37, control group: p = 0.88. And we randomly generate research samples Si that fits the population with tiny distributions. In short, these data sets are perfect and can be seen as completely homogeneous data from the exactly same population. If Q and I(2 are truly robust tools, the Q and I(2 testing results on our simulated data sets should not be positive. We then synthesized these trials by using fixed model. Pooled results indicated that the mean difference (MD corresponds highly with the true values, and the 95% confidence interval (CI is narrow. But, when the number of trials and sample size of trials enrolled in the meta-analysis are substantially increased; the Q and I(2 values also increase steadily. This result indicates that I(2 and Q are only suitable for testing heterogeneity amongst small sample size trials, and are not adoptable when the sample sizes and the number of trials increase substantially.Every day, meta-analysis studies which contain flawed data analysis are emerging and passed on to clinical practitioners as "updated evidence". Using this kind of evidence that contain heterogeneous data sets leads to wrong conclusion, makes

  11. Chronic subdural hematoma: a systematic review and meta-analysis of surgical procedures.

    Science.gov (United States)

    Liu, Weiming; Bakker, Nicolaas A; Groen, Rob J M

    2014-09-01

    In this paper the authors systematically evaluate the results of different surgical procedures for chronic subdural hematoma (CSDH). The MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and other databases were scrutinized according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement, after which only randomized controlled trials (RCTs) and quasi-RCTs were included. At least 2 different neurosurgical procedures in the management of chronic subdural hematoma (CSDH) had to be evaluated. Included studies were assessed for the risk of bias. Recurrence rates, complications, and outcome including mortality were taken as outcome measures. Statistical heterogeneity in each meta-analysis was assessed using the T(2) (tau-squared), I(2), and chi-square tests. The DerSimonian-Laird method was used to calculate the summary estimates using the fixed-effect model in meta-analysis. Of the 297 studies identified, 19 RCTs were included. Of them, 7 studies evaluated the use of postoperative drainage, of which the meta-analysis showed a pooled OR of 0.36 (95% CI 0.21-0.60; p < 0.001) in favor of drainage. Four studies compared twist drill and bur hole procedures. No significant differences between the 2 methods were present, but heterogeneity was considered to be significant. Three studies directly compared the use of irrigation before drainage. A fixed-effects meta-analysis showed a pooled OR of 0.49 (95% CI 0.21-1.14; p = 0.10) in favor of irrigation. Two studies evaluated postoperative posture. The available data did not reveal a significant advantage in favor of the postoperative supine posture. Regarding positioning of the catheter used for drainage, it was shown that a frontal catheter led to a better outcome. One study compared duration of drainage, showing that 48 hours of drainage was as effective as 96 hours of drainage. Postoperative drainage has the advantage of reducing recurrence without increasing complications

  12. Network meta-analysis of (individual patient) time to event data alongside (aggregate) count data.

    Science.gov (United States)

    Saramago, Pedro; Chuang, Ling-Hsiang; Soares, Marta O

    2014-09-10

    Network meta-analysis methods extend the standard pair-wise framework to allow simultaneous comparison of multiple interventions in a single statistical model. Despite published work on network meta-analysis mainly focussing on the synthesis of aggregate data, methods have been developed that allow the use of individual patient-level data specifically when outcomes are dichotomous or continuous. This paper focuses on the synthesis of individual patient-level and summary time to event data, motivated by a real data example looking at the effectiveness of high compression treatments on the healing of venous leg ulcers. This paper introduces a novel network meta-analysis modelling approach that allows individual patient-level (time to event with censoring) and summary-level data (event count for a given follow-up time) to be synthesised jointly by assuming an underlying, common, distribution of time to healing. Alternative model assumptions were tested within the motivating example. Model fit and adequacy measures were used to compare and select models. Due to the availability of individual patient-level data in our example we were able to use a Weibull distribution to describe time to healing; otherwise, we would have been limited to specifying a uniparametric distribution. Absolute effectiveness estimates were more sensitive than relative effectiveness estimates to a range of alternative specifications for the model. The synthesis of time to event data considering individual patient-level data provides modelling flexibility, and can be particularly important when absolute effectiveness estimates, and not just relative effect estimates, are of interest.

  13. A Meta-Analysis of Global Urban Land Expansion

    Science.gov (United States)

    Seto, Karen C.; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K.

    2011-01-01

    The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km2 from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km2 and 12,568,000 km2, with an estimate of 1,527,000 km2 more likely. PMID:21876770

  14. A meta-analysis of global urban land expansion.

    Science.gov (United States)

    Seto, Karen C; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K

    2011-01-01

    The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km(2) from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km(2) and 12,568,000 km(2), with an estimate of 1,527,000 km(2) more likely.

  15. A Meta-Analysis of Extensive Reading Research

    Science.gov (United States)

    Nakanishi, Takayuki

    2015-01-01

    The purposes of this study were to investigate the overall effectiveness of extensive reading, whether learners' age impacts learning, and whether the length of time second language learners engage in extensive reading influences test scores. The author conducted a meta-analysis to answer research questions and to identify future research…

  16. Effectiveness of Secondary Pregnancy Prevention Programs: A Meta-Analysis

    Science.gov (United States)

    Corcoran, Jacqueline; Pillai, Vijayan K.

    2007-01-01

    Because subsequent pregnancy in teen parents often worsens the impact of adolescent parenting; therefore, a common goal of teenage parent programs has been to reduce repeat pregnancy. To examine the impact of this goal, a meta-analysis was conducted on 16 control-comparison group studies that evaluated the effect of teenage pregnancy and parenting…

  17. The Categorical Perception Deficit in Dyslexia: A Meta-Analysis

    Science.gov (United States)

    Noordenbos, Mark W.; Serniclaes, Willy

    2015-01-01

    Speech perception in dyslexia is characterized by a categorical perception (CP) deficit, demonstrated by weaker discrimination of acoustic differences between phonemic categories in conjunction with better discrimination of acoustic differences within phonemic categories. We performed a meta-analysis of studies that examined the reliability of the…

  18. Moral development and recidivism: A meta-analysis.

    NARCIS (Netherlands)

    van Vugt, E.S.; Gibbs, J.; Stams, G.J.; Bijleveld, C.C.J.H.; van der Laan, P.H.; Hendriks, J.

    2011-01-01

    A meta-analysis of 19 studies (N = 15,992 offenders) showed a significant inverse relation between more mature moral development and recidivism. Moderator analyses revealed a larger effect size for moral cognition (r =.20) than for moral emotion (r =.11). Effect sizes for production measures (r

  19. Moral development and recidivism: a meta-analysis

    NARCIS (Netherlands)

    van Vugt, E.; Gibbs, J.; Stams, G.J.; Bijleveld, C.; Hendriks, J.; van der Laan, P.

    2011-01-01

    A meta-analysis of 19 studies (N = 15,992 offenders) showed a significant inverse relation between more mature moral development and recidivism. Moderator analyses revealed a larger effect size for moral cognition (r = .20) than for moral emotion (r = .11). Effect sizes for production measures (r =

  20. A Meta-Analysis of Outdoor Adventure Programming with Adolescents.

    Science.gov (United States)

    Cason, Dana; Gillis, H. L. Lee

    1994-01-01

    Meta-analysis of 143 effect sizes in 43 studies of adventure programming for adolescents found an overall effect size of 0.31. Summary effect sizes of outcome categories differed significantly among categories, however. Effect size was related to program length and participant age but not to delinquent status. Discusses the lack of pertinent…

  1. Updated Meta-Analysis of Learner Control within Educational Technology

    Science.gov (United States)

    Karich, Abbey C.; Burns, Matthew K.; Maki, Kathrin E.

    2014-01-01

    Giving a student control over their learning has theoretical and intuitive appeal, but its effects are neither powerful nor consistent in the empirical literature base. This meta-analysis updated previous meta-analytic research by Niemiec, Sikorski, and Walberg by studying the overall effectiveness of providing learner control within educational…

  2. Effectiveness of Conceptual Change Texts: A Meta Analysis

    Science.gov (United States)

    Armagan, Fulya Öner; Keskin, Melike Özer; Akin, Beril Salman

    2017-01-01

    The purpose of this study was to determine the overall effectiveness of conceptual change texts (CCTs) on academic achievement and to find out if effectiveness was related to some characteristics of the study. It followed up a Meta-analysis research approach. 42 published and unpublished studies, published between 1995 and 2010, and 42 experiment…

  3. Creativity and Academic Achievement: A Meta-Analysis

    Science.gov (United States)

    Gajda, Aleksandra; Karwowski, Maciej; Beghetto, Ronald A.

    2017-01-01

    This article reports on a meta-analysis of 120 studies (total N = 52,578; 782 effects) examining the relationship between creativity and academic achievement in research conducted since the 1960s. Average correlation between creativity and academic achievement was r = 0.22, 95% CI [0.19, 0.24]. An analysis of moderators revealed that this…

  4. Macroeconomics of natural disasters : Meta-analysis and policy options

    NARCIS (Netherlands)

    P.A.G. van Bergeijk (Peter); S. Lazzaroni (Sara)

    2013-01-01

    textabstractWe use the case of the impact of natural disasters to analyse strengths and weaknesses of meta-analysis in an emerging research field. Macroeconomists have published on this issue since 2002 (we identified 22 studies to date). The results of the studies are contradictory and

  5. Visuo-Spatial Performance in Autism: A Meta-Analysis

    Science.gov (United States)

    Muth, Anne; Hönekopp, Johannes; Falter, Christine M.

    2014-01-01

    Visuo-spatial skills are believed to be enhanced in autism spectrum disorders (ASDs). This meta-analysis tests the current state of evidence for Figure Disembedding, Block Design, Mental Rotation and Navon tasks in ASD and neurotypicals. Block Design (d = 0.32) and Figure Disembedding (d = 0.26) showed superior performance for ASD with large…

  6. Meta-analysis of graduated driver licensing laws.

    Science.gov (United States)

    2015-11-01

    The objective of the present study was to assess the effectiveness of GDL programs for reducing total, injury, and fatal crashes among drivers 15 to 20 years old by conducting a meta-analysis of GDL research since 2001 that evaluated the effectivenes...

  7. Multivariate Meta-Analysis Using Individual Participant Data

    Science.gov (United States)

    Riley, R. D.; Price, M. J.; Jackson, D.; Wardle, M.; Gueyffier, F.; Wang, J.; Staessen, J. A.; White, I. R.

    2015-01-01

    When combining results across related studies, a multivariate meta-analysis allows the joint synthesis of correlated effect estimates from multiple outcomes. Joint synthesis can improve efficiency over separate univariate syntheses, may reduce selective outcome reporting biases, and enables joint inferences across the outcomes. A common issue is…

  8. Meta-analysis of landscape conservation plan evaluations

    Science.gov (United States)

    Michaela Foster; M. Nils Peterson; Frederick Cubbage; Gerard McMahon

    2016-01-01

    The number of studies evaluating the quality and content of many types of plans have grown in recent decades. Natural resource conservation plans have been included in some of these plan evaluation studies; however, no meta-analysis of natural resource planning literature has been conducted. This focus is needed because natural resource conservation planning differs...

  9. Does College Teach Critical Thinking? A Meta-Analysis

    Science.gov (United States)

    Huber, Christopher R.; Kuncel, Nathan R.

    2016-01-01

    Educators view critical thinking as an essential skill, yet it remains unclear how effectively it is being taught in college. This meta-analysis synthesizes research on gains in critical thinking skills and attitudinal dispositions over various time frames in college. The results suggest that both critical thinking skills and dispositions improve…

  10. A Meta-Analysis: Acoustic Measurement of Roughness and Breathiness

    Science.gov (United States)

    v. Latoszek, Ben Barsties; Maryn, Youri; Gerrits, Ellen; De Bodt, Marc

    2018-01-01

    Purpose: Over the last 5 decades, many acoustic measures have been created to measure roughness and breathiness. The aim of this study is to present a meta-analysis of correlation coefficients (r) between auditory-perceptual judgment of roughness and breathiness and various acoustic measures in both sustained vowels and continuous speech. Method:…

  11. [The meta-analysis of data from individual patients].

    NARCIS (Netherlands)

    Rovers, M.M.; Reitsma, J.B.

    2012-01-01

    - An IPD (Individual Participant Data) meta-analysis requires collecting original individual patient data and calculating an estimated effect based on these data.- The use of individual patient data has various advantages: the original data and the results of published analyses are verified,

  12. The Psychological Effects of Meditation: A Meta-Analysis

    Science.gov (United States)

    Sedlmeier, Peter; Eberth, Juliane; Schwarz, Marcus; Zimmermann, Doreen; Haarig, Frederik; Jaeger, Sonia; Kunze, Sonja

    2012-01-01

    In this meta-analysis, we give a comprehensive overview of the effects of meditation on psychological variables that can be extracted from empirical studies, concentrating on the effects of meditation on nonclinical groups of adult meditators. Mostly because of methodological problems, almost 3/4 of an initially identified 595 studies had to be…

  13. The Economic Value of Mangroves: A Meta-Analysis

    Science.gov (United States)

    Marwa Salem; D. Evan Mercer

    2012-01-01

    This paper presents a synthesis of the mangrove ecosystem valuation literature through a meta-regression analysis. The main contribution of this study is that it is the first meta-analysis focusing solely on mangrove forests, whereas previous studies have included different types of wetlands. The number of studies included in the regression analysis is 44 for a total...

  14. Insight in psychosis and neuropsychological function - Meta-analysis

    NARCIS (Netherlands)

    Aleman, Andre; Agrawal, Niruj; Morgan, Kevin D.; David, Anthony S.

    Background One factor contributing to impaired awareness of illness (poor insight) in psychotic disorders may be neurocognitive deficits. Method A systematic review and meta-analysis were conducted after data extraction. Following an overall analysis, in which measures of different cognitive domains

  15. Drivers of Wetland Conversion: a Global Meta-Analysis

    NARCIS (Netherlands)

    van Asselen, S.; Verburg, P.H.; Vermaat, J.E.; Janse, J.

    2013-01-01

    Meta-analysis of case studies has become an important tool for synthesizing case study findings in land change. Meta-analyses of deforestation, urbanization, desertification and change in shifting cultivation systems have been published. This present study adds to this literature, with an analysis

  16. Lead and Conduct Problems: A Meta-Analysis

    Science.gov (United States)

    Marcus, David K.; Fulton, Jessica J.; Clarke, Erin J.

    2010-01-01

    This meta-analysis examined the association between conduct problems and lead exposure. Nineteen studies on 8,561 children and adolescents were included. The average "r" across all 19 studies was 0.19 (p less than 0.001), which is considered a medium effect size. Studies that assessed lead exposure using hair element analysis yielded…

  17. A meta-analysis of electroconvulsive therapy efficacy in depression

    NARCIS (Netherlands)

    Kho, King Han; van Vreeswijk, Michiel Floris; Simpson, Steve; Zwinderman, Aeilko H.

    2003-01-01

    Recently published controlled studies comparing electroconvulsive therapy (ECT) with other treatments for depression offer the opportunity to perform a meta-analysis of ECT in depression. Fifteen studies were identified which fulfilled the inclusion criteria. From these controlled trials, 20 effect

  18. The Construct Validity of Language Aptitude: A Meta-Analysis

    Science.gov (United States)

    Li, Shaofeng

    2016-01-01

    A meta-analysis was conducted to examine the construct validity of language aptitude by synthesizing the existing research that has been accumulated over the past five decades. The study aimed to provide a thorough understanding of the construct by aggregating the data reported in the primary research on its correlations with other individual…

  19. Psychological treatment of generalized anxiety disorder: A meta-analysis.

    NARCIS (Netherlands)

    Cuijpers, P.; Sijbrandij, M.; Koole, S.L.; Huibers, M.J.H.; Berking, M.; Andersson, G.

    2014-01-01

    Recent years have seen a near-doubling of the number of studies examining the effects of psychotherapies for generalized anxiety disorder (GAD) in adults. The present article integrates this new evidence with the older literature through a quantitative meta-analysis. A total of 41 studies (with 2132

  20. A Meta-analysis of School Effectiveness Studies

    NARCIS (Netherlands)

    Scheerens, Jaap; Witziers, Bob; Steen, Rien

    2013-01-01

    A meta-analysis was carried out on the basis of 155 research studies on school effectiveness, comprising a total of 1.211 associations between school effectiveness enhancing factors and student outcome variables. The original studies were carried out between 1984 and 2005. The school effectiveness

  1. ADDIS : an automated way to do network meta-analysis

    NARCIS (Netherlands)

    Zhao, Jing; van Valkenhoef, Gert; de Brock, E.O.; Hillege, Hans

    2012-01-01

    In evidence-based medicine, meta-analysis is an important statistical technique for combining the findings from independent clinical trials which have attempted to answer similar questions about treatment's clinical eectiveness [1]. Normally, such meta-analyses are pair-wise treatment comparisons,

  2. The Relationship Between Parenting and Delinquency: A Meta-analysis

    NARCIS (Netherlands)

    Hoeve, M.; Dubas, J.S.; Eichelsheim, V.I.; Laan, P.H. van der; Smeenk, W.H.; Gerris, J.R.M.

    2009-01-01

    This meta-analysis of 161 published and unpublished manuscripts was conducted to determine whether the association between parenting and delinquency exists and what the magnitude of this linkage is. The strongest links were found for parental monitoring, psychological control, and negative aspects

  3. The relationship between parenting and delinquency: A meta-analysis

    NARCIS (Netherlands)

    Hoeve, M.; Dubas, J.S.; Eichelsheim, V.I.; van der Laan, P.H.; Smeenk, W.; Gerris, J.R.M.

    2009-01-01

    This meta-analysis of 161 published and unpublished manuscripts was conducted to determine whether the association between parenting and delinquency exists and what the magnitude of this linkage is. The strongest links were found for parental monitoring, psychological control, and negative aspects

  4. Why Is Family Firms' Internationalization Unique? : A Meta-Analysis

    NARCIS (Netherlands)

    Arregle, Jean-Luc; Duran, Patricio; Hitt, Michael A.; van Essen, M.

    Despite its importance, there is no clear understanding of the uniqueness of family firms' internationalization. This article sheds new light on this issue with a meta-analysis of 76 studies covering 41 countries. We show that the considerable study and cross-country differences in the relationship

  5. Meta-analysis of differentially expressed genes in ankylosing spondylitis.

    Science.gov (United States)

    Lee, Y H; Song, G G

    2015-05-18

    The purpose of this study was to identify differentially expressed (DE) genes and biological processes associated with changes in gene expression in ankylosing spondylitis (AS). We performed a meta-analysis using the integrative meta-analysis of expression data program on publicly available microarray AS Gene Expression Omnibus (GEO) datasets. We performed Gene Ontology (GO) enrichment analyses and pathway analysis using the Kyoto Encyclopedia of Genes and Genomes. Four GEO datasets, including 31 patients with AS and 39 controls, were available for the meta-analysis. We identified 65 genes across the studies that were consistently DE in patients with AS vs controls (23 upregulated and 42 downregulated). The upregulated gene with the largest effect size (ES; -1.2628, P = 0.020951) was integral membrane protein 2A (ITM2A), which is expressed by CD4+ T cells and plays a role in activation of T cells. The downregulated gene with the largest ES (1.2299, P = 0.040075) was mitochondrial ribosomal protein S11 (MRPS11). The most significant GO enrichment was in the respiratory electron transport chain category (P = 1.67 x 10-9). Therefore, our meta-analysis identified genes that were consistently DE as well as biological pathways associated with gene expression changes in AS.

  6. Contemporary management of frontal sinus mucoceles: a meta-analysis.

    Science.gov (United States)

    Courson, Andy M; Stankiewicz, James A; Lal, Devyani

    2014-02-01

    To analyze trends in the surgical management of frontal and fronto-ethmoid mucoceles through meta-analysis. Meta-analysis and case series. A systematic literature review on surgical management of frontal and fronto-ethmoid mucoceles was conducted. Studies were divided into historical (1975-2001) and contemporary (2002-2012) groups. A meta-analysis of these studies was performed. The historical and contemporary cohorts were compared (surgical approach, recurrence, and complications). To study evolution in surgical management, a senior surgeon's experience over 28 years was analyzed separately. Thirty-one studies were included for meta-analysis. The historical cohort included 425 mucoceles from 11 studies. The contemporary cohort included 542 mucoceles from 20 studies. More endoscopic techniques were used in the contemporary versus historical cohort (53.9% vs. 24.7%; P = contemporary). In the historical cohort, higher recurrence was noted in the external group (P = 0.03). Results from endoscopic and open approaches are comparable. Although endoscopic techniques are being increasingly adopted, comparison with our series shows that more cases could potentially be treated endoscopically. Frequent use of open approaches may reflect efficacy, or perhaps lack of expertise and equipment required for endoscopic management. Most contemporary authors favor endoscopic management, limiting open approaches for specific indications (unfavorable anatomy, lateral disease, and scarring). N/A. Copyright © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  7. The Psychophysiology of Posttraumatic Stress Disorder: A Meta-Analysis

    Science.gov (United States)

    Pole, Nnamdi

    2007-01-01

    This meta-analysis of 58 resting baseline studies, 25 startle studies, 17 standardized trauma cue studies, and 22 idiographic trauma cue studies compared adults with and without posttraumatic stress disorder (PTSD) on psychophysiological variables: facial electromyography (EMG), heart rate (HR), skin conductance (SC), and blood pressure.…

  8. Risk factors for ectopic pregnancy: a meta-analysis

    NARCIS (Netherlands)

    Ankum, W. M.; Mol, B. W.; van der Veen, F.; Bossuyt, P. M.

    1996-01-01

    OBJECTIVE: To review current knowledge on the risk of ectopic pregnancy (EP), with the exception of contraceptive methods. DESIGN: Meta-analysis. SETTING: Case control and cohort studies published between 1978 and 1994 in English, French, German, or Dutch, retrieved by Medline search, crossover

  9. Predictors of efficacy in depression prevention programmes. Meta-analysis.

    NARCIS (Netherlands)

    Jané Llopis, E.; Hosman, C.M.H.; Jenkins, R.B.; Anderson, P.D.

    2003-01-01

    BACKGROUND: Worldwide, 340 million people are affected by depression, with high comorbid, social and economic costs. AIMS: To identify potential predictors of effect in prevention programmes. METHOD: A meta-analysis was made of 69 programmes to reduce depression or depressive symptoms. RESULTS: The

  10. Clothiapine for acute psychotic illness: a meta-analysis

    African Journals Online (AJOL)

    QuickSilver

    12. Clothiapine for acute psychotic illness: a meta-analysis. Introduction. Acute psychosis requires psychological and pharmacological treatment and, when a risk of self-harm or harm to others is present, the need for treatment can become urgent. Ideally, the drug(s) used in urgent treatment of acute psychosis should have.

  11. Meta-analysis of DNA methylation biomarkers in hepatocellular carcinoma.

    Science.gov (United States)

    Zhang, Cheng; Li, Jinyun; Huang, Tao; Duan, Shiwei; Dai, Dongjun; Jiang, Danjie; Sui, Xinbing; Li, Da; Chen, Yidan; Ding, Fei; Huang, Changxin; Chen, Gongying; Wang, Kaifeng

    2016-12-06

    DNA methylation is an epigenetic mechanism in the pathogenesis of hepatocellular carcinoma (HCC). Here, we conducted a systematic meta-analysis to evaluate the contribution of DNA methylation to the risk of HCC. A total of 2109 publications were initially retrieved from PubMed, Web of Science, Cochrane Library, Embase, CNKI and Wanfang literature database. After a four-step filtration, we harvested 144 case-control articles in the meta-analysis. Our results revealed that 24 genes (carcinoma tissues vs adjacent tissues), 17 genes (carcinoma tissues vs normal tissues) and six genes (carcinoma serums vs normal serums) were significantly hypermethylated in HCC. Subgroup meta-analysis by geographical populations showed that six genes (carcinoma tissues vs adjacent tissues) and four genes (carcinoma tissues vs normal tissues) were significantly hypermethylated in HCC. Our meta-analysis identified the correlations between a number of aberrant methylated genes (p16, RASSF1A, GSTP1, p14, CDH1, APC, RUNX3, SOCS1, p15, MGMT, SFRP1, WIF1, PRDM2, DAPK1, RARβ, hMLH1, p73, DLC1, p53, SPINT2, OPCML and WT1) and HCC. Aberrant DNA methylation might become useful biomarkers for the prediction and diagnosis of HCC.

  12. Digital Simulation-Based Training: A Meta-Analysis

    Science.gov (United States)

    Gegenfurtner, Andreas; Quesada-Pallarès, Carla; Knogler, Maximilian

    2014-01-01

    This study examines how design characteristics in digital simulation-based learning environments moderate self-efficacy and transfer of learning. Drawing on social cognitive theory and the cognitive theory of multimedia learning, the meta-analysis psychometrically cumulated k?=?15 studies of 25 years of research with a total sample size of…

  13. A Meta-Analysis on Unconscious Thought Effects

    NARCIS (Netherlands)

    Strick, M.A.; Dijksterhuis, A.J.; Bos, M.W.; Sjoerdsma, A.; Baaren, R.B. van; Nordgren, L.F.

    2011-01-01

    A meta-analysis was performed on the unconscious thought effect (UTE). All available published and unpublished data on unconscious thought were included. Our aims were to provide a statistically robust estimate of the effect size of the UTE, to identify significant moderators, and to

  14. and risk of Down's syndrome child: meta-analysis

    Indian Academy of Sciences (India)

    syndrome child: meta-analysis. AMANDEEP KAUR and ANUPAM KAUR. ∗. Department of Human Genetics, Guru Nanak Dev University, Amritsar 143 005, India. Abstract. Methylenetetrahydrofolate reductase (MTHFR) is the most important gene that participates in folate metabolism. Presence of valine instead of alanine at ...

  15. Impact of Instructional Decisions on the Effectiveness of Cooperative Learning in Chemistry through Meta-Analysis

    Science.gov (United States)

    Apugliese, Andrew; Lewis, Scott E.

    2017-01-01

    Meta-analysis can provide a robust description of the impact of educational reforms and also offer an opportunity to explore the conditions where such reforms are more or less effective. This article describes a meta-analysis on the impact of cooperative learning on students' chemistry understanding. Modifiers in the meta-analysis are purposefully…

  16. Association between interleukin 1 receptor antagonist gene 86-bp VNTR polymorphism and sepsis: a meta-analysis.

    Science.gov (United States)

    Fang, Fang; Pan, Jian; Li, Yiping; Xu, Lixiao; Su, Guanghao; Li, Gang; Wang, Jian

    2015-01-01

    Many studies have focused on the relationship between interleukin 1 receptor antagonist (IL1RN) gene 86-bp VNTR polymorphism and sepsis, but the results remain inconsistent. Thus, a meta-analysis was carried out to derive a more precise estimation of the association between IL1RN 86-bp VNTR polymorphism and risk of sepsis and sepsis-related mortality. Relevant publications were searched in several widely used databases and six eligible studies were included in the meta-analysis. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between IL1RN 86-bp VNTR polymorphism and risk of sepsis and sepsis-related mortality. Significant associations between IL1RN 86-bp VNTR polymorphism and sepsis risk were observed in both overall meta-analysis for L2 versus 22 (OR=0.75, 95% CI=0.59-0.94) and severe sepsis subgroup for LL+L2 versus 22 (OR=0.67, 95% CI=0.47-0.93). L stands for long alleles containing three to six repeats; 2 stands for short allele containing two repeats. However, no significant sepsis mortality variation was detected for all genetic models. According to the results of our meta-analysis, the IL1RN 86-bp VNTR polymorphism probably associates with sepsis risk but not with sepsis-related mortality. Copyright © 2014. Published by Elsevier Inc.

  17. Efficacy and safety of sublingual immunotherapy for allergic rhinitis in pediatric patients: A meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Feng, Bohai; Wu, Jueting; Chen, Bobei; Xiang, Haijie; Chen, Ruru; Li, Bangliang; Chen, Si

    2017-01-01

    Allergic rhinitis (AR) has become a global health problem that constantly affects a large part of the general population, especially children. Sublingual allergen immunotherapy (SLIT) has been used extensively for pediatric AR, although its efficacy and safety are often questioned. In this meta-analysis of randomized controlled trials (RCT), we evaluated the use of SLIT for pediatric AR. A number of medical literature data bases were searched through January 2016 to identify RCTs that examined the use of SLIT for pediatric AR and that assessed clinical outcomes related to efficacy. Descriptive and quantitative information was abstracted. Standardized mean differences (SMD) were calculated by using fixed- and random-effects models. Subgroup analyses were performed. Heterogeneity was assessed by using the I2 metric. A network meta-analysis was used to estimate SMDs between two SLIT protocols for pediatric seasonal AR. All data were extracted from publications or received from the authors. Twenty-six studies were eligible for inclusion in the meta-analysis of rhinitis or rhinoconjunctivitis symptom scores, and 19 studies were eligible for the meta-analysis of medication scores. Descriptive and quantitative data were extracted. SLIT differed significantly from placebo in terms of symptom scores (SMD -0.55 [95% confidence interval {CI}, -0.86 to -0.25]; p = 0.0003, I2 = 90%) and medication scores (SMD -0.67 [95% CI, -0.96 to -0.38]; p pediatric patients. Moreover, the safety of SLIT needs to be confirmed in RCTs with larger samples.

  18. Association between fat mass- and obesity-associated (FTO gene polymorphism and polycystic ovary syndrome: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Xianli Cai

    Full Text Available Many studies have investigated the relationship between FTO gene polymorphism and polycystic ovary syndrome (PCOS susceptibility but revealed mixed results. In this study, we aimed to perform a meta-analysis to clarify this association.Published literature from PubMed, Embase and CNKI was retrieved. Meta-analysis was performed to calculate pooled odds ratio (OR with 95% confidence interval (CI using the random- or fix- effects model.A total of 5 studies (4778 cases and 4272 controls were included in our meta-analysis. The results suggested that FTO rs9939609 polymorphism (or its proxy was marginally associated with PCOS risk after adjustment for body mass index (BMI (OR = 1.26; 95%CI: 1.02-1.55. However, the marginal association was not stable after sensitivity analysis. In the subgroup analysis by ethnicity, the association was significant in East Asians (OR = 1.43, 95%CI = 1.30-1.59 but not in Caucasians (OR = 1.04, 95%CI = 0.85-1.29.Our present meta-analysis indicated that FTO rs9939609 polymorphism (or its proxy might not be associated with risk of PCOS in overall population. However, in East Asians, there might be a direct association between FTO variant and PCOS risk, which is independent of BMI (adiposity.

  19. Increased risk of high grade cervical squamous intraepithelial lesions in systemic lupus erythematosus: A meta-analysis of the literature.

    Science.gov (United States)

    Zard, Emilie; Arnaud, Laurent; Mathian, Alexis; Chakhtoura, Zeina; Hie, Miguel; Touraine, Philippe; Heard, Isabelle; Amoura, Zahir

    2014-07-01

    Conflicting data have been published regarding the risk of cervical lesions among women with systemic lupus erythematosus (SLE). We systematically reviewed the evidence for an association of SLE with cervical precancerous lesions (high-grade squamous intraepithelial lesions, HSIL), and performed a meta-analysis to determine the risk of HSIL in SLE patients. Observational studies identified up to February 2013 from the Medline, Embase and Cochrane databases were selected if they assessed the prevalence of HSIL in female SLE patients versus healthy female controls and included in a meta-analysis with pooled effect estimates obtained using a random-effects model. Of 235 citations retrieved, 7 studies met inclusion criteria. The pooled odds ratio for the risk of HSIL in SLE patients (n=416) versus female controls (n=11,408) was 8.66 (95% CI: 3.75-20.00), without significant heterogeneity across studies. Cumulative meta-analysis according to year of study publication revealed a slight increase in the risk of HSIL in the 2001-2011 period and then a stabilization afterwards. This meta-analysis shows that the risk of HSIL is significantly increased in SLE patients, compared to healthy female controls. This suggests that women with SLE may benefit from HPV vaccines and specific cervical cancer screening. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Smoking and the risk of systemic lupus erythematosus: an updated systematic review and cumulative meta-analysis.

    Science.gov (United States)

    Jiang, Fan; Li, Suyun; Jia, Chongqi

    2015-11-01

    Published articles reported controversial results about the association of smoking with the risk of systemic lupus erythematosus (SLE). A meta-analysis was performed to assess the aforementioned association and arrive at a more precise estimate of effect. A comprehensive search was performed to identify case-control or cohort studies (from 1990 to 2015) of the aforementioned association. The I (2) statistic was used to examine between-study heterogeneity. Fixed or random effect model was selected based on heterogeneity test among studies. Publication bias was estimated using Egger's regression asymmetry test. A total of 12 published articles with 13 studies were finally included in our meta-analysis. Results showed that the pooled odds ratio (OR) for SLE risk was 1.56 (95% confidence interval (CI) = 1.26-1.95) among current smokers compared with nonsmokers. For ex-smokers versus nonsmokers, the pooled OR for SLE risk was 1.23 (95% CI = 0.93-1.63). Subgroup analysis by geographic location and cumulative meta-analysis were also analyzed. In conclusion, our meta-analysis suggested that smoking increased the risk of SLE. Further studies are needed to confirm this result.

  1. Association between interferon-γ +874 T/A polymorphism and susceptibility to autoimmune diseases: a meta-analysis.

    Science.gov (United States)

    Lee, Y H; Bae, S-C

    2016-06-01

    The aim of this study was to explore whether the interferon (IFN)-γ +874 T/A polymorphism plays a role in modifying the risk of autoimmune diseases. A meta-analysis was conducted on the association between the IFN-γ +874 T/A polymorphism and autoimmune diseases. Eighteen studies with a total of 2952 patients and 3832 controls were included in the meta-analysis. The meta-analysis revealed no association between autoimmune diseases and the IFN-γ +874 T allele in all study subjects (odds ratio (OR)=1.023, 95% confidence interval (CI) = 0.894-1.171, p = 0.738), but stratification by ethnicity indicated an association between the IFN-γ +874 T allele and autoimmune diseases in Latin American subjects (OR = 0.780, 95% CI = 0.629-0.953, p = 0.015). Meta-analysis also revealed an association between autoimmune diseases and the IFN-γ +874 T/A polymorphism in Caucasian and Middle Eastern subjects under a dominant inheritance model (OR = 0.686, 95% CI = 0.489-0.964, p = 0.003; OR = 1.414, 95% CI = 1.102-1.813, p = 0.006). Meta-analysis by autoimmune disease type indicated an association between ITP and the IFN-γ +874 T allele (OR = 1.753, 95% CI = 1.228-2.503, p = 0.002), but not for vasculitis, vitiligo, and auto-immune thyroid disease. Meta-analysis also showed a significant association between the IFN-γ +874 T/A polymorphism and systemic lupus erythematosus (SLE) under the dominant model (OR = 1.668, 95% CI = 1.114-2.497, p = 0.013). This meta-analysis indicates that the IFN-γ +874 T/A polymorphism may play a significant role in modifying the risk of autoimmune diseases in Caucasian, Latin American, and Middle Eastern subjects, and in particular shows that the IFN-γ +874 T/A polymorphism is associated with increased genetic susceptibility to idiopathic thrombocytopenic purpura and SLE. © The Author(s) 2015.

  2. Simulation of Blast Loading on an Ultrastructurally-based Computational Model of the Ocular Lens

    Science.gov (United States)

    2016-12-01

    work was started with the data available using Abaqus (simulia.com) and Tahoe (tahoe.sourceforge.net). Dedication First and foremost, this thesis is...42 3.45 Overlay of the Abaqus simulation with an image of the compressed lens. . . . . . . . 43 3.46 Graph of Data Produced From Tahoe Simulation and...using the fitted parameters and the theoretical data produced by the simulation within Abaqus . In order to get the 2 sets of data to match, the

  3. Methylenetetrahydrofolate reductase gene polymorphism and risk of chronic myelogenous leukemia: a meta-analysis.

    Science.gov (United States)

    Li, Chen; Yichao, Jin; Jiaxin, Lin; Yueting, Zhang; Qin, Lu; Tonghua, Yang

    2015-01-01

    Reported evidence supports a role for methylenetetrahydrofolate reductase (MTHFR) in the risk of chronic myelogenous leykemia (CML). However, these reports arrived at non-conclusive and even conflicting results regarding the association between two common MTHFR polymorphisms (C677T and A1298C) and CML risk. Thus, a meta-analysis was carried out to clarify a more precise association between these two polymorphisms and the CML risk by updating the available publications. Pooled odds ratios (OR) with corresponding 95% confidence interval (95% CI) and stratification analysis were performed to estimate the relationship between MTHFR polymorphisms and the risk of CML under different genetic comparison models. Data from the meta-analysis showed no significant association between MTHFR C677T polymorphism and CML risk. However, significant associations were found between MTHFR A1298C variants and CML risk under homozygous comparison model (CC vs AA, OR=1.62, 95% CI=1.11-2.36, p=0.01) and dominant comparison model (CC+AC vs AA, OR=1.68, 95% CI=1.17-2.43, p=0.005) in overall population; especially more obvious impacts were noticed for Asian populations in subgroup analysis for homozygous model (CC vs AA, OR=2.00, 95% CI=1.25-3.21, p=0.004) and dominant model (CC+AC vs AA, OR=2.49, 95% CI=1.42-4.36, p=0.001), but this did not apply in Caucasian populations. The results of this meta-analysis suggested no significant association between MTHFR C677T polymorphism and CML risk, while an increased CML risk was noticed for 1298C variant carriers, especially in Asian populations but not in Caucasian populations, which suggested ethnicity differences between MTHFR A1298C polymorphisms and risk of CML.

  4. Meditation for posttraumatic stress: Systematic review and meta-analysis.

    Science.gov (United States)

    Hilton, Lara; Maher, Alicia Ruelaz; Colaiaco, Benjamin; Apaydin, Eric; Sorbero, Melony E; Booth, Marika; Shanman, Roberta M; Hempel, Susanne

    2017-07-01

    We conducted a systematic review and meta-analysis that synthesized evidence from randomized controlled trials of meditation interventions to provide estimates of their efficacy and safety in treating adults diagnosed with posttraumatic stress disorder (PTSD). This review was based on an established protocol (PROSPERO: CRD42015025782) and is reported according to PRISMA guidelines. Outcomes of interest included PTSD symptoms, depression, anxiety, health-related quality of life, functional status, and adverse events. Meta-analyses were conducted using the Hartung-Knapp-Sidik-Jonkman method for random-effects models. Quality of evidence was assessed using the Grade of Recommendations Assessment, Development, and Evaluation (GRADE) approach. In total, 10 trials on meditation interventions for PTSD with 643 participants met inclusion criteria. Across interventions, adjunctive meditation interventions of mindfulness-based stress reduction, yoga, and the mantram repetition program improve PTSD and depression symptoms compared with control groups, but the findings are based on low and moderate quality of evidence. Effects were positive but not statistically significant for quality of life and anxiety, and no studies addressed functional status. The variety of meditation intervention types, the short follow-up times, and the quality of studies limited analyses. No adverse events were reported in the included studies; only half of the studies reported on safety. Meditation appears to be effective for PTSD and depression symptoms, but in order to increase confidence in findings, more high-quality studies are needed on meditation as adjunctive treatment with PTSD-diagnosed participant samples large enough to detect statistical differences in outcomes. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  5. Reliability of the Emergency Severity Index: Meta-analysis

    Directory of Open Access Journals (Sweden)

    Amir Mirhaghi

    2015-01-01

    Full Text Available Objectives: Although triage systems based on the Emergency Severity Index (ESI have many advantages in terms of simplicity and clarity, previous research has questioned their reliability in practice. Therefore, the aim of this meta-analysis was to determine the reliability of ESI triage scales. Methods: This metaanalysis was performed in March 2014. Electronic research databases were searched and articles conforming to the Guidelines for Reporting Reliability and Agreement Studies were selected. Two researchers independently examined selected abstracts. Data were extracted in the following categories: version of scale (latest/older, participants (adult/paediatric, raters (nurse, physician or expert, method of reliability (intra/inter-rater, reliability statistics (weighted/unweighted kappa and the origin and publication year of the study. The effect size was obtained by the Z-transformation of reliability coefficients. Data were pooled with random-effects models and a meta-regression was performed based on the method of moments estimator. Results: A total of 19 studies from six countries were included in the analysis. The pooled coefficient for the ESI triage scales was substantial at 0.791 (95% confidence interval: 0.787‒0.795. Agreement was higher with the latest and adult versions of the scale and among expert raters, compared to agreement with older and paediatric versions of the scales and with other groups of raters, respectively. Conclusion: ESI triage scales showed an acceptable level of overall reliability. However, ESI scales require more development in order to see full agreement from all rater groups. Further studies concentrating on other aspects of reliability assessment are needed.

  6. Meta-analysis on Macropore Flow Velocity in Soils

    Science.gov (United States)

    Liu, D.; Gao, M.; Li, H. Y.; Chen, X.; Leung, L. R.

    2017-12-01

    Macropore flow is ubiquitous in the soils and an important hydrologic process that is not well explained using traditional hydrologic theories. Macropore Flow Velocity (MFV) is an important parameter used to describe macropore flow and quantify its effects on runoff generation and solute transport. However, the dominant factors controlling MFV are still poorly understood and the typical ranges of MFV measured at the field are not defined clearly. To address these issues, we conducted a meta-analysis based on a database created from 246 experiments on MFV collected from 76 journal articles. For a fair comparison, a conceptually unified definition of MFV is introduced to convert the MFV measured with different approaches and at various scales including soil core, field, trench or hillslope scales. The potential controlling factors of MFV considered include scale, travel distance, hydrologic conditions, site factors, macropore morphologies, soil texture, and land use. The results show that MFV is about 2 3 orders of magnitude larger than the corresponding values of saturated hydraulic conductivity. MFV is much larger at the trench and hillslope scale than at the field profile and soil core scales and shows a significant positive correlation with the travel distance. Generally, higher irrigation intensity tends to trigger faster MFV, especially at field profile scale, where MFV and irrigation intensity have significant positive correlation. At the trench and hillslope scale, the presence of large macropores (diameter>10 mm) is a key factor determining MFV. The geometric mean of MFV for sites with large macropores was found to be about 8 times larger than those without large macropores. For sites with large macropores, MFV increases with the macropore diameter. However, no noticeable difference in MFV has been observed among different soil texture and land use. Comparing the existing equations to describe MFV, the Poiseuille equation significantly overestimated the

  7. Meta-analysis of prophylactic abdominal drainage in pancreatic surgery.

    Science.gov (United States)

    Hüttner, F J; Probst, P; Knebel, P; Strobel, O; Hackert, T; Ulrich, A; Büchler, M W; Diener, M K

    2017-05-01

    Intra-abdominal drains are frequently used after pancreatic surgery whereas their benefit in other gastrointestinal operations has been questioned. The objective of this meta-analysis was to compare abdominal drainage with no drainage after pancreatic surgery. PubMed, the Cochrane Library and Web of Science electronic databases were searched systematically to identify RCTs comparing abdominal drainage with no drainage after pancreatic surgery. Two independent reviewers critically appraised the studies and extracted data. Meta-analyses were performed using a random-effects model. Odds ratios (ORs) were calculated to aggregate dichotomous outcomes, and weighted mean differences for continuous outcomes. Summary effect measures were presented together with their 95 per cent confidence intervals. Some 711 patients from three RCTs were included. The 30-day mortality rate was 2·0 per cent in the drain group versus 3·4 per cent after no drainage (OR 0·68, 95 per cent c.i. 0·26 to 1·79; P = 0·43). The morbidity rate was 65·6 per cent in the drain group and 62·0 per cent in the no-drain group (OR 1·17, 0·86 to 1·60; P = 0·31). Clinically relevant pancreatic fistulas were seen in 11·5 per cent of patients in the drain group and 9·5 per cent in the no-drain group. Reinterventions, intra-abdominal abscesses and duration of hospital stay also showed no significant difference between the two groups. Pancreatic resection with, or without abdominal drainage results in similar rates of mortality, morbidity and reintervention. © 2017 BJS Society Ltd Published by John Wiley & Sons Ltd.

  8. Hepatitis E Seroprevalence in Europe: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Johannes Hartl

    2016-08-01

    Full Text Available There have been large numbers of studies on anti-HEV IgG seroprevalence in Europe, however, the results of these studies have produced high variability of seroprevalence rates, making interpretation increasingly problematic. Therefore, the aim of this study was to develop a clearer understanding of anti-HEV IgG seroprevalence in Europe and identify risk groups for HEV exposure by a meta-analysis of published studies. Methods: All European HEV-seroprevalence studies from 2003 to 2015 were reviewed. Data were stratified by assay, geographical location, and patient cohort (general population, patients with HIV, solid-organ transplant recipients, chronic liver disease patients, and individuals in contact with swine/wild animals. Data were pooled using a mixed-effects model. Results: Four hundred thirty-two studies were initially identified, of which 73 studies were included in the analysis. Seroprevalence estimates ranged from 0.6% to 52.5%, increased with age, but were unrelated to gender. General population seroprevalence varied depending on assays: Wantai (WT: 17%, Mikrogen (MG: 10%, MP-diagnostics (MP: 7%, DiaPro: 4%, Abbott 2%. The WT assay reported significantly higher seroprevalence rates across all cohorts (p < 0.001. Individuals in contact with swine/wild animals had significantly higher seroprevalence rates than the general population, irrespective of assay (p < 0.0001. There was no difference between any other cohorts. The highest seroprevalence was observed in France (WT: 32%, MP: 16% the lowest in Italy (WT: 7.5%, MP 0.9%. Seroprevalence varied between and within countries. The observed heterogeneity was attributed to geographical region (23%, assay employed (23% and study cohort (7%. Conclusion: Seroprevalcence rates primarily depend on the seroassy that is used, followed by the geographical region and study cohort. Seroprevalence is higher in individuals exposed to swine and/or wild animals, and increases with age.

  9. Hip geometry and femoral neck fractures: A meta-analysis.

    Science.gov (United States)

    Fajar, Jonny Karunia; Taufan, Taufan; Syarif, Muhammad; Azharuddin, Azharuddin

    2018-04-01

    Several studies have reported hip geometry to predict the femoral neck fractures. However, they showed inconsistency. To determine the association between hip geometry and femoral neck fractures. Published literature from PubMed and Embase databases (until May 25 th , 2017) was searched for eligible publications. The information related to (1) name of first author; (2) year of publication; (3) country of origin; (4) sample size of cases and controls and (5) mean and standard deviation of cases and controls were extracted. The pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association between hip geometry and femoral neck fractures were assessed using random or fixed effect model. A Comprehensive Meta-analysis software, version 2.0, was used to analyse the data. A total of 11 studies were included in this study. Our results showed that increase in hip axis length (OR 95% CI = 1.53 [1.06-2.21], p  = 0.025), femoral neck angle (OR 95% CI = 1.47 [1.01-2.15], p  = 0.044) and neck width (OR 95% CI = 2.68 [1.84-3.91], p  < 0.001) was associated with the risk of femoral neck fractures, whereas we could not find the correlation between femoral neck axis length and the risk of femoral neck fractures. There is strong evidence that elevated hip axis length, femoral neck angle and neck width are the risk factor for femoral neck fractures. The Translational Potential of this Article : Determining the hip axis length, femoral neck angle and neck width that are most highly associated with femoral neck fracture may allow clinicians to more accurately predict which individuals are likely to experience femoral neck fractures in the future.

  10. Gastrointestinal symptoms and obesity: a meta-analysis.

    Science.gov (United States)

    Eslick, G D

    2012-05-01

    Weight loss is a recognized alarm symptom for organic gastrointestinal (GI) disease, yet the association between obesity and specific GI symptoms remains poorly described. A meta-analysis was conducted to determine which GI symptoms predominate among obese individuals. A search of the literature using the databases MEDLINE, EMBASE PubMed and Current Contents (1950 - November 2011) was conducted. All studies assessing GI symptoms and increasing body mass index (BMI)/obesity were included. English and non-English articles were searched. A random effect model of the studies was undertaken. Overall, significant associations between GI symptoms and increasing BMI were found for upper abdominal pain (odds ratio [OR] = 2.65, 95% confidence interval [CI]: 1.23-5.72), gastroesophageal reflux (OR = 1.89, 95% CI: 1.70-2.09), diarrhoea (OR = 1.45, 95% CI: 1.26-1.64), chest pain/heartburn (OR = 1.74, 95% CI: 1.49-2.04), vomiting (OR = 1.76, 95% CI: 1.28-2.41), retching (OR = 1.33, 95% CI: 1.01-1.74) and incomplete evacuation (OR = 1.32, 95% CI: 1.03-1.71). However, no significant associations were found for all abdominal pain, lower abdominal pain, bloating, constipation/hard stools, fecal incontinence, nausea and anal blockage. Several key GI symptoms are associated with increasing BMI and obesity. In addition, there were a number of other GI symptoms that had no relationship with obesity. A greater knowledge of the GI symptoms associated with obesity along with the physiology will be important in the clinical management of these patients. © 2011 The Author. obesity reviews © 2011 International Association for the Study of Obesity.

  11. The prevalence of compulsive buying: a meta-analysis.

    Science.gov (United States)

    Maraz, Aniko; Griffiths, Mark D; Demetrovics, Zsolt

    2016-03-01

    To estimate the pooled prevalence of compulsive buying behaviour (CBB) in different populations and to determine the effect of age, gender, location and screening instrument on the reported heterogeneity in estimates of CBB and whether publication bias could be identified. Three databases were searched (Medline, PsychInfo, Web of Science) using the terms 'compulsive buying', 'pathological buying' and 'compulsive shopping' to estimate the pooled prevalence of CBB in different populations. Forty studies reporting 49 prevalence estimates from 16 countries were located (n = 32,000). To conduct the meta-analysis, data from non-clinical studies regarding mean age and gender proportion, geographical study location and screening instrument used to assess CBB were extracted by multiple independent observers and evaluated using a random-effects model. Four a priori subgroups were analysed using pooled estimation (Cohen's Q) and covariate testing (moderator and meta-regression analysis). The CBB pooled prevalence of adult representative studies was 4.9% (3.4-6.9%, eight estimates, 10,102 participants), although estimates were higher among university students: 8.3% (5.9-11.5%, 19 estimates, 14,947 participants) in adult non-representative samples: 12.3% (7.6-19.1%, 11 estimates, 3929 participants) and in shopping-specific samples: 16.2% (8.8-27.8%, 11 estimates, 4686 participants). Being young and female were associated with increased tendency, but not location (United States versus non-United States). Meta-regression revealed large heterogeneity within subgroups, due mainly to diverse measures and time-frames (current versus life-time) used to assess CBB. A pooled estimate of compulsive buying behaviour in the populations studied is approximately 5%, but there is large variation between samples accounted for largely by use of different time-frames and measures. © 2016 Society for the Study of Addiction.

  12. Induced Abortion: a Systematic Review and Meta-analysis.

    Science.gov (United States)

    Dastgiri, Saeed; Yoosefian, Maryam; Garjani, Mehraveh; Kalankesh, Leila R

    2017-03-01

    Induced abortion accounts for 1 in 8 of approximately 600000 maternal deaths that occur annually worldwide. Induced abortion rate can be considered as one of the indicators for assessing availability of the appropriate reproductive health plans for women and identifying needs for appropriate related health policies and programs. Researchers searched Pubmed, Google Scholar, CINAHL, Embase, PsycINFO, Cochrane, Iranian Scientific Information Database (SID), Iranian biomedical journals (Iranmedex), and Iranian Research Institute of Information and Documentation (Irandoc) between January 2000 and June 2013, which reported induced abortion. Search terms from two categories including abortion and termination of pregnancy were compiled. The search terms were "induced abortion", "illegal abortion", "illegal abortion", "unsafe abortion", and "criminal abortion". The search was also conducted with "induced termination of pregnancy", "illegal termination of pregnancy", "illegal termination of pregnancy", "unsafe termination of pregnancy" and "criminal termination of pregnancy". Meta-analysis was carried out by using OpenMeta software. Induced abortion rates were calculated based on the random effect model. Overall induced abortion rate was obtained 58.1 per 1000 women (95%CI: 55.16-61.04). In continental level, rate of induced abortion was 14 per 1000 women (95%CI: 11-16). Nation-wide and local rates were obtained 67.27 per 1000 women (95% CI: 60.02-74.23) and 148.92 (95% CI: 140.06-157.79) respectively. Induced abortion is a major public health problem that occurs worldwide whether under the legal restriction or freedom, and it remains as reproductive health concern globally. To eliminate the need for induced abortion is at the core of any effort for preventing this issue. Option with the highest priority is to prevent unwanted pregnancies through promoting reproductive health plans for women of reproductive age. In case the prevention strategies fail, universal provision of

  13. Psoriasis and suicidality: A systematic review and meta-analysis.

    Science.gov (United States)

    Singh, Sanminder; Taylor, Catherine; Kornmehl, Heather; Armstrong, April W

    2017-09-01

    Psoriasis is associated with psychiatric comorbidities; however, the relationship between psoriasis and suicidality is not well understood. To perform a systematic review and meta-analysis that elucidates the relationship between psoriasis and suicidality. Applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we systematically searched the PubMed, EMBASE, PsycINFO, and Cochrane databases. We searched literature published between 1946 and 2017. We identified 18 studies with a total of 1,767,583 participants, of whom 330,207 had psoriasis. On the basis of random effects modeling, the pooled odds ratio (OR) for suicidal ideation among patients with psoriasis was 2.05 (95% confidence interval [CI], 1.54-2.74). Patients with psoriasis were more likely to exhibit suicidal behaviors (combined attempted and completed suicides) with a pooled OR of 1.26 (95% CI, 1.13-1.40). Subgroup analysis showed that patients with psoriasis were more likely to attempt suicides (OR, 1.32; 95% CI, 1.14-1.54) and complete suicide (OR, 1.20; 95% CI, 1.04-1.39) than those without psoriasis. More severe psoriasis and younger age were associated with greater likelihood of suicidality. There are few studies examining suicidality in conjunction with psoriasis severity. Patients with psoriasis have a significantly higher likelihood of suicidal ideation, suicide attempts, and completed suicides. Among patients with psoriasis, those who are younger and whose psoriasis is more severe are at particular risk for suicidality. Copyright © 2017. Published by Elsevier Inc.

  14. dbMDEGA: a database for meta-analysis of differentially expressed genes in autism spectrum disorder.

    Science.gov (United States)

    Zhang, Shuyun; Deng, Libin; Jia, Qiyue; Huang, Shaoting; Gu, Junwang; Zhou, Fankun; Gao, Meng; Sun, Xinyi; Feng, Chang; Fan, Guangqin

    2017-11-16

    Autism spectrum disorders (ASD) are hereditary, heterogeneous and biologically complex neurodevelopmental disorders. Individual studies on gene expression in ASD cannot provide clear consensus conclusions. Therefore, a systematic review to synthesize the current findings from brain tissues and a search tool to share the meta-analysis results are urgently needed. Here, we conducted a meta-analysis of brain gene expression profiles in the current reported human ASD expression datasets (with 84 frozen male cortex samples, 17 female cortex samples, 32 cerebellum samples and 4 formalin fixed samples) and knock-out mouse ASD model expression datasets (with 80 collective brain samples). Then, we applied R language software and developed an interactive shared and updated database (dbMDEGA) displaying the results of meta-analysis of data from ASD studies regarding differentially expressed genes (DEGs) in the brain. This database, dbMDEGA ( https://dbmdega.shinyapps.io/dbMDEGA/ ), is a publicly available web-portal for manual annotation and visualization of DEGs in the brain from data from ASD studies. This database uniquely presents meta-analysis values and homologous forest plots of DEGs in brain tissues. Gene entries are annotated with meta-values, statistical values and forest plots of DEGs in brain samples. This database aims to provide searchable meta-analysis results based on the current reported brain gene expression datasets of ASD to help detect candidate genes underlying this disorder. This new analytical tool may provide valuable assistance in the discovery of DEGs and the elucidation of the molecular pathogenicity of ASD. This database model may be replicated to study other disorders.

  15. Living network meta-analysis compared with pairwise meta-analysis in comparative effectiveness research: empirical study

    Science.gov (United States)

    Nikolakopoulou, Adriani; Mavridis, Dimitris; Furukawa, Toshi A; Cipriani, Andrea; Tricco, Andrea C; Straus, Sharon E; Siontis, George C M; Egger, Matthias

    2018-01-01

    Abstract Objective To examine whether the continuous updating of networks of prospectively planned randomised controlled trials (RCTs) (“living” network meta-analysis) provides strong evidence against the null hypothesis in comparative effectiveness of medical interventions earlier than the updating of conventional, pairwise meta-analysis. Design Empirical study of the accumulating evidence about the comparative effectiveness of clinical interventions. Data sources Database of network meta-analyses of RCTs identified through searches of Medline, Embase, and the Cochrane Database of Systematic Reviews until 14 April 2015. Eligibility criteria for study selection Network meta-analyses published after January 2012 that compared at least five treatments and included at least 20 RCTs. Clinical experts were asked to identify in each network the treatment comparison of greatest clinical interest. Comparisons were excluded for which direct and indirect evidence disagreed, based on side, or node, splitting test (Pmeta-analysis. The frequency and time to strong evidence was compared against the null hypothesis between pairwise and network meta-analyses. Results 49 comparisons of interest from 44 networks were included; most (n=39, 80%) were between active drugs, mainly from the specialties of cardiology, endocrinology, psychiatry, and rheumatology. 29 comparisons were informed by both direct and indirect evidence (59%), 13 by indirect evidence (27%), and 7 by direct evidence (14%). Both network and pairwise meta-analysis provided strong evidence against the null hypothesis for seven comparisons, but for an additional 10 comparisons only network meta-analysis provided strong evidence against the null hypothesis (P=0.002). The median time to strong evidence against the null hypothesis was 19 years with living network meta-analysis and 23 years with living pairwise meta-analysis (hazard ratio 2.78, 95% confidence interval 1.00 to 7.72, P=0.05). Studies directly comparing

  16. Ethnic Differences in Genetic Ion Channelopathies Associated with Sudden Cardiac Death: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Kong, Tim; Feulefack, Joseph; Ruether, Kim; Shen, Fan; Zheng, Wang; Chen, Xing-Zhen; Sergi, Consolato

    2017-08-01

    Reports of allele frequencies encoding ion channel, or their interacting proteins associated with sudden cardiac death among different ethnic groups have been inconsistent. Here, we aimed to characterize the distribution of these genes and their alleles among various ethnicities through meta-analysis. We conducted a systematic review and meta-analysis to assess the mean allele frequencies of channelopathy genes SCN5A, NOS1AP, KCNH2, KCNE1 , and KCNQ1 among the Black, Caucasian, Asian, and Hispanic ethnicities. Searches in PubMed, Google Scholar, and Web of Science resulted in 18 reports published before July 2015 that met the eligible criteria. Allele frequencies were averaged by weight, and pooled values were calculated by inverse variance. Fixed-effects and random-effects models were used to pool effect sizes within each study and across different studies, respectively. Moreover, to extend our findings, we used sequenced genomic data from the Exome Aggregation Consortium to compare allele frequencies between different ethnicities. Meta-analysis of published studies supports that Asians had the highest overall mean allele frequencies of NOS1AP (0.36%, 95% CI: 0.30, 0.43; P <0.001), and SCN5A frequencies (0.17%, 95% CI: 0.07, 0.27, P =0.001), and whereas Caucasians had the highest KCNH2 frequency (0.21%, 95% CI: 0.16, 0.25; P <0.001), and Hispanics the highest KCNQ1 frequency (0.16%). Analysis of the Exome Aggregation Consortium also provided consistent data in agreement the meta-analysis. Overall, Asians carried the most alleles of genes associated with sudden cardiac death. The meta-analysis reveals significant differences in allele distribution of channelopathy-associated genes among different ethnic groups. © 2017 by the Association of Clinical Scientists, Inc.

  17. Complications and Carcinogenic Effects of Mustard Gas--a Systematic Review and Meta-Analysis in Iran.

    Science.gov (United States)

    Panahi, Yunes; Gholami, Nasrin; Ghojazadeh, Morteza; Moslemi, Farnaz; Naghavi-Behzad, Mohammad; Azami-Aghdash, Saber; Ghaffari, Alireza; Piri, Reza

    2015-01-01

    Catastrophic effects of mustard gas as a chemical warfare agent have always been a major problem for those exposed to this agent. In this meta-analysis it was tried to evaluate carcinogenesis, ocular, cutaneous and respiratory complications of mustard gas exposure among Iranians who had been exposed to this agent during the Iran-Iraq war. In this meta-analysis, the required data were collected using keywords "mustard gas", "sulfur mustard", "cancer", "neoplasm", "respiratory complications", "ocular complications" , "lung disease", "chronic complication", "eye", "skin", "cutaneous complication", "carcinogenesis" and their combination with keywords "Iran", "Iranian", "prevalence", "mortality" and their Farsi equivalent terms from the databases of SID, Iranmedex, Magiran, Pubmed, Science Direct, Google Search engine, Gray Literature and Reference of References. To determine the prevalence of each complication and perform meta-analysis, CMA: 2 (Comprehensive Meta-Analysis) software with a randomized model was used. Of the 542 articles found, 7 national articles, consistent with the aims of this study were selected. Meta- analysis of seven papers revealed that cancer risk, especially cancer of the respiratory system was elevated, so that the relative risk (RR) of cancer role of mustard gas was inconsistent from 2/1 to 4 in this survey. Also prevalence of delayed skin disorders due to sulfur mustard was 94.6%, pulmonary complications 94.5% and ocular complications 89.9%. The incidence of various cancers in victims exposed to mustard gas was 1.7% worldwide where the rate was 2.2% in Iranian victims of the Iraq-Iran war. Based on present study the prevalence of delayed mustard gas related cutaneous, pulmonary and ocular complications is above 90% and risk of carcinogenesis is higher in comparison to worldwide statistics. This may suggest need for long-term and persistent follow-up and rehabilitation procedures for populations exposed to this agent.

  18. Surgical Treatment and Survival in Patients with Liver Metastases from Neuroendocrine Tumors: A Meta-Analysis of Observational Studies

    Directory of Open Access Journals (Sweden)

    Stefano Bacchetti

    2013-01-01

    Full Text Available Introduction. The role of hepatic resection in patients with liver metastases from gastroenteropancreatic neuroendocrine tumors (GEP-NETs is still poorly defined. Therefore, we examined the results obtained with surgical resection and other locoregional or systemic therapies by reviewing the recent literature on this topic. We performed the meta-analysis for comparing surgical resection of hepatic metastases with other treatments. Materials and Methods. In this systematic review and meta-analysis of observational studies, the literature search was undertaken between 1990 and 2012 looking for studies evaluating the different survivals between patients treated with surgical resection of hepatic metastases and with other surgical or nonsurgical therapies. The studies were evaluated for quality, publication bias, and heterogeneity. Pooled hazard ratio (HR estimates and 95% confidence intervals (CI.95 were calculated using fixed-effects model. Results. We selected six studies in the review, five of which were suitable for meta-analysis. We found a significant longer survival in patients treated with hepatic resection than embolisation HR 0.34 (CI.95 0.21–0.55 or all other nonsurgical treatments HR 0.45 (CI.95 0.34–0.60. Only one study compared surgical resection with liver transplantation and meta-analysis was not feasible. Conclusions. Our meta-analysis provides evidence supporting the hypothesis that hepatic resection increases overall survival in patients with liver metastases from GEP-NETs. Further randomized clinical trials are needed to confirm these findings and it would be desirable to identify new markers to properly select patients for surgical treatment.

  19. Association between MTHFR A1298C polymorphism and male infertility: A meta-analysis.

    Science.gov (United States)

    Zhang, Qiang; Yin, Guo-Ying; Liu, Juan; Liang, Yue; Li, Yao-Yan; Zhao, Jing-Yu; Zhang, Li-Wen; Wang, Bai-Qi; Tang, Nai-Jun

    2017-04-01

    There have been several epidemiological studies evaluating the potential association between the methylenetetrahydrofolate reductase (MTHFR) A1298C polymorphism and the risk of male infertility. However, the results obtained were inconsistent. Therefore, we performed a meta-analysis to further examine the association between the MTHFR A1298C polymorphism and male infertility. A comprehensive search was conducted to identify all eligible studies from the online literature databases published prior to January 15th, 2016. A total of 20 studies with 4293 cases and 4507 controls were included. An odds ratio (OR) and a 95% confidence interval (95% CI) were calculated to assess the strength of the association. A cumulative meta-analysis, sensitivity analysis and assessment of the publication bias were also performed in this study. The results showed that in the overall analysis, the association between the MTHFR A1298C polymorphism and male infertility was not significant. A stratified analysis by ethnicity revealed a significant increase in the risk of male infertility in the Asian population with the MTHFR A1298C polymorphism (especially in the heterozygote model: OR=1.20, 95% CI=1.01-1.44, P=0.994; the dominant model: OR=1.23, 95% CI=1.04-1.45, P=0.996; and the allele model: OR=1.20, 95% CI=1.04-1.39, P=0.985) but not in the Caucasian population. In the stratified analyses, no significant association was observed between the different types of male infertility. This meta-analysis suggests the MTHFR A1298C polymorphism may be a potential risk factor for male infertility, especially in the Asian population.

  20. Network meta-analysis of multiple outcome measures accounting for borrowing of information across outcomes.

    Science.gov (United States)

    Achana, Felix A; Cooper, Nicola J; Bujkiewicz, Sylwia; Hubbard, Stephanie J; Kendrick, Denise; Jones, David R; Sutton, Alex J

    2014-07-21

    Network meta-analysis (NMA) enables simultaneous comparison of multiple treatments while preserving randomisation. When summarising evidence to inform an economic evaluation, it is important that the analysis accurately reflects the dependency structure within the data, as correlations between outcomes may have implication for estimating the net benefit associated with treatment. A multivariate NMA offers a framework for evaluating multiple treatments across multiple outcome measures while accounting for the correlation structure between outcomes. The standard NMA model is extended to multiple outcome settings in two stages. In the first stage, information is borrowed across outcomes as well across studies through modelling the within-study and between-study correlation structure. In the second stage, we make use of the additional assumption that intervention effects are exchangeable between outcomes to predict effect estimates for all outcomes, including effect estimates on outcomes where evidence is either sparse or the treatment had not been considered by any one of the studies included in the analysis. We apply the methods to binary outcome data from a systematic review evaluating the effectiveness of nine home safety interventions on uptake of three poisoning prevention practices (safe storage of medicines, safe storage of other household products, and possession of poison centre control telephone number) in households with children. Analyses are conducted in WinBUGS using Markov Chain Monte Carlo (MCMC) simulations. Univariate and the first stage multivariate models produced broadly similar point estimates of intervention effects but the uncertainty around the multivariate estimates varied depending on the prior distribution specified for the between-study covariance structure. The second stage multivariate analyses produced more precise effect estimates while enabling intervention effects to be predicted for all outcomes, including intervention effects on

  1. TLR9 polymorphisms and systemic lupus erythematosus risk: an update meta-analysis study.

    Science.gov (United States)

    Wang, Duan; Zhang, Chao; Zhou, Zongke; Pei, Fuxing

    2016-04-01

    It has been reported that the Toll-like receptor 9 (TLR9) gene polymorphisms may be associated with systemic lupus erythematosus (SLE) risk. However, some studies yielded conflicting results. Therefore, a comprehensive meta-analysis was performed to assess the precise association between TLR9 polymorphisms and SLE susceptibility. We performed a systematic search in PubMed, Embase (Ovid), China National Knowledge Internet, and Wanfang databases up to July 15, 2015. Odds ratio (OR) and 95 % confidence interval (CI) were used to pool the effect size. Statistical analyses were performed with STATA 11.0 software. In total, 21 studies from nineteen articles with 10,273 subjects were included in this meta-analysis. The overall results suggested that there was a statistically significant association between TLR9 rs187084 polymorphism and SLE risk observed in recessive model (TT vs. TC + CC: OR 1.17, 95 % CI 1.05-1.30, P = 0.005), codominant model (TT vs. CC: OR 1.22, 95 % CI 1.03-1.43, P = 0.019), and allele model (T vs. C: OR 1.15, 95 % CI 1.02-1.30, P = 0.020) in Asians. However, we found that there may be no significant association between the other three TLR9 polymorphisms and SLE risk in either Asians or non-Asians. In conclusion, the meta-analysis results suggested that TLR9 rs187084 polymorphism may increase the risk of SLE in Asians. However, no significant association between TLR9 SNPs (rs352139, rs352140, and rs5743836) and SLE risk was identified.

  2. The HLA-G 14-bp polymorphism and recurrent implantation failure: a meta-analysis.

    Science.gov (United States)

    Fan, Wei; Huang, Zhongying; Li, Shangwei; Xiao, Zhun

    2017-11-01

    The human leucocyte antigen-G (HLA-G) 14-bp insertion/deletion polymorphism was implicated in recurrent implantation failure (RIF), but individual published studies showed inconclusive results. Thus, a meta-analysis was performed to clarify the effect of HLA-G 14-bp polymorphism on RIF risk. A comprehensive search for relevant articles was conducted. The odds ratios (ORs) and 95% confidence intervals (CIs) for HLA-G 14-bp polymorphism and RIF were calculated. A total of five studies were included. In studies conducted in RIF patients and controls who had at least one spontaneous pregnancy, meta-analysis revealed no statistically significant association between the HLA-G 14-bp polymorphism and RIF in allele contrast and all genetic models in the overall population, but significant association was found in the population of Caucasian origin under allele contrast (OR = 1.73, 95% CI, 1.20, 2.50) and genetic models of +14 bp/+14 bp vs. -14 bp/-14 bp (OR = 3.09, 95% CI, 1.43, 6.65). In studies conducted in RIF patients and controls who had successful pregnancy following IVF-ET, the meta-analysis showed that there was statistically significant association between the HLA-G 14 bp polymorphism and RIF in allele contrast (OR = 1.74, 95% CI, 1.13, 2.67) and genetic models of +14 bp/+14 bp vs. -14 bp/-14 bp (OR = 10.20, 95% CI, 2.47, 42.14) and dominant model (OR = 4.34, 95% CI, 1.72, 10.92). No publication bias was found in the present studies. This meta-analysis suggested that the HLA-G 14-bp insertion allele may increase the risk of RIF in Caucasians. Further studies with large sample size of different ethnic populations are necessary.

  3. Meta-analysis of the research impact of Baddeley’s multicomponent working memory model and Cowan’s embedded-processes model of working memory: A bibliometric mapping approach

    Directory of Open Access Journals (Sweden)

    Gruszka Aleksandra

    2016-04-01

    Full Text Available In this study bibliometric mapping method was employed to visualise the current research trends and the impact of the two most influential models of working memory, namely: A. D. Baddeley and G. J. Hitch’s (1974 multicomponent working memory model and N. Cowan’s (1988 embedded-processes model of working memory. Using VOSviewer software two maps were generated based on the index-term words extracted from the research papers citing Baddeley (2000 and Cowan (2001, respectively. The maps represent networks of co-occurrences of index terms and can be interpreted as an indication of the main research fields related to the examined models of WM. The results of the analysis revealed that the spheres of influence of the two main conceptualisations of WM are rather different than similar. Although the first two clusters, i.e. “brain mapping” and “higher-level cognition and development” are present in both maps, their relative importance varies. The remaining clusters are unique to each map. Baddeley’s theory seems to have a greater influence on “neuropsychology”, while Cowan’s theory - on basic research on “biological systems”, including the nervous system in humans and animals. The second difference between these theories concerns their relations to functions and dysfunctions associated with particular sensory modalities: in Baddelay’s theory with the “auditory modality” cluster, and in Cowan’s - with the “visual modality” one.

  4. An Experimental Model to Study the Impact of Lipid Oxidation on Contact Lens Deposition In Vitro.

    Science.gov (United States)

    Schuett, Burkhardt S; Millar, Thomas J

    2017-09-01

    This study was to establish a controlled in vitro test system to study the effect of lipid oxidation on lipid deposition on contact lenses. Fatty acids with varying degree of unsaturation were oxidized using the Fenton reaction. The degree of lipid oxidation and the lipid moieties formed during the oxidation were identified and estimated by various lipid staining techniques following separation with thin-layer chromatography, and by measuring thiobarbituric acid reactive substances or peroxides in solution. Two different silicone hydrogel-based contact lenses (Balafilcon A and Senofilcon A) were incubated with fatty acids laced with radioactive tracer oxidized to varying degrees, and the amount of lipid deposition was measured using unoxidized lipid samples as controls. The Fenton reaction together with the analytical methods to analyze the lipid oxidation can be used to control oxidation of lipids to a desired amount. In general, saturated fatty acids are not oxidized, the monounsaturated oleic acid produced peroxides while poly-unsaturated lipids initially produced peroxides and then fragmented into reactive aldehydes. Incubation with mildly oxidized lipids (most likely lipid peroxides) resulted in increased lipid deposition on Balafilcon A lenses compared to unoxidized lipids, but this was not observed for Senofilcon A lenses. Further oxidation of the lipids (carbon chain breakup) on the other hand resulted in diminished lipid deposition for both contact lens types. This study provides a method for inducing and controlling lipid oxidation so that the effect of lipid oxidation on contact lens binding can be compared. It could be shown that the degree of lipid oxidation has different effects on the lipid deposition on different contact lens types.

  5. A Healthy Dietary Pattern Reduces Lung Cancer Risk: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Sun, Yanlai; Li, Zhenxiang; Li, Jianning; Li, Zengjun; Han, Jianjun

    2016-03-04

    Diet and nutrients play an important role in cancer development and progress; a healthy dietary pattern has been found to be associated with several types of cancer. However, the association between a healthy eating pattern and lung cancer risk is still unclear. Therefore, we conducted a systematic review with meta-analysis to evaluate whether a healthy eating pattern might reduce lung cancer risk. We identified relevant studies from the PubMed and Embase databases up to October 2015, and the relative risks were extracted and combined by the fixed-effects model when no substantial heterogeneity was observed; otherwise, the random-effects model was employed. Subgroup and publication bias analyses were also performed. Finally, eight observational studies were included in the meta-analysis. The pooled relative risk of lung cancer for the highest vs. lowest category of healthy dietary pattern was 0.81 (95% confidence interval, CI: 0.75-0.86), and no significant heterogeneity was detected. The relative risks (RRs) for non-smokers, former smokers and current smokers were 0.89 (95% CI: 0.63-1.27), 0.74 (95% CI: 0.62-0.89) and 0.86 (95% CI: 0.79-0.93), respectively. The results remained stable in subgroup analyses by other confounders and sensitivity analysis. The results of our meta-analysis suggest that a healthy dietary pattern is associated with a lower lung cancer risk, and they provide more beneficial evidence for changing the diet pattern in the general population.

  6. Bleeding risk under selective serotonin reuptake inhibitor (SSRI) antidepressants: A meta-analysis of observational studies.

    Science.gov (United States)

    Laporte, Silvy; Chapelle, Céline; Caillet, Pascal; Beyens, Marie-Noëlle; Bellet, Florelle; Delavenne, Xavier; Mismetti, Patrick; Bertoletti, Laurent

    2017-04-01

    Selective serotonin reuptake inhibitors (SSRIs) have been reported to be potentially associated with an increased risk of bleeding. A meta-analysis of observational studies was conducted to quantify this risk. Case-control and cohort studies investigating bleeding risk under SSRI therapy were retrieved by searching the Medline, Pascal, Google Scholar and Scopus databases. Case-control studies were included if they reported bleeding incidents with and without the use of SSRIs and cohort studies were included if they reported the rate of bleeds among SSRI users and non-users. The main outcome was severe bleeding, whatever the site. Only data concerning SSRI belonging to the ATC class N06AB were used. For both case-control and cohort studies, we recorded the adjusted effect estimates and their 95% confidence intervals (CI). Pooled adjusted odds ratio (OR) estimates were computed for case-control and cohort studies using an inverse-variance model. Meta-analysis of the adjusted ORs of 42 observational studies showed a significant association between SSRI use and the risk of bleeding [OR 1.41 (95% CI 1.27-1.57), random effect model, prisk of 41% of bleeding [OR 1.41 (95% CI 1.25-1.60)], as well as for the 11 cohort studies including 187,956 patients [OR 1.36 (95% CI 1.12-1.64)]. Subgroup analyses showed that the association remained constant whatever the characteristics of studies. This meta-analysis shows an increased risk of bleeding of at least 36% (from 12% to 64%) based on the high-level of observational studies with SSRIs use. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Circulating folate levels and colorectal adenoma: a case-control study and a meta-analysis.

    Science.gov (United States)

    Park, Yeong Mi; Youn, Jiyoung; Cho, Chang Ho; Kim, Sung Hi; Lee, Jung Eun

    2017-10-01

    The relationship between folate and colorectal neoplasia remains controversial. We examined the association between serum folate concentrations and colorectal adenomas in a case-control study of Korean adults and conducted a meta-analysis. Our case-control study included 113 pairs of case and control who underwent colonoscopy and provided blood samples. We used multivariable conditional logistic regression models to obtain the odds ratios and 95% confidence interval (CIs). For meta-analysis, we identified the relevant studies by searching the PubMed database up to February 2017, included our case-control study and combined the study-specific relative risks (RRs) using a random-effects model. In this case-control study, we included 58 men and 55 women with colorectal adenomas and sex and fasting status matched the controls. We did not find any significant association between the serum folate levels and colorectal adenomas in either men or women. For meta-analysis, a total of eleven studies were included in our analysis and classified into two groups; polyp clearance group (PC) for the studies that included participants who underwent endoscopies and had their polyps removed at baseline; and no polyp clearance group (NPC) for the studies that included participants whose histories of endoscopies were unknown or who underwent their first endoscopies. Four PC (1,311 cases and 1,672 non-cases) and eight NPC studies (3,501 cases and 11,347 non-cases) were included. The combined RRs (95% CIs) comparing the bottom with the top categories of circulating folate levels were 1.07 (0.97-1.18) for the NPC group but 1.45 (1.16-1.74) for the PC group. Low circulating folate levels were associated with new adenoma formation.

  8. A Healthy Dietary Pattern Reduces Lung Cancer Risk: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yanlai Sun

    2016-03-01

    Full Text Available Background: Diet and nutrients play an important role in cancer development and progress; a healthy dietary pattern has been found to be associated with several types of cancer. However, the association between a healthy eating pattern and lung cancer risk is still unclear. Objective: Therefore, we conducted a systematic review with meta-analysis to evaluate whether a healthy eating pattern might reduce lung cancer risk. Methods: We identified relevant studies from the PubMed and Embase databases up to October 2015, and the relative risks were extracted and combined by the fixed-effects model when no substantial heterogeneity was observed; otherwise, the random-effects model was employed. Subgroup and publication bias analyses were also performed. Results: Finally, eight observational studies were included in the meta-analysis. The pooled relative risk of lung cancer for the highest vs. lowest category of healthy dietary pattern was 0.81 (95% confidence interval, CI: 0.75–0.86, and no significant heterogeneity was detected. The relative risks (RRs for non-smokers, former smokers and current smokers were 0.89 (95% CI: 0.63–1.27, 0.74 (95% CI: 0.62–0.89 and 0.86 (95% CI: 0.79–0.93, respectively. The results remained stable in subgroup analyses by other confounders and sensitivity analysis. Conclusions: The results of our meta-analysis suggest that a healthy dietary pattern is associated with a lower lung cancer risk, and they provide more beneficial evidence for changing the diet pattern in the general population.

  9. The correlation of social support with mental health: A meta-analysis.

    Science.gov (United States)

    Harandi, Tayebeh Fasihi; Taghinasab, Maryam Mohammad; Nayeri, Tayebeh Dehghan

    2017-09-01

    Social support is an important factor that can affect mental health. In recent decades, many studies have been done on the impact of social support on mental health. The purpose of the present study is to investigate the effect size of the relationship between social support and mental health in studies in Iran. This meta-analysis was carried out in studies that were performed from 1996 through 2015. Databases included SID and Magiran, the comprehensive portal of human sciences, Noor specialized magazine databases, IRANDOC, Proquest, PubMed, Scopus, ERIC, Iranmedex and Google Scholar. The keywords used to search these websites included "mental health or general health," and "Iran" and "social support." In total, 64 studies had inclusion criteria meta-analysis. In order to collect data used from a meta-analysis worksheet that was made by the researcher and for data analysis software, CMA-2 was used. The mean of effect size of the 64 studies in the fixed-effect model and random-effect model was obtained respectively as 0.356 and 0.330, which indicated the moderate effect size of social support on mental health. The studies did not have publication bias, and enjoyed a heterogeneous effect size. The target population and social support questionnaire were moderator variables, but sex, sampling method, and mental health questionnaire were not moderator variables. Regarding relatively high effect size of the correlation between social support and mental health, it is necessary to predispose higher social support, especially for women, the elderly, patients, workers, and students.

  10. Fasting insulin, insulin resistance and risk of hypertension in the general population: A meta-analysis.

    Science.gov (United States)

    Wang, Feng; Han, Lili; Hu, Dayi

    2017-01-01

    Studies on the association of fasting insulin concentrations or insulin resistance with subsequent risk of hypertension have yielded conflicting results. To quantitatively assess the association of fasting insulin concentrations or homeostasis model assessment insulin resistance (HOMA-IR) with incident hypertension in a general population by performing a meta-analysis. We searched the PubMed and Embase databases until August 31, 2016 for prospective observational studies investigating the elevated fasting insulin concentrations or HOMA-IR with subsequent risk of hypertension in the general population. Pooled risk ratio (RR) and 95% confidence interval (CI) of hypertension was calculated for the highest versus the lowest category of fasting insulin or HOMA-IR. Eleven studies involving 10,230 hypertension cases were identified from 55,059 participants. Meta-analysis showed that the pooled adjusted RR of hypertension was 1.54 (95% CI 1.34-1.76) for fasting insulin concentrations and 1.43 (95% CI 1.27-1.62) for HOMA-IR comparing the highest to the lowest category. Subgroup analysis results showed that the association of fasting insulin concentrations with subsequent risk of hypertension seemed more pronounced in women (RR 2.07; 95% CI 1.19-3.60) than in men (RR 1.48; 95% CI 1.17-1.88). This meta-analysis suggests that elevated fasting insulin concentrations or insulin resistance as estimated by homeostasis model assessment is independently associated with an exacerbated risk of hypertension in the general population. Early intervention of hyperinsulinemia or insulin resistance may help clinicians to identify the high risk of hypertensive population. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Performance of selected imputation techniques for missing variances in meta-analysis

    Science.gov (United States)

    Idris, N. R. N.; Abdullah, M. H.; Tolos, S. M.

    2013-04-01

    A common method of handling the problem of missing variances in meta-analysis of continuous response is through imputation. However, the performance of imputation techniques may be influenced by the type of model utilised. In this article, we examine through a simulation study the effects of the techniques of imputation of the missing SDs and type of models used on the overall meta-analysis estimates. The results suggest that imputation should be adopted to estimate the overall effect size, irrespective of the model used. However, the accuracy of the estimates of the corresponding standard error (SE) is influenced by the imputation techniques. For estimates based on the fixed effects model, mean imputation provides better estimates than multiple imputations, while those based on the random effects model responds more robustly to the type of imputation techniques. The results showed that although imputation is good in reducing the bias in point estimates, it is more likely to produce coverage probability which is higher than the nominal value.

  12. Efficacy of escitalopram compared to citalopram: a meta-analysis.

    Science.gov (United States)

    Montgomery, Stuart; Hansen, Thomas; Kasper, Siegfried

    2011-03-01

    The aim of this review was to assess the clinical relevance of the relative antidepressant efficacy of escitalopram and citalopram by meta-analysis. Studies in major depressive disorder (MDD) with both escitalopram and citalopram treatment arms were identified. Adult patients had to meet DSM-IV criteria for MDD. The primary outcome measure was the treatment difference in Montgomery-Asberg Depression Rating Scale (MADRS) total score at week 8 (or last assessment if escitalopram, n=995; citalopram, n=1014). Escitalopram was significantly more effective than citalopram in overall treatment effect, with an estimated mean treatment difference of 1.7 points at week 8 (or last assessment if escitalopram. In this meta-analysis, the statistically significant superior efficacy of escitalopram compared to citalopram was shown to be clinically relevant.

  13. Meta-Analysis of Correlations Among Usability Measures

    DEFF Research Database (Denmark)

    Hornbæk, Kasper Anders Søren; Effie Lai Chong, Law

    2007-01-01

    Understanding the relation between usability measures seems crucial to deepen our conception of usability and to select the right measures for usability studies. We present a meta-analysis of correlations among usability measures calculated from the raw data of 73 studies. Correlations are genera......Understanding the relation between usability measures seems crucial to deepen our conception of usability and to select the right measures for usability studies. We present a meta-analysis of correlations among usability measures calculated from the raw data of 73 studies. Correlations...... ± .062. Changes in task complexity do not influence these correlations, but use of more complex measures attenuates them. Standard questionnaires for measuring satisfaction appear more reliable than homegrown ones. Measures of users' perceptions of phenomena are generally not correlated with objective...

  14. Meta-Analysis of Social Cognition in Mild Cognitive Impairment.

    Science.gov (United States)

    Bora, Emre; Yener, Görsev G

    2017-07-01

    Social cognitive abilities are impaired in Alzheimer disease and other dementias. Recent studies suggested that social cognitive abilities might be also impaired in mild cognitive impairment (MCI). Current meta-analysis aimed to summarize available evidence for deficits in theory of mind (ToM) and emotion recognition in MCI. In this meta-analysis of 17 studies, facial emotion recognition and ToM performances of 513 individuals with MCI and 693 healthy controls were compared. Mild cognitive impairment was associated with significant impairments falling in the medium effect sizes range in ToM ( d = 0.63) and facial emotion recognition ( d = 0.58). Among individual emotions, recognition of fear and sadness were particularly impaired. There were no significant between-group differences in recognition of disgust, happiness, and surprise. Social cognitive deficits were more severe in multidomain MCI. There is a need for longitudinal studies investigating the potential role of social cognitive impairment in predicting conversion to dementia.

  15. The prevalence of food allergy: A meta-analysis

    DEFF Research Database (Denmark)

    Rona, Roberto J.; Keil, Thomas; Summers, Colin

    2007-01-01

    Background: There is uncertainty about the prevalence of food allergy in communities. Objective: To assess the prevalence of food allergy by performing a meta-analysis according to the method of assessment used. Methods: The foods assessed were cow's milk, hen's egg, peanut, fish, shellfish......, and an overall estimate of food allergy. We summarized the information in 5 categories: self-reported symptoms, specific IgE positive, specific skin prick test positive, symptoms combined with sensitization, and food challenge studies. We systematically searched MEDLINE and EMBASE for publications since 1990....... The meta-analysis included only original studies. They were stratified by age groups: infant/preschool, school children, and adults. Results: A total of 934 articles were identified, but only 51 were considered appropriate for inclusion. The prevalence of self-reported food allergy was very high compared...

  16. Computer use and carpal tunnel syndrome: A meta-analysis.

    Science.gov (United States)

    Shiri, Rahman; Falah-Hassani, Kobra

    2015-02-15

    Studies have reported contradictory results on the role of keyboard or mouse use in carpal tunnel syndrome (CTS). This meta-analysis aimed to assess whether computer use causes CTS. Literature searches were conducted in several databases until May 2014. Twelve studies qualified for a random-effects meta-analysis. Heterogeneity and publication bias were assessed. In a meta-analysis of six studies (N=4964) that compared computer workers with the general population or other occupational populations, computer/typewriter use (pooled odds ratio (OR)=0.72, 95% confidence interval (CI) 0.58-0.90), computer/typewriter use ≥1 vs. computer/typewriter use ≥4 vs. computer/typewriter use (pooled OR=1.34, 95% CI 1.08-1.65), mouse use (OR=1.93, 95% CI 1.43-2.61), frequent computer use (OR=1.89, 95% CI 1.15-3.09), frequent mouse use (OR=1.84, 95% CI 1.18-2.87) and with years of computer work (OR=1.92, 95% CI 1.17-3.17 for long vs. short). There was no evidence of publication bias for both types of studies. Studies that compared computer workers with the general population or several occupational groups did not control their estimates for occupational risk factors. Thus, office workers with no or little computer use are a more appropriate comparison group than the general population or several occupational groups. This meta-analysis suggests that excessive computer use, particularly mouse usage might be a minor occupational risk factor for CTS. Further prospective studies among office workers with objectively assessed keyboard and mouse use, and CTS symptoms or signs confirmed by a nerve conduction study are needed. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Air pollution and quality of sperm: a meta-analysis.

    Science.gov (United States)

    Fathi Najafi, Tahereh; Latifnejad Roudsari, Robab; Namvar, Farideh; Ghavami Ghanbarabadi, Vahid; Hadizadeh Talasaz, Zahra; Esmaeli, Mahin

    2015-04-01

    Air pollution is common in all countries and affects reproductive functions in men and women. It particularly impacts sperm parameters in men. This meta-analysis aimed to examine the impact of air pollution on the quality of sperm. The scientific databases of Medline, PubMed, Scopus, Google scholar, Cochrane Library, and Elsevier were searched to identify relevant articles published between 1978 to 2013. In the first step, 76 articles were selected. These studies were ecological correlation, cohort, retrospective, cross-sectional, and case control ones that were found through electronic and hand search of references about air pollution and male infertility. The outcome measurement was the change in sperm parameters. A total of 11 articles were ultimately included in a meta-analysis to examine the impact of air pollution on sperm parameters. The authors applied meta-analysis sheets from Cochrane library, then data extraction, including mean and standard deviation of sperm parameters were calculated and finally their confidence interval (CI) were compared to CI of standard parameters. The CI for pooled means were as follows: 2.68 ± 0.32 for ejaculation volume (mL), 62.1 ± 15.88 for sperm concentration (million per milliliter), 39.4 ± 5.52 for sperm motility (%), 23.91 ± 13.43 for sperm morphology (%) and 49.53 ± 11.08 for sperm count. The results of this meta-analysis showed that air pollution reduces sperm motility, but has no impact on the other sperm parameters of spermogram.

  18. Drivers of wetland conversion: a global meta-analysis.

    Directory of Open Access Journals (Sweden)

    Sanneke van Asselen

    Full Text Available Meta-analysis of case studies has become an important tool for synthesizing case study findings in land change. Meta-analyses of deforestation, urbanization, desertification and change in shifting cultivation systems have been published. This present study adds to this literature, with an analysis of the proximate causes and underlying forces of wetland conversion at a global scale using two complementary approaches of systematic review. Firstly, a meta-analysis of 105 case-study papers describing wetland conversion was performed, showing that different combinations of multiple-factor proximate causes, and underlying forces, drive wetland conversion. Agricultural development has been the main proximate cause of wetland conversion, and economic growth and population density are the most frequently identified underlying forces. Secondly, to add a more quantitative component to the study, a logistic meta-regression analysis was performed to estimate the likelihood of wetland conversion worldwide, using globally-consistent biophysical and socioeconomic location factor maps. Significant factors explaining wetland conversion, in order of importance, are market influence, total wetland area (lower conversion probability, mean annual temperature and cropland or built-up area. The regression analyses results support the outcomes of the meta-analysis of the processes of conversion mentioned in the individual case studies. In o