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  1. 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,

  2. Willems method of dental age estimation in children: A systematic review and meta-analysis.

    Science.gov (United States)

    Sehrawat, J S; Singh, Monika

    2017-11-01

    Age estimation from dental developmental stages is considered comparatively more accurate, reliable and precise than other methods used in forensic sciences. Willems method is the revised version of Demirjian method, based on modified dental maturity scores to estimate age of children in years for both the sexes. To test the applicability and accuracy level of Willems method of dental age estimation in diverse population samples by quantifying the variations between the chronological and estimated ages of an individual. A systematic search of online databases (Pubmed, Scopus, Embase, Medline, Trip and Web of Science) was performed for identifying the articles utilizing Willems dental maturity scaling method for age estimation in children. All the research articles published in peer-reviewed English language journals between 2001 and January 2017 were included for present systematic review and meta-analysis. Out of the total 973 selected articles; thirty one studies were recruited for qualitative analysis and out of them, 15 studies were selected/identified for quantitative and meta-analysis. It was found that Willems method overestimates the age of children to a comparatively lesser extent (-0.04 and -0.02 years) than the Demirjian method (around six months). Willems method of dental age estimation gives comparatively lesser overestimations of age than other methods reported in the available literature and is thus, accurate and reliable enough to be utilized for forensic purposes. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  3. 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.

  4. 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…

  5. Accuracy of peripheral thermometers for estimating temperature: a systematic review and meta-analysis.

    Science.gov (United States)

    Niven, Daniel J; Gaudet, Jonathan E; Laupland, Kevin B; Mrklas, Kelly J; Roberts, Derek J; Stelfox, Henry Thomas

    2015-11-17

    Body temperature is commonly used to screen patients for infectious diseases, establish diagnoses, monitor therapy, and guide management decisions. To determine the accuracy of peripheral thermometers for estimating core body temperature in adults and children. MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and CINAHL Plus from inception to July 2015. Prospective studies comparing the accuracy of peripheral (tympanic membrane, temporal artery, axillary, or oral) thermometers with central (pulmonary artery catheter, urinary bladder, esophageal, or rectal) thermometers. 2 reviewers extracted data on study characteristics, methods, and outcomes and assessed the quality of individual studies. 75 studies (8682 patients) were included. Most studies were at high or unclear risk of patient selection bias (74%) or index test bias (67%). Compared with central thermometers, peripheral thermometers had pooled 95% limits of agreement (random-effects meta-analysis) outside the predefined clinically acceptable range (± 0.5 °C), especially among patients with fever (-1.44 °C to 1.46 °C for adults; -1.49 °C to 0.43 °C for children) and hypothermia (-2.07 °C to 1.90 °C for adults; no data for children). For detection of fever (bivariate random-effects meta-analysis), sensitivity was low (64% [95% CI, 55% to 72%]; I2 = 95.7%; P temperature measurement techniques are limited. Pooled data are associated with interstudy heterogeneity that is not fully explained by stratified and metaregression analyses. Peripheral thermometers do not have clinically acceptable accuracy and should not be used when accurate measurement of body temperature will influence clinical decisions. None.

  6. Estimate of undergraduate university student alcohol use in China: a systematic review and meta-analysis.

    Science.gov (United States)

    Newman, Ian; Ding, Lanyan; Feng, Yonghua

    2017-01-01

    To develop an estimate of self-reported last 30 day alcohol use by university students in China. A search of papers published in English and Chinese between 2006 and 2015, following pre-established selection criteria, identified 30 papers that were included in this meta-analysis. Nine moderator variables were preselected for this analysis. A total of 749 papers were identified in the keyword search, and 30 studies (28 in Chinese, 2 in English) met all selection criteria and were included in the meta-analysis. The self-reported last-30-day alcohol use for undergraduate university students was 66.8% for males and 31.7% for females. Meta-regression identified three moderators associated with the different drinking rates reported: the definition of drinking, the origin of the questionnaire used in the survey, and the geographic region where the survey was conducted. These three moderators explained 56% of the heterogeneity of reported drinking rates for the male students and 47% of the heterogeneity of reported drinking rates for the female students. The results of this meta-analysis provide an estimate of last 30 day alcohol use by university students (age 18-23) and increase our understanding of drinking by young people in China. The meta-analysis suggested three variables that could have affected the results and which are worthy of further study. The discussion places these results in the context of Chinese drinking culture and university life.

  7. Meta-analysis of non-renewable energy resource estimates

    International Nuclear Information System (INIS)

    Dale, Michael

    2012-01-01

    This paper offers a review of estimates of ultimately recoverable resources (URR) of non-renewable energy sources: coal, conventional and unconventional oil, conventional and unconventional gas, and uranium for nuclear fission. There is a large range in the estimates of many of the energy sources, even those that have been utilized for a long time and, as such, should be well understood. If it is assumed that the estimates for each resource are normally distributed, then the total value of ultimately recoverable fossil and fissile energy resources is 70,592 EJ. If, on the other hand, the best fitting distribution from each of the resource estimate populations is used, a the total value is 50,702 EJ, a factor of around 30% smaller. - Highlights: ► Brief introduction to categorization of resources. ► Collated over 380 estimates of ultimately recoverable global resources for all non-renewable energy sources. ► Extensive statistical analysis and distribution fitting conducted. ► Cross-energy source comparison of resource magnitudes.

  8. Criterion-Related Validity of the 20-M Shuttle Run Test for Estimating Cardiorespiratory Fitness: A Meta-Analysis

    OpenAIRE

    Mayorga-Vega, Daniel; Aguilar-Soto, Pablo; Viciana, Jesús

    2015-01-01

    The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in ...

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

    Science.gov (United States)

    Partlett, Christopher; Riley, Richard D

    2017-01-30

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

  10. Neuroimaging of reading intervention: a systematic review and activation likelihood estimate meta-analysis.

    Science.gov (United States)

    Barquero, Laura A; Davis, Nicole; Cutting, Laurie E

    2014-01-01

    A growing number of studies examine instructional training and brain activity. The purpose of this paper is to review the literature regarding neuroimaging of reading intervention, with a particular focus on reading difficulties (RD). To locate relevant studies, searches of peer-reviewed literature were conducted using electronic databases to search for studies from the imaging modalities of fMRI and MEG (including MSI) that explored reading intervention. Of the 96 identified studies, 22 met the inclusion criteria for descriptive analysis. A subset of these (8 fMRI experiments with post-intervention data) was subjected to activation likelihood estimate (ALE) meta-analysis to investigate differences in functional activation following reading intervention. Findings from the literature review suggest differences in functional activation of numerous brain regions associated with reading intervention, including bilateral inferior frontal, superior temporal, middle temporal, middle frontal, superior frontal, and postcentral gyri, as well as bilateral occipital cortex, inferior parietal lobules, thalami, and insulae. Findings from the meta-analysis indicate change in functional activation following reading intervention in the left thalamus, right insula/inferior frontal, left inferior frontal, right posterior cingulate, and left middle occipital gyri. Though these findings should be interpreted with caution due to the small number of studies and the disparate methodologies used, this paper is an effort to synthesize across studies and to guide future exploration of neuroimaging and reading intervention.

  11. Hypnosis and pain perception: An Activation Likelihood Estimation (ALE) meta-analysis of functional neuroimaging studies.

    Science.gov (United States)

    Del Casale, Antonio; Ferracuti, Stefano; Rapinesi, Chiara; De Rossi, Pietro; Angeletti, Gloria; Sani, Gabriele; Kotzalidis, Georgios D; Girardi, Paolo

    2015-12-01

    Several studies reported that hypnosis can modulate pain perception and tolerance by affecting cortical and subcortical activity in brain regions involved in these processes. We conducted an Activation Likelihood Estimation (ALE) meta-analysis on functional neuroimaging studies of pain perception under hypnosis to identify brain activation-deactivation patterns occurring during hypnotic suggestions aiming at pain reduction, including hypnotic analgesic, pleasant, or depersonalization suggestions (HASs). We searched the PubMed, Embase and PsycInfo databases; we included papers published in peer-reviewed journals dealing with functional neuroimaging and hypnosis-modulated pain perception. The ALE meta-analysis encompassed data from 75 healthy volunteers reported in 8 functional neuroimaging studies. HASs during experimentally-induced pain compared to control conditions correlated with significant activations of the right anterior cingulate cortex (Brodmann's Area [BA] 32), left superior frontal gyrus (BA 6), and right insula, and deactivation of right midline nuclei of the thalamus. HASs during experimental pain impact both cortical and subcortical brain activity. The anterior cingulate, left superior frontal, and right insular cortices activation increases could induce a thalamic deactivation (top-down inhibition), which may correlate with reductions in pain intensity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

    DEFF Research Database (Denmark)

    Burgess, Stephen; Thompson, Simon G; Thompson, Grahame

    2010-01-01

    Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context...... of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable....... This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides...

  13. Estimating terrestrial aboveground biomass estimation using lidar remote sensing: a meta-analysis

    Science.gov (United States)

    Zolkos, S. G.; Goetz, S. J.; Dubayah, R.

    2012-12-01

    Estimating biomass of terrestrial vegetation is a rapidly expanding research area, but also a subject of tremendous interest for reducing carbon emissions associated with deforestation and forest degradation (REDD). The accuracy of biomass estimates is important in the context carbon markets emerging under REDD, since areas with more accurate estimates command higher prices, but also for characterizing uncertainty in estimates of carbon cycling and the global carbon budget. There is particular interest in mapping biomass so that carbon stocks and stock changes can be monitored consistently across a range of scales - from relatively small projects (tens of hectares) to national or continental scales - but also so that other benefits of forest conservation can be factored into decision making (e.g. biodiversity and habitat corridors). We conducted an analysis of reported biomass accuracy estimates from more than 60 refereed articles using different remote sensing platforms (aircraft and satellite) and sensor types (optical, radar, lidar), with a particular focus on lidar since those papers reported the greatest efficacy (lowest errors) when used in the a synergistic manner with other coincident multi-sensor measurements. We show systematic differences in accuracy between different types of lidar systems flown on different platforms but, perhaps more importantly, differences between forest types (biomes) and plot sizes used for field calibration and assessment. We discuss these findings in relation to monitoring, reporting and verification under REDD, and also in the context of more systematic assessment of factors that influence accuracy and error estimation.

  14. Statistical methodology for estimating the mean difference in a meta-analysis without study-specific variance information.

    Science.gov (United States)

    Sangnawakij, Patarawan; Böhning, Dankmar; Adams, Stephen; Stanton, Michael; Holling, Heinz

    2017-04-30

    Statistical inference for analyzing the results from several independent studies on the same quantity of interest has been investigated frequently in recent decades. Typically, any meta-analytic inference requires that the quantity of interest is available from each study together with an estimate of its variability. The current work is motivated by a meta-analysis on comparing two treatments (thoracoscopic and open) of congenital lung malformations in young children. Quantities of interest include continuous end-points such as length of operation or number of chest tube days. As studies only report mean values (and no standard errors or confidence intervals), the question arises how meta-analytic inference can be developed. We suggest two methods to estimate study-specific variances in such a meta-analysis, where only sample means and sample sizes are available in the treatment arms. A general likelihood ratio test is derived for testing equality of variances in two groups. By means of simulation studies, the bias and estimated standard error of the overall mean difference from both methodologies are evaluated and compared with two existing approaches: complete study analysis only and partial variance information. The performance of the test is evaluated in terms of type I error. Additionally, we illustrate these methods in the meta-analysis on comparing thoracoscopic and open surgery for congenital lung malformations and in a meta-analysis on the change in renal function after kidney donation. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  15. Meta-analysis of nitrogen balance studies for estimating protein requirements in healthy adults.

    Science.gov (United States)

    Rand, William M; Pellett, Peter L; Young, Vernon R

    2003-01-01

    The most recent international dietary protein recommendations for healthy adults are those developed and proposed by the 1985 FAO/WHO/UNU Joint Expert Consultation. The objective was to analyze available nitrogen balance data to establish new recommendations for the protein required by healthy adults. Data were gathered from published nitrogen balance studies that had as their primary objective either the estimation of basal or maintenance requirements or the testing of the adequacy of specific nitrogen intakes in healthy adults. These data were synthesized to characterize the distribution of individual protein requirements; the effects of climate of the study site, adult age, sex, and dietary protein source on individual requirements; and the midpoint of and the variability between the protein requirements of healthy persons. Data for 235 individual subjects, each studied at >or= 3 test protein intakes, were gathered from 19 studies. The median estimated average requirement (EAR) of nitrogen from these data was 105 mg N x kg(-1) x d(-1). Individual requirements were found to fit a log-normal distribution. The median EAR was estimated as the median of this distribution, 105 mg N x kg(-1) x d(-1), whereas the 97.5th percentile (the recommended dietary allowance; RDA) was estimated from the distribution of the log of the requirement (after correction of the total observed variability to remove within-individual variability) as 132 mg N x kg(-1) x d(-1). No significant differences between the climate of the study site, adult age class, sex, or source of dietary protein were observed, although there was an indication that women might have a lower requirement than do men. This meta-analysis provides new recommendations for dietary reference values, ie, an EAR (median) and RDA (97.5th percentile) for healthy adults of 105 and 132 mg N x kg(-1) x d(-1) (0.65 and 0.83 g good-quality protein x kg(-1) x d(-1)), respectively.

  16. Gray matter atrophy in narcolepsy: An activation likelihood estimation meta-analysis.

    Science.gov (United States)

    Weng, Hsu-Huei; Chen, Chih-Feng; Tsai, Yuan-Hsiung; Wu, Chih-Ying; Lee, Meng; Lin, Yu-Ching; Yang, Cheng-Ta; Tsai, Ying-Huang; Yang, Chun-Yuh

    2015-12-01

    The authors reviewed the literature on the use of voxel-based morphometry (VBM) in narcolepsy magnetic resonance imaging (MRI) studies via the use of a meta-analysis of neuroimaging to identify concordant and specific structural deficits in patients with narcolepsy as compared with healthy subjects. We used PubMed to retrieve articles published between January 2000 and March 2014. The authors included all VBM research on narcolepsy and compared the findings of the studies by using gray matter volume (GMV) or gray matter concentration (GMC) to index differences in gray matter. Stereotactic data were extracted from 8 VBM studies of 149 narcoleptic patients and 162 control subjects. We applied activation likelihood estimation (ALE) technique and found significant regional gray matter reduction in the bilateral hypothalamus, thalamus, globus pallidus, extending to nucleus accumbens (NAcc) and anterior cingulate cortex (ACC), left mid orbital and rectal gyri (BAs 10 and 11), right inferior frontal gyrus (BA 47), and the right superior temporal gyrus (BA 41) in patients with narcolepsy. The significant gray matter deficits in narcoleptic patients occurred in the bilateral hypothalamus and frontotemporal regions, which may be related to the emotional processing abnormalities and orexin/hypocretin pathway common among populations of patients with narcolepsy. Copyright © 2015. Published by Elsevier Ltd.

  17. Criterion-Related Validity of the 20-M Shuttle Run Test for Estimating Cardiorespiratory Fitness: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Daniel Mayorga-Vega, Pablo Aguilar-Soto, Jesús Viciana

    2015-09-01

    Full Text Available The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in the present meta-analysis, a total of 78 correlation values were analyzed. The overall results showed that the performance score of the 20-m shuttle run test had a moderate-to-high criterion-related validity for estimating maximum oxygen uptake (rp = 0.66-0.84, being higher when other variables (e.g. sex, age or body mass were used (rp = 0.78-0.95. The present meta-analysis also showed that the criterion-related validity of Léger’s protocol was statistically higher for adults (rp = 0.94, 0.87-1.00 than for children (rp = 0.78, 0.72-0.85. However, sex and maximum oxygen uptake level do not seem to affect the criterion-related validity values. When an individual’s maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness. In adults the performance score only seems to be a strong estimator of cardiorespiratory fitness, in contrast among children the performance score should be combined with other variables. Nevertheless, as in the application of any physical fitness field test, evaluators must be aware that the performance score of the 20-m shuttle run test is simply an estimation and not a direct measure of cardiorespiratory fitness.

  18. A meta-analysis of neuroimaging studies on divergent thinking using activation likelihood estimation.

    Science.gov (United States)

    Wu, Xin; Yang, Wenjing; Tong, Dandan; Sun, Jiangzhou; Chen, Qunlin; Wei, Dongtao; Zhang, Qinglin; Zhang, Meng; Qiu, Jiang

    2015-07-01

    In this study, an activation likelihood estimation (ALE) meta-analysis was used to conduct a quantitative investigation of neuroimaging studies on divergent thinking. Based on the ALE results, the functional magnetic resonance imaging (fMRI) studies showed that distributed brain regions were more active under divergent thinking tasks (DTTs) than those under control tasks, but a large portion of the brain regions were deactivated. The ALE results indicated that the brain networks of the creative idea generation in DTTs may be composed of the lateral prefrontal cortex, posterior parietal cortex [such as the inferior parietal lobule (BA 40) and precuneus (BA 7)], anterior cingulate cortex (ACC) (BA 32), and several regions in the temporal cortex [such as the left middle temporal gyrus (BA 39), and left fusiform gyrus (BA 37)]. The left dorsolateral prefrontal cortex (BA 46) was related to selecting the loosely and remotely associated concepts and organizing them into creative ideas, whereas the ACC (BA 32) was related to observing and forming distant semantic associations in performing DTTs. The posterior parietal cortex may be involved in the semantic information related to the retrieval and buffering of the formed creative ideas, and several regions in the temporal cortex may be related to the stored long-term memory. In addition, the ALE results of the structural studies showed that divergent thinking was related to the dopaminergic system (e.g., left caudate and claustrum). Based on the ALE results, both fMRI and structural MRI studies could uncover the neural basis of divergent thinking from different aspects (e.g., specific cognitive processing and stable individual difference of cognitive capability). © 2015 Wiley Periodicals, Inc.

  19. Anatomical likelihood estimation meta-analysis of grey and white matter anomalies in autism spectrum disorders

    Directory of Open Access Journals (Sweden)

    Thomas P. DeRamus

    2015-01-01

    Full Text Available Autism spectrum disorders (ASD are characterized by impairments in social communication and restrictive, repetitive behaviors. While behavioral symptoms are well-documented, investigations into the neurobiological underpinnings of ASD have not resulted in firm biomarkers. Variability in findings across structural neuroimaging studies has contributed to difficulty in reliably characterizing the brain morphology of individuals with ASD. These inconsistencies may also arise from the heterogeneity of ASD, and wider age-range of participants included in MRI studies and in previous meta-analyses. To address this, the current study used coordinate-based anatomical likelihood estimation (ALE analysis of 21 voxel-based morphometry (VBM studies examining high-functioning individuals with ASD, resulting in a meta-analysis of 1055 participants (506 ASD, and 549 typically developing individuals. Results consisted of grey, white, and global differences in cortical matter between the groups. Modeled anatomical maps consisting of concentration, thickness, and volume metrics of grey and white matter revealed clusters suggesting age-related decreases in grey and white matter in parietal and inferior temporal regions of the brain in ASD, and age-related increases in grey matter in frontal and anterior-temporal regions. White matter alterations included fiber tracts thought to play key roles in information processing and sensory integration. Many current theories of pathobiology ASD suggest that the brains of individuals with ASD may have less-functional long-range (anterior-to-posterior connections. Our findings of decreased cortical matter in parietal–temporal and occipital regions, and thickening in frontal cortices in older adults with ASD may entail altered cortical anatomy, and neurodevelopmental adaptations.

  20. Noninvasive Tests Do Not Accurately Differentiate Nonalcoholic Steatohepatitis From Simple Steatosis: A Systematic Review and Meta-analysis.

    Science.gov (United States)

    Verhaegh, Pauline; Bavalia, Roisin; Winkens, Bjorn; Masclee, Ad; Jonkers, Daisy; Koek, Ger

    2017-08-22

    Non-alcoholic fatty liver disease is a rapidly increasing health problem. Liver biopsy analysis is the most sensitive test to differentiate between non-alcoholic steatohepatitis (NASH) and simple steatosis (SS), but non-invasive methods are needed. We performed a systematic review and meta-analysis of non-invasive tests for differentiating NASH from SS, focusing on blood markers. We performed a systematic search of the PubMed, Medline and Embase (1990-2016) databases using defined keywords, limited to full-text papers in English and human adults, and identified 2608 articles. Two independent reviewers screened the articles and identified 122 eligible articles that used liver biopsy as reference standard. If at least 2 studies were available, pooled sensitivity (sens p ) and specificity (spec p ) values were determined using the Meta-Analysis Package for R (metafor). In the 122 studies analyzed, 219 different blood markers (107 single markers and 112 scoring systems) were identified to differentiate NASH from simple steatosis, and 22 other diagnostic tests were studied. Markers identified related to several pathophysiological mechanisms. The markers analyzed in the largest proportions of studies were alanine aminotransferase (sens p , 63.5% and spec p , 74.4%) within routine biochemical tests, adiponectin (sensp, 72.0% and spec p , 75.7%) within inflammatory markers, CK18-M30 (sens p , 68.4% and spec p , 74.2%) within markers of cell death or proliferation and homeostatic model assessment of insulin resistance (sens p , 69.0% and spec p , 72.7%) within the metabolic markers. Two scoring systems could also be pooled: the NASH test (differentiated NASH from borderline NASH plus simple steatosis with 22.9% sens p and 95.3% spec p ) and the GlycoNASH test (67.1% sens p and 63.8% spec p ). In the meta-analysis, we found no test to differentiate NASH from SS with a high level of pooled sensitivity and specificity (≥80%). However, some blood markers, when included in

  1. Criterion-Related Validity of Sit-and-Reach Tests for Estimating Hamstring and Lumbar Extensibility: a Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Daniel Mayorga-Vega

    2014-03-01

    Full Text Available The main purpose of the present meta-analysis was to examine the scientific literature on the criterion-related validity of sit-and-reach tests for estimating hamstring and lumbar extensibility. For this purpose relevant studies were searched from seven electronic databases dated up through December 2012. Primary outcomes of criterion-related validity were Pearson´s zero-order correlation coefficients (r between sit-and-reach tests and hamstrings and/or lumbar extensibility criterion measures. Then, from the included studies, the Hunter- Schmidt´s psychometric meta-analysis approach was conducted to estimate population criterion- related validity of sit-and-reach tests. Firstly, the corrected correlation mean (rp, unaffected by statistical artefacts (i.e., sampling error and measurement error, was calculated separately for each sit-and-reach test. Subsequently, the three potential moderator variables (sex of participants, age of participants, and level of hamstring extensibility were examined by a partially hierarchical analysis. Of the 34 studies included in the present meta-analysis, 99 correlations values across eight sit-and-reach tests and 51 across seven sit-and-reach tests were retrieved for hamstring and lumbar extensibility, respectively. The overall results showed that all sit-and-reach tests had a moderate mean criterion-related validity for estimating hamstring extensibility (rp = 0.46-0.67, but they had a low mean for estimating lumbar extensibility (rp = 0. 16-0.35. Generally, females, adults and participants with high levels of hamstring extensibility tended to have greater mean values of criterion-related validity for estimating hamstring extensibility. When the use of angular tests is limited such as in a school setting or in large scale studies, scientists and practitioners could use the sit-and-reach tests as a useful alternative for hamstring extensibility estimation, but not for estimating lumbar extensibility.

  2. Criterion-Related Validity of the 20-M Shuttle Run Test for Estimating Cardiorespiratory Fitness: A Meta-Analysis.

    Science.gov (United States)

    Mayorga-Vega, Daniel; Aguilar-Soto, Pablo; Viciana, Jesús

    2015-09-01

    The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt's psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in the present meta-analysis, a total of 78 correlation values were analyzed. The overall results showed that the performance score of the 20-m shuttle run test had a moderate-to-high criterion-related validity for estimating maximum oxygen uptake (r p = 0.66-0.84), being higher when other variables (e.g. sex, age or body mass) were used (r p = 0.78-0.95). The present meta-analysis also showed that the criterion-related validity of Léger's protocol was statistically higher for adults (r p = 0.94, 0.87-1.00) than for children (r p = 0.78, 0.72-0.85). However, sex and maximum oxygen uptake level do not seem to affect the criterion-related validity values. When an individual's maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness. In adults the performance score only seems to be a strong estimator of cardiorespiratory fitness, in contrast among children the performance score should be combined with other variables. Nevertheless, as in the application of any physical fitness field test, evaluators must be aware that the performance score of the 20-m shuttle run test is simply an estimation and not a direct measure of cardiorespiratory fitness. Key pointsOverall the 20-m shuttle run test has a moderate-to-high mean criterion-related validity for estimating cardiorespiratory fitness.The criterion-related validity of the 20-m shuttle run test is significantly

  3. Criterion-Related Validity of the 20-M Shuttle Run Test for Estimating Cardiorespiratory Fitness: A Meta-Analysis

    Science.gov (United States)

    Mayorga-Vega, Daniel; Aguilar-Soto, Pablo; Viciana, Jesús

    2015-01-01

    The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in the present meta-analysis, a total of 78 correlation values were analyzed. The overall results showed that the performance score of the 20-m shuttle run test had a moderate-to-high criterion-related validity for estimating maximum oxygen uptake (rp = 0.66-0.84), being higher when other variables (e.g. sex, age or body mass) were used (rp = 0.78-0.95). The present meta-analysis also showed that the criterion-related validity of Léger’s protocol was statistically higher for adults (rp = 0.94, 0.87-1.00) than for children (rp = 0.78, 0.72-0.85). However, sex and maximum oxygen uptake level do not seem to affect the criterion-related validity values. When an individual’s maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness. In adults the performance score only seems to be a strong estimator of cardiorespiratory fitness, in contrast among children the performance score should be combined with other variables. Nevertheless, as in the application of any physical fitness field test, evaluators must be aware that the performance score of the 20-m shuttle run test is simply an estimation and not a direct measure of cardiorespiratory fitness. Key points Overall the 20-m shuttle run test has a moderate-to-high mean criterion-related validity for estimating cardiorespiratory fitness. The criterion-related validity of the 20-m shuttle run test is significantly

  4. 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

  5. Criterion-Related Validity of Sit-and-Reach Tests for Estimating Hamstring and Lumbar Extensibility: a Meta-Analysis.

    Science.gov (United States)

    Mayorga-Vega, Daniel; Merino-Marban, Rafael; Viciana, Jesús

    2014-01-01

    The main purpose of the present meta-analysis was to examine the scientific literature on the criterion-related validity of sit-and-reach tests for estimating hamstring and lumbar extensibility. For this purpose relevant studies were searched from seven electronic databases dated up through December 2012. Primary outcomes of criterion-related validity were Pearson´s zero-order correlation coefficients (r) between sit-and-reach tests and hamstrings and/or lumbar extensibility criterion measures. Then, from the included studies, the Hunter- Schmidt´s psychometric meta-analysis approach was conducted to estimate population criterion- related validity of sit-and-reach tests. Firstly, the corrected correlation mean (rp), unaffected by statistical artefacts (i.e., sampling error and measurement error), was calculated separately for each sit-and-reach test. Subsequently, the three potential moderator variables (sex of participants, age of participants, and level of hamstring extensibility) were examined by a partially hierarchical analysis. Of the 34 studies included in the present meta-analysis, 99 correlations values across eight sit-and-reach tests and 51 across seven sit-and-reach tests were retrieved for hamstring and lumbar extensibility, respectively. The overall results showed that all sit-and-reach tests had a moderate mean criterion-related validity for estimating hamstring extensibility (rp = 0.46-0.67), but they had a low mean for estimating lumbar extensibility (rp = 0. 16-0.35). Generally, females, adults and participants with high levels of hamstring extensibility tended to have greater mean values of criterion-related validity for estimating hamstring extensibility. When the use of angular tests is limited such as in a school setting or in large scale studies, scientists and practitioners could use the sit-and-reach tests as a useful alternative for hamstring extensibility estimation, but not for estimating lumbar extensibility. Key PointsOverall sit

  6. META - ANALYSIS

    Directory of Open Access Journals (Sweden)

    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.

  7. Simulation-based estimation of mean and standard deviation for meta-analysis via Approximate Bayesian Computation (ABC).

    Science.gov (United States)

    Kwon, Deukwoo; Reis, Isildinha M

    2015-08-12

    When conducting a meta-analysis of a continuous outcome, estimated means and standard deviations from the selected studies are required in order to obtain an overall estimate of the mean effect and its confidence interval. If these quantities are not directly reported in the publications, they must be estimated from other reported summary statistics, such as the median, the minimum, the maximum, and quartiles. We propose a simulation-based estimation approach using the Approximate Bayesian Computation (ABC) technique for estimating mean and standard deviation based on various sets of summary statistics found in published studies. We conduct a simulation study to compare the proposed ABC method with the existing methods of Hozo et al. (2005), Bland (2015), and Wan et al. (2014). In the estimation of the standard deviation, our ABC method performs better than the other methods when data are generated from skewed or heavy-tailed distributions. The corresponding average relative error (ARE) approaches zero as sample size increases. In data generated from the normal distribution, our ABC performs well. However, the Wan et al. method is best for estimating standard deviation under normal distribution. In the estimation of the mean, our ABC method is best regardless of assumed distribution. ABC is a flexible method for estimating the study-specific mean and standard deviation for meta-analysis, especially with underlying skewed or heavy-tailed distributions. The ABC method can be applied using other reported summary statistics such as the posterior mean and 95 % credible interval when Bayesian analysis has been employed.

  8. Estimating the Medical Care Costs of Obesity in the United States: Systematic Review, Meta-Analysis, and Empirical Analysis.

    Science.gov (United States)

    Kim, David D; Basu, Anirban

    2016-01-01

    The prevalence of adult obesity exceeds 30% in the United States, posing a significant public health concern as well as a substantial financial burden. Although the impact of obesity on medical spending is undeniably significant, the estimated magnitude of the cost of obesity has varied considerably, perhaps driven by different study methodologies. To document variations in study design and methodology in existing literature and to understand the impact of those variations on the estimated costs of obesity. We conducted a systematic review of the twelve recently published articles that reported costs of obesity and performed a meta-analysis to generate a pooled estimate across those studies. Also, we performed an original analysis to understand the impact of different age groups, statistical models, and confounder adjustment on the magnitude of estimated costs using the nationally representative Medical Expenditure Panel Surveys from 2008-2010. We found significant variations among cost estimates in the existing literature. The meta-analysis found that the annual medical spending attributable to an obese individual was $1901 ($1239-$2582) in 2014 USD, accounting for $149.4 billion at the national level. The two most significant drivers of variability in the cost estimates were age groups and adjustment for obesity-related comorbid conditions. It would be important to acknowledge variations in the magnitude of the medical cost of obesity driven by different study design and methodology. Researchers and policy-makers need to be cautious on determining appropriate cost estimates according to their scientific and political questions. Copyright © 2016 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  9. The Bayesian New Statistics: Hypothesis testing, estimation, meta-analysis, and power analysis from a Bayesian perspective.

    Science.gov (United States)

    Kruschke, John K; Liddell, Torrin M

    2018-02-01

    In the practice of data analysis, there is a conceptual distinction between hypothesis testing, on the one hand, and estimation with quantified uncertainty on the other. Among frequentists in psychology, a shift of emphasis from hypothesis testing to estimation has been dubbed "the New Statistics" (Cumming 2014). A second conceptual distinction is between frequentist methods and Bayesian methods. Our main goal in this article is to explain how Bayesian methods achieve the goals of the New Statistics better than frequentist methods. The article reviews frequentist and Bayesian approaches to hypothesis testing and to estimation with confidence or credible intervals. The article also describes Bayesian approaches to meta-analysis, randomized controlled trials, and power analysis.

  10. Accurate estimation of indoor travel times

    DEFF Research Database (Denmark)

    Prentow, Thor Siiger; Blunck, Henrik; Stisen, Allan

    2014-01-01

    The ability to accurately estimate indoor travel times is crucial for enabling improvements within application areas such as indoor navigation, logistics for mobile workers, and facility management. In this paper, we study the challenges inherent in indoor travel time estimation, and we propose...... the InTraTime method for accurately estimating indoor travel times via mining of historical and real-time indoor position traces. The method learns during operation both travel routes, travel times and their respective likelihood---both for routes traveled as well as for sub-routes thereof. In......TraTime allows to specify temporal and other query parameters, such as time-of-day, day-of-week or the identity of the traveling individual. As input the method is designed to take generic position traces and is thus interoperable with a variety of indoor positioning systems. The method's advantages include...

  11. Meta-analysis of amino acid stable nitrogen isotope ratios for estimating trophic position in marine organisms.

    Science.gov (United States)

    Nielsen, Jens M; Popp, Brian N; Winder, Monika

    2015-07-01

    Estimating trophic structures is a common approach used to retrieve information regarding energy pathways, predation, and competition in complex ecosystems. The application of amino acid (AA) compound-specific nitrogen (N) isotope analysis (CSIA) is a relatively new method used to estimate trophic position (TP) and feeding relationships in diverse organisms. Here, we conducted the first meta-analysis of δ(15)N AA values from measurements of 359 marine species covering four trophic levels, and compared TP estimates from AA-CSIA to literature values derived from food items, gut or stomach content analysis. We tested whether the AA trophic enrichment factor (TEF), or the (15)N enrichment among different individual AAs is constant across trophic levels and whether inclusion of δ(15)N values from multiple AAs improves TP estimation. For the TEF of glutamic acid relative to phenylalanine (Phe) we found an average value of 6.6‰ across all taxa, which is significantly lower than the commonly applied 7.6‰. We found that organism feeding ecology influences TEF values of several trophic AAs relative to Phe, with significantly higher TEF values for herbivores compared to omnivores and carnivores, while TEF values were also significantly lower for animals excreting urea compared to ammonium. Based on the comparison of multiple model structures using the metadata of δ(15)N AA values we show that increasing the number of AAs in principle improves precision in TP estimation. This meta-analysis clarifies the advantages and limitations of using individual δ(15)N AA values as tools in trophic ecology and provides a guideline for the future application of AA-CSIA to food web studies.

  12. Advances in the GRADE approach to rate the certainty in estimates from a network meta-analysis.

    Science.gov (United States)

    Brignardello-Petersen, Romina; Bonner, Ashley; Alexander, Paul E; Siemieniuk, Reed A; Furukawa, Toshi A; Rochwerg, Bram; Hazlewood, Glen S; Alhazzani, Waleed; Mustafa, Reem A; Murad, M Hassan; Puhan, Milo A; Schünemann, Holger J; Guyatt, Gordon H

    2018-01-01

    This article describes conceptual advances of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) working group guidance to evaluate the certainty of evidence (confidence in evidence, quality of evidence) from network meta-analysis (NMA). Application of the original GRADE guidance, published in 2014, in a number of NMAs has resulted in advances that strengthen its conceptual basis and make the process more efficient. This guidance will be useful for systematic review authors who aim to assess the certainty of all pairwise comparisons from an NMA and who are familiar with the basic concepts of NMA and the traditional GRADE approach for pairwise meta-analysis. Two principles of the original GRADE NMA guidance are that we need to rate the certainty of the evidence for each pairwise comparison within a network separately and that in doing so we need to consider both the direct and indirect evidence. We present, discuss, and illustrate four conceptual advances: (1) consideration of imprecision is not necessary when rating the direct and indirect estimates to inform the rating of NMA estimates, (2) there is no need to rate the indirect evidence when the certainty of the direct evidence is high and the contribution of the direct evidence to the network estimate is at least as great as that of the indirect evidence, (3) we should not trust a statistical test of global incoherence of the network to assess incoherence at the pairwise comparison level, and (4) in the presence of incoherence between direct and indirect evidence, the certainty of the evidence of each estimate can help decide which estimate to believe. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Estimating the proportion of persons with diabetes developing diabetic retinopathy in India: A systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    A T Jotheeswaran

    2016-01-01

    Full Text Available Background: Available evidence from India shows that the control of diabetes is poor in majority of the population. This escalates the risk of complications. There is no systematic review to estimate the magnitude of diabetic retinopathy (DR in India. Materials and Methods: A systematic literature search was carried out in Ovid Medline and EMBASE databases using Mesh and key search terms. Studies which reported the proportion of people with diabetes with DR in a representative community population were included. Two independent reviewers reviewed all the retrieved publications. Data were extracted using a predefined form. Review Manager software was used to perform meta-analysis to provide a pooled estimate. Studies included were assessed for methodological quality using selected items from the STROBE checklist. Results: Seven studies (1999–2014; n = 8315 persons with diabetes were included in the review. In the meta-analysis, 14.9% (95% confidence interval [CI] 10.7–19.0% of known diabetics aged ≥30 years and 18.1% (95% CI 14.8–21.4 among those aged ≥50 years had DR. Heterogeneity around this estimate ranged from I2= 79–87%. No linear trend was observed between age and the proportion with DR. The overall methodological quality of included studies was moderate. Conclusions: Early detection of DR is currently not prioritized in public health policies for noncommunicable diseases and blindness programs. Methodological issues in studies suggest that the proportion of diabetics with DR is underestimated in the Indian population. Future research should emphasize more robust methodology for assessing diabetes and DR status.

  14. Altered sensorimotor activation patterns in idiopathic dystonia-an activation likelihood estimation meta-analysis of functional brain imaging studies

    DEFF Research Database (Denmark)

    Løkkegaard, Annemette; Herz, Damian M; Haagensen, Brian Numelin

    2016-01-01

    Dystonia is characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements or postures. Functional neuroimaging studies have yielded abnormal task-related sensorimotor activation in dystonia, but the results appear to be rather variable across studies....... Further, study size was usually small including different types of dystonia. Here we performed an activation likelihood estimation (ALE) meta-analysis of functional neuroimaging studies in patients with primary dystonia to test for convergence of dystonia-related alterations in task-related activity...... postcentral gyrus, right superior temporal gyrus and dorsal midbrain. Apart from the midbrain cluster, all between-group differences in task-related activity were retrieved in a sub-analysis including only the 14 studies on patients with focal dystonia. For focal dystonia, an additional cluster of increased...

  15. Lower estimated glomerular filtration rate and higher albuminuria are associated with mortality and end-stage renal disease. A collaborative meta-analysis of kidney disease population cohorts

    DEFF Research Database (Denmark)

    Astor, Brad C; Matsushita, Kunihiro; Gansevoort, Ron T

    2011-01-01

    We studied here the independent associations of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in individuals with chronic kidney disease (CKD). We performed a collaborative meta-analysis of 13 studies totaling 21,688 patients selected...

  16. How accurate is the prevalence of overweight and obesity in children and adolescents derived from self-reported data? A meta-analysis.

    Science.gov (United States)

    He, Jinbo; Cai, Zhihui; Fan, Xitao

    2018-03-08

    The aim of the current meta-analysis was to evaluate the accuracy of using BMI based on self-reported height and weight (BMIsr) to estimate the prevalence of overweight and obesity among children and adolescents. A systematic literature search was conducted to select studies that compared the prevalence rates of overweight and obesity based on BMIsr and BMIm (BMI based on measured height and weight). A random-effect model was assumed to estimate summary prevalence rates and prevalence ratio (PR). Thirty-seven studies were included. The aggregated prevalence of overweight and obesity based on BMIsr (0·190, 95 % CI 0·163, 0·221) was significantly lower than that based on BMIm (0·233, 95 % CI 0·203, 0·265). The pooled mean PR was 0·823 (95 % CI 0·775, 0·875). Moderator analyses showed that the underestimation was related to gender, age, weight status screened (overweight v. obesity) and weight status screening tool. BMIsr may produce less biased results under some conditions than others. Future researchers using BMIsr may consider these findings and avoid the conditions that could lead to more severe underestimation of the prevalence of overweight and obesity among children and adolescents.

  17. Extraction of unadjusted estimates of prognostic association for meta-analysis: simulation methods as good alternatives to trend and direct method estimation.

    Science.gov (United States)

    Pérez, T; McLellan, J; Perera, R

    2017-12-28

    Systematic reviews and meta-analysis are the standard methods to assess the association between prognostic markers and major events/conditions. However, the summary measures reported are not always explicitly presented and therefore different indirect methods of extracting estimates have been proposed. The aim of this study is to present two new alternative methods for obtaining summary statistics to be included in a meta-analysis of prognostic studies based on simulating individual patient data and to compare them with the already known generalized least squares for trend (glst) estimation method and direct method. We have checked the performance of these methods using a between study comparison, including 122 studies, and a within study comparison, based on data from one of the studies. The results obtained in this study show that glst estimation method appears to overestimate the effect size when reported information is incomplete. For the within-study comparison, the closest approximation to the direct estimates was obtained using the approach based on simulating individual patient data. The proposed simulation methods are a good alternative when other well-known indirect methods cannot be used. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. The French-Canadian data set of Demirjian for dental age estimation: a systematic review and meta-analysis.

    Science.gov (United States)

    Jayaraman, Jayakumar; Wong, Hai Ming; King, Nigel M; Roberts, Graham J

    2013-07-01

    Estimation of age of an individual can be performed by evaluating the pattern of dental development. A dataset for age estimation based on the dental maturity of a French-Canadian population was published over 35 years ago and has become the most widely accepted dataset. The applicability of this dataset has been tested on different population groups. To estimate the observed differences between Chronological age (CA) and Dental age (DA) when the French Canadian dataset was used to estimate the age of different population groups. A systematic search of literature for papers utilizing the French Canadian dataset for age estimation was performed. All language articles from PubMed, Embase and Cochrane databases were electronically searched for terms 'Demirjian' and 'Dental age' published between January 1973 and December 2011. A hand search of articles was also conducted. A total of 274 studies were identified from which 34 studies were included for qualitative analysis and 12 studies were included for quantitative assessment and meta-analysis. When synthesizing the estimation results from different population groups, on average, the Demirjian dataset overestimated the age of females by 0.65 years (-0.10 years to +2.82 years) and males by 0.60 years (-0.23 years to +3.04 years). The French Canadian dataset overestimates the age of the subjects by more than six months and hence this dataset should be used only with considerable caution when estimating age of group of subjects of any global population. Copyright © 2013 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

  19. Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

    DEFF Research Database (Denmark)

    Burgess, Stephen; Thompson, Simon G; Thompson, Grahame

    2010-01-01

    Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context...... an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide...... a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes....

  20. Epidemiology of Q fever in Iran: A systematic review and meta-analysis for estimating serological and molecular prevalence

    Directory of Open Access Journals (Sweden)

    Zary Nokhodian

    2017-01-01

    Full Text Available Background: Q fever is endemic in Iran, thus, we conducted a systematic review and meta-analysis on epidemiology of Coxiella burnetii among humans and animals in Iran. Materials and Methods: A systematic search was performed to identify all articles reporting C. burnetii prevalence in Iranian humans or animals, published from January 2000 to January 2015. Data from articles were extracted, and a pooled estimate of prevalence with corresponding 95% confidence interval (CI was calculated using random effect method. Results: In this review, 27 papers were identified. The pooled seroprevalence of Q fever in animals was 27% (CI 95%: 23%–32%. The prevalence was 33% (CI 95%: 22%–45% in goats, 27% (CI 95%: 21%–32% in sheep, and 17% (CI 95%: 5%–28% in cattle. The bacterial DNA was detected in 5% (95% CI: 3%–9% of milk samples, and it was higher in cattle (10%; 95% CI: 6%–16% than sheep (2%; 95% CI: 0–7% and goats (4%; 95% CI: 0–12%. Conclusion:C. burnetii DNA or its antibody has been frequently detected among ruminants. Since these animals can transmit the infection to humans, Q fever could be a potential health problem in Iran.

  1. Depictive and metric body size estimation in anorexia nervosa and bulimia nervosa: A systematic review and meta-analysis.

    Science.gov (United States)

    Mölbert, Simone Claire; Klein, Lukas; Thaler, Anne; Mohler, Betty J; Brozzo, Chiara; Martus, Peter; Karnath, Hans-Otto; Zipfel, Stephan; Giel, Katrin Elisabeth

    2017-11-01

    A distorted representation of one's own body is a diagnostic criterion and core psychopathology of both anorexia nervosa (AN) and bulimia nervosa (BN). Despite recent technical advances in research, it is still unknown whether this body image disturbance is characterized by body dissatisfaction and a low ideal weight and/or includes a distorted perception or processing of body size. In this article, we provide an update and meta-analysis of 42 articles summarizing measures and results for body size estimation (BSE) from 926 individuals with AN, 536 individuals with BN and 1920 controls. We replicate findings that individuals with AN and BN overestimate their body size as compared to controls (ES=0.63). Our meta-regression shows that metric methods (BSE by direct or indirect spatial measures) yield larger effect sizes than depictive methods (BSE by evaluating distorted pictures), and that effect sizes are larger for patients with BN than for patients with AN. To interpret these results, we suggest a revised theoretical framework for BSE that accounts for differences between depictive and metric BSE methods regarding the underlying body representations (conceptual vs. perceptual, implicit vs. explicit). We also discuss clinical implications and argue for the importance of multimethod approaches to investigate body image disturbance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Hepatitis C in HIV-infected individuals: a systematic review and meta-analysis of estimated prevalence in Africa.

    Science.gov (United States)

    Azevedo, Tiago Castro Lopes; Zwahlen, Marcel; Rauch, Andri; Egger, Matthias; Wandeler, Gilles

    2016-01-01

    Although hepatitis C virus (HCV) screening is recommended for all HIV-infected patients initiating antiretroviral therapy, data on epidemiologic characteristics of HCV infection in resource-limited settings are scarce. We searched PubMed and EMBASE for studies assessing the prevalence of HCV infection among HIV-infected individuals in Africa and extracted data on laboratory methods used. Prevalence estimates from individual studies were combined for each country using random-effects meta-analysis. The importance of study design, population and setting as well as type of test (anti-HCV antibody tests and polymerase chain reactions) was examined with meta-regression. Three randomized controlled trials, 28 cohort studies and 121 cross-sectional analyses with 108,180 HIV-infected individuals from 35 countries were included. The majority of data came from outpatient populations (55%), followed by blood donors (15%) and pregnant women (14%). Based on estimates from 159 study populations, anti-HCV positivity prevalence ranged between 3.3% (95% confidence interval (CI) 1.8-4.7) in Southern Africa and 42.3% (95% CI 4.1-80.5) in North Africa. Study design, type of setting and age distribution did not influence this prevalence significantly. The prevalence of replicating HCV infection, estimated from data of 29 cohorts, was 2.0% (95% CI 1.5-2.6). Ten studies from nine countries reported the HCV genotype of 74 samples, 53% were genotype 1, 24% genotype 2, 14% genotype 4 and 9% genotypes 3, 5 or 6. The prevalence of anti-HCV antibodies is high in HIV-infected patients in Africa, but replicating HCV infection is rare and varies widely across countries.

  3. 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...

  4. Reported Estimates of Adverse Pregnancy Outcomes among Women with and without Syphilis: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Qin, Jiabi; Yang, Tubao; Xiao, Shuiyuan; Tan, Hongzhuan; Feng, Tiejian; Fu, Hanlin

    2014-01-01

    Background To estimate probability of adverse pregnancy outcomes (APOs) among women with and without syphilis through a systematic review of published literatures. Methodology/Principal Findings Chinese and English literatures were searched for studies assessing pregnancy outcomes in the presence of maternal syphilis through August 2013. The prevalence estimates were summarized and analyzed by meta-analysis. Fifty-four literatures involving 11398 syphilitic women and 43342 non-syphilitic women were included from 4187 records initially found. Among untreated mothers with syphilis, pooled estimates were 76.8% for all APOs, 36.0% for congenital syphilis, 23.2% for preterm, 23.4% for low birth weight, 26.4% for stillbirth or fetal loss, 14.9% for miscarriage and 16.2% for neonatal deaths. Among syphilitic mother receiving treatment only in the late trimester (>28 weeks), pooled estimates were 64.4% for APOs, 40.6% for congenital syphilis, 17.6% for preterm, 12.4% for low birth weight, and 21.3% for stillbirth or fetal loss. Among syphilitic mothers with high titers (≥1∶8), pooled estimates were 42.8% for all APOs, 25.8% for congenital syphilis, 15.1% for preterm, 9.4% for low birth weight, 14.6% for stillbirth or fetal loss and 16.0% for neonatal deaths. Among non-syphilitic mothers, the pooled estimates were 13.7% for all APOs, 7.2% for preterm birth, 4.5% for low birth weight, 3.7% for stillbirth or fetal loss, 2.3% for miscarriage and 2.0% for neonatal death. Begg's rank correlation test indicated little evidence of publication bias (P>0.10). Substantial heterogeneity was found across studies in the estimates of all adverse outcomes for both women with syphilis (I2 = 93.9%; Psyphilis (I2 = 94.8%; PSyphilis continues to be an important cause of substantial perinatal morbidity and mortality, which reminds that policy-makers charged with resource allocation that the elimination of mother-to-child transmission of syphilis is a public health priority. PMID

  5. Reported estimates of adverse pregnancy outcomes among women with and without syphilis: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jiabi Qin

    Full Text Available To estimate probability of adverse pregnancy outcomes (APOs among women with and without syphilis through a systematic review of published literatures.Chinese and English literatures were searched for studies assessing pregnancy outcomes in the presence of maternal syphilis through August 2013. The prevalence estimates were summarized and analyzed by meta-analysis. Fifty-four literatures involving 11398 syphilitic women and 43342 non-syphilitic women were included from 4187 records initially found. Among untreated mothers with syphilis, pooled estimates were 76.8% for all APOs, 36.0% for congenital syphilis, 23.2% for preterm, 23.4% for low birth weight, 26.4% for stillbirth or fetal loss, 14.9% for miscarriage and 16.2% for neonatal deaths. Among syphilitic mother receiving treatment only in the late trimester (>28 weeks, pooled estimates were 64.4% for APOs, 40.6% for congenital syphilis, 17.6% for preterm, 12.4% for low birth weight, and 21.3% for stillbirth or fetal loss. Among syphilitic mothers with high titers (≥1∶8, pooled estimates were 42.8% for all APOs, 25.8% for congenital syphilis, 15.1% for preterm, 9.4% for low birth weight, 14.6% for stillbirth or fetal loss and 16.0% for neonatal deaths. Among non-syphilitic mothers, the pooled estimates were 13.7% for all APOs, 7.2% for preterm birth, 4.5% for low birth weight, 3.7% for stillbirth or fetal loss, 2.3% for miscarriage and 2.0% for neonatal death. Begg's rank correlation test indicated little evidence of publication bias (P>0.10. Substantial heterogeneity was found across studies in the estimates of all adverse outcomes for both women with syphilis (I2 = 93.9%; P<0.0001 and women without syphilis (I2 = 94.8%; P<0.0001.Syphilis continues to be an important cause of substantial perinatal morbidity and mortality, which reminds that policy-makers charged with resource allocation that the elimination of mother-to-child transmission of syphilis is a public health priority.

  6. Estimating the effect of intimate partner violence on women's use of contraception: a systematic review and meta-analysis.

    Science.gov (United States)

    Maxwell, Lauren; Devries, Karen; Zionts, Danielle; Alhusen, Jeanne L; Campbell, Jacquelyn

    2015-01-01

    Intimate partner violence (IPV) is an important global public health problem. While there is a growing literature on the association between IPV and women's reproductive health (RH) outcomes, most studies are cross-sectional-which weakens inference about the causal effect of IPV on women's RH. This systematic review synthesizes existing evidence from the strongest study designs to estimate the impact of IPV on women's use of contraception. We searched 11 electronic databases from January of 1980 to 3 December 2013 and reviewed reference lists from systematic reviews for studies examining IPV and contraceptive use. To be able to infer causality, we limited our review to studies that had longitudinal measures of either IPV or women's use of contraception. Of the 1,574 articles identified by the search, we included 179 articles in the full text review and extracted data from 12 studies that met our inclusion criteria. We limited the meta-analysis to seven studies that could be classified as subject to low or moderate levels of bias. Women's experience of IPV was associated with a significant reduction in the odds of using contraception (n = 14,866; OR: 0.47; 95% CI: 0.25, 0.85; I2 = 92%; 95% CII2: 87%, 96%). Restricting to studies that measured the effect of IPV on women's use of partner dependent contraceptive methods was associated with a reduction in the heterogeneity of the overall estimate. In the three studies that examined women's likelihood of using male condoms with their partners, experience of IPV was associated with a significant decrease in condom use (OR: 0.48; 95% CIOR: 0.32, 0.72; I2 = 51%; 95% CII2: 0%, 86%). IPV is associated with a reduction in women's use of contraception; women who experience IPV are less likely to report using condoms with their male partners. Family planning and HIV prevention programs should consider women's experiences of IPV.

  7. Estimating the effect of intimate partner violence on women's use of contraception: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Lauren Maxwell

    Full Text Available Intimate partner violence (IPV is an important global public health problem. While there is a growing literature on the association between IPV and women's reproductive health (RH outcomes, most studies are cross-sectional-which weakens inference about the causal effect of IPV on women's RH. This systematic review synthesizes existing evidence from the strongest study designs to estimate the impact of IPV on women's use of contraception.We searched 11 electronic databases from January of 1980 to 3 December 2013 and reviewed reference lists from systematic reviews for studies examining IPV and contraceptive use. To be able to infer causality, we limited our review to studies that had longitudinal measures of either IPV or women's use of contraception.Of the 1,574 articles identified by the search, we included 179 articles in the full text review and extracted data from 12 studies that met our inclusion criteria. We limited the meta-analysis to seven studies that could be classified as subject to low or moderate levels of bias. Women's experience of IPV was associated with a significant reduction in the odds of using contraception (n = 14,866; OR: 0.47; 95% CI: 0.25, 0.85; I2 = 92%; 95% CII2: 87%, 96%. Restricting to studies that measured the effect of IPV on women's use of partner dependent contraceptive methods was associated with a reduction in the heterogeneity of the overall estimate. In the three studies that examined women's likelihood of using male condoms with their partners, experience of IPV was associated with a significant decrease in condom use (OR: 0.48; 95% CIOR: 0.32, 0.72; I2 = 51%; 95% CII2: 0%, 86%.IPV is associated with a reduction in women's use of contraception; women who experience IPV are less likely to report using condoms with their male partners. Family planning and HIV prevention programs should consider women's experiences of IPV.

  8. Nonindustry-sponsored preclinical studies on statins yield greater efficacy estimates than industry-sponsored studies: a meta-analysis.

    Science.gov (United States)

    Krauth, David; Anglemyer, Andrew; Philipps, Rose; Bero, Lisa

    2014-01-01

    Industry-sponsored clinical drug studies are associated with publication of outcomes that favor the sponsor, even when controlling for potential bias in the methods used. However, the influence of sponsorship bias has not been examined in preclinical animal studies. We performed a meta-analysis of preclinical statin studies to determine whether industry sponsorship is associated with either increased effect sizes of efficacy outcomes and/or risks of bias in a cohort of published preclinical statin studies. We searched Medline (January 1966-April 2012) and identified 63 studies evaluating the effects of statins on atherosclerosis outcomes in animals. Two coders independently extracted study design criteria aimed at reducing bias, results for all relevant outcomes, sponsorship source, and investigator financial ties. The I(2) statistic was used to examine heterogeneity. We calculated the standardized mean difference (SMD) for each outcome and pooled data across studies to estimate the pooled average SMD using random effects models. In a priori subgroup analyses, we assessed statin efficacy by outcome measured, sponsorship source, presence or absence of financial conflict information, use of an optimal time window for outcome assessment, accounting for all animals, inclusion criteria, blinding, and randomization. The effect of statins was significantly larger for studies sponsored by nonindustry sources (-1.99; 95% CI -2.68, -1.31) versus studies sponsored by industry (-0.73; 95% CI -1.00, -0.47) (p valuefinancial conflict information, use of an optimal time window for outcome assessment, accounting for all animals, inclusion criteria, blinding, and randomization. Possible reasons for the differences between nonindustry- and industry-sponsored studies, such as selective reporting of outcomes, require further study.

  9. Estimating the prevalence, hospitalisation and mortality from type 2 diabetes mellitus in Nigeria: a systematic review and meta-analysis.

    Science.gov (United States)

    Adeloye, Davies; Ige, Janet O; Aderemi, Adewale V; Adeleye, Ngozi; Amoo, Emmanuel O; Auta, Asa; Oni, Gbolahan

    2017-05-11

    There is not yet a comprehensive evidence-based epidemiological report on type 2 diabetes mellitus (T2DM) in Nigeria. We aimed to estimate country-wide and zonal prevalence, hospitalisation and mortality rates of T2DM in Nigeria. We searched MEDLINE, EMBASE, Global Health, Africa Journals Online (AJOL) and Google Scholar for population and hospital-based studies on T2DM in Nigeria. We conducted a random-effects meta-analysis on extracted crude estimates, and applied a meta-regression epidemiological model, using the United Nations demographics for Nigeria in 1990 and 2015 to determine estimates of diabetes in Nigeria for the two years. 42 studies, with a total population of 91 320, met our selection criteria. Most of the studies selected were of medium quality (90.5%). The age-adjusted prevalence rates of T2DM in Nigeria among persons aged 20-79 years increased from 2.0% (95% CI 1.9% to 2.1%) in 1990 to 5.7% (95% CI 5.5% to 5.8%) in 2015, accounting for over 874 000 and 4.7 million cases, respectively. The pooled prevalence rate of impaired glucose tolerance was 10.0% (95% CI 4.5% to 15.6%), while impaired fasting glucose was 5.8% (95% CI 3.8% to 7.8%). Hospital admission rate for T2DM was 222.6 (95% CI 133.1 to 312.1) per 100 000 population with hyperglycaemic emergencies, diabetic foot and cardiovascular diseases being most common complications. The overall mortality rate was 30.2 (95% CI 14.6 to 45.8) per 100 000 population, with a case fatality rate of 22.0% (95% CI 8.0% to 36.0%). Our findings suggest an increasing burden of T2DM in Nigeria with many persons currently undiagnosed, and few known cases on treatment. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Criterion-Related Validity of the Distance- and Time-Based Walk/Run Field Tests for Estimating Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Mayorga-Vega, Daniel; Bocanegra-Parrilla, Raúl; Ornelas, Martha; Viciana, Jesús

    2016-01-01

    The main purpose of the present meta-analysis was to examine the criterion-related validity of the distance- and time-based walk/run tests for estimating cardiorespiratory fitness among apparently healthy children and adults. Relevant studies were searched from seven electronic bibliographic databases up to August 2015 and through other sources. The Hunter-Schmidt's psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the following walk/run tests: 5,000 m, 3 miles, 2 miles, 3,000 m, 1.5 miles, 1 mile, 1,000 m, ½ mile, 600 m, 600 yd, ¼ mile, 15 min, 12 min, 9 min, and 6 min. From the 123 included studies, a total of 200 correlation values were analyzed. The overall results showed that the criterion-related validity of the walk/run tests for estimating maximum oxygen uptake ranged from low to moderate (rp = 0.42-0.79), with the 1.5 mile (rp = 0.79, 0.73-0.85) and 12 min walk/run tests (rp = 0.78, 0.72-0.83) having the higher criterion-related validity for distance- and time-based field tests, respectively. The present meta-analysis also showed that sex, age and maximum oxygen uptake level do not seem to affect the criterion-related validity of the walk/run tests. When the evaluation of an individual's maximum oxygen uptake attained during a laboratory test is not feasible, the 1.5 mile and 12 min walk/run tests represent useful alternatives for estimating cardiorespiratory fitness. As in the assessment with any physical fitness field test, evaluators must be aware that the performance score of the walk/run field tests is simply an estimation and not a direct measure of cardiorespiratory fitness.

  11. Criterion-Related Validity of the Distance- and Time-Based Walk/Run Field Tests for Estimating Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Daniel Mayorga-Vega

    Full Text Available The main purpose of the present meta-analysis was to examine the criterion-related validity of the distance- and time-based walk/run tests for estimating cardiorespiratory fitness among apparently healthy children and adults.Relevant studies were searched from seven electronic bibliographic databases up to August 2015 and through other sources. The Hunter-Schmidt's psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the following walk/run tests: 5,000 m, 3 miles, 2 miles, 3,000 m, 1.5 miles, 1 mile, 1,000 m, ½ mile, 600 m, 600 yd, ¼ mile, 15 min, 12 min, 9 min, and 6 min.From the 123 included studies, a total of 200 correlation values were analyzed. The overall results showed that the criterion-related validity of the walk/run tests for estimating maximum oxygen uptake ranged from low to moderate (rp = 0.42-0.79, with the 1.5 mile (rp = 0.79, 0.73-0.85 and 12 min walk/run tests (rp = 0.78, 0.72-0.83 having the higher criterion-related validity for distance- and time-based field tests, respectively. The present meta-analysis also showed that sex, age and maximum oxygen uptake level do not seem to affect the criterion-related validity of the walk/run tests.When the evaluation of an individual's maximum oxygen uptake attained during a laboratory test is not feasible, the 1.5 mile and 12 min walk/run tests represent useful alternatives for estimating cardiorespiratory fitness. As in the assessment with any physical fitness field test, evaluators must be aware that the performance score of the walk/run field tests is simply an estimation and not a direct measure of cardiorespiratory fitness.

  12. Criterion-Related Validity of the Distance- and Time-Based Walk/Run Field Tests for Estimating Cardiorespiratory Fitness: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Mayorga-Vega, Daniel; Bocanegra-Parrilla, Raúl; Ornelas, Martha; Viciana, Jesús

    2016-01-01

    Objectives The main purpose of the present meta-analysis was to examine the criterion-related validity of the distance- and time-based walk/run tests for estimating cardiorespiratory fitness among apparently healthy children and adults. Materials and Methods Relevant studies were searched from seven electronic bibliographic databases up to August 2015 and through other sources. The Hunter-Schmidt’s psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the following walk/run tests: 5,000 m, 3 miles, 2 miles, 3,000 m, 1.5 miles, 1 mile, 1,000 m, ½ mile, 600 m, 600 yd, ¼ mile, 15 min, 12 min, 9 min, and 6 min. Results From the 123 included studies, a total of 200 correlation values were analyzed. The overall results showed that the criterion-related validity of the walk/run tests for estimating maximum oxygen uptake ranged from low to moderate (rp = 0.42–0.79), with the 1.5 mile (rp = 0.79, 0.73–0.85) and 12 min walk/run tests (rp = 0.78, 0.72–0.83) having the higher criterion-related validity for distance- and time-based field tests, respectively. The present meta-analysis also showed that sex, age and maximum oxygen uptake level do not seem to affect the criterion-related validity of the walk/run tests. Conclusions When the evaluation of an individual’s maximum oxygen uptake attained during a laboratory test is not feasible, the 1.5 mile and 12 min walk/run tests represent useful alternatives for estimating cardiorespiratory fitness. As in the assessment with any physical fitness field test, evaluators must be aware that the performance score of the walk/run field tests is simply an estimation and not a direct measure of cardiorespiratory fitness. PMID:26987118

  13. 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…

  14. 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…

  15. Accurate hydrocarbon estimates attained with radioactive isotope

    International Nuclear Information System (INIS)

    Hubbard, G.

    1983-01-01

    To make accurate economic evaluations of new discoveries, an oil company needs to know how much gas and oil a reservoir contains. The porous rocks of these reservoirs are not completely filled with gas or oil, but contain a mixture of gas, oil and water. It is extremely important to know what volume percentage of this water--called connate water--is contained in the reservoir rock. The percentage of connate water can be calculated from electrical resistivity measurements made downhole. The accuracy of this method can be improved if a pure sample of connate water can be analyzed or if the chemistry of the water can be determined by conventional logging methods. Because of the similarity of the mud filtrate--the water in a water-based drilling fluid--and the connate water, this is not always possible. If the oil company cannot distinguish between connate water and mud filtrate, its oil-in-place calculations could be incorrect by ten percent or more. It is clear that unless an oil company can be sure that a sample of connate water is pure, or at the very least knows exactly how much mud filtrate it contains, its assessment of the reservoir's water content--and consequently its oil or gas content--will be distorted. The oil companies have opted for the Repeat Formation Tester (RFT) method. Label the drilling fluid with small doses of tritium--a radioactive isotope of hydrogen--and it will be easy to detect and quantify in the sample

  16. A Bayesian Meta-Analysis of the Effect of Alcohol Use on HCV-Treatment Outcomes with a Comparison of Resampling Methods to Assess Uncertainty in Parameter Estimates.

    Energy Technology Data Exchange (ETDEWEB)

    Cauthen, Katherine Regina [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lambert, Gregory Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Finley, Patrick D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ross, David [US Dept. of Veterans Affairs, Washington, DC (United States); Chartier, Maggie [US Dept. of Veterans Affairs, Washington, DC (United States); Davey, Victoria J. [US Dept. of Veterans Affairs, Washington, DC (United States)

    2015-10-01

    There is mounting evidence that alcohol use is significantly linked to lower HCV treatment response rates in interferon-based therapies, though some of the evidence is conflicting. Furthermore, although health care providers recommend reducing or abstaining from alcohol use prior to treatment, many patients do not succeed in doing so. The goal of this meta-analysis was to systematically review and summarize the Englishlanguage literature up through January 30, 2015 regarding the relationship between alcohol use and HCV treatment outcomes, among patients who were not required to abstain from alcohol use in order to receive treatment. Seven pertinent articles studying 1,751 HCV-infected patients were identified. Log-ORs of HCV treatment response for heavy alcohol use and light alcohol use were calculated and compared. We employed a hierarchical Bayesian meta-analytic model to accommodate the small sample size. The summary estimate for the log-OR of HCV treatment response was -0.775 with a 95% credible interval of (-1.397, -0.236). The results of the Bayesian meta-analysis are slightly more conservative compared to those obtained from a boot-strapped, random effects model. We found evidence of heterogeneity (Q = 14.489, p = 0.025), accounting for 60.28% of the variation among log-ORs. Meta-regression to capture the sources of this heterogeneity did not identify any of the covariates investigated as significant. This meta-analysis confirms that heavy alcohol use is associated with decreased HCV treatment response compared to lighter levels of alcohol use. Further research is required to characterize the mechanism by which alcohol use affects HCV treatment response.

  17. Neonatal resuscitation and immediate newborn assessment and stimulation for the prevention of neonatal deaths: a systematic review, meta-analysis and Delphi estimation of mortality effect

    Science.gov (United States)

    2011-01-01

    Background Of 136 million babies born annually, around 10 million require assistance to breathe. Each year 814,000 neonatal deaths result from intrapartum-related events in term babies (previously “birth asphyxia”) and 1.03 million from complications of prematurity. No systematic assessment of mortality reduction from tactile stimulation or resuscitation has been published. Objective To estimate the mortality effect of immediate newborn assessment and stimulation, and basic resuscitation on neonatal deaths due to term intrapartum-related events or preterm birth, for facility and home births. Methods We conducted systematic reviews for studies reporting relevant mortality or morbidity outcomes. Evidence was assessed using GRADE criteria adapted to provide a systematic approach to mortality effect estimates for the Lives Saved Tool (LiST). Meta-analysis was performed if appropriate. For interventions with low quality evidence but strong recommendation for implementation, a Delphi panel was convened to estimate effect size. Results We identified 24 studies of neonatal resuscitation reporting mortality outcomes (20 observational, 2 quasi-experimental, 2 cluster randomized controlled trials), but none of immediate newborn assessment and stimulation alone. A meta-analysis of three facility-based studies examined the effect of resuscitation training on intrapartum-related neonatal deaths (RR= 0.70, 95%CI 0.59-0.84); this estimate was used for the effect of facility-based basic neonatal resuscitation (additional to stimulation). The evidence for preterm mortality effect was low quality and thus expert opinion was sought. In community-based studies, resuscitation training was part of packages with multiple concurrent interventions, and/or studies did not distinguish term intrapartum-related from preterm deaths, hence no meta-analysis was conducted. Our Delphi panel of 18 experts estimated that immediate newborn assessment and stimulation would reduce both intrapartum

  18. What is the most accurate whole-body imaging modality for assessment of local and distant recurrent disease in colorectal cancer? A meta-analysis. Imaging for recurrent colorectal cancer

    International Nuclear Information System (INIS)

    Maas, Monique; Lambregts, Doenja M.J.; Rutten, Iris J.G.; Cappendijk, Vincent C.; Beets-Tan, Regina G.H.; Nelemans, Patty J.; Beets, Geerard L.

    2011-01-01

    The objective of this study was to compare the diagnostic performance of positron emission tomography (PET), PET/CT, CT and MRI as whole-body imaging modalities for the detection of local and/or distant recurrent disease in colorectal cancer (CRC) patients who have a (high) suspicion of recurrent disease, based on clinical findings or rise in carcinoembryonic antigen (CEA). A meta-analysis was undertaken. PubMed and Embase were searched for studies on the accuracy of whole-body imaging for patients with suspected local and/or distant recurrence of their CRC. Additionally, studies had to have included at least 20 patients with CRC and 2 x 2 contingency tables had to be provided or derivable. Articles evaluating only local recurrence or liver metastasis were excluded. Summary receiver-operating characteristic (ROC) curves were constructed from the data on sensitivity and specificity of individual studies and pooled estimates of diagnostic odds ratios (DORs) and areas under the ROC curve (AUCs) were calculated. To test for heterogeneity the Cochran Q test was used. Fourteen observational studies were included which evaluated PET, PET/CT, CT and/or MRI. Study results were available in 12 studies for PET, in 5 studies for CT, in 5 studies for PET/CT and in 1 study for MRI. AUCs for PET, PET/CT and CT were 0.94 (0.90-0.97), 0.94 (0.87-0.98) and 0.83 (0.72-0.90), respectively. In patient based analyses PET/CT had a higher diagnostic performance than PET with an AUC of 0.95 (0.89-0.97) for PET/CT vs 0.92 (0.86-0.96) for PET. Both whole-body PET and PET/CT are very accurate for the detection of local and/or distant recurrent disease in CRC patients with a (high) suspicion of recurrent disease. CT has the lowest diagnostic performance. This difference is probably mainly due to the lower accuracy of CT for detection of extrahepatic metastases (including local recurrence). For clinical practice PET/CT might be the modality of choice when evaluating patients with a (high

  19. What is the most accurate whole-body imaging modality for assessment of local and distant recurrent disease in colorectal cancer? A meta-analysis. Imaging for recurrent colorectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Maas, Monique; Lambregts, Doenja M.J. [Maastricht University Medical Centre, Department of Radiology, Maastricht (Netherlands); Maastricht University Medical Centre, Department of Surgery, Maastricht (Netherlands); Rutten, Iris J.G.; Cappendijk, Vincent C.; Beets-Tan, Regina G.H. [Maastricht University Medical Centre, Department of Radiology, Maastricht (Netherlands); Nelemans, Patty J. [Maastricht University, Department of Epidemiology, Maastricht (Netherlands); Beets, Geerard L. [Maastricht University Medical Centre, Department of Surgery, Maastricht (Netherlands)

    2011-08-15

    The objective of this study was to compare the diagnostic performance of positron emission tomography (PET), PET/CT, CT and MRI as whole-body imaging modalities for the detection of local and/or distant recurrent disease in colorectal cancer (CRC) patients who have a (high) suspicion of recurrent disease, based on clinical findings or rise in carcinoembryonic antigen (CEA). A meta-analysis was undertaken. PubMed and Embase were searched for studies on the accuracy of whole-body imaging for patients with suspected local and/or distant recurrence of their CRC. Additionally, studies had to have included at least 20 patients with CRC and 2 x 2 contingency tables had to be provided or derivable. Articles evaluating only local recurrence or liver metastasis were excluded. Summary receiver-operating characteristic (ROC) curves were constructed from the data on sensitivity and specificity of individual studies and pooled estimates of diagnostic odds ratios (DORs) and areas under the ROC curve (AUCs) were calculated. To test for heterogeneity the Cochran Q test was used. Fourteen observational studies were included which evaluated PET, PET/CT, CT and/or MRI. Study results were available in 12 studies for PET, in 5 studies for CT, in 5 studies for PET/CT and in 1 study for MRI. AUCs for PET, PET/CT and CT were 0.94 (0.90-0.97), 0.94 (0.87-0.98) and 0.83 (0.72-0.90), respectively. In patient based analyses PET/CT had a higher diagnostic performance than PET with an AUC of 0.95 (0.89-0.97) for PET/CT vs 0.92 (0.86-0.96) for PET. Both whole-body PET and PET/CT are very accurate for the detection of local and/or distant recurrent disease in CRC patients with a (high) suspicion of recurrent disease. CT has the lowest diagnostic performance. This difference is probably mainly due to the lower accuracy of CT for detection of extrahepatic metastases (including local recurrence). For clinical practice PET/CT might be the modality of choice when evaluating patients with a (high

  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. Quantifying Accurate Calorie Estimation Using the "Think Aloud" Method

    Science.gov (United States)

    Holmstrup, Michael E.; Stearns-Bruening, Kay; Rozelle, Jeffrey

    2013-01-01

    Objective: Clients often have limited time in a nutrition education setting. An improved understanding of the strategies used to accurately estimate calories may help to identify areas of focused instruction to improve nutrition knowledge. Methods: A "Think Aloud" exercise was recorded during the estimation of calories in a standard dinner meal…

  2. Ultrasound-guided shoulder girdle injections are more accurate and more effective than landmark-guided injections: a systematic review and meta-analysis.

    Science.gov (United States)

    Aly, Abdel-Rahman; Rajasekaran, Sathish; Ashworth, Nigel

    2015-08-01

    To compare the accuracy and efficacy of ultrasound (US)-guided injections versus landmark-guided injections of the subacromial space, biceps tendon sheath, acromioclavicular (AC) joint and glenohumeral (GH) joint. PubMed, Medline and Cochrane libraries were searched up to 31 July 2013. Two independent authors selected and evaluated randomised controlled trials comparing the accuracy and/or efficacy of US versus landmark-guided injection of the shoulder girdle. A meta-analysis of accuracy, pain Visual Analog Scale (VAS), function score and reported adverse events were performed. Four cadaveric studies (300 cadaveric shoulders) and nine live human studies (514 patients) were reviewed. Based on three studies for AC joint, the accuracy of US versus a landmark-guided injection was 93.6% vs 68.2% (p0.05), 86.7% vs 26.7% for the biceps tendon sheath (p<0.05), and 92.5% vs 72.5% for the GH joint (p=0.025). Based on three studies for the subacromial space, the US group had a significantly greater reduction in pain (mean difference (MD)=1.47, 95% CI 1.0 to 1.93), and improvement in function (standardised MD=0.70, 95% CI 0.39 to 1.01) at 6 weeks postinjection. Based on a single study for the biceps tendon sheath, the US group had a significantly greater reduction in pain (MD 1.9, 95% CI 1.2 to 2.6) and improvement in function (MD=10.9, 95% CI 6.57 to 15.23). US-guided injections showed greater accuracy for all shoulder girdle injections, with the exception of the subacromial space. There was improved efficacy for the subacromial space and biceps tendon sheath injections. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  3. Neural signatures of social conformity: A coordinate-based activation likelihood estimation meta-analysis of functional brain imaging studies.

    Science.gov (United States)

    Wu, Haiyan; Luo, Yi; Feng, Chunliang

    2016-12-01

    People often align their behaviors with group opinions, known as social conformity. Many neuroscience studies have explored the neuropsychological mechanisms underlying social conformity. Here we employed a coordinate-based meta-analysis on neuroimaging studies of social conformity with the purpose to reveal the convergence of the underlying neural architecture. We identified a convergence of reported activation foci in regions associated with normative decision-making, including ventral striatum (VS), dorsal posterior medial frontal cortex (dorsal pMFC), and anterior insula (AI). Specifically, consistent deactivation of VS and activation of dorsal pMFC and AI are identified when people's responses deviate from group opinions. In addition, the deviation-related responses in dorsal pMFC predict people's conforming behavioral adjustments. These are consistent with current models that disagreement with others might evoke "error" signals, cognitive imbalance, and/or aversive feelings, which are plausibly detected in these brain regions as control signals to facilitate subsequent conforming behaviors. Finally, group opinions result in altered neural correlates of valuation, manifested as stronger responses of VS to stimuli endorsed than disliked by others. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Neuroanatomical substrates of action perception and understanding: an anatomic likelihood estimation meta-analysis of lesion-symptom mapping studies in brain injured patients.

    Directory of Open Access Journals (Sweden)

    Cosimo eUrgesi

    2014-05-01

    Full Text Available Several neurophysiologic and neuroimaging studies suggested that motor and perceptual systems are tightly linked along a continuum rather than providing segregated mechanisms supporting different functions. Using correlational approaches, these studies demonstrated that action observation activates not only visual but also motor brain regions. On the other hand, brain stimulation and brain lesion evidence allows tackling the critical question of whether our action representations are necessary to perceive and understand others’ actions. In particular, recent neuropsychological studies have shown that patients with temporal, parietal and frontal lesions exhibit a number of possible deficits in the visual perception and the understanding of others’ actions. The specific anatomical substrates of such neuropsychological deficits however are still a matter of debate. Here we review the existing literature on this issue and perform an anatomic likelihood estimation meta-analysis of studies using lesion-symptom mapping methods on the causal relation between brain lesions and non-linguistic action perception and understanding deficits. The meta-analysis encompassed data from 361 patients tested in 11 studies and identified regions in the inferior frontal cortex, the inferior parietal cortex and the middle/superior temporal cortex, whose damage is consistently associated with poor performance in action perception and understanding tasks across studies. Interestingly, these areas correspond to the three nodes of the action observation network that are strongly activated in response to visual action perception in neuroimaging research and that have been targeted in previous brain stimulation studies. Thus, brain lesion mapping research provides converging causal evidence that premotor, parietal and temporal regions play a crucial role in action recognition and understanding.

  5. Zadoff-Chu coded ultrasonic signal for accurate range estimation

    KAUST Repository

    AlSharif, Mohammed H.

    2017-11-02

    This paper presents a new adaptation of Zadoff-Chu sequences for the purpose of range estimation and movement tracking. The proposed method uses Zadoff-Chu sequences utilizing a wideband ultrasonic signal to estimate the range between two devices with very high accuracy and high update rate. This range estimation method is based on time of flight (TOF) estimation using cyclic cross correlation. The system was experimentally evaluated under different noise levels and multi-user interference scenarios. For a single user, the results show less than 7 mm error for 90% of range estimates in a typical indoor environment. Under the interference from three other users, the 90% error was less than 25 mm. The system provides high estimation update rate allowing accurate tracking of objects moving with high speed.

  6. 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

  7. Improving North American forest biomass estimates from literature synthesis and meta-analysis of existing biomass equations

    Science.gov (United States)

    David C. Chojnacky; Jennifer C. Jenkins; Amanda K. Holland

    2009-01-01

    Thousands of published equations purport to estimate biomass of individual trees. These equations are often based on very small samples, however, and can provide widely different estimates for trees of the same species. We addressed this issue in a previous study by devising 10 new equations that estimated total aboveground biomass for all species in North America (...

  8. Estimation of Uterine Size: How Accurate Are We?

    Science.gov (United States)

    Hoke, Tanya P; Vakili, Babak

    To evaluate the accuracy of gynecologic surgeons at estimating uterine dimensions and weight. Six model uteri of various sizes were created to simulate the size and consistency of a uterus and displayed at 3 stations. The visual station (VS) comprised 2 specimens placed on an unmarked table. The laparoscopic station (LS) consisted of 2 model uteri, each placed in a separate simulated abdomen with a 0 degree laparoscope and 2 operative trocars with standard instruments. The blind weight station (BWS) consisted of blind palpation of 2 separately weighted models (heavy model [HM] and light model [LM]). Participants visually estimated the dimensions of each VS and LS models and blindly palpated the BWS models to estimate weight. Participants included 15 residents, 27 attendings, and 6 medical students. There was no difference in estimation accuracy regarding gender and age. For the VS and LS groups, participants underestimated all dimensions (VS variance = -15.0%; P estimation was less accurate than direct vision (P estimating laparoscopic dimensions (-25.8% vs -41.1%; P = 0.0001). All groups overestimated model weights (HM variance, 92.5%; P estimating dimensions and weights. With surgical decisions often predicated on estimates, education is needed to improve estimation methods.

  9. An Accurate Link Correlation Estimator for Improving Wireless Protocol Performance

    Directory of Open Access Journals (Sweden)

    Zhiwei Zhao

    2015-02-01

    Full Text Available Wireless link correlation has shown significant impact on the performance of various sensor network protocols. Many works have been devoted to exploiting link correlation for protocol improvements. However, the effectiveness of these designs heavily relies on the accuracy of link correlation measurement. In this paper, we investigate state-of-the-art link correlation measurement and analyze the limitations of existing works. We then propose a novel lightweight and accurate link correlation estimation (LACE approach based on the reasoning of link correlation formation. LACE combines both long-term and short-term link behaviors for link correlation estimation. We implement LACE as a stand-alone interface in TinyOS and incorporate it into both routing and flooding protocols. Simulation and testbed results show that LACE: (1 achieves more accurate and lightweight link correlation measurements than the state-of-the-art work; and (2 greatly improves the performance of protocols exploiting link correlation.

  10. 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.  .

  11. Global Estimates on the Number of People Blind or Visually Impaired by Diabetic Retinopathy: A Meta-analysis From 1990 to 2010.

    Science.gov (United States)

    Leasher, Janet L; Bourne, Rupert R A; Flaxman, Seth R; Jonas, Jost B; Keeffe, Jill; Naidoo, Kovin; Pesudovs, Konrad; Price, Holly; White, Richard A; Wong, Tien Y; Resnikoff, Serge; Taylor, Hugh R

    2016-09-01

    To estimate global and regional trends from 1990 to 2010 of the prevalence and number of persons visually impaired specifically by diabetic retinopathy (DR), as a complication of the precipitous trends in global diabetes, is fundamental for health planning purposes. The meta-analysis of published population studies from 1990 to 2012 for the Global Burden of Disease Study 2010 (GBD) yielded estimated global regional trends in DR among other causes of moderate and severe vision impairment (MSVI; presenting visual acuity visual acuity visually impaired people, 0.8 million were blind and 3.7 million were visually impaired because of DR, with an alarming increase of 27% and 64%, respectively, spanning the two decades from 1990 to 2010. DR accounted for 2.6% of all blindness in 2010 and 1.9% of all MSVI worldwide, increasing from 2.1% and 1.3%, respectively, in 1990. These figures were lower in regions with younger populations (4%). The number of persons with visual impairment due to DR worldwide is rising and represents an increasing proportion of all blindness/MSVI causes. Age-standardized prevalence of DR-related blindness/MSVI was higher in sub-Saharan Africa and South Asia. One out of 39 blind people had blindness due to DR, and 1 out of 52 visually impaired people had visual impairment due to DR. © 2016 by the American Diabetes Association.

  12. Toward accurate and precise estimates of lion density.

    Science.gov (United States)

    Elliot, Nicholas B; Gopalaswamy, Arjun M

    2017-08-01

    Reliable estimates of animal density are fundamental to understanding ecological processes and population dynamics. Furthermore, their accuracy is vital to conservation because wildlife authorities rely on estimates to make decisions. However, it is notoriously difficult to accurately estimate density for wide-ranging carnivores that occur at low densities. In recent years, significant progress has been made in density estimation of Asian carnivores, but the methods have not been widely adapted to African carnivores, such as lions (Panthera leo). Although abundance indices for lions may produce poor inferences, they continue to be used to estimate density and inform management and policy. We used sighting data from a 3-month survey and adapted a Bayesian spatially explicit capture-recapture (SECR) model to estimate spatial lion density in the Maasai Mara National Reserve and surrounding conservancies in Kenya. Our unstructured spatial capture-recapture sampling design incorporated search effort to explicitly estimate detection probability and density on a fine spatial scale, making our approach robust in the context of varying detection probabilities. Overall posterior mean lion density was estimated to be 17.08 (posterior SD 1.310) lions >1 year old/100 km 2 , and the sex ratio was estimated at 2.2 females to 1 male. Our modeling framework and narrow posterior SD demonstrate that SECR methods can produce statistically rigorous and precise estimates of population parameters, and we argue that they should be favored over less reliable abundance indices. Furthermore, our approach is flexible enough to incorporate different data types, which enables robust population estimates over relatively short survey periods in a variety of systems. Trend analyses are essential to guide conservation decisions but are frequently based on surveys of differing reliability. We therefore call for a unified framework to assess lion numbers in key populations to improve management and

  13. The potential for meta-analysis to support decision analysis in ecology.

    Science.gov (United States)

    Mengersen, Kerrie; MacNeil, M Aaron; Caley, M Julian

    2015-06-01

    Meta-analysis and decision analysis are underpinned by well-developed methods that are commonly applied to a variety of problems and disciplines. While these two fields have been closely linked in some disciplines such as medicine, comparatively little attention has been paid to the potential benefits of linking them in ecology, despite reasonable expectations that benefits would be derived from doing so. Meta-analysis combines information from multiple studies to provide more accurate parameter estimates and to reduce the uncertainty surrounding them. Decision analysis involves selecting among alternative choices using statistical information that helps to shed light on the uncertainties involved. By linking meta-analysis to decision analysis, improved decisions can be made, with quantification of the costs and benefits of alternate decisions supported by a greater density of information. Here, we briefly review concepts of both meta-analysis and decision analysis, illustrating the natural linkage between them and the benefits from explicitly linking one to the other. We discuss some examples in which this linkage has been exploited in the medical arena and how improvements in precision and reduction of structural uncertainty inherent in a meta-analysis can provide substantive improvements to decision analysis outcomes by reducing uncertainty in expected loss and maximising information from across studies. We then argue that these significant benefits could be translated to ecology, in particular to the problem of making optimal ecological decisions in the face of uncertainty. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Accurate photometric redshift probability density estimation - method comparison and application

    Science.gov (United States)

    Rau, Markus Michael; Seitz, Stella; Brimioulle, Fabrice; Frank, Eibe; Friedrich, Oliver; Gruen, Daniel; Hoyle, Ben

    2015-10-01

    We introduce an ordinal classification algorithm for photometric redshift estimation, which significantly improves the reconstruction of photometric redshift probability density functions (PDFs) for individual galaxies and galaxy samples. As a use case we apply our method to CFHTLS galaxies. The ordinal classification algorithm treats distinct redshift bins as ordered values, which improves the quality of photometric redshift PDFs, compared with non-ordinal classification architectures. We also propose a new single value point estimate of the galaxy redshift, which can be used to estimate the full redshift PDF of a galaxy sample. This method is competitive in terms of accuracy with contemporary algorithms, which stack the full redshift PDFs of all galaxies in the sample, but requires orders of magnitude less storage space. The methods described in this paper greatly improve the log-likelihood of individual object redshift PDFs, when compared with a popular neural network code (ANNZ). In our use case, this improvement reaches 50 per cent for high-redshift objects (z ≥ 0.75). We show that using these more accurate photometric redshift PDFs will lead to a reduction in the systematic biases by up to a factor of 4, when compared with less accurate PDFs obtained from commonly used methods. The cosmological analyses we examine and find improvement upon are the following: gravitational lensing cluster mass estimates, modelling of angular correlation functions and modelling of cosmic shear correlation functions.

  15. The Magnitude of Mortality from Ischemic Heart Disease Attributed to Occupational Factors in Korea - Attributable Fraction Estimation Using Meta-analysis

    Directory of Open Access Journals (Sweden)

    Jaehyeok Ha

    2011-03-01

    Conclusion: We estimated occupational IHD mortality of Korea with updated data and more relevant evidence. Despite the efforts to obtain reliable estimates, there were many assumptions and limitations that must be overcome. Future research based on more precise design and reliable evidence is required for more accurate estimates.

  16. 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…

  17. 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...

  18. Accurate position estimation methods based on electrical impedance tomography measurements

    Science.gov (United States)

    Vergara, Samuel; Sbarbaro, Daniel; Johansen, T. A.

    2017-08-01

    than 0.05% of the tomograph radius value. These results demonstrate that the proposed approaches can estimate an object’s position accurately based on EIT measurements if enough process information is available for training or modelling. Since they do not require complex calculations it is possible to use them in real-time applications without requiring high-performance computers.

  19. Accurate position estimation methods based on electrical impedance tomography measurements

    International Nuclear Information System (INIS)

    Vergara, Samuel; Sbarbaro, Daniel; Johansen, T A

    2017-01-01

    than 0.05% of the tomograph radius value. These results demonstrate that the proposed approaches can estimate an object’s position accurately based on EIT measurements if enough process information is available for training or modelling. Since they do not require complex calculations it is possible to use them in real-time applications without requiring high-performance computers. (paper)

  20. Meta-analysis to estimate the load of Leptospira excreted in urine: beyond rats as important sources of transmission in low-income rural communities.

    Science.gov (United States)

    Barragan, Veronica; Nieto, Nathan; Keim, Paul; Pearson, Talima

    2017-01-28

    Leptospirosis is a major zoonotic disease with widespread distribution and a large impact on human health. Carrier animals excrete pathogenic Leptospira primarily in their urine. Infection occurs when the pathogen enters a host through mucosa or small skin abrasions. Humans and other animals are exposed to the pathogen by direct contact with urine, contaminated soil or water. While many factors influence environmental cycling and the transmission of Leptospira to humans, the load of pathogenic Leptospira in the environment is likely to play a major role. Peridomestic rats are often implicated as a potential source of human disease; however exposure to other animals is a risk factor as well. The aim of this report is to highlight the importance of various carrier animals in terms of the quantity of Leptospira shed into the environment. For this, we performed a systematic literature review and a meta-analysis of the amount of pathogen that various animal species shed in their urine. The quantity of pathogen has been reported for cows, deer, dogs, humans, mice, and rats, in a total of 14 research articles. We estimated the average Leptospira per unit volume shed by each animal species, and the daily environmental contribution by considering the total volume of urine excreted by each carrier animal. Rats excrete the highest quantity of Leptospira per millilitre of urine (median = 5.7 × 10 6  cells), but large mammals excrete much more urine and thus shed significantly more Leptospira per day (5.1 × 10 8 to 1.3 × 10 9  cells). Here we illustrate how, in a low-income rural Ecuadorian community, host population demographics, and prevalence of Leptospira infection can be integrated with estimates of shed Leptospira to suggest that peridomestic cattle may be more important than rats in environmental cycling and ultimately, transmission to humans.

  1. A Systematic Review and Meta-Analysis Estimating the Expected Dropout Rates in Randomized Controlled Trials on Yoga Interventions

    Directory of Open Access Journals (Sweden)

    Holger Cramer

    2016-01-01

    Full Text Available A reasonable estimation of expected dropout rates is vital for adequate sample size calculations in randomized controlled trials (RCTs. Underestimating expected dropouts rates increases the risk of false negative results while overestimating rates results in overly large sample sizes, raising both ethical and economic issues. To estimate expected dropout rates in RCTs on yoga interventions, MEDLINE/PubMed, Scopus, IndMED, and the Cochrane Library were searched through February 2014; a total of 168 RCTs were meta-analyzed. Overall dropout rate was 11.42% (95% confidence interval [CI] = 10.11%, 12.73% in the yoga groups; rates were comparable in usual care and psychological control groups and were slightly higher in exercise control groups (rate = 14.53%; 95% CI = 11.56%, 17.50%; odds ratio = 0.82; 95% CI = 0.68, 0.98; p=0.03. For RCTs with durations above 12 weeks, dropout rates in yoga groups increased to 15.23% (95% CI = 11.79%, 18.68%. The upper border of 95% CIs for dropout rates commonly was below 20% regardless of study origin, health condition, gender, age groups, and intervention characteristics; however, it exceeded 40% for studies on HIV patients or heterogeneous age groups. In conclusion, dropout rates can be expected to be less than 15 to 20% for most RCTs on yoga interventions. Yet dropout rates beyond 40% are possible depending on the participants’ sociodemographic and health condition.

  2. 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.

  3. Is there a critical lesion site for unilateral spatial neglect? A meta-analysis using activation likelihood estimation.

    Directory of Open Access Journals (Sweden)

    Pascal eMolenberghs

    2012-04-01

    Full Text Available The critical lesion site responsible for the syndrome of unilateral spatial neglect has been debated for more than a decade. Here we performed an activation likelihood estimation (ALE to provide for the first time an objective quantitative index of the consistency of lesion sites across anatomical group studies of spatial neglect. The analysis revealed several distinct regions in which damage has consistently been associated with spatial neglect symptoms. Lesioned clusters were located in several cortical and subcortical regions of the right hemisphere, including the middle and superior temporal gyrus, inferior parietal lobule, intraparietal sulcus, precuneus, middle occipital gyrus, caudate nucleus and posterior insula, as well as in the white matter pathway corresponding to the posterior part of the superior longitudinal fasciculus. Further analyses suggested that separate lesion sites are associated with impairments in different behavioural tests, such as line bisection and target cancellation. Similarly, specific subcomponents of the heterogeneous neglect syndrome, such as extinction and allocentric and personal neglect, are associated with distinct lesion sites. Future progress in delineating the neuropathological correlates of spatial neglect will depend upon the development of more refined measures of perceptual and cognitive functions than those currently available in the clinical setting.

  4. Different patterns of brain activation in normal aging and Alzheimer's disease from cognitional sight: meta analysis using activation likelihood estimation.

    Science.gov (United States)

    Sadigh-Eteghad, Saeed; Majdi, Alireza; Farhoudi, Mehdi; Talebi, Mahnaz; Mahmoudi, Javad

    2014-08-15

    Alzheimer disease (AD) is a chronic neurological disease, frequently affecting cognitional functions. Recently, a large body of neuro-imaging studies have aimed at finding reliable biomarkers of AD for early diagnosis of disease in contrast with healthy elderlies. We intended to have a meta-analytical study on recent functional neuroimaging studies to find the relationship between cognition in AD patients and normal elderlies. A systematic search was conducted to collect functional neuroimaging studies such as positron emission therapy (PET) and functional magnetic resonance imaging (fMRI) in AD patients and healthy elderlies. The coordinates of regions related to cognition were meta-analyzed using the activation likelihood estimation (ALE) method and Sleuth software. P-value map at the false discovery rate (FDR) of Psize of 200 mm(3) were considered. Data were visualized with MANGO software. Forty-one articles that explored the areas activated during cognition in normal elderly subjects and AD patients were found. According to the findings, left middle frontal gyrus and left precuneus are the most activated areas in cognitional tasks in healthy elderlies and AD patients respectively. In normal elderly subjects and AD patients, comparison of ALE maps and reverse contrast showed that insula and left precuneus were the most activated areas in cognitional aspects respectively. With respect to unification of left precuneus activation in cognitional tasks, it seems that this point can be a hallmark in primary differentiation of AD and healthy individuals. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. 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…

  6. 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…

  7. Accurate orientation estimation using AHRS under conditions of magnetic distortion.

    Science.gov (United States)

    Yadav, Nagesh; Bleakley, Chris

    2014-10-24

    Low cost, compact attitude heading reference systems (AHRS) are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth's magnetic field. However, the Earth's magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g). In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods.

  8. Accurate Orientation Estimation Using AHRS under Conditions of Magnetic Distortion

    Directory of Open Access Journals (Sweden)

    Nagesh Yadav

    2014-10-01

    Full Text Available Low cost, compact attitude heading reference systems (AHRS are now being used to track human body movements in indoor environments by estimation of the 3D orientation of body segments. In many of these systems, heading estimation is achieved by monitoring the strength of the Earth’s magnetic field. However, the Earth’s magnetic field can be locally distorted due to the proximity of ferrous and/or magnetic objects. Herein, we propose a novel method for accurate 3D orientation estimation using an AHRS, comprised of an accelerometer, gyroscope and magnetometer, under conditions of magnetic field distortion. The system performs online detection and compensation for magnetic disturbances, due to, for example, the presence of ferrous objects. The magnetic distortions are detected by exploiting variations in magnetic dip angle, relative to the gravity vector, and in magnetic strength. We investigate and show the advantages of using both magnetic strength and magnetic dip angle for detecting the presence of magnetic distortions. The correction method is based on a particle filter, which performs the correction using an adaptive cost function and by adapting the variance during particle resampling, so as to place more emphasis on the results of dead reckoning of the gyroscope measurements and less on the magnetometer readings. The proposed method was tested in an indoor environment in the presence of various magnetic distortions and under various accelerations (up to 3 g. In the experiments, the proposed algorithm achieves <2° static peak-to-peak error and <5° dynamic peak-to-peak error, significantly outperforming previous methods.

  9. Estimating the Effect of Intimate Partner Violence on Women’s Use of Contraception: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Maxwell, Lauren; Devries, Karen; Zionts, Danielle; Alhusen, Jeanne L.; Campbell, Jacquelyn

    2015-01-01

    Background Intimate partner violence (IPV) is an important global public health problem. While there is a growing literature on the association between IPV and women’s reproductive health (RH) outcomes, most studies are cross-sectional—which weakens inference about the causal effect of IPV on women’s RH. This systematic review synthesizes existing evidence from the strongest study designs to estimate the impact of IPV on women’s use of contraception. Methods We searched 11 electronic databases from January of 1980 to 3 December 2013 and reviewed reference lists from systematic reviews for studies examining IPV and contraceptive use. To be able to infer causality, we limited our review to studies that had longitudinal measures of either IPV or women’s use of contraception. Results Of the 1,574 articles identified by the search, we included 179 articles in the full text review and extracted data from 12 studies that met our inclusion criteria. We limited the meta-analysis to seven studies that could be classified as subject to low or moderate levels of bias. Women’s experience of IPV was associated with a significant reduction in the odds of using contraception (n = 14,866; OR: 0.47; 95% CI: 0.25, 0.85; I2 = 92%; 95% CII2: 87%, 96%). Restricting to studies that measured the effect of IPV on women’s use of partner dependent contraceptive methods was associated with a reduction in the heterogeneity of the overall estimate. In the three studies that examined women’s likelihood of using male condoms with their partners, experience of IPV was associated with a significant decrease in condom use (OR: 0.48; 95% CIOR: 0.32, 0.72; I2 = 51%; 95% CII2: 0%, 86%). Conclusions IPV is associated with a reduction in women’s use of contraception; women who experience IPV are less likely to report using condoms with their male partners. Family planning and HIV prevention programs should consider women’s experiences of IPV. PMID:25693056

  10. Affective value, intensity and quality of liquid tastants/food discernment in the human brain: An activation likelihood estimation meta-analysis.

    Science.gov (United States)

    Yeung, Andy Wai Kan; Goto, Tazuko K; Leung, W Keung

    2018-04-01

    The primary dimensions of taste are affective value, intensity and quality. Numerous studies have reported the role of the insula in evaluating these dimensions of taste; however, the results were inconsistent. Therefore, in the current study, we performed meta-analyses of published data to identify locations consistently activated across studies and evaluate whether different regions of the human brain could be responsible for processing different dimensions of taste. Meta-analyses were performed on 39 experiments, with 846 total healthy subjects (without psychiatric/neurological disorders) in 34 studies reporting whole-brain results. The aim was to establish the activation likelihood estimation (ALE) of taste-mediated regional activation across the whole brain. Apart from one meta-analysis for all studies in general, three analyses were performed to reveal the clusters of activation that were attributable to processing the affective value (data from 323 foci), intensity (data from 43 foci) and quality (data from 45 foci) of taste. The ALE revealed eight clusters of activation outside the insula for processing affective value, covering the middle and posterior cingulate, pre-/post-central gyrus, caudate and thalamus. The affective value had four clusters of activation (two in each hemisphere) in the insula. The intensity and quality activated only the insula, each with one cluster on the right. The concurrence between studies was moderate; at best, 53% of the experiments contributed to the significant clusters attributable to the affective value, 60% to intensity and 50% to quality. The affective value was processed bilaterally in the anterior to middle insula, whereas intensity was processed in the right antero-middle insula, and quality was processed in the right middle insula. The right middle dorsal insula was responsible for processing both the affective value and quality of taste. The exploratory analysis on taste quality did not have a significant result if

  11. 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

  12. BIOACCESSIBILITY TESTS ACCURATELY ESTIMATE BIOAVAILABILITY OF LEAD TO QUAIL

    Science.gov (United States)

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contami...

  13. 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...

  14. Accurate estimates of solutions of second order recursions

    NARCIS (Netherlands)

    Mattheij, R.M.M.

    1975-01-01

    Two important types of two dimensional matrix-vector and second order scalar recursions are studied. Both types possess two kinds of solutions (to be called forward and backward dominant solutions). For the directions of these solutions sharp estimates are derived, from which the solutions

  15. Accurate tempo estimation based on harmonic + noise decomposition

    Science.gov (United States)

    Alonso, Miguel; Richard, Gael; David, Bertrand

    2006-12-01

    We present an innovative tempo estimation system that processes acoustic audio signals and does not use any high-level musical knowledge. Our proposal relies on a harmonic + noise decomposition of the audio signal by means of a subspace analysis method. Then, a technique to measure the degree of musical accentuation as a function of time is developed and separately applied to the harmonic and noise parts of the input signal. This is followed by a periodicity estimation block that calculates the salience of musical accents for a large number of potential periods. Next, a multipath dynamic programming searches among all the potential periodicities for the most consistent prospects through time, and finally the most energetic candidate is selected as tempo. Our proposal is validated using a manually annotated test-base containing 961 music signals from various musical genres. In addition, the performance of the algorithm under different configurations is compared. The robustness of the algorithm when processing signals of degraded quality is also measured.

  16. 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

  17. Bioaccessibility tests accurately estimate bioavailability of lead to quail

    Science.gov (United States)

    Beyer, W. Nelson; Basta, Nicholas T; Chaney, Rufus L.; Henry, Paula F.; Mosby, David; Rattner, Barnett A.; Scheckel, Kirk G.; Sprague, Dan; Weber, John

    2016-01-01

    Hazards of soil-borne Pb to wild birds may be more accurately quantified if the bioavailability of that Pb is known. To better understand the bioavailability of Pb to birds, we measured blood Pb concentrations in Japanese quail (Coturnix japonica) fed diets containing Pb-contaminated soils. Relative bioavailabilities were expressed by comparison with blood Pb concentrations in quail fed a Pb acetate reference diet. Diets containing soil from five Pb-contaminated Superfund sites had relative bioavailabilities from 33%-63%, with a mean of about 50%. Treatment of two of the soils with phosphorus significantly reduced the bioavailability of Pb. Bioaccessibility of Pb in the test soils was then measured in six in vitro tests and regressed on bioavailability. They were: the “Relative Bioavailability Leaching Procedure” (RBALP) at pH 1.5, the same test conducted at pH 2.5, the “Ohio State University In vitro Gastrointestinal” method (OSU IVG), the “Urban Soil Bioaccessible Lead Test”, the modified “Physiologically Based Extraction Test” and the “Waterfowl Physiologically Based Extraction Test.” All regressions had positive slopes. Based on criteria of slope and coefficient of determination, the RBALP pH 2.5 and OSU IVG tests performed very well. Speciation by X-ray absorption spectroscopy demonstrated that, on average, most of the Pb in the sampled soils was sorbed to minerals (30%), bound to organic matter (24%), or present as Pb sulfate (18%). Additional Pb was associated with P (chloropyromorphite, hydroxypyromorphite and tertiary Pb phosphate), and with Pb carbonates, leadhillite (a lead sulfate carbonate hydroxide), and Pb sulfide. The formation of chloropyromorphite reduced the bioavailability of Pb and the amendment of Pb-contaminated soils with P may be a thermodynamically favored means to sequester Pb.

  18. 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

  19. 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

  20. 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. 

  1. Meta-analysis of the INSIG2 association with obesity including 74,345 individuals: does heterogeneity of estimates relate to study design?

    DEFF Research Database (Denmark)

    Heid, Iris M; Huth, Cornelia; Loos, Ruth J F

    2009-01-01

    with subjects selected for conditions related to a better health status ('healthy population', HP), and obesity studies (OB). We tested five hypotheses to explore potential sources of heterogeneity. The meta-analysis of 27 studies on Caucasian adults (n = 66,213) combining the different study designs did......The INSIG2 rs7566605 polymorphism was identified for obesity (BMI> or =30 kg/m(2)) in one of the first genome-wide association studies, but replications were inconsistent. We collected statistics from 34 studies (n = 74,345), including general population (GP) studies, population-based studies...... not support overall association of the CC-genotype with obesity, yielding an odds ratio (OR) of 1.05 (p-value = 0.27). The I(2) measure of 41% (p-value = 0.015) indicated between-study heterogeneity. Restricting to GP studies resulted in a declined I(2) measure of 11% (p-value = 0.33) and an OR of 1.10 (p...

  2. 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.

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

    Science.gov (United States)

    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

  4. 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

  5. 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,.

  6. 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.

  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. Personality Consistency in Dogs: A Meta-Analysis

    Science.gov (United States)

    Fratkin, Jamie L.; Sinn, David L.; Patall, Erika A.; Gosling, Samuel D.

    2013-01-01

    Personality, or consistent individual differences in behavior, is well established in studies of dogs. Such consistency implies predictability of behavior, but some recent research suggests that predictability cannot be assumed. In addition, anecdotally, many dog experts believe that ‘puppy tests’ measuring behavior during the first year of a dog's life are not accurate indicators of subsequent adult behavior. Personality consistency in dogs is an important aspect of human-dog relationships (e.g., when selecting dogs suitable for substance-detection work or placement in a family). Here we perform the first comprehensive meta-analysis of studies reporting estimates of temporal consistency of dog personality. A thorough literature search identified 31 studies suitable for inclusion in our meta-analysis. Overall, we found evidence to suggest substantial consistency (r = 0.43). Furthermore, personality consistency was higher in older dogs, when behavioral assessment intervals were shorter, and when the measurement tool was exactly the same in both assessments. In puppies, aggression and submissiveness were the most consistent dimensions, while responsiveness to training, fearfulness, and sociability were the least consistent dimensions. In adult dogs, there were no dimension-based differences in consistency. There was no difference in personality consistency in dogs tested first as puppies and later as adults (e.g., ‘puppy tests’) versus dogs tested first as puppies and later again as puppies. Finally, there were no differences in consistency between working versus non-working dogs, between behavioral codings versus behavioral ratings, and between aggregate versus single measures. Implications for theory, practice, and future research are discussed. PMID:23372787

  10. Personality consistency in dogs: a meta-analysis.

    Science.gov (United States)

    Fratkin, Jamie L; Sinn, David L; Patall, Erika A; Gosling, Samuel D

    2013-01-01

    Personality, or consistent individual differences in behavior, is well established in studies of dogs. Such consistency implies predictability of behavior, but some recent research suggests that predictability cannot be assumed. In addition, anecdotally, many dog experts believe that 'puppy tests' measuring behavior during the first year of a dog's life are not accurate indicators of subsequent adult behavior. Personality consistency in dogs is an important aspect of human-dog relationships (e.g., when selecting dogs suitable for substance-detection work or placement in a family). Here we perform the first comprehensive meta-analysis of studies reporting estimates of temporal consistency of dog personality. A thorough literature search identified 31 studies suitable for inclusion in our meta-analysis. Overall, we found evidence to suggest substantial consistency (r = 0.43). Furthermore, personality consistency was higher in older dogs, when behavioral assessment intervals were shorter, and when the measurement tool was exactly the same in both assessments. In puppies, aggression and submissiveness were the most consistent dimensions, while responsiveness to training, fearfulness, and sociability were the least consistent dimensions. In adult dogs, there were no dimension-based differences in consistency. There was no difference in personality consistency in dogs tested first as puppies and later as adults (e.g., 'puppy tests') versus dogs tested first as puppies and later again as puppies. Finally, there were no differences in consistency between working versus non-working dogs, between behavioral codings versus behavioral ratings, and between aggregate versus single measures. Implications for theory, practice, and future research are discussed.

  11. Personality consistency in dogs: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Jamie L Fratkin

    Full Text Available Personality, or consistent individual differences in behavior, is well established in studies of dogs. Such consistency implies predictability of behavior, but some recent research suggests that predictability cannot be assumed. In addition, anecdotally, many dog experts believe that 'puppy tests' measuring behavior during the first year of a dog's life are not accurate indicators of subsequent adult behavior. Personality consistency in dogs is an important aspect of human-dog relationships (e.g., when selecting dogs suitable for substance-detection work or placement in a family. Here we perform the first comprehensive meta-analysis of studies reporting estimates of temporal consistency of dog personality. A thorough literature search identified 31 studies suitable for inclusion in our meta-analysis. Overall, we found evidence to suggest substantial consistency (r = 0.43. Furthermore, personality consistency was higher in older dogs, when behavioral assessment intervals were shorter, and when the measurement tool was exactly the same in both assessments. In puppies, aggression and submissiveness were the most consistent dimensions, while responsiveness to training, fearfulness, and sociability were the least consistent dimensions. In adult dogs, there were no dimension-based differences in consistency. There was no difference in personality consistency in dogs tested first as puppies and later as adults (e.g., 'puppy tests' versus dogs tested first as puppies and later again as puppies. Finally, there were no differences in consistency between working versus non-working dogs, between behavioral codings versus behavioral ratings, and between aggregate versus single measures. Implications for theory, practice, and future research are discussed.

  12. Meta-analysis of the INSIG2 association with obesity including 74,345 individuals: does heterogeneity of estimates relate to study design?

    Directory of Open Access Journals (Sweden)

    Iris M Heid

    2009-10-01

    Full Text Available The INSIG2 rs7566605 polymorphism was identified for obesity (BMI> or =30 kg/m(2 in one of the first genome-wide association studies, but replications were inconsistent. We collected statistics from 34 studies (n = 74,345, including general population (GP studies, population-based studies with subjects selected for conditions related to a better health status ('healthy population', HP, and obesity studies (OB. We tested five hypotheses to explore potential sources of heterogeneity. The meta-analysis of 27 studies on Caucasian adults (n = 66,213 combining the different study designs did not support overall association of the CC-genotype with obesity, yielding an odds ratio (OR of 1.05 (p-value = 0.27. The I(2 measure of 41% (p-value = 0.015 indicated between-study heterogeneity. Restricting to GP studies resulted in a declined I(2 measure of 11% (p-value = 0.33 and an OR of 1.10 (p-value = 0.015. Regarding the five hypotheses, our data showed (a some difference between GP and HP studies (p-value = 0.012 and (b an association in extreme comparisons (BMI> or =32.5, 35.0, 37.5, 40.0 kg/m(2 versus BMI<25 kg/m(2 yielding ORs of 1.16, 1.18, 1.22, or 1.27 (p-values 0.001 to 0.003, which was also underscored by significantly increased CC-genotype frequencies across BMI categories (10.4% to 12.5%, p-value for trend = 0.0002. We did not find evidence for differential ORs (c among studies with higher than average obesity prevalence compared to lower, (d among studies with BMI assessment after the year 2000 compared to those before, or (e among studies from older populations compared to younger. Analysis of non-Caucasian adults (n = 4889 or children (n = 3243 yielded ORs of 1.01 (p-value = 0.94 or 1.15 (p-value = 0.22, respectively. There was no evidence for overall association of the rs7566605 polymorphism with obesity. Our data suggested an association with extreme degrees of obesity, and consequently heterogeneous effects from different study designs may

  13. 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…

  14. 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…

  15. A Meta-Analysis of the Effect of Education on Social Capital

    Science.gov (United States)

    Huang, Jian; van den Brink, Henriette Maassen; Groot, Wim

    2009-01-01

    To assess the empirical estimates of the effect of education on social trust and social participation--the basic dimensions of individual social capital--a meta-analysis is applied, synthesizing 154 evaluations on social trust, and 286 evaluations on social participation. The publication bias problem is given special emphasis in the meta-analysis.…

  16. Meta-analysis for heritability estimates of vegetative and reproductive traits of Coffea arabica L.Meta-análise para estimativas de herdabilidade de caracteres vegetativos e reprodutivos de Coffea arabica L.

    Directory of Open Access Journals (Sweden)

    Danielle Pereira Baliza

    2012-08-01

    Full Text Available The compilation of informations resulting from independent studies has been difficulted in almost all scientific fields, mainly due to the great number of scientific papers published in recent years. As a result, summarizing information became a need. In this context, a meta-analysis was conducted with the objective of summarizing the estimates for the heritability for vegetative and reproductive traits of coffee (Coffea arabica L.. Heritability estimates were appraised regarding the following traits: average height of plant, average diameter of the canopy, vegetative vigor, production of processed coffee, yield and rust. The data regarding the heritability estimates are from scientific articles published in national and international journals, congress annals, PhD thesis and Master dissertations. The technique of meta-analysis summarized the estimates heritability from different studies and made possible to conclude that all of the appraised traits are highly inherited, reflecting the great genetic variety of coffee plants, and that is possible to reach satisfactory genetic gains in improvement programs in which those traits are evaluated. A compilação de informações advindas de estudos independentes tem sido dificultada em quase todos os campos da ciência, devido principalmente, ao grande número de trabalhos científicos publicados nos últimos anos. Assim, sumarizar informações tornou-se uma necessidade. Neste contexto, uma meta-análise foi conduzida com o objetivo de sistematizar as estimativas para a herdabilidade de caracteres vegetativos e reprodutivos de cafeeiros (Coffea arabica L.. Foram avaliadas as estimativas de herdabilidade referentes aos seguintes caracteres: altura média da planta, diâmetro médio da copa, vigor vegetativo, produção de café beneficiado, rendimento e resistência a ferrugem. Os dados referentes às estimativas de herdabilidade são provenientes de artigos científicos publicados em revistas

  17. a meta-analysis

    Indian Academy of Sciences (India)

    on self-reported scoliosis from 64,578 monozygotic or dizy- gotic twins from the Swedish twin registry, Grauers et al. (2012) performed the first study of sufficient subjects to cal- culate the heritability estimates of scoliosis and suggested that heritability of AIS was 38%, while the rest, 62% vari- ance in the liability to develop ...

  18. Comparison of type 2 diabetes mellitus incidence in different phases of hepatitis B virus infection: A meta-analysis.

    Science.gov (United States)

    Shen, Yi; Zhang, Sheng; Wang, Xulin; Wang, Yuanyuan; Zhang, Jian; Qin, Gang; Li, Wenchao; Ding, Kun; Zhang, Lei; Liang, Feng

    2017-10-01

    Because whether hepatitis B virus infection increases the risk of type 2 diabetes mellitus has been a controversial topic, pair-wise and network meta-analyses of published literature were carried out to accurately evaluate the association between different phases of hepatitis B virus infection and the risk of type 2 diabetes mellitus. A comprehensive literature retrieval was conducted from the PubMed, Embase, Cochrane Library and Chinese Database to identify epidemiological studies on the association between hepatitis B virus infection and the risk of type 2 diabetes mellitus that were published from 1999 to 2015. A pair-wise meta-analysis of direct evidence was performed to estimate the pooled odds ratios and 95% confidence intervals. A network meta-analysis was conducted, including the construction of a network plot, inconsistency plot, predictive interval plot, comparison-adjusted funnel plot and rank diagram, to graphically link the direct and indirect comparisons between different hepatitis B virus infective phases. Eighteen publications (n=113 639) describing 32 studies were included in this meta-analysis. In the pair-wise meta-analysis, the pooled odds ratio for type 2 diabetes mellitus in chronic hepatitis B cirrhosis patients was 1.76 (95% confidence interval: 1.44-2.14) when compared with non-cirrhotic chronic hepatitis B patients. In the network meta-analysis, six comparisons of four hepatitis B virus infectious states indicated the following descending order for the risk of type 2 diabetes mellitus: hepatitis B cirrhosis patients, non-cirrhotic chronic hepatitis B patients, hepatitis B virus carriers and non-hepatitis B virus controls. This study suggests that hepatitis B virus infection is not an independent risk factor for type 2 diabetes mellitus, but the development of cirrhosis may increase the incidence of type 2 diabetes mellitus cirrhosis. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. 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.

  20. 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.

  1. 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...

  2. 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…

  3. [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,

  4. 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

  5. Estimating Influenza Vaccine Effectiveness With the Test-Negative Design Using Alternative Control Groups: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Feng, Shuo; Cowling, Benjamin J; Kelly, Heath; Sullivan, Sheena G

    2018-02-01

    One important assumption in case-control studies is that control selection should be independent of exposure. Nevertheless, it has been hypothesized that virus interference might lead to a correlation between receipt of influenza vaccination and increased risk of infection with other respiratory viruses. We investigated whether such a phenomenon might affect a study design commonly used to estimate influenza vaccine effectiveness (VE). We searched publications in MEDLINE, PubMed, and Web of Science. We identified 12 studies using the test-negative design (2011-2017) that reported VE estimates separately derived by 3 alternative control groups: 1) all patients testing negative for influenza (FLU), VEFLU-; 2) patients who tested positive for other/another respiratory virus (ORV), VEORV+; and 3) patients who tested negative for all viruses in the panel (PAN), VEPAN-. These included VE estimates from 7 countries for all age groups from 2003/2004 to 2013/2014. We observed no difference in vaccination coverage between the ORV-positive and PAN-negative control groups. A total of 63 VEFLU- estimates, 62 VEORV+ estimates, and 33 VEPAN- estimates were extracted. Pooled estimates of the difference in VE (ΔVE) were very similar between groups. In meta-regression, no association was found between the selection of control group and VE estimates. In conclusion, we did not find any differences in VE estimates based on the choice of control group. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Estimates of possible severe bacterial infection in neonates in sub-Saharan Africa, south Asia, and Latin America for 2012: a systematic review and meta-analysis.

    Science.gov (United States)

    Seale, Anna C; Blencowe, Hannah; Manu, Alexander A; Nair, Harish; Bahl, Rajiv; Qazi, Shamim A; Zaidi, Anita K; Berkley, James A; Cousens, Simon N; Lawn, Joy E

    2014-08-01

    Bacterial infections are a leading cause of the 2·9 million annual neonatal deaths. Treatment is usually based on clinical diagnosis of possible severe bacterial infection (pSBI). To guide programme planning, we have undertaken the first estimates of neonatal pSBI, by sex and by region, for sub-Saharan Africa, south Asia, and Latin America. We included data for pSBI incidence in neonates of 32 weeks' gestation or more (or birthweight ≥1500 g) with livebirth denominator data, undertaking a systematic review and forming an investigator group to obtain unpublished data. We calculated pooled risk estimates for neonatal pSBI and case fatality risk, by sex and by region. We then applied these risk estimates to estimates of livebirths in sub-Saharan Africa, south Asia, and Latin America to estimate cases and associated deaths in 2012. We included data from 22 studies, for 259 944 neonates and 20 196 pSBI cases, with most of the data (18 of the 22 studies) coming from the investigator group. The pooled estimate of pSBI incidence risk was 7·6% (95% CI 6·1-9·2%) and the case-fatality risk associated with pSBI was 9·8% (7·4-12·2). We estimated that in 2012 there were 6·9 million cases (uncertainty range 5·5 million-8·3 million) of pSBI in neonates needing treatment: 3·5 million (2·8 million-4·2 million) in south Asia, 2·6 million (2·1 million-3·1 million) in sub-Saharan Africa, and 0·8 million (0·7 million-1·0 million) in Latin America. The risk of pSBI was greater in boys (risk ratio 1·12, 95% CI 1·06-1·18) than girls. We estimated that there were 0·68 million (0·46 million-0·92 million) neonatal deaths associated with pSBI in 2012. The need-to-treat population for pSBI in these three regions is high, with ten cases of pSBI diagnosed for each associated neonatal death. Deaths and disability can be reduced through improved prevention, detection, and case management. The Wellcome Trust and the Bill & Melinda Gates Foundation through grants to

  7. Evaluating the Quality of Evidence from a Network Meta-Analysis

    Science.gov (United States)

    Salanti, Georgia; Del Giovane, Cinzia; Chaimani, Anna; Caldwell, Deborah M.; Higgins, Julian P. T.

    2014-01-01

    Systematic reviews that collate data about the relative effects of multiple interventions via network meta-analysis are highly informative for decision-making purposes. A network meta-analysis provides two types of findings for a specific outcome: the relative treatment effect for all pairwise comparisons, and a ranking of the treatments. It is important to consider the confidence with which these two types of results can enable clinicians, policy makers and patients to make informed decisions. We propose an approach to determining confidence in the output of a network meta-analysis. Our proposed approach is based on methodology developed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group for pairwise meta-analyses. The suggested framework for evaluating a network meta-analysis acknowledges (i) the key role of indirect comparisons (ii) the contributions of each piece of direct evidence to the network meta-analysis estimates of effect size; (iii) the importance of the transitivity assumption to the validity of network meta-analysis; and (iv) the possibility of disagreement between direct evidence and indirect evidence. We apply our proposed strategy to a systematic review comparing topical antibiotics without steroids for chronically discharging ears with underlying eardrum perforations. The proposed framework can be used to determine confidence in the results from a network meta-analysis. Judgements about evidence from a network meta-analysis can be different from those made about evidence from pairwise meta-analyses. PMID:24992266

  8. 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

  9. 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.

  10. READSCAN: a fast and scalable pathogen discovery program with accurate genome relative abundance estimation.

    Science.gov (United States)

    Naeem, Raeece; Rashid, Mamoon; Pain, Arnab

    2013-02-01

    READSCAN is a highly scalable parallel program to identify non-host sequences (of potential pathogen origin) and estimate their genome relative abundance in high-throughput sequence datasets. READSCAN accurately classified human and viral sequences on a 20.1 million reads simulated dataset in Beowulf compute cluster with 16 nodes (Supplementary Material). http://cbrc.kaust.edu.sa/readscan.

  11. Sample Size Requirements for Accurate Estimation of Squared Semi-Partial Correlation Coefficients.

    Science.gov (United States)

    Algina, James; Moulder, Bradley C.; Moser, Barry K.

    2002-01-01

    Studied the sample size requirements for accurate estimation of squared semi-partial correlation coefficients through simulation studies. Results show that the sample size necessary for adequate accuracy depends on: (1) the population squared multiple correlation coefficient (p squared); (2) the population increase in p squared; and (3) the…

  12. An Accurate FFPA-PSR Estimator Algorithm and Tool for Software Effort Estimation

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Murugesan

    2015-01-01

    Full Text Available Software companies are now keen to provide secure software with respect to accuracy and reliability of their products especially related to the software effort estimation. Therefore, there is a need to develop a hybrid tool which provides all the necessary features. This paper attempts to propose a hybrid estimator algorithm and model which incorporates quality metrics, reliability factor, and the security factor with a fuzzy-based function point analysis. Initially, this method utilizes a fuzzy-based estimate to control the uncertainty in the software size with the help of a triangular fuzzy set at the early development stage. Secondly, the function point analysis is extended by the security and reliability factors in the calculation. Finally, the performance metrics are added with the effort estimation for accuracy. The experimentation is done with different project data sets on the hybrid tool, and the results are compared with the existing models. It shows that the proposed method not only improves the accuracy but also increases the reliability, as well as the security, of the product.

  13. An Accurate FFPA-PSR Estimator Algorithm and Tool for Software Effort Estimation.

    Science.gov (United States)

    Murugesan, Senthil Kumar; Balasubramanian, Chidhambara Rajan

    2015-01-01

    Software companies are now keen to provide secure software with respect to accuracy and reliability of their products especially related to the software effort estimation. Therefore, there is a need to develop a hybrid tool which provides all the necessary features. This paper attempts to propose a hybrid estimator algorithm and model which incorporates quality metrics, reliability factor, and the security factor with a fuzzy-based function point analysis. Initially, this method utilizes a fuzzy-based estimate to control the uncertainty in the software size with the help of a triangular fuzzy set at the early development stage. Secondly, the function point analysis is extended by the security and reliability factors in the calculation. Finally, the performance metrics are added with the effort estimation for accuracy. The experimentation is done with different project data sets on the hybrid tool, and the results are compared with the existing models. It shows that the proposed method not only improves the accuracy but also increases the reliability, as well as the security, of the product.

  14. 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...

  15. Prevalence of human papillomavirus in epithelial ovarian cancer tissue. A meta-analysis of observational studies

    DEFF Research Database (Denmark)

    Svahn, Malene F; Faber, Mette Tuxen; Christensen, Jane

    2014-01-01

    The role of human papillomavirus (HPV) in the pathogenesis of ovarian cancer is controversial, and conflicting results have been published. We conducted a systematic review and meta-analysis to estimate the prevalence of HPV in epithelial ovarian cancer tissue.......The role of human papillomavirus (HPV) in the pathogenesis of ovarian cancer is controversial, and conflicting results have been published. We conducted a systematic review and meta-analysis to estimate the prevalence of HPV in epithelial ovarian cancer tissue....

  16. Accuracy of infrared tympanic thermometry used in the diagnosis of Fever in children: a systematic review and meta-analysis.

    Science.gov (United States)

    Zhen, Chen; Xia, Zhang; Ya Jun, Zhou; Long, Li; Jian, Shuai; Gui Ju, Cai; Long, Li

    2015-02-01

    Accurate determination and detection of fever is essential in the appropriate treatment of pediatric population. It is widely known that improper definitions of fever can cause grave and dangerous consequences in medical procedures. Infrared tympanic thermometry seems a relatively new and popular alternative for traditional measurement in the diagnosis of pediatric fever. However, its accuracy in the diagnosis of fever remains a major concern. Systematic review and meta-analysis. Medline, Ovid, Elsevier, Google Scholar, and Cochrane library. Cross-sectional, prospective design. Two investigators independently assessed selected studies and extracted data. Disagreements were resolved by discussion with other reviewers. A total of 25 articles were included in our meta-analysis. The summary estimates revealed that the pooled sensitivity was 0.70 (95% confidence interval [CI] = 0.68-0.72), pooled specificity was 0.86 (95% CI = 0.85-0.88), and pooled diagnostic odds ratio was 47.3 (95% CI = 29.76-75.18), for the diagnosis of fever using infrared tympanic thermometry. Additionally, the area under the summary receiver operating characteristic curve was 0.94, and Q* value was 0.87. A total of 25 articles that encompassing 31 studies were analyzed. Based on our meta-analysis, accuracy of infrared tympanic thermometry in diagnosing fever is high. We can cautiously make conclusion that infrared tympanic thermometry should be widely used as fever of thermometer. © The Author(s) 2014.

  17. 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

  18. 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…

  19. 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…

  20. 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.

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

    Science.gov (United States)

    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.

  2. The Use of Procalcitonin (PCT) for Diagnosis of Sepsis in Burn Patients: A Meta-Analysis.

    Science.gov (United States)

    Cabral, Luís; Afreixo, Vera; Almeida, Luís; Paiva, José Artur

    2016-01-01

    The continuous development of resuscitation techniques and intensive care reduced the mortality rate induced by the initial shock in burn patients and, currently, infections (especially sepsis) are the main causes of mortality of these patients. The misuse of antimicrobial agents is strongly related to antimicrobial and adverse patient outcomes, development of microbial resistance and increased healthcare-related costs. To overcome these risks, antimicrobial stewardship is mandatory and biomarkers are useful to avoid unnecessary medical prescription, to monitor antimicrobial therapy and to support the decision of its stop. Among a large array of laboratory tests, procalcitonin (PCT) emerged as the leading biomarker to accurately and time-effectively indicate the presence of systemic infection. In the presence of systemic infection, PCT blood levels undergo a sudden and dramatic increase, following the course of the infection, and quickly subside after the control of the septic process. This work is a meta-analysis on PCT performance as a biomarker for sepsis. This meta-analysis showed that overall pooled area under the curve (AUC) is 0.83 (95% CI = 0.76 to 0.90); the estimated cut-off is 1.47 ng/mL. The overall sepsis effect in PCT levels is significant and strong (Cohen's d is 2.1 and 95% CI = 1.1 to 3.2). This meta-analysis showed PCT may be considered as a biomarker with a strong diagnostic ability to discriminate between the septic from the non-septic burn patients. Thus, this work encourages the determination of PCT levels in clinical practice for the management of these patients, in order to timely identify the susceptibility to sepsis and to initiate the antimicrobial therapy, improving the patients' outcomes.

  3. Eddy covariance observations of methane and nitrous oxide emissions. Towards more accurate estimates from ecosystems

    International Nuclear Information System (INIS)

    Kroon, P.S.

    2010-09-01

    About 30% of the increased greenhouse gas (GHG) emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are related to land use changes and agricultural activities. In order to select effective measures, knowledge is required about GHG emissions from these ecosystems and how these emissions are influenced by management and meteorological conditions. Accurate emission values are therefore needed for all three GHGs to compile the full GHG balance. However, the current annual estimates of CH4 and N2O emissions from ecosystems have significant uncertainties, even larger than 50%. The present study showed that an advanced technique, micrometeorological eddy covariance flux technique, could obtain more accurate estimates with uncertainties even smaller than 10%. The current regional and global trace gas flux estimates of CH4 and N2O are possibly seriously underestimated due to incorrect measurement procedures. Accurate measurements of both gases are really important since they could even contribute for more than two-third to the total GHG emission. For example: the total GHG emission of a dairy farm site was estimated at 16.10 3 kg ha -1 yr -1 in CO2-equivalents from which 25% and 45% was contributed by CH4 and N2O, respectively. About 60% of the CH4 emission was emitted by ditches and their bordering edges. These emissions are not yet included in the national inventory reports. We recommend including these emissions in coming reports.

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

    Science.gov (United States)

    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.

  5. Can student health professionals accurately estimate alcohol content in commonly occurring drinks?

    OpenAIRE

    Sinclair, Julia; Searle, Emma

    2016-01-01

    Objectives: Correct identification of alcohol as a contributor to, or comorbidity of, many psychiatric diseases requires health professionals to be competent and confident to take an accurate alcohol history. Being able to estimate (or calculate) the alcohol content in commonly consumed drinks is a prerequisite for quantifying levels of alcohol consumption. The aim of this study was to assess this ability in medical and nursing students.Methods: A cross-sectional survey of 891 medical and nur...

  6. Accurate Estimation of Low Fundamental Frequencies from Real-Valued Measurements

    DEFF Research Database (Denmark)

    Christensen, Mads Græsbøll

    2013-01-01

    In this paper, the difficult problem of estimating low fundamental frequencies from real-valued measurements is addressed. The methods commonly employed do not take the phenomena encountered in this scenario into account and thus fail to deliver accurate estimates. The reason for this is that the......In this paper, the difficult problem of estimating low fundamental frequencies from real-valued measurements is addressed. The methods commonly employed do not take the phenomena encountered in this scenario into account and thus fail to deliver accurate estimates. The reason...... for this is that they employ asymptotic approximations that are violated when the harmonics are not well-separated in frequency, something that happens when the observed signal is real-valued and the fundamental frequency is low. To mitigate this, we analyze the problem and present some exact fundamental frequency estimators...... that are aimed at solving this problem. These esti- mators are based on the principles of nonlinear least-squares, harmonic fitting, optimal filtering, subspace orthogonality, and shift-invariance, and they all reduce to already published methods for a high number of observations. In experiments, the methods...

  7. A method to accurately estimate the muscular torques of human wearing exoskeletons by torque sensors.

    Science.gov (United States)

    Hwang, Beomsoo; Jeon, Doyoung

    2015-04-09

    In exoskeletal robots, the quantification of the user's muscular effort is important to recognize the user's motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users' muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user's limb accurately from the measured torque. The user's limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user's muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions.

  8. A Method to Accurately Estimate the Muscular Torques of Human Wearing Exoskeletons by Torque Sensors

    Directory of Open Access Journals (Sweden)

    Beomsoo Hwang

    2015-04-01

    Full Text Available In exoskeletal robots, the quantification of the user’s muscular effort is important to recognize the user’s motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users’ muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user’s limb accurately from the measured torque. The user’s limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user’s muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions.

  9. A Method to Accurately Estimate the Muscular Torques of Human Wearing Exoskeletons by Torque Sensors

    Science.gov (United States)

    Hwang, Beomsoo; Jeon, Doyoung

    2015-01-01

    In exoskeletal robots, the quantification of the user’s muscular effort is important to recognize the user’s motion intentions and evaluate motor abilities. In this paper, we attempt to estimate users’ muscular efforts accurately using joint torque sensor which contains the measurements of dynamic effect of human body such as the inertial, Coriolis, and gravitational torques as well as torque by active muscular effort. It is important to extract the dynamic effects of the user’s limb accurately from the measured torque. The user’s limb dynamics are formulated and a convenient method of identifying user-specific parameters is suggested for estimating the user’s muscular torque in robotic exoskeletons. Experiments were carried out on a wheelchair-integrated lower limb exoskeleton, EXOwheel, which was equipped with torque sensors in the hip and knee joints. The proposed methods were evaluated by 10 healthy participants during body weight-supported gait training. The experimental results show that the torque sensors are to estimate the muscular torque accurately in cases of relaxed and activated muscle conditions. PMID:25860074

  10. 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

  11. 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.

  12. 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

  13. Validation of the Chinese Version of ID-Migraine in Medical Students and Systematic Review with Meta-Analysis Concerning Its Diagnostic Accuracy.

    Science.gov (United States)

    Wang, Xin; San, Yong Zhi; Sun, Jia Mei; Zhou, Hai Bo; Li, Xin; Zhang, Zuo Ming; Zhao, Ya Shuang; Zhu, Yu Lan

    2015-01-01

    To validate the Chinese version of Migraine Screener (ID-Migraine) in medical students in mainland China and to estimate the diagnostic accuracy of ID-Migraine by means of a systematic review with meta-analysis. A total of 555 medical university students participated in the clinical study. Of these, 190 volunteered to take part in a face-to-face consultation and 365 in a telephone interview to diagnose the presence of migraine according to the criteria of the International Classification of Headache Disorders. The correctness of the diagnosis made clinically and by telephone was assessed by Cohen's kappa statistics. Twenty-two studies were included in the meta-analysis. Sensitivity and specificity were calculated for the clinical study and the meta-analysis. The overall sensitivity and specificity of the Chinese version of ID-Migraine was 84.0% (95% confidence intervals [CI]: 75.0%-90.0%) and 64.0% (95% CI: 59.0%-68.0%), respectively. The Cohen's kappa value of the diagnosis obtained by the face-to-face consultation and the telephone interview was 0.85 (95% CI: 0.69-1.00). A total of 8,682 participants from the 22 studies were included in the meta-analysis. The pooled sensitivity, specificity, and diagnostic odds ratio were 81.0% (95% CI: 80.0%-82.0%), 68.0% (95% CI: 66.0%-69.0%) and 17.03 (95% CI: 9.94-29.18), respectively. The accurate recognition of migraine by the medical students suggests that the Chinese ID-Migraine version is a valid screening tool. In addition the meta-analysis confirmed the high diagnostic accuracy of this screening tool.

  14. 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 ...

  15. Gestational syphilis and stillbirth in the Americas: a systematic review and meta-analysis

    OpenAIRE

    Lauren Arnesen; Suzanne Serruya; Pablo Duran

    2015-01-01

    OBJECTIVE: To perform a systematic review and meta-analysis of reported estimates of the association between gestational syphilis (GS) and stillbirth in the Americas region. METHODS: Cochrane Library, Embase, LILACS, MEDLINE/PubMed, PLOS, and ScienceDirect were searched for original research studies quantifying the relationship between GS and stillbirth in the region. A final sample of eight studies was selected. A cumulative meta-analysis plus four subgroup meta-analyses of study data on the...

  16. Accurate Frequency Estimation Based On Three-Parameter Sine-Fitting With Three FFT Samples

    Directory of Open Access Journals (Sweden)

    Liu Xin

    2015-09-01

    Full Text Available This paper presents a simple DFT-based golden section searching algorithm (DGSSA for the single tone frequency estimation. Because of truncation and discreteness in signal samples, Fast Fourier Transform (FFT and Discrete Fourier Transform (DFT are inevitable to cause the spectrum leakage and fence effect which lead to a low estimation accuracy. This method can improve the estimation accuracy under conditions of a low signal-to-noise ratio (SNR and a low resolution. This method firstly uses three FFT samples to determine the frequency searching scope, then – besides the frequency – the estimated values of amplitude, phase and dc component are obtained by minimizing the least square (LS fitting error of three-parameter sine fitting. By setting reasonable stop conditions or the number of iterations, the accurate frequency estimation can be realized. The accuracy of this method, when applied to observed single-tone sinusoid samples corrupted by white Gaussian noise, is investigated by different methods with respect to the unbiased Cramer-Rao Low Bound (CRLB. The simulation results show that the root mean square error (RMSE of the frequency estimation curve is consistent with the tendency of CRLB as SNR increases, even in the case of a small number of samples. The average RMSE of the frequency estimation is less than 1.5 times the CRLB with SNR = 20 dB and N = 512.

  17. Fast and accurate spectral estimation for online detection of partial broken bar in induction motors

    Science.gov (United States)

    Samanta, Anik Kumar; Naha, Arunava; Routray, Aurobinda; Deb, Alok Kanti

    2018-01-01

    In this paper, an online and real-time system is presented for detecting partial broken rotor bar (BRB) of inverter-fed squirrel cage induction motors under light load condition. This system with minor modifications can detect any fault that affects the stator current. A fast and accurate spectral estimator based on the theory of Rayleigh quotient is proposed for detecting the spectral signature of BRB. The proposed spectral estimator can precisely determine the relative amplitude of fault sidebands and has low complexity compared to available high-resolution subspace-based spectral estimators. Detection of low-amplitude fault components has been improved by removing the high-amplitude fundamental frequency using an extended-Kalman based signal conditioner. Slip is estimated from the stator current spectrum for accurate localization of the fault component. Complexity and cost of sensors are minimal as only a single-phase stator current is required. The hardware implementation has been carried out on an Intel i7 based embedded target ported through the Simulink Real-Time. Evaluation of threshold and detectability of faults with different conditions of load and fault severity are carried out with empirical cumulative distribution function.

  18. 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.

  19. Accurate estimation of the illumination pattern's orientation and wavelength in sinusoidal structured illumination microscopy.

    Science.gov (United States)

    Lahrberg, Marcel; Singh, Mandeep; Khare, Kedar; Ahluwalia, Balpreet Singh

    2018-02-10

    Structured illumination microscopy is able to improve the spatial resolution of wide-field fluorescence imaging by applying sinusoidal stripe pattern illumination to the sample. The corresponding computational image reconstruction requires precise knowledge of the pattern's parameters, which are its phase (ϕ) and wave vector (p). Here, a computationally inexpensive method for estimation of p from the raw data is proposed and illustrated with simulations. The method estimates p through a selective discrete Fourier transform at tunable subpixel precision. This results in an accurate p estimation for all the illumination patterns and subsequently improves the superresolution image recovery by a factor of 10 around sharp edges as compared to an integer pixel approach. The technique as presented here is of major interest to the large variety of custom-build systems that are used. The feasibility of the presented method is proven in comparison with published data.

  20. 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

  1. Extended Kalman Filter with a Fuzzy Method for Accurate Battery Pack State of Charge Estimation

    Directory of Open Access Journals (Sweden)

    Saeed Sepasi

    2015-06-01

    Full Text Available As the world moves toward greenhouse gas reduction, there is increasingly active work around Li-ion chemistry-based batteries as an energy source for electric vehicles (EVs, hybrid electric vehicles (HEVs and smart grids. In these applications, the battery management system (BMS requires an accurate online estimation of the state of charge (SOC in a battery pack. This estimation is difficult, especially after substantial battery aging. In order to address this problem, this paper utilizes SOC estimation of Li-ion battery packs using a fuzzy-improved extended Kalman filter (fuzzy-IEKF for Li-ion cells, regardless of their age. The proposed approach introduces a fuzzy method with a new class and associated membership function that determines an approximate initial value applied to SOC estimation. Subsequently, the EKF method is used by considering the single unit model for the battery pack to estimate the SOC for following periods of battery use. This approach uses an adaptive model algorithm to update the model for each single cell in the battery pack. To verify the accuracy of the estimation method, tests are done on a LiFePO4 aged battery pack consisting of 120 cells connected in series with a nominal voltage of 432 V.

  2. Accurate Lithium-ion battery parameter estimation with continuous-time system identification methods

    International Nuclear Information System (INIS)

    Xia, Bing; Zhao, Xin; Callafon, Raymond de; Garnier, Hugues; Nguyen, Truong; Mi, Chris

    2016-01-01

    Highlights: • Continuous-time system identification is applied in Lithium-ion battery modeling. • Continuous-time and discrete-time identification methods are compared in detail. • The instrumental variable method is employed to further improve the estimation. • Simulations and experiments validate the advantages of continuous-time methods. - Abstract: The modeling of Lithium-ion batteries usually utilizes discrete-time system identification methods to estimate parameters of discrete models. However, in real applications, there is a fundamental limitation of the discrete-time methods in dealing with sensitivity when the system is stiff and the storage resolutions are limited. To overcome this problem, this paper adopts direct continuous-time system identification methods to estimate the parameters of equivalent circuit models for Lithium-ion batteries. Compared with discrete-time system identification methods, the continuous-time system identification methods provide more accurate estimates to both fast and slow dynamics in battery systems and are less sensitive to disturbances. A case of a 2 nd -order equivalent circuit model is studied which shows that the continuous-time estimates are more robust to high sampling rates, measurement noises and rounding errors. In addition, the estimation by the conventional continuous-time least squares method is further improved in the case of noisy output measurement by introducing the instrumental variable method. Simulation and experiment results validate the analysis and demonstrate the advantages of the continuous-time system identification methods in battery applications.

  3. 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...

  4. 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...

  5. 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.

  6. 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.

  7. 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...

  8. 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

  9. Shear-wave elastography contributes to accurate tumour size estimation when assessing small breast cancers.

    Science.gov (United States)

    Mullen, R; Thompson, J M; Moussa, O; Vinnicombe, S; Evans, A

    2014-12-01

    To assess whether the size of peritumoural stiffness (PTS) on shear-wave elastography (SWE) for small primary breast cancers (≤15 mm) was associated with size discrepancies between grey-scale ultrasound (GSUS) and final histological size and whether the addition of PTS size to GSUS size might result in more accurate tumour size estimation when compared to final histological size. A retrospective analysis of 86 consecutive patients between August 2011 and February 2013 who underwent breast-conserving surgery for tumours of size ≤15 mm at ultrasound was carried out. The size of PTS stiffness was compared to mean GSUS size, mean histological size, and the extent of size discrepancy between GSUS and histology. PTS size and GSUS were combined and compared to the final histological size. PTS of >3 mm was associated with a larger mean final histological size (16 versus 11.3 mm, p size of >3 mm was associated with a higher frequency of underestimation of final histological size by GSUS of >5 mm (63% versus 18%, p size led to accurate estimation of the final histological size (p = 0.03). The size of PTS was not associated with margin involvement (p = 0.27). PTS extending beyond 3 mm from the grey-scale abnormality is significantly associated with underestimation of tumour size of >5 mm for small invasive breast cancers. Taking into account the size of PTS also led to accurate estimation of the final histological size. Further studies are required to assess the relationship of the extent of SWE stiffness and margin status. Copyright © 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  10. Motivational interviewing: a systematic review and meta-analysis

    Science.gov (United States)

    Rubak, Sune; Sandbæk, Annelli; Lauritzen, Torsten; Christensen, Bo

    2005-01-01

    Background Motivational Interviewing is a well-known, scientifically tested method of counselling clients developed by Miller and Rollnick and viewed as a useful intervention strategy in the treatment of lifestyle problems and disease. Aim To evaluate the effectiveness of motivational interviewing in different areas of disease and to identify factors shaping outcomes. Design of study A systematic review and meta-analysis of randomised controlled trials using motivational interviewing as the intervention. Method After selection criteria a systematic literature search in 16 databases produced 72 randomised controlled trials the first of which was published in 1991. A quality assessment was made with a validated scale. A meta-analysis was performed as a generic inverse variance meta-analysis. Results Meta-analysis showed a significant effect (95% confidence interval) for motivational interviewing for combined effect estimates for body mass index, total blood cholesterol, systolic blood pressure, blood alcohol concentration and standard ethanol content, while combined effect estimates for cigarettes per day and for HbA1c were not significant. Motivational interviewing had a significant and clinically relevant effect in approximately three out of four studies, with an equal effect on physiological (72%) and psychological (75%) diseases. Psychologists and physicians obtained an effect in approximately 80% of the studies, while other healthcare providers obtained an effect in 46% of the studies. When using motivational interviewing in brief encounters of 15 minutes, 64% of the studies showed an effect. More than one encounter with the patient ensures the effectiveness of motivational interviewing. Conclusion Motivational interviewing in a scientific setting outperforms traditional advice giving in the treatment of a broad range of behavioural problems and diseases. Large-scale studies are now needed to prove that motivational interviewing can be implemented into daily

  11. 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.

  12. 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.

  13. Accurate and quantitative polarization-sensitive OCT by unbiased birefringence estimator with noise-stochastic correction

    Science.gov (United States)

    Kasaragod, Deepa; Sugiyama, Satoshi; Ikuno, Yasushi; Alonso-Caneiro, David; Yamanari, Masahiro; Fukuda, Shinichi; Oshika, Tetsuro; Hong, Young-Joo; Li, En; Makita, Shuichi; Miura, Masahiro; Yasuno, Yoshiaki

    2016-03-01

    Polarization sensitive optical coherence tomography (PS-OCT) is a functional extension of OCT that contrasts the polarization properties of tissues. It has been applied to ophthalmology, cardiology, etc. Proper quantitative imaging is required for a widespread clinical utility. However, the conventional method of averaging to improve the signal to noise ratio (SNR) and the contrast of the phase retardation (or birefringence) images introduce a noise bias offset from the true value. This bias reduces the effectiveness of birefringence contrast for a quantitative study. Although coherent averaging of Jones matrix tomography has been widely utilized and has improved the image quality, the fundamental limitation of nonlinear dependency of phase retardation and birefringence to the SNR was not overcome. So the birefringence obtained by PS-OCT was still not accurate for a quantitative imaging. The nonlinear effect of SNR to phase retardation and birefringence measurement was previously formulated in detail for a Jones matrix OCT (JM-OCT) [1]. Based on this, we had developed a maximum a-posteriori (MAP) estimator and quantitative birefringence imaging was demonstrated [2]. However, this first version of estimator had a theoretical shortcoming. It did not take into account the stochastic nature of SNR of OCT signal. In this paper, we present an improved version of the MAP estimator which takes into account the stochastic property of SNR. This estimator uses a probability distribution function (PDF) of true local retardation, which is proportional to birefringence, under a specific set of measurements of the birefringence and SNR. The PDF was pre-computed by a Monte-Carlo (MC) simulation based on the mathematical model of JM-OCT before the measurement. A comparison between this new MAP estimator, our previous MAP estimator [2], and the standard mean estimator is presented. The comparisons are performed both by numerical simulation and in vivo measurements of anterior and

  14. READSCAN: A fast and scalable pathogen discovery program with accurate genome relative abundance estimation

    KAUST Repository

    Naeem, Raeece

    2012-11-28

    Summary: READSCAN is a highly scalable parallel program to identify non-host sequences (of potential pathogen origin) and estimate their genome relative abundance in high-throughput sequence datasets. READSCAN accurately classified human and viral sequences on a 20.1 million reads simulated dataset in <27 min using a small Beowulf compute cluster with 16 nodes (Supplementary Material). Availability: http://cbrc.kaust.edu.sa/readscan Contact: or raeece.naeem@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online. 2012 The Author(s).

  15. 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

  16. 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.

  17. Threshold Estimation of Generalized Pareto Distribution Based on Akaike Information Criterion for Accurate Reliability Analysis

    International Nuclear Information System (INIS)

    Kang, Seunghoon; Lim, Woochul; Cho, Su-gil; Park, Sanghyun; Lee, Tae Hee; Lee, Minuk; Choi, Jong-su; Hong, Sup

    2015-01-01

    In order to perform estimations with high reliability, it is necessary to deal with the tail part of the cumulative distribution function (CDF) in greater detail compared to an overall CDF. The use of a generalized Pareto distribution (GPD) to model the tail part of a CDF is receiving more research attention with the goal of performing estimations with high reliability. Current studies on GPDs focus on ways to determine the appropriate number of sample points and their parameters. However, even if a proper estimation is made, it can be inaccurate as a result of an incorrect threshold value. Therefore, in this paper, a GPD based on the Akaike information criterion (AIC) is proposed to improve the accuracy of the tail model. The proposed method determines an accurate threshold value using the AIC with the overall samples before estimating the GPD over the threshold. To validate the accuracy of the method, its reliability is compared with that obtained using a general GPD model with an empirical CDF

  18. Accurate Estimation of the Intrinsic Dimension Using Graph Distances: Unraveling the Geometric Complexity of Datasets

    Science.gov (United States)

    Granata, Daniele; Carnevale, Vincenzo

    2016-01-01

    The collective behavior of a large number of degrees of freedom can be often described by a handful of variables. This observation justifies the use of dimensionality reduction approaches to model complex systems and motivates the search for a small set of relevant “collective” variables. Here, we analyze this issue by focusing on the optimal number of variable needed to capture the salient features of a generic dataset and develop a novel estimator for the intrinsic dimension (ID). By approximating geodesics with minimum distance paths on a graph, we analyze the distribution of pairwise distances around the maximum and exploit its dependency on the dimensionality to obtain an ID estimate. We show that the estimator does not depend on the shape of the intrinsic manifold and is highly accurate, even for exceedingly small sample sizes. We apply the method to several relevant datasets from image recognition databases and protein multiple sequence alignments and discuss possible interpretations for the estimated dimension in light of the correlations among input variables and of the information content of the dataset. PMID:27510265

  19. Energy requirements of adult dogs: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Emma N Bermingham

    Full Text Available A meta-analysis was conducted to determine the maintenance energy requirements of adult dogs. Suitable publications were first identified, and then used to generate relationships amongst energy requirements, husbandry, activity level, methodology, sex, neuter status, dog size, and age in healthy adult dogs. Allometric equations for maintenance energy requirements were determined using log-log linear regression. So that the resulting equations could readily be compared with equations reported by the National Research Council, maintenance energy requirements in the current study were determined in kcal/kg(0.75 body weight (BW. Ultimately, the data of 70 treatment groups from 29 publications were used, and mean (± standard deviation maintenance energy requirements were 142.8±55.3 kcal·kgBW(-0.75·day(-1. The corresponding allometric equation was 81.5 kcal·kgBW(-0.9·day(-1 (adjusted R2 = 0.64; 70 treatment groups. Type of husbandry had a significant effect on maintenance energy requirements (P<0.001: requirements were greatest in racing dogs, followed by working dogs and hunting dogs, whilst the energy requirements of pet dogs and kennel dogs were least. Maintenance energy requirements were less in neutered compared with sexually intact dogs (P<0.001, but there was no effect of sex. Further, reported activity level tended to effect the maintenance energy requirement of the dog (P = 0.09. This review suggests that estimating maintenance energy requirements based on BW alone may not be accurate, but that predictions that factor in husbandry, neuter status and, possibly, activity level might be superior. Additionally, more information on the nutrient requirements of older dogs, and those at the extremes of body size (i.e. giant and toy breeds is needed.

  20. Energy Requirements of Adult Dogs: A Meta-Analysis

    Science.gov (United States)

    Bermingham, Emma N.; Thomas, David G.; Cave, Nicholas J.; Morris, Penelope J.; Butterwick, Richard F.; German, Alexander J.

    2014-01-01

    A meta-analysis was conducted to determine the maintenance energy requirements of adult dogs. Suitable publications were first identified, and then used to generate relationships amongst energy requirements, husbandry, activity level, methodology, sex, neuter status, dog size, and age in healthy adult dogs. Allometric equations for maintenance energy requirements were determined using log-log linear regression. So that the resulting equations could readily be compared with equations reported by the National Research Council, maintenance energy requirements in the current study were determined in kcal/kg0.75 body weight (BW). Ultimately, the data of 70 treatment groups from 29 publications were used, and mean (± standard deviation) maintenance energy requirements were 142.8±55.3 kcal.kgBW−0.75.day−1. The corresponding allometric equation was 81.5 kcal.kgBW−0.93.day−1 (adjusted R2 = 0.64; 70 treatment groups). Type of husbandry had a significant effect on maintenance energy requirements (P<0.001): requirements were greatest in racing dogs, followed by working dogs and hunting dogs, whilst the energy requirements of pet dogs and kennel dogs were least. Maintenance energy requirements were less in neutered compared with sexually intact dogs (P<0.001), but there was no effect of sex. Further, reported activity level tended to effect the maintenance energy requirement of the dog (P = 0.09). This review suggests that estimating maintenance energy requirements based on BW alone may not be accurate, but that predictions that factor in husbandry, neuter status and, possibly, activity level might be superior. Additionally, more information on the nutrient requirements of older dogs, and those at the extremes of body size (i.e. giant and toy breeds) is needed. PMID:25313818

  1. 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.

  2. 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 other meta-analyses of land change, similar factors (e.g., agricultural development, population growth, market/economic factors are also identified as important causes of various types of land change (e.g., deforestation, desertification. Meta-analysis helps to identify commonalities across the various local case studies and identify which variables may lead to individual cases to behave differently. The meta-regression provides maps indicating the likelihood of wetland conversion worldwide based on the location factors that have

  3. How accurate is size-specific dose estimate in pediatric body CT examinations?

    Science.gov (United States)

    Karmazyn, Boaz; Ai, Huisi; Klahr, Paul; Ouyang, Fangqian; Jennings, S Gregory

    2016-08-01

    Size-specific dose estimate is gaining increased acceptance as the preferred index of CT dose in children. However it was developed based on non-clinical data. To compare the accuracy of size-specific dose estimate (SSDE) based on geometric and body weight measures in pediatric chest and abdomen CT scans, versus the more accurate [Formula: see text] (mean SSDE based on water-equivalent diameter). We retrospectively identified 50 consecutive children (age CT examination and 50 children who underwent abdomen CT. We measured anteroposterior diameter (DAP) and lateral diameter (DLAT) at the central slice (of scan length) of each patient and calculated DAP+LAT (anteroposterior diameter plus lateral diameter) and DED (effective diameter) for each patient. We calculated the following in each child: (1) SSDEs based on DAP, DLAT, DAP+LAT, DED, and body weight, and (2) SSDE based on software calculation of mean water-equivalent diameter ([Formula: see text] adopted standard within our study). We used intraclass correlation coefficient (ICC) and Bland-Altman analysis to compare agreement between the SSDEs and [Formula: see text]. Gender and age distribution were similar between chest and abdomen CT groups; mean body weight was 37 kg for both groups, with ranges of 6-130 kg (chest) and 8-107 kg (abdomen). SSDEs had very strong agreement (ICC>0.9) with [Formula: see text]. SSDEs based on DLAT had 95% limits of agreement of up to 43% with [Formula: see text]. SSDEs based on other parameters (body weight, DAP, DAP+LAT, DED) had 95% limits of agreement of up to 25%. Differences between SSDEs calculated using various indications of patient size (geometric indices and patient weight) and the more accurate [Formula: see text] calculated using proprietary software were generally small, with the possible exception for lateral diameter, and provide acceptable dose estimates for body CT in children.

  4. Meta-analysis for evidence synthesis in plant pathology: an overview.

    Science.gov (United States)

    Madden, L V; Paul, P A

    2011-01-01

    Meta-analysis is the analysis of the results of multiple studies, which is typically performed in order to synthesize evidence from many possible sources in a formal probabilistic manner. In a simple sense, the outcome of each study becomes a single observation in the meta-analysis of all available studies. The methodology was developed originally in the social sciences by Smith, Glass, Rosenthal, Hunter, and Schmidt, based on earlier pioneering contributions in statistics by Fisher, Pearson, Yates, and Cochran, but this approach to research synthesis has now been embraced within many scientific disciplines. However, only a handful of articles have been published in plant pathology and related fields utilizing meta-analysis. After reviewing basic concepts and approaches, methods for estimating parameters and interpreting results are shown. The advantages of meta-analysis are presented in terms of prediction and risk analysis, and the high statistical power that can be achieved for detecting significant effects of treatments or significant relationships between variables. Based on power considerations, the fallacy of naïve counting of P values in a narrative review is demonstrated. Although there are many advantages to meta-analysis, results can be biased if the analysis is based on a nonrepresentative sample of study outcomes. Therefore, novel approaches for characterizing the upper bound on the bias are discussed, in order to show the robustness of meta-analysis to possible violation of assumptions.

  5. Using nearest neighbors for accurate estimation of ultrasonic attenuation in the spectral domain.

    Science.gov (United States)

    Hasan, Md Kamrul; Hussain, Mohammad Arafat; Ara, Sharmin R; Lee, Soo Yeol; Alam, S Kaisar

    2013-06-01

    Attenuation is a key diagnostic parameter of tissue pathology change and thus may play a vital role in the quantitative discrimination of malignant and benign tumors in soft tissue. In this paper, two novel techniques are proposed for estimating the average ultrasonic attenuation in soft tissue using the spectral domain weighted nearest neighbor method. Because the attenuation coefficient of soft tissues can be considered to be a continuous function in a small neighborhood, we directly estimate an average value of it from the slope of the regression line fitted to the 1) modified average midband fit value and 2) the average center frequency shift along the depth. To calculate the average midband fit value, an average regression line computed from the exponentially weighted short-time Fourier transform (STFT) of the neighboring 1-D signal blocks, in the axial and lateral directions, is fitted over the usable bandwidth of the normalized power spectrum. The average center frequency downshift is computed from the maximization of a cost function defined from the normalized spectral cross-correlation (NSCC) of exponentially weighted nearest neighbors in both directions. Different from the large spatial signal-block-based spectral stability approach, a costfunction- based approach incorporating NSCC functions of neighboring 1-D signal blocks is introduced. This paves the way for using comparatively smaller spatial area along the lateral direction, a necessity for producing more realistic attenuation estimates for heterogeneous tissue. For accurate estimation of the attenuation coefficient, we also adopt a reference-phantombased diffraction-correction technique for both methods. The proposed attenuation estimation algorithm demonstrates better performance than other reported techniques in the tissue-mimicking phantom and the in vivo breast data analysis.

  6. Size matters: how accurate is clinical estimation of traumatic wound size?

    Science.gov (United States)

    Peterson, N; Stevenson, H; Sahni, V

    2014-01-01

    The presentation of traumatic wounds is commonplace in the accident & emergency department. Often, these wounds need referral to specialist care, e.g. trauma & orthopaedic, plastic or maxillofacial surgeons. Documentation and communication of the size of the wound can influence management, e.g. Gustilo & Anderson classification of open fractures. Several papers acknowledge the variability in measurement of chronic wounds, but there is no data regarding accuracy of traumatic wound assessment. The authors hypothesised that the estimation of wound size and subsequent communication or documentation was often inaccurate, with high inter-observer variability. A study was designed to assess this hypothesis. A total of 7 scaled images of wounds related to trauma were obtained from an Internet search engine. The questionnaire asked 3 questions regarding mechanism of injury, relevant anatomy and proposed treatment, to simulate real patient assessment. One further question addressed the estimation of wound size. 50 doctors of varying experience across several specialities were surveyed. The images were analysed after data collection had finished to provide appropriate measurements, and compared to the questionnaire results by a researcher blinded to the demographics of the individual. Our results show that there is a high inter-observer variability and inaccuracy in the estimation of wound size. This inaccuracy was directional and affected by gender. Male doctors were more likely to overestimate the size of wounds, whilst their female colleagues were more likely to underestimate size. The estimation of wound size is a common requirement of clinical practice, and inaccurate interpretation of size may influence surgical management. Assessment using estimation was inaccurate, with high inter-observer variability. Assessment of traumatic wounds that require surgical management should be accurately measured, possibly using photography and ruler measurement. Copyright © 2012

  7. Accurate estimation of motion blur parameters in noisy remote sensing image

    Science.gov (United States)

    Shi, Xueyan; Wang, Lin; Shao, Xiaopeng; Wang, Huilin; Tao, Zhong

    2015-05-01

    The relative motion between remote sensing satellite sensor and objects is one of the most common reasons for remote sensing image degradation. It seriously weakens image data interpretation and information extraction. In practice, point spread function (PSF) should be estimated firstly for image restoration. Identifying motion blur direction and length accurately is very crucial for PSF and restoring image with precision. In general, the regular light-and-dark stripes in the spectrum can be employed to obtain the parameters by using Radon transform. However, serious noise existing in actual remote sensing images often causes the stripes unobvious. The parameters would be difficult to calculate and the error of the result relatively big. In this paper, an improved motion blur parameter identification method to noisy remote sensing image is proposed to solve this problem. The spectrum characteristic of noisy remote sensing image is analyzed firstly. An interactive image segmentation method based on graph theory called GrabCut is adopted to effectively extract the edge of the light center in the spectrum. Motion blur direction is estimated by applying Radon transform on the segmentation result. In order to reduce random error, a method based on whole column statistics is used during calculating blur length. Finally, Lucy-Richardson algorithm is applied to restore the remote sensing images of the moon after estimating blur parameters. The experimental results verify the effectiveness and robustness of our algorithm.

  8. Accurate estimation of the myocardium global function from reduced magnetic resonance image acquisitions.

    Science.gov (United States)

    El-Rewaidy, Hossam; Khalifa, Ayman; Fahmy, Ahmed S

    2014-01-01

    Evaluating the heart global function from magnetic resonance images is based on estimating a number of functional parameters such as the left ventricular (LV) volume, LV mass, ejection fraction, and stroke volume. Estimating these parameters requires accurate calculation of the volumes enclosed by the inner and outer surfaces of the LV chamber at the max contraction and relaxation states of the heart. Currently, this is achieved through acquisition and segmentation of a large number of short-axis (SAX) views of the LV, which is time-consuming and expensive. Reducing the number of acquisitions results in undersampling the LV surfaces and hence increases the calculation errors. In this work, we describe and evaluate a method for estimating the cardiac parameters from a small number of image acquisitions that includes one long-axis (LAX) view of the LV. In this method, the LAX contour is used to swipe the SAX contours to fill in the missed LV surface between the SAX slices. Results on 25 patients and CT phantoms shows that, given the same number of slices, the proposed method is superior to other methods.

  9. Accurate estimation of the RMS emittance from single current amplifier data

    International Nuclear Information System (INIS)

    Stockli, Martin P.; Welton, R.F.; Keller, R.; Letchford, A.P.; Thomae, R.W.; Thomason, J.W.G.

    2002-01-01

    This paper presents the SCUBEEx rms emittance analysis, a self-consistent, unbiased elliptical exclusion method, which combines traditional data-reduction methods with statistical methods to obtain accurate estimates for the rms emittance. Rather than considering individual data, the method tracks the average current density outside a well-selected, variable boundary to separate the measured beam halo from the background. The average outside current density is assumed to be part of a uniform background and not part of the particle beam. Therefore the average outside current is subtracted from the data before evaluating the rms emittance within the boundary. As the boundary area is increased, the average outside current and the inside rms emittance form plateaus when all data containing part of the particle beam are inside the boundary. These plateaus mark the smallest acceptable exclusion boundary and provide unbiased estimates for the average background and the rms emittance. Small, trendless variations within the plateaus allow for determining the uncertainties of the estimates caused by variations of the measured background outside the smallest acceptable exclusion boundary. The robustness of the method is established with complementary variations of the exclusion boundary. This paper presents a detailed comparison between traditional data reduction methods and SCUBEEx by analyzing two complementary sets of emittance data obtained with a Lawrence Berkeley National Laboratory and an ISIS H - ion source

  10. Characterization of a signal recording system for accurate velocity estimation using a VISAR

    Science.gov (United States)

    Rav, Amit; Joshi, K. D.; Singh, Kulbhushan; Kaushik, T. C.

    2018-02-01

    The linearity of a signal recording system (SRS) in time as well as in amplitude are important for the accurate estimation of the free surface velocity history of a moving target during shock loading and unloading when measured using optical interferometers such as a velocity interferometer system for any reflector (VISAR). Signal recording being the first step in a long sequence of signal processes, the incorporation of errors due to nonlinearity, and low signal-to-noise ratio (SNR) affects the overall accuracy and precision of the estimation of velocity history. In shock experiments the small duration (a few µs) of loading/unloading, the reflectivity of moving target surface, and the properties of optical components, control the amount of input of light to the SRS of a VISAR and this in turn affects the linearity and SNR of the overall measurement. These factors make it essential to develop in situ procedures for (i) minimizing the effect of signal induced noise and (ii) determine the linear region of operation for the SRS. Here we report on a procedure for the optimization of SRS parameters such as photodetector gain, optical power, aperture etc, so as to achieve a linear region of operation with a high SNR. The linear region of operation so determined has been utilized successfully to estimate the temporal history of the free surface velocity of the moving target in shock experiments.

  11. Using Beta Coefficients to Impute Missing Correlations in Meta-Analysis Research: Reasons for Caution.

    Science.gov (United States)

    Roth, Philip L; Le, Huy; Oh, In-Sue; Van Iddekinge, Chad H; Bobko, Philip

    2018-01-25

    Meta-analysis has become a well-accepted method for synthesizing empirical research about a given phenomenon. Many meta-analyses focus on synthesizing correlations across primary studies, but some primary studies do not report correlations. Peterson and Brown (2005) suggested that researchers could use standardized regression weights (i.e., beta coefficients) to impute missing correlations. Indeed, their beta estimation procedures (BEPs) have been used in meta-analyses in a wide variety of fields. In this study, the authors evaluated the accuracy of BEPs in meta-analysis. We first examined how use of BEPs might affect results from a published meta-analysis. We then developed a series of Monte Carlo simulations that systematically compared the use of existing correlations (that were not missing) to data sets that incorporated BEPs (that impute missing correlations from corresponding beta coefficients). These simulations estimated ρ̄ (mean population correlation) and SDρ (true standard deviation) across a variety of meta-analytic conditions. Results from both the existing meta-analysis and the Monte Carlo simulations revealed that BEPs were associated with potentially large biases when estimating ρ̄ and even larger biases when estimating SDρ. Using only existing correlations often substantially outperformed use of BEPs and virtually never performed worse than BEPs. Overall, the authors urge a return to the standard practice of using only existing correlations in meta-analysis. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  12. A Simple yet Accurate Method for the Estimation of the Biovolume of Planktonic Microorganisms.

    Science.gov (United States)

    Saccà, Alessandro

    2016-01-01

    Determining the biomass of microbial plankton is central to the study of fluxes of energy and materials in aquatic ecosystems. This is typically accomplished by applying proper volume-to-carbon conversion factors to group-specific abundances and biovolumes. A critical step in this approach is the accurate estimation of biovolume from two-dimensional (2D) data such as those available through conventional microscopy techniques or flow-through imaging systems. This paper describes a simple yet accurate method for the assessment of the biovolume of planktonic microorganisms, which works with any image analysis system allowing for the measurement of linear distances and the estimation of the cross sectional area of an object from a 2D digital image. The proposed method is based on Archimedes' principle about the relationship between the volume of a sphere and that of a cylinder in which the sphere is inscribed, plus a coefficient of 'unellipticity' introduced here. Validation and careful evaluation of the method are provided using a variety of approaches. The new method proved to be highly precise with all convex shapes characterised by approximate rotational symmetry, and combining it with an existing method specific for highly concave or branched shapes allows covering the great majority of cases with good reliability. Thanks to its accuracy, consistency, and low resources demand, the new method can conveniently be used in substitution of any extant method designed for convex shapes, and can readily be coupled with automated cell imaging technologies, including state-of-the-art flow-through imaging devices.

  13. A Simple yet Accurate Method for the Estimation of the Biovolume of Planktonic Microorganisms.

    Directory of Open Access Journals (Sweden)

    Alessandro Saccà

    Full Text Available Determining the biomass of microbial plankton is central to the study of fluxes of energy and materials in aquatic ecosystems. This is typically accomplished by applying proper volume-to-carbon conversion factors to group-specific abundances and biovolumes. A critical step in this approach is the accurate estimation of biovolume from two-dimensional (2D data such as those available through conventional microscopy techniques or flow-through imaging systems. This paper describes a simple yet accurate method for the assessment of the biovolume of planktonic microorganisms, which works with any image analysis system allowing for the measurement of linear distances and the estimation of the cross sectional area of an object from a 2D digital image. The proposed method is based on Archimedes' principle about the relationship between the volume of a sphere and that of a cylinder in which the sphere is inscribed, plus a coefficient of 'unellipticity' introduced here. Validation and careful evaluation of the method are provided using a variety of approaches. The new method proved to be highly precise with all convex shapes characterised by approximate rotational symmetry, and combining it with an existing method specific for highly concave or branched shapes allows covering the great majority of cases with good reliability. Thanks to its accuracy, consistency, and low resources demand, the new method can conveniently be used in substitution of any extant method designed for convex shapes, and can readily be coupled with automated cell imaging technologies, including state-of-the-art flow-through imaging devices.

  14. Accurate and fast methods to estimate the population mutation rate from error prone sequences

    Directory of Open Access Journals (Sweden)

    Miyamoto Michael M

    2009-08-01

    Full Text Available Abstract Background The population mutation rate (θ remains one of the most fundamental parameters in genetics, ecology, and evolutionary biology. However, its accurate estimation can be seriously compromised when working with error prone data such as expressed sequence tags, low coverage draft sequences, and other such unfinished products. This study is premised on the simple idea that a random sequence error due to a chance accident during data collection or recording will be distributed within a population dataset as a singleton (i.e., as a polymorphic site where one sampled sequence exhibits a unique base relative to the common nucleotide of the others. Thus, one can avoid these random errors by ignoring the singletons within a dataset. Results This strategy is implemented under an infinite sites model that focuses on only the internal branches of the sample genealogy where a shared polymorphism can arise (i.e., a variable site where each alternative base is represented by at least two sequences. This approach is first used to derive independently the same new Watterson and Tajima estimators of θ, as recently reported by Achaz 1 for error prone sequences. It is then used to modify the recent, full, maximum-likelihood model of Knudsen and Miyamoto 2, which incorporates various factors for experimental error and design with those for coalescence and mutation. These new methods are all accurate and fast according to evolutionary simulations and analyses of a real complex population dataset for the California seahare. Conclusion In light of these results, we recommend the use of these three new methods for the determination of θ from error prone sequences. In particular, we advocate the new maximum likelihood model as a starting point for the further development of more complex coalescent/mutation models that also account for experimental error and design.

  15. Does bioelectrical impedance analysis accurately estimate the condition of threatened and endangered desert fish species?

    Science.gov (United States)

    Dibble, Kimberly L.; Yard, Micheal D.; Ward, David L.; Yackulic, Charles B.

    2017-01-01

    Bioelectrical impedance analysis (BIA) is a nonlethal tool with which to estimate the physiological condition of animals that has potential value in research on endangered species. However, the effectiveness of BIA varies by species, the methodology continues to be refined, and incidental mortality rates are unknown. Under laboratory conditions we tested the value of using BIA in addition to morphological measurements such as total length and wet mass to estimate proximate composition (lipid, protein, ash, water, dry mass, energy density) in the endangered Humpback Chub Gila cypha and Bonytail G. elegans and the species of concern Roundtail Chub G. robusta and conducted separate trials to estimate the mortality rates of these sensitive species. Although Humpback and Roundtail Chub exhibited no or low mortality in response to taking BIA measurements versus handling for length and wet-mass measurements, Bonytails exhibited 14% and 47% mortality in the BIA and handling experiments, respectively, indicating that survival following stress is species specific. Derived BIA measurements were included in the best models for most proximate components; however, the added value of BIA as a predictor was marginal except in the absence of accurate wet-mass data. Bioelectrical impedance analysis improved the R2 of the best percentage-based models by no more than 4% relative to models based on morphology. Simulated field conditions indicated that BIA models became increasingly better than morphometric models at estimating proximate composition as the observation error around wet-mass measurements increased. However, since the overall proportion of variance explained by percentage-based models was low and BIA was mostly a redundant predictor, we caution against the use of BIA in field applications for these sensitive fish species.

  16. Spot urine sodium measurements do not accurately estimate dietary sodium intake in chronic kidney disease12

    Science.gov (United States)

    Dougher, Carly E; Rifkin, Dena E; Anderson, Cheryl AM; Smits, Gerard; Persky, Martha S; Block, Geoffrey A; Ix, Joachim H

    2016-01-01

    Background: Sodium intake influences blood pressure and proteinuria, yet the impact on long-term outcomes is uncertain in chronic kidney disease (CKD). Accurate assessment is essential for clinical and public policy recommendations, but few large-scale studies use 24-h urine collections. Recent studies that used spot urine sodium and associated estimating equations suggest that they may provide a suitable alternative, but their accuracy in patients with CKD is unknown. Objective: We compared the accuracy of 4 equations [the Nerbass, INTERSALT (International Cooperative Study on Salt, Other Factors, and Blood Pressure), Tanaka, and Kawasaki equations] that use spot urine sodium to estimate 24-h sodium excretion in patients with moderate to advanced CKD. Design: We evaluated the accuracy of spot urine sodium to predict mean 24-h urine sodium excretion over 9 mo in 129 participants with stage 3–4 CKD. Spot morning urine sodium was used in 4 estimating equations. Bias, precision, and accuracy were assessed and compared across each equation. Results: The mean age of the participants was 67 y, 52% were female, and the mean estimated glomerular filtration rate was 31 ± 9 mL · min–1 · 1.73 m–2. The mean ± SD number of 24-h urine collections was 3.5 ± 0.8/participant, and the mean 24-h sodium excretion was 168.2 ± 67.5 mmol/d. Although the Tanaka equation demonstrated the least bias (mean: −8.2 mmol/d), all 4 equations had poor precision and accuracy. The INTERSALT equation demonstrated the highest accuracy but derived an estimate only within 30% of mean measured sodium excretion in only 57% of observations. Bland-Altman plots revealed systematic bias with the Nerbass, INTERSALT, and Tanaka equations, underestimating sodium excretion when intake was high. Conclusion: These findings do not support the use of spot urine specimens to estimate dietary sodium intake in patients with CKD and research studies enriched with patients with CKD. The parent data for this

  17. Fast and Accurate Video PQoS Estimation over Wireless Networks

    Directory of Open Access Journals (Sweden)

    Emanuele Viterbo

    2008-06-01

    Full Text Available This paper proposes a curve fitting technique for fast and accurate estimation of the perceived quality of streaming media contents, delivered within a wireless network. The model accounts for the effects of various network parameters such as congestion, radio link power, and video transmission bit rate. The evaluation of the perceived quality of service (PQoS is based on the well-known VQM objective metric, a powerful technique which is highly correlated to the more expensive and time consuming subjective metrics. Currently, PQoS is used only for offline analysis after delivery of the entire video content. Thanks to the proposed simple model, we can estimate in real time the video PQoS and we can rapidly adapt the content transmission through scalable video coding and bit rates in order to offer the best perceived quality to the end users. The designed model has been validated through many different measurements in realistic wireless environments using an ad hoc WiFi test bed.

  18. Robust and Accurate Multiple-Camera Pose Estimation toward Robotic Applications

    Directory of Open Access Journals (Sweden)

    Yong Liu

    2014-09-01

    Full Text Available Pose estimation methods in robotics applications frequently suffer from inaccuracy due to a lack of correspondence and real-time constraints, and instability from a wide range of viewpoints, etc. In this paper, we present a novel approach for estimating the poses of all the cameras in a multi-camera system in which each camera is placed rigidly using only a few coplanar points simultaneously. Instead of solving the orientation and translation for the multi-camera system from the overlapping point correspondences among all the cameras directly, we employ homography, which can map image points with 3D coplanar-referenced points. In our method, we first establish the corresponding relations between each camera by their Euclidean geometries and optimize the homographies of the cameras; then, we solve the orientation and translation for the optimal homographies. The results from simulations and real case experiments show that our approach is accurate and robust for implementation in robotics applications. Finally, a practical implementation in a ping-pong robot is described in order to confirm the validity of our approach.

  19. Can student health professionals accurately estimate alcohol content in commonly occurring drinks?

    Science.gov (United States)

    Sinclair, Julia; Searle, Emma

    2016-08-01

    Correct identification of alcohol as a contributor to, or comorbidity of, many psychiatric diseases requires health professionals to be competent and confident to take an accurate alcohol history. Being able to estimate (or calculate) the alcohol content in commonly consumed drinks is a prerequisite for quantifying levels of alcohol consumption. The aim of this study was to assess this ability in medical and nursing students. A cross-sectional survey of 891 medical and nursing students across different years of training was conducted. Students were asked the alcohol content of 10 different alcoholic drinks by seeing a slide of the drink (with picture, volume and percentage of alcohol by volume) for 30 s. Overall, the mean number of correctly estimated drinks (out of the 10 tested) was 2.4, increasing to just over 3 if a 10% margin of error was used. Wine and premium strength beers were underestimated by over 50% of students. Those who drank alcohol themselves, or who were further on in their clinical training, did better on the task, but overall the levels remained low. Knowledge of, or the ability to work out, the alcohol content of commonly consumed drinks is poor, and further research is needed to understand the reasons for this and the impact this may have on the likelihood to undertake screening or initiate treatment.

  20. Can student health professionals accurately estimate alcohol content in commonly occurring drinks?

    Science.gov (United States)

    Sinclair, Julia; Searle, Emma

    2016-01-01

    Objectives: Correct identification of alcohol as a contributor to, or comorbidity of, many psychiatric diseases requires health professionals to be competent and confident to take an accurate alcohol history. Being able to estimate (or calculate) the alcohol content in commonly consumed drinks is a prerequisite for quantifying levels of alcohol consumption. The aim of this study was to assess this ability in medical and nursing students. Methods: A cross-sectional survey of 891 medical and nursing students across different years of training was conducted. Students were asked the alcohol content of 10 different alcoholic drinks by seeing a slide of the drink (with picture, volume and percentage of alcohol by volume) for 30 s. Results: Overall, the mean number of correctly estimated drinks (out of the 10 tested) was 2.4, increasing to just over 3 if a 10% margin of error was used. Wine and premium strength beers were underestimated by over 50% of students. Those who drank alcohol themselves, or who were further on in their clinical training, did better on the task, but overall the levels remained low. Conclusions: Knowledge of, or the ability to work out, the alcohol content of commonly consumed drinks is poor, and further research is needed to understand the reasons for this and the impact this may have on the likelihood to undertake screening or initiate treatment. PMID:27536344

  1. Single-cell entropy for accurate estimation of differentiation potency from a cell's transcriptome

    Science.gov (United States)

    Teschendorff, Andrew E.; Enver, Tariq

    2017-06-01

    The ability to quantify differentiation potential of single cells is a task of critical importance. Here we demonstrate, using over 7,000 single-cell RNA-Seq profiles, that differentiation potency of a single cell can be approximated by computing the signalling promiscuity, or entropy, of a cell's transcriptome in the context of an interaction network, without the need for feature selection. We show that signalling entropy provides a more accurate and robust potency estimate than other entropy-based measures, driven in part by a subtle positive correlation between the transcriptome and connectome. Signalling entropy identifies known cell subpopulations of varying potency and drug resistant cancer stem-cell phenotypes, including those derived from circulating tumour cells. It further reveals that expression heterogeneity within single-cell populations is regulated. In summary, signalling entropy allows in silico estimation of the differentiation potency and plasticity of single cells and bulk samples, providing a means to identify normal and cancer stem-cell phenotypes.

  2. 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…

  3. 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...

  4. 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.

  5. 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...

  6. 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

  7. Modeling Site Heterogeneity with Posterior Mean Site Frequency Profiles Accelerates Accurate Phylogenomic Estimation.

    Science.gov (United States)

    Wang, Huai-Chun; Minh, Bui Quang; Susko, Edward; Roger, Andrew J

    2018-03-01

    Proteins have distinct structural and functional constraints at different sites that lead to site-specific preferences for particular amino acid residues as the sequences evolve. Heterogeneity in the amino acid substitution process between sites is not modeled by commonly used empirical amino acid exchange matrices. Such model misspecification can lead to artefacts in phylogenetic estimation such as long-branch attraction. Although sophisticated site-heterogeneous mixture models have been developed to address this problem in both Bayesian and maximum likelihood (ML) frameworks, their formidable computational time and memory usage severely limits their use in large phylogenomic analyses. Here we propose a posterior mean site frequency (PMSF) method as a rapid and efficient approximation to full empirical profile mixture models for ML analysis. The PMSF approach assigns a conditional mean amino acid frequency profile to each site calculated based on a mixture model fitted to the data using a preliminary guide tree. These PMSF profiles can then be used for in-depth tree-searching in place of the full mixture model. Compared with widely used empirical mixture models with $k$ classes, our implementation of PMSF in IQ-TREE (http://www.iqtree.org) speeds up the computation by approximately $k$/1.5-fold and requires a small fraction of the RAM. Furthermore, this speedup allows, for the first time, full nonparametric bootstrap analyses to be conducted under complex site-heterogeneous models on large concatenated data matrices. Our simulations and empirical data analyses demonstrate that PMSF can effectively ameliorate long-branch attraction artefacts. In some empirical and simulation settings PMSF provided more accurate estimates of phylogenies than the mixture models from which they derive.

  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. 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.

  10. Research Protocol for Systematic Review and Meta-Analysis of Elder Abuse Prevalence Studies.

    Science.gov (United States)

    Yon, Yongjie; Mikton, Christopher; Gassoumis, Zachary D; Wilber, Kathleen H

    2017-06-01

    Elder abuse is an important public health and human rights issue, yet its true extent is not well understood. To address this, we will conduct a systematic review and meta-analysis of elder abuse prevalence studies from around the world. This protocol describes the methodological approach to be adopted for conducting this systematic review and meta-analysis. In particular, the protocol describes the search strategies and eligibility criteria to be used to identify and select studies and how data from the selected studies will be extracted for analysis. The protocol also describes the analytical approach that will be used to calculate pooled prevalence estimates and discusses the use of meta-regression to assess how studies' characteristics influence the prevalence estimates. This protocol conforms to the Preferred Reporting Items for Systematic reviews and Meta-Analysis - or PRISMA - guidelines and has been registered with the PROSPERO International Prospective Register of systematic reviews.

  11. 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…

  12. 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.

  13. Review of applications of Bayesian meta-analysis in systematic reviews

    Directory of Open Access Journals (Sweden)

    Melissa Glenda Lewis

    2015-01-01

    Full Text Available Background: Systematic reviews are important sources of evidence in health care research. These reviews may or may not include meta-analysis as a statistical assimilation of the results of several studies in order to acquire a pooled estimate. Systematic review with meta-analysis is considered as a robust method of evidence synthesis. The methodology concerned with traditional meta-analysis does not incorporate external prior information. Hence, Bayesian methods are essential due to the natural process of incorporating the past information and updating the belief. Bayesian methods to meta-analysis have been developed with a motivation from the limitations of traditional meta-analysis such as dealing with missing data, problem with limited number of studies and problem with sparse event data in both the groups. The present article aims to unearth as to what extent Bayesian methods have been used in systematic reviews, evolution and its applications. This article also highlights the existing challenges and opportunities. Methods: The literature search was performed in databases such as Cochrane, PubMed, ProQuest and Scopus using the keywords “Bayesian Meta-analysis” and “Bayesian Meta-analyses”. All the methodology and application oriented papers specific to Bayesian meta-analysis were considered relevant for this review. Conclusion: Bayesian meta-analysis has gained popularity in the field of evidence synthesis of clinical trials. However, it did not pick up momentum in summarizing public health interventions, owing to the fact that public health interventions are targeted to highly heterogeneous population, multi-component interventions, and multiple outcomes and influenced by the context

  14. Transthoracic echocardiography: an accurate and precise method for estimating cardiac output in the critically ill patient.

    Science.gov (United States)

    Mercado, Pablo; Maizel, Julien; Beyls, Christophe; Titeca-Beauport, Dimitri; Joris, Magalie; Kontar, Loay; Riviere, Antoine; Bonef, Olivier; Soupison, Thierry; Tribouilloy, Christophe; de Cagny, Bertrand; Slama, Michel

    2017-06-09

    % yielded a sensitivity of 88% and specificity of 66% for detecting a ΔCO-PAC of more than 10%. In critically ill mechanically ventilated patients, CO-TTE is an accurate and precise method for estimating CO. Furthermore, CO-TTE can accurately track variations in CO.

  15. Prognostic Value of microRNA-224 in Various Cancers: A Meta-analysis.

    Science.gov (United States)

    Zhang, Yue; Guo, Cong-Cong; Guan, Dong-Hui; Yang, Chuan-Hua; Jiang, Yue-Hua

    2017-07-01

    During previous studies, microRNA-224 (miR-224) was frequently investigated and discovered to be of vital significance to prognosis of patients with various cancers. However, its accurate prognostic value has not been estimated worldwide. Herein, we performed meta-analysis to assess its potential predictive value in a variety of human tumors. Qualified researches were identified up to March 1, 2017 through performing online searches in PubMed, EMBASE, Web of Science and Cochrane Database of Systematic Reviews. Overall survival (OS), disease-free survival (DFS) or progression-free survival (PFS) as a prognosis for various cancers were extracted and calculated, if available. Pooled hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Stata version 13.0 (StataCorp, College Station, Texas, USA). 22 eligible studies with 3000 patients were ultimately brought into the current meta-analysis. It suggested that high miR-224 expression was significantly associated with poor OS in tissue (HR = 1.43, 95% CI = 1.00-2.03). During multivariate analysis, high miR-224 expression was more significantly associated with OS in tissue (HR = 2.81, 95% CI = 1.91-4.13). Likewise, there were significant associations between tissue miR-224 expression and colorectal cancer (CRC), diffuse large B-cell lymphoma (DLBCL) and gastric cancer (GC) patients (p present researches are concerned, tissue miR-224 has a significantly prognostic value in various cancers, especially in CRC, DLBCL and GC. Due to the complicated pathogenesis of cancers, more large-scale and standard researches are requisite. Copyright © 2017 IMSS. Published by Elsevier Inc. All rights reserved.

  16. Environmental ambient temperature and blood pressure in adults: A systematic review and meta-analysis.

    Science.gov (United States)

    Wang, Qiong; Li, Changchang; Guo, Yanfang; Barnett, Adrian G; Tong, Shilu; Phung, Dung; Chu, Cordia; Dear, Keith; Wang, Xuemei; Huang, Cunrui

    2017-01-01

    Although many individual studies have examined the association between temperature and blood pressure (BP), they used different methods and also their results were somewhat inconsistent. The aims of this study are to quantitatively summarize previous studies and to systematically assess the methodological issues to make recommendations for future research. We searched relevant empirical studies published before January 2016 concerning temperature and BP among adults using the MEDLINE, Embase and PubMed databases. Mean changes in systolic (SBP) and diastolic blood pressure (DBP) per 1°C reduction in temperature were pooled using a random-effects meta-analysis. Of 23 studies included, 14 were used for meta-analysis. Consistent, statistically significant, inverse associations were observed between ambient temperature (mean, maximum, minimum outdoor temperature and indoor temperature) and BP. An 1°C decrease in mean daily outdoor temperature was associated with an increase in SBP and DBP of 0.26mmHg (95% CI: 0.18-0.33) and 0.13 (95% CI: 0.11-0.16), respectively. The increase was greater in people with conditions related to cardiovascular disease. An 1°C decrease in indoor temperature was associated with 0.38mmHg (0.18-0.58) increase in SBP, while the effects on DBP were not estimated due to limited studies. Among the previous studies on temperature-BP relationship, temperature and BP measurements are not accurate enough and statistical methods need to be improved. Lower ambient temperatures seem to increase adults' BP and people with conditions related to cardiovascular disease are more susceptible to drops in temperature. Indoor temperature appeared to have a stronger effect on BP than outdoor temperature. To understand temperature-BP relationship well, a study combining repeated personal temperature exposure and ambulatory BP monitoring, applying improved statistical methods to examine potential non-linear relationship is warranted. Copyright © 2016 Elsevier B

  17. 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

  18. 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

  19. 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

  20. Social cognition in Huntington's disease: A meta-analysis.

    Science.gov (United States)

    Bora, Emre; Velakoulis, Dennis; Walterfang, Mark

    2016-01-15

    Neurocognitive impairment in Huntington's disease (HD) frequently includes deficits in emotion recognition, and recent studies have also provided evidence for deficits in theory of mind (ToM). There have been conflicting reports regarding the extent of emotion recognition and ToM deficits before the onset of motor symptoms in HD. In this meta-analysis, ToM and emotion recognition performances of 2226HD or pre-manifest HD and 998 healthy controls were included in the meta-analysis. Meta-regression analyses were conducted to investigate the relationship between social cognition deficits and demographic, cognitive and clinical features in HD. HD patients were significantly less accurate than controls in ToM and across all emotions in response to both facial and vocal stimuli. ToM (d=1.72) and recognition of negative emotions (d=1.20-1.33), especially anger, disgust and fear (d=1.26-1.52) were severely impaired. Pre-manifest HD was also associated with impairment in social cognition. The severity of emotion recognition impairment was significantly associated with disease burden, proximity of onset of motor symptoms and cognitive impairment. Social cognition impairments are potential biomarkers of disease onset and progression in HD. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Gene regulatory network reconstruction using Bayesian networks, the Dantzig Selector, the Lasso and their meta-analysis.

    Directory of Open Access Journals (Sweden)

    Matthieu Vignes

    Full Text Available Modern technologies and especially next generation sequencing facilities are giving a cheaper access to genotype and genomic data measured on the same sample at once. This creates an ideal situation for multifactorial experiments designed to infer gene regulatory networks. The fifth "Dialogue for Reverse Engineering Assessments and Methods" (DREAM5 challenges are aimed at assessing methods and associated algorithms devoted to the inference of biological networks. Challenge 3 on "Systems Genetics" proposed to infer causal gene regulatory networks from different genetical genomics data sets. We investigated a wide panel of methods ranging from Bayesian networks to penalised linear regressions to analyse such data, and proposed a simple yet very powerful meta-analysis, which combines these inference methods. We present results of the Challenge as well as more in-depth analysis of predicted networks in terms of structure and reliability. The developed meta-analysis was ranked first among the 16 teams participating in Challenge 3A. It paves the way for future extensions of our inference method and more accurate gene network estimates in the context of genetical genomics.

  2. Scientists Admitting to Plagiarism: A Meta-analysis of Surveys.

    Science.gov (United States)

    Pupovac, Vanja; Fanelli, Daniele

    2015-10-01

    We conducted a systematic review and meta-analysis of anonymous surveys asking scientists whether they ever committed various forms of plagiarism. From May to December 2011 we searched 35 bibliographic databases, five grey literature databases and hand searched nine journals for potentially relevant studies. We included surveys that asked scientists if, in a given recall period, they had committed or knew of a colleague who committed plagiarism, and from each survey extracted the proportion of those who reported at least one case. Studies that focused on academic (i.e. student) plagiarism were excluded. Literature searches returned 12,460 titles from which 17 relevant survey studies were identified. Meta-analysis of studies reporting committed (N = 7) and witnessed (N = 11) plagiarism yielded a pooled estimate of, respectively, 1.7% (95% CI 1.2-2.4) and 30% (95% CI 17-46). Basic methodological factors, including sample size, year of survey, delivery method and whether survey questions were explicit rather than indirect made a significant difference on survey results. Even after controlling for these methodological factors, between-study differences in admission rates were significantly above those expected by sampling error alone and remained largely unexplained. Despite several limitations of the data and of this meta-analysis, we draw three robust conclusions: (1) The rate at which scientists report knowing a colleague who committed plagiarism is higher than for data fabrication and falsification; (2) The rate at which scientists report knowing a colleague who committed plagiarism is correlated to that of fabrication and falsification; (3) The rate at which scientists admit having committed either form of misconduct (i.e. fabrication, falsification and plagiarism) in surveys has declined over time.

  3. Validity of the alcohol purchase task: a meta-analysis.

    Science.gov (United States)

    Kiselica, Andrew M; Webber, Troy A; Bornovalova, Marina A

    2016-05-01

    Behavioral economists assess alcohol consumption as a function of unit price. This method allows construction of demand curves and demand indices, which are thought to provide precise numerical estimates of risk for alcohol problems. One of the more commonly used behavioral economic measures is the Alcohol Purchase Task (APT). Although the APT has shown promise as a measure of risk for alcohol problems, the construct validity and incremental utility of the APT remain unclear. This paper presents a meta-analysis of the APT literature. Sixteen studies were included in the meta-analysis. Studies were gathered via searches of the PsycInfo, PubMed, Web of Science and EconLit research databases. Random-effects meta-analyses with inverse variance weighting were used to calculate summary effect sizes for each demand index-drinking outcome relationship. Moderation of these effects by drinking status (regular versus heavy drinkers) was examined. Additionally, tests of the incremental utility of the APT indices in predicting drinking problems above and beyond measuring alcohol consumption were performed. The APT indices were correlated in the expected directions with drinking outcomes, although many effects were small in size. These effects were typically not moderated by the drinking status of the samples. Additionally, the intensity metric demonstrated incremental utility in predicting alcohol use disorder symptoms beyond measuring drinking. The Alcohol Purchase Task appears to have good construct validity, but limited incremental utility in estimating risk for alcohol problems. © 2015 Society for the Study of Addiction.

  4. 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

  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. Meta-analysis of randomized clinical trials in the era of individual patient data sharing.

    Science.gov (United States)

    Kawahara, Takuya; Fukuda, Musashi; Oba, Koji; Sakamoto, Junichi; Buyse, Marc

    2018-01-12

    Individual patient data (IPD) meta-analysis is considered to be a gold standard when the results of several randomized trials are combined. Recent initiatives on sharing IPD from clinical trials offer unprecedented opportunities for using such data in IPD meta-analyses. First, we discuss the evidence generated and the benefits obtained by a long-established prospective IPD meta-analysis in early breast cancer. Next, we discuss a data-sharing system that has been adopted by several pharmaceutical sponsors. We review a number of retrospective IPD meta-analyses that have already been proposed using this data-sharing system. Finally, we discuss the role of data sharing in IPD meta-analysis in the future. Treatment effects can be more reliably estimated in both types of IPD meta-analyses than with summary statistics extracted from published papers. Specifically, with rich covariate information available on each patient, prognostic and predictive factors can be identified or confirmed. Also, when several endpoints are available, surrogate endpoints can be assessed statistically. Although there are difficulties in conducting, analyzing, and interpreting retrospective IPD meta-analysis utilizing the currently available data-sharing systems, data sharing will play an important role in IPD meta-analysis in the future.

  7. Propensity Score-Based Approaches to Confounding by Indication in Individual Patient Data Meta-Analysis: Non-Standardized Treatment for Multidrug Resistant Tuberculosis.

    Directory of Open Access Journals (Sweden)

    Gregory J Fox

    Full Text Available In the absence of randomized clinical trials, meta-analysis of individual patient data (IPD from observational studies may provide the most accurate effect estimates for an intervention. However, confounding by indication remains an important concern that can be addressed by incorporating individual patient covariates in different ways. We compared different analytic approaches to account for confounding in IPD from patients treated for multi-drug resistant tuberculosis (MDR-TB.Two antibiotic classes were evaluated, fluoroquinolones--considered the cornerstone of effective MDR-TB treatment--and macrolides, which are known to be safe, yet are ineffective in vitro. The primary outcome was treatment success against treatment failure, relapse or death. Effect estimates were obtained using multivariable and propensity-score based approaches.Fluoroquinolone antibiotics were used in 28 included studies, within which 6,612 patients received a fluoroquinolone and 723 patients did not. Macrolides were used in 15 included studies, within which 459 patients received this class of antibiotics and 3,670 did not. Both standard multivariable regression and propensity score-based methods resulted in similar effect estimates for early and late generation fluoroquinolones, while macrolide antibiotics use was associated with reduced treatment success.In this individual patient data meta-analysis, standard multivariable and propensity-score based methods of adjusting for individual patient covariates for observational studies yielded produced similar effect estimates. Even when adjustment is made for potential confounding, interpretation of adjusted estimates must still consider the potential for residual bias.

  8. Grain yield increase in cereal variety mixtures: A meta-analysis of field trials

    DEFF Research Database (Denmark)

    Kiær, Lars Pødenphant; Skovgaard, Ib; Østergård, Hanne

    2009-01-01

    on grain yield. To investigate the prevalence and preconditions for positive mixing effects, reported grain yields of variety mixtures and pure variety stands were obtained from previously published variety trials, converted into relative mixing effects and combined using meta-analysis. Furthermore...... as meeting the criteria for inclusion in the meta-analysis; on the other hand, nearly 200 studies were discarded. The accepted studies reported results on both winter and spring types of each crop species. Relative mixing effects ranged from 30% to 100% with an overall meta-estimate of at least 2.7% (p

  9. Meta-analysis of non-randomized studies in interventional cardiology: a critical appraisal

    Directory of Open Access Journals (Sweden)

    Eliano Pio Navarese

    2009-12-01

    Full Text Available Utilisation of meta-analysis is becoming more and more common in interventional cardiology. The aim of this statistical approach is to collect a large number of patients from randomized clinical studies and nonrandomized registries in order to obtain a pooled estimate of the results. Nevertheless, simply pooling these results without a correct methodological approach can easily lead to biased conclusions. In this report we analyse the possible methodological drawbacks of such an approach and we suggest a simplified check-list of items to be considered in the effort of building-up a meta-analysis from non-randomized studies.

  10. 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

  11. Meta-analysis on the efficacy of foot-and-mouth disease emergency vaccination

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette; Cox, Sarah

    2011-01-01

    The objectives of this study were to provide a summary quantification of the efficacy of FMD emergency vaccination based on a systematic review and a meta-analysis of available literature, and to further discuss the suitability of this review and meta-analysis to summarize and further interpret...... the results. Peer-reviewed, symposium, and unpublished studies were considered in the analysis. Clinical protection and virological protection against foot and mouth disease were used as parameters to assess the efficacy of emergency vaccination. The clinical protection was estimated based on the appearance...... vaccine. Fortunately, no significant bias that would alter the conclusions was encountered in the analysis. Meta-analysis can be a useful tool to summarize literature results from a systematic review of the efficacy of foot and mouth disease emergency vaccination....

  12. Meta-analysis on the efficacy of foot-and-mouth disease emergency vaccination

    DEFF Research Database (Denmark)

    Hisham Beshara Halasa, Tariq; Boklund, Anette; Cox, S.

    2012-01-01

    The objectives of this study were to provide a summary quantification of the efficacy of FMD emergency vaccination based on a systematic review and a meta-analysis of available literature, and to further discuss the suitability of this review and meta-analysis to summarize and further interpret...... the results. Peer-reviewed, symposium, and unpublished studies were considered in the analysis. Clinical protection and virological protection against foot and mouth disease were used as parameters to assess the efficacy of emergency vaccination. The clinical protection was estimated based on the appearance...... vaccine. Fortunately, no significant bias that would alter the conclusions was encountered in the analysis. Meta-analysis showed to be a useful tool to summarize literature results from a systematic review of the efficacy of foot and mouth disease emergency vaccination....

  13. GPS Satellite Clock Estimation Every 30 Seconds and Application to Accurate Absolute Positioning

    National Research Council Canada - National Science Library

    Han, Shin

    1998-01-01

    .... The most common method to obtain very accurate positions with GPS is to apply double-differencing procedures whereby GPS satellite signals are differenced at a station and these differences are again...

  14. The Impact of Effect Size Heterogeneity on Meta-Analysis: A Monte Carlo Experiment

    NARCIS (Netherlands)

    Koetse, Mark J.; Florax, Raymond J.G.M.; Groot, de Henri L.F.

    2007-01-01

    In this paper we use Monte Carlo simulation to investigate the impact of effect size heterogeneity on the results of a meta-analysis. Specifically, we address the small sample behaviour of the OLS, the fixed effects regression and the mixed effects meta-estimators under three alternative scenarios

  15. A Meta-Analysis of Behavioral Parent Training for Children with Attention Deficit Hyperactivity Disorder

    Science.gov (United States)

    Lee, Pei-chin; Niew, Wern-ing; Yang, Hao-jan; Chen, Vincent Chin-hung; Lin, Keh-chung

    2012-01-01

    This meta-analysis examined the effect of behavioral parent training on child and parental outcomes for children with attention deficit hyperactivity disorder. Meta-analytic procedures were used to estimate the effect of behavioral parent training on children with attention deficit hyperactivity disorder. Variables moderating the intervention…

  16. Influence of Weight Reduction on Blood Pressure; A Meta-analysis of Randomized Controlled Trials

    NARCIS (Netherlands)

    Neter, J.E.; Stam, B.E.; Kok, F.J.; Grobbee, D.E.; Geleijnse, J.M.

    2003-01-01

    Increased body weight is a strong risk factor for hypertension. A meta-analysis of randomized controlled trials was performed to estimate the effect of weight reduction on blood pressure overall and in population subgroups. Twenty-five randomized, controlled trials (comprising 34 strata) published

  17. Meta-Analysis of Results from Quantitative Trait Loci Mapping Studies on Pig Chromosome 4

    NARCIS (Netherlands)

    Moraes Silva, De K.M.; Bastiaansen, J.W.M.; Knol, E.F.; Merks, J.W.M.; Lopes, P.S.; Guimaraes, R.M.; Arendonk, van J.A.M.

    2011-01-01

    Meta-analysis of results from multiple studies could lead to more precise quantitative trait loci (QTL) position estimates compared to the individual experiments. As the raw data from many different studies are not readily available, the use of results from published articles may be helpful. In this

  18. Meta-analysis for quantitative microbiological risk assessments and benchmarking data

    NARCIS (Netherlands)

    Besten, den H.M.W.; Zwietering, M.H.

    2012-01-01

    Meta-analysis studies are increasingly being conducted in the food microbiology area to quantitatively integrate the findings of many individual studies on specific questions or kinetic parameters of interest. Meta-analyses provide global estimates of parameters and quantify their variabilities, and

  19. Post-stroke infection: a systematic review and meta-analysis

    NARCIS (Netherlands)

    Westendorp, Willeke F.; Nederkoorn, Paul J.; Vermeij, Jan-Dirk; Dijkgraaf, Marcel G.; van de Beek, Diederik

    2011-01-01

    stroke is the main cause of disability in high-income countries, and ranks second as a cause of death worldwide. Patients with acute stroke are at risk for infections, but reported post-stroke infection rates vary considerably. We performed a systematic review and meta-analysis to estimate the

  20. The effects of an edgeline on speed and lateral position: a meta-analysis

    NARCIS (Netherlands)

    van Driel, Cornelie J.G.; Davidse, Ragnhild J.; van Maarseveen, Martin F.A.M.

    2004-01-01

    This paper presents a meta-analysis of studies that have evaluated the effects of an edgeline on speed and lateral position of motorised road users. Together with many other study characteristics, 41 estimates of the effects of an edgeline on speed and 65 on lateral position were extracted from the

  1. Individual-based versus aggregate meta-analysis in multi-database studies of pregnancy outcomes

    DEFF Research Database (Denmark)

    Selmer, R.; Haglund, B.; Furu, K

    2016-01-01

    Purpose: Compare analyses of a pooled data set on the individual level with aggregate meta-analysis in a multi-database study. Methods: We reanalysed data on 2.3 million births in a Nordic register based cohort study. We compared estimated odds ratios (OR) for the effect of selective serotonin re...

  2. A meta-analysis of the effect of education on social capital

    NARCIS (Netherlands)

    Huang, J.; Maassen van den Brink, H.; Groot, W.

    2009-01-01

    To assess the empirical estimates of the effect of education on social trust and social participation - the basic dimensions of individual social capital - a meta-analysis is applied, synthesizing 154 evaluations on social trust, and 286 evaluations on social participation. The publication bias

  3. Dietary fiber and blood pressure. A meta-analysis of randomized placebo-controlled trials

    NARCIS (Netherlands)

    Streppel, M.T.; Arends, L.R.; Veer, van 't P.; Grobbee, D.E.; Geleijnse, J.M.

    2005-01-01

    Background: Dietary fiber is part of a healthy diet and may exert a protective effect in the cardiovascular system. The effect of fiber intake on blood pressure (BP) has not yet been established. Methods: We performed a meta-analysis of randomized placebo-controlled trials to estimate the effect of

  4. Prevalence of Intellectual Disability: A Meta-Analysis of Population-Based Studies

    Science.gov (United States)

    Maulik, Pallab K.; Mascarenhas, Maya N.; Mathers, Colin D.; Dua, Tarun; Saxena, Shekhar

    2011-01-01

    Intellectual disability is an extremely stigmatizing condition and involves utilization of large public health resources, but most data about its burden is based on studies conducted in developed countries. The aim of this meta-analysis was to collate data from published literature and estimate the prevalence of intellectual disability across all…

  5. A New Method of Measuring Online Media Advertising Effectiveness: Prospective Meta-Analysis in Marketing

    NARCIS (Netherlands)

    G. Liberali (Gui); G.L. Urban (Glen); B.G.C. Dellaert (Benedict); C. Tucker (Catherine); Y. Bart (Yakov); S. Stremersch (Stefan)

    2016-01-01

    textabstractThe authors introduce a new method, prospective meta-analysis in marketing (PMM), to estimate consumer response to online advertising on a large and adaptive scale. They illustrate their approach in a field study in the U.S., China and the Netherlands, covering equivalent ad content on

  6. Prevalence of oropharyngeal dysphagia in Parkinson’s disease : A meta-analysis

    NARCIS (Netherlands)

    Bastiaan Bloem; Johanna Kalf; Marten Munneke; Bert de Swart

    2012-01-01

    Dysphagia is a potentially harmful feature, also in Parkinson's disease (PD). As published prevalence rates vary widely, we aimed to estimate the prevalence of oropharyngeal dysphagia in PD in a meta-analysis. We conducted a systematic literature search in February 2011 and two independent reviewers

  7. Prevalence of oropharyngeal dysphagia in Parkinson's disease: a meta-analysis.

    NARCIS (Netherlands)

    Kalf, J.G.; Swart, B.J.M. de; Bloem, B.R.; Munneke, M.

    2012-01-01

    Dysphagia is a potentially harmful feature, also in Parkinson's disease (PD). As published prevalence rates vary widely, we aimed to estimate the prevalence of oropharyngeal dysphagia in PD in a meta-analysis. We conducted a systematic literature search in February 2011 and two independent reviewers

  8. Does stereotype threat influence performance of girls in stereotyped domains? : A meta-analysis

    NARCIS (Netherlands)

    Flore, P.C.; Wicherts, J.M.

    2015-01-01

    Although the effect of stereotype threat concerning women and mathematics has been subject to various systematic reviews, none of them have been performed on the sub-population of children and adolescents. In this meta-analysis we estimated the effects of stereotype threat on performance of girls on

  9. Systematic review and meta-analysis of homicide recidivism and Schizophrenia

    Science.gov (United States)

    2014-01-01

    Background The aim of this study was to estimate the proportion of homicide recidivists among population studies of homicide offenders with schizophrenia. Methods Systematic review and meta-analysis of published studies of homicide associated with schizophrenia conducted in defined populations and indexed in Medline, PsychINFO, or Embase between January 1960 and November 2013. Published data was supplemented with unpublished data about recidivism obtained by personal communication from the authors of published studies of homicide and schizophrenia. Random effects meta-analysis was used to calculate a pooled estimate of the proportion of homicide recidivists. Results Three studies reported that 4.3%, 4.5%, and 10.7% of homicide offenders with schizophrenia had committed an earlier homicide. Unpublished data were obtained from the authors of 11 studies of homicide in schizophrenia published in English between 1980 and 2013. The authors of 2 studies reported a single case of homicide recidivism and the authors of 9 studies reported no cases. The rates of homicide recidivism between studies were highly heterogeneous (I-square = 79). The pooled estimate of the proportion of homicide offenders with schizophrenia who had committed an earlier homicide was 2.3% (95% CI (Confidence Interval) 0.07% to 7.2%), a figure that was not reported in any individual study. The pooled proportion of homicide recidivists from published reports was more than ten times greater (8.6%, 95% CI 5.7%-12.9%) than the pooled proportion of homicide recidivists estimated from data provided by personal communication (0.06%, 95% CI 0.02% to 1.8%). Conclusions In most jurisdictions, homicide recidivism by people with schizophrenia is less common than published reports have suggested. The reasons for the variation in the rates of homicide recidivism between studies are unclear, although in most jurisdictions long-term secure treatment and supervision after release appears to be effective in

  10. Systematic review and meta-analysis of homicide recidivism and schizophrenia.

    Science.gov (United States)

    Golenkov, Andrei; Nielssen, Olav; Large, Matthew

    2014-02-18

    The aim of this study was to estimate the proportion of homicide recidivists among population studies of homicide offenders with schizophrenia. Systematic review and meta-analysis of published studies of homicide associated with schizophrenia conducted in defined populations and indexed in Medline, PsychINFO, or Embase between January 1960 and November 2013. Published data was supplemented with unpublished data about recidivism obtained by personal communication from the authors of published studies of homicide and schizophrenia. Random effects meta-analysis was used to calculate a pooled estimate of the proportion of homicide recidivists. Three studies reported that 4.3%, 4.5%, and 10.7% of homicide offenders with schizophrenia had committed an earlier homicide. Unpublished data were obtained from the authors of 11 studies of homicide in schizophrenia published in English between 1980 and 2013. The authors of 2 studies reported a single case of homicide recidivism and the authors of 9 studies reported no cases. The rates of homicide recidivism between studies were highly heterogeneous (I-square = 79). The pooled estimate of the proportion of homicide offenders with schizophrenia who had committed an earlier homicide was 2.3% (95% CI (Confidence Interval) 0.07% to 7.2%), a figure that was not reported in any individual study. The pooled proportion of homicide recidivists from published reports was more than ten times greater (8.6%, 95% CI 5.7%-12.9%) than the pooled proportion of homicide recidivists estimated from data provided by personal communication (0.06%, 95% CI 0.02% to 1.8%). In most jurisdictions, homicide recidivism by people with schizophrenia is less common than published reports have suggested. The reasons for the variation in the rates of homicide recidivism between studies are unclear, although in most jurisdictions long-term secure treatment and supervision after release appears to be effective in preventing homicide recidivism. A prospective study

  11. Kaplan-Meier Survival Analysis Overestimates the Risk of Revision Arthroplasty: A Meta-analysis.

    Science.gov (United States)

    Lacny, Sarah; Wilson, Todd; Clement, Fiona; Roberts, Derek J; Faris, Peter D; Ghali, William A; Marshall, Deborah A

    2015-11-01

    Although Kaplan-Meier survival analysis is commonly used to estimate the cumulative incidence of revision after joint arthroplasty, it theoretically overestimates the risk of revision in the presence of competing risks (such as death). Because the magnitude of overestimation is not well documented, the potential associated impact on clinical and policy decision-making remains unknown. We performed a meta-analysis to answer the following questions: (1) To what extent does the Kaplan-Meier method overestimate the cumulative incidence of revision after joint replacement compared with alternative competing-risks methods? (2) Is the extent of overestimation influenced by followup time or rate of competing risks? We searched Ovid MEDLINE, EMBASE, BIOSIS Previews, and Web of Science (1946, 1980, 1980, and 1899, respectively, to October 26, 2013) and included article bibliographies for studies comparing estimated cumulative incidence of revision after hip or knee arthroplasty obtained using both Kaplan-Meier and competing-risks methods. We excluded conference abstracts, unpublished studies, or studies using simulated data sets. Two reviewers independently extracted data and evaluated the quality of reporting of the included studies. Among 1160 abstracts identified, six studies were included in our meta-analysis. The principal reason for the steep attrition (1160 to six) was that the initial search was for studies in any clinical area that compared the cumulative incidence estimated using the Kaplan-Meier versus competing-risks methods for any event (not just the cumulative incidence of hip or knee revision); we did this to minimize the likelihood of missing any relevant studies. We calculated risk ratios (RRs) comparing the cumulative incidence estimated using the Kaplan-Meier method with the competing-risks method for each study and used DerSimonian and Laird random effects models to pool these RRs. Heterogeneity was explored using stratified meta-analyses and

  12. Determining Sample Size for Accurate Estimation of the Squared Multiple Correlation Coefficient.

    Science.gov (United States)

    Algina, James; Olejnik, Stephen

    2000-01-01

    Discusses determining sample size for estimation of the squared multiple correlation coefficient and presents regression equations that permit determination of the sample size for estimating this parameter for up to 20 predictor variables. (SLD)

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

    Science.gov (United States)

    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.

  14. Smoking and risk of colonic diverticulosis: A meta-analysis

    Directory of Open Access Journals (Sweden)

    K Wijarnpreecha

    2018-01-01

    Full Text Available Background/Objectives: The possible relationship between smoking and risk of colonic diverticulosis has been suggested by recent epidemiological studies, although the results were inconsistent. This meta-analysis was conducted to summarize all available data. Methods: A comprehensive literature review was conducted using the MEDLINE and EMBASE databases through May 2017 to identify all studies that compared the risk of colonic diverticulosis among current and former smokers versus nonsmokers. Effect estimates from each study were extracted and combined together using the random-effect, generic inverse variance method of DerSimonian and Laird. Results: Of 465 potentially eligible articles, three prospective cohort studies with 130,520 participants met the eligibility criteria and were included in the meta-analysis. The risk of colonic diverticulosis in current smokers was significantly higher than nonsmokers with the pooled risks ratio of 1.46 (95% confidence interval [CI], 1.13–1.89. However, the risk of colonic diverticulosis in former smokers was not significantly higher than nonsmokers with the pooled risk ratio of 1.13 (95% CI, 0.88–1.44. Conclusions: A significantly increased risk of colonic diverticulosis among current smokers is demonstrated in this study.

  15. Multiple Sclerosis Increases Fracture Risk: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Guixian Dong

    2015-01-01

    Full Text Available Purpose. The association between multiple sclerosis (MS and fracture risk has been reported, but results of previous studies remain controversial and ambiguous. To assess the association between MS and fracture risk, a meta-analysis was performed. Method. Based on comprehensive searches of the PubMed, Embase, and Web of Science, we identified outcome data from all articles estimating the association between MS and fracture risk. The pooled risk ratios (RRs with 95% confidence intervals (CIs were calculated. Results. A significant association between MS and fracture risk was found. This result remained statistically significant when the adjusted RRs were combined. Subgroup analysis stratified by the site of fracture suggested significant associations between MS and tibia fracture risk, femur fracture risk, hip fracture risk, pelvis fracture risk, vertebrae fracture risk, and humerus fracture risk. In the subgroup analysis by gender, female MS patients had increased fracture risk. When stratified by history of drug use, use of antidepressants, hypnotics/anxiolytics, anticonvulsants, and glucocorticoids increased the risk of fracture risk in MS patients. Conclusions. This meta-analysis demonstrated that MS was significantly associated with fracture risk.

  16. 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.

  17. 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.

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

    Science.gov (United States)

    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.

  19. Prevalence of autism spectrum disorder phenomenology in genetic disorders: a systematic review and meta-analysis.

    Science.gov (United States)

    Richards, Caroline; Jones, Christopher; Groves, Laura; Moss, Jo; Oliver, Chris

    2015-10-01

    Autism spectrum disorder (ASD) phenomenology is reported to be more common in individuals with some genetic syndromes than in the general population; however, no meta-analysis has provided prevalence data within and between syndromes. In this systematic review and meta-analysis, we aimed to synthesise data from a wide range of papers to provide accurate estimates about ASD phenomenology in genetic and metabolic syndromes. We identified syndromes reported as most likely to be associated with ASD. We searched Ovid PsycINFO, Ovid MEDLINE, Ovid Embase, and PubMed Central for English-language papers published from database creation up to early 2014 with use of syndrome-specific keywords and a set of ASD keywords. We screened and extracted papers that had ASD prevalence data for ten or more people within a genetic syndrome. With use of a prespecified set of reliable criteria, we applied quality weighting to papers and estimated a quality-effects prevalence of ASD phenomenology for each syndrome. We then calculated relative risks to compare ASD between all syndromes and also calculated odds ratios to compare prevalence with the general population taking the current estimate of one in 68 people. We identified 168 papers reporting the prevalence of ASD phenomenology and found widely varying methods and quality of data. Quality-weighted effect prevalence estimates of ASD phenomenology were established for Rett's syndrome (female individuals only 61%), Cohen's syndrome (54%), Cornelia de Lange syndrome (43%), tuberous sclerosis complex (36%), Angelman's syndrome (34%), CHARGE syndrome (30%), fragile X syndrome (male individuals only 30%; mixed sex 22%), neurofibromatosis type 1 (18%), Down's syndrome (16%), Noonan's syndrome (15%), Williams' syndrome (12%), and 22q11.2 deletion syndrome (11%). Relative risks and the odds ratio compared with the general population were highest for Rett's syndrome and Cohen's syndrome. In all syndromes, odds ratios showed ASD phenomenology to

  20. Global burden of human mycetoma: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Wendy W J van de Sande

    2013-11-01

    Full Text Available Mycetoma is a chronic infectious disease of the subcutaneous tissue with a high morbidity. This disease has been reported from countries between 30°N and 15°S since 1840 but the exact burden of disease is not known. It is currently unknown what the incidence, prevalence and the number of reported cases per year per country is. In order to estimate what the global burden of mycetoma is, a meta-analysis was performed. In total 50 studies were included, which resulted in a total of 8763 mycetoma cases. Most cases were found in men between 11 and 40 years of age. The foot was most commonly affected. Most cases were reported from Mexico, Sudan and India. Madurella mycetomatis was the most prevalent causative agent world-wide, followed by Actinomadura madurae, Streptomyces somaliensis, Actinomadura pelletieri, Nocardia brasiliensis and Nocardia asteroides. Although this study represents a first indication of the global burden on mycetoma, the actual burden is probably much higher. In this study only cases reported to literature could be used and most of these cases were found by searching archives from a single hospital in a single city of that country. By erecting (international surveillance programs a more accurate estimation of the global burden on mycetoma can be obtained.

  1. The prevalence of Chlamydia trachomatis infection in Australia: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Lewis Dyani

    2012-05-01

    Full Text Available Abstract Background Chlamydia trachomatis is a common sexually transmitted infection in Australia. This report aims to measure the burden of chlamydia infection by systematically reviewing reports on prevalence in Australian populations. Methods Electronic databases and conference websites were searched from 1997–2011 using the terms ‘Chlamydia trachomatis’ OR ‘chlamydia’ AND ‘prevalence’ OR ‘epidemiology’ AND ‘Australia’. Reference lists were checked and researchers contacted for additional literature. Studies were categorised by setting and participants, and meta-analysis conducted to determine pooled prevalence estimates for each category. Results Seventy-six studies met the inclusion criteria for the review. There was a high level of heterogeneity between studies; however, there was a trend towards higher chlamydia prevalence in younger populations, Indigenous Australians, and those attending sexual health centres. In community or general practice settings, pooled prevalence for women Conclusions Chlamydia trachomatis infections are a significant health burden in Australia; however, accurate estimation of chlamydia prevalence in Australian sub-populations is limited by heterogeneity within surveyed populations, and variations in sampling methodologies and data reporting. There is a need for more large, population-based studies and prospective cohort studies to compliment mandatory notification data.

  2. Bayesian bivariate meta-analysis of diagnostic test studies using integrated nested Laplace approximations.

    Science.gov (United States)

    Paul, M; Riebler, A; Bachmann, L M; Rue, H; Held, L

    2010-05-30

    For bivariate meta-analysis of diagnostic studies, likelihood approaches are very popular. However, they often run into numerical problems with possible non-convergence. In addition, the construction of confidence intervals is controversial. Bayesian methods based on Markov chain Monte Carlo (MCMC) sampling could be used, but are often difficult to implement, and require long running times and diagnostic convergence checks. Recently, a new Bayesian deterministic inference approach for latent Gaussian models using integrated nested Laplace approximations (INLA) has been proposed. With this approach MCMC sampling becomes redundant as the posterior marginal distributions are directly and accurately approximated. By means of a real data set we investigate the influence of the prior information provided and compare the results obtained by INLA, MCMC, and the maximum likelihood procedure SAS PROC NLMIXED. Using a simulation study we further extend the comparison of INLA and SAS PROC NLMIXED by assessing their performance in terms of bias, mean-squared error, coverage probability, and convergence rate. The results indicate that INLA is more stable and gives generally better coverage probabilities for the pooled estimates and less biased estimates of variance parameters. The user-friendliness of INLA is demonstrated by documented R-code. Copyright (c) 2010 John Wiley & Sons, Ltd.

  3. Analysis and meta-analysis of single-case designs: an introduction.

    Science.gov (United States)

    Shadish, William R

    2014-04-01

    The last 10 years have seen great progress in the analysis and meta-analysis of single-case designs (SCDs). This special issue includes five articles that provide an overview of current work on that topic, including standardized mean difference statistics, multilevel models, Bayesian statistics, and generalized additive models. Each article analyzes a common example across articles and presents syntax or macros for how to do them. These articles are followed by commentaries from single-case design researchers and journal editors. This introduction briefly describes each article and then discusses several issues that must be addressed before we can know what analyses will eventually be best to use in SCD research. These issues include modeling trend, modeling error covariances, computing standardized effect size estimates, assessing statistical power, incorporating more accurate models of outcome distributions, exploring whether Bayesian statistics can improve estimation given the small samples common in SCDs, and the need for annotated syntax and graphical user interfaces that make complex statistics accessible to SCD researchers. The article then discusses reasons why SCD researchers are likely to incorporate statistical analyses into their research more often in the future, including changing expectations and contingencies regarding SCD research from outside SCD communities, changes and diversity within SCD communities, corrections of erroneous beliefs about the relationship between SCD research and statistics, and demonstrations of how statistics can help SCD researchers better meet their goals. Copyright © 2013 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

  4. Compact and accurate linear and nonlinear autoregressive moving average model parameter estimation using laguerre functions

    DEFF Research Database (Denmark)

    Chon, K H; Cohen, R J; Holstein-Rathlou, N H

    1997-01-01

    A linear and nonlinear autoregressive moving average (ARMA) identification algorithm is developed for modeling time series data. The algorithm uses Laguerre expansion of kernals (LEK) to estimate Volterra-Wiener kernals. However, instead of estimating linear and nonlinear system dynamics via movi...

  5. Fast and accurate estimation of the covariance between pairwise maximum likelihood distances

    Directory of Open Access Journals (Sweden)

    Manuel Gil

    2014-09-01

    Full Text Available Pairwise evolutionary distances are a model-based summary statistic for a set of molecular sequences. They represent the leaf-to-leaf path lengths of the underlying phylogenetic tree. Estimates of pairwise distances with overlapping paths covary because of shared mutation events. It is desirable to take these covariance structure into account to increase precision in any process that compares or combines distances. This paper introduces a fast estimator for the covariance of two pairwise maximum likelihood distances, estimated under general Markov models. The estimator is based on a conjecture (going back to Nei & Jin, 1989 which links the covariance to path lengths. It is proven here under a simple symmetric substitution model. A simulation shows that the estimator outperforms previously published ones in terms of the mean squared error.

  6. Epidemiology of chronic obstructive pulmonary disease in the global HIV-infected population: a systematic review and meta-analysis protocol.

    Science.gov (United States)

    Bigna, Jean Joel R; Kenne, Angeladine Malaha; Asangbeh, Serra Lem

    2017-03-29

    Evidence suggests a relationship between human immunodeficiency virus (HIV) infection and chronic obstructive pulmonary disease (COPD). Although the high burden of COPD and the HIV disease is clearly demonstrated, to the best of our knowledge, there is a lack of summary and meta-analysis data on the epidemiology of COPD in the global HIV-infected population to date. The present protocol for a systematic review and meta-analysis intends to summarize existing data on the prevalence, incidence, and risk factors of COPD in the global HIV-infected population. The present review will include cohort, cross-sectional, and case-control studies conducted among HIV infected people, which report prevalence, incidence, and factors associated with COPD or enough data for their estimation. We will consider published and unpublished studies in English and French language, regardless of geographical location. Relevant records will be searched using PubMed/Medline, and Scopus from inception to December 31st, 2016. Reference lists of eligible papers and relevant review articles will be screened. Two investigators will independently screen, select studies, and extract data, with discrepancies resolved by consensus or arbitrarily by a third investigator. Risk of bias and methodological quality of the included studies will be assessed using the Newcastle-Ottawa Scale. Funnel-plots and Egger's test will be used to determine publication bias. The study-specific estimates will be pooled through a random-effects meta-analysis model to obtain an overall summary estimate. To keep the effect of studies with extremely small or extremely large estimates on the overall estimate to a minimum, the variance of the study-specific prevalence/incidence will be stabilized with the Freeman-Tukey single arc-sine transformation. The heterogeneity will be evaluated by the χ 2 test on Cochrane's Q statistic. Results will be presented by geographic region and by antiretroviral therapy status. We plan to

  7. 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

  8. Improved Patient Size Estimates for Accurate Dose Calculations in Abdomen Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chang-Lae [Yonsei University, Wonju (Korea, Republic of)

    2017-07-15

    The radiation dose of CT (computed tomography) is generally represented by the CTDI (CT dose index). CTDI, however, does not accurately predict the actual patient doses for different human body sizes because it relies on a cylinder-shaped head (diameter : 16 cm) and body (diameter : 32 cm) phantom. The purpose of this study was to eliminate the drawbacks of the conventional CTDI and to provide more accurate radiation dose information. Projection radiographs were obtained from water cylinder phantoms of various sizes, and the sizes of the water cylinder phantoms were calculated and verified using attenuation profiles. The effective diameter was also calculated using the attenuation of the abdominal projection radiographs of 10 patients. When the results of the attenuation-based method and the geometry-based method shown were compared with the results of the reconstructed-axial-CT-image-based method, the effective diameter of the attenuation-based method was found to be similar to the effective diameter of the reconstructed-axial-CT-image-based method, with a difference of less than 3.8%, but the geometry-based method showed a difference of less than 11.4%. This paper proposes a new method of accurately computing the radiation dose of CT based on the patient sizes. This method computes and provides the exact patient dose before the CT scan, and can therefore be effectively used for imaging and dose control.

  9. Accurate single-observer passive coherent location estimation based on TDOA and DOA

    Directory of Open Access Journals (Sweden)

    Li Jing

    2014-08-01

    Full Text Available This paper investigates the problem of target position estimation with a single-observer passive coherent location (PCL system. An approach that combines angle with time difference of arrival (ATDOA is used to estimate the location of a target. Compared with the TDOA-only method which needs two steps, the proposed method estimates the target position more directly. The constrained total least squares (CTLS technique is applied in this approach. It achieves the Cramer–Rao lower bound (CRLB when the parameter measurements are subject to small Gaussian-distributed errors. Performance analysis and the CRLB of this approach are also studied. Theory verifies that the ATDOA method gets a lower CRLB than the TDOA-only method with the same TDOA measuring error. It can also be seen that the position of the target affects estimating precision. At the same time, the locations of transmitters affect the precision and its gradient direction. Compared with the TDOA, the ATDOA method can obtain more precise target position estimation. Furthermore, the proposed method accomplishes target position estimation with a single transmitter, while the TDOA-only method needs at least four transmitters to get the target position. Furthermore, the transmitters’ position errors also affect precision of estimation regularly.

  10. An accurate estimation and optimization of bottom hole back pressure in managed pressure drilling

    Directory of Open Access Journals (Sweden)

    Boniface Aleruchi ORIJI

    2017-06-01

    Full Text Available Managed Pressure Drilling (MPD utilizes a method of applying back pressure to compensate for wellbore pressure losses during drilling. Using a single rheological (Annular Frictional Pressure Losses, AFPL model to estimate the backpressure in MPD operations for all sections of the well may not yield the best result. Each section of the hole was therefore treated independently in this study as data from a case study well were used. As the backpressure is a function of hydrostatic pressure, pore pressure and AFPL, three AFPL models (Bingham plastic, Power law and Herschel Bulkley models were utilized in estimating the backpressure. The estimated backpressure values were compared to the actual field backpressure values in order to obtain the optimum backpressure at the various well depths. The backpressure values estimated by utilizing the power law AFPL model gave the best result for the 12 1/4" hole section (average error % of 1.855% while the back pressures estimated by utilizing the Herschel Bulkley AFPL model gave the best result for the 8 1/2" hole section (average error % of 12.3%. The study showed that for hole sections of turbulent annular flow, the power law AFPL model fits best for estimating the required backpressure while for hole sections of laminar annular flow, the Herschel Bulkley AFPL model fits best for estimating the required backpressure.

  11. 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....

  12. The Efficacy of Injury Prevention Programs in Adolescent Team Sports: A Meta-analysis.

    Science.gov (United States)

    Soomro, Najeebullah; Sanders, Ross; Hackett, Daniel; Hubka, Tate; Ebrahimi, Saahil; Freeston, Jonathan; Cobley, Stephen

    2016-09-01

    Intensive sport participation in childhood and adolescence is an established cause of acute and overuse injury. Interventions and programs designed to prevent such injuries are important in reducing individual and societal costs associated with treatment and recovery. Likewise, they help to maintain the accrual of positive outcomes from participation, such as cardiovascular health and skill development. To date, several studies have individually tested the effectiveness of injury prevention programs (IPPs). To determine the overall efficacy of structured multifaceted IPPs containing a combination of warm-up, neuromuscular strength, or proprioception training, targeting injury reduction rates according to risk exposure time in adolescent team sport contexts. Systematic review and meta-analysis. With established inclusion criteria, studies were searched in the following databases: Cochrane Central Register of Controlled Trials, MEDLINE, SPORTDiscus, Web of Science, EMBASE, CINAHL, and AusSportMed. The keyword search terms (including derivations) included the following: adolescents, sports, athletic injuries, prevention/warm-up programs. Eligible studies were then pooled for meta-analysis with an invariance random-effects model, with injury rate ratio (IRR) as the primary outcome. Heterogeneity among studies and publication bias were tested, and subgroup analysis examined heterogeneity sources. Across 10 studies, including 9 randomized controlled trials, a pooled overall point estimate yielded an IRR of 0.60 (95% CI = 0.48-0.75; a 40% reduction) while accounting for hours of risk exposure. Publication bias assessment suggested an 8% reduction in the estimate (IRR = 0.68, 95% CI = 0.54-0.84), and the prediction interval intimated that any study estimate could still fall between 0.33 and 1.48. Subgroup analyses identified no significant moderators, although possible influences may have been masked because of data constraints. Compared with normative practices or control

  13. 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.

  14. 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.

  15. Fast, accurate, and robust frequency offset estimation based on modified adaptive Kalman filter in coherent optical communication system

    Science.gov (United States)

    Yang, Yanfu; Xiang, Qian; Zhang, Qun; Zhou, Zhongqing; Jiang, Wen; He, Qianwen; Yao, Yong

    2017-09-01

    We propose a joint estimation scheme for fast, accurate, and robust frequency offset (FO) estimation along with phase estimation based on modified adaptive Kalman filter (MAKF). The scheme consists of three key modules: extend Kalman filter (EKF), lock detector, and FO cycle slip recovery. The EKF module estimates time-varying phase induced by both FO and laser phase noise. The lock detector module makes decision between acquisition mode and tracking mode and consequently sets the EKF tuning parameter in an adaptive manner. The third module can detect possible cycle slip in the case of large FO and make proper correction. Based on the simulation and experimental results, the proposed MAKF has shown excellent estimation performance featuring high accuracy, fast convergence, as well as the capability of cycle slip recovery.

  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. 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

  18. Accurate and efficient velocity estimation using Transmission matrix formalism based on the domain decomposition method

    Science.gov (United States)

    Wang, Benfeng; Jakobsen, Morten; Wu, Ru-Shan; Lu, Wenkai; Chen, Xiaohong

    2017-03-01

    Full waveform inversion (FWI) has been regarded as an effective tool to build the velocity model for the following pre-stack depth migration. Traditional inversion methods are built on Born approximation and are initial model dependent, while this problem can be avoided by introducing Transmission matrix (T-matrix), because the T-matrix includes all orders of scattering effects. The T-matrix can be estimated from the spatial aperture and frequency bandwidth limited seismic data using linear optimization methods. However the full T-matrix inversion method (FTIM) is always required in order to estimate velocity perturbations, which is very time consuming. The efficiency can be improved using the previously proposed inverse thin-slab propagator (ITSP) method, especially for large scale models. However, the ITSP method is currently designed for smooth media, therefore the estimation results are unsatisfactory when the velocity perturbation is relatively large. In this paper, we propose a domain decomposition method (DDM) to improve the efficiency of the velocity estimation for models with large perturbations, as well as guarantee the estimation accuracy. Numerical examples for smooth Gaussian ball models and a reservoir model with sharp boundaries are performed using the ITSP method, the proposed DDM and the FTIM. The estimated velocity distributions, the relative errors and the elapsed time all demonstrate the validity of the proposed DDM.

  19. The validation study on a three-dimensional burn estimation smart-phone application: accurate, free and fast?

    Science.gov (United States)

    Cheah, A K W; Kangkorn, T; Tan, E H; Loo, M L; Chong, S J

    2018-01-01

    Accurate total body surface area burned (TBSAB) estimation is a crucial aspect of early burn management. It helps guide resuscitation and is essential in the calculation of fluid requirements. Conventional methods of estimation can often lead to large discrepancies in burn percentage estimation. We aim to compare a new method of TBSAB estimation using a three-dimensional smart-phone application named 3D Burn Resuscitation (3D Burn) against conventional methods of estimation-Rule of Palm, Rule of Nines and the Lund and Browder chart. Three volunteer subjects were moulaged with simulated burn injuries of 25%, 30% and 35% total body surface area (TBSA), respectively. Various healthcare workers were invited to use both the 3D Burn application as well as the conventional methods stated above to estimate the volunteer subjects' burn percentages. Collective relative estimations across the groups showed that when used, the Rule of Palm, Rule of Nines and the Lund and Browder chart all over-estimated burns area by an average of 10.6%, 19.7%, and 8.3% TBSA, respectively, while the 3D Burn application under-estimated burns by an average of 1.9%. There was a statistically significant difference between the 3D Burn application estimations versus all three other modalities ( p  Burn application, although slower, allowed more accurate TBSAB measurements when compared to conventional methods. The validation study has shown that the 3D Burn application is useful in improving the accuracy of TBSAB measurement. Further studies are warranted, and there are plans to repeat the above study in a different centre overseas as part of a multi-centre study, with a view of progressing to a prospective study that compares the accuracy of the 3D Burn application against conventional methods on actual burn patients.

  20. Likelihood ratio meta-analysis: New motivation and approach for an old method.

    Science.gov (United States)

    Dormuth, Colin R; Filion, Kristian B; Platt, Robert W

    2016-03-01

    A 95% confidence interval (CI) in an updated meta-analysis may not have the expected 95% coverage. If a meta-analysis is simply updated with additional data, then the resulting 95% CI will be wrong because it will not have accounted for the fact that the earlier meta-analysis failed or succeeded to exclude the null. This situation can be avoided by using the likelihood ratio (LR) as a measure of evidence that does not depend on type-1 error. We show how an LR-based approach, first advanced by Goodman, can be used in a meta-analysis to pool data from separate studies to quantitatively assess where the total evidence points. The method works by estimating the log-likelihood ratio (LogLR) function from each study. Those functions are then summed to obtain a combined function, which is then used to retrieve the total effect estimate, and a corresponding 'intrinsic' confidence interval. Using as illustrations the CAPRIE trial of clopidogrel versus aspirin in the prevention of ischemic events, and our own meta-analysis of higher potency statins and the risk of acute kidney injury, we show that the LR-based method yields the same point estimate as the traditional analysis, but with an intrinsic confidence interval that is appropriately wider than the traditional 95% CI. The LR-based method can be used to conduct both fixed effect and random effects meta-analyses, it can be applied to old and new meta-analyses alike, and results can be presented in a format that is familiar to a meta-analytic audience. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. The Clinical Usefulness of Tuberculin Skin Test versus Interferon-Gamma Release Assays for Diagnosis of Latent Tuberculosis in HIV Patients: A Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Erfan Ayubi

    Full Text Available Accurate diagnosis of latent tuberculosis infection (LTBI is becoming increasingly concerning due to the increasing the HIV epidemic, which have increased the risk for reactivation to active tuberculosis (TB infection. LTBI is diagnosed by tuberculin skin test (TST and interferon-gamma release assays (IGRAs.The aim of the present study was to conduct a meta-analysis of published papers on the agreement (kappa between TST and QuantiFERON-TB Gold In-Tube (QFT-GIT tests for diagnosis of LTBI in HIV patient.Electronic databases including PubMed/Medline, Elsevier/Scopus and Embase/Ovid were reviewed up Jan. 2016. We performed a random effect model meta-analysis for estimation of pooled Kappa between the two methods of diagnosis. Meta regression was used for assessing potential heterogeneity and Egger's test was used for assessing small study effect and publication bias.The initial search strategy produced 6744 records. Of them, 23 cross-sectional studies met the inclusion criteria and 20 studies entered in meta-analysis. The pooled kappa was and prevalence-adjusted and bias-adjusted kappa (PABAK were 0.37 (95% CI: 0.28, 0.46 and 0.59 (0.49, 0.69. The discordance of TST-/QFT-GIT+ was more than TST+/QFT-GIT-. Kappa estimate between two tests was linearly associated with age and prevalence index and inversely associated with bias index.Fair agreement between TST and QFT-GIT makes it difficult to know whether TST is as useful as the QFT-GIT in HIV-infected patients. The higher discordance of TST-/QFT-GIT+ in compared to TST+/QFT-GIT- can induce the higher sensitivity of QFT-GIT for diagnosis LTBI in HIV patients. Disagreement between two tests can be influenced by error in measurements and prevalence of HIV.

  2. Accurate and robust phylogeny estimation based on profile distances: a study of the Chlorophyceae (Chlorophyta

    Directory of Open Access Journals (Sweden)

    Rahmann Sven

    2004-06-01

    Full Text Available Abstract Background In phylogenetic analysis we face the problem that several subclade topologies are known or easily inferred and well supported by bootstrap analysis, but basal branching patterns cannot be unambiguously estimated by the usual methods (maximum parsimony (MP, neighbor-joining (NJ, or maximum likelihood (ML, nor are they well supported. We represent each subclade by a sequence profile and estimate evolutionary distances between profiles to obtain a matrix of distances between subclades. Results Our estimator of profile distances generalizes the maximum likelihood estimator of sequence distances. The basal branching pattern can be estimated by any distance-based method, such as neighbor-joining. Our method (profile neighbor-joining, PNJ then inherits the accuracy and robustness of profiles and the time efficiency of neighbor-joining. Conclusions Phylogenetic analysis of Chlorophyceae with traditional methods (MP, NJ, ML and MrBayes reveals seven well supported subclades, but the methods disagree on the basal branching pattern. The tree reconstructed by our method is better supported and can be confirmed by known morphological characters. Moreover the accuracy is significantly improved as shown by parametric bootstrap.

  3. Complementary and alternative exercise for fibromyalgia: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Mist SD

    2013-03-01

    Full Text Available Scott David Mist, Kari Firestone, Kim Dupree Jones Fibromyalgia Research and Treatment Group, School of Nursing, Oregon Health and Science University, Portland, OR, USA Abstract: Complementary and alternative medicine includes a number of exercise modalities, such as tai chi, qigong, yoga, and a variety of lesser-known movement therapies. A meta-analysis of the current literature was conducted estimating the effect size of the different modalities, study quality and bias, and adverse events. The level of research has been moderately weak to date, but most studies report a medium-to-high effect size in pain reduction. Given the lack of adverse events, there is little risk in recommending these modalities as a critical component in a multimodal treatment plan, which is often required for fibromyalgia management. Keywords: fibromyalgia, exercise, complementary and alternative, efficacy, safety

  4. Comparing the standards of one metabolic equivalent of task in accurately estimating physical activity energy expenditure based on acceleration.

    Science.gov (United States)

    Kim, Dohyun; Lee, Jongshill; Park, Hoon Ki; Jang, Dong Pyo; Song, Soohwa; Cho, Baek Hwan; Jung, Yoo-Suk; Park, Rae-Woong; Joo, Nam-Seok; Kim, In Young

    2017-07-01

    The purpose of the study is to analyse how the standard of resting metabolic rate (RMR) affects estimation of the metabolic equivalent of task (MET) using an accelerometer. In order to investigate the effect on estimation according to intensity of activity, comparisons were conducted between the 3.5 ml O 2  · kg -1  · min -1 and individually measured resting VO 2 as the standard of 1 MET. MET was estimated by linear regression equations that were derived through five-fold cross-validation using 2 types of MET values and accelerations; the accuracy of estimation was analysed through cross-validation, Bland and Altman plot, and one-way ANOVA test. There were no significant differences in the RMS error after cross-validation. However, the individual RMR-based estimations had as many as 0.5 METs of mean difference in modified Bland and Altman plots than RMR of 3.5 ml O 2  · kg -1  · min -1 . Finally, the results of an ANOVA test indicated that the individual RMR-based estimations had less significant differences between the reference and estimated values at each intensity of activity. In conclusion, the RMR standard is a factor that affects accurate estimation of METs by acceleration; therefore, RMR requires individual specification when it is used for estimation of METs using an accelerometer.

  5. 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.

  6. Usefulness of a novel calibrated hood to determine indications for colon polypectomy: visual estimation of polyp size is not accurate.

    Science.gov (United States)

    Watanabe, Tatsuyuki; Kume, Keiichiro; Yoshikawa, Ichiro; Harada, Masaru

    2015-07-01

    Accurate measurement of polyp size during colonoscopy is important because the size is a surrogate marker of cancer, but a standardized measurement technique to measure polyp size has yet to be determined. We have developed a new device "a novel calibrated hood." We assessed polyp size by visual estimation and measurement using the calibrated hood. Patients who underwent polypectomy from November 2012 to September 2013 and who had received screening colonoscopy within 6 months prior to the polypectomy were included in this study. Polypectomy was performed attaching the calibrated hood. The endoscopist measured the polyp size using the calibrated hood. Polyp size was compared between visual estimation and measurement using the calibrated hood. Seventy-five patients with 157 polyps were included. Seventy-seven polyps fulfilled the selection criteria. Mean polyp size by visual estimation was 6.57 ± 2.15, and by using calibrated hood was 5.94 ± 1.73 (p = 0.005). There was a significant difference between measurements using the calibrated hood vs. visual estimation by inexperienced trainees; however, there was no difference in case of well-experienced endoscopists. By visual estimation, 11 of 19 polyps were decided for ≥5 mm despite being less than 5 mm, and 5 of 58 polyps were decided for estimation of polyp size is not accurate. It is important to measure the size by an objective way, and the calibrated hood is useful in measuring polyp size, from the standpoint of accurately determining indication for polypectomy.

  7. 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.

  8. Accurate Angle Estimator for High-Frame-rate 2-D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Lindskov Hansen, Kristoffer

    2016-01-01

    This paper presents a novel approach for estimating 2-D flow angles using a high-frame-rate ultrasound method. The angle estimator features high accuracy and low standard deviation (SD) over the full 360° range. The method is validated on Field II simulations and phantom measurements using...... the experimental ultrasound scanner SARUS and a flow rig before being tested in vivo. An 8-MHz linear array transducer is used with defocused beam emissions. In the simulations of a spinning disk phantom, a 360° uniform behavior on the angle estimation is observed with a median angle bias of 1.01° and a median...... angle SD of 1.8°. Similar results are obtained on a straight vessel for both simulations and measurements, where the obtained angle biases are below 1.5° with SDs around 1°. Estimated velocity magnitudes are also kept under 10% bias and 5% relative SD in both simulations and measurements. An in vivo...

  9. Do wavelet filters provide more accurate estimates of reverberation times at low frequencies

    DEFF Research Database (Denmark)

    Sobreira Seoane, Manuel A.; Pérez Cabo, David; Agerkvist, Finn T.

    2016-01-01

    the continuous wavelet transform (CTW) has been implemented using a Morlet mother function. Although in general, the wavelet filter bank performs better than the usual filters, the influence of decaying modes outside the filter bandwidth on the measurements has been detected, leading to a biased estimation...

  10. How accurate are satellite estimates of precipitation over the north Indian Ocean?

    Science.gov (United States)

    Prakash, Satya; Ramesh Kumar, M. R.; Mathew, Simi; Venkatesan, R.

    2017-10-01

    Following the launch of the Global Precipitation Measurement (GPM) Core Observatory in early 2014, motivated from the successful Tropical Rainfall Measurement Mission (TRMM) satellite, an advanced and sophisticated global multi-satellite precipitation product-Integrated Multi-satellitE Retrievals for GPM (IMERG) was released at finer spatio-temporal scales. This precipitation product has been upgraded recently after several refinements and supposed to be superior to other existing global or quasi-global multi-satellite precipitation estimates. In the present study, IMERG precipitation is comprehensively evaluated for the first time against moored buoy observations over the north Indian Ocean at hourly scale for the study period of March 2014 to December 2015. IMERG precipitation performs considerably better over the Bay of Bengal than the Arabian Sea in both detection and estimation. The systematic error in IMERG is appreciably lower by about 14%; however, it generally overestimates in-situ precipitation and also exhibits noticeable false alarms. Furthermore, IMERG essentially shows an improvement over the TRMM Multi-satellite Precipitation Analysis (TMPA) at a daily scale over the north Indian Ocean. IMERG precipitation estimates show overall promising error characteristics, but there is still a need of substantial efforts for improvement in the satellite-based precipitation estimation algorithms especially over data sparse regions such as north Indian Ocean.

  11. Meta-analysis methods for combining multiple expression profiles: comparisons, statistical characterization and an application guideline

    Science.gov (United States)

    2013-01-01

    Background As high-throughput genomic technologies become accurate and affordable, an increasing number of data sets have been accumulated in the public domain and genomic information integration and meta-analysis have become routine in biomedical research. In this paper, we focus on microarray meta-analysis, where multiple microarray studies with relevant biological hypotheses are combined in order to improve candidate marker detection. Many methods have been developed and applied in the literature, but their performance and properties have only been minimally investigated. There is currently no clear conclusion or guideline as to the proper choice of a meta-analysis method given an application; the decision essentially requires both statistical and biological considerations. Results We performed 12 microarray meta-analysis methods for combining multiple simulated expression profiles, and such methods can be categorized for different hypothesis setting purposes: (1) HS A : DE genes with non-zero effect sizes in all studies, (2) HS B : DE genes with non-zero effect sizes in one or more studies and (3) HS r : DE gene with non-zero effect in "majority" of studies. We then performed a comprehensive comparative analysis through six large-scale real applications using four quantitative statistical evaluation criteria: detection capability, biological association, stability and robustness. We elucidated hypothesis settings behind the methods and further apply multi-dimensional scaling (MDS) and an entropy measure to characterize the meta-analysis methods and data structure, respectively. Conclusions The aggregated results from the simulation study categorized the 12 methods into three hypothesis settings (HS A , HS B , and HS r ). Evaluation in real data and results from MDS and entropy analyses provided an insightful and practical guideline to the choice of the most suitable method in a given application. All source files for simulation and real data are available on

  12. Projecting meat and cereals demand for China based on a meta-analysis of income elasticities

    OpenAIRE

    Zhou, De; Yu, Xiaohua; Abler, David; Chen, Danhong

    2014-01-01

    There are many projections for China’s food demand, and the projection results differ significantly from each other. Different values for income elasticities could be a major reason. This study projects meat and cereals demand for China based on a meta-analysis of the income elasticity estimates using a collection of 143 and 240 income elasticity estimates for cereals and meat products, respectively, from 36 primary studies. We find that income elasticities for most cereals (general cereals, ...

  13. Accurate estimation of influenza epidemics using Google search data via ARGO.

    Science.gov (United States)

    Yang, Shihao; Santillana, Mauricio; Kou, S C

    2015-11-24

    Accurate real-time tracking of influenza outbreaks helps public health officials make timely and meaningful decisions that could save lives. We propose an influenza tracking model, ARGO (AutoRegression with GOogle search data), that uses publicly available online search data. In addition to having a rigorous statistical foundation, ARGO outperforms all previously available Google-search-based tracking models, including the latest version of Google Flu Trends, even though it uses only low-quality search data as input from publicly available Google Trends and Google Correlate websites. ARGO not only incorporates the seasonality in influenza epidemics but also captures changes in people's online search behavior over time. ARGO is also flexible, self-correcting, robust, and scalable, making it a potentially powerful tool that can be used for real-time tracking of other social events at multiple temporal and spatial resolutions.

  14. CUFID-query: accurate network querying through random walk based network flow estimation.

    Science.gov (United States)

    Jeong, Hyundoo; Qian, Xiaoning; Yoon, Byung-Jun

    2017-12-28

    Functional modules in biological networks consist of numerous biomolecules and their complicated interactions. Recent studies have shown that biomolecules in a functional module tend to have similar interaction patterns and that such modules are often conserved across biological networks of different species. As a result, such conserved functional modules can be identified through comparative analysis of biological networks. In this work, we propose a novel network querying algorithm based on the CUFID (Comparative network analysis Using the steady-state network Flow to IDentify orthologous proteins) framework combined with an efficient seed-and-extension approach. The proposed algorithm, CUFID-query, can accurately detect conserved functional modules as small subnetworks in the target network that are expected to perform similar functions to the given query functional module. The CUFID framework was recently developed for probabilistic pairwise global comparison of biological networks, and it has been applied to pairwise global network alignment, where the framework was shown to yield accurate network alignment results. In the proposed CUFID-query algorithm, we adopt the CUFID framework and extend it for local network alignment, specifically to solve network querying problems. First, in the seed selection phase, the proposed method utilizes the CUFID framework to compare the query and the target networks and to predict the probabilistic node-to-node correspondence between the networks. Next, the algorithm selects and greedily extends the seed in the target network by iteratively adding nodes that have frequent interactions with other nodes in the seed network, in a way that the conductance of the extended network is maximally reduced. Finally, CUFID-query removes irrelevant nodes from the querying results based on the personalized PageRank vector for the induced network that includes the fully extended network and its neighboring nodes. Through extensive

  15. Accurate estimation of dose distributions inside an eye irradiated with 106Ru plaques

    International Nuclear Information System (INIS)

    Brualla, L.; Sauerwein, W.; Sempau, J.; Zaragoza, F.J.; Wittig, A.

    2013-01-01

    Background: Irradiation of intraocular tumors requires dedicated techniques, such as brachytherapy with 106 Ru plaques. The currently available treatment planning system relies on the assumption that the eye is a homogeneous water sphere and on simplified radiation transport physics. However, accurate dose distributions and their assessment demand better models for both the eye and the physics. Methods: The Monte Carlo code PENELOPE, conveniently adapted to simulate the beta decay of 106 Ru over 106 Rh into 106 Pd, was used to simulate radiation transport based on a computerized tomography scan of a patient's eye. A detailed geometrical description of two plaques (models CCA and CCB) from the manufacturer BEBIG was embedded in the computerized tomography scan. Results: The simulations were firstly validated by comparison with experimental results in a water phantom. Dose maps were computed for three plaque locations on the eyeball. From these maps, isodose curves and cumulative dose-volume histograms in the eye and for the structures at risk were assessed. For example, it was observed that a 4-mm anterior displacement with respect to a posterior placement of a CCA plaque for treating a posterior tumor would reduce from 40 to 0% the volume of the optic disc receiving more than 80 Gy. Such a small difference in anatomical position leads to a change in the dose that is crucial for side effects, especially with respect to visual acuity. The radiation oncologist has to bring these large changes in absorbed dose in the structures at risk to the attention of the surgeon, especially when the plaque has to be positioned close to relevant tissues. Conclusion: The detailed geometry of an eye plaque in computerized and segmented tomography of a realistic patient phantom was simulated accurately. Dose-volume histograms for relevant anatomical structures of the eye and the orbit were obtained with unprecedented accuracy. This represents an important step toward an optimized

  16. Raman spectroscopy for highly accurate estimation of the age of refrigerated porcine muscle

    Science.gov (United States)

    Timinis, Constantinos; Pitris, Costas

    2016-03-01

    The high water content of meat, combined with all the nutrients it contains, make it vulnerable to spoilage at all stages of production and storage even when refrigerated at 5 °C. A non-destructive and in situ tool for meat sample testing, which could provide an accurate indication of the storage time of meat, would be very useful for the control of meat quality as well as for consumer safety. The proposed solution is based on Raman spectroscopy which is non-invasive and can be applied in situ. For the purposes of this project, 42 meat samples from 14 animals were obtained and three Raman spectra per sample were collected every two days for two weeks. The spectra were subsequently processed and the sample age was calculated using a set of linear differential equations. In addition, the samples were classified in categories corresponding to the age in 2-day steps (i.e., 0, 2, 4, 6, 8, 10, 12 or 14 days old), using linear discriminant analysis and cross-validation. Contrary to other studies, where the samples were simply grouped into two categories (higher or lower quality, suitable or unsuitable for human consumption, etc.), in this study, the age was predicted with a mean error of ~ 1 day (20%) or classified, in 2-day steps, with 100% accuracy. Although Raman spectroscopy has been used in the past for the analysis of meat samples, the proposed methodology has resulted in a prediction of the sample age far more accurately than any report in the literature.

  17. ACCURATE ESTIMATION OF ORIENTATION PARAMETERS OF UAV IMAGES THROUGH IMAGE REGISTRATION WITH AERIAL OBLIQUE IMAGERY

    Directory of Open Access Journals (Sweden)

    F. A. Onyango

    2017-05-01

    Full Text Available Unmanned Aerial Vehicles (UAVs have gained popularity in acquiring geotagged, low cost and high resolution images. However, the images acquired by UAV-borne cameras often have poor georeferencing information, because of the low quality on-board Global Navigation Satellite System (GNSS receiver. In addition, lightweight UAVs have a limited payload capacity to host a high quality on-board Inertial Measurement Unit (IMU. Thus, orientation parameters of images acquired by UAV-borne cameras may not be very accurate. Poorly georeferenced UAV images can be correctly oriented using accurately oriented airborne images capturing a similar scene by finding correspondences between the images. This is not a trivial task considering the image pairs have huge variations in scale, perspective and illumination conditions. This paper presents a procedure to successfully register UAV and aerial oblique imagery. The proposed procedure implements the use of the AKAZE interest operator for feature extraction in both images. Brute force is implemented to find putative correspondences and later on Lowe’s ratio test (Lowe, 2004 is used to discard a significant number of wrong matches. In order to filter out the remaining mismatches, the putative correspondences are used in the computation of multiple homographies, which aid in the reduction of outliers significantly. In order to increase the number and improve the quality of correspondences, the impact of pre-processing the images using the Wallis filter (Wallis, 1974 is investigated. This paper presents the test results of different scenarios and the respective accuracies compared to a manual registration of the finally computed fundamental and essential matrices that encode the orientation parameters of the UAV images with respect to the aerial images.

  18. Quantification of Food Waste Disposal in the United States: A Meta-Analysis.

    Science.gov (United States)

    Thyberg, Krista L; Tonjes, David J; Gurevitch, Jessica

    2015-12-15

    Food waste has major consequences for social, nutritional, economic, and environmental issues, and yet the amount of food waste disposed in the U.S. has not been accurately quantified. We introduce the transparent and repeatable methods of meta-analysis and systematic reviewing to determine how much food is discarded in the U.S., and to determine if specific factors drive increased disposal. The aggregate proportion of food waste in U.S. municipal solid waste from 1995 to 2013 was found to be 0.147 (95% CI 0.137-0.157) of total disposed waste, which is lower than that estimated by U.S. Environmental Protection Agency for the same period (0.176). The proportion of food waste increased significantly with time, with the western U.S. region having consistently and significantly higher proportions of food waste than other regions. There were no significant differences in food waste between rural and urban samples, or between commercial/institutional and residential samples. The aggregate disposal rate for food waste was 0.615 pounds (0.279 kg) (95% CI 0.565-0.664) of food waste disposed per person per day, which equates to over 35.5 million tons (32.2 million tonnes) of food waste disposed annually in the U.S.

  19. Are satellite based rainfall estimates accurate enough for crop modelling under Sahelian climate?

    Science.gov (United States)

    Ramarohetra, J.; Sultan, B.

    2012-04-01

    Agriculture is considered as the most climate dependant human activity. In West Africa and especially in the sudano-sahelian zone, rain-fed agriculture - that represents 93% of cultivated areas and is the means of support of 70% of the active population - is highly vulnerable to precipitation variability. To better understand and anticipate climate impacts on agriculture, crop models - that estimate crop yield from climate information (e.g rainfall, temperature, insolation, humidity) - have been developed. These crop models are useful (i) in ex ante analysis to quantify the impact of different strategies implementation - crop management (e.g. choice of varieties, sowing date), crop insurance or medium-range weather forecast - on yields, (ii) for early warning systems and to (iii) assess future food security. Yet, the successful application of these models depends on the accuracy of their climatic drivers. In the sudano-sahelian zone , the quality of precipitation estimations is then a key factor to understand and anticipate climate impacts on agriculture via crop modelling and yield estimations. Different kinds of precipitation estimations can be used. Ground measurements have long-time series but an insufficient network density, a large proportion of missing values, delay in reporting time, and they have limited availability. An answer to these shortcomings may lie in the field of remote sensing that provides satellite-based precipitation estimations. However, satellite-based rainfall estimates (SRFE) are not a direct measurement but rather an estimation of precipitation. Used as an input for crop models, it determines the performance of the simulated yield, hence SRFE require validation. The SARRAH crop model is used to model three different varieties of pearl millet (HKP, MTDO, Souna3) in a square degree centred on 13.5°N and 2.5°E, in Niger. Eight satellite-based rainfall daily products (PERSIANN, CMORPH, TRMM 3b42-RT, GSMAP MKV+, GPCP, TRMM 3b42v6, RFEv2 and

  20. Accurate azimuth estimates from a large aperture hydrophone array using T-phase waveforms

    Science.gov (United States)

    Hanson, Jeffrey A.; Given, Holly K.

    A simple method is described whereby station-to-source azimuths are estimated by fitting a plane wave to envelope functions of T-phases observed on a 5-element hydrophone array around Ascension Island, South Atlantic Ocean. When applied to a data set of 55 earthquakes of known location ranging between 2 and 45 degrees distance from Ascension Island, estimated azimuths have a standard deviation of 3.3 degrees from reference azimuths when 3 or more hydrophone elements are used. The standard deviation decreases to 1.8 degrees if T-phase data from all 5 hydrophone elements are used. We also investigate variations in predicted errors for different array geometries and arrival azimuths. This simple method is amenable to automation and can easily be incorporated into a global monitoring system.

  1. Accurate group velocity estimation for unmanned aerial vehicle-based acoustic atmospheric tomography.

    Science.gov (United States)

    Rogers, Kevin J; Finn, Anthony

    2017-02-01

    Acoustic atmospheric tomography calculates temperature and wind velocity fields in a slice or volume of atmosphere based on travel time estimates between strategically located sources and receivers. The technique discussed in this paper uses the natural acoustic signature of an unmanned aerial vehicle as it overflies an array of microphones on the ground. The sound emitted by the aircraft is recorded on-board and by the ground microphones. The group velocities of the intersecting sound rays are then derived by comparing these measurements. Tomographic inversion is used to estimate the temperature and wind fields from the group velocity measurements. This paper describes a technique for deriving travel time (and hence group velocity) with an accuracy of 0.1% using these assets. This is shown to be sufficient to obtain highly plausible tomographic inversion results that correlate well with independent SODAR measurements.

  2. 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

  3. Optimization of Photospheric Electric Field Estimates for Accurate Retrieval of Total Magnetic Energy Injection

    Science.gov (United States)

    Lumme, E.; Pomoell, J.; Kilpua, E. K. J.

    2017-12-01

    Estimates of the photospheric magnetic, electric, and plasma velocity fields are essential for studying the dynamics of the solar atmosphere, for example through the derivative quantities of Poynting and relative helicity flux and using the fields to obtain the lower boundary condition for data-driven coronal simulations. In this paper we study the performance of a data processing and electric field inversion approach that requires only high-resolution and high-cadence line-of-sight or vector magnetograms, which we obtain from the Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamics Observatory (SDO). The approach does not require any photospheric velocity estimates, and the lacking velocity information is compensated for using ad hoc assumptions. We show that the free parameters of these assumptions can be optimized to reproduce the time evolution of the total magnetic energy injection through the photosphere in NOAA AR 11158, when compared to recent state-of-the-art estimates for this active region. However, we find that the relative magnetic helicity injection is reproduced poorly, reaching at best a modest underestimation. We also discuss the effect of some of the data processing details on the results, including the masking of the noise-dominated pixels and the tracking method of the active region, neither of which has received much attention in the literature so far. In most cases the effect of these details is small, but when the optimization of the free parameters of the ad hoc assumptions is considered, a consistent use of the noise mask is required. The results found in this paper imply that the data processing and electric field inversion approach that uses only the photospheric magnetic field information offers a flexible and straightforward way to obtain photospheric magnetic and electric field estimates suitable for practical applications such as coronal modeling studies.

  4. Accurate estimation of camera shot noise in the real-time

    Science.gov (United States)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Rodin, Vladislav G.; Starikov, Rostislav S.

    2017-10-01

    Nowadays digital cameras are essential parts of various technological processes and daily tasks. They are widely used in optics and photonics, astronomy, biology and other various fields of science and technology such as control systems and video-surveillance monitoring. One of the main information limitations of photo- and videocameras are noises of photosensor pixels. Camera's photosensor noise can be divided into random and pattern components. Temporal noise includes random noise component while spatial noise includes pattern noise component. Temporal noise can be divided into signal-dependent shot noise and signal-nondependent dark temporal noise. For measurement of camera noise characteristics, the most widely used methods are standards (for example, EMVA Standard 1288). It allows precise shot and dark temporal noise measurement but difficult in implementation and time-consuming. Earlier we proposed method for measurement of temporal noise of photo- and videocameras. It is based on the automatic segmentation of nonuniform targets (ASNT). Only two frames are sufficient for noise measurement with the modified method. In this paper, we registered frames and estimated shot and dark temporal noises of cameras consistently in the real-time. The modified ASNT method is used. Estimation was performed for the cameras: consumer photocamera Canon EOS 400D (CMOS, 10.1 MP, 12 bit ADC), scientific camera MegaPlus II ES11000 (CCD, 10.7 MP, 12 bit ADC), industrial camera PixeLink PL-B781F (CMOS, 6.6 MP, 10 bit ADC) and video-surveillance camera Watec LCL-902C (CCD, 0.47 MP, external 8 bit ADC). Experimental dependencies of temporal noise on signal value are in good agreement with fitted curves based on a Poisson distribution excluding areas near saturation. Time of registering and processing of frames used for temporal noise estimation was measured. Using standard computer, frames were registered and processed during a fraction of second to several seconds only. Also the

  5. Plant DNA barcodes can accurately estimate species richness in poorly known floras.

    Directory of Open Access Journals (Sweden)

    Craig Costion

    Full Text Available BACKGROUND: Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70% and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. METHODOLOGY/PRINCIPAL FINDINGS: Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. CONCLUSIONS/SIGNIFICANCE: We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

  6. Plant DNA barcodes can accurately estimate species richness in poorly known floras.

    Science.gov (United States)

    Costion, Craig; Ford, Andrew; Cross, Hugh; Crayn, Darren; Harrington, Mark; Lowe, Andrew

    2011-01-01

    Widespread uptake of DNA barcoding technology for vascular plants has been slow due to the relatively poor resolution of species discrimination (∼70%) and low sequencing and amplification success of one of the two official barcoding loci, matK. Studies to date have mostly focused on finding a solution to these intrinsic limitations of the markers, rather than posing questions that can maximize the utility of DNA barcodes for plants with the current technology. Here we test the ability of plant DNA barcodes using the two official barcoding loci, rbcLa and matK, plus an alternative barcoding locus, trnH-psbA, to estimate the species diversity of trees in a tropical rainforest plot. Species discrimination accuracy was similar to findings from previous studies but species richness estimation accuracy proved higher, up to 89%. All combinations which included the trnH-psbA locus performed better at both species discrimination and richness estimation than matK, which showed little enhanced species discriminatory power when concatenated with rbcLa. The utility of the trnH-psbA locus is limited however, by the occurrence of intraspecific variation observed in some angiosperm families to occur as an inversion that obscures the monophyly of species. We demonstrate for the first time, using a case study, the potential of plant DNA barcodes for the rapid estimation of species richness in taxonomically poorly known areas or cryptic populations revealing a powerful new tool for rapid biodiversity assessment. The combination of the rbcLa and trnH-psbA loci performed better for this purpose than any two-locus combination that included matK. We show that although DNA barcodes fail to discriminate all species of plants, new perspectives and methods on biodiversity value and quantification may overshadow some of these shortcomings by applying barcode data in new ways.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Structural brain change in Attention Deficit Hyperactivity Disorder identified by meta-analysis.

    Science.gov (United States)

    Ellison-Wright, Ian; Ellison-Wright, Zoë; Bullmore, Ed

    2008-06-30

    The authors sought to map gray matter changes in Attention Deficit Hyperactivity Disorder (ADHD) using a novel technique incorporating neuro-imaging and genetic meta-analysis methods. A systematic search was conducted for voxel-based structural magnetic resonance imaging studies of patients with ADHD (or with related disorders) in relation to comparison groups. The authors carried out meta-analyses of the co-ordinates of gray matter differences. For the meta-analyses they hybridised the standard method of Activation Likelihood Estimation (ALE) with the rank approach used in Genome Scan Meta-Analysis (GSMA). This system detects three-dimensional conjunctions of co-ordinates from multiple studies and permits the weighting of studies in relation to sample size. For gray matter decreases, there were 7 studies including a total of 114 patients with ADHD (or related disorders) and 143 comparison subjects. Meta-analysis of these studies identified a significant regional gray matter reduction in ADHD in the right putamen/globus pallidus region. Four studies reported gray matter increases in ADHD but no regional increase was identified by meta-analysis. In ADHD there is gray matter reduction in the right putamen/globus pallidus region. This may be an anatomical marker for dysfunction in frontostriatal circuits mediating cognitive control. Right putamen lesions have been specifically associated with ADHD symptoms after closed head injuries in children.

  13. Structural brain change in Attention Deficit Hyperactivity Disorder identified by meta-analysis

    Directory of Open Access Journals (Sweden)

    Ellison-Wright Zoë

    2008-06-01

    Full Text Available Abstract Background The authors sought to map gray matter changes in Attention Deficit Hyperactivity Disorder (ADHD using a novel technique incorporating neuro-imaging and genetic meta-analysis methods. Methods A systematic search was conducted for voxel-based structural magnetic resonance imaging studies of patients with ADHD (or with related disorders in relation to comparison groups. The authors carried out meta-analyses of the co-ordinates of gray matter differences. For the meta-analyses they hybridised the standard method of Activation Likelihood Estimation (ALE with the rank approach used in Genome Scan Meta-Analysis (GSMA. This system detects three-dimensional conjunctions of co-ordinates from multiple studies and permits the weighting of studies in relation to sample size. Results For gray matter decreases, there were 7 studies including a total of 114 patients with ADHD (or related disorders and 143 comparison subjects. Meta-analysis of these studies identified a significant regional gray matter reduction in ADHD in the right putamen/globus pallidus region. Four studies reported gray matter increases in ADHD but no regional increase was identified by meta-analysis. Conclusion In ADHD there is gray matter reduction in the right putamen/globus pallidus region. This may be an anatomical marker for dysfunction in frontostriatal circuits mediating cognitive control. Right putamen lesions have been specifically associated with ADHD symptoms after closed head injuries in children.

  14. Low circulating adiponectin levels in women with polycystic ovary syndrome: an updated meta-analysis.

    Science.gov (United States)

    Li, Shan; Huang, Xiamei; Zhong, Huizhi; Peng, Qiliu; Chen, Siyuan; Xie, Yantong; Qin, Xue; Qin, Aiping

    2014-05-01

    Adiponectin, as an important adipocytokine, plays a pivotal role in the regulation of insulin sensitivity and metabolism. It has been reported that circulating adiponectin levels were decreased in women with polycystic ovary syndrome (PCOS). However, the results remained inconsistent. In order to derive a more precise estimation of this relationship, a large meta-analysis was performed in this study. A comprehensive systematic electronic search was conducted in electronic databases PubMed, EMBASE, and Web of Science up to November 30, 2013. Pooled weighted mean differences (WMDs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association. A meta-analysis technique was used to study 38 trials involving 1,944 PCOS women and 1,654 healthy controls. Overall pooled adiponectin levels in women with PCOS were significantly reduced compared with healthy controls (WMD -2.67, 95% CI -3.22 to -2.13; P = 0.000), yet with significant heterogeneity across studies (I(2) = 95.9%, P = 0.000). In subgroup analysis by HOMA-IR ratio and total testosterone ratio, inconsistent results were presented. No single study was found to affect the overall results by sensitivity testing. Meta-regression suggested that BMI might contribute little to the heterogeneity between including studies. Cumulative meta-analysis demonstrated the reliability and stability of the meta-analysis results. No evidence of publication bias was observed. Our meta-analysis suggested that circulating adiponectin levels in women with PCOS were significantly lower than those in healthy controls, which indicated that circulating adiponectin might play a role in the development of PCOS.

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

    Science.gov (United States)

    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.

  16. The Remote Food Photography Method accurately estimates dry powdered foods—the source of calories for many infants

    Science.gov (United States)

    Duhé, Abby F.; Gilmore, L. Anne; Burton, Jeffrey H.; Martin, Corby K.; Redman, Leanne M.

    2016-01-01

    Background Infant formula is a major source of nutrition for infants with over half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water making it necessary to develop methods that can accurately estimate the amount of powder used prior to reconstitution. Objective To assess the use of the Remote Food Photography Method (RFPM) to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. Methods For each serving size (1-scoop, 2-scoop, 3-scoop, and 4-scoop), a set of seven test bottles and photographs were prepared including the recommended gram weight of powdered formula of the respective serving size by the manufacturer, three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended, and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard RFPM analysis procedures. The ratio estimates and the United States Department of Agriculture (USDA) data tables were used to generate food and nutrient information to provide the RFPM estimates. Statistical Analyses Performed Equivalence testing using the two one-sided t- test (TOST) approach was used to determine equivalence between the actual gram weights and the RFPM estimated weights for all samples, within each serving size, and within under-prepared and over-prepared bottles. Results For all bottles, the gram weights estimated by the RFPM were within 5% equivalence bounds with a slight under-estimation of 0.05 g (90% CI [−0.49, 0.40]; p<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. Conclusion The maximum observed mean error was an overestimation of 1.58% of powdered formula by the RFPM under

  17. Accurate estimation of airborne ultrasonic time-of-flight for overlapping echoes.

    Science.gov (United States)

    Sarabia, Esther G; Llata, Jose R; Robla, Sandra; Torre-Ferrero, Carlos; Oria, Juan P

    2013-11-12

    In this work, an analysis of the transmission of ultrasonic signals generated by piezoelectric sensors for air applications is presented. Based on this analysis, an ultrasonic response model is obtained for its application to the recognition of objects and structured environments for navigation by autonomous mobile robots. This model enables the analysis of the ultrasonic response that is generated using a pair of sensors in transmitter-receiver configuration using the pulse-echo technique. This is very interesting for recognizing surfaces that simultaneously generate a multiple echo response. This model takes into account the effect of the radiation pattern, the resonant frequency of the sensor, the number of cycles of the excitation pulse, the dynamics of the sensor and the attenuation with distance in the medium. This model has been developed, programmed and verified through a battery of experimental tests. Using this model a new procedure for obtaining accurate time of flight is proposed. This new method is compared with traditional ones, such as threshold or correlation, to highlight its advantages and drawbacks. Finally the advantages of this method are demonstrated for calculating multiple times of flight when the echo is formed by several overlapping echoes.

  18. 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.

  19. 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 ...

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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:…

  6. 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:.

  7. The Obesity Factor: How Cardiorespiratory Fitness is Estimated More Accurately in People with Obesity.

    Science.gov (United States)

    Königstein, Karsten; Klenk, Christopher; Rossmeissl, Anja; Baumann, Sandra; Infanger, Denis; Hafner, Benjamin; Hinrichs, Timo; Hanssen, Henner; Schmidt-Trucksäss, Arno

    2018-02-01

    Cardiopulmonary exercise testing is clinically used to estimate cardiorespiratory fitness (CRF). The relation to total body mass (TBM) leads to an underestimation of CRF in people with obesity and to inappropriate prognostic and therapeutic decisions. This study aimed to determine body composition-derived bias in the estimation of CRF in people with obesity. Two hundred eleven participants (58.8% women; mean BMI 35.7 kg/m 2 [± 6.94; 20.7-58.6]) were clinically examined, and body composition (InBody720; InBody Co., Ltd., Seoul, South Korea) and spiroergometrical peak oxygen consumption (VO 2 peak) were assessed. The impacts of TBM, lean body mass (LBM), and skeletal muscle mass (SMM) on CRF estimates were analyzed by the application of respective weight models. Linear regression and plotting of residuals against BMI were performed on the whole study population and two subgroups (BMI < 30 kg/m 2 and BMI ≥ 30 kg/m 2 ). For every weight model, Δmean VO 2 peak (expected - measured) was positive. LBM and SMM had a considerable impact on VO 2 peak demand (P = 0.001; ΔR 2  = 2.3%; adjusted R 2  = 56% and P = 0.001; ΔR 2 = 2.7%; adjusted R 2  = 56%), whereas TBM did not. Confounding of body composition on VO 2 peak did not differ in LBM and SMM. TBM-adjusted overestimation of relative VO 2 demand is much higher in people with obesity than in those without. LBM or SMM adjustment may be superior alternatives, although small residual body composition-derived bias remains. © 2017 The Obesity Society.

  8. Compact and accurate linear and nonlinear autoregressive moving average model parameter estimation using laguerre functions

    DEFF Research Database (Denmark)

    Chon, K H; Cohen, R J; Holstein-Rathlou, N H

    1997-01-01

    average models, as is the case for the Volterra-Wiener analysis, we propose an ARMA model-based approach. The proposed algorithm is essentially the same as LEK, but this algorithm is extended to include past values of the output as well. Thus, all of the advantages associated with using the Laguerre...... the physiological interpretation of higher order kernels easier. Furthermore, simulation results show better performance of the proposed approach in estimating the system dynamics than LEK in certain cases, and it remains effective in the presence of significant additive measurement noise....

  9. 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.

  10. Accurate estimate of the relic density and the kinetic decoupling in nonthermal dark matter models

    International Nuclear Information System (INIS)

    Arcadi, Giorgio; Ullio, Piero

    2011-01-01

    Nonthermal dark matter generation is an appealing alternative to the standard paradigm of thermal WIMP dark matter. We reconsider nonthermal production mechanisms in a systematic way, and develop a numerical code for accurate computations of the dark matter relic density. We discuss, in particular, scenarios with long-lived massive states decaying into dark matter particles, appearing naturally in several beyond the standard model theories, such as supergravity and superstring frameworks. Since nonthermal production favors dark matter candidates with large pair annihilation rates, we analyze the possible connection with the anomalies detected in the lepton cosmic-ray flux by Pamela and Fermi. Concentrating on supersymmetric models, we consider the effect of these nonstandard cosmologies in selecting a preferred mass scale for the lightest supersymmetric particle as a dark matter candidate, and the consequent impact on the interpretation of new physics discovered or excluded at the LHC. Finally, we examine a rather predictive model, the G2-MSSM, investigating some of the standard assumptions usually implemented in the solution of the Boltzmann equation for the dark matter component, including coannihilations. We question the hypothesis that kinetic equilibrium holds along the whole phase of dark matter generation, and the validity of the factorization usually implemented to rewrite the system of a coupled Boltzmann equation for each coannihilating species as a single equation for the sum of all the number densities. As a byproduct we develop here a formalism to compute the kinetic decoupling temperature in case of coannihilating particles, which can also be applied to other particle physics frameworks, and also to standard thermal relics within a standard cosmology.

  11. The Remote Food Photography Method Accurately Estimates Dry Powdered Foods-The Source of Calories for Many Infants.

    Science.gov (United States)

    Duhé, Abby F; Gilmore, L Anne; Burton, Jeffrey H; Martin, Corby K; Redman, Leanne M

    2016-07-01

    Infant formula is a major source of nutrition for infants, with more than half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water, making it necessary to develop methods that can accurately estimate the amount of powder used before reconstitution. Our aim was to assess the use of the Remote Food Photography Method to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. For each serving size (1 scoop, 2 scoops, 3 scoops, and 4 scoops), a set of seven test bottles and photographs were prepared as follow: recommended gram weight of powdered formula of the respective serving size by the manufacturer; three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended; and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard Remote Food Photography Method analysis procedures. The ratio estimates and the US Department of Agriculture data tables were used to generate food and nutrient information to provide the Remote Food Photography Method estimates. Equivalence testing using the two one-sided t tests approach was used to determine equivalence between the actual gram weights and the Remote Food Photography Method estimated weights for all samples, within each serving size, and within underprepared and overprepared bottles. For all bottles, the gram weights estimated by the Remote Food Photography Method were within 5% equivalence bounds with a slight underestimation of 0.05 g (90% CI -0.49 to 0.40; P<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. The maximum observed mean error was an overestimation of 1.58% of powdered formula by the Remote

  12. Cerebellar atrophy in neurodegeneration-a meta-analysis.

    Science.gov (United States)

    Gellersen, Helena M; Guo, Christine C; O'Callaghan, Claire; Tan, Rachel H; Sami, Saber; Hornberger, Michael

    2017-09-01

    The cerebellum has strong cortical and subcortical connectivity, but is rarely taken into account for clinical diagnosis in many neurodegenerative conditions, particularly in the absence of clinical ataxia. The current meta-analysis aims to assess patterns of cerebellar grey matter atrophy in seven neurodegenerative conditions (Alzheimer's disease (AD), Parkinson's disease (PD) and Huntington's disease (HD), frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), multiple system atrophy (MSA), progressive supranuclear palsy (MSP)). We carried out a systematic search in PubMed (any date: 14 July 2016) and a hand search of references from pertinent articles according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The authors were contacted to provide missing coordinate data. Peer-reviewed studies with direct comparison of patient and control groups, and availability of coordinate data of grey matter cerebellar atrophy in patients were included. These coordinates were used in an anatomical likelihood estimation meta-analysis. Across 54 studies, clusters of cerebellar atrophy were found for AD, ALS, FTD, MSA, and PSP. Atrophy patterns were largely disease-specific, with overlap in certain areas of the cerebellar hemisphere, which showed marked atrophy in AD, ALS, FTD and PSP (Crus I/II), and MSA and PSP (lobules I-IV), respectively. Atrophy colocated with cerebellar areas implicated for motor (PSP, MSA) or cognitive symptoms (FTD, ALS, PSP) in the diseases. Our findings suggest that cerebellar changes are largely disease-specific and correspond to cortical or subcortical changes in neurodegenerative conditions. High clinical variability in PD and HD samples may explain the absence of findings for consistent grey matter loss across studies. Our results have clinical implications for diagnosis and cerebellar neuroimaging referencing approaches. © Article author(s) (or their employer(s) unless otherwise stated

  13. Bisphosphonates and dental implants: A meta-analysis.

    Science.gov (United States)

    Chrcanovic, Bruno Ramos; Albrektsson, Tomas; Wennerberg, Ann

    2016-04-01

    To test the null hypothesis of no difference in the implant failure rates, marginal bone loss, and postoperative infection for patients receiving or not receiving bisphosphonates, against the alternative hypothesis of a difference. An electronic search was undertaken in October 2015 in PubMed/Medline, Web of Science, and Embase, plus hand-searching and databases of clinical trials. Eligibility criteria included clinical human studies, either randomized or not. A total of 18 publications were included in the review. Concerning implant failure, the meta-analysis found a risk ratio of 1.73 (95% confidence interval [CI] 1.21-2.48, P = .003) for patients taking bisphosphonates, when compared to patients not taking the medicament. The probability of an implant failure in patients taking bisphosphonates was estimated to be 1.5% (0.015, 95% CI 0.006- 0.023, standard error [SE] 0.004, P bisphosphonates may affect the marginal bone loss of dental implants, due to a limited number of studies reporting this outcome. Due to a lack of sufficient information, meta-analysis for the outcome "postoperative infection" was not performed. The results of the present study cannot suggest that the insertion of dental implants in patients taking BPs affects the implant failure rates, due to a limited number of published studies, all characterized by a low level of specificity, and most of them dealing with a limited number of cases without a proper control group. Therefore, the real effect of BPs on the osseointegration and survival of dental implants is still not well established.

  14. Voxel-based registration of simulated and real patient CBCT data for accurate dental implant pose estimation

    Science.gov (United States)

    Moreira, António H. J.; Queirós, Sandro; Morais, Pedro; Rodrigues, Nuno F.; Correia, André Ricardo; Fernandes, Valter; Pinho, A. C. M.; Fonseca, Jaime C.; Vilaça, João. L.

    2015-03-01

    The success of dental implant-supported prosthesis is directly linked to the accuracy obtained during implant's pose estimation (position and orientation). Although traditional impression techniques and recent digital acquisition methods are acceptably accurate, a simultaneously fast, accurate and operator-independent methodology is still lacking. Hereto, an image-based framework is proposed to estimate the patient-specific implant's pose using cone-beam computed tomography (CBCT) and prior knowledge of implanted model. The pose estimation is accomplished in a threestep approach: (1) a region-of-interest is extracted from the CBCT data using 2 operator-defined points at the implant's main axis; (2) a simulated CBCT volume of the known implanted model is generated through Feldkamp-Davis-Kress reconstruction and coarsely aligned to the defined axis; and (3) a voxel-based rigid registration is performed to optimally align both patient and simulated CBCT data, extracting the implant's pose from the optimal transformation. Three experiments were performed to evaluate the framework: (1) an in silico study using 48 implants distributed through 12 tridimensional synthetic mandibular models; (2) an in vitro study using an artificial mandible with 2 dental implants acquired with an i-CAT system; and (3) two clinical case studies. The results shown positional errors of 67+/-34μm and 108μm, and angular misfits of 0.15+/-0.08° and 1.4°, for experiment 1 and 2, respectively. Moreover, in experiment 3, visual assessment of clinical data results shown a coherent alignment of the reference implant. Overall, a novel image-based framework for implants' pose estimation from CBCT data was proposed, showing accurate results in agreement with dental prosthesis modelling requirements.

  15. Accurate motor mapping in awake common marmosets using micro-electrocorticographical stimulation and stochastic threshold estimation.

    Science.gov (United States)

    Kosugi, Akito; Takemi, Mitsuaki; Tia, Banty; Castagnola, Elisa; Ansaldo, Alberto; Sato, Kenta; Awiszus, Friedemann; Seki, Kazuhiko; Ricci, Davide; Fadiga, Luciano; Iriki, Atsushi; Ushiba, Junichi

    2018-03-01

    Motor map has been widely used as an indicator of motor skills and learning, cortical injury, plasticity, and functional recovery. Cortical stimulation mapping using epidural electrodes is recently adopted for animal studies. However, several technical limitations still remain. Test-retest reliability of epidural cortical stimulation (ECS) mapping has not been examined in detail. Many previous studies defined evoked movements and motor thresholds by visual inspection, and thus, lacked quantitative measurements. A reliable and quantitative motor map is important to elucidate the mechanisms of motor cortical reorganization. The objective of the current study was to perform reliable ECS mapping of motor representations based on the motor thresholds, which were stochastically estimated by motor evoked potentials and chronically implanted micro-electrocorticographical (μECoG) electrode arrays, in common marmosets. Approach. ECS was applied using the implanted μECoG electrode arrays in three adult common marmosets under awake conditions. Motor evoked potentials were recorded through electromyographical electrodes implanted in upper limb muscles. The motor threshold was calculated through a modified maximum likelihood threshold-hunting algorithm fitted with the recorded data from marmosets. Further, a computer simulation confirmed reliability of the algorithm. Main results. Computer simulation suggested that the modified maximum likelihood threshold-hunting algorithm enabled to estimate motor threshold with acceptable precision. In vivo ECS mapping showed high test-retest reliability with respect to the excitability and location of the cortical forelimb motor representations. Significance. Using implanted μECoG electrode arrays and a modified motor threshold-hunting algorithm, we were able to achieve reliable motor mapping in common marmosets with the ECS system. © 2018 IOP Publishing Ltd.

  16. Is 10-second electrocardiogram recording enough for accurately estimating heart rate in atrial fibrillation.

    Science.gov (United States)

    Shuai, Wei; Wang, Xi-Xing; Hong, Kui; Peng, Qiang; Li, Ju-Xiang; Li, Ping; Chen, Jing; Cheng, Xiao-Shu; Su, Hai

    2016-07-15

    At present, the estimation of rest heart rate (HR) in atrial fibrillation (AF) is obtained by apical auscultation for 1min or on the surface electrocardiogram (ECG) by multiplying the number of RR intervals on the 10second recording by six. But the reasonability of 10second ECG recording is controversial. ECG was continuously recorded at rest for 60s to calculate the real rest HR (HR60s). Meanwhile, the first 10s and 30s ECG recordings were used for calculating HR10s (sixfold) and HR30s (twofold). The differences of HR10s or HR30s with the HR60s were compared. The patients were divided into three sub-groups on the HR60s 100bpm. No significant difference among the mean HR10s, HR30s and HR60s was found. A positive correlation existed between HR10s and HR60s or HR30s and HR60s. Bland-Altman plot showed that the 95% reference limits were high as -11.0 to 16.0bpm for HR10s, but for HR30s these values were only -4.5 to 5.2bpm. Among the three subgroups with HR60s 100bpm, the 95% reference limits with HR60s were -8.9 to 10.6, -10.5 to 14.0 and -11.3 to 21.7bpm for HR10s, but these values were -3.9 to 4.3, -4.1 to 4.6 and -5.3 to 6.7bpm for HR30s. As 10s ECG recording could not provide clinically accepted estimation HR, ECG should be recorded at least for 30s in the patients with AF. It is better to record ECG for 60s when the HR is rapid. Copyright © 2016. Published by Elsevier Ireland Ltd.

  17. 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.

  18. How Acute Total Sleep Loss Affects the Attending Brain: A Meta-Analysis of Neuroimaging Studies

    Science.gov (United States)

    Ma, Ning; Dinges, David F.; Basner, Mathias; Rao, Hengyi

    2015-01-01

    Study Objectives: Attention is a cognitive domain that can be severely affected by sleep deprivation. Previous neuroimaging studies have used different attention paradigms and reported both increased and reduced brain activation after sleep deprivation. However, due to large variability in sleep deprivation protocols, task paradigms, experimental designs, characteristics of subject populations, and imaging techniques, there is no consensus regarding the effects of sleep loss on the attending brain. The aim of this meta-analysis was to identify brain activations that are commonly altered by acute total sleep deprivation across different attention tasks. Design: Coordinate-based meta-analysis of neuroimaging studies of performance on attention tasks during experimental sleep deprivation. Methods: The current version of the activation likelihood estimation (ALE) approach was used for meta-analysis. The authors searched published articles and identified 11 sleep deprivation neuroimaging studies using different attention tasks with a total of 185 participants, equaling 81 foci for ALE analysis. Results: The meta-analysis revealed significantly reduced brain activation in multiple regions following sleep deprivation compared to rested wakefulness, including bilateral intraparietal sulcus, bilateral insula, right prefrontal cortex, medial frontal cortex, and right parahippocampal gyrus. Increased activation was found only in bilateral thalamus after sleep deprivation compared to rested wakefulness. Conclusion: Acute total sleep deprivation decreases brain activation in the fronto-parietal attention network (prefrontal cortex and intraparietal sulcus) and in the salience network (insula and medial frontal cortex). Increased thalamic activation after sleep deprivation may reflect a complex interaction between the de-arousing effects of sleep loss and the arousing effects of task performance on thalamic activity. Citation: Ma N, Dinges DF, Basner M, Rao H. How acute total

  19. Análise de agrupamento para implementação da meta-análise em estimativas de herdabilidade para características de crescimento em bovinos de corte Cluster analysis for meta-analysis implementation for heritability of estimates growth traits in beef cattle

    Directory of Open Access Journals (Sweden)

    Juliana Di Giorgio Giannotti

    2005-08-01

    Full Text Available Estimativas de herdabilidade de características de crescimento são informações muito utilizadas em programas de melhoramento genético de bovinos de corte. Neste trabalho, foram compiladas 869 estimativas de herdabilidade, provenientes de 186 artigos publicados, das características peso ao nascimento, peso à desmama, peso aos 365 dias e peso aos 550 dias, de bovinos de corte de origem indiana. As estimativas foram divididas em grupos, em cada uma das quatro características, utilizando-se o método de agrupamento de Ward, e combinadas, dentro de cada grupo, por intermédio da meta-análise. Observou-se, para todas as características, que os grupos compostos por animais da raça Nelore presentes, em sua maioria, no Brasil, apresentaram maiores estimativas combinadas de herdabilidade que os demais grupos. Foram utilizados dois métodos, o da máxima verossimilhança restrita e o proposto por DerSimonian e Laird, para estimar a variância entre os estudos, tendo o primeiro apresentado valores superiores.Heritability estimates of growth traits are essential informations in animal breeding programs. In this paper, 869 heritability estimates of birth weight, weaning weight, weight at 365 days old and weight at 550 days old, of 186 reports were compiled. The estimates were divided in groups using the Ward method of cluster analysis, and pooled by meta-analysis. It was observed, for all traits, that groups from Nelore breed, majority in Brasil, showed greater pooled heritability estimates than the other groups. The methods, restricted maximum likelihood and DerSimonian and Laird, were used to estimate the variance between studies, where the first method showed higher variances.

  20. Merging glider and ocean color data to accurately estimate phytoplankton biomass in Oregon's coastal waters

    Science.gov (United States)

    McKibben, M.; Shearman, R. K.; Barth, J. A.; White, A. E.

    2016-02-01

    Long-term deployments of vertically-profiling platforms are becoming more common, providing a data-rich source of in situ ocean parameters ideal for pairing with satellite remote sensing data, particularly in areas with persistent cloud coverage. Regional development of methods that couple satellite and in situ data in ways that maximize the descriptive power of each is one of the crucial next steps in oceanographic research. For example, subsurface chlorophyll-a (chl-a) maxima often occur below the first optical depth (FOD), the maximum depth covered by satellite chl-a. In these cases, the sensors effectively miss a majority of phytoplankton biomass. Here we develop methods to merge 5 years of Slocum glider profiles and ocean color data in Oregon's coastal waters in order to quantify the occurrence of chl-a within the full euphotic zone and to improve biomass estimations in this region. This work includes two primary goals. First, the relative accuracy, precision, and uncertainty of the datasets are assessed, including comparison of vertical glider profiles of chl-a concentration, corrected to account for non-photochemical quenching, to satellite retrievals. Secondly, we have characterized the vertical distribution of chl-a and scattering and determined the seasonality and frequency of chl-a features below the FOD. We will discuss results of this study relative to physical and chemical forcing within the region.

  1. Early Start DENVER Model: A Meta - analysis

    Directory of Open Access Journals (Sweden)

    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”.

  2. 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

    Is there an association between regular exercise, defined as a structured program of increased physical activity at least 1 month in duration, and improvements in measures of executive functions compared with children who engage in their normal daily activities? The association between increased physical activity and changes in performance on tasks of executive functions have not been well elucidated in children. Executive functioning is important to intellectual development and academic success in children, and inexpensive, nonpharmacological methods for the treatment of executive dysfunction represent an attractive interventional target. To estimate the effect of a structured regular exercise program on neuropsychological domains of executive function in children ages 7 to 12. We performed a systematic review of English and non-English articles using Cochrane Library, EBSCO CINAHL, Ovid MEDLINE, PSYCInfo, Pubmed, and Web of Science, including all years allowed by each individual search engine. The search string used was "(exercise OR phys*) AND (cognit* OR executive) AND (child* OR preadolesc*)." The authors of the studies selected for review were contacted for any unpublished data. Randomized controlled trials, which enrolled children between the ages of 7 and 12, with randomization to either normal activity or a structured physical activity intervention consisting of scheduled aerobic exercise, at least once per week, for a period of at least 1 month. Eligible studies must have included a neuropsychological battery of tests that measured at least 1 executive function both before and after the intervention was completed. Two independent reviewers examined the screened studies in detail for potential inclusion. The results of the individual examinations were compared; if any discrepancies were present, a third party analyzed the study to determine if it should be included in the meta-analysis. A total of 18 studies were identified by abstract as candidates for

  3. Genital chlamydia prevalence in Europe and non-European high income countries: systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Shelagh M Redmond

    Full Text Available Accurate information about the prevalence of Chlamydia trachomatis is needed to assess national prevention and control measures.We systematically reviewed population-based cross-sectional studies that estimated chlamydia prevalence in European Union/European Economic Area (EU/EEA Member States and non-European high income countries from January 1990 to August 2012. We examined results in forest plots, explored heterogeneity using the I² statistic, and conducted random effects meta-analysis if appropriate. Meta-regression was used to examine the relationship between study characteristics and chlamydia prevalence estimates.We included 25 population-based studies from 11 EU/EEA countries and 14 studies from five other high income countries. Four EU/EEA Member States reported on nationally representative surveys of sexually experienced adults aged 18-26 years (response rates 52-71%. In women, chlamydia point prevalence estimates ranged from 3.0-5.3%; the pooled average of these estimates was 3.6% (95% CI 2.4, 4.8, I² 0%. In men, estimates ranged from 2.4-7.3% (pooled average 3.5%; 95% CI 1.9, 5.2, I² 27%. Estimates in EU/EEA Member States were statistically consistent with those in other high income countries (I² 0% for women, 6% for men. There was statistical evidence of an association between survey response rate and estimated chlamydia prevalence; estimates were higher in surveys with lower response rates, (p = 0.003 in women, 0.018 in men.Population-based surveys that estimate chlamydia prevalence are at risk of participation bias owing to low response rates. Estimates obtained in nationally representative samples of the general population of EU/EEA Member States are similar to estimates from other high income countries.

  4. Global Prevalence of Chronic Kidney Disease - A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Nathan R Hill

    Full Text Available Chronic kidney disease (CKD is a global health burden with a high economic cost to health systems and is an independent risk factor for cardiovascular disease (CVD. All stages of CKD are associated with increased risks of cardiovascular morbidity, premature mortality, and/or decreased quality of life. CKD is usually asymptomatic until later stages and accurate prevalence data are lacking. Thus we sought to determine the prevalence of CKD globally, by stage, geographical location, gender and age. A systematic review and meta-analysis of observational studies estimating CKD prevalence in general populations was conducted through literature searches in 8 databases. We assessed pooled data using a random effects model. Of 5,842 potential articles, 100 studies of diverse quality were included, comprising 6,908,440 patients. Global mean(95%CI CKD prevalence of 5 stages 13·4%(11·7-15·1%, and stages 3-5 was 10·6%(9·2-12·2%. Weighting by study quality did not affect prevalence estimates. CKD prevalence by stage was Stage-1 (eGFR>90+ACR>30: 3·5% (2·8-4·2%; Stage-2 (eGFR 60-89+ACR>30: 3·9% (2·7-5·3%; Stage-3 (eGFR 30-59: 7·6% (6·4-8·9%; Stage-4 = (eGFR 29-15: 0·4% (0·3-0·5%; and Stage-5 (eGFR<15: 0·1% (0·1-0·1%. CKD has a high global prevalence with a consistent estimated global CKD prevalence of between 11 to 13% with the majority stage 3. Future research should evaluate intervention strategies deliverable at scale to delay the progression of CKD and improve CVD outcomes.

  5. Estimating diabetes prevalence in South Auckland: how accurate is a method that combines lists of linked health datasets?

    Science.gov (United States)

    Thornley, Simon; Marshall, Roger; Jackson, Gary; Smith, James; Chan, Wing-Cheuk; Wright, Craig; Gentles, Dudley; Jackson, Rod

    2010-12-17

    To assess the accuracy of a method for estimating adult diabetes prevalence that combines linked, routine health datasets in South Auckland, New Zealand. We used a simple algorithm that combined records of laboratory testing, drug dispensing and hospital diagnoses applied to National Health Index-linked health data in South Auckland to estimate the prevalence of diabetes in 2007. We investigated the sensitivity of this 'combined list' algorithm against a gold standard of individuals with diagnosed diabetes enrolled in a Chronic Care Management programme (CCMP). We also assessed the sensitivity of this algorithm against an estimated diabetes population generated using capture-recapture methods. From the combined-list algorithm, 25,797 (7.2%) South Aucklanders aged 15 years and over had diabetes. During this period, 10,725 patients were enrolled in the CCMP. The combined list algorithm correctly identified (sensitivity) 10,351/10,725 (96.5%) of those enrolled. When we used the capture-recapture estimated diabetes population as an alternative gold standard, 34,418 [9.5%] of South Aucklanders 15 years and over had diabetes, with the sensitivity of the combined list method falling to about 75% (25,797/34,418). Linked health data provide reasonably accurate estimates of diabetes prevalence in a New Zealand population; particularly for cases with longstanding or complicated disease.

  6. Prevalence of asthenopia in children: a systematic review with meta-analysis

    OpenAIRE

    Vilela, Manuel A.P.; Pellanda, Lucia C.; Fassa, Anaclaudia G.; Castagno, Victor D.

    2015-01-01

    OBJECTIVE: To estimate the prevalence of asthenopia in 0-18 year-old children through a systematic review and meta-analysis of prevalence studies.SOURCES: Inclusion criteria were population-based studies from 1960 to May of 2014 reporting the prevalence of asthenopia in children. The search was performed independently by two reviewers in the PubMed, EMBASE, and LILACS databases, with no language restriction. This systematic review was performed in accordance with the Cochrane Collaboration gu...

  7. A statistical method was used for the meta-analysis of tests for latent TB in the absence of a gold standard, combining random-effect and latent-class methods to estimate test accuracy.

    Science.gov (United States)

    Sadatsafavi, Mohsen; Shahidi, Neal; Marra, Fawziah; FitzGerald, Mark J; Elwood, Kevin R; Guo, Na; Marra, Carlo A

    2010-03-01

    Because of the lack of a gold standard, the diagnostic performance of tests for the detection of latent tuberculosis infection (LTBI) is not known. However, statistical methods can be used to estimate the accuracy from the studies reporting the concordance among the tests. We developed a random-effect latent-class model to estimate performance characteristics of three LTBI diagnostic tests: tuberculin skin test (TST, at 10-mm cutoff), QuantiFERON-TB gold (QFG), and TSPOT-TB from the studies evaluating agreement among the tests. Nineteen studies were included. QFG had a sensitivity of 0.642 (95% confidence interval [CI]: 0.593-0.691) and specificity of 0.996 (95% CI: 0.989-1.000), TSPOT-TB had a sensitivity of 0.500 (95% CI: 0.334-0.666) and specificity of 0.906 (95% CI: 0.882-0.929), and TST had a sensitivity of 0.709 (95% CI: 0.658-0.761) and specificity of 0.683 (95% CI: 0.522-0.844). Results were not sensitive to the inclusion of any single study. When only the three studies that reported on TSPOT were removed, estimates for the other two tests varied minimally. Statistical methods can help estimate the accuracy of LTBI tests. Although the specificities were close to their reported values in the literature, the estimates for sensitivities were low; a finding that should be carefully evaluated.

  8. Estimating patient dose from CT exams that use automatic exposure control: Development and validation of methods to accurately estimate tube current values.

    Science.gov (United States)

    McMillan, Kyle; Bostani, Maryam; Cagnon, Christopher H; Yu, Lifeng; Leng, Shuai; McCollough, Cynthia H; McNitt-Gray, Michael F

    2017-08-01

    The vast majority of body CT exams are performed with automatic exposure control (AEC), which adapts the mean tube current to the patient size and modulates the tube current either angularly, longitudinally or both. However, most radiation dose estimation tools are based on fixed tube current scans. Accurate estimates of patient dose from AEC scans require knowledge of the tube current values, which is usually unavailable. The purpose of this work was to develop and validate methods to accurately estimate the tube current values prescribed by one manufacturer's AEC system to enable accurate estimates of patient dose. Methods were developed that took into account available patient attenuation information, user selected image quality reference parameters and x-ray system limits to estimate tube current values for patient scans. Methods consistent with AAPM Report 220 were developed that used patient attenuation data that were: (a) supplied by the manufacturer in the CT localizer radiograph and (b) based on a simulated CT localizer radiograph derived from image data. For comparison, actual tube current values were extracted from the projection data of each patient. Validation of each approach was based on data collected from 40 pediatric and adult patients who received clinically indicated chest (n = 20) and abdomen/pelvis (n = 20) scans on a 64 slice multidetector row CT (Sensation 64, Siemens Healthcare, Forchheim, Germany). For each patient dataset, the following were collected with Institutional Review Board (IRB) approval: (a) projection data containing actual tube current values at each projection view, (b) CT localizer radiograph (topogram) and (c) reconstructed image data. Tube current values were estimated based on the actual topogram (actual-topo) as well as the simulated topogram based on image data (sim-topo). Each of these was compared to the actual tube current values from the patient scan. In addition, to assess the accuracy of each method in estimating

  9. Association of LPP and TAGAP Polymorphisms with Celiac Disease Risk: A Meta-Analysis

    Directory of Open Access Journals (Sweden)

    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.

  10. Leukocyte telomere length and hippocampus volume: a meta-analysis [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Gustav Nilsonne

    2015-10-01

    Full Text Available Leukocyte telomere length has been shown to correlate to hippocampus volume, but effect estimates differ in magnitude and are not uniformly positive. This study aimed primarily to investigate the relationship between leukocyte telomere length and hippocampus gray matter volume by meta-analysis and secondarily to investigate possible effect moderators. Five studies were included with a total of 2107 participants, of which 1960 were contributed by one single influential study. A random-effects meta-analysis estimated the effect to r = 0.12 [95% CI -0.13, 0.37] in the presence of heterogeneity and a subjectively estimated moderate to high risk of bias. There was no evidence that apolipoprotein E (APOE genotype was an effect moderator, nor that the ratio of leukocyte telomerase activity to telomere length was a better predictor than leukocyte telomere length for hippocampus volume. This meta-analysis, while not proving a positive relationship, also is not able to disprove the earlier finding of a positive correlation in the one large study included in analyses. We propose that a relationship between leukocyte telomere length and hippocamus volume may be mediated by transmigrating monocytes which differentiate into microglia in the brain parenchyma.

  11. How Does Physical Activity Intervention Improve Self-Esteem and Self-Concept in Children and Adolescents? Evidence from a Meta-Analysis

    OpenAIRE

    Liu, Mingli; Wu, Lang; Ming, Qingsen

    2015-01-01

    Objective To perform a systematic review and meta-analysis for the effects of physical activity intervention on self-esteem and self-concept in children and adolescents, and to identify moderator variables by meta-regression. Design A meta-analysis and meta-regression. Method Relevant studies were identified through a comprehensive search of electronic databases. Study inclusion criteria were: (1) intervention should be supervised physical activity, (2) reported sufficient data to estimate po...

  12. Natural funnel asymmetries. A simulation analysis of the three basic tools of meta analysis

    DEFF Research Database (Denmark)

    Callot, Laurent Abdelkader Francois; Paldam, Martin

    Meta-analysis studies a set of estimates of one parameter with three basic tools: The funnel diagram is the distribution of the estimates as a function of their precision; the funnel asymmetry test, FAT; and the meta average, where PET is an estimate. The FAT-PET MRA is a meta regression analysis......, on the data of the funnel, which jointly estimates the FAT and the PET. Ideal funnels are lean and symmetric. Empirical funnels are wide, and most have asymmetries biasing the plain average. Many asymmetries are due to censoring made during the research-publication process. The PET is tooled to correct...

  13. Exposure to radiation therapy is associated with female reproductive health among childhood cancer survivors: a meta-analysis study.

    Science.gov (United States)

    Gao, Wei; Liang, Jin-Xiao; Yan, Qiu

    2015-08-01

    Many epidemiological studies have revealed a positive correlation between medical radiation exposure and the reproductive health in female childhood cancer survivors. However, because of variations in the samples size, such studies showed partly inconsistent conclusions. The aim of this meta-analysis was to clarify the association between radiotherapy and the risk of reproductive health impairment for female who survived from childhood cancer. Fourteen cohort studies involving childhood radiotherapy were selected as the exposure of interest and the impaired reproductive health condition during the childbearing age as the outcome. Among meta-analysis of observational studies found in Pubmed and Embase from 1900 to 2014, we evaluated those relevant observational studies which surveyed the association of medical radiation and reproductive health in female childhood cancer survivors. Review Manager 5.2 and STATA 12.0 software were used to perform the meta-analysis. Study-specific estimations for each outcome were combined into a pooled relative risk (RR) with 95% confidence interval (CI) by a meta-analytic approach. Based on a random-effects meta-analysis, significant association between infertility (RR = 1.28, 95% CI = 1.16-1.42), acute ovarian failure (AOF) (RR = 9.51, 95% CI = 5.03-17.96), low level of anti mullerian hormone (AMH) (childhood cancer survivors' reproductive capability and pregnancy outcomes. Although there were some limitations, our meta-analysis further supported that radiotherapy was a risk factor for reproductive health problems of female who survived from childhood cancer.

  14. Heteroscedastic ridge regression approaches for genome-wide prediction with a focus on computational efficiency and accurate effect estimation.

    Science.gov (United States)

    Hofheinz, Nina; Frisch, Matthias

    2014-03-20

    Ridge regression with heteroscedastic marker variances provides an alternative to Bayesian genome-wide prediction methods. Our objectives were to suggest new methods to determine marker-specific shrinkage factors for heteroscedastic ridge regression and to investigate their properties with respect to computational efficiency and accuracy of estimated effects. We analyzed published data sets of maize, wheat, and sugar beet as well as simulated data with the new methods. Ridge regression with shrinkage factors that were proportional to single-marker analysis of variance estimates of variance components (i.e., RRWA) was the fastest method. It required computation times of less than 1 sec for medium-sized data sets, which have dimensions that are common in plant breeding. A modification of the expectation-maximization algorithm that yields heteroscedastic marker variances (i.e., RMLV) resulted in the most accurate marker effect estimates. It outperformed the homoscedastic ridge regression approach for best linear unbiased prediction in particular for situations with high marker density and strong linkage disequilibrium along the chromosomes, a situation that occurs often in plant breeding populations. We conclude that the RRWA and RMLV approaches provide alternatives to the commonly used Bayesian methods, in particular for applications in which computational feasibility or accuracy of effect estimates are important, such as detection or functional analysis of genes or planning crosses.

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

    Science.gov (United States)

    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

  16. Meta-analysis of the association between short-term exposure to ambient ozone and respiratory hospital admissions

    International Nuclear Information System (INIS)

    Ji Meng; Bell, Michelle L; Cohan, Daniel S

    2011-01-01

    Ozone is associated with health impacts including respiratory outcomes; however, results differ across studies. Meta-analysis is an increasingly important approach to synthesizing evidence across studies. We conducted meta-analysis of short-term ozone exposure and respiratory hospitalizations to evaluate variation across studies and explore some of the challenges in meta-analysis. We identified 136 estimates from 96 studies and investigated how estimates differed by age, ozone metric, season, lag, region, disease category, and hospitalization type. Overall results indicate associations between ozone and various kinds of respiratory hospitalizations; however, study characteristics affected risk estimates. Estimates were similar, but higher, for the elderly compared to all ages and for previous day exposure compared to same day exposure. Comparison across studies was hindered by variation in definitions of disease categories, as some (e.g., asthma) were identified through ≥ 3 different sets of ICD codes. Although not all analyses exhibited evidence of publication bias, adjustment for publication bias generally lowered overall estimates. Emergency hospitalizations for total respiratory disease increased by 4.47% (95% interval: 2.48, 6.50%) per 10 ppb 24 h ozone among the elderly without adjustment for publication bias and 2.97% (1.05, 4.94%) with adjustment. Comparison of multi-city study results and meta-analysis based on single-city studies further suggested publication bias.

  17. 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)

  18. Detecting deception in children: A meta-analysis.

    Science.gov (United States)

    Gongola, Jennifer; Scurich, Nicholas; Quas, Jodi A

    2017-02-01

    Although research reveals that children as young as 3 can use deception and will take steps to obscure truth, research concerning how well others detect children's deceptive efforts remains unclear. Yet adults regularly assess whether children are telling the truth in a variety of contexts, including at school, in the home, and in legal settings, particularly in investigations of maltreatment. We conducted a meta-analysis to synthesize extant research concerning adults' ability to detect deceptive statements produced by children. We included 45 experiments involving 7,893 adult judges and 1,858 children. Overall, adults could accurately discriminate truths/lies at an average rate of 54%, which is slightly but significantly above chance levels. The average rate at which true statements were correctly classified as honest was higher (63.8%), whereas the rate at which lies were classified as dishonest was not different from chance (47.5%). A small positive correlation emerged between judgment confidence and judgment accuracy. Professionals (e.g., social workers, police officers, teachers) slightly outperformed laypersons (e.g., college undergraduates). Finally, exploratory analyses revealed that the child's age did not significantly affect the rate at which adults could discriminate truths/lies from chance. Future research aimed toward improving lie detection accuracy might focus more on individual differences in children's lie-telling abilities in order to uncover any reliable indicators of deception. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  19. 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.

  20. 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

  1. Incentives Increase Participation in Mass Dog Rabies Vaccination Clinics and Methods of Coverage Estimation Are Assessed to Be Accurate

    Science.gov (United States)

    Steinmetz, Melissa; Czupryna, Anna; Bigambo, Machunde; Mzimbiri, Imam; Powell, George; Gwakisa, Paul

    2015-01-01

    In this study we show that incentives (dog collars and owner wristbands) are effective at increasing owner participation in mass dog rabies vaccination clinics and we conclude that household questionnaire surveys and the mark-re-sight (transect survey) method for estimating post-vaccination coverage are accurate when all dogs, including puppies, are included. Incentives were distributed during central-point rabies vaccination clinics in northern Tanzania to quantify their effect on owner participation. In villages where incentives were handed out participation increased, with an average of 34 more dogs being vaccinated. Through economies of scale, this represents a reduction in the cost-per-dog of $0.47. This represents the price-threshold under which the cost of the incentive used must fall to be economically viable. Additionally, vaccination coverage levels were determined in ten villages through the gold-standard village-wide census technique, as well as through two cheaper and quicker methods (randomized household questionnaire and the transect survey). Cost data were also collected. Both non-gold standard methods were found to be accurate when puppies were included in the calculations, although the transect survey and the household questionnaire survey over- and under-estimated the coverage respectively. Given that additional demographic data can be collected through the household questionnaire survey, and that its estimate of coverage is more conservative, we recommend this method. Despite the use of incentives the average vaccination coverage was below the 70% threshold for eliminating rabies. We discuss the reasons and suggest solutions to improve coverage. Given recent international targets to eliminate rabies, this study provides valuable and timely data to help improve mass dog vaccination programs in Africa and elsewhere. PMID:26633821

  2. Incentives Increase Participation in Mass Dog Rabies Vaccination Clinics and Methods of Coverage Estimation Are Assessed to Be Accurate.

    Science.gov (United States)

    Minyoo, Abel B; Steinmetz, Melissa; Czupryna, Anna; Bigambo, Machunde; Mzimbiri, Imam; Powell, George; Gwakisa, Paul; Lankester, Felix

    2015-12-01

    In this study we show that incentives (dog collars and owner wristbands) are effective at increasing owner participation in mass dog rabies vaccination clinics and we conclude that household questionnaire surveys and the mark-re-sight (transect survey) method for estimating post-vaccination coverage are accurate when all dogs, including puppies, are included. Incentives were distributed during central-point rabies vaccination clinics in northern Tanzania to quantify their effect on owner participation. In villages where incentives were handed out participation increased, with an average of 34 more dogs being vaccinated. Through economies of scale, this represents a reduction in the cost-per-dog of $0.47. This represents the price-threshold under which the cost of the incentive used must fall to be economically viable. Additionally, vaccination coverage levels were determined in ten villages through the gold-standard village-wide census technique, as well as through two cheaper and quicker methods (randomized household questionnaire and the transect survey). Cost data were also collected. Both non-gold standard methods were found to be accurate when puppies were included in the calculations, although the transect survey and the household questionnaire survey over- and under-estimated the coverage respectively. Given that additional demographic data can be collected through the household questionnaire survey, and that its estimate of coverage is more conservative, we recommend this method. Despite the use of incentives the average vaccination coverage was below the 70% threshold for eliminating rabies. We discuss the reasons and suggest solutions to improve coverage. Given recent international targets to eliminate rabies, this study provides valuable and timely data to help improve mass dog vaccination programs in Africa and elsewhere.

  3. Incentives Increase Participation in Mass Dog Rabies Vaccination Clinics and Methods of Coverage Estimation Are Assessed to Be Accurate.

    Directory of Open Access Journals (Sweden)

    Abel B Minyoo

    2015-12-01

    Full Text Available In this study we show that incentives (dog collars and owner wristbands are effective at increasing owner participation in mass dog rabies vaccination clinics and we conclude that household questionnaire surveys and the mark-re-sight (transect survey method for estimating post-vaccination coverage are accurate when all dogs, including puppies, are included. Incentives were distributed during central-point rabies vaccination clinics in northern Tanzania to quantify their effect on owner participation. In villages where incentives were handed out participation increased, with an average of 34 more dogs being vaccinated. Through economies of scale, this represents a reduction in the cost-per-dog of $0.47. This represents the price-threshold under which the cost of the incentive used must fall to be economically viable. Additionally, vaccination coverage levels were determined in ten villages through the gold-standard village-wide census technique, as well as through two cheaper and quicker methods (randomized household questionnaire and the transect survey. Cost data were also collected. Both non-gold standard methods were found to be accurate when puppies were included in the calculations, although the transect survey and the household questionnaire survey over- and under-estimated the coverage respectively. Given that additional demographic data can be collected through the household questionnaire survey, and that its estimate of coverage is more conservative, we recommend this method. Despite the use of incentives the average vaccination coverage was below the 70% threshold for eliminating rabies. We discuss the reasons and suggest solutions to improve coverage. Given recent international targets to eliminate rabies, this study provides valuable and timely data to help improve mass dog vaccination programs in Africa and elsewhere.

  4. An Accurate Computational Tool for Performance Estimation of FSO Communication Links over Weak to Strong Atmospheric Turbulent Channels

    Directory of Open Access Journals (Sweden)

    Theodore D. Katsilieris

    2017-03-01

    Full Text Available The terrestrial optical wireless communication links have attracted significant research and commercial worldwide interest over the last few years due to the fact that they offer very high and secure data rate transmission with relatively low installation and operational costs, and without need of licensing. However, since the propagation path of the information signal, i.e., the laser beam, is the atmosphere, their effectivity affects the atmospheric conditions strongly in the specific area. Thus, system performance depends significantly on the rain, the fog, the hail, the atmospheric turbulence, etc. Due to the influence of these effects, it is necessary to study, theoretically and numerically, very carefully before the installation of such a communication system. In this work, we present exactly and accurately approximate mathematical expressions for the estimation of the average capacity and the outage probability performance metrics, as functions of the link’s parameters, the transmitted power, the attenuation due to the fog, the ambient noise and the atmospheric turbulence phenomenon. The latter causes the scintillation effect, which results in random and fast fluctuations of the irradiance at the receiver’s end. These fluctuations can be studied accurately with statistical methods. Thus, in this work, we use either the lognormal or the gamma–gamma distribution for weak or moderate to strong turbulence conditions, respectively. Moreover, using the derived mathematical expressions, we design, accomplish and present a computational tool for the estimation of these systems’ performances, while also taking into account the parameter of the link and the atmospheric conditions. Furthermore, in order to increase the accuracy of the presented tool, for the cases where the obtained analytical mathematical expressions are complex, the performance results are verified with the numerical estimation of the appropriate integrals. Finally, using

  5. Prevalence of attention deficit/hyperactivity disorder among children and adolescents in China: a systematic review and meta-analysis.

    Science.gov (United States)

    Wang, Tingting; Liu, Kaihua; Li, Zhanzhan; Xu, Yang; Liu, Yuan; Shi, Wenpei; Chen, Lizhang

    2017-01-19

    Attention deficit/hyperactivity disorder (ADHD), the most common childhood neurobehavioural disorder, can produce a series of negative effects on children, adolescents, and even adults as well as place a serious economic burden on families and society. However, the prevalence of ADHD is not well understood in China. The goal of this study was to estimate the pooled prevalence of ADHD among children and adolescents in China using a systematic review and meta-analysis. A systematic literature search was conducted in PubMed, Web of Science, MEDLINE, CNKI, Wanfang, Weipu and CBM databases, and relevant articles published from inception to March 1, 2016, that provided the prevalence of ADHD among children and adolescents in China were reviewed. The risk of bias in individual studies was assessed using the Risk of Bias Tool for prevalence studies. Pooled-prevalence estimates were calculated with a random-effects model. Sources of heterogeneity were explored using subgroup analyses. Sixty-seven studies with a total of 275,502 individuals were included in this study. The overall pooled-prevalence of ADHD among children and adolescents in China was 6.26% (95% CI: 5.36-7.22%) with significant heterogeneity (I 2  = 99.0%, P China is generally consistent with the worldwide prevalence and shows that ADHD affects quite a large number of people under 18 years old. However, a nationwide study is needed to provide more accurate estimations.

  6. Diagnostic performance of computed tomography angiography in peripheral arterial injury due to trauma: a systematic review and meta-analysis.

    Science.gov (United States)

    Jens, S; Kerstens, M K; Legemate, D A; Reekers, J A; Bipat, S; Koelemay, M J W

    2013-09-01

    To evaluate the diagnostic accuracy of computed tomography angiography (CTA) in detecting arterial lesions in patients with suspected arterial injury of the upper or lower extremity due to trauma. A systematic review and meta-analysis was carried out. Medline and Embase were searched on August 13, 2012, for studies comparing CTA with surgery, digital subtraction angiography (DSA), or follow-up, which allowed extraction of data into two-by-two tables. The methodological quality of included studies was assessed using the QUADAS tool. Summary estimates of sensitivity and specificity of CTA in identifying or excluding arterial lesions were obtained using a bivariate model. This review included 11 studies making up a total of 891 trauma patients. The included studies were of moderate methodological quality and at risk of misclassification and verification bias. Some 4.2% of all CTA studies were non-diagnostic. The summary estimates of sensitivity and specificity of CTA were 96.2% (95% CI 93.5-97.8%) and 99.2% (95% CI 96.8-99.8%), respectively. Despite methodological flaws, the excellent estimates of sensitivity and specificity indicate that CTA is an accurate modality for evaluating arterial lesions in patients with extremity trauma and can replace DSA. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. Clinical Effectiveness of Occupational Therapy in Mental Health: A Meta-Analysis.

    Science.gov (United States)

    Ikiugu, Moses N; Nissen, Ranelle M; Bellar, Cali; Maassen, Alexya; Van Peursem, Katlin

    The purpose of this study was to estimate the effectiveness of theory-based occupational therapy interventions in improving occupational performance and well-being among people with a mental health diagnosis. The meta-analysis included 11 randomized controlled trials with a total of 520 adult participants with a mental health diagnosis. Outcomes were occupational performance, well-being, or both. We conducted meta-analyses using Comprehensive Meta-Analysis software (Version 3.0) with occupational performance and well-being as the dependent variables. Results indicated a medium effect of intervention on improving occupational performance (mean Hedge's g = 0.50, Z = 4.05, p occupational therapy interventions may be effective in improving occupational performance and well-being among people with a mental health diagnosis and should be an integral part of rehabilitation services in mental health. Copyright © 2017 by the American Occupational Therapy Association, Inc.

  12. The association of Raynaud syndrome with β-blockers: a meta-analysis.

    Science.gov (United States)

    Mohokum, Melvin; Hartmann, Peter; Schlattmann, Peter

    2012-10-01

    Vasospastic disorders of the digital circulation such as the Raynaud syndrome (RS) are known side effects of treatment of β-adrenergic blockade. The prevalence of RS in patients during treatment with β-blockers is not well defined. The objective of this meta-analysis is to assess the prevalence of RS in patients receiving β-blockers. A literature search was performed for studies dealing with RS and patients receiving β-blockers. The studies provided sufficient data to estimate the prevalence of RS in patients receiving β-blockers. A total of 13 eligible studies, contributing data on 1012 individuals, were included in this meta-analysis. For RS in patients receiving β-blockers, a pooled prevalence of 14.7% (95% confidence interval 0.076-0.236) were obtained. Statistically publication bias was not present (P = .877). Despite some heterogeneity, there is a possible indication of an association between RS and patients receiving β-blockers.

  13. Systematic Review and Meta-Analysis of Neuropsychiatric Symptoms and Executive Functioning in Adults With Phenylketonuria

    Science.gov (United States)

    Bilder, Deborah A.; Noel, J. Kay; Baker, Erin R.; Irish, William; Chen, Yinpu; Merilainen, Markus J.; Prasad, Suyash; Winslow, Barbara J.

    2016-01-01

    ABSTRACT This systematic review and meta-analysis (MA) investigates the impact of elevated blood phenylalanine (Phe) on neuropsychiatric symptoms in adults with phenylketonuria (PKU). The meta-analysis of PKU is challenging because high-quality evidence is lacking due to the limited number of affected individuals and few placebo-controlled, double-blind studies of adults with high and low blood Phe. Neuropsychiatric symptoms associated with PKU exceed general population estimates for inattention, hyperactivity, depression, and anxiety. High Phe is associated with an increased prevalence of neuropsychiatric symptoms and executive functioning deficits whereas low Phe is associated with improved neurological performance. Findings support lifelong maintenance of low blood Phe. PMID:27805419

  14. The association of Raynaud syndrome with thromboangiitis obliterans--a meta-analysis.

    Science.gov (United States)

    Hartmann, Peter; Mohokum, Melvin; Schlattmann, Peter

    2012-05-01

    Thromboangiitis obliterans (TAO) has traditionally been included among the diseases associated with Raynaud syndrome (RS). The prevalence of RS in patients with TAO is not well defined. The objective of this meta-analysis is to assess the prevalence of RS in patients with TAO. A literature search was performed for the studies dealing with RS and TAO. The studies provided sufficient data to estimate the prevalence of RS in patients with TAO. A total of 8 eligible studies, contributing data on 851 patients, were included in this meta-analysis. For TAO, a pooled prevalence of 28.1% and 95% confidence interval ([CI] = 0.158, 0.423) were obtained. Statistically publication bias was not present (P = .232). Despite some heterogeneity, there is a possible indication of an association between RS and patients with TAO.

  15. [Development of an Excel spreadsheet for meta-analysis of indirect and mixed treatment comparisons].

    Science.gov (United States)

    Tobías, Aurelio; Catalá-López, Ferrán; Roqué, Marta

    2014-01-01

    Meta-analyses in clinical research usually aimed to evaluate treatment efficacy and safety in direct comparison with a unique comparator. Indirect comparisons, using the Bucher's method, can summarize primary data when information from direct comparisons is limited or nonexistent. Mixed comparisons allow combining estimates from direct and indirect comparisons, increasing statistical power. There is a need for simple applications for meta-analysis of indirect and mixed comparisons. These can easily be conducted using a Microsoft Office Excel spreadsheet. We developed a spreadsheet for indirect and mixed effects comparisons of friendly use for clinical researchers interested in systematic reviews, but non-familiarized with the use of more advanced statistical packages. The use of the proposed Excel spreadsheet for indirect and mixed comparisons can be of great use in clinical epidemiology to extend the knowledge provided by traditional meta-analysis when evidence from direct comparisons is limited or nonexistent.

  16. Using the Autism-Spectrum Quotient to Measure Autistic Traits in Anorexia Nervosa: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Westwood, Heather; Eisler, Ivan; Mandy, William; Leppanen, Jenni; Treasure, Janet; Tchanturia, Kate

    2016-01-01

    Interest in the link between Autism Spectrum Disorder (ASD) and Anorexia Nervosa (AN) has led to estimates of the prevalence of autistic traits in AN. This systematic review and meta-analysis assessed the use of the Autism-Spectrum Quotient (AQ) or abbreviated version (AQ-10) to examine whether patients with AN have elevated levels of autistic…

  17. A Meta-Analysis of Adolescent Psychosocial Smoking Prevention Programs Published between 1978 and 1997 in the United States

    Science.gov (United States)

    Hwang, Myunghee Song; Yeagley, Kathleen Lux; Petosa, Rick

    2004-01-01

    Psychosocial smoking prevention studies have shown inconsistent results and theory-driven programs have been related to program success. This meta-analysis was used as a judgment tool for resolving these issues by estimating average program effects and investigating the relative efficacy of program types. The present study examined 65 adolescent…

  18. Anxiety Disorders in Williams Syndrome Contrasted with Intellectual Disability and the General Population: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Royston, R.; Howlin, P.; Waite, J.; Oliver, C.

    2017-01-01

    Individuals with specific genetic syndromes associated with intellectual disability (ID), such as Williams syndrome (WS), are at increased risk for developing anxiety disorders. A systematic literature review identified sixteen WS papers that could generate pooled prevalence estimates of anxiety disorders for WS. A meta-analysis compared these…

  19. Impact of Persistent Antiphospholipid Antibodies on Risk of Incident Symptomatic Thromboembolism in Children : A Systematic Review and Meta-Analysis

    NARCIS (Netherlands)

    Kenet, Gili; Aronis, Sofia; Berkun, Yackov; Bonduel, Mariana; Chan, Anthony; Goldenberg, Neil A.; Holzhauer, Susanne; Iorio, Alfonso; Journeycake, Janna; Junker, Ralf; Male, Christoph; Manco-Johnson, Marilyn; Massicotte, Patti; Mesters, Rolf; Monagle, Paul; van Ommen, Heleen; Rafini, Leslie; Simioni, Paolo; Young, Guy; Nowak-Goettl, Ulrike

    2011-01-01

    The aim of this study was to estimate the impact of antiphospholipid (aPL) antibodies on the risk of incident thromboembolism (TE; arterial and venous) in children via meta-analysis of published observational studies. A systematic search of electronic databases (Medline, EMBASE, OVID, Web of

  20. The obsessive compulsive spectrum in schizophrenia, a meta-analysis and meta-regression exploring prevalence rates

    NARCIS (Netherlands)

    Swets, Marije; Dekker, Jack; van Emmerik-van Oortmerssen, Katelijne; Smid, Geert E.; Smit, Filip; de Haan, Lieuwe; Schoevers, Robert A.

    2014-01-01

    The aims of this study were to conduct a meta-analysis and meta-regression to estimate the prevalence rates for obsessive compulsive symptoms (OCS) and obsessive compulsive disorder (OCD) in schizophrenia, and to investigate what influences these prevalence rates. Studies were identified via an

  1. Risk of postpartum relapse in bipolar disorder and postpartum psychosis : A systematic review and meta-analysis

    NARCIS (Netherlands)

    Wesseloo, R.; Kamperman, A.M.; Munk-Olsen, T.; Pop, V.J.M.; Kushner, S.A.; Bergink, V.

    2016-01-01

    Objective: Women with a history of bipolar disorder, postpartum psychosis, or both are at high risk for postpartum relapse. The aim of this meta-analysis was to estimate the risk of postpartum relapse in these three patient groups. Method: A systematic literature search was conducted in all public

  2. 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.

  3. Exposure to organochlorine pollutants and type 2 diabetes: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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. 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...

  10. SU-D-BRA-01: Accurate Real-Time Tumor Motion Estimation from Respiratory Surrogates via Memory-Based Learning.

    Science.gov (United States)

    Li, R; Xing, L

    2012-06-01

    Respiratory tumor motion is a major challenge in radiation therapy. Effective beam gating or tracking approaches necessitate an accurate knowledge of the real-time tumor motion. Fluoroscopic tracking with implanted fiducial markers is invasive and exposes the patient to additional imaging dose. Respiratory surrogate signal measured by external noninvasive and non-ionizing devices provides an attractive approach, in which estimating the tumor motion from respiratory surrogates is crucial. We utilize a powerful memory-based learning approach to find the complex relations between tumor motion and respiratory surrogates. The learning method uses locally weighted functions to interpolate between and extrapolate from training data. Due to the local nature of the learning functions, it is inherently robust to outliers. Moreover, both training and adapting to new data is highly efficient and almost free, making it suitable for dynamically following possibly variable internal/external relations. We evaluated the method using respiratory motion data (3D tumor motion plus 1D surrogate) from six patients (three lung and three pancreas patients). Given only 5-sec (roughly one breath) pretreatment training data, the method achieved an average 3D error of 0.37 mm (range: 0.10 mm - 1.06 mm) and 95th percentile error of 0.86 mm (range: 0.24 mm - 2.47 mm) on 120-sec unseen test data. These errors are well below the average peak- to-peak amplitude (-10 mm). The errors decrease monotonically with an increasing amount of training data. Compared with the best linear model, the learning approach achieved a 21% reduction in error for an average patient (range: 10% - 42%). The memory-based learning technique is able to accurately capture the highly nonlinear and complex relations between tumor and surrogate motion in an efficient manner (∼1 ms per prediction). These desirable properties make it an ideal candidate for accurate and robust tumor gating/tracking using respiratory surrogates

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

    Science.gov (United States)

    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.

  12. 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.

  13. 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/

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

    Directory of Open Access Journals (Sweden)

    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.

  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. An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system.

    Science.gov (United States)

    Krause, Douglas J; Hinke, Jefferson T; Perryman, Wayne L; Goebel, Michael E; LeRoi, Donald J

    2017-01-01

    Measurements of body size and mass are fundamental to pinniped population management and research. Manual measurements tend to be accurate but are invasive and logistically challenging to obtain. Ground-based photogrammetric techniques are less invasive, but inherent limitations make them impractical for many field applications. The recent proliferation of unmanned aerial systems (UAS) in wildlife monitoring has provided a promising new platform for the photogrammetry of free-ranging pinnipeds. Leopard seals (Hydrurga leptonyx) are an apex predator in coastal Antarctica whose body condition could be a valuable indicator of ecosystem health. We aerially surveyed leopard seals of known body size and mass to test the precision and accuracy of photogrammetry from a small UAS. Flights were conducted in January and February of 2013 and 2014 and 50 photogrammetric samples were obtained from 15 unrestrained seals. UAS-derived measurements of standard length were accurate to within 2.01 ± 1.06%, and paired comparisons with ground measurements were statistically indistinguishable. An allometric linear mixed effects model predicted leopard seal mass within 19.40 kg (4.4% error for a 440 kg seal). Photogrammetric measurements from a single, vertical image obtained using UAS provide a noninvasive approach for estimating the mass and body condition of pinnipeds that may be widely applicable.

  17. An accurate and adaptable photogrammetric approach for estimating the mass and body condition of pinnipeds using an unmanned aerial system.

    Directory of Open Access Journals (Sweden)

    Douglas J Krause

    Full Text Available Measurements of body size and mass are fundamental to pinniped population management and research. Manual measurements tend to be accurate but are invasive and logistically challenging to obtain. Ground-based photogrammetric techniques are less invasive, but inherent limitations make them impractical for many field applications. The recent proliferation of unmanned aerial systems (UAS in wildlife monitoring has provided a promising new platform for the photogrammetry of free-ranging pinnipeds. Leopard seals (Hydrurga leptonyx are an apex predator in coastal Antarctica whose body condition could be a valuable indicator of ecosystem health. We aerially surveyed leopard seals of known body size and mass to test the precision and accuracy of photogrammetry from a small UAS. Flights were conducted in January and February of 2013 and 2014 and 50 photogrammetric samples were obtained from 15 unrestrained seals. UAS-derived measurements of standard length were accurate to within 2.01 ± 1.06%, and paired comparisons with ground measurements were statistically indistinguishable. An allometric linear mixed effects model predicted leopard seal mass within 19.40 kg (4.4% error for a 440 kg seal. Photogrammetric measurements from a single, vertical image obtained using UAS provide a noninvasive approach for estimating the mass and body condition of pinnipeds that may be widely applicable.

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

    Directory of Open Access Journals (Sweden)

    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

  19. 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.

  20. 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.

  1. Fast and accurate phylogenetic reconstruction from high-resolution whole-genome data and a novel robustness estimator.

    Science.gov (United States)

    Lin, Y; Rajan, V; Moret, B M E

    2011-09-01

    The rapid accumulation of whole-genome data has renewed interest in the study of genomic rearrangements. Comparative genomics, evolutionary biology, and cancer research all require models and algorithms to elucidate the mechanisms, history, and consequences of these rearrangements. However, even simple models lead to NP-hard problems, particularly in the area of phylogenetic analysis. Current approaches are limited to small collections of genomes and low-resolution data (typically a few hundred syntenic blocks). Moreover, whereas phylogenetic analyses from sequence data are deemed incomplete unless bootstrapping scores (a measure of confidence) are given for each tree edge, no equivalent to bootstrapping exists for rearrangement-based phylogenetic analysis. We describe a fast and accurate algorithm for rearrangement analysis that scales up, in both time and accuracy, to modern high-resolution genomic data. We also describe a novel approach to estimate the robustness of results-an equivalent to the bootstrapping analysis used in sequence-based phylogenetic reconstruction. We present the results of extensive testing on both simulated and real data showing that our algorithm returns very accurate results, while scaling linearly with the size of the genomes and cubically with their number. We also present extensive experimental results showing that our approach to robustness testing provides excellent estimates of confidence, which, moreover, can be tuned to trade off thresholds between false positives and false negatives. Together, these two novel approaches enable us to attack heretofore intractable problems, such as phylogenetic inference for high-resolution vertebrate genomes, as we demonstrate on a set of six vertebrate genomes with 8,380 syntenic blocks. A copy of the software is available on demand.

  2. Finger counting method is more accurate than age-based weight estimation formulae in estimating the weight of Hong Kong children presenting to the emergency department.

    Science.gov (United States)

    So, Jerome Lt; Chow, Eric Pf; Cattermole, Giles N; Graham, Colin A; Rainer, Timothy H

    2016-12-01

    The aim of the present study was to evaluate the finger counting method and compare its performance with four commonly used age-based weight estimation formulae in children aged 1-9 years presenting to the ED in Hong Kong. A cross-sectional, observational study of children aged 1-9 years who presented to the ED of a tertiary referral hospital in Hong Kong over a 6 month period was conducted. Actual weight was compared with estimated weight using the finger counting method and four commonly used age-based weight estimation formulae. Bland-Altman analysis was performed to evaluate the degree of agreement in which the mean percentage difference (MPD) and 95% limits of agreement (LOA) were calculated. Root mean squared error (RMSE) and proportions of weight estimates within 10%, 15% and 20% of actual weight were determined. A total of 4178 children were included. The finger counting method was the most accurate method (MPD 0.1%; 95% LOA -34.0% to 34.2%). The original Advanced Paediatric Life Support (APLS) formula (MPD -7.0%; 95% LOA -38.4% to 24.3%) and the updated APLS formula (MPD -0.4%; 95% LOA -38.5% to 37.8%) underestimated weight whereas the Luscombe formula (MPD 7.2%; 95% LOA -31.8% to 46.2%) and the Best Guess formula (MPD 10.6%; 95% LOA -27.3% to 48.4%) overestimated weight. The finger counting method had smallest RMSE of 4.06 kg and estimated the largest proportion of children within 10%, 15% and 20% of actual weight. The finger counting method outperforms the commonly used age-based weight estimation formulae in children aged 1-9 years presenting to the ED in Hong Kong. © 2016 Australasian College for Emergency Medicine and Australasian Society for Emergency Medicine.

  3. Systematic review and meta-analysis of method comparison studies of Masimo pulse co-oximeters (Radical-7™ or Pronto-7™) and HemoCue® absorption spectrometers (B-Hemoglobin or 201+) with laboratory haemoglobin estimation.

    Science.gov (United States)

    Hiscock, R; Kumar, D; Simmons, S W

    2015-05-01

    We assessed agreement in haemoglobin measurement between Masimo pulse co-oximeters (Rad-7™ and Pronto-7™) and HemoCue® photometers (201+ or B-Hemoglobin) with laboratory-based determination and identified 39 relevant studies (2915 patients in Masimo group and 3084 patients in HemoCue group). In the Masimo group, the overall mean difference was -0.03 g/dl (95% prediction interval -0.30 to 0.23) and 95% limits of agreement -3.0 to 2.9 g/dl compared to 0.08 g/dl (95% prediction interval -0.04 to 0.20) and 95% limits of agreement -1.3 to 1.4 g/dl in the HemoCue group. Only B-Hemoglobin exhibited bias (0.53, 95% prediction interval 0.27 to 0.78). The overall standard deviation of difference was larger (1.42 g/dl versus 0.64 g/dl) for Masimo pulse co-oximeters compared to HemoCue photometers. Masimo devices and HemoCue 201+ both provide an unbiased, pooled estimate of laboratory haemoglobin. However, Masimo devices have lower precision and wider 95% limits of agreement than HemoCue devices. Clinicians should carefully consider these limits of agreement before basing transfusion or other clinical decisions on these point-of-care measurements alone.

  4. Simplifying ART cohort monitoring: Can pharmacy stocks provide accurate estimates of patients retained on antiretroviral therapy in Malawi?

    Directory of Open Access Journals (Sweden)

    Tweya Hannock

    2012-07-01

    Full Text Available Abstract Background Routine monitoring of patients on antiretroviral therapy (ART is crucial for measuring program success and accurate drug forecasting. However, compiling data from patient registers to measure retention in ART is labour-intensive. To address this challenge, we conducted a pilot study in Malawi to assess whether patient ART retention could be determined using pharmacy records as compared to estimates of retention based on standardized paper- or electronic based cohort reports. Methods Twelve ART facilities were included in the study: six used paper-based registers and six used electronic data systems. One ART facility implemented an electronic data system in quarter three and was included as a paper-based system facility in quarter two only. Routine patient retention cohort reports, paper or electronic, were collected from facilities for both quarter two [April–June] and quarter three [July–September], 2010. Pharmacy stock data were also collected from the 12 ART facilities over the same period. Numbers of ART continuation bottles recorded on pharmacy stock cards at the beginning and end of each quarter were documented. These pharmacy data were used to calculate the total bottles dispensed to patients in each quarter with intent to estimate the number of patients retained on ART. Information for time required to determine ART retention was gathered through interviews with clinicians tasked with compiling the data. Results Among ART clinics with paper-based systems, three of six facilities in quarter two and four of five facilities in quarter three had similar numbers of patients retained on ART comparing cohort reports to pharmacy stock records. In ART clinics with electronic systems, five of six facilities in quarter two and five of seven facilities in quarter three had similar numbers of patients retained on ART when comparing retention numbers from electronically generated cohort reports to pharmacy stock records. Among

  5. Can endocranial volume be estimated accurately from external skull measurements in great-tailed grackles (Quiscalus mexicanus?

    Directory of Open Access Journals (Sweden)

    Corina J. Logan

    2015-06-01

    Full Text Available There is an increasing need to validate and collect data approximating brain size on individuals in the field to understand what evolutionary factors drive brain size variation within and across species. We investigated whether we could accurately estimate endocranial volume (a proxy for brain size, as measured by computerized tomography (CT scans, using external skull measurements and/or by filling skulls with beads and pouring them out into a graduated cylinder for male and female great-tailed grackles. We found that while females had higher correlations than males, estimations of endocranial volume from external skull measurements or beads did not tightly correlate with CT volumes. We found no accuracy in the ability of external skull measures to predict CT volumes because the prediction intervals for most data points overlapped extensively. We conclude that we are unable to detect individual differences in endocranial volume using external skull measurements. These results emphasize the importance of validating and explicitly quantifying the predictive accuracy of brain size proxies for each species and each sex.

  6. Efficacy of Auricular Acupressure for Chronic Low Back Pain: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

    Directory of Open Access Journals (Sweden)

    Li-Hua Yang

    2017-01-01

    Full Text Available Objectives. To identify the efficacy of auricular acupressure on pain and disability for chronic LBP by systematic review. Methods. A search of randomized controlled trials was conducted in four English medical electronic databases and three Chinese databases. Two reviewers independently retrieved related studies, assessed the methodological quality, and extracted data with a standardized data form. Meta-analyses were performed using all time-points meta-analysis. Results. A total of 7 trials met the inclusion criteria, of which 4 had the low risk of bias. The findings of this study showed that, for the immediate effect, auricular acupressure had large, significant effects in improving pain within 12 weeks. As for the follow-up effect, the pooled estimates also showed promising effect at 4-week follow-up after 4-week intervention (standardized mean difference = −1.13, 95% CI (-1.70, -0.56, P<0.001. But, for the disability level, the therapeutic effect was not significant (mean difference = −1.99, 95% CI (-4.93, 0.95, P=0.18. No serious adverse effects were recorded. Conclusions. The encouraging evidence of this study indicates that it is recommended to provide auricular acupressure to patients with chronic low back pain. However, a more accurate estimate of the effect will require further rigorously designed large-scale RCTs on chronic LBP for improving pain and disability.

  7. Characterization of Movement Disorder Phenomenology in Genetically Proven, Familial Frontotemporal Lobar Degeneration: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Gasca-Salas, Carmen; Masellis, Mario; Khoo, Edwin; Shah, Binit B; Fisman, David; Lang, Anthony E; Kleiner-Fisman, Galit

    2016-01-01

    Mutations in granulin (PGRN) and tau (MAPT), and hexanucleotide repeat expansions near the C9orf72 genes are the most prevalent genetic causes of frontotemporal lobar degeneration. Although behavior, language and movement presentations are common, the relationship between genetic subgroup and movement disorder phenomenology is unclear. We conducted a systematic review and meta-analysis of the literature characterizing the spectrum and prevalence of movement disorders in genetic frontotemporal lobar degeneration. Electronic databases were searched using terms related to frontotemporal lobar degeneration and movement disorders. Articles were included when cases had a proven genetic cause. Study-specific prevalence estimates for clinical features were transformed using Freeman-Tukey arcsine transformation, allowing for pooled estimates of prevalence to be generated using random-effects models. The mean age at onset was earlier in those with MAPT mutations compared to PGRN (pphenomenology in genetic frontotemporal lobar degeneration. Standardized prospective collection of clinical information in conjunction with genetic characterization will be crucial for accurate clinico-genetic correlation.

  8. Effects of Air Pollution on the Risk of Congenital Anomalies: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Esther Kai-Chieh Chen

    2014-07-01

    Full Text Available Congenital anomalies are the main causes of preterm and neonatal mortality and morbidity. We investigated the association between congenital anomalies and mothers’ exposure to air pollution during pregnancy by combining risk estimates for a variety of air pollutants (SO2, NO2, PM10, PM2.5, CO and O3 and anomaly defect outcomes. Seventeen articles were included in the systematic review and thirteen studies were taken into account in the meta-analysis. Combined estimated were calculated separately according to whether the exposure metric was continuous or categorical. Only one significant combination was; NO2 concentrations were significantly associated with coarctation of the aorta (OR = 1.20 per 10 ppb, 95% CI, (1.02, 1.41. This finding could stem from strong heterogeneity in study designs. Improved exposure assessment methods, in particular more accurate spatial measurements or modeling, standardized definition of cases and of better control of confounders are highly recommended for future congenital anomalies research in this area.

  9. Response Inhibition and Internet Gaming Disorder: A Meta-analysis.

    Science.gov (United States)

    Argyriou, Evangelia; Davison, Christopher B; Lee, Tayla T C

    2017-08-01

    Previous research has demonstrated that Internet Gaming Disorder (IGD) has multiple negative effects in psychological functioning and health. This makes the identification of its underpinnings, such as response inhibition, essential for the development of relevant interventions that target these core features of the disorder resulting in more effective treatment. Several empirical studies have evaluated the relationship between response inhibition deficits and IGD using neurocognitive tasks, but provided mixed results. In this study, we conducted a meta-analysis of studies using three neurocognitive tasks, the Go/No Go, the Stroop, and the Stop-Signal tasks, to integrate existing research and estimate the magnitude of this relationship. We found a medium overall effect size (d=0.56, 95% CI [0.32, 0.80]) indicating that compared with healthy individuals, individuals with IGD are more likely to exhibit impaired response inhibition. This finding is in alignment with literature on inhibition and addictive and impulsive behaviors, as well as with neuroimaging research. Theoretical implications regarding the conceptualization of IGD as a clinical disorder, shared commonalities with externalizing psychopathology, and clinical implications for treatment are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Prevalence of Sleepwalking: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Helen M Stallman

    Full Text Available Sleepwalking is thought to be a common arousal disorder; however, the epidemiology of this disorder has not yet been systematically examined. A systematic search of MEDLINE, CINAHL, EMBASE, PsycINFO, PubMed, and ScienceDirect was conducted for 'sleepwalking' OR 'somnambulism' in any field, to identify studies that reported the epidemiology of sleepwalking or sleepwalking disorders. Fifty-one studies assessed the prevalence rates of sleepwalking in a total sample of 100 490. The meta-analysis showed the estimated lifetime prevalence of sleepwalking was 6.9% (95% CI 4.6%-10.3%. The current prevalence rate of sleepwalking-within the last 12 months-was significantly higher in children 5.0% (95% CI 3.8%-6.5% than adults 1.5% (95% CI 1.0%-2.3%. There was no evidence of developmental trends in sleepwalking across childhood. The significant risk of bias across all studies suggests these results should be used cautiously. Further epidemiological research that addresses methodological problems found in studies of sleepwalking to date is needed.

  11. Prevalence of Sleepwalking: A Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Stallman, Helen M; Kohler, Mark

    2016-01-01

    Sleepwalking is thought to be a common arousal disorder; however, the epidemiology of this disorder has not yet been systematically examined. A systematic search of MEDLINE, CINAHL, EMBASE, PsycINFO, PubMed, and ScienceDirect was conducted for 'sleepwalking' OR 'somnambulism' in any field, to identify studies that reported the epidemiology of sleepwalking or sleepwalking disorders. Fifty-one studies assessed the prevalence rates of sleepwalking in a total sample of 100 490. The meta-analysis showed the estimated lifetime prevalence of sleepwalking was 6.9% (95% CI 4.6%-10.3%). The current prevalence rate of sleepwalking-within the last 12 months-was significantly higher in children 5.0% (95% CI 3.8%-6.5%) than adults 1.5% (95% CI 1.0%-2.3%). There was no evidence of developmental trends in sleepwalking across childhood. The significant risk of bias across all studies suggests these results should be used cautiously. Further epidemiological research that addresses methodological problems found in studies of sleepwalking to date is needed.

  12. 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.

  13. Ultrasound for the Diagnosis of Biliary Atresia: A Meta-Analysis.

    Science.gov (United States)

    Zhou, Luyao; Shan, Quanyuan; Tian, Wenshuo; Wang, Zhu; Liang, Jinyu; Xie, Xiaoyan

    2016-05-01

    The purpose of this meta-analysis was to summarize the evidence on the accuracy of various ultrasound findings for excluding a diagnosis of biliary atresia. We searched MEDLINE and the Web of Science databases for the period from January 1990 to May 2015. To be included, studies had to satisfy two criteria. First, the data needed to include 2 × 2 contingency data on the diagnostic accuracy of ultrasound in identifying biliary atresia in at least 10 patients with and 10 patients without disease. Second, the study needed to use surgery or biopsy for biliary atresia and surgery, biopsy, clinical follow-up, or some combination of the three as the reference standard for the exclusion of biliary atresia. The methodologic quality of each study was assessed with version 2 of the Quality Assessment of Diagnostic Accuracy Studies tool. Estimated sensitivity and specificity of each ultrasound characteristic were calculated using a random-effects model. Twenty-three studies published during 1998-2015 were included. Summary sensitivity and specificity were 0.85 (95% CI, 0.76-0.91) and 0.92 (95% CI, 0.81-0.97), respectively, for gallbladder abnormalities in 19 studies; 0.74 (95% CI, 0.61-0.84) and 0.97 (95% CI, 0.95-0.99), respectively, for triangular cord sign in 20 studies; and 0.95 (95% CI, 0.70-0.99) and 0.89 (95% CI, 0.79-0.94), respectively, for the combination of the triangular cord sign and gallbladder abnormalities in five studies. Subgroup analysis of an absent gallbladder in 10 studies yielded a summary specificity of 0.99 (95% CI, 0.93-1.00). The triangular cord sign and gallbladder abnormalities are the two most accurate and widely accepted ultrasound characteristics for diagnosing or excluding biliary atresia. Other ultrasound characteristics are less valuable for diagnosis or exclusion of biliary atresia.

  14. The efficacy of empathy training: A meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Teding van Berkhout, Emily; van Berkhout, Emily Teding; Malouff, John M

    2016-01-01

    [Correction Notice: An Erratum for this article was reported in Vol 63(1) of Journal of Counseling Psychology (see record 2015-58774-003). In the article, the last name of author Emily Teding van Berkhout was incorrectly set in the running head as van Berkhout. It should be Teding van Berkhout. All versions of this article have been corrected.] High levels of empathy are associated with healthy relationships and prosocial behavior; in health professionals, high levels of empathy are associated with better therapeutic outcomes. To determine whether empathy can be taught, researchers have evaluated empathy training programs. After excluding 1 outlier study that showed a very large effect with few participants, the meta-analysis included 18 randomized controlled trials of empathy training with a total of 1,018 participants. The findings suggest that empathy training programs are effective overall, with a medium effect (g = 0.63), adjusted to 0.51 after trim-and-fill evaluation for estimated publication bias. Moderator analyses indicated that 4 factors were statistically significantly associated with higher effect sizes: (a) training health professionals and university students rather than other types of individuals, (b) compensating trainees for their participation, (c) using empathy measures that focus exclusively on assessing understanding the emotions of others, feeling those emotions, or commenting accurately on the emotions, and (d) using objective measures rather than self-report measures. Number of hours of training and time between preintervention assessment and postintervention assessment were not statistically significantly associated with effect size, with 6 months the longest time period for assessment. The findings indicate that (a) empathy training tends to be effective and (b) experimental research is warranted on the impact of different types of trainees, training conditions, and types of assessment. (PsycINFO Database Record (c) 2016 APA, all rights

  15. Diaphragm and Lung Ultrasound to Predict Weaning Outcome: Systematic Review and Meta-Analysis.

    Science.gov (United States)

    Llamas-Álvarez, Ana M; Tenza-Lozano, Eva M; Latour-Pérez, Jaime

    2017-12-01

    Deciding the optimal timing for extubation in patients who are mechanically ventilated can be challenging, and traditional weaning predictor tools are not very accurate. The aim of this systematic review and meta-analysis was to assess the accuracy of lung and diaphragm ultrasound for predicting weaning outcomes in critically ill adults. MEDLINE, the Cochrane Library, Web of Science, Scopus, LILACS, Teseo, Tesis Doctorales en Red, and OpenGrey were searched, and the bibliographies of relevant studies were reviewed. Two researchers independently selected studies that met the inclusion criteria and assessed study quality in accordance with the Quality Assessment of Diagnostic Accuracy Studies-2 tool. The summary receiver-operating characteristic curve and pooled diagnostic OR (DOR) were estimated by using a bivariate random effects analysis. Sources of heterogeneity were explored by using predefined subgroup analyses and bivariate meta-regression. Nineteen studies involving 1,071 people were included in the study. For diaphragm thickening fraction, the area under the summary receiver-operating characteristic curve was 0.87, and DOR was 21 (95% CI, 11-40). Regarding diaphragmatic excursion, pooled sensitivity was 75% (95% CI, 65-85); pooled specificity, 75% (95% CI, 60-85); and DOR, 10 (95% CI, 4-24). For lung ultrasound, the area under the summary receiver-operating characteristic curve was 0.77, and DOR was 38 (95% CI, 7-198). Based on bivariate meta-regression analysis, a significantly higher specificity for diaphragm thickening fraction and higher sensitivity for diaphragmatic excursion was detected in studies with applicability concerns. Lung and diaphragm ultrasound can help predict weaning outcome, but its accuracy may vary depending on the patient subpopulation. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  16. Mixture models reveal multiple positional bias types in RNA-Seq data and lead to accurate transcript concentration estimates.

    Directory of Open Access Journals (Sweden)

    Andreas Tuerk

    2017-05-01

    Full Text Available Accuracy of transcript quantification with RNA-Seq is negatively affected by positional fragment bias. This article introduces Mix2 (rd. "mixquare", a transcript quantification method which uses a mixture of probability distributions to model and thereby neutralize the effects of positional fragment bias. The parameters of Mix2 are trained by Expectation Maximization resulting in simultaneous transcript abundance and bias estimates. We compare Mix2 to Cufflinks, RSEM, eXpress and PennSeq; state-of-the-art quantification methods implementing some form of bias correction. On four synthetic biases we show that the accuracy of Mix2 overall exceeds the accuracy of the other methods and that its bias estimates converge to the correct solution. We further evaluate Mix2 on real RNA-Seq data from the Microarray and Sequencing Quality Control (MAQC, SEQC Consortia. On MAQC data, Mix2 achieves improved correlation to qPCR measurements with a relative increase in R2 between 4% and 50%. Mix2 also yields repeatable concentration estimates across technical replicates with a relative increase in R2 between 8% and 47% and reduced standard deviation across the full concentration range. We further observe more accurate detection of differential expression with a relative increase in true positives between 74% and 378% for 5% false positives. In addition, Mix2 reveals 5 dominant biases in MAQC data deviating from the common assumption of a uniform fragment distribution. On SEQC data, Mix2 yields higher consistency between measured and predicted concentration ratios. A relative error of 20% or less is obtained for 51% of transcripts by Mix2, 40% of transcripts by Cufflinks and RSEM and 30% by eXpress. Titration order consistency is correct for 47% of transcripts for Mix2, 41% for Cufflinks and RSEM and 34% for eXpress. We, further, observe improved repeatability across laboratory sites with a relative increase in R2 between 8% and 44% and reduced standard deviation.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. Meta-analysis of perceived stress and its association with incident coronary heart disease.

    Science.gov (United States)

    Richardson, Safiya; Shaffer, Jonathan A; Falzon, Louise; Krupka, David; Davidson, Karina W; Edmondson, Donald

    2012-12-15

    Most studies examining potential associations between psychological factors and cardiovascular outcomes have focused on depression or anxiety. The effect of perceived stress on incident coronary heart disease (CHD) has yet to be reviewed systematically. We conducted a systematic review and meta-analysis of the association between perceived stress and incident CHD. Ovid, MEDLINE, and PsycINFO were searched as data sources. Prospective observational cohort studies were selected that measured self-reported perceived stress and assessed incident CHD at ≥6 months. We extracted study characteristics and estimates of the risk of incident CHD associated with high perceived stress versus low perceived stress. We identified 23 potentially relevant articles, of which 6 met our criteria (n = 118,696). Included studies measured perceived stress with validated measurements and nonvalidated simple self-report surveys. Incident CHD was defined as new diagnosis of, hospitalization for, or mortality secondary to CHD. Meta-analysis yielded an aggregate risk ratio of 1.27 (95% confidence interval 1.12 to 1.45) for the magnitude of the relation between high perceived stress and incident CHD. In conclusion, this meta-analysis suggests that high perceived stress is associated with a moderately increased risk of incident CHD. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. High versus low radioiodine activity in patients with differentiated thyroid cancer - A meta-analysis

    International Nuclear Information System (INIS)

    Valachis, Antonis; Nearchou, Andreas

    2013-01-01

    Background: The purpose of the meta-analysis was to estimate the effectiveness and toxicity of low activity radioiodine ablation versus high activity in patients with differentiated thyroid cancer (DTC). Design: A systematic review and meta-analysis was performed by including all randomized trials of low activity versus high activity radioiodine ablation after thyroidectomy. Standard meta-analytic procedures were used to analyze the study outcomes. Results: Ten trials were considered eligible and were further analyzed. The pooled risk ratio (RR) of having a successful ablation for an activity of 1100 MBq versus 3700 MBq (seven trials, 1772 patients) was 0.94 (95% CI 0.85 - 1.04, p-value 0.21). The RR for successful ablation when only thyroid hormone withdrawal was used (five trials, 1116 patients) was 0.87 (95% CI 0.72 - 1.06, p-value 0.17) and it was comparable to RR when only recombinant-human TSH (rec-hTSH) (two trials, 812 patients) was used (1.00, 95% CI 0.93 - 1.07, p-value 0.92). Salivary dysfunction, nausea, and neck pain were significantly more frequent among patients with higher dose for ablation. Conclusion: Our meta-analysis provides some evidence from randomized trials that a lower activity of radioiodine ablation is as effective as higher dose after surgery in patients with DTC with lower toxicity

  3. High versus low radioiodine activity in patients with differentiated thyroid cancer - A meta-analysis

    Energy Technology Data Exchange (ETDEWEB)

    Valachis, Antonis [Dept. of Oncology, Maelarsjukhuset., Eskilstuna (Sweden); Univ. of Uppsala,, (Sweden)], e-mail: Valachis@hotmail.com, Antonis.Valachis@akademiska.uu.se; Nearchou, Andreas [Dept, of Oncology, Maelarsjukhuset., Eskilstuna (Sweden); Univ. of Uppsala., Uppsala (Sweden)

    2013-08-15

    Background: The purpose of the meta-analysis was to estimate the effectiveness and toxicity of low activity radioiodine ablation versus high activity in patients with differentiated thyroid cancer (DTC). Design: A systematic review and meta-analysis was performed by including all randomized trials of low activity versus high activity radioiodine ablation after thyroidectomy. Standard meta-analytic procedures were used to analyze the study outcomes. Results: Ten trials were considered eligible and were further analyzed. The pooled risk ratio (RR) of having a successful ablation for an activity of 1100 MBq versus 3700 MBq (seven trials, 1772 patients) was 0.94 (95% CI 0.85 - 1.04, p-value 0.21). The RR for successful ablation when only thyroid hormone withdrawal was used (five trials, 1116 patients) was 0.87 (95% CI 0.72 - 1.06, p-value 0.17) and it was comparable to RR when only recombinant-human TSH (rec-hTSH) (two trials, 812 patients) was used (1.00, 95% CI 0.93 - 1.07, p-value 0.92). Salivary dysfunction, nausea, and neck pain were significantly more frequent among patients with higher dose for ablation. Conclusion: Our meta-analysis provides some evidence from randomized trials that a lower activity of radioiodine ablation is as effective as higher dose after surgery in patients with DTC with lower toxicity.

  4. 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.

  5. Individual Participant Data Meta-Analysis of Mechanical Workplace Risk Factors and Low Back Pain

    Science.gov (United States)

    Shannon, Harry S.; Wells, Richard P.; Walter, Stephen D.; Cole, Donald C.; Côté, Pierre; Frank, John; Hogg-Johnson, Sheilah; Langlois, Lacey E.

    2012-01-01

    Objectives. We used individual participant data from multiple studies to conduct a comprehensive meta-analysis of mechanical exposures in the workplace and low back pain. Methods. We conducted a systematic literature search and contacted an author of each study to request their individual participant data. Because outcome definitions and exposure measures were not uniform across studies, we conducted 2 substudies: (1) to identify sets of outcome definitions that could be combined in a meta-analysis and (2) to develop methods to translate mechanical exposure onto a common metric. We used generalized estimating equation regression to analyze the data. Results. The odds ratios (ORs) for posture exposures ranged from 1.1 to 2.0. Force exposure ORs ranged from 1.4 to 2.1. The magnitudes of the ORs differed according to the definition of low back pain, and heterogeneity was associated with both study-level and individual-level characteristics. Conclusions. We found small to moderate ORs for the association of mechanical exposures and low back pain, although the relationships were complex. The presence of individual-level OR modifiers in such an area can be best understood by conducting a meta-analysis of individual participant data. PMID:22390445

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. Associations between TNFAIP3 gene polymorphisms and systemic lupus erythematosus risk: an updated meta-analysis.

    Science.gov (United States)

    Zhang, M-Y; Yang, X-K; Pan, H-F; Ye, D-Q

    2016-11-01

    In order to determine whether tumor necrosis factor alpha inducible protein 3 (TNFAIP3) gene polymorphisms confers susceptibility to systemic lupus erythematosus (SLE) in ethnically different populations. A meta-analysis was conducted to examine the association between TNFAIP3 polymorphisms and susceptibility to SLE. A systematic literature search was conducted to identify all relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of the association. A total of 23 studies from 20 articles, involving 18,501 patients with SLE and 30,435 healthy controls were included in this meta-analysis. Overall, we found significant association between SLE and the TNFAIP3 rs2230926, rs5029937, rs5029939, and rs3757173 polymorphisms (all P < 0.001). Stratification by ethnicity indicated that rs5029939 polymorphism was associated with SLE in Europeans, while rs2230926, rs5029937, and rs3757173 polymorphisms were associated with SLE both in Europeans and Asians (all P < 0.001). The results of our meta-analysis suggest that TNFAIP3 (rs2230926, rs5029937, rs5029939, and rs3757173) polymorphisms are associated with susceptibility to SLE. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Gait variability in people with neurological disorders: A systematic review and meta-analysis.

    Science.gov (United States)

    Moon, Yaejin; Sung, JongHun; An, Ruopeng; Hernandez, Manuel E; Sosnoff, Jacob J

    2016-06-01

    There has been growing evidence showing gait variability provides unique information about gait characteristics in neurological disorders. This study systemically reviewed and quantitatively synthesized (via meta-analysis) existing evidence on gait variability in various neurological diseases, including Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), cerebellar ataxia (CA), Huntington's disease (HD), multiple sclerosis (MS), and Parkinson's disease (PD). Keyword search were conducted in PubMed, Web of science, Cumulative Index to Nursing and Allied Health Literature, and Cochrane Library. Meta-analysis was performed to estimate the pooled effect size for gait variability for each neurological group. Meta-regression was performed to compare gait variability across multiple groups with neurological diseases. Gait variability of 777 patients with AD, ALS, CA, HD, MS, or PD participating in 25 studies was included in meta-analysis. All pathological groups had increased amount of gait variability and loss of fractal structure of gait dynamics compared to healthy controls, and gait variability differentiated distinctive neurological conditions. The HD groups had the highest alterations in gait variability among all pathological groups, whereas the PD, AD and MS groups had the lowest. Interventions that aim to improve gait function in patients with neurological disorders should consider the heterogeneous relationship between gait variability and neurological conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The Effect of Three Different Meditation Exercises on Hypertension: A Network Meta-Analysis

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    Hongchang Yang

    2017-01-01

    Full Text Available We aimed to use the pairwise and network meta-analysis to estimate the effects of different meditation exercises on the control of systolic blood pressure (SBP and diastolic blood pressure (DBP. Randomized controlled trials (RCTs were retrieved from PubMed and Embase up to June 2016, which are published in English and reported on meditation exercise for hypertensive patients. Risks of bias assessment of the included studies were assessed by Cochrane Collaboration Recommendations and network meta-analysis was performed by ADDIS. Mean difference (MD and its 95% confidence interval (CI were used as the effect size. A number of 19 RCTs were included in this study. Results of pairwise comparisons indicated that meditation exercise could significantly decrease the SBP and DBP, compared with other interventions (MD = −7.10, 95% CI: −10.82 to −3.39; MD = −4.02, 95% CI: −6.12 to −1.92. With good consistence and convergence, network meta-analysis showed that there were no significant differences between meditation and other interventions on SBP. For DBP, Qigong was significantly lower than “no intervention” (MD = −11.73, 95% CI: −19.85 to −3.69. Qigong may be the optimal exercise way in lowering SBP and DBP of hypertensive patients, but a detailed long-term clinical research should be needed in the future.

  15. Meta-analysis of Egg Consumption and Risk of Coronary Heart Disease and Stroke.

    Science.gov (United States)

    Alexander, Dominik D; Miller, Paula E; Vargas, Ashley J; Weed, Douglas L; Cohen, Sarah S

    2016-01-01

    The possible relationship between dietary cholesterol and cardiac outcomes has been scrutinized for decades. However, recent reviews of the literature have suggested that dietary cholesterol is not a nutrient of concern. Thus, we conducted a meta-analysis of egg intake (a significant contributor to dietary cholesterol) and risk of coronary heart disease (CHD) and stroke. A comprehensive literature search was conducted through August 2015 to identify prospective cohort studies that reported risk estimates for egg consumption in association with CHD or stroke. Random-effects meta-analysis was used to generate summary relative risk estimates (SRREs) for high vs low intake and stratified intake dose-response analyses. Heterogeneity was examined in subgroups where sensitivity and meta regression analyses were conducted based on increasing egg intake. A 12% decreased risk (SRRE = 0.88, 95% confidence interval [CI], 0.81-0.97) of stroke was observed in the meta-analysis of 7 studies of egg intake (high vs low; generally 1/d vs egg consumption and CHD. No clear dose-response trends were apparent in the stratified intake meta-analyses or the meta regression analyses. Based on the results of this meta-analysis, consumption of up to one egg daily may contribute to a decreased risk of total stroke, and daily egg intake does not appear to be associated with risk of CHD. Key Teaching Points: • The role of egg consumption in the risk of stroke and coronary heart disease has come under scrutiny over many years. • A comprehensive meta-analysis of prospective cohort studies that reported risk estimates for egg consumption in association with CHD or stroke was performed on the peer-reviewed epidemiologic literature through August 2015. • Overall, summary associations indicate that intake of up to 1 egg daily may be associated with reduced risk of total stroke. • Overall, summary associations show no clear association between egg intake and increased or decreased risk of CHD

  16. Food and drug cues activate similar brain regions: a meta-analysis of functional MRI studies.

    Science.gov (United States)

    Tang, D W; Fellows, L K; Small, D M; Dagher, A

    2012-06-06

    In healthy individuals, food cues can trigger hunger and feeding behavior. Likewise, smoking cues can trigger craving and relapse in smokers. Brain imaging studies report that structures involved in appetitive behaviors and reward, notably the insula, striatum, amygdala and orbital frontal cortex, tend to be activated by both visual food and smoking cues. Here, by carrying out a meta-analysis of human neuro-imaging studies, we investigate the neural network activated by: 1) food versus neutral cues (14 studies, 142 foci) 2) smoking versus neutral cues (15 studies, 176 foci) 3) smoking versus neutral cues when correlated with craving scores (7 studies, 108 foci). PubMed was used to identify cue-reactivity imaging studies that compared brain response to visual food or smoking cues to neutral cues. Fourteen articles were identified for the food meta-analysis and fifteen articles were identified for the smoking meta-analysis. Six articles were identified for the smoking cue correlated with craving analysis. Meta-analyses were carried out using activation likelihood estimation. Food cues were associated with increased blood oxygen level dependent (BOLD) response in the left amygdala, bilateral insula, bilateral orbital frontal cortex, and striatum. Smoking cues were associated with increased BOLD signal in the same areas, with the exception of the insula. However, the smoking meta-analysis of brain maps correlating cue-reactivity with subjective craving did identify the insula, suggesting that insula activation is only found when craving levels are high. The brain areas identified here are involved in learning, memory and motivation, and their cue-induced activity is an index of the incentive salience of the cues. Using meta-analytic techniques to combine a series of studies, we found that food and smoking cues activate comparable brain networks. There is significant overlap in brain regions responding to conditioned cues associated with natural and drug rewards

  17. 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.

  18. 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.

  19. Prognostic value of stromal decorin expression in patients with breast cancer: a meta-analysis.

    Science.gov (United States)

    Li, Shuang-Jiang; Chen, Da-Li; Zhang, Wen-Biao; Shen, Cheng; Che, Guo-Wei

    2015-11-01

    Numbers of studies have investigated the biological functions of decorin (DCN) in oncogenesis, tumor progression, angiogenesis and metastasis. Although many of them aim to highlight the prognostic value of stromal DCN expression in breast cancer, some controversial results still exist and a consensus has not been reached until now. Therefore, our meta-analysis aims to determine the prognostic significance of stromal DCN expression in breast cancer patients. PubMed, EMBASE, the Web of Science and China National Knowledge Infrastructure (CNKI) databases were searched for full-text literatures met out inclusion criteria. We applied the hazard ratio (HR) with 95% confidence interval (CI) as the appropriate summarized statistics. Q-test and I(2) statistic were employed to estimate the level of heterogeneity across the included studies. Sensitivity analysis was conducted to further identify the possible origins of heterogeneity. The publication bias was detected by Begg's test and Egger's test. There were three English literatures (involving 6 studies) included into our meta-analysis. On the one hand, both the summarized outcomes based on univariate analysis (HR: 0.513; 95% CI: 0.406-0.648; Panalysis (HR: 0.544; 95% CI: 0.388-0.763; Panalysis (HR: 0.504; 95% CI: 0.389-0.651; Panalysis (HR: 0.568; 95% CI: 0.400-0.806; P=0.002) also indicated that stromal DCN expression was positively associated with high disease-free survival (DFS) of breast cancer patients. No significant heterogeneity or publication bias was observed within this meta-analysis. The present evidences indicate that high stromal DCN expression can significantly predict the good prognosis in patients with breast cancer. The discoveries from our meta-analysis have better be confirmed in the updated review pooling more relevant investigations in the future.

  20. 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.

  1. 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.

  2. Flipped classroom improves student learning in health professions education: a meta-analysis.

    Science.gov (United States)

    Hew, Khe Foon; Lo, Chung Kwan

    2018-03-15

    The use of flipped classroom approach has become increasingly popular in health professions education. However, no meta-analysis has been published that specifically examines the effect of flipped classroom versus traditional classroom on student learning. This study examined the findings of comparative articles through a meta-analysis in order to summarize the overall effects of teaching with the flipped classroom approach. We focused specifically on a set of flipped classroom studies in which pre-recorded videos were provided before face-to-face class meetings. These comparative articles focused on health care professionals including medical students, residents, doctors, nurses, or learners in other health care professions and disciplines (e.g., dental, pharmacy, environmental or occupational health). Using predefined study eligibility criteria, seven electronic databases were searched in mid-April 2017 for relevant articles. Methodological quality was graded using the Medical Education Research Study Quality Instrument (MERSQI). Effect sizes, heterogeneity estimates, analysis of possible moderators, and publication bias were computed using the COMPREHENSIVE META-ANALYSIS software. A meta-analysis of 28 eligible comparative studies (between-subject design) showed an overall significant effect in favor of flipped classrooms over traditional classrooms for health professions education (standardized mean difference, SMD = 0.33, 95% confidence interval, CI = 0.21-0.46, p flipped classroom approach was more effective when instructors used quizzes at the start of each in-class session. More respondents reported they preferred flipped to traditional classrooms. Current evidence suggests that the flipped classroom approach in health professions education yields a significant improvement in student learning compared with traditional teaching methods.

  3. How acute total sleep loss affects the attending brain: a meta-analysis of neuroimaging studies.

    Science.gov (United States)

    Ma, Ning; Dinges, David F; Basner, Mathias; Rao, Hengyi

    2015-02-01

    Attention is a cognitive domain that can be severely affected by sleep deprivation. Previous neuroimaging studies have used different attention paradigms and reported both increased and reduced brain activation after sleep deprivation. However, due to large variability in sleep deprivation protocols, task paradigms, experimental designs, characteristics of subject populations, and imaging techniques, there is no consensus regarding the effects of sleep loss on the attending brain. The aim of this meta-analysis was to identify brain activations that are commonly altered by acute total sleep deprivation across different attention tasks. Coordinate-based meta-analysis of neuroimaging studies of performance on attention tasks during experimental sleep deprivation. The current version of the activation likelihood estimation (ALE) approach was used for meta-analysis. The authors searched published articles and identified 11 sleep deprivation neuroimaging studies using different attention tasks with a total of 185 participants, equaling 81 foci for ALE analysis. The meta-analysis revealed significantly reduced brain activation in multiple regions following sleep deprivation compared to rested wakefulness, including bilateral intraparietal sulcus, bilateral insula, right prefrontal cortex, medial frontal cortex, and right parahippocampal gyrus. Increased activation was found only in bilateral thalamus after sleep deprivation compared to rested wakefulness. Acute total sleep deprivation decreases brain activation in the fronto-parietal attention network (prefrontal cortex and intraparietal sulcus) and in the salience network (insula and medial frontal cortex). Increased thalamic activation after sleep deprivation may reflect a complex interaction between the de-arousing effects of sleep loss and the arousing effects of task performance on thalamic activity. © 2015 Associated Professional Sleep Societies, LLC.

  4. Ethnic density effects for adult mental health: systematic review and meta-analysis of international studies.

    Science.gov (United States)

    Bécares, Laia; Dewey, Michael E; Das-Munshi, Jayati

    2017-12-14

    Despite increased ethnic diversity in more economically developed countries it is unclear whether residential concentration of ethnic minority people (ethnic density) is detrimental or protective for mental health. This is the first systematic review and meta-analysis covering the international literature, assessing ethnic density associations with mental health outcomes. We systematically searched Medline, PsychINFO, Sociological Abstracts, Web of Science from inception to 31 March 2016. We obtained additional data from study authors. We conducted random-effects meta-analysis taking into account clustering of estimates within datasets. Meta-regression assessed heterogeneity in studies due to ethnicity, country, generation, and area-level deprivation. Our main exposure was ethnic density, defined as the residential concentration of own racial/ethnic minority group. Outcomes included depression, anxiety and the common mental disorders (CMD), suicide, suicidality, psychotic experiences, and psychosis. We included 41 studies in the review, with meta-analysis of 12 studies. In the meta-analyses, we found a large reduction in relative odds of psychotic experiences [odds ratio (OR) 0.82 (95% confidence interval (CI) 0.76-0.89)] and suicidal ideation [OR 0.88 (95% CI 0.79-0.98)] for each 10 percentage-point increase in own ethnic density. For CMD, depression, and anxiety, associations were indicative of protective effects of own ethnic density; however, results were not statistically significant. Findings from narrative review were consistent with those of the meta-analysis. The findings support consistent protective ethnic density associations across countries and racial/ethnic minority populations as well as mental health outcomes. This may suggest the importance of the social environment in patterning detrimental mental health outcomes in marginalized and excluded population groups.

  5. 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.

  6. Methadone Poisoning in Children: A Systematic Review and Meta-Analysis in Iran

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    Yasaman Allameh

    2017-05-01

    Full Text Available Context Symptoms of methadone poisoning, as one of the most dangerous types of poisoning, are very serious in children. Objectives The aim of this study was to describe causes and clinical symptoms of methadone poisoning in children admitted to hospitals in Iran. Data Sources Relevant studies published in national and international journals before January 29, 2016 were identified by studying the available databases, including PubMed, Web of Sciences, Google Scholar, Scopus, SID, Iranmedex, MagIran, and Irandoc. Study Selection After excluding duplicate, irrelevant, and low-quality articles, relevant papers were entered into the meta-analysis. The prevalence, mean, and standard deviation of methadone poisoning symptoms in children were statistically analyzed, using Stata version 11, and causes of methadone poisoning were presented in tables. Data Extraction Studies with unknown sample sizes, abstracts without access to full text, articles with quality assessment scores below 15.5, and studies carried out on non-Iranian populations were excluded from the meta-analysis. Results During the initial advanced search, 1594 articles were identified. After quality assessment, 12 papers were found eligible for the final systematic review and meta-analysis, based on the inclusion and exclusion criteria. The reported symptoms included drowsiness, vomiting, apnea, cyanosis, seizure, ataxia, and delirium. In the meta-analysis, prevalence of symptoms in referred patients was estimated at 44% (0.95% confidence interval, 0.288 to 0.609. The causes of poisoning in children included accidental feeding by parents, storage of drugs in inappropriate containers, parental addiction, and low educational level of parents. Conclusions It is important to keep methadone in a suitable container away from children. Also, it is essential to focus on educating parents on health issues of their children.

  7. Comparison of diagnostic efficacy between CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures: a meta-analysis.

    Science.gov (United States)

    Gao, Ya-Dong; Qu, Ya-Wei; Liu, Hai-Feng

    2018-04-01

    The accurate diagnosis of undetermined pancreaticobiliary strictures remains challenging. Current ERCP-guided tissue sampling methods are of low sensitivity. Confocal laser endomicroscopy (CLE) is a new procedure and allows real optical biopsies that may improve the diagnosis of undetermined pancreaticobiliary strictures. The aim of this meta-analysis was to determine the diagnostic yield of CLE, tissue sampling, and CLE combined with tissue sampling for undetermined pancreaticobiliary strictures. Pubmed, Embase, and the Cochrane Library database were reviewed for relevant studies. Pooled estimates of sensitivity and specificity with 95% confidence intervals (CIs) were calculated using the random-effects meta-analysis model. The summary receiver-operating characteristic (SROC) curve was constructed, and the area under the receiver operating characteristic curve (AUC) was calculated. Twelve studies involving 591 patients were enrolled in our analysis. The overall sensitivity and the specificity estimate of CLE for discriminating benign and malignant pancreaticobiliary strictures were 87% (95%CI, 83-91%) and 76% (95%CI, 70-81%), respectively. The AUC to assess the diagnostic efficacy was 0.8705. For tissue sampling, the overall sensitivity and the specificity estimate were 64% (95%CI, 57-70%) and 94% (95%CI, 90-97%), respectively. The AUC to assess the diagnostic efficacy was 0.8040. A combination of both methods increased the sensitivity (93%; 95%CI, 88-96%) with a specificity of 82% (95%CI, 74-89%). The AUC to assess the diagnostic efficacy was 0.9377. There was no publication bias by Deeks' Funnel Plot with p = .936. Compared with tissue sampling, CLE may increase the sensitivity for the diagnosis of malignant pancreaticobiliary strictures. A combination of both can effectively diagnose malignant pancreaticobiliary strictures.

  8. Challenges associated with drunk driving measurement: combining police and self-reported data to estimate an accurate prevalence in Brazil.

    Science.gov (United States)

    Sousa, Tanara; Lunnen, Jeffrey C; Gonçalves, Veralice; Schmitz, Aurinez; Pasa, Graciela; Bastos, Tamires; Sripad, Pooja; Chandran, Aruna; Pechansky, Flavio

    2013-12-01

    Drunk driving is an important risk factor for road traffic crashes, injuries and deaths. After June 2008, all drivers in Brazil were subject to a "Zero Tolerance Law" with a set breath alcohol concentration of 0.1 mg/L of air. However, a loophole in this law enabled drivers to refuse breath or blood alcohol testing as it may self-incriminate. The reported prevalence of drunk driving is therefore likely a gross underestimate in many cities. To compare the prevalence of drunk driving gathered from police reports to the prevalence gathered from self-reported questionnaires administered at police sobriety roadblocks in two Brazilian capital cities, and to estimate a more accurate prevalence of drunk driving utilizing three correction techniques based upon information from those questionnaires. In August 2011 and January-February 2012, researchers from the Centre for Drug and Alcohol Research at the Universidade Federal do Rio Grande do Sul administered a roadside interview on drunk driving practices to 805 voluntary participants in the Brazilian capital cities of Palmas and Teresina. Three techniques which include measures such as the number of persons reporting alcohol consumption in the last six hours but who had refused breath testing were used to estimate the prevalence of drunk driving. The prevalence of persons testing positive for alcohol on their breath was 8.8% and 5.0% in Palmas and Teresina respectively. Utilizing a correction technique we calculated that a more accurate prevalence in these sites may be as high as 28.2% and 28.7%. In both cities, about 60% of drivers who self-reported having drank within six hours of being stopped by the police either refused to perform breathalyser testing; fled the sobriety roadblock; or were not offered the test, compared to about 30% of drivers that said they had not been drinking. Despite the reduction of the legal limit for drunk driving stipulated by the "Zero Tolerance Law," loopholes in the legislation permit many

  9. Sleep duration and obesity in children: A systematic review and meta-analysis of prospective cohort studies.

    Science.gov (United States)

    Li, Lian; Zhang, Shuang; Huang, Yubei; Chen, Kexin

    2017-04-01

    Childhood obesity is a major public problem worldwide, and sleep duration may be associated with childhood obesity. We conducted a systematic review and meta-analysis of prospective cohort studies to estimate the associations between sleep duration and obesity/body mass index (BMI) in children. PubMed, Embase and the Cochrane Library were searched. For the meta-analysis, the pooled relative risk (RR) and 95% confidence intervals (CI) were estimated to reveal the association between short sleep duration and obesity. For the review, the outcomes focused on BMI change or subsequent BMI status. A total of 12 studies (15 populations) met the criteria for inclusion in the meta-analysis. Short sleep duration was significantly associated with obesity (RR: 1.45; 95% CI: 1.14-1.85). After excluding two cohorts that substantially affected the heterogeneity, the pooled results remained significant (RR: 1.30; 95% CI: 1.20-1.42), and the association was not substantially altered in the subgroup analysis. In addition, we summarised 24 studies that met the criteria for our review of the relationship between sleeping and BMI. The present meta-analysis indicated that short sleep duration increased the risk of childhood obesity. Public health efforts that encourage children to have sufficient sleep time may be important in combating obesity. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  10. Robotic partial nephrectomy for renal tumors larger than 4 cm: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Liangkuan Bi

    Full Text Available BACKGROUND: With the establishment of minimally invasive surgery in society, the robot has been increasingly widely used in the urologic field, including in partial nephrectomy. This study aimed to comprehensively summarize the currently available evidence on the feasibility and safety of robotic partial nephrectomy for renal tumors of >4 cm. METHOD AND FINDINGS: An electronic database search of PubMed, Scopus, Web of Science, and the Cochrane Library was performed. This systematic review and meta-analysis was based on all relevant studies that assessed robotic partial nephrectomy for renal tumors of >4 cm. Five studies were included. The meta-analysis involved 3 studies from 11 institutions including 154 patients, while the narrative review involved the remaining 2 studies from 5 institutions including 64 patients. In the meta-analysis, the mean ischemic time, operation time, and console time was 28, 319, and 189 minutes, respectively. The estimated blood loss and length of stay was 317 ml and 3.8 days, respectively. The rates of conversion, positive margins, intraoperative complications, postoperative complications, hilar clamping, and collecting system repair were 7.0%, 3.5%, 7.0%, 9.8%, 93.9%, and 47.5%, respectively. The narrative review showed results similar to those of the meta-analysis. CONCLUSIONS: Robotic partial nephrectomy is feasible and safe for renal tumors of >4 cm with an acceptable warm ischemic time, positive margin rate, conversion rate, complication rate, operation time, estimated blood loss, and length of stay.

  11. 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.

  12. 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.

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

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    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.

  14. 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.

  15. 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.

  16. Existing equations to estimate lean body mass are not accurate in the critically ill: Results of a multicenter observational study.

    Science.gov (United States)

    Moisey, Lesley L; Mourtzakis, Marina; Kozar, Rosemary A; Compher, Charlene; Heyland, Daren K

    2017-12-01

    Lean body mass (LBM), quantified using computed tomography (CT), is a significant predictor of clinical outcomes in the critically ill. While CT analysis is precise and accurate in measuring body composition, it may not be practical or readily accessible to all patients in the intensive care unit (ICU). Here, we assessed the agreement between LBM measured by CT and four previously developed equations that predict LBM using variables (i.e. age, sex, weight, height) commonly recorded in the ICU. LBM was calculated in 327 critically ill adults using CT scans, taken at ICU admission, and 4 predictive equations (E1-4) that were derived from non-critically adults since there are no ICU-specific equations. Agreement was assessed using paired t-tests, Pearson's correlation coefficients and Bland-Altman plots. Median LBM calculated by CT was 45 kg (IQR 37-53 kg) and was significantly different (p equations overestimated LBM (error ranged from 7.5 to 9.9 kg), compared with LBM calculated by CT, suggesting insufficient agreement. Our data indicates a large bias is present between the calculation of LBM by CT imaging and the predictive equations that have been compared here. This underscores the need for future research toward the development of ICU-specific equations that reliably estimate LBM in a practical and cost-effective manner. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  17. Diverticulitis in young versus elderly patients: a meta-analysis.

    Science.gov (United States)

    van de Wall, Bryan J M; Poerink, Jolien A; Draaisma, Werner A; Reitsma, Johannes B; Consten, Esther C J; Broeders, Ivo A M J

    2013-06-01

    To compare patients younger and older than 50 years with diverticulitis with regard to complications, disease recurrence and to the need for surgery. A literature review and meta-analysis was conducted according to the PRISMA guidelines. MEDLINE, Embase and the Cochrane databases were searched for longitudinal cohort studies comparing patients younger and older than 50 years with diverticulitis. Eight studies were included with a total of 4.751 (male:female 1:0.66) patients younger and 18.328 (male:female 1:1.67) older than 50 years of age. The risk of developing at least one recurrent episode was significantly higher among patients younger than 50 years (pooled RR 1.73; 95% CI 1.40-2.13) with an estimated cumulative risk of 30% compared with 17.3% in older patients. The risk of requiring surgery during hospitalization for a primary episode of diverticulitis was equal in both age groups (pooled RR 0.99; 95% CI 0.74-1.32) and estimated at approximately 20%. Patients younger than 50 years more frequently required urgent surgery during hospitalization for a subsequent recurrent episode (pooled RR 1.46; 95% CI 1.29-1.66); the cumulative risk was 7.3% in younger and 4.9% in patients older than 50 years. Patients younger than 50 years only differ substantially in risk for recurrent disease from patients older than 50 years of age. Although the relative risk for requiring urgent surgery for recurrent disease was higher in younger patient, one should consider that the absolute risk difference is relatively small (7.3% vs. 4.9%).

  18. Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

    Science.gov (United States)

    Griffin, T W; Zapata, S D

    2016-08-01

    The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the

  19. 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.

  20. An accurate procedure for estimating the phase speed of ocean waves from observations by satellite borne altimeters

    Science.gov (United States)

    De-Leon, Yair; Paldor, Nathan

    2017-08-01

    Observations of sea surface height (SSH) fields using satellite borne altimeters were conducted starting in the 1990s in various parts of the world ocean. Currently, a long period of 20 years of calibrated and accurate altimeter observations of Sea Surface Height Anomalies (SSHA) is publically available and ready to be examined for determining the rate of westward propagation of these anomalies, which are interpreted as a surface manifestation of linear Rossby waves that propagate westward in the ocean thermocline or as nonlinear eddies. The basis for estimating the speed of westward propagation of SSHA is time-longitude (Hovmöller) diagrams of the SSHA field at fixed latitude. In such a diagram the westward propagation is evident from a left-upward tilt of constant SSHA values (i.e. contours) and the angle between this tilt and the ordinate is directly proportional to the speed of westward propagation. In this work we use synthetically generated noisy data to examine the accuracy of three different methods that have been separately used in previous studies for estimating this slope (angle) of the time-longitude diagram: The first is the application of Radon transform, used in image processing for detecting structures on an image. The second method is the application of 2D Fast Fourier Transform that yields a frequency-wavenumber diagram of the amplitudes so the frequency and wavenumber where the maximum amplitude occurs determine the phase speed i.e. the slope. The third method constitutes an adaptation of Radon transform to a propagating wave in which structures of minimal variance in the image are identified. The three methods do not always yield the same phase speed value and our analysis of the synthetic data shows that an estimate of the phase speed at any given latitude should be considered valid only when at least two of the methods yield the same value. The relevance of the suggested procedure to observed signals is verified by applying it to observed

  1. Epilepsy and neurocysticercosis in Latin America: a systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Elisa Bruno

    Full Text Available The difference in epilepsy burden existing among populations in tropical regions has been attributed to many factors, including the distribution of infectious diseases with neurologic sequels. To define the burden of epilepsy in Latin American Countries (LAC and to investigate the strength of association with neurocysticercosis (NCC, considered one of the leading causes of epilepsy, we performed a systematic review and meta-analysis of the literature.Studies published until 2012 were selected applying predefined inclusion criteria. Lifetime epilepsy (LTE prevalence, active epilepsy (AE prevalence, incidence, mortality, treatment gap (TG and NCC proportion among people with epilepsy (PWE were extracted. Median values were obtained for each estimate using random effects meta-analysis. The impact of NCC prevalence on epilepsy estimates was determined using meta-regression models. To assess the association between NCC and epilepsy, a further meta-analysis was performed on case-control studies.The median LTE prevalence was 15.8/1,000 (95% CI 13.5-18.3, the median AE prevalence was 10.7/1,000 (95% CI 8.4-13.2, the median incidence was 138.2/100,000 (95% CI 83.6-206.4, the overall standardized mortality ratio was 1.4 (95% CI 0.01-6.1 and the overall estimated TG was 60.6% (95% CI 45.3-74.9. The median NCC proportion among PWE was 32.3% (95% CI 26.0-39.0. Higher TG and NCC estimates were associated with higher epilepsy prevalence. The association between NCC and epilepsy was significant (p<0.001 with a common odds ratio of 2.8 (95% CI 1.9-4.0.A high burden of epilepsy and of NCC in LAC and a consistent association between these two diseases were pointed out. Furthermore, NCC prevalence and TG were identified as important factors influencing epilepsy prevalence to be considered in prevention and intervention strategies.

  2. 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.

  3. The prevalence of chronic fatigue syndrome/ myalgic encephalomyelitis: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Johnston S

    2013-03-01

    Full Text Available Samantha Johnston,1 Ekua W Brenu,1 Donald Staines,1,2 Sonya Marshall-Gradisnik1 1Griffith Health Institute, School of Medical Sciences, National Centre for Neuroimmunology and Emerging Diseases, Griffith University, Parklands, QLD, Australia; 2Gold Coast Public Health Unit, Queensland Health, Robina, QLD, Australia Purpose: To perform a meta-analysis to examine variability among prevalence estimates for CFS/ME, according to the method of assessment used. Methods: Databases were systematically searched for studies on CFS/ME prevalence in adults that applied the 1994 Centers for Disease Control (CDC case definition.1 Estimates were categorized into two methods of assessment: self-reporting of symptoms versus clinical assessment of symptoms. Meta-analysis was performed to pool prevalences by assessment using random effects modeling. This was stratified by sample setting (community or primary care and heterogeneity was examined using the I2 statistic. Results: Of 216 records found, 14 studies were considered suitable for inclusion. The pooled prevalence for self-reporting assessment was 3.28% (95% CI: 2.24–4.33 and 0.76% (95% CI: 0.23–1.29 for clinical assessment. High variability was observed among self-reported estimates, while clinically assessed estimates showed greater consistency. Conclusion: The observed heterogeneity in CFS/ME prevalence may be due to differences in method of assessment. Stakeholders should be cautious of prevalence determined by the self-reporting of symptoms alone. The 1994 CDC case definition appeared to be the most reliable clinical assessment tool available at the time of these studies. Improving clinical case definitions and their adoption internationally will enable better comparisons of findings and inform health systems about the true burden of CFS/ME. Keywords: chronic fatigue syndrome, myalgic encephalomyelitis, prevalence, meta-analysis

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

    Science.gov (United States)

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

    2013-08-01

    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 that compares the performance of different methods of meta-analysis, especially with respect to model-based health economic (HE) outcomes. A reference patient population of 50,000 was simulated from which sets of samples were drawn. Each sample drawn represented a clinical trial comparing two fictitious interventions. In several scenarios, the heterogeneity between these trials was varied, by drawing one or more of the trials from predefined subpopulations. Parameter estimates from these trials were combined using frequentist fixed (FFE) and random effects (FRE), and Bayesian fixed (BFE) and random effects (BRE) meta-analysis. The pooled parameter estimates were entered into a probabilistic cost-effectiveness Markov model. The four methods of meta-analysis resulted in different parameter estimates and HE outcomes, which were compared with the true values in the reference population. Performance statistics were: (1) the percentage of repetitions that the confidence interval of the probabilistic sensitivity analysis covers the true value (coverage), (2) the difference between the estimated and true value (bias), (3) the mean absolute value of the bias (MAD) and (4) the percentage of repetitions that result in a statistically significant difference between the two interventions (statistical power). As the differences between methods could be due to chance, we repeated every step of the analysis 1,000 times to study whether differences were systematic. FFE, FRE and BFE lead to different parameter estimates, but, when entered into the model, they do not lead to large differences in the point estimates of the HE outcomes, even in scenarios where we built in heterogeneity

  5. 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.

  6. Early Response to treatment in Eating Disorders: A Systematic Review and a Diagnostic Test Accuracy Meta-Analysis.

    Science.gov (United States)

    Nazar, Bruno Palazzo; Gregor, Louise Kathrine; Albano, Gaia; Marchica, Angelo; Coco, Gianluca Lo; Cardi, Valentina; Treasure, Janet

    2017-03-01

    Early response to eating disorders treatment is thought to predict a later favourable outcome. A systematic review of the literature and meta-analyses examined the robustness of this concept. The criteria used across studies to define early response were summarised following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Diagnostic Test Accuracy methodology was used to estimate the size of the effect. Findings from 24 studies were synthesized and data from 14 studies were included in the meta-analysis. In Anorexia Nervosa, the odds ratio of early response predicting remission was 4.85(95%CI: 2.94-8.01) and the summary Area Under the Curve (AUC) = .77. In Bulimia Nervosa, the odds ratio was 2.75(95%CI:1.24-6.09) and AUC = .67. For Binge Eating Disorder, the odds ratio was 5.01(95%CI: 3.38-7.42) and AUC = .71. Early behaviour change accurately predicts later symptom remission for Anorexia Nervosa and Binge Eating Disorder but there is less predictive accuracy for Bulimia Nervosa. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2016 John Wiley & Sons, Ltd and Eating Disorders Association.

  7. Subtypes of Benign Breast Disease as a Risk Factor for Breast Cancer: A Systematic Review and Meta-Analysis Protocol

    Directory of Open Access Journals (Sweden)

    Manoosh Zendehdel

    2018-01-01

    Full Text Available Breast cancer is a multifactorial disease. Benign breast disease (BBD is one of the most important risk factors for breast cancer. The etiology of BBD is unknown. It is divided into nonproliferative and proliferative diseases. The selection of studies will be based on titles, abstract screening, inclusion and exclusion criteria, and quality assessment. Previous studies have shown that all types of BBD increase the risk of breast cancer, but the risk degree is different for each one. Accurate risk estimation of breast cancer in each category can be very important for proper clinical management. This systematic review and meta-analysis will be conducted on observational studies (traditional case control, nested case control, case cohort, and cohort published in the Web of Science (ISI, PubMed (MEDLINE, Scopus, Google Scholar, and the key journals of this field such as Breast Cancer Research and Treatment and Cancer Research from January 2000 to June 2015. Reference lists and gray literature will be reviewed too. All the initial retrievals will be performed by 2 researchers independently. The data extraction form will consist of general information concerning the studies, study eligibility, method, risk of bias assessment, and results—including odds ratios, risk ratios, rate ratios, and hazard ratios. The PRISMA and MOOSE guidelines will be used to report our findings. Registration Details: PROSPERO-42016035243

  8. 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

  9. Is chronic toxoplasmosis a risk factor for diabetes mellitus? A systematic review and meta-analysis of case–control studies

    Directory of Open Access Journals (Sweden)

    Hamidreza Majidiani

    2016-11-01

    Conclusion: Despite the limitations such as low number of studies, this meta-analysis suggests chronic toxoplasmosis as a possible risk factor for type 2 DM. However, based on random effects model no statistically significant association was observed between T. gondii and type 1 DM. It is highly recommended for researchers to carry out more accurate studies aiming to better understand this association.

  10. How accurate are adolescents in portion-size estimation using the computer tool young adolescents' nutrition assessment on computer (YANA-C)?

    OpenAIRE

    Vereecken, Carine; Dohogne, Sophie; Covents, Marc; Maes, Lea

    2010-01-01

    Computer-administered questionnaires have received increased attention for large-scale population research on nutrition. In Belgium-Flanders, Young Adolescents' Nutrition Assessment on Computer (YANA-C) has been developed. In this tool, standardised photographs are available to assist in portion-size estimation. The purpose of the present study is to assess how accurate adolescents are in estimating portion sizes of food using YANA-C. A convenience sample, aged 11-17 years, estimated the amou...

  11. C-reactive protein gene polymorphisms and myocardial infarction risk: a meta-analysis and meta-regression.

    Science.gov (United States)

    Zhu, Yanbin; Liu, Tongku; He, Haitao; Sun, Yuqing; Zhuo, Fengling

    2013-12-01

    C-reactive protein (CRP), the classic acute-phase protein, plays an important role in the etiology of myocardial infarction (MI). Emerging evidence has shown that the common polymorphisms in the CRP gene may influence an individual's susceptibility to MI; but individually published studies showed inconclusive results. This meta-analysis aimed to derive a more precise estimation of the associations between CRP gene polymorphisms and MI risk. A literature search of PubMed, Embase, Web of Science, and China BioMedicine (CBM) databases was conducted on articles published before June 1st, 2013. Crude odds ratio (OR) with 95% confidence interval (CI) were calculated. Nine case-control studies were included with a total of 2992 MI patients and 4711 healthy controls. The meta-analysis results indicated that CRP rs3093059 (T>C) polymorphism was associated with decreased risk of MI, especially among Asian populations. However, similar associations were not observed in CRP rs1800947 (G>C) and rs2794521 (G>A) polymorphisms (all p>0.05) among both Asian and Caucasian populations. Univariate and multivariate meta-regression analyses showed that ethnicity may be a major source of heterogeneity. No publication bias was detected in this meta-analysis. In conclusion, the current meta-analysis indicates that CRP rs3093059 (T>C) polymorphism may be associated with decreased risk of MI, especially among Asian populations.

  12. 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.

  13. Mobile phone use and risk for intracranial tumors and salivary gland tumors – A meta-analysis

    Directory of Open Access Journals (Sweden)

    Alicja Bortkiewicz

    2017-02-01

    Full Text Available Results of epidemiological studies on the association between use of mobile phone and brain cancer are ambiguous, as well as the results of 5 meta-analysis studies published to date. Since the last meta-analysis (2009, new case-control studies have been published, which theoretically could affect the conclusions on this relationship. Therefore, we decided to perform a new meta-analysis. We conducted a systematic review of multiple electronic data bases for relevant publications. The inclusion criteria were: original papers, case-control studies, published till the end of March 2014, measures of association (point estimates as odds ratio and confidence interval of the effect measured, data on individual exposure. Twenty four studies (26 846 cases, 50 013 controls were included into the meta-analysis. A significantly higher risk of an intracranial tumor (all types was noted for the period of mobile phone use over 10 years (odds ratio (OR = 1.324, 95% confidence interval (CI: 1.028–1.704, and for the ipsilateral location (OR = 1.249, 95% CI: 1.022–1.526. The results support the hypothesis that long-term use of mobile phone increases risk of intracranial tumors, especially in the case of ipsilateral exposure. Further studies are needed to confirm this relationship. Int J Occup Med Environ Health 2017;30(1:27–43

  14. 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.

  15. Comparison between transrectal and transperineal prostate biopsy for detection of prostate cancer: a meta-analysis and trial sequential analysis.

    Science.gov (United States)

    Xue, Jianxin; Qin, Zhiqiang; Cai, Hongzhou; Zhang, Chuanjie; Li, Xiao; Xu, Weizhang; Wang, Jingyuan; Xu, Zicheng; Yu, Bin; Xu, Ting; Zou, Qin

    2017-04-04

    To systematically assess the efficacy and complications of transrectal (TR) versus transperineal (TP) prostate biopsy in the detection of prostate cancer (PCa). A meta-analysis was performed by searching the databases Pubmed, Embase and Web of science for the relevant available studies until September 1st, 2016, and thirteen studies met the inclusion criteria. The pooled odds ratios with 95% confidence intervals were calculated to evaluate the differences of TR and TP groups in PCa detection rate. Then, trial sequential analysis was performed to reduce the risk of type I error and estimated whether the evidence of the results was reliable. Overall, this meta-analysis included a total of 4280 patients, who had been accrued between April 2000 and Aug 2014 and randomly divided into TR group and TP group. Prostate biopsies included sextant, extensive and saturation biopsy procedures. Patients who received TP prostate biopsy had no significant improvement in PCa detection rate, comparing TR group. Moreover, when comparing TR and TP studies, no significant difference was found in abnormal DRE findings, serum PSA level measurement, Gleason score, prostate volume. Besides, this meta-analysis showed no obvious differences between these two groups in terms of relevant complications. Therefore, this meta-analysis revealed that no significant differences were found in PCa detection rate between TP and TR approaches for prostate biopsy. However, with regard to pain relief and additional anesthesia, TR prostate needle biopsy was relatively preferable, compared to TP prostate biopsy.

  16. 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 signifi