Beneficial intergenerational effects of exercise on brain and cognition: a multilevel meta‐analysis of mean and variance

2021 ◽  
Author(s):  
Yefeng Yang ◽  
Malgorzata Lagisz ◽  
Yong Zhi Foo ◽  
Daniel W. A. Noble ◽  
Hamza Anwer ◽  
...  
Keyword(s):  
Meta Analysis ◽  
Intergenerational Effects ◽  
Mean And Variance

Statistical analysis of nematode counts from interlaboratory proficiency tests

Nematology ◽  
2014 ◽  
Vol 16 (2) ◽  
pp. 229-243 ◽  
Author(s):  
Wim Van Den Berg ◽  
Olaf Hartsema ◽  
Loes J.M.F. Den Nijs
Keyword(s):  
Statistical Analysis ◽  
Proficiency Test ◽  
Meta Analysis ◽  
Proficiency Tests ◽  
Free Living ◽  
Accuracy And Precision ◽  
Mean And Variance ◽  
The Mean ◽  
Interaction Variance

A series of proficiency tests on potato cyst nematode (PCN; ) and free-living stages of Meloidogyne and Pratylenchus () were investigated to determine the accuracy and precision of the nematode counts and to gain insights into possible trends and potential improvements. In each test, each participating laboratory received ten samples of soil collected from naturally infested fields and well mixed before distribution. The variance between the counts from the ten samples, estimated per test and laboratory, was constant for PCN cysts and free-living stages of Meloidogyne spp. and Pratylenchus spp. during the period monitored. However, during the initial years, the variance between the samples showed a downward trend for PCN living juveniles. The variance between the laboratories, estimated per test, was constant for PCN cysts over the period 1994-2010. For PCN living juveniles the variance between laboratory means declined from 1994-2000 and from 2000 it was more or less constant, which coincided with the introduction of a well-described new methodology. For Meloidogyne spp. and Pratylenchus spp., from 1998-2005 the variance between laboratory means was more or less constant or increased. From 2006, all participating laboratories incubated the organic matter and the variance between the laboratories was stable and below the levels observed during 2003-2005. After discarding data from initial years with unstable variances of the nematode counts, a meta-analysis was carried out on the remaining data using HGLMs to model the mean and variance of the counts simultaneously. The within-laboratory variance for the ten samples and the interaction variance of test and laboratory were estimated and combined to percentage coefficient of variation (%CV) per laboratory. For PCN cysts, %CV per laboratory ranged from 12.6 to 41.6 and for PCN juveniles in sandy soil from 24.4 to 67.4 and in loamy soil from 37.9 to 102.0. For Meloidogyne spp., %CV ranged from 53.2 to 84.4 and for Pratylenchus spp. from 24.3 to 90.6. The quality of a proficiency test is largely defined by random distribution of the nematodes over the samples allocated, statistical analysis of the data and communication of the results to participating laboratories. This study provides insights into the accuracy and precision at laboratories in recent years and the effect of concerted actions during the period in which the proficiency tests were conducted.

scholarly journals A Bayesian Meta-Analysis on Published Sample Mean and Variance Pharmacokinetic Data with Application to Drug–Drug Interaction Prediction

2008 ◽  
Vol 18 (6) ◽  
pp. 1063-1083 ◽  
Author(s):  
Menggang Yu ◽  
Seongho Kim ◽  
Zhiping Wang ◽  
Stephen Hall ◽  
Lang Li
Keyword(s):  
Drug Interaction ◽  
Meta Analysis ◽  
Pharmacokinetic Data ◽  
Sample Mean ◽  
Interaction Prediction ◽  
Mean And Variance ◽  
Drug Drug Interaction

No Evidence of Creative Benefit Accompanying Dyslexia: A Meta-Analysis

2021 ◽  
pp. 002221942110103
Author(s):  
Florina Erbeli ◽  
Peng Peng ◽  
Marianne Rice
Keyword(s):  
Random Effects ◽  
Variance Estimation ◽  
Meta Analysis ◽  
Robust Variance ◽  
Summary Effect ◽  
Significant Performance ◽  
Mean And Variance ◽  
Robust Variance Estimation ◽  
The Mean ◽  
Creativity Task

Research on the question of creative benefit accompanying dyslexia has produced conflicting findings. In this meta-analysis, we determined summary effects of mean and variance differences in creativity between groups with and without dyslexia. Twenty studies were included ( n = 770 individuals with dyslexia, n = 1,671 controls). A random-effects robust variance estimation (RVE) analysis indicated no mean ( g = −0.02, p = .84) or variance differences ( g = −0.0004, p = .99) in creativity between groups. The mean summary effect was moderated by age, gender, and creativity domain. Compared with adolescents, adults with dyslexia showed an advantage over nondyslexic adults in creativity. In addition, a higher proportion of males in the dyslexia group was associated with poorer performance compared with the controls. Finally, the dyslexia group showed a significant performance disadvantage in verbal versus figural creativity. Regarding variance differences, they varied across age and creativity domains. Compared with adults, adolescents showed smaller variability in the dyslexia group. If the creativity task measured verbal versus figural or combined creativity, then the dyslexia group exhibited smaller variability. Altogether, our results suggest that individuals with dyslexia as a group are no more creative or show greater variability in creativity than peers without dyslexia.

Meta-Analysis

1992 ◽  
Vol 17 (4) ◽  
pp. 279-296 ◽  
Author(s):  
Larry V. Hedges
Keyword(s):  
Random Effects ◽  
Mixed Models ◽  
Fixed Effects ◽  
Meta Analysis ◽  
Statistical Significance ◽  
Fixed And Random Effects ◽  
Mean And Variance ◽  
The Mean ◽  
Combining Estimates ◽  
Effect Magnitude

The use of statistical methods to combine the results of independent empirical research studies (meta-analysis) has a long history. Meta-analytic work can be divided into two traditions: tests of the statistical significance of combined results and methods for combining estimates across studies. The principal classes of combined significance tests are reviewed, and the limitations of these tests are discussed. Fixed effects approaches treat the effect magnitude parameters to be estimated as a consequence of a model involving fixed but unknown constants. Random effects approaches treat effect magnitude parameters as if they were sampled from a universe of effects and attempt to estimate the mean and variance of the hyperpopulation of effects. Mixed models incorporate both fixed and random effects. Finally, areas of current research are summarized, including methods for handling missing data, models for publication selection, models to handle studies that are not independent, and distribution-free models for random effects.

scholarly journals Non-additive genetic effects induce novel phenotypic distributions in male mating traits of F1 hybrids

2020 ◽  
Author(s):  
Keisuke Atsumi ◽  
Malgorzata Lagisz ◽  
Shinichi Nakagawa
Keyword(s):  
Animal Species ◽  
Maternal Inheritance ◽  
Phenotypic Variability ◽  
Meta Analysis ◽  
F1 Hybrids ◽  
Male Mating ◽  
Species Pairs ◽  
Mean And Variance ◽  
Additive Genetic Effects ◽  
Phenotypic Novelty

Hybridization is a source of phenotypic novelty and variation because of increased additive genetic variation. Yet, the roles of non-additive allelic interactions in shaping phenotypic mean and variance of hybrids have been underappreciated. Here we examine the distributions of male-mating traits in F1 hybrids via a meta-analysis of 3208 effect sizes from 39 animal species pairs. Although additivity sets phenotypic distributions of F1s to be intermediate, F1s also showed dominance and maternal inheritance. F1s expressed novel phenotypes (beyond the range of both parents) in 65% of species pairs, often associated with increased phenotypic variability. Overall, however, F1s expressed smaller variation than parents in 51% of traits. While genetic divergence between parents did not impact phenotypic novelty, it increased phenotypic variability of F1s. By creating novel phenotypes with increased variability, non-additivity of heterozygotic genome may play key roles in determining mating success of F1s, and their subsequent extinction or speciation.

scholarly journals Transgenerational effects of obesogenic diets in rodents: a meta-analysis

2021 ◽  
Author(s):  
Hamza Anwer ◽  
Margaret Morris ◽  
Daniel W.A. Noble ◽  
Shinichi Nakagawa ◽  
Malgorzata Lagisz
Keyword(s):  
High Fat Diet ◽  
Meta Analysis ◽  
Health Condition ◽  
Adverse Outcomes ◽  
High Fat ◽  
Transgenerational Effects ◽  
Major Health ◽  
Obesogenic Diet ◽  
Mean And Variance ◽  
The Mean

Obesity is a major health condition that affects millions worldwide. There is an increased interest in understanding the adverse outcomes associated with obesogenic diets. A multitude of studies have investigated the transgenerational impacts of maternal and parental obesogenic diets on subsequent generations of offspring, but results have largely been mixed. We conducted a systematic review and meta-analysis on rodent studies to elucidate how obesogenic diets impact the mean and variance of grand-offspring traits. Our study focused on transgenerational effects (i.e., F2 and F3 generations) in one-off and multigenerational exposure studies. From 33 included articles, we obtained 407 effect sizes representing pairwise comparisons of control and treatment grand-offspring groups pertaining to measures of body weight, adiposity, glucose, insulin, leptin, and triglycerides. We found evidence that male and female grand-offspring descended from grandparents exposed to an obesogenic diet displayed phenotypes consistent with metabolic syndrome, especially in cases where the obesogenic diet was continued across generations. Further, we found stronger evidence for the effects of grand-maternal than grand-paternal exposure on grand-offspring traits. A high-fat diet in one-off exposure studies did not seem to impact phenotypic variation, whereas in multigenerational exposure studies it reduced variation in several traits.

scholarly journals Intergenerational effects of nutrition on immunity: a systematic review and meta-analysis

2017 ◽  
Vol 93 (2) ◽  
pp. 1108-1124
Author(s):  
Catherine E. Grueber ◽  
Lindsey J. Gray ◽  
Katrina M. Morris ◽  
Stephen J. Simpson ◽  
Alistair M. Senior
Keyword(s):  
Systematic Review ◽  
Meta Analysis ◽  
Intergenerational Effects

The effects of low-ratio n-6/n-3 PUFA on biomarkers of inflammation: a systematic review and meta-analysis

2021 ◽  
Author(s):  
Yali Wei ◽  
Yan Meng ◽  
Na Li ◽  
Qian Wang ◽  
Liyong Chen
Keyword(s):  
Systematic Review ◽  
Fatty Acid ◽  
Polyunsaturated Fatty Acid ◽  
Meta Analysis ◽  
Chain Polyunsaturated Fatty Acid ◽  
Inflammation Markers ◽  
Pufa Supplementation ◽  
Long Chain

The purpose of the systematic review and meta-analysis was to determine if low-ratio n-6/n-3 long-chain polyunsaturated fatty acid (PUFA) supplementation affects serum inflammation markers based on current studies.

A meta-analysis of individualized instruction in dental education

1992 ◽  
Vol 56 (3) ◽  
pp. 183-189 ◽  
Author(s):  
LS Dacanay ◽  
PA Cohen
Keyword(s):  
Dental Education ◽  
Meta Analysis ◽  
Individualized Instruction
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