Aspects of First Year Statistics Students' Reasoning When Performing Intuitive Analysis of Variance: Effects of Within- and Between-Group Variability

ERIC Educational Resources Information Center

Trumpower, David L.

2015-01-01

Making inferences about population differences based on samples of data, that is, performing intuitive analysis of variance (IANOVA), is common in everyday life. However, the intuitive reasoning of individuals when making such inferences (even following statistics instruction), often differs from the normative logic of formal statistics. The…

Statistical properties of the radiation belt seed population

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyd, A. J.; Spence, H. E.; Huang, C. -L.

Here, we present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈0.73 with a time lag of 10–15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of themore » acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.« less

Statistical properties of the radiation belt seed population

DOE PAGES

Boyd, A. J.; Spence, H. E.; Huang, C. -L.; ...

2016-07-25

Here, we present a statistical analysis of phase space density data from the first 26 months of the Van Allen Probes mission. In particular, we investigate the relationship between the tens and hundreds of keV seed electrons and >1 MeV core radiation belt electron population. Using a cross-correlation analysis, we find that the seed and core populations are well correlated with a coefficient of ≈0.73 with a time lag of 10–15 h. We present evidence of a seed population threshold that is necessary for subsequent acceleration. The depth of penetration of the seed population determines the inner boundary of themore » acceleration process. However, we show that an enhanced seed population alone is not enough to produce acceleration in the higher energies, implying that the seed population of hundreds of keV electrons is only one of several conditions required for MeV electron radiation belt acceleration.« less

A Matlab user interface for the statistically assisted fluid registration algorithm and tensor-based morphometry

NASA Astrophysics Data System (ADS)

Yepes-Calderon, Fernando; Brun, Caroline; Sant, Nishita; Thompson, Paul; Lepore, Natasha

2015-01-01

Tensor-Based Morphometry (TBM) is an increasingly popular method for group analysis of brain MRI data. The main steps in the analysis consist of a nonlinear registration to align each individual scan to a common space, and a subsequent statistical analysis to determine morphometric differences, or difference in fiber structure between groups. Recently, we implemented the Statistically-Assisted Fluid Registration Algorithm or SAFIRA,1 which is designed for tracking morphometric differences among populations. To this end, SAFIRA allows the inclusion of statistical priors extracted from the populations being studied as regularizers in the registration. This flexibility and degree of sophistication limit the tool to expert use, even more so considering that SAFIRA was initially implemented in command line mode. Here, we introduce a new, intuitive, easy to use, Matlab-based graphical user interface for SAFIRA's multivariate TBM. The interface also generates different choices for the TBM statistics, including both the traditional univariate statistics on the Jacobian matrix, and comparison of the full deformation tensors.2 This software will be freely disseminated to the neuroimaging research community.

A primer on the study of transitory dynamics in ecological series using the scale-dependent correlation analysis.

PubMed

Rodríguez-Arias, Miquel Angel; Rodó, Xavier

2004-03-01

Here we describe a practical, step-by-step primer to scale-dependent correlation (SDC) analysis. The analysis of transitory processes is an important but often neglected topic in ecological studies because only a few statistical techniques appear to detect temporary features accurately enough. We introduce here the SDC analysis, a statistical and graphical method to study transitory processes at any temporal or spatial scale. SDC analysis, thanks to the combination of conventional procedures and simple well-known statistical techniques, becomes an improved time-domain analogue of wavelet analysis. We use several simple synthetic series to describe the method, a more complex example, full of transitory features, to compare SDC and wavelet analysis, and finally we analyze some selected ecological series to illustrate the methodology. The SDC analysis of time series of copepod abundances in the North Sea indicates that ENSO primarily is the main climatic driver of short-term changes in population dynamics. SDC also uncovers some long-term, unexpected features in the population. Similarly, the SDC analysis of Nicholson's blowflies data locates where the proposed models fail and provides new insights about the mechanism that drives the apparent vanishing of the population cycle during the second half of the series.

Identifying currents in the gene pool for bacterial populations using an integrative approach.

PubMed

Tang, Jing; Hanage, William P; Fraser, Christophe; Corander, Jukka

2009-08-01

The evolution of bacterial populations has recently become considerably better understood due to large-scale sequencing of population samples. It has become clear that DNA sequences from a multitude of genes, as well as a broad sample coverage of a target population, are needed to obtain a relatively unbiased view of its genetic structure and the patterns of ancestry connected to the strains. However, the traditional statistical methods for evolutionary inference, such as phylogenetic analysis, are associated with several difficulties under such an extensive sampling scenario, in particular when a considerable amount of recombination is anticipated to have taken place. To meet the needs of large-scale analyses of population structure for bacteria, we introduce here several statistical tools for the detection and representation of recombination between populations. Also, we introduce a model-based description of the shape of a population in sequence space, in terms of its molecular variability and affinity towards other populations. Extensive real data from the genus Neisseria are utilized to demonstrate the potential of an approach where these population genetic tools are combined with an phylogenetic analysis. The statistical tools introduced here are freely available in BAPS 5.2 software, which can be downloaded from http://web.abo.fi/fak/mnf/mate/jc/software/baps.html.

ISSUES IN THE STATISTICAL ANALYSIS OF SMALL-AREA HEALTH DATA. (R825173)

EPA Science Inventory

The availability of geographically indexed health and population data, with advances in computing, geographical information systems and statistical methodology, have opened the way for serious exploration of small area health statistics based on routine data. Such analyses may be...

Developing Sampling Frame for Case Study: Challenges and Conditions

ERIC Educational Resources Information Center

Ishak, Noriah Mohd; Abu Bakar, Abu Yazid

2014-01-01

Due to statistical analysis, the issue of random sampling is pertinent to any quantitative study. Unlike quantitative study, the elimination of inferential statistical analysis, allows qualitative researchers to be more creative in dealing with sampling issue. Since results from qualitative study cannot be generalized to the bigger population,…

Correcting for population structure and kinship using the linear mixed model: theory and extensions.

PubMed

Hoffman, Gabriel E

2013-01-01

Population structure and kinship are widespread confounding factors in genome-wide association studies (GWAS). It has been standard practice to include principal components of the genotypes in a regression model in order to account for population structure. More recently, the linear mixed model (LMM) has emerged as a powerful method for simultaneously accounting for population structure and kinship. The statistical theory underlying the differences in empirical performance between modeling principal components as fixed versus random effects has not been thoroughly examined. We undertake an analysis to formalize the relationship between these widely used methods and elucidate the statistical properties of each. Moreover, we introduce a new statistic, effective degrees of freedom, that serves as a metric of model complexity and a novel low rank linear mixed model (LRLMM) to learn the dimensionality of the correction for population structure and kinship, and we assess its performance through simulations. A comparison of the results of LRLMM and a standard LMM analysis applied to GWAS data from the Multi-Ethnic Study of Atherosclerosis (MESA) illustrates how our theoretical results translate into empirical properties of the mixed model. Finally, the analysis demonstrates the ability of the LRLMM to substantially boost the strength of an association for HDL cholesterol in Europeans.

The potential of statistical shape modelling for geometric morphometric analysis of human teeth in archaeological research

PubMed Central

Fernee, Christianne; Browne, Martin; Zakrzewski, Sonia

2017-01-01

This paper introduces statistical shape modelling (SSM) for use in osteoarchaeology research. SSM is a full field, multi-material analytical technique, and is presented as a supplementary geometric morphometric (GM) tool. Lower mandibular canines from two archaeological populations and one modern population were sampled, digitised using micro-CT, aligned, registered to a baseline and statistically modelled using principal component analysis (PCA). Sample material properties were incorporated as a binary enamel/dentin parameter. Results were assessed qualitatively and quantitatively using anatomical landmarks. Finally, the technique’s application was demonstrated for inter-sample comparison through analysis of the principal component (PC) weights. It was found that SSM could provide high detail qualitative and quantitative insight with respect to archaeological inter- and intra-sample variability. This technique has value for archaeological, biomechanical and forensic applications including identification, finite element analysis (FEA) and reconstruction from partial datasets. PMID:29216199

PopSc: Computing Toolkit for Basic Statistics of Molecular Population Genetics Simultaneously Implemented in Web-Based Calculator, Python and R

PubMed Central

Huang, Ying; Li, Cao; Liu, Linhai; Jia, Xianbo; Lai, Song-Jia

2016-01-01

Although various computer tools have been elaborately developed to calculate a series of statistics in molecular population genetics for both small- and large-scale DNA data, there is no efficient and easy-to-use toolkit available yet for exclusively focusing on the steps of mathematical calculation. Here, we present PopSc, a bioinformatic toolkit for calculating 45 basic statistics in molecular population genetics, which could be categorized into three classes, including (i) genetic diversity of DNA sequences, (ii) statistical tests for neutral evolution, and (iii) measures of genetic differentiation among populations. In contrast to the existing computer tools, PopSc was designed to directly accept the intermediate metadata, such as allele frequencies, rather than the raw DNA sequences or genotyping results. PopSc is first implemented as the web-based calculator with user-friendly interface, which greatly facilitates the teaching of population genetics in class and also promotes the convenient and straightforward calculation of statistics in research. Additionally, we also provide the Python library and R package of PopSc, which can be flexibly integrated into other advanced bioinformatic packages of population genetics analysis. PMID:27792763

PopSc: Computing Toolkit for Basic Statistics of Molecular Population Genetics Simultaneously Implemented in Web-Based Calculator, Python and R.

PubMed

Chen, Shi-Yi; Deng, Feilong; Huang, Ying; Li, Cao; Liu, Linhai; Jia, Xianbo; Lai, Song-Jia

2016-01-01

Although various computer tools have been elaborately developed to calculate a series of statistics in molecular population genetics for both small- and large-scale DNA data, there is no efficient and easy-to-use toolkit available yet for exclusively focusing on the steps of mathematical calculation. Here, we present PopSc, a bioinformatic toolkit for calculating 45 basic statistics in molecular population genetics, which could be categorized into three classes, including (i) genetic diversity of DNA sequences, (ii) statistical tests for neutral evolution, and (iii) measures of genetic differentiation among populations. In contrast to the existing computer tools, PopSc was designed to directly accept the intermediate metadata, such as allele frequencies, rather than the raw DNA sequences or genotyping results. PopSc is first implemented as the web-based calculator with user-friendly interface, which greatly facilitates the teaching of population genetics in class and also promotes the convenient and straightforward calculation of statistics in research. Additionally, we also provide the Python library and R package of PopSc, which can be flexibly integrated into other advanced bioinformatic packages of population genetics analysis.

Improved score statistics for meta-analysis in single-variant and gene-level association studies.

PubMed

Yang, Jingjing; Chen, Sai; Abecasis, Gonçalo

2018-06-01

Meta-analysis is now an essential tool for genetic association studies, allowing them to combine large studies and greatly accelerating the pace of genetic discovery. Although the standard meta-analysis methods perform equivalently as the more cumbersome joint analysis under ideal settings, they result in substantial power loss under unbalanced settings with various case-control ratios. Here, we investigate the power loss problem by the standard meta-analysis methods for unbalanced studies, and further propose novel meta-analysis methods performing equivalently to the joint analysis under both balanced and unbalanced settings. We derive improved meta-score-statistics that can accurately approximate the joint-score-statistics with combined individual-level data, for both linear and logistic regression models, with and without covariates. In addition, we propose a novel approach to adjust for population stratification by correcting for known population structures through minor allele frequencies. In the simulated gene-level association studies under unbalanced settings, our method recovered up to 85% power loss caused by the standard methods. We further showed the power gain of our methods in gene-level tests with 26 unbalanced studies of age-related macular degeneration . In addition, we took the meta-analysis of three unbalanced studies of type 2 diabetes as an example to discuss the challenges of meta-analyzing multi-ethnic samples. In summary, our improved meta-score-statistics with corrections for population stratification can be used to construct both single-variant and gene-level association studies, providing a useful framework for ensuring well-powered, convenient, cross-study analyses. © 2018 WILEY PERIODICALS, INC.

Study design and statistical analysis of data in human population studies with the micronucleus assay.

PubMed

Ceppi, Marcello; Gallo, Fabio; Bonassi, Stefano

2011-01-01

The most common study design performed in population studies based on the micronucleus (MN) assay, is the cross-sectional study, which is largely performed to evaluate the DNA damaging effects of exposure to genotoxic agents in the workplace, in the environment, as well as from diet or lifestyle factors. Sample size is still a critical issue in the design of MN studies since most recent studies considering gene-environment interaction, often require a sample size of several hundred subjects, which is in many cases difficult to achieve. The control of confounding is another major threat to the validity of causal inference. The most popular confounders considered in population studies using MN are age, gender and smoking habit. Extensive attention is given to the assessment of effect modification, given the increasing inclusion of biomarkers of genetic susceptibility in the study design. Selected issues concerning the statistical treatment of data have been addressed in this mini-review, starting from data description, which is a critical step of statistical analysis, since it allows to detect possible errors in the dataset to be analysed and to check the validity of assumptions required for more complex analyses. Basic issues dealing with statistical analysis of biomarkers are extensively evaluated, including methods to explore the dose-response relationship among two continuous variables and inferential analysis. A critical approach to the use of parametric and non-parametric methods is presented, before addressing the issue of most suitable multivariate models to fit MN data. In the last decade, the quality of statistical analysis of MN data has certainly evolved, although even nowadays only a small number of studies apply the Poisson model, which is the most suitable method for the analysis of MN data.

ANALYSIS TO ACCOUNT FOR SMALL AGE RANGE CATEGORIES IN DISTRIBUTIONS OF WATER CONSUMPTION AND BODY WEIGHT IN THE U.S. USING CSFII DATA

EPA Science Inventory

Statistical population based estimates of water ingestion play a vital role in many types of exposure and risk analysis. A significant large scale analysis of water ingestion by the population of the United States was recently completed and is documented in the report titled ...

Signatures of criticality arise from random subsampling in simple population models.

PubMed

Nonnenmacher, Marcel; Behrens, Christian; Berens, Philipp; Bethge, Matthias; Macke, Jakob H

2017-10-01

The rise of large-scale recordings of neuronal activity has fueled the hope to gain new insights into the collective activity of neural ensembles. How can one link the statistics of neural population activity to underlying principles and theories? One attempt to interpret such data builds upon analogies to the behaviour of collective systems in statistical physics. Divergence of the specific heat-a measure of population statistics derived from thermodynamics-has been used to suggest that neural populations are optimized to operate at a "critical point". However, these findings have been challenged by theoretical studies which have shown that common inputs can lead to diverging specific heat. Here, we connect "signatures of criticality", and in particular the divergence of specific heat, back to statistics of neural population activity commonly studied in neural coding: firing rates and pairwise correlations. We show that the specific heat diverges whenever the average correlation strength does not depend on population size. This is necessarily true when data with correlations is randomly subsampled during the analysis process, irrespective of the detailed structure or origin of correlations. We also show how the characteristic shape of specific heat capacity curves depends on firing rates and correlations, using both analytically tractable models and numerical simulations of a canonical feed-forward population model. To analyze these simulations, we develop efficient methods for characterizing large-scale neural population activity with maximum entropy models. We find that, consistent with experimental findings, increases in firing rates and correlation directly lead to more pronounced signatures. Thus, previous reports of thermodynamical criticality in neural populations based on the analysis of specific heat can be explained by average firing rates and correlations, and are not indicative of an optimized coding strategy. We conclude that a reliable interpretation of statistical tests for theories of neural coding is possible only in reference to relevant ground-truth models.

A spatial analysis of population dynamics and climate change in Africa: potential vulnerability hot spots emerge where precipitation declines and demographic pressures coincide

USGS Publications Warehouse

López-Carr, David; Pricope, Narcisa G.; Aukema, Juliann E.; Jankowska, Marta M.; Funk, Christopher C.; Husak, Gregory J.; Michaelsen, Joel C.

2014-01-01

We present an integrative measure of exposure and sensitivity components of vulnerability to climatic and demographic change for the African continent in order to identify “hot spots” of high potential population vulnerability. Getis-Ord Gi* spatial clustering analyses reveal statistically significant locations of spatio-temporal precipitation decline coinciding with high population density and increase. Statistically significant areas are evident, particularly across central, southern, and eastern Africa. The highly populated Lake Victoria basin emerges as a particularly salient hot spot. People located in the regions highlighted in this analysis suffer exceptionally high exposure to negative climate change impacts (as populations increase on lands with decreasing rainfall). Results may help inform further hot spot mapping and related research on demographic vulnerabilities to climate change. Results may also inform more suitable geographical targeting of policy interventions across the continent.

Improving Student Understanding of Spatial Ecology Statistics

ERIC Educational Resources Information Center

Hopkins, Robert, II; Alberts, Halley

2015-01-01

This activity is designed as a primer to teaching population dispersion analysis. The aim is to help improve students' spatial thinking and their understanding of how spatial statistic equations work. Students use simulated data to develop their own statistic and apply that equation to experimental behavioral data for Gambusia affinis (western…

[A comparison of convenience sampling and purposive sampling].

PubMed

Suen, Lee-Jen Wu; Huang, Hui-Man; Lee, Hao-Hsien

2014-06-01

Convenience sampling and purposive sampling are two different sampling methods. This article first explains sampling terms such as target population, accessible population, simple random sampling, intended sample, actual sample, and statistical power analysis. These terms are then used to explain the difference between "convenience sampling" and purposive sampling." Convenience sampling is a non-probabilistic sampling technique applicable to qualitative or quantitative studies, although it is most frequently used in quantitative studies. In convenience samples, subjects more readily accessible to the researcher are more likely to be included. Thus, in quantitative studies, opportunity to participate is not equal for all qualified individuals in the target population and study results are not necessarily generalizable to this population. As in all quantitative studies, increasing the sample size increases the statistical power of the convenience sample. In contrast, purposive sampling is typically used in qualitative studies. Researchers who use this technique carefully select subjects based on study purpose with the expectation that each participant will provide unique and rich information of value to the study. As a result, members of the accessible population are not interchangeable and sample size is determined by data saturation not by statistical power analysis.

Evaluation of the ecological relevance of mysid toxicity tests using population modeling techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuhn-Hines, A.; Munns, W.R. Jr.; Lussier, S.

1995-12-31

A number of acute and chronic bioassay statistics are used to evaluate the toxicity and risks of chemical stressors to the mysid shrimp, Mysidopsis bahia. These include LC{sub 50}S from acute tests, NOECs from 7-day and life-cycle tests, and the US EPA Water Quality Criteria Criterion Continuous Concentrations (CCC). Because these statistics are generated from endpoints which focus upon the responses of individual organisms, their relationships to significant effects at higher levels of ecological organization are unknown. This study was conducted to evaluate the quantitative relationships between toxicity test statistics and a concentration-based statistic derived from exposure-response models describing populationmore » growth rate ({lambda}) to stressor concentration. This statistic, C{sup {sm_bullet}} (concentration where {lambda} = I, zero population growth) describes the concentration above which mysid populations are projected to decline in abundance as determined using population modeling techniques. An analysis of M. bahia responses to 9 metals and 9 organic contaminants indicated the NOEC from life-cycle tests to be the best predictor of C{sup {sm_bullet}}, although the acute LC{sub 50} predicted population-level response surprisingly well. These analyses provide useful information regarding uncertainties of extrapolation among test statistics in assessments of ecological risk.« less

A novel complete-case analysis to determine statistical significance between treatments in an intention-to-treat population of randomized clinical trials involving missing data.

PubMed

Liu, Wei; Ding, Jinhui

2018-04-01

The application of the principle of the intention-to-treat (ITT) to the analysis of clinical trials is challenged in the presence of missing outcome data. The consequences of stopping an assigned treatment in a withdrawn subject are unknown. It is difficult to make a single assumption about missing mechanisms for all clinical trials because there are complicated reactions in the human body to drugs due to the presence of complex biological networks, leading to data missing randomly or non-randomly. Currently there is no statistical method that can tell whether a difference between two treatments in the ITT population of a randomized clinical trial with missing data is significant at a pre-specified level. Making no assumptions about the missing mechanisms, we propose a generalized complete-case (GCC) analysis based on the data of completers. An evaluation of the impact of missing data on the ITT analysis reveals that a statistically significant GCC result implies a significant treatment effect in the ITT population at a pre-specified significance level unless, relative to the comparator, the test drug is poisonous to the non-completers as documented in their medical records. Applications of the GCC analysis are illustrated using literature data, and its properties and limits are discussed.

Phylogeography, intraspecific structure and sex-biased dispersal of Dall's porpoise, Phocoenoides dalli, revealed by mitochondrial and microsatellite DNA analyses.

PubMed

Escorza-Treviño, S; Dizon, A E

2000-08-01

Mitochondrial DNA (mtDNA) control-region sequences and microsatellite loci length polymorphisms were used to estimate phylogeographical patterns (historical patterns underlying contemporary distribution), intraspecific population structure and gender-biased dispersal of Phocoenoides dalli dalli across its entire range. One-hundred and thirteen animals from several geographical strata were sequenced over 379 bp of mtDNA, resulting in 58 mtDNA haplotypes. Analysis using F(ST) values (based on haplotype frequencies) and phi(ST) values (based on frequencies and genetic distances between haplotypes) yielded statistically significant separation (bootstrap values P < 0.05) among most of the stocks currently used for management purposes. A minimum spanning network of haplotypes showed two very distinctive clusters, differentially occupied by western and eastern populations, with some common widespread haplotypes. This suggests some degree of phyletic radiation from west to east, superimposed on gene flow. Highly male-biased migration was detected for several population comparisons. Nuclear microsatellite DNA markers (119 individuals and six loci) provided additional support for population subdivision and gender-biased dispersal detected in the mtDNA sequences. Analysis using F(ST) values (based on allelic frequencies) yielded statistically significant separation between some, but not all, populations distinguished by mtDNA analysis. R(ST) values (based on frequencies of and genetic distance between alleles) showed no statistically significant subdivision. Again, highly male-biased dispersal was detected for all population comparisons, suggesting, together with morphological and reproductive data, the existence of sexual selection. Our molecular results argue for nine distinct dalli-type populations that should be treated as separate units for management purposes.

The Importance of Teaching Power in Statistical Hypothesis Testing

ERIC Educational Resources Information Center

Olinsky, Alan; Schumacher, Phyllis; Quinn, John

2012-01-01

In this paper, we discuss the importance of teaching power considerations in statistical hypothesis testing. Statistical power analysis determines the ability of a study to detect a meaningful effect size, where the effect size is the difference between the hypothesized value of the population parameter under the null hypothesis and the true value…

Estimating an Effect Size in One-Way Multivariate Analysis of Variance (MANOVA)

ERIC Educational Resources Information Center

Steyn, H. S., Jr.; Ellis, S. M.

2009-01-01

When two or more univariate population means are compared, the proportion of variation in the dependent variable accounted for by population group membership is eta-squared. This effect size can be generalized by using multivariate measures of association, based on the multivariate analysis of variance (MANOVA) statistics, to establish whether…

Introducing Undergraduate Students to Metabolomics Using a NMR-Based Analysis of Coffee Beans

ERIC Educational Resources Information Center

Sandusky, Peter Olaf

2017-01-01

Metabolomics applies multivariate statistical analysis to sets of high-resolution spectra taken over a population of biologically derived samples. The objective is to distinguish subpopulations within the overall sample population, and possibly also to identify biomarkers. While metabolomics has become part of the standard analytical toolbox in…

Profile of Undergraduates in U.S. Postsecondary Education Institutions, 2003-04: With a Special Analysis of Community College Students. Statistical Analysis Report. NCES 2006-184

ERIC Educational Resources Information Center

Horn, Laura; Nevill, Stephanie; Griffith, James

2006-01-01

This report is the fifth in a series of reports that provide a statistical snapshot of the undergraduate population. The reports accompany the newly released data from the National Postsecondary Student Aid Study (NPSAS), and each one includes a focused analysis on a particular topic. This report focuses on community college students, who…

Mapping cell populations in flow cytometry data for cross‐sample comparison using the Friedman–Rafsky test statistic as a distance measure

PubMed Central

Hsiao, Chiaowen; Liu, Mengya; Stanton, Rick; McGee, Monnie; Qian, Yu

2015-01-01

Abstract Flow cytometry (FCM) is a fluorescence‐based single‐cell experimental technology that is routinely applied in biomedical research for identifying cellular biomarkers of normal physiological responses and abnormal disease states. While many computational methods have been developed that focus on identifying cell populations in individual FCM samples, very few have addressed how the identified cell populations can be matched across samples for comparative analysis. This article presents FlowMap‐FR, a novel method for cell population mapping across FCM samples. FlowMap‐FR is based on the Friedman–Rafsky nonparametric test statistic (FR statistic), which quantifies the equivalence of multivariate distributions. As applied to FCM data by FlowMap‐FR, the FR statistic objectively quantifies the similarity between cell populations based on the shapes, sizes, and positions of fluorescence data distributions in the multidimensional feature space. To test and evaluate the performance of FlowMap‐FR, we simulated the kinds of biological and technical sample variations that are commonly observed in FCM data. The results show that FlowMap‐FR is able to effectively identify equivalent cell populations between samples under scenarios of proportion differences and modest position shifts. As a statistical test, FlowMap‐FR can be used to determine whether the expression of a cellular marker is statistically different between two cell populations, suggesting candidates for new cellular phenotypes by providing an objective statistical measure. In addition, FlowMap‐FR can indicate situations in which inappropriate splitting or merging of cell populations has occurred during gating procedures. We compared the FR statistic with the symmetric version of Kullback–Leibler divergence measure used in a previous population matching method with both simulated and real data. The FR statistic outperforms the symmetric version of KL‐distance in distinguishing equivalent from nonequivalent cell populations. FlowMap‐FR was also employed as a distance metric to match cell populations delineated by manual gating across 30 FCM samples from a benchmark FlowCAP data set. An F‐measure of 0.88 was obtained, indicating high precision and recall of the FR‐based population matching results. FlowMap‐FR has been implemented as a standalone R/Bioconductor package so that it can be easily incorporated into current FCM data analytical workflows. © 2015 International Society for Advancement of Cytometry PMID:26274018

Mapping cell populations in flow cytometry data for cross-sample comparison using the Friedman-Rafsky test statistic as a distance measure.

PubMed

Hsiao, Chiaowen; Liu, Mengya; Stanton, Rick; McGee, Monnie; Qian, Yu; Scheuermann, Richard H

2016-01-01

Flow cytometry (FCM) is a fluorescence-based single-cell experimental technology that is routinely applied in biomedical research for identifying cellular biomarkers of normal physiological responses and abnormal disease states. While many computational methods have been developed that focus on identifying cell populations in individual FCM samples, very few have addressed how the identified cell populations can be matched across samples for comparative analysis. This article presents FlowMap-FR, a novel method for cell population mapping across FCM samples. FlowMap-FR is based on the Friedman-Rafsky nonparametric test statistic (FR statistic), which quantifies the equivalence of multivariate distributions. As applied to FCM data by FlowMap-FR, the FR statistic objectively quantifies the similarity between cell populations based on the shapes, sizes, and positions of fluorescence data distributions in the multidimensional feature space. To test and evaluate the performance of FlowMap-FR, we simulated the kinds of biological and technical sample variations that are commonly observed in FCM data. The results show that FlowMap-FR is able to effectively identify equivalent cell populations between samples under scenarios of proportion differences and modest position shifts. As a statistical test, FlowMap-FR can be used to determine whether the expression of a cellular marker is statistically different between two cell populations, suggesting candidates for new cellular phenotypes by providing an objective statistical measure. In addition, FlowMap-FR can indicate situations in which inappropriate splitting or merging of cell populations has occurred during gating procedures. We compared the FR statistic with the symmetric version of Kullback-Leibler divergence measure used in a previous population matching method with both simulated and real data. The FR statistic outperforms the symmetric version of KL-distance in distinguishing equivalent from nonequivalent cell populations. FlowMap-FR was also employed as a distance metric to match cell populations delineated by manual gating across 30 FCM samples from a benchmark FlowCAP data set. An F-measure of 0.88 was obtained, indicating high precision and recall of the FR-based population matching results. FlowMap-FR has been implemented as a standalone R/Bioconductor package so that it can be easily incorporated into current FCM data analytical workflows. © The Authors. Published by Wiley Periodicals, Inc. on behalf of ISAC.

What's Hot and What's Not: Multivariate Statistical Analysis of Ten Labile Trace Elements in H-Chondrite Population Pairs

NASA Astrophysics Data System (ADS)

Wolf, S. F.; Lipschutz, M. E.

1993-07-01

Dodd et al. [1] found that, from their circumstances of fall, 17 H chondrites ("H Cluster 1") which fell in May, from 1855 to 1895, are distinguishable from other H chondrite falls and apparently derive from a co-orbital stream of meteoroids. From data for 10 moderately to highly labile trace elements (Rb, Ag, Se, Cs, Te, Zn, Cd, Bi, Tl, In), they used two multivariate statistical techniques--linear discriminant analysis and logistic regression--to demonstrate that 1. 13 H Cluster 1 chondrites are compositionally distinguishable from 45 other H chondrite falls, probably because of differences in thermal histories of the meteorites' parent materials; 2. The reality of the compositional differences between the populations of falls are beyond any reasonable statistical doubt. 3. The compositional differences are inconsistent with the notion that the results reflect analytical bias. We have used these techniques to assess analogous data for various H chondrite populations [2-4] with results that are listed in Table 1. These data indicate that 1. There is no statistical reason to believe that random populations from Victoria Land, Antarctica, differ compositionally from each other. 2. There is significant statistical reason to believe that the H chondrite population recovered from Victoria Land, Antarctica, differs compositionally from that from Queen Maud Land, Antarctica, and from falls. 3. There is no reason to believe that the H chondrite population recovered from Queen Maud Land, Antarctica, differs compositionally from falls. 4. These observations can be made either by data obtained by one analyst or several. These results, coupled with earlier ones [5], demonstrate that trivial explanations cannot explain compositional differences involving labile trace elements in pairs of H chondrite populations. These differences must then reflect differences of preterrestrial thermal histories of the meteorites' parent materials. Acceptance of these differences as preterrestrial has led to predictions subsequently verified by others (meteoroid and asteroid stream discoveries, differencesin thermoluminescence or TL). We predict that a TL difference will be seen between the populations of falls defined by Dodd et al. [1]. References: [1] Dodd R. T. et al. (1993) JGR, submitted. [2] Lingner D. W. et al. (1987) GCA, 51, 727-739. [3] Dennison J. E. and Lipschutz M. E. (1987) GCA, 51, 741-754. [4] Wolf S. F. and Lipschutz M. E. (1993) in Advances in Analytical Geochemistry (M. Hyman and M. Rowe, eds.), in press. [5] Wang M.-S. et al. (1992) Meteoritics, 27, 303. [6] Lipschutz M. E. and Samuels S. M. (1991) GCA, 55, 19-47. Table 1, which appears in the hard copy, shows a multivariate statistical analysis of H chondrite population pairs using 10 labile trace elements (number of meteorites in population in parentheses).

The Other Twenty Percent: A Statistical Analysis of Poverty in the South.

ERIC Educational Resources Information Center

MacLachlan, Gretchen

Of the 27 million poor people in the United States in 1970, 10 million lived in the 11 Southern states. This was 38% of the nation's poverty population, making the South's poverty rate twice that of the remaining 39 states. This study, essentially a statistical analysis of regional poverty data derived from the 1970 Census, identifies the South's…

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

PubMed

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

2015-08-01

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

Data Analysis and Statistical Methods for the Assessment and Interpretation of Geochronologic Data

NASA Astrophysics Data System (ADS)

Reno, B. L.; Brown, M.; Piccoli, P. M.

2007-12-01

Ages are traditionally reported as a weighted mean with an uncertainty based on least squares analysis of analytical error on individual dates. This method does not take into account geological uncertainties, and cannot accommodate asymmetries in the data. In most instances, this method will understate uncertainty on a given age, which may lead to over interpretation of age data. Geologic uncertainty is difficult to quantify, but is typically greater than analytical uncertainty. These factors make traditional statistical approaches inadequate to fully evaluate geochronologic data. We propose a protocol to assess populations within multi-event datasets and to calculate age and uncertainty from each population of dates interpreted to represent a single geologic event using robust and resistant statistical methods. To assess whether populations thought to represent different events are statistically separate exploratory data analysis is undertaken using a box plot, where the range of the data is represented by a 'box' of length given by the interquartile range, divided at the median of the data, with 'whiskers' that extend to the furthest datapoint that lies within 1.5 times the interquartile range beyond the box. If the boxes representing the populations do not overlap, they are interpreted to represent statistically different sets of dates. Ages are calculated from statistically distinct populations using a robust tool such as the tanh method of Kelsey et al. (2003, CMP, 146, 326-340), which is insensitive to any assumptions about the underlying probability distribution from which the data are drawn. Therefore, this method takes into account the full range of data, and is not drastically affected by outliers. The interquartile range of each population of dates (the interquartile range) gives a first pass at expressing uncertainty, which accommodates asymmetry in the dataset; outliers have a minor affect on the uncertainty. To better quantify the uncertainty, a resistant tool that is insensitive to local misbehavior of data is preferred, such as the normalized median absolute deviations proposed by Powell et al. (2002, Chem Geol, 185, 191-204). We illustrate the method using a dataset of 152 monazite dates determined using EPMA chemical data from a single sample from the Neoproterozoic Brasília Belt, Brazil. Results are compared with ages and uncertainties calculated using traditional methods to demonstrate the differences. The dataset was manually culled into three populations representing discrete compositional domains within chemically-zoned monazite grains. The weighted mean ages and least squares uncertainties for these populations are 633±6 (2σ) Ma for a core domain, 614±5 (2σ) Ma for an intermediate domain and 595±6 (2σ) Ma for a rim domain. Probability distribution plots indicate asymmetric distributions of all populations, which cannot be accounted for with traditional statistical tools. These three domains record distinct ages outside the interquartile range for each population of dates, with the core domain lying in the subrange 642-624 Ma, the intermediate domain 617-609 Ma and the rim domain 606-589 Ma. The tanh estimator yields ages of 631±7 (2σ) for the core domain, 616±7 (2σ) for the intermediate domain and 601±8 (2σ) for the rim domain. Whereas the uncertainties derived using a resistant statistical tool are larger than those derived from traditional statistical tools, the method yields more realistic uncertainties that better address the spread in the dataset and account for asymmetry in the data.

A Third Moment Adjusted Test Statistic for Small Sample Factor Analysis.

PubMed

Lin, Johnny; Bentler, Peter M

2012-01-01

Goodness of fit testing in factor analysis is based on the assumption that the test statistic is asymptotically chi-square; but this property may not hold in small samples even when the factors and errors are normally distributed in the population. Robust methods such as Browne's asymptotically distribution-free method and Satorra Bentler's mean scaling statistic were developed under the presumption of non-normality in the factors and errors. This paper finds new application to the case where factors and errors are normally distributed in the population but the skewness of the obtained test statistic is still high due to sampling error in the observed indicators. An extension of Satorra Bentler's statistic is proposed that not only scales the mean but also adjusts the degrees of freedom based on the skewness of the obtained test statistic in order to improve its robustness under small samples. A simple simulation study shows that this third moment adjusted statistic asymptotically performs on par with previously proposed methods, and at a very small sample size offers superior Type I error rates under a properly specified model. Data from Mardia, Kent and Bibby's study of students tested for their ability in five content areas that were either open or closed book were used to illustrate the real-world performance of this statistic.

A statistical approach to quasi-extinction forecasting.

PubMed

Holmes, Elizabeth Eli; Sabo, John L; Viscido, Steven Vincent; Fagan, William Fredric

2007-12-01

Forecasting population decline to a certain critical threshold (the quasi-extinction risk) is one of the central objectives of population viability analysis (PVA), and such predictions figure prominently in the decisions of major conservation organizations. In this paper, we argue that accurate forecasting of a population's quasi-extinction risk does not necessarily require knowledge of the underlying biological mechanisms. Because of the stochastic and multiplicative nature of population growth, the ensemble behaviour of population trajectories converges to common statistical forms across a wide variety of stochastic population processes. This paper provides a theoretical basis for this argument. We show that the quasi-extinction surfaces of a variety of complex stochastic population processes (including age-structured, density-dependent and spatially structured populations) can be modelled by a simple stochastic approximation: the stochastic exponential growth process overlaid with Gaussian errors. Using simulated and real data, we show that this model can be estimated with 20-30 years of data and can provide relatively unbiased quasi-extinction risk with confidence intervals considerably smaller than (0,1). This was found to be true even for simulated data derived from some of the noisiest population processes (density-dependent feedback, species interactions and strong age-structure cycling). A key advantage of statistical models is that their parameters and the uncertainty of those parameters can be estimated from time series data using standard statistical methods. In contrast for most species of conservation concern, biologically realistic models must often be specified rather than estimated because of the limited data available for all the various parameters. Biologically realistic models will always have a prominent place in PVA for evaluating specific management options which affect a single segment of a population, a single demographic rate, or different geographic areas. However, for forecasting quasi-extinction risk, statistical models that are based on the convergent statistical properties of population processes offer many advantages over biologically realistic models.

Comparison of diagnostic capability of macular ganglion cell complex and retinal nerve fiber layer among primary open angle glaucoma, ocular hypertension, and normal population using Fourier-domain optical coherence tomography and determining their functional correlation in Indian population

PubMed Central

Barua, Nabanita; Sitaraman, Chitra; Goel, Sonu; Chakraborti, Chandana; Mukherjee, Sonai; Parashar, Hemandra

2016-01-01

Context: Analysis of diagnostic ability of macular ganglionic cell complex and retinal nerve fiber layer (RNFL) in glaucoma. Aim: To correlate functional and structural parameters and comparing predictive value of each of the structural parameters using Fourier-domain (FD) optical coherence tomography (OCT) among primary open angle glaucoma (POAG) and ocular hypertension (OHT) versus normal population. Setting and Design: Single centric, cross-sectional study done in 234 eyes. Materials and Methods: Patients were enrolled in three groups: POAG, ocular hypertensive and normal (40 patients in each group). After comprehensive ophthalmological examination, patients underwent standard automated perimetry and FD-OCT scan in optic nerve head and ganglion cell mode. The relationship was assessed by correlating ganglion cell complex (GCC) parameters with mean deviation. Results were compared with RNFL parameters. Statistical Analysis: Data were analyzed with SPSS, analysis of variance, t-test, Pearson's coefficient, and receiver operating curve. Results: All parameters showed strong correlation with visual field (P < 0.001). Inferior GCC had highest area under curve (AUC) for detecting glaucoma (0.827) in POAG from normal population. However, the difference was not statistically significant (P > 0.5) when compared with other parameters. None of the parameters showed significant diagnostic capability to detect OHT from normal population. In diagnosing early glaucoma from OHT and normal population, only inferior GCC had statistically significant AUC value (0.715). Conclusion: In this study, GCC and RNFL parameters showed equal predictive capability in perimetric versus normal group. In early stage, inferior GCC was the best parameter. In OHT population, single day cross-sectional imaging was not valuable. PMID:27221682

A New Method for Estimating the Effective Population Size from Allele Frequency Changes

PubMed Central

Pollak, Edward

1983-01-01

A new procedure is proposed for estimating the effective population size, given that information is available on changes in frequencies of the alleles at one or more independently segregating loci and the population is observed at two or more separate times. Approximate expressions are obtained for the variances of the new statistic, as well as others, also based on allele frequency changes, that have been discussed in the literature. This analysis indicates that the new statistic will generally have a smaller variance than the others. Estimates of effective population sizes and of the standard errors of the estimates are computed for data on two fly populations that have been discussed in earlier papers. In both cases, there is evidence that the effective population size is very much smaller than the minimum census size of the population. PMID:17246147

Nonlinear Analysis of Time Series in Genome-Wide Linkage Disequilibrium Data

NASA Astrophysics Data System (ADS)

Hernández-Lemus, Enrique; Estrada-Gil, Jesús K.; Silva-Zolezzi, Irma; Fernández-López, J. Carlos; Hidalgo-Miranda, Alfredo; Jiménez-Sánchez, Gerardo

2008-02-01

The statistical study of large scale genomic data has turned out to be a very important tool in population genetics. Quantitative methods are essential to understand and implement association studies in the biomedical and health sciences. Nevertheless, the characterization of recently admixed populations has been an elusive problem due to the presence of a number of complex phenomena. For example, linkage disequilibrium structures are thought to be more complex than their non-recently admixed population counterparts, presenting the so-called ancestry blocks, admixed regions that are not yet smoothed by the effect of genetic recombination. In order to distinguish characteristic features for various populations we have implemented several methods, some of them borrowed or adapted from the analysis of nonlinear time series in statistical physics and quantitative physiology. We calculate the main fractal dimensions (Kolmogorov's capacity, information dimension and correlation dimension, usually named, D0, D1 and D2). We also have made detrended fluctuation analysis and information based similarity index calculations for the probability distribution of correlations of linkage disequilibrium coefficient of six recently admixed (mestizo) populations within the Mexican Genome Diversity Project [1] and for the non-recently admixed populations in the International HapMap Project [2]. Nonlinear correlations showed up as a consequence of internal structure within the haplotype distributions. The analysis of these correlations as well as the scope and limitations of these procedures within the biomedical sciences are discussed.

Methods for Assessment of Memory Reactivation.

PubMed

Liu, Shizhao; Grosmark, Andres D; Chen, Zhe

2018-04-13

It has been suggested that reactivation of previously acquired experiences or stored information in declarative memories in the hippocampus and neocortex contributes to memory consolidation and learning. Understanding memory consolidation depends crucially on the development of robust statistical methods for assessing memory reactivation. To date, several statistical methods have seen established for assessing memory reactivation based on bursts of ensemble neural spike activity during offline states. Using population-decoding methods, we propose a new statistical metric, the weighted distance correlation, to assess hippocampal memory reactivation (i.e., spatial memory replay) during quiet wakefulness and slow-wave sleep. The new metric can be combined with an unsupervised population decoding analysis, which is invariant to latent state labeling and allows us to detect statistical dependency beyond linearity in memory traces. We validate the new metric using two rat hippocampal recordings in spatial navigation tasks. Our proposed analysis framework may have a broader impact on assessing memory reactivations in other brain regions under different behavioral tasks.

Adaptation to local ultraviolet radiation conditions among neighbouring Daphnia populations

PubMed Central

Miner, Brooks E.; Kerr, Benjamin

2011-01-01

Understanding the historical processes that generated current patterns of phenotypic diversity in nature is particularly challenging in subdivided populations. Populations often exhibit heritable genetic differences that correlate with environmental variables, but the non-independence among neighbouring populations complicates statistical inference of adaptation. To understand the relative influence of adaptive and non-adaptive processes in generating phenotypes requires joint evaluation of genetic and phenotypic divergence in an integrated and statistically appropriate analysis. We investigated phenotypic divergence, population-genetic structure and potential fitness trade-offs in populations of Daphnia melanica inhabiting neighbouring subalpine ponds of widely differing transparency to ultraviolet radiation (UVR). Using a combination of experimental, population-genetic and statistical techniques, we separated the effects of shared population ancestry and environmental variables in predicting phenotypic divergence among populations. We found that native water transparency significantly predicted divergence in phenotypes among populations even after accounting for significant population structure. This result demonstrates that environmental factors such as UVR can at least partially account for phenotypic divergence. However, a lack of evidence for a hypothesized trade-off between UVR tolerance and growth rates in the absence of UVR prevents us from ruling out the possibility that non-adaptive processes are partially responsible for phenotypic differentiation in this system. PMID:20943691

Artificial neural network models for prediction of cardiovascular autonomic dysfunction in general Chinese population

PubMed Central

2013-01-01

Background The present study aimed to develop an artificial neural network (ANN) based prediction model for cardiovascular autonomic (CA) dysfunction in the general population. Methods We analyzed a previous dataset based on a population sample consisted of 2,092 individuals aged 30–80 years. The prediction models were derived from an exploratory set using ANN analysis. Performances of these prediction models were evaluated in the validation set. Results Univariate analysis indicated that 14 risk factors showed statistically significant association with CA dysfunction (P < 0.05). The mean area under the receiver-operating curve was 0.762 (95% CI 0.732–0.793) for prediction model developed using ANN analysis. The mean sensitivity, specificity, positive and negative predictive values were similar in the prediction models was 0.751, 0.665, 0.330 and 0.924, respectively. All HL statistics were less than 15.0. Conclusion ANN is an effective tool for developing prediction models with high value for predicting CA dysfunction among the general population. PMID:23902963

Statistical tools for analysis and modeling of cosmic populations and astronomical time series: CUDAHM and TSE

NASA Astrophysics Data System (ADS)

Loredo, Thomas; Budavari, Tamas; Scargle, Jeffrey D.

2018-01-01

This presentation provides an overview of open-source software packages addressing two challenging classes of astrostatistics problems. (1) CUDAHM is a C++ framework for hierarchical Bayesian modeling of cosmic populations, leveraging graphics processing units (GPUs) to enable applying this computationally challenging paradigm to large datasets. CUDAHM is motivated by measurement error problems in astronomy, where density estimation and linear and nonlinear regression must be addressed for populations of thousands to millions of objects whose features are measured with possibly complex uncertainties, potentially including selection effects. An example calculation demonstrates accurate GPU-accelerated luminosity function estimation for simulated populations of $10^6$ objects in about two hours using a single NVIDIA Tesla K40c GPU. (2) Time Series Explorer (TSE) is a collection of software in Python and MATLAB for exploratory analysis and statistical modeling of astronomical time series. It comprises a library of stand-alone functions and classes, as well as an application environment for interactive exploration of times series data. The presentation will summarize key capabilities of this emerging project, including new algorithms for analysis of irregularly-sampled time series.

[The application of the multidimensional statistical methods in the evaluation of the influence of atmospheric pollution on the population's health].

PubMed

Surzhikov, V D; Surzhikov, D V

2014-01-01

The search and measurement of causal relationships between exposure to air pollution and health state of the population is based on the system analysis and risk assessment to improve the quality of research. With this purpose there is applied the modern statistical analysis with the use of criteria of independence, principal component analysis and discriminate function analysis. As a result of analysis out of all atmospheric pollutants there were separated four main components: for diseases of the circulatory system main principal component is implied with concentrations of suspended solids, nitrogen dioxide, carbon monoxide, hydrogen fluoride, for the respiratory diseases the main c principal component is closely associated with suspended solids, sulfur dioxide and nitrogen dioxide, charcoal black. The discriminant function was shown to be used as a measure of the level of air pollution.

Analysis of the HLA population data (AHPD) submitted to the 15th International Histocompatibility/Immunogenetics Workshop by using the Gene[rate] computer tools accommodating ambiguous data (AHPD project report).

PubMed

Nunes, J M; Riccio, M E; Buhler, S; Di, D; Currat, M; Ries, F; Almada, A J; Benhamamouch, S; Benitez, O; Canossi, A; Fadhlaoui-Zid, K; Fischer, G; Kervaire, B; Loiseau, P; de Oliveira, D C M; Papasteriades, C; Piancatelli, D; Rahal, M; Richard, L; Romero, M; Rousseau, J; Spiroski, M; Sulcebe, G; Middleton, D; Tiercy, J-M; Sanchez-Mazas, A

2010-07-01

During the 15th International Histocompatibility and Immunogenetics Workshop (IHIWS), 14 human leukocyte antigen (HLA) laboratories participated in the Analysis of HLA Population Data (AHPD) project where 18 new population samples were analyzed statistically and compared with data available from previous workshops. To that aim, an original methodology was developed and used (i) to estimate frequencies by taking into account ambiguous genotypic data, (ii) to test for Hardy-Weinberg equilibrium (HWE) by using a nested likelihood ratio test involving a parameter accounting for HWE deviations, (iii) to test for selective neutrality by using a resampling algorithm, and (iv) to provide explicit graphical representations including allele frequencies and basic statistics for each series of data. A total of 66 data series (1-7 loci per population) were analyzed with this standard approach. Frequency estimates were compliant with HWE in all but one population of mixed stem cell donors. Neutrality testing confirmed the observation of heterozygote excess at all HLA loci, although a significant deviation was established in only a few cases. Population comparisons showed that HLA genetic patterns were mostly shaped by geographic and/or linguistic differentiations in Africa and Europe, but not in America where both genetic drift in isolated populations and gene flow in admixed populations led to a more complex genetic structure. Overall, a fruitful collaboration between HLA typing laboratories and population geneticists allowed finding useful solutions to the problem of estimating gene frequencies and testing basic population diversity statistics on highly complex HLA data (high numbers of alleles and ambiguities), with promising applications in either anthropological, epidemiological, or transplantation studies.

Fully Bayesian tests of neutrality using genealogical summary statistics.

PubMed

Drummond, Alexei J; Suchard, Marc A

2008-10-31

Many data summary statistics have been developed to detect departures from neutral expectations of evolutionary models. However questions about the neutrality of the evolution of genetic loci within natural populations remain difficult to assess. One critical cause of this difficulty is that most methods for testing neutrality make simplifying assumptions simultaneously about the mutational model and the population size model. Consequentially, rejecting the null hypothesis of neutrality under these methods could result from violations of either or both assumptions, making interpretation troublesome. Here we harness posterior predictive simulation to exploit summary statistics of both the data and model parameters to test the goodness-of-fit of standard models of evolution. We apply the method to test the selective neutrality of molecular evolution in non-recombining gene genealogies and we demonstrate the utility of our method on four real data sets, identifying significant departures of neutrality in human influenza A virus, even after controlling for variation in population size. Importantly, by employing a full model-based Bayesian analysis, our method separates the effects of demography from the effects of selection. The method also allows multiple summary statistics to be used in concert, thus potentially increasing sensitivity. Furthermore, our method remains useful in situations where analytical expectations and variances of summary statistics are not available. This aspect has great potential for the analysis of temporally spaced data, an expanding area previously ignored for limited availability of theory and methods.

Characterization of Inclusion Populations in Mn-Si Deoxidized Steel

NASA Astrophysics Data System (ADS)

García-Carbajal, Alfonso; Herrera-Trejo, Martín; Castro-Cedeño, Edgar-Ivan; Castro-Román, Manuel; Martinez-Enriquez, Arturo-Isaias

2017-12-01

Four plant heats of Mn-Si deoxidized steel were conducted to follow the evolution of the inclusion population through ladle furnace (LF) treatment and subsequent vacuum treatment (VT). The liquid steel was sampled, and the chemical composition and size distribution of the inclusion populations were characterized. The Gumbel generalized extreme-value (GEV) and generalized Pareto (GP) distributions were used for the statistical analysis of the inclusion size distributions. The inclusions found at the beginning of the LF treatment were mostly fully liquid SiO2-Al2O3-MnO inclusions, which then evolved into fully liquid SiO2-Al2O3-CaO-MgO and partly liquid SiO2-CaO-MgO-(Al2O3-MgO) inclusions detected at the end of the VT. The final fully liquid inclusions had a desirable chemical composition for plastic behavior in subsequent metallurgical operations. The GP distribution was found to be undesirable for statistical analysis. The GEV distribution approach led to shape parameter values different from the zero value hypothesized from the Gumbel distribution. According to the GEV approach, some of the final inclusion size distributions had statistically significant differences, whereas the Gumbel approach predicted no statistically significant differences. The heats were organized according to indicators of inclusion cleanliness and a statistical comparison of the size distributions.

The Population Tracking Model: A Simple, Scalable Statistical Model for Neural Population Data

PubMed Central

O'Donnell, Cian; alves, J. Tiago Gonç; Whiteley, Nick; Portera-Cailliau, Carlos; Sejnowski, Terrence J.

2017-01-01

Our understanding of neural population coding has been limited by a lack of analysis methods to characterize spiking data from large populations. The biggest challenge comes from the fact that the number of possible network activity patterns scales exponentially with the number of neurons recorded (∼2Neurons). Here we introduce a new statistical method for characterizing neural population activity that requires semi-independent fitting of only as many parameters as the square of the number of neurons, requiring drastically smaller data sets and minimal computation time. The model works by matching the population rate (the number of neurons synchronously active) and the probability that each individual neuron fires given the population rate. We found that this model can accurately fit synthetic data from up to 1000 neurons. We also found that the model could rapidly decode visual stimuli from neural population data from macaque primary visual cortex about 65 ms after stimulus onset. Finally, we used the model to estimate the entropy of neural population activity in developing mouse somatosensory cortex and, surprisingly, found that it first increases, and then decreases during development. This statistical model opens new options for interrogating neural population data and can bolster the use of modern large-scale in vivo Ca2+ and voltage imaging tools. PMID:27870612

Trends in incidence of lung cancer in Croatia from 2001 to 2013: gender and regional differences

PubMed Central

Siroglavić, Katarina-Josipa; Polić Vižintin, Marina; Tripković, Ingrid; Šekerija, Mario; Kukulj, Suzana

2017-01-01

Aim To provide an overview of the lung cancer incidence trends in the City of Zagreb (Zagreb), Split-Dalmatia County (SDC), and Croatia in the period from 2001 to 2013. Method Incidence data were obtained from the Croatian National Cancer Registry. For calculating incidence rates per 100 000 population, we used population estimates for the period 2001-2013 from the Croatian Bureau of Statistics. Age-standardized rates of lung cancer incidence were calculated by the direct standardization method using the European Standard Population. To describe incidence trends, we used joinpoint regression analysis. Results Joinpoint analysis showed a statistically significant decrease in lung cancer incidence in men in all regions, with an annual percentage change (APC) of -2.2% for Croatia, 1.9% for Zagreb, and -2.0% for SDC. In women, joinpoint analysis showed a statistically significant increase in the incidence for Croatia, with APC of 1.4%, a statistically significant increase of 1.0% for Zagreb, and no significant change in trend for SDC. In both genders, joinpoint analysis showed a significant decrease in age-standardized incidence rates of lung cancer, with APC of -1.3% for Croatia, -1.1% for Zagreb, and -1.6% for SDC. Conclusion There was an increase in female lung cancer incidence rate and a decrease in male lung cancer incidence rate in Croatia in 2001-20013 period, with similar patterns observed in all the investigated regions. These results highlight the importance of smoking prevention and cessation policies, especially among women and young people. PMID:29094814

The effect of rare variants on inflation of the test statistics in case-control analyses.

PubMed

Pirie, Ailith; Wood, Angela; Lush, Michael; Tyrer, Jonathan; Pharoah, Paul D P

2015-02-20

The detection of bias due to cryptic population structure is an important step in the evaluation of findings of genetic association studies. The standard method of measuring this bias in a genetic association study is to compare the observed median association test statistic to the expected median test statistic. This ratio is inflated in the presence of cryptic population structure. However, inflation may also be caused by the properties of the association test itself particularly in the analysis of rare variants. We compared the properties of the three most commonly used association tests: the likelihood ratio test, the Wald test and the score test when testing rare variants for association using simulated data. We found evidence of inflation in the median test statistics of the likelihood ratio and score tests for tests of variants with less than 20 heterozygotes across the sample, regardless of the total sample size. The test statistics for the Wald test were under-inflated at the median for variants below the same minor allele frequency. In a genetic association study, if a substantial proportion of the genetic variants tested have rare minor allele frequencies, the properties of the association test may mask the presence or absence of bias due to population structure. The use of either the likelihood ratio test or the score test is likely to lead to inflation in the median test statistic in the absence of population structure. In contrast, the use of the Wald test is likely to result in under-inflation of the median test statistic which may mask the presence of population structure.

In defence of model-based inference in phylogeography

PubMed Central

Beaumont, Mark A.; Nielsen, Rasmus; Robert, Christian; Hey, Jody; Gaggiotti, Oscar; Knowles, Lacey; Estoup, Arnaud; Panchal, Mahesh; Corander, Jukka; Hickerson, Mike; Sisson, Scott A.; Fagundes, Nelson; Chikhi, Lounès; Beerli, Peter; Vitalis, Renaud; Cornuet, Jean-Marie; Huelsenbeck, John; Foll, Matthieu; Yang, Ziheng; Rousset, Francois; Balding, David; Excoffier, Laurent

2017-01-01

Recent papers have promoted the view that model-based methods in general, and those based on Approximate Bayesian Computation (ABC) in particular, are flawed in a number of ways, and are therefore inappropriate for the analysis of phylogeographic data. These papers further argue that Nested Clade Phylogeographic Analysis (NCPA) offers the best approach in statistical phylogeography. In order to remove the confusion and misconceptions introduced by these papers, we justify and explain the reasoning behind model-based inference. We argue that ABC is a statistically valid approach, alongside other computational statistical techniques that have been successfully used to infer parameters and compare models in population genetics. We also examine the NCPA method and highlight numerous deficiencies, either when used with single or multiple loci. We further show that the ages of clades are carelessly used to infer ages of demographic events, that these ages are estimated under a simple model of panmixia and population stationarity but are then used under different and unspecified models to test hypotheses, a usage the invalidates these testing procedures. We conclude by encouraging researchers to study and use model-based inference in population genetics. PMID:29284924

Preparing for the first meeting with a statistician.

PubMed

De Muth, James E

2008-12-15

Practical statistical issues that should be considered when performing data collection and analysis are reviewed. The meeting with a statistician should take place early in the research development before any study data are collected. The process of statistical analysis involves establishing the research question, formulating a hypothesis, selecting an appropriate test, sampling correctly, collecting data, performing tests, and making decisions. Once the objectives are established, the researcher can determine the characteristics or demographics of the individuals required for the study, how to recruit volunteers, what type of data are needed to answer the research question(s), and the best methods for collecting the required information. There are two general types of statistics: descriptive and inferential. Presenting data in a more palatable format for the reader is called descriptive statistics. Inferential statistics involve making an inference or decision about a population based on results obtained from a sample of that population. In order for the results of a statistical test to be valid, the sample should be representative of the population from which it is drawn. When collecting information about volunteers, researchers should only collect information that is directly related to the study objectives. Important information that a statistician will require first is an understanding of the type of variables involved in the study and which variables can be controlled by researchers and which are beyond their control. Data can be presented in one of four different measurement scales: nominal, ordinal, interval, or ratio. Hypothesis testing involves two mutually exclusive and exhaustive statements related to the research question. Statisticians should not be replaced by computer software, and they should be consulted before any research data are collected. When preparing to meet with a statistician, the pharmacist researcher should be familiar with the steps of statistical analysis and consider several questions related to the study to be conducted.

Analysis of biochemical genetic data on Jewish populations: II. Results and interpretations of heterogeneity indices and distance measures with respect to standards.

PubMed

Karlin, S; Kenett, R; Bonné-Tamir, B

1979-05-01

A nonparametric statistical methodology is used for the analysis of biochemical frequency data observed on a series of nine Jewish and six non-Jewish populations. Two categories of statistics are used: heterogeneity indices and various distance measures with respect to a standard. The latter are more discriminating in exploiting historical, geographical and culturally relevant information. A number of partial orderings and distance relationships among the populations are determined. Our concern in this study is to analyze similarities and differences among the Jewish populations, in terms of the gene frequency distributions for a number of genetic markers. Typical questions discussed are as follows: These Jewish populations differ in certain morphological and anthropometric traits. Are there corresponding differences in biochemical genetic constitution? How can we assess the extent of heterogeneity between and within groupings? Which class of markers (blood typings or protein loci) discriminates better among the separate populations? The results are quite surprising. For example, we found the Ashkenazi, Sephardi and Iraqi Jewish populations to be consistently close in genetic constitution and distant from all the other populations, namely the Yemenite and Cochin Jews, the Arabs, and the non-Jewish German and Russian populations. We found the Polish Jewish community the most heterogeneous among all Jewish populations. The blood loci discriminate better than the protein loci. A number of possible interpretations and hypotheses for these and other results are offered. The method devised for this analysis should prove useful in studying similarities and differences for other groups of populations for which substantial biochemical polymorphic data are available.

Lognormal Distribution of Cellular Uptake of Radioactivity: Statistical Analysis of α-Particle Track Autoradiography

PubMed Central

Neti, Prasad V.S.V.; Howell, Roger W.

2010-01-01

Recently, the distribution of radioactivity among a population of cells labeled with 210Po was shown to be well described by a log-normal (LN) distribution function (J Nucl Med. 2006;47:1049–1058) with the aid of autoradiography. To ascertain the influence of Poisson statistics on the interpretation of the autoradiographic data, the present work reports on a detailed statistical analysis of these earlier data. Methods The measured distributions of α-particle tracks per cell were subjected to statistical tests with Poisson, LN, and Poisson-lognormal (P-LN) models. Results The LN distribution function best describes the distribution of radioactivity among cell populations exposed to 0.52 and 3.8 kBq/mL of 210Po-citrate. When cells were exposed to 67 kBq/mL, the P-LN distribution function gave a better fit; however, the underlying activity distribution remained log-normal. Conclusion The present analysis generally provides further support for the use of LN distributions to describe the cellular uptake of radioactivity. Care should be exercised when analyzing autoradiographic data on activity distributions to ensure that Poisson processes do not distort the underlying LN distribution. PMID:18483086

Population analysis of the cingulum bundle using the tubular surface model for schizophrenia detection

NASA Astrophysics Data System (ADS)

Mohan, Vandana; Sundaramoorthi, Ganesh; Kubicki, Marek; Terry, Douglas; Tannenbaum, Allen

2010-03-01

We propose a novel framework for population analysis of DW-MRI data using the Tubular Surface Model. We focus on the Cingulum Bundle (CB) - a major tract for the Limbic System and the main connection of the Cingulate Gyrus, which has been associated with several aspects of Schizophrenia symptomatology. The Tubular Surface Model represents a tubular surface as a center-line with an associated radius function. It provides a natural way to sample statistics along the length of the fiber bundle and reduces the registration of fiber bundle surfaces to that of 4D curves. We apply our framework to a population of 20 subjects (10 normal, 10 schizophrenic) and obtain excellent results with neural network based classification (90% sensitivity, 95% specificity) as well as unsupervised clustering (k-means). Further, we apply statistical analysis to the feature data and characterize the discrimination ability of local regions of the CB, as a step towards localizing CB regions most relevant to Schizophrenia.

A Comparison of Four Estimators of a Population Measure of Model Fit in Covariance Structure Analysis

ERIC Educational Resources Information Center

Zhang, Wei

2008-01-01

A major issue in the utilization of covariance structure analysis is model fit evaluation. Recent years have witnessed increasing interest in various test statistics and so-called fit indexes, most of which are actually based on or closely related to F[subscript 0], a measure of model fit in the population. This study aims to provide a systematic…

Connectivity-based fixel enhancement: Whole-brain statistical analysis of diffusion MRI measures in the presence of crossing fibres

PubMed Central

Raffelt, David A.; Smith, Robert E.; Ridgway, Gerard R.; Tournier, J-Donald; Vaughan, David N.; Rose, Stephen; Henderson, Robert; Connelly, Alan

2015-01-01

In brain regions containing crossing fibre bundles, voxel-average diffusion MRI measures such as fractional anisotropy (FA) are difficult to interpret, and lack within-voxel single fibre population specificity. Recent work has focused on the development of more interpretable quantitative measures that can be associated with a specific fibre population within a voxel containing crossing fibres (herein we use fixel to refer to a specific fibre population within a single voxel). Unfortunately, traditional 3D methods for smoothing and cluster-based statistical inference cannot be used for voxel-based analysis of these measures, since the local neighbourhood for smoothing and cluster formation can be ambiguous when adjacent voxels may have different numbers of fixels, or ill-defined when they belong to different tracts. Here we introduce a novel statistical method to perform whole-brain fixel-based analysis called connectivity-based fixel enhancement (CFE). CFE uses probabilistic tractography to identify structurally connected fixels that are likely to share underlying anatomy and pathology. Probabilistic connectivity information is then used for tract-specific smoothing (prior to the statistical analysis) and enhancement of the statistical map (using a threshold-free cluster enhancement-like approach). To investigate the characteristics of the CFE method, we assessed sensitivity and specificity using a large number of combinations of CFE enhancement parameters and smoothing extents, using simulated pathology generated with a range of test-statistic signal-to-noise ratios in five different white matter regions (chosen to cover a broad range of fibre bundle features). The results suggest that CFE input parameters are relatively insensitive to the characteristics of the simulated pathology. We therefore recommend a single set of CFE parameters that should give near optimal results in future studies where the group effect is unknown. We then demonstrate the proposed method by comparing apparent fibre density between motor neurone disease (MND) patients with control subjects. The MND results illustrate the benefit of fixel-specific statistical inference in white matter regions that contain crossing fibres. PMID:26004503

Monte Carlo Simulation for Perusal and Practice.

ERIC Educational Resources Information Center

Brooks, Gordon P.; Barcikowski, Robert S.; Robey, Randall R.

The meaningful investigation of many problems in statistics can be solved through Monte Carlo methods. Monte Carlo studies can help solve problems that are mathematically intractable through the analysis of random samples from populations whose characteristics are known to the researcher. Using Monte Carlo simulation, the values of a statistic are…

Qualitative Meta-Analysis on the Hospital Task: Implications for Research

ERIC Educational Resources Information Center

Noll, Jennifer; Sharma, Sashi

2014-01-01

The "law of large numbers" indicates that as sample size increases, sample statistics become less variable and more closely estimate their corresponding population parameters. Different research studies investigating how people consider sample size when evaluating the reliability of a sample statistic have found a wide range of…

A Geospatial Statistical Analysis of the Density of Lottery Outlets within Ethnically Concentrated Neighborhoods

ERIC Educational Resources Information Center

Wiggins, Lyna; Nower, Lia; Mayers, Raymond Sanchez; Peterson, N. Andrew

2010-01-01

This study examines the density of lottery outlets within ethnically concentrated neighborhoods in Middlesex County, New Jersey, using geospatial statistical analyses. No prior studies have empirically examined the relationship between lottery outlet density and population demographics. Results indicate that lottery outlets were not randomly…

A Third Moment Adjusted Test Statistic for Small Sample Factor Analysis

PubMed Central

Lin, Johnny; Bentler, Peter M.

2012-01-01

Goodness of fit testing in factor analysis is based on the assumption that the test statistic is asymptotically chi-square; but this property may not hold in small samples even when the factors and errors are normally distributed in the population. Robust methods such as Browne’s asymptotically distribution-free method and Satorra Bentler’s mean scaling statistic were developed under the presumption of non-normality in the factors and errors. This paper finds new application to the case where factors and errors are normally distributed in the population but the skewness of the obtained test statistic is still high due to sampling error in the observed indicators. An extension of Satorra Bentler’s statistic is proposed that not only scales the mean but also adjusts the degrees of freedom based on the skewness of the obtained test statistic in order to improve its robustness under small samples. A simple simulation study shows that this third moment adjusted statistic asymptotically performs on par with previously proposed methods, and at a very small sample size offers superior Type I error rates under a properly specified model. Data from Mardia, Kent and Bibby’s study of students tested for their ability in five content areas that were either open or closed book were used to illustrate the real-world performance of this statistic. PMID:23144511

Comparison of Salmonella enteritidis phage types isolated from layers and humans in Belgium in 2005.

PubMed

Welby, Sarah; Imberechts, Hein; Riocreux, Flavien; Bertrand, Sophie; Dierick, Katelijne; Wildemauwe, Christa; Hooyberghs, Jozef; Van der Stede, Yves

2011-08-01

The aim of this study was to investigate the available results for Belgium of the European Union coordinated monitoring program (2004/665 EC) on Salmonella in layers in 2005, as well as the results of the monthly outbreak reports of Salmonella Enteritidis in humans in 2005 to identify a possible statistical significant trend in both populations. Separate descriptive statistics and univariate analysis were carried out and the parametric and/or non-parametric hypothesis tests were conducted. A time cluster analysis was performed for all Salmonella Enteritidis phage types (PTs) isolated. The proportions of each Salmonella Enteritidis PT in layers and in humans were compared and the monthly distribution of the most common PT, isolated in both populations, was evaluated. The time cluster analysis revealed significant clusters during the months May and June for layers and May, July, August, and September for humans. PT21, the most frequently isolated PT in both populations in 2005, seemed to be responsible of these significant clusters. PT4 was the second most frequently isolated PT. No significant difference was found for the monthly trend evolution of both PT in both populations based on parametric and non-parametric methods. A similar monthly trend of PT distribution in humans and layers during the year 2005 was observed. The time cluster analysis and the statistical significance testing confirmed these results. Moreover, the time cluster analysis showed significant clusters during the summer time and slightly delayed in time (humans after layers). These results suggest a common link between the prevalence of Salmonella Enteritidis in layers and the occurrence of the pathogen in humans. Phage typing was confirmed to be a useful tool for identifying temporal trends.

Estimating population diversity with CatchAll

USDA-ARS?s Scientific Manuscript database

The massive quantity of data produced by next-generation sequencing has created a pressing need for advanced statistical tools, in particular for analysis of bacterial and phage communities. Here we address estimating the total diversity in a population – the species richness. This is an important s...

The relative effects of habitat loss and fragmentation on population genetic variation in the red-cockaded woodpecker (Picoides borealis).

PubMed

Bruggeman, Douglas J; Wiegand, Thorsten; Fernández, Néstor

2010-09-01

The relative influence of habitat loss, fragmentation and matrix heterogeneity on the viability of populations is a critical area of conservation research that remains unresolved. Using simulation modelling, we provide an analysis of the influence both patch size and patch isolation have on abundance, effective population size (N(e)) and F(ST). An individual-based, spatially explicit population model based on 15 years of field work on the red-cockaded woodpecker (Picoides borealis) was applied to different landscape configurations. The variation in landscape patterns was summarized using spatial statistics based on O-ring statistics. By regressing demographic and genetics attributes that emerged across the landscape treatments against proportion of total habitat and O-ring statistics, we show that O-ring statistics provide an explicit link between population processes, habitat area, and critical thresholds of fragmentation that affect those processes. Spatial distances among land cover classes that affect biological processes translated into critical scales at which the measures of landscape structure correlated best with genetic indices. Therefore our study infers pattern from process, which contrasts with past studies of landscape genetics. We found that population genetic structure was more strongly affected by fragmentation than population size, which suggests that examining only population size may limit recognition of fragmentation effects that erode genetic variation. If effective population size is used to set recovery goals for endangered species, then habitat fragmentation effects may be sufficiently strong to prevent evaluation of recovery based on the ratio of census:effective population size alone.

Cross-Population Joint Analysis of eQTLs: Fine Mapping and Functional Annotation

PubMed Central

Wen, Xiaoquan; Luca, Francesca; Pique-Regi, Roger

2015-01-01

Mapping expression quantitative trait loci (eQTLs) has been shown as a powerful tool to uncover the genetic underpinnings of many complex traits at molecular level. In this paper, we present an integrative analysis approach that leverages eQTL data collected from multiple population groups. In particular, our approach effectively identifies multiple independent cis-eQTL signals that are consistent across populations, accounting for population heterogeneity in allele frequencies and linkage disequilibrium patterns. Furthermore, by integrating genomic annotations, our analysis framework enables high-resolution functional analysis of eQTLs. We applied our statistical approach to analyze the GEUVADIS data consisting of samples from five population groups. From this analysis, we concluded that i) jointly analysis across population groups greatly improves the power of eQTL discovery and the resolution of fine mapping of causal eQTL ii) many genes harbor multiple independent eQTLs in their cis regions iii) genetic variants that disrupt transcription factor binding are significantly enriched in eQTLs (p-value = 4.93 × 10-22). PMID:25906321

Bangladesh.

PubMed

Ahmed, K S

1979-01-01

In Bangladesh the Population Control and Family Planning Division of the Ministry of Health and Population Control has decided to delegate increased financial and administrative powers to the officers of the family planning program at the district level and below. Currently, about 20,000 family planning workers and officials are at work in rural areas. The government believes that the success of the entire family planning program depends on the performance of workers in rural areas, because that is where about 90% of the population lives. Awareness of the need to improve statistical data in Bangladesh has been increasing, particularly in regard to the development of rural areas. An accurate statistical profile of rural Bangladesh is crucial to the formation, implementation and evaluation of rural development programs. A Seminar on Statistics for Rural Development will be held from June 18-20, 1980. The primary objectives of the Seminar are to make an exhaustive analysis of the current availability of statistics required for rural development programs and to consider methodological and operational improvements toward building up an adequate data base.

Universal self-similarity of propagating populations

NASA Astrophysics Data System (ADS)

Eliazar, Iddo; Klafter, Joseph

2010-07-01

This paper explores the universal self-similarity of propagating populations. The following general propagation model is considered: particles are randomly emitted from the origin of a d -dimensional Euclidean space and propagate randomly and independently of each other in space; all particles share a statistically common—yet arbitrary—motion pattern; each particle has its own random propagation parameters—emission epoch, motion frequency, and motion amplitude. The universally self-similar statistics of the particles’ displacements and first passage times (FPTs) are analyzed: statistics which are invariant with respect to the details of the displacement and FPT measurements and with respect to the particles’ underlying motion pattern. Analysis concludes that the universally self-similar statistics are governed by Poisson processes with power-law intensities and by the Fréchet and Weibull extreme-value laws.

Universal self-similarity of propagating populations.

PubMed

Eliazar, Iddo; Klafter, Joseph

2010-07-01

This paper explores the universal self-similarity of propagating populations. The following general propagation model is considered: particles are randomly emitted from the origin of a d-dimensional Euclidean space and propagate randomly and independently of each other in space; all particles share a statistically common--yet arbitrary--motion pattern; each particle has its own random propagation parameters--emission epoch, motion frequency, and motion amplitude. The universally self-similar statistics of the particles' displacements and first passage times (FPTs) are analyzed: statistics which are invariant with respect to the details of the displacement and FPT measurements and with respect to the particles' underlying motion pattern. Analysis concludes that the universally self-similar statistics are governed by Poisson processes with power-law intensities and by the Fréchet and Weibull extreme-value laws.

Forensic-paternity effectiveness and genetics population analysis of six non-CODIS mini-STR loci (D1S1656, D2S441, D6S1043, D10S1248, D12S391, D22S1045) and SE33 in Mestizo and Amerindian populations from Mexico.

PubMed

Burguete-Argueta, Nelsi; Martínez De la Cruz, Braulio; Camacho-Mejorado, Rafael; Santana, Carla; Noris, Gino; López-Bayghen, Esther; Arellano-Galindo, José; Majluf-Cruz, Abraham; Antonio Meraz-Ríos, Marco; Gómez, Rocío

2016-11-01

STRs are powerful tools intensively used in forensic and kinship studies. In order to assess the effectiveness of non-CODIS genetic markers in forensic and paternity tests, the genetic composition of six mini short tandem repeats-mini-STRs-(D1S1656, D2S441, D6S1043, D10S1248, D12S391, D22S1045) and the microsatellite SE33 in Mestizo and Amerindian populations from Mexico were studied. Using multiplex polymerase chain reactions and capillary electrophoresis, this study genotyped all loci from 870 chromosomes and evaluated the statistical genetic parameters. All mini-STRs studied were in agreement with HW and linkage equilibrium; however, an important HW departure for SE33 was found in the Mestizo population (p ≤ 0.0001). Regarding paternity and forensic statistical parameters, high values of combined power discrimination and mean power of exclusion were found using these seven markers. The principal co-ordinate analysis based on allele frequencies of three mini-STRs showed the complex genetic architecture of the Mestizo population. The results indicate that this set of loci is suitable to genetically identify individuals in the Mexican population, supporting its effectiveness in human identification casework. In addition, these findings add new statistical values and emphasise the importance of the use of non-CODIS markers in complex populations in order to avoid erroneous assumptions.

An analysis of population and social change in London wards in the 1980s.

PubMed

Congdon, P

1989-01-01

"This paper discusses the estimation and projection of small area populations in London, [England] and considers trends in intercensal social and demographic indices which can be calculated using these estimates. Information available annually on vital statistics and electorates is combined with detailed data from the Census Small Area Statistics to derive demographic component based population estimates for London's electoral wards over five year periods. The availability of age disaggregated population estimates permits derivation of small area social indicators for intercensal years, for example, of unemployment and mortality. Trends in spatial inequality of such indicators during the 1980s are analysed and point to continuing wide differentials. A typology of population and social indicators gives an indication of the small area distribution of the recent population turnaround in inner London, and of its association with other social processes such as gentrification and ethnic concentration." excerpt

Heterogeneous Structure of Stem Cells Dynamics: Statistical Models and Quantitative Predictions

PubMed Central

Bogdan, Paul; Deasy, Bridget M.; Gharaibeh, Burhan; Roehrs, Timo; Marculescu, Radu

2014-01-01

Understanding stem cell (SC) population dynamics is essential for developing models that can be used in basic science and medicine, to aid in predicting cells fate. These models can be used as tools e.g. in studying patho-physiological events at the cellular and tissue level, predicting (mal)functions along the developmental course, and personalized regenerative medicine. Using time-lapsed imaging and statistical tools, we show that the dynamics of SC populations involve a heterogeneous structure consisting of multiple sub-population behaviors. Using non-Gaussian statistical approaches, we identify the co-existence of fast and slow dividing subpopulations, and quiescent cells, in stem cells from three species. The mathematical analysis also shows that, instead of developing independently, SCs exhibit a time-dependent fractal behavior as they interact with each other through molecular and tactile signals. These findings suggest that more sophisticated models of SC dynamics should view SC populations as a collective and avoid the simplifying homogeneity assumption by accounting for the presence of more than one dividing sub-population, and their multi-fractal characteristics. PMID:24769917

Analysis of promoter polymorphism in monoamine oxidase A (MAOA) gene in completed suicide on Slovenian population.

PubMed

Uršič, Katarina; Zupanc, Tomaž; Paska, Alja Videtič

2018-04-23

Suicide is a well-defined public health problem and is a complex phenomenon influenced by a number of different risk factors, including genetic ones. Numerous studies have examined serotonin system genes. Monoamine oxidase A (MAO-A) is an outer mitochondrial membrane enzyme which is involved in the metabolic pathway of serotonin degradation. Upstream variable number of tandem repeats (uVNTR) in the promoter region of MAOA gene affects the activity of transcription. In the present study we genotyped MAOA-uVNTR polymorphism in 266 suicide victims and 191 control subjects of Slovenian population, which ranks among the European and world populations with the highest suicide rate. Genotyping was performed with polymerase chain reaction and agarose gel electrophoresis. Using a separate statistical analysis for female and male subjects we determined the differences in genotype distributions of MAOA-uVNTR polymorphism between the studied groups. Statistical analysis showed a trend towards 3R allele and suicide, and associated 3R allele with non-violent suicide method on stratified data (20 suicide victims). This is the first study associating highly suicidal Slovenian population with MAOA-uVNTR polymorphism. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis of biochemical genetic data on Jewish populations: II. Results and interpretations of heterogeneity indices and distance measures with respect to standards.

PubMed Central

Karlin, S; Kenett, R; Bonné-Tamir, B

1979-01-01

A nonparametric statistical methodology is used for the analysis of biochemical frequency data observed on a series of nine Jewish and six non-Jewish populations. Two categories of statistics are used: heterogeneity indices and various distance measures with respect to a standard. The latter are more discriminating in exploiting historical, geographical and culturally relevant information. A number of partial orderings and distance relationships among the populations are determined. Our concern in this study is to analyze similarities and differences among the Jewish populations, in terms of the gene frequency distributions for a number of genetic markers. Typical questions discussed are as follows: These Jewish populations differ in certain morphological and anthropometric traits. Are there corresponding differences in biochemical genetic constitution? How can we assess the extent of heterogeneity between and within groupings? Which class of markers (blood typings or protein loci) discriminates better among the separate populations? The results are quite surprising. For example, we found the Ashkenazi, Sephardi and Iraqi Jewish populations to be consistently close in genetic constitution and distant from all the other populations, namely the Yemenite and Cochin Jews, the Arabs, and the non-Jewish German and Russian populations. We found the Polish Jewish community the most heterogeneous among all Jewish populations. The blood loci discriminate better than the protein loci. A number of possible interpretations and hypotheses for these and other results are offered. The method devised for this analysis should prove useful in studying similarities and differences for other groups of populations for which substantial biochemical polymorphic data are available. PMID:380330

Descriptive statistics and correlation analysis of agronomic traits in a maize recombinant inbred line population.

PubMed

Zhang, H M; Hui, G Q; Luo, Q; Sun, Y; Liu, X H

2014-01-21

Maize (Zea mays L.) is one of the most important crops in the world. In this study, 13 agronomic traits of a recombinant inbred line population that was derived from the cross between Mo17 and Huangzao4 were investigated in maize: ear diameter, ear length, ear axis diameter, ear weight, plant height, ear height, days to pollen shed (DPS), days to silking (DS), the interval between DPS and DS, 100-kernel weight, kernel test weight, ear kernel weight, and kernel rate. Furthermore, the descriptive statistics and correlation analysis of the 13 traits were performed using the SPSS 11.5 software. The results providing the phenotypic data here are needed for the quantitative trait locus mapping of these agronomic traits.

The Relation Between Inflation in Type-I and Type-II Error Rate and Population Divergence in Genome-Wide Association Analysis of Multi-Ethnic Populations.

PubMed

Derks, E M; Zwinderman, A H; Gamazon, E R

2017-05-01

Population divergence impacts the degree of population stratification in Genome Wide Association Studies. We aim to: (i) investigate type-I error rate as a function of population divergence (F ST ) in multi-ethnic (admixed) populations; (ii) evaluate the statistical power and effect size estimates; and (iii) investigate the impact of population stratification on the results of gene-based analyses. Quantitative phenotypes were simulated. Type-I error rate was investigated for Single Nucleotide Polymorphisms (SNPs) with varying levels of F ST between the ancestral European and African populations. Type-II error rate was investigated for a SNP characterized by a high value of F ST . In all tests, genomic MDS components were included to correct for population stratification. Type-I and type-II error rate was adequately controlled in a population that included two distinct ethnic populations but not in admixed samples. Statistical power was reduced in the admixed samples. Gene-based tests showed no residual inflation in type-I error rate.

Analysis of molecular variance inferred from metric distances among DNA haplotypes: application to human mitochondrial DNA restriction data.

PubMed

Excoffier, L; Smouse, P E; Quattro, J M

1992-06-01

We present here a framework for the study of molecular variation within a single species. Information on DNA haplotype divergence is incorporated into an analysis of variance format, derived from a matrix of squared-distances among all pairs of haplotypes. This analysis of molecular variance (AMOVA) produces estimates of variance components and F-statistic analogs, designated here as phi-statistics, reflecting the correlation of haplotypic diversity at different levels of hierarchical subdivision. The method is flexible enough to accommodate several alternative input matrices, corresponding to different types of molecular data, as well as different types of evolutionary assumptions, without modifying the basic structure of the analysis. The significance of the variance components and phi-statistics is tested using a permutational approach, eliminating the normality assumption that is conventional for analysis of variance but inappropriate for molecular data. Application of AMOVA to human mitochondrial DNA haplotype data shows that population subdivisions are better resolved when some measure of molecular differences among haplotypes is introduced into the analysis. At the intraspecific level, however, the additional information provided by knowing the exact phylogenetic relations among haplotypes or by a nonlinear translation of restriction-site change into nucleotide diversity does not significantly modify the inferred population genetic structure. Monte Carlo studies show that site sampling does not fundamentally affect the significance of the molecular variance components. The AMOVA treatment is easily extended in several different directions and it constitutes a coherent and flexible framework for the statistical analysis of molecular data.

Statistics 101 for Radiologists.

PubMed

Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

2015-10-01

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. © RSNA, 2015.

OASIS 2: online application for survival analysis 2 with features for the analysis of maximal lifespan and healthspan in aging research.

PubMed

Han, Seong Kyu; Lee, Dongyeop; Lee, Heetak; Kim, Donghyo; Son, Heehwa G; Yang, Jae-Seong; Lee, Seung-Jae V; Kim, Sanguk

2016-08-30

Online application for survival analysis (OASIS) has served as a popular and convenient platform for the statistical analysis of various survival data, particularly in the field of aging research. With the recent advances in the fields of aging research that deal with complex survival data, we noticed a need for updates to the current version of OASIS. Here, we report OASIS 2 (http://sbi.postech.ac.kr/oasis2), which provides extended statistical tools for survival data and an enhanced user interface. In particular, OASIS 2 enables the statistical comparison of maximal lifespans, which is potentially useful for determining key factors that limit the lifespan of a population. Furthermore, OASIS 2 provides statistical and graphical tools that compare values in different conditions and times. That feature is useful for comparing age-associated changes in physiological activities, which can be used as indicators of "healthspan." We believe that OASIS 2 will serve as a standard platform for survival analysis with advanced and user-friendly statistical tools for experimental biologists in the field of aging research.

Effect of interleukin-6 polymorphism on risk of preterm birth within population strata: a meta-analysis.

PubMed

Wu, Wilfred; Clark, Erin A S; Stoddard, Gregory J; Watkins, W Scott; Esplin, M Sean; Manuck, Tracy A; Xing, Jinchuan; Varner, Michael W; Jorde, Lynn B

2013-04-25

Because of the role of inflammation in preterm birth (PTB), polymorphisms in and near the interleukin-6 gene (IL6) have been association study targets. Several previous studies have assessed the association between PTB and a single nucleotide polymorphism (SNP), rs1800795, located in the IL6 gene promoter region. Their results have been inconsistent and SNP frequencies have varied strikingly among different populations. We therefore conducted a meta-analysis with subgroup analysis by population strata to: (1) reduce the confounding effect of population structure, (2) increase sample size and statistical power, and (3) elucidate the association between rs1800975 and PTB. We reviewed all published papers for PTB phenotype and SNP rs1800795 genotype. Maternal genotype and fetal genotype were analyzed separately and the analyses were stratified by population. The PTB phenotype was defined as gestational age (GA) < 37 weeks, but results from earlier GA were selected when available. All studies were compared by genotype (CC versus CG+GG), based on functional studies.For the maternal genotype analysis, 1,165 PTBs and 3,830 term controls were evaluated. Populations were stratified into women of European descent (for whom the most data were available) and women of heterogeneous origin or admixed populations. All ancestry was self-reported. Women of European descent had a summary odds ratio (OR) of 0.68, (95% confidence interval (CI) 0.51 - 0.91), indicating that the CC genotype is protective against PTB. The result for non-European women was not statistically significant (OR 1.01, 95% CI 0.59 - 1.75). For the fetal genotype analysis, four studies were included; there was no significant association with PTB (OR 0.98, 95% CI 0.72 - 1.33). Sensitivity analysis showed that preterm premature rupture of membrane (PPROM) may be a confounding factor contributing to phenotype heterogeneity. IL6 SNP rs1800795 genotype CC is protective against PTB in women of European descent. It is not significant in other heterogeneous or admixed populations, or in fetal genotype analysis.Population structure is an important confounding factor that should be controlled for in studies of PTB.

DnaSAM: Software to perform neutrality testing for large datasets with complex null models.

PubMed

Eckert, Andrew J; Liechty, John D; Tearse, Brandon R; Pande, Barnaly; Neale, David B

2010-05-01

Patterns of DNA sequence polymorphisms can be used to understand the processes of demography and adaptation within natural populations. High-throughput generation of DNA sequence data has historically been the bottleneck with respect to data processing and experimental inference. Advances in marker technologies have largely solved this problem. Currently, the limiting step is computational, with most molecular population genetic software allowing a gene-by-gene analysis through a graphical user interface. An easy-to-use analysis program that allows both high-throughput processing of multiple sequence alignments along with the flexibility to simulate data under complex demographic scenarios is currently lacking. We introduce a new program, named DnaSAM, which allows high-throughput estimation of DNA sequence diversity and neutrality statistics from experimental data along with the ability to test those statistics via Monte Carlo coalescent simulations. These simulations are conducted using the ms program, which is able to incorporate several genetic parameters (e.g. recombination) and demographic scenarios (e.g. population bottlenecks). The output is a set of diversity and neutrality statistics with associated probability values under a user-specified null model that are stored in easy to manipulate text file. © 2009 Blackwell Publishing Ltd.

Big Data, Big Opportunities, and Big Challenges.

PubMed

Frelinger, Jeffrey A

2015-11-01

High-throughput assays have begun to revolutionize modern biology and medicine. The advent of cheap next-generation sequencing (NGS) has made it possible to interrogate cells and human populations as never before. Although this has allowed us to investigate the genetics, gene expression, and impacts of the microbiome, there remain both practical and conceptual challenges. These include data handling, storage, and statistical analysis, as well as an inherent problem of the analysis of heterogeneous cell populations.

[Acetabular anteversion angle of the hip in the Mexican adult population measured with computed tomography].

PubMed

Rubalcava, J; Gómez-García, F; Ríos-Reina, J L

2012-01-01

Knowledge of the radiogrametric characteristics of a specific skeletal segment in a healthy population is of the utmost clinical importance. The main justification for this study is that there is no published description of the radiogrametric parameter of acetabular anteversion in a healthy Mexican adult population. A prospective, descriptive and cross-sectional study was conducted. Individuals of both genders older than 18 years and orthopedically healthy were included. They underwent a two-dimensional axial tomographic study of both hips to measure the acetabular anteversion angles. The statistical analysis consisted of obtaining central trend and scatter measurements. A multivariate analysis of variance (ANOVA) and statistical significance were performed. 118 individuals were studied, 60 males and 58 females, with a mean age of 47.7 +/- 16.7, and a range of 18-85 years. The anteversion of the entire group was 18.6 degrees + 4.1 degrees. Anteversion in males was 17.3 degrees +/- 3.5 degrees (10 degrees - 25 degrees) and in females 19.8 degrees +/- 4.7 degrees (10 degrees - 31 degrees). There were no statistically significant differences (p < or = 0.05) in right and left anteversion in the entire group. However, there were statistically significant differences (p > or = 0.005) both in the right and left sides when males and females were compared. Our study showed that there are great variations in the anteversion ranges of a healthy population. When our results are compared with those published by other authors the mean of most measurements exceeds 15 degrees. This should be useful to make therapeutic decisions that involve acetabular anteversion.

A glossary for big data in population and public health: discussion and commentary on terminology and research methods.

PubMed

Fuller, Daniel; Buote, Richard; Stanley, Kevin

2017-11-01

The volume and velocity of data are growing rapidly and big data analytics are being applied to these data in many fields. Population and public health researchers may be unfamiliar with the terminology and statistical methods used in big data. This creates a barrier to the application of big data analytics. The purpose of this glossary is to define terms used in big data and big data analytics and to contextualise these terms. We define the five Vs of big data and provide definitions and distinctions for data mining, machine learning and deep learning, among other terms. We provide key distinctions between big data and statistical analysis methods applied to big data. We contextualise the glossary by providing examples where big data analysis methods have been applied to population and public health research problems and provide brief guidance on how to learn big data analysis methods. © 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.

Black Females in High School: A Statistical Educational Profile

ERIC Educational Resources Information Center

Muhammad, Crystal Gafford; Dixson, Adrienne D.

2008-01-01

In life as in literature, both the mainstream public and the Black community writ large, overlook the Black female experiences, both adolescent and adult. In order to contribute to the knowledge base regarding this population, we present through our study a statistical portrait of Black females in high school. To do so, we present an analysis of…

Appropriate Statistical Analysis for Two Independent Groups of Likert-Type Data

ERIC Educational Resources Information Center

Warachan, Boonyasit

2011-01-01

The objective of this research was to determine the robustness and statistical power of three different methods for testing the hypothesis that ordinal samples of five and seven Likert categories come from equal populations. The three methods are the two sample t-test with equal variances, the Mann-Whitney test, and the Kolmogorov-Smirnov test. In…

Consistent Tolerance Bounds for Statistical Distributions

NASA Technical Reports Server (NTRS)

Mezzacappa, M. A.

1983-01-01

Assumption that sample comes from population with particular distribution is made with confidence C if data lie between certain bounds. These "confidence bounds" depend on C and assumption about distribution of sampling errors around regression line. Graphical test criteria using tolerance bounds are applied in industry where statistical analysis influences product development and use. Applied to evaluate equipment life.

Optimizing human activity patterns using global sensitivity analysis.

PubMed

Fairchild, Geoffrey; Hickmann, Kyle S; Mniszewski, Susan M; Del Valle, Sara Y; Hyman, James M

2014-12-01

Implementing realistic activity patterns for a population is crucial for modeling, for example, disease spread, supply and demand, and disaster response. Using the dynamic activity simulation engine, DASim, we generate schedules for a population that capture regular (e.g., working, eating, and sleeping) and irregular activities (e.g., shopping or going to the doctor). We use the sample entropy (SampEn) statistic to quantify a schedule's regularity for a population. We show how to tune an activity's regularity by adjusting SampEn, thereby making it possible to realistically design activities when creating a schedule. The tuning process sets up a computationally intractable high-dimensional optimization problem. To reduce the computational demand, we use Bayesian Gaussian process regression to compute global sensitivity indices and identify the parameters that have the greatest effect on the variance of SampEn. We use the harmony search (HS) global optimization algorithm to locate global optima. Our results show that HS combined with global sensitivity analysis can efficiently tune the SampEn statistic with few search iterations. We demonstrate how global sensitivity analysis can guide statistical emulation and global optimization algorithms to efficiently tune activities and generate realistic activity patterns. Though our tuning methods are applied to dynamic activity schedule generation, they are general and represent a significant step in the direction of automated tuning and optimization of high-dimensional computer simulations.

Optimizing human activity patterns using global sensitivity analysis

PubMed Central

Hickmann, Kyle S.; Mniszewski, Susan M.; Del Valle, Sara Y.; Hyman, James M.

2014-01-01

Implementing realistic activity patterns for a population is crucial for modeling, for example, disease spread, supply and demand, and disaster response. Using the dynamic activity simulation engine, DASim, we generate schedules for a population that capture regular (e.g., working, eating, and sleeping) and irregular activities (e.g., shopping or going to the doctor). We use the sample entropy (SampEn) statistic to quantify a schedule’s regularity for a population. We show how to tune an activity’s regularity by adjusting SampEn, thereby making it possible to realistically design activities when creating a schedule. The tuning process sets up a computationally intractable high-dimensional optimization problem. To reduce the computational demand, we use Bayesian Gaussian process regression to compute global sensitivity indices and identify the parameters that have the greatest effect on the variance of SampEn. We use the harmony search (HS) global optimization algorithm to locate global optima. Our results show that HS combined with global sensitivity analysis can efficiently tune the SampEn statistic with few search iterations. We demonstrate how global sensitivity analysis can guide statistical emulation and global optimization algorithms to efficiently tune activities and generate realistic activity patterns. Though our tuning methods are applied to dynamic activity schedule generation, they are general and represent a significant step in the direction of automated tuning and optimization of high-dimensional computer simulations. PMID:25580080

Optimizing human activity patterns using global sensitivity analysis

DOE PAGES

Fairchild, Geoffrey; Hickmann, Kyle S.; Mniszewski, Susan M.; ...

2013-12-10

Implementing realistic activity patterns for a population is crucial for modeling, for example, disease spread, supply and demand, and disaster response. Using the dynamic activity simulation engine, DASim, we generate schedules for a population that capture regular (e.g., working, eating, and sleeping) and irregular activities (e.g., shopping or going to the doctor). We use the sample entropy (SampEn) statistic to quantify a schedule’s regularity for a population. We show how to tune an activity’s regularity by adjusting SampEn, thereby making it possible to realistically design activities when creating a schedule. The tuning process sets up a computationally intractable high-dimensional optimizationmore » problem. To reduce the computational demand, we use Bayesian Gaussian process regression to compute global sensitivity indices and identify the parameters that have the greatest effect on the variance of SampEn. Here we use the harmony search (HS) global optimization algorithm to locate global optima. Our results show that HS combined with global sensitivity analysis can efficiently tune the SampEn statistic with few search iterations. We demonstrate how global sensitivity analysis can guide statistical emulation and global optimization algorithms to efficiently tune activities and generate realistic activity patterns. Finally, though our tuning methods are applied to dynamic activity schedule generation, they are general and represent a significant step in the direction of automated tuning and optimization of high-dimensional computer simulations.« less

Guidelines for collecting and maintaining archives for genetic monitoring

Treesearch

Jennifer A. Jackson; Linda Laikre; C. Scott Baker; Katherine C. Kendall; F. W. Allendorf; M. K. Schwartz

2011-01-01

Rapid advances in molecular genetic techniques and the statistical analysis of genetic data have revolutionized the way that populations of animals, plants and microorganisms can be monitored. Genetic monitoring is the practice of using molecular genetic markers to track changes in the abundance, diversity or distribution of populations, species or ecosystems over time...

Understanding the behavioral linkages needed for designing effective interventions to increase fruit and vegetable intake in diverse populations

USDA-ARS?s Scientific Manuscript database

The design of interventions to increase fruit and vegetable consumption in a population (e.g. all men, all elementary school students) requires an underlying model that organizes the relevant literatures and provides an audience. The mediating-moderating variable model is a statistical analysis tech...

RESIDUES AND METABOLITES OF SELECTED PERSISTENT HALOGENATED HYDROCARBONS IN BLOOD SPECIMENS FROM A GENERAL POPULATION SURVEY

EPA Science Inventory

The National Center for Health Statistics collaborated with the National Human Monitoring Program of the U.S. Environmental Protection Agency (EPA) in a four-year study to assess the exposure of the general population to selected pesticides through analysis of blood serum and uri...

Statistical Modeling of the Individual: Rationale and Application of Multivariate Stationary Time Series Analysis

ERIC Educational Resources Information Center

Hamaker, Ellen L.; Dolan, Conor V.; Molenaar, Peter C. M.

2005-01-01

Results obtained with interindividual techniques in a representative sample of a population are not necessarily generalizable to the individual members of this population. In this article the specific condition is presented that must be satisfied to generalize from the interindividual level to the intraindividual level. A way to investigate…

[Population models of mental health in the Russian population: assessment of an impact of living conditions and psychiatric care resources].

PubMed

Mitikhin, V G; Yastrebov, V S; Mitikhina, I A

ОBJECTIVE: The development and use of population models of mental health in the Russian population to analyze the relationship between indicators of mental disorders, psychiatric care resources taking into account medical/demographic and socio-economic factors in the period of 1992-2015. The sources of information were: 1) the data of the Russian medical statistics on the main indicators of mental health of the Russian population and psychiatric care resources; 2) government statistics on the demographic and socio-economic situation of the population of Russia during this period. The study used system data analysis, correlation and regression analyses. Linear and nonlinear models with a high level of significance were obtained to assess the impact of socio-economic, health and demographic (population, life expectancy, migration, mortality) factors and resources of the service (primarily, manpower) on the dynamics of the main indicators (prevalence, incidence) of mental health of the population. In recent years, a decline in the prevalence and incidence of the Russian population is a consequence of the scarcity of mental health services, in particular, personnel resources.

What is too much variation? The null hypothesis in small-area analysis.

PubMed Central

Diehr, P; Cain, K; Connell, F; Volinn, E

1990-01-01

A small-area analysis (SAA) in health services research often calculates surgery rates for several small areas, compares the largest rate to the smallest, notes that the difference is large, and attempts to explain this discrepancy as a function of service availability, physician practice styles, or other factors. SAAs are often difficult to interpret because there is little theoretical basis for determining how much variation would be expected under the null hypothesis that all of the small areas have similar underlying surgery rates and that the observed variation is due to chance. We developed a computer program to simulate the distribution of several commonly used descriptive statistics under the null hypothesis, and used it to examine the variability in rates among the counties of the state of Washington. The expected variability when the null hypothesis is true is surprisingly large, and becomes worse for procedures with low incidence, for smaller populations, when there is variability among the populations of the counties, and when readmissions are possible. The characteristics of four descriptive statistics were studied and compared. None was uniformly good, but the chi-square statistic had better performance than the others. When we reanalyzed five journal articles that presented sufficient data, the results were usually statistically significant. Since SAA research today is tending to deal with low-incidence events, smaller populations, and measures where readmissions are possible, more research is needed on the distribution of small-area statistics under the null hypothesis. New standards are proposed for the presentation of SAA results. PMID:2312306

What is too much variation? The null hypothesis in small-area analysis.

PubMed

Diehr, P; Cain, K; Connell, F; Volinn, E

1990-02-01

A small-area analysis (SAA) in health services research often calculates surgery rates for several small areas, compares the largest rate to the smallest, notes that the difference is large, and attempts to explain this discrepancy as a function of service availability, physician practice styles, or other factors. SAAs are often difficult to interpret because there is little theoretical basis for determining how much variation would be expected under the null hypothesis that all of the small areas have similar underlying surgery rates and that the observed variation is due to chance. We developed a computer program to simulate the distribution of several commonly used descriptive statistics under the null hypothesis, and used it to examine the variability in rates among the counties of the state of Washington. The expected variability when the null hypothesis is true is surprisingly large, and becomes worse for procedures with low incidence, for smaller populations, when there is variability among the populations of the counties, and when readmissions are possible. The characteristics of four descriptive statistics were studied and compared. None was uniformly good, but the chi-square statistic had better performance than the others. When we reanalyzed five journal articles that presented sufficient data, the results were usually statistically significant. Since SAA research today is tending to deal with low-incidence events, smaller populations, and measures where readmissions are possible, more research is needed on the distribution of small-area statistics under the null hypothesis. New standards are proposed for the presentation of SAA results.

Skeletal and dental effects of rapid maxillary expansion assessed through three-dimensional imaging: A multicenter study.

PubMed

Luebbert, Joshua; Ghoneima, Ahmed; Lagravère, Manuel O

2016-03-01

The aim of this study was to determine the skeletal and dental changes in rapid maxillary expansion treatments in two different populations assessed through cone-beam computer tomography (CBCT). Twenty-one patients from Edmonton, Canada and 16 patients from Cairo, Egypt with maxillary transverse deficiency (11-17 years old) were treated with a tooth-borne maxillary expander (Hyrax). CBCTs were obtained from each patient at two time points (initial T1 and at removal of appliance at 3-6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on skeletal and dental anatomical structures on the cranial base, maxilla and mandible. Descriptive statistics, intraclass correlation coefficients and one-way ANOVA analysis were used to determine if there were skeletal and dental changes and if these changes were statistically different between both populations. Descriptive statistics show that dental changes were larger than skeletal changes for both populations. Skeletal and dental changes between populations were not statistically different (P<0.05) from each other with the exception of the upper incisor proclination being larger in the Indiana group (P>0.05). Rapid maxillary expansion treatments in different populations demonstrate similar skeletal and dental changes. These changes are greater on the dental structures compared to the skeletal ones in a 4:1 ratio. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

Rock Statistics at the Mars Pathfinder Landing Site, Roughness and Roving on Mars

NASA Technical Reports Server (NTRS)

Haldemann, A. F. C.; Bridges, N. T.; Anderson, R. C.; Golombek, M. P.

1999-01-01

Several rock counts have been carried out at the Mars Pathfinder landing site producing consistent statistics of rock coverage and size-frequency distributions. These rock statistics provide a primary element of "ground truth" for anchoring remote sensing information used to pick the Pathfinder, and future, landing sites. The observed rock population statistics should also be consistent with the emplacement and alteration processes postulated to govern the landing site landscape. The rock population databases can however be used in ways that go beyond the calculation of cumulative number and cumulative area distributions versus rock diameter and height. Since the spatial parameters measured to characterize each rock are determined with stereo image pairs, the rock database serves as a subset of the full landing site digital terrain model (DTM). Insofar as a rock count can be carried out in a speedier, albeit coarser, manner than the full DTM analysis, rock counting offers several operational and scientific products in the near term. Quantitative rock mapping adds further information to the geomorphic study of the landing site, and can also be used for rover traverse planning. Statistical analysis of the surface roughness using the rock count proxy DTM is sufficiently accurate when compared to the full DTM to compare with radar remote sensing roughness measures, and with rover traverse profiles.

Lack of findings for the association between obesity risk and usual sugar-sweetened beverage consumption in adults--a primary analysis of databases of CSFII-1989-1991, CSFII-1994-1998, NHANES III, and combined NHANES 1999-2002.

PubMed

Sun, Sam Z; Empie, Mark W

2007-08-01

The relationship between obesity risk and sugar-sweetened beverage (SSB) consumption was examined together with multiple lifestyle factors. Statistical analysis was performed using population dietary survey databases of USDA CSFII 1989-1991, CSFII 1994-1996, CDC NHANES III, and combined NHANES 1999-2002. Totally, 38,409 individuals, ages 20-74 years, with accompanying data of dietary intake, lifestyle factors, and anthropometrics were included in the descriptive statistics and risk analysis. Analytical results indicate that obesity risk was significantly and positively associated with gender, age, daily TV/screen watching hours and dietary fat content, and negatively associated with smoking habit, education and physical activity; obesity risk was not significantly associated with SSB consumption pattern, dietary saturated fat content and total calorie intake. No elevated BMI values or increased obesity rates were observed in populations frequently consuming SSB compared to populations infrequently consuming SSB. Additionally, one-day food consumption data was found to overestimate SSB usual intake by up to 38.9% compared to the data of multiple survey days. multiple lifestyle factors and higher dietary fat intake were significantly associated with obesity risk. Populations who frequently consumed SSB, primarily HFCS sweetened beverages, did not have a higher obesity rate or increased obesity risk than that of populations which consumed SSB infrequently.

Visualization and Image Analysis of Yeast Cells.

PubMed

Bagley, Steve

2016-01-01

When converting real-life data via visualization to numbers and then onto statistics the whole system needs to be considered so that conversion from the analogue to the digital is accurate and repeatable. Here we describe the points to consider when approaching yeast cell analysis visualization, processing, and analysis of a population by screening techniques.

Analyzing the Validity of the Adult-Adolescent Parenting Inventory for Low-Income Populations

ERIC Educational Resources Information Center

Lawson, Michael A.; Alameda-Lawson, Tania; Byrnes, Edward

2017-01-01

Objectives: The purpose of this study was to examine the construct and predictive validity of the Adult-Adolescent Parenting Inventory (AAPI-2). Methods: The validity of the AAPI-2 was evaluated using multiple statistical methods, including exploratory factor analysis, confirmatory factor analysis, and latent class analysis. These analyses were…

[Gypsy moth Lymantria dispar L. in the South Urals: Patterns in population dynamics and modelling].

PubMed

Soukhovolsky, V G; Ponomarev, V I; Sokolov, G I; Tarasova, O V; Krasnoperova, P A

2015-01-01

The analysis is conducted on population dynamics of gypsy moth from different habitats of the South Urals. The pattern of cyclic changes in population density is examined, the assessment of temporal conjugation in time series of gypsy moth population dynamics from separate habitats of the South Urals is carried out, the relationships between population density and weather conditions are studied. Based on the results obtained, a statistical model of gypsy moth population dynamics in the South Urals is designed, and estimations are given of regulatory and modifying factors effects on the population dynamics.

Comparative analysis of perceptual evaluation, acoustic analysis and indirect laryngoscopy for vocal assessment of a population with vocal complaint.

PubMed

Nemr, Kátia; Amar, Ali; Abrahão, Marcio; Leite, Grazielle Capatto de Almeida; Köhle, Juliana; Santos, Alexandra de O; Correa, Luiz Artur Costa

2005-01-01

As a result of technology evolution and development, methods of voice evaluation have changed both in medical and speech and language pathology practice. To relate the results of perceptual evaluation, acoustic analysis and medical evaluation in the diagnosis of vocal and/or laryngeal affections of the population with vocal complaint. Clinical prospective. 29 people that attended vocal health protection campaign were evaluated. They were submitted to perceptual evaluation (AFPA), acoustic analysis (AA), indirect laryngoscopy (LI) and telelaryngoscopy (TL). Correlations between medical and speech language pathology evaluation methods were established, verifying possible statistical signification with the application of Fischer Exact Test. There were statistically significant results in the correlation between AFPA and LI, AFPA and TL, LI and TL. This research study conducted in a vocal health protection campaign presented correlations between speech language pathology evaluation and perceptual evaluation and clinical evaluation, as well as between vocal affection and/or laryngeal medical exams.

Population connectivity of the plating coral Agaricia lamarcki from southwest Puerto Rico

NASA Astrophysics Data System (ADS)

Hammerman, Nicholas M.; Rivera-Vicens, Ramon E.; Galaska, Matthew P.; Weil, Ernesto; Appledoorn, Richard S.; Alfaro, Monica; Schizas, Nikolaos V.

2018-03-01

Identifying genetic connectivity and discrete population boundaries is an important objective for management of declining Caribbean reef-building corals. A double digest restriction-associated DNA sequencing protocol was utilized to generate 321 single nucleotide polymorphisms to estimate patterns of horizontal and vertical gene flow in the brooding Caribbean plate coral, Agaricia lamarcki. Individual colonies ( n = 59) were sampled from eight locations throughout southwestern Puerto Rico from six shallow ( 10-20 m) and two mesophotic habitats ( 30-40 m). Descriptive summary statistics (fixation index, F ST), analysis of molecular variance, and analysis through landscape and ecological associations and discriminant analysis of principal components estimated high population connectivity with subtle subpopulation structure among all sampling localities.

Effective Population Size, Genetic Variation, and Their Relevance for Conservation: The Bighorn Sheep in Tiburon Island and Comparisons with Managed Artiodactyls

PubMed Central

Gasca-Pineda, Jaime; Cassaigne, Ivonne; Alonso, Rogelio A.; Eguiarte, Luis E.

2013-01-01

The amount of genetic diversity in a finite biological population mostly depends on the interactions among evolutionary forces and the effective population size (N e) as well as the time since population establishment. Because the N e estimation helps to explore population demographic history, and allows one to predict the behavior of genetic diversity through time, N e is a key parameter for the genetic management of small and isolated populations. Here, we explored an N e-based approach using a bighorn sheep population on Tiburon Island, Mexico (TI) as a model. We estimated the current (N crnt) and ancestral stable (N stbl) inbreeding effective population sizes as well as summary statistics to assess genetic diversity and the demographic scenarios that could explain such diversity. Then, we evaluated the feasibility of using TI as a source population for reintroduction programs. We also included data from other bighorn sheep and artiodactyl populations in the analysis to compare their inbreeding effective size estimates. The TI population showed high levels of genetic diversity with respect to other managed populations. However, our analysis suggested that TI has been under a genetic bottleneck, indicating that using individuals from this population as the only source for reintroduction could lead to a severe genetic diversity reduction. Analyses of the published data did not show a strict correlation between H E and N crnt estimates. Moreover, we detected that ancient anthropogenic and climatic pressures affected all studied populations. We conclude that the estimation of N crnt and N stbl are informative genetic diversity estimators and should be used in addition to summary statistics for conservation and population management planning. PMID:24147115

Statistics of Low-Mass Companions to Stars: Implications for Their Origin

NASA Technical Reports Server (NTRS)

Stepinski, T. F.; Black, D. C.

2001-01-01

One of the more significant results from observational astronomy over the past few years has been the detection, primarily via radial velocity studies, of low-mass companions (LMCs) to solar-like stars. The commonly held interpretation of these is that the majority are "extrasolar planets" whereas the rest are brown dwarfs, the distinction made on the basis of apparent discontinuity in the distribution of M sin i for LMCs as revealed by a histogram. We report here results from statistical analysis of M sin i, as well as of the orbital elements data for available LMCs, to rest the assertion that the LMCs population is heterogeneous. The outcome is mixed. Solely on the basis of the distribution of M sin i a heterogeneous model is preferable. Overall, we find that a definitive statement asserting that LMCs population is heterogeneous is, at present, unjustified. In addition we compare statistics of LMCs with a comparable sample of stellar binaries. We find a remarkable statistical similarity between these two populations. This similarity coupled with marked populational dissimilarity between LMCs and acknowledged planets motivates us to suggest a common origin hypothesis for LMCs and stellar binaries as an alternative to the prevailing interpretation. We discuss merits of such a hypothesis and indicate a possible scenario for the formation of LMCs.

Log Normal Distribution of Cellular Uptake of Radioactivity: Statistical Analysis of Alpha Particle Track Autoradiography

PubMed Central

Neti, Prasad V.S.V.; Howell, Roger W.

2008-01-01

Recently, the distribution of radioactivity among a population of cells labeled with 210Po was shown to be well described by a log normal distribution function (J Nucl Med 47, 6 (2006) 1049-1058) with the aid of an autoradiographic approach. To ascertain the influence of Poisson statistics on the interpretation of the autoradiographic data, the present work reports on a detailed statistical analyses of these data. Methods The measured distributions of alpha particle tracks per cell were subjected to statistical tests with Poisson (P), log normal (LN), and Poisson – log normal (P – LN) models. Results The LN distribution function best describes the distribution of radioactivity among cell populations exposed to 0.52 and 3.8 kBq/mL 210Po-citrate. When cells were exposed to 67 kBq/mL, the P – LN distribution function gave a better fit, however, the underlying activity distribution remained log normal. Conclusions The present analysis generally provides further support for the use of LN distributions to describe the cellular uptake of radioactivity. Care should be exercised when analyzing autoradiographic data on activity distributions to ensure that Poisson processes do not distort the underlying LN distribution. PMID:16741316

Analysis of the SNPforID 52-plex markers in four Native American populations from Venezuela.

PubMed

Ruiz, Y; Chiurillo, M A; Borjas, L; Phillips, C; Lareu, M V; Carracedo, Á

2012-09-01

The SNPforID 52-plex single nucleotide polymorphisms (SNPs) were analyzed in four native Venezuelan populations: Bari, Pemon, Panare and Warao. None of the population-locus combinations showed significant departure from Hardy-Weinberg equilibrium. Calculation of forensic and statistical parameters showed lower values of genetic diversity in comparison with African and European populations, as well as other, admixed populations of neighboring regions of Caribbean, Central and South America. Significant levels of divergence were observed between the four Native Venezuelan populations as well as with other previously studied populations. Analysis of the 52-plex SNP loci with Structure provided an optimum number of population clusters of three, corresponding to Africans, Europeans and Native Americans. Analysis of admixed populations indicated a range of membership proportions for ancestral populations consisting of Native American, African and European components. The genetic differences observed in the Native American groups suggested by the 52 SNPs typed in our study are in agreement with current knowledge of the demographic history of the Americas. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

SMAR Sessions

NASA Technical Reports Server (NTRS)

Ploutz-Snyder, Robert

2011-01-01

This slide presentation is a series of educational presentations that are on the statistical function of analysis of variance (ANOVA). Analysis of Variance (ANOVA) examines variability between groups, relative to within groups, to determine whether there's evidence that the groups are not from the same population. One other presentation reviews hypothesis testing.

Genome-Wide Analysis in Brazilians Reveals Highly Differentiated Native American Genome Regions

PubMed Central

Havt, Alexandre; Nayak, Uma; Pinkerton, Relana; Farber, Emily; Concannon, Patrick; Lima, Aldo A.; Guerrant, Richard L.

2017-01-01

Despite its population, geographic size, and emerging economic importance, disproportionately little genome-scale research exists into genetic factors that predispose Brazilians to disease, or the population genetics of risk. After identification of suitable proxy populations and careful analysis of tri-continental admixture in 1,538 North-Eastern Brazilians to estimate individual ancestry and ancestral allele frequencies, we computed 400,000 genome-wide locus-specific branch length (LSBL) Fst statistics of Brazilian Amerindian ancestry compared to European and African; and a similar set of differentiation statistics for their Amerindian component compared with the closest Asian 1000 Genomes population (surprisingly, Bengalis in Bangladesh). After ranking SNPs by these statistics, we identified the top 10 highly differentiated SNPs in five genome regions in the LSBL tests of Brazilian Amerindian ancestry compared to European and African; and the top 10 SNPs in eight regions comparing their Amerindian component to the closest Asian 1000 Genomes population. We found SNPs within or proximal to the genes CIITA (rs6498115), SMC6 (rs1834619), and KLHL29 (rs2288697) were most differentiated in the Amerindian-specific branch, while SNPs in the genes ADAMTS9 (rs7631391), DOCK2 (rs77594147), SLC28A1 (rs28649017), ARHGAP5 (rs7151991), and CIITA (rs45601437) were most highly differentiated in the Asian comparison. These genes are known to influence immune function, metabolic and anthropometry traits, and embryonic development. These analyses have identified candidate genes for selection within Amerindian ancestry, and by comparison of the two analyses, those for which the differentiation may have arisen during the migration from Asia to the Americas. PMID:28100790

Estimation of Total Length of Femur from its Proximal and Distal Segmental Measurements of Disarticulated Femur Bones of Nepalese Population using Regression Equation Method.

PubMed

Khanal, Laxman; Shah, Sandip; Koirala, Sarun

2017-03-01

Length of long bones is taken as an important contributor for estimating one of the four elements of forensic anthropology i.e., stature of the individual. Since physical characteristics of the individual differ among different groups of population, population specific studies are needed for estimating the total length of femur from its segment measurements. Since femur is not always recovered intact in forensic cases, it was the aim of this study to derive regression equations from measurements of proximal and distal fragments in Nepalese population. A cross-sectional study was done among 60 dry femora (30 from each side) without sex determination in anthropometry laboratory. Along with maximum femoral length, four proximal and four distal segmental measurements were measured following the standard method with the help of osteometric board, measuring tape and digital Vernier's caliper. Bones with gross defects were excluded from the study. Measured values were recorded separately for right and left side. Statistical Package for Social Science (SPSS version 11.5) was used for statistical analysis. The value of segmental measurements were different between right and left side but statistical difference was not significant except for depth of medial condyle (p=0.02). All the measurements were positively correlated and found to have linear relationship with the femoral length. With the help of regression equation, femoral length can be calculated from the segmental measurements; and then femoral length can be used to calculate the stature of the individual. The data collected may contribute in the analysis of forensic bone remains in study population.

Interpreting statistics of small lunar craters

NASA Technical Reports Server (NTRS)

Schultz, P. H.; Gault, D.; Greeley, R.

1977-01-01

Some of the wide variations in the crater-size distributions in lunar photography and in the resulting statistics were interpreted as different degradation rates on different surfaces, different scaling laws in different targets, and a possible population of endogenic craters. These possibilities are reexamined for statistics of 26 different regions. In contrast to most other studies, crater diameters as small as 5 m were measured from enlarged Lunar Orbiter framelets. According to the results of the reported analysis, the different crater distribution types appear to be most consistent with the hypotheses of differential degradation and a superposed crater population. Differential degradation can account for the low level of equilibrium in incompetent materials such as ejecta deposits, mantle deposits, and deep regoliths where scaling law changes and catastrophic processes introduce contradictions with other observations.

Prevalence and correlates of tobacco use among urban adult men in India: a comparison of slum dwellers vs non-slum dwellers.

PubMed

Rooban, T; Joshua, Elizabeth; Rao, Umadevi K; Ranganathan, K

2012-01-01

Tobacco use is reported to be rampant in urban slums in developing countries. Demographical variations in tobacco use between males living in urban slums vs those living in non-slum areas in India has not been reported, and this study was undertaken to address this issue. Secondary data analysis of National Family Health Survey-3 (NFHS-3) was undertaken to study demographical variations in tobacco use between urban slum dwellers and non-slum dwellers in eight Indian cities. Demographic determinants for use of smoking and chewing forms of tobacco in the two groups were analyzed. SPSS version 16.0 (SPSS Inc., IL, USA) was used for statistical analysis. The study population comprised 6887 (41.8%) males from slum areas and 9588 (58.2%) from non-slum areas of eight urban cities. Cigarette/beedi smoking was the commonest form of tobacco use among the study population. Pan masala use was the least common form of smokeless tobacco use, next only to snuff. There was a high statistical significance observed within the various demographic parameter studied in both the slum and non-slum dwelling males in study population. However, on studying the differences between the two groups, it was observed that statistical significance of P≤.001 was observed with age (15-49), secondary education, religion, household structure and marital status. The difference between the two groups in the mean number of cigarettes/beedis smoked was not statistically significant (P=.598). Male slum dwellers are a distinct urban population, whose health needs assessment requires a different approach than that for non-slum dwellers who often can afford the services that an urban Indian city can offer.

Adaptation in Coding by Large Populations of Neurons in the Retina

NASA Astrophysics Data System (ADS)

Ioffe, Mark L.

A comprehensive theory of neural computation requires an understanding of the statistical properties of the neural population code. The focus of this work is the experimental study and theoretical analysis of the statistical properties of neural activity in the tiger salamander retina. This is an accessible yet complex system, for which we control the visual input and record from a substantial portion--greater than a half--of the ganglion cell population generating the spiking output. Our experiments probe adaptation of the retina to visual statistics: a central feature of sensory systems which have to adjust their limited dynamic range to a far larger space of possible inputs. In Chapter 1 we place our work in context with a brief overview of the relevant background. In Chapter 2 we describe the experimental methodology of recording from 100+ ganglion cells in the tiger salamander retina. In Chapter 3 we first present the measurements of adaptation of individual cells to changes in stimulation statistics and then investigate whether pairwise correlations in fluctuations of ganglion cell activity change across different stimulation conditions. We then transition to a study of the population-level probability distribution of the retinal response captured with maximum-entropy models. Convergence of the model inference is presented in Chapter 4. In Chapter 5 we first test the empirical presence of a phase transition in such models fitting the retinal response to different experimental conditions, and then proceed to develop other characterizations which are sensitive to complexity in the interaction matrix. This includes an analysis of the dynamics of sampling at finite temperature, which demonstrates a range of subtle attractor-like properties in the energy landscape. These are largely conserved when ambient illumination is varied 1000-fold, a result not necessarily apparent from the measured low-order statistics of the distribution. Our results form a consistent picture which is discussed at the end of Chapter 5. We conclude with a few future directions related to this thesis.

An ecological genetic delineation of local seed-source provenance for ecological restoration

PubMed Central

Krauss, Siegfried L; Sinclair, Elizabeth A; Bussell, John D; Hobbs, Richard J

2013-01-01

An increasingly important practical application of the analysis of spatial genetic structure within plant species is to help define the extent of local provenance seed collection zones that minimize negative impacts in ecological restoration programs. Here, we derive seed sourcing guidelines from a novel range-wide assessment of spatial genetic structure of 24 populations of Banksia menziesii (Proteaceae), a widely distributed Western Australian tree of significance in local ecological restoration programs. An analysis of molecular variance (AMOVA) of 100 amplified fragment length polymorphism (AFLP) markers revealed significant genetic differentiation among populations (ΦPT = 0.18). Pairwise population genetic dissimilarity was correlated with geographic distance, but not environmental distance derived from 15 climate variables, suggesting overall neutrality of these markers with regard to these climate variables. Nevertheless, Bayesian outlier analysis identified four markers potentially under selection, although these were not correlated with the climate variables. We calculated a global R-statistic using analysis of similarities (ANOSIM) to test the statistical significance of population differentiation and to infer a threshold seed collection zone distance of ∼60 km (all markers) and 100 km (outlier markers) when genetic distance was regressed against geographic distance. Population pairs separated by >60 km were, on average, twice as likely to be significantly genetically differentiated than population pairs separated by <60 km, suggesting that habitat-matched sites within a 30-km radius around a restoration site genetically defines a local provenance seed collection zone for B. menziesii. Our approach is a novel probability-based practical solution for the delineation of a local seed collection zone to minimize negative genetic impacts in ecological restoration. PMID:23919158

Selected papers in the hydrologic sciences, 1986

USGS Publications Warehouse

Subitzky, Seymour

1987-01-01

Water-quality data from long-term (24 years), fixed- station monitoring at the Cape Fear River at Lock 1 near Kelly, N.C., and various measures of basin development are correlated. Subbasin population, number of acres of cropland in the subbasin, number of people employed in manufacturing, and tons of fertilizer applied in the basin are considered as measures of basinwide development activity. Linear correlations show statistically significant posi- tive relations between both population and manufacturing activity and most of the dissolved constituents considered. Negative correlations were found between the acres of harvested cropland and most of the water-quality measures. The amount of fertilizer sold in the subbasin was not statistically related to the water-quality measures considered in this report. The statistical analysis was limited to several commonly used measures of water quality including specific conductance, pH, dissolved solids, several major dissolved ions, and a few nutrients. The major dissolved ions included in the analysis were calcium, sodium, potassium, magnesium, chloride, sulfate, silica, bicarbonate, and fluoride. The nutrients included were dissolved nitrite plus nitrate nitrogen, dissolved ammonia nitrogen, total nitrogen, dissolved phosphates, and total phosphorus. For the chemicals evaluated, manufacturing and population sources are more closely associated with water quality in the Cape Fear River at Lock 1 than are agricultural variables.

Family Early Literacy Practices Questionnaire: A Validation Study for a Spanish-Speaking Population

ERIC Educational Resources Information Center

Lewis, Kandia

2012-01-01

The purpose of the current study was to evaluate the psychometric validity of a Spanish translated version of a family involvement questionnaire (the FELP) using a mixed-methods design. Thus, statistical analyses (i.e., factor analysis, reliability analysis, and item analysis) and qualitative analyses (i.e., focus group data) were assessed.…

Noise exposure-response relationships established from repeated binary observations: Modeling approaches and applications.

PubMed

Schäffer, Beat; Pieren, Reto; Mendolia, Franco; Basner, Mathias; Brink, Mark

2017-05-01

Noise exposure-response relationships are used to estimate the effects of noise on individuals or a population. Such relationships may be derived from independent or repeated binary observations, and modeled by different statistical methods. Depending on the method by which they were established, their application in population risk assessment or estimation of individual responses may yield different results, i.e., predict "weaker" or "stronger" effects. As far as the present body of literature on noise effect studies is concerned, however, the underlying statistical methodology to establish exposure-response relationships has not always been paid sufficient attention. This paper gives an overview on two statistical approaches (subject-specific and population-averaged logistic regression analysis) to establish noise exposure-response relationships from repeated binary observations, and their appropriate applications. The considerations are illustrated with data from three noise effect studies, estimating also the magnitude of differences in results when applying exposure-response relationships derived from the two statistical approaches. Depending on the underlying data set and the probability range of the binary variable it covers, the two approaches yield similar to very different results. The adequate choice of a specific statistical approach and its application in subsequent studies, both depending on the research question, are therefore crucial.

The Analysis of Organizational Diagnosis on Based Six Box Model in Universities

ERIC Educational Resources Information Center

Hamid, Rahimi; Siadat, Sayyed Ali; Reza, Hoveida; Arash, Shahin; Ali, Nasrabadi Hasan; Azizollah, Arbabisarjou

2011-01-01

Purpose: The analysis of organizational diagnosis on based six box model at universities. Research method: Research method was descriptive-survey. Statistical population consisted of 1544 faculty members of universities which through random strafed sampling method 218 persons were chosen as the sample. Research Instrument were organizational…

Assessment of facial golden proportions among central Indian population.

PubMed

Saurabh, Rathore; Piyush, Bolya; Sourabh, Bhatt; Preeti, Ojha; Trivedi, Rutvik; Vishnoi, Pradeep

2016-12-01

This study aimed to identify and establish the facial and smile proportions in young adults and to compare the results with ideal or divine proportions, compare the proportions of males and females included in our study population and compare them with those established for Caucasian and Japanese populations. Two hundred participants (164 females, 36 males) with Angle's class I malocclusion (M.O). and well-balanced faces were selected and photographed in the frontal repose position. Analysis was done in Adobe Photoshop software. Statistical analysis was done using the Statistical Package for the Social Sciences version 17.0. (IBM Corporation Armonk, New York, United States). Results suggested that females are more near to ideal ratios and males are more deviated from the ideal ratios. The proportions of males and females were not considerably different from each other. In Indian population, upper 3 rd facial height (TR-LC) was increased and mid-face height (LC-LN) was decreased; in lower 3 rd of the face, LN-CH was slightly increased in comparison to CH-ME. In facial widths, outer canthal width (LC-LC) was greater in the Indian population and mouth width (CH-CH) was normal. When compared with Indian population, Japanese participants had wider noses, outer canthal distance, and bitemporal width. It was concluded that significant difference was found between the proportions of the Indian population and ideal ratio. When Indian population was compared with Japanese and Caucasian populations, some parameters of facial proportions showed significant difference, which leads to the need for establishing standardized norms for various facial proportions in Indian population.

How Close Do We Live to Water? A Global Analysis of Population Distance to Freshwater Bodies

PubMed Central

Kummu, Matti; de Moel, Hans; Ward, Philip J.; Varis, Olli

2011-01-01

Traditionally, people have inhabited places with ready access to fresh water. Today, over 50% of the global population lives in urban areas, and water can be directed via tens of kilometres of pipelines. Still, however, a large part of the world's population is directly dependent on access to natural freshwater sources. So how are inhabited places related to the location of freshwater bodies today? We present a high-resolution global analysis of how close present-day populations live to surface freshwater. We aim to increase the understanding of the relationship between inhabited places, distance to surface freshwater bodies, and climatic characteristics in different climate zones and administrative regions. Our results show that over 50% of the world's population lives closer than 3 km to a surface freshwater body, and only 10% of the population lives further than 10 km away. There are, however, remarkable differences between administrative regions and climatic zones. Populations in Australia, Asia, and Europe live closest to water. Although populations in arid zones live furthest away from freshwater bodies in absolute terms, relatively speaking they live closest to water considering the limited number of freshwater bodies in those areas. Population distributions in arid zones show statistically significant relationships with a combination of climatic factors and distance to water, whilst in other zones there is no statistically significant relationship with distance to water. Global studies on development and climate adaptation can benefit from an improved understanding of these relationships between human populations and the distance to fresh water. PMID:21687675

Regional analysis of population trajectories from the North American Breeding Bird Survey

USGS Publications Warehouse

Sauer, J.R.; Link, W.A.; Helbig, Andreas J.; Flade, Martin

1999-01-01

The North American Breeding Bird Survey (BBS) was started in 1966, and provides information on population change and distribution for most of the birds in North America. The geographic extent of the survey, and the logistical compromises needed to survey such a large area, present many challenges for estimation from BBS data. In this paper, we describe the survey and discuss some of the limitations of the survey design and implementation. Analysis of the survey has evolved over time as new statistical methods and insights into the analysis of count data are developed. Survey results and analysis tools for the BBS are now available over intemet; we present new methods that use generalized linear models for estimation of population change and empirical Bayes procedures for regional summaries.

Environmental justice assessment for transportation : risk analysis

DOT National Transportation Integrated Search

1999-04-01

This paper presents methods of comparing populations and their racial/ethnic compositions using tabulations, histograms, and Chi Squared tests for statistical significance of differences found. Two examples of these methods are presented: comparison ...

Statistical significance of trace evidence matches using independent physicochemical measurements

NASA Astrophysics Data System (ADS)

Almirall, Jose R.; Cole, Michael; Furton, Kenneth G.; Gettinby, George

1997-02-01

A statistical approach to the significance of glass evidence is proposed using independent physicochemical measurements and chemometrics. Traditional interpretation of the significance of trace evidence matches or exclusions relies on qualitative descriptors such as 'indistinguishable from,' 'consistent with,' 'similar to' etc. By performing physical and chemical measurements with are independent of one another, the significance of object exclusions or matches can be evaluated statistically. One of the problems with this approach is that the human brain is excellent at recognizing and classifying patterns and shapes but performs less well when that object is represented by a numerical list of attributes. Chemometrics can be employed to group similar objects using clustering algorithms and provide statistical significance in a quantitative manner. This approach is enhanced when population databases exist or can be created and the data in question can be evaluated given these databases. Since the selection of the variables used and their pre-processing can greatly influence the outcome, several different methods could be employed in order to obtain a more complete picture of the information contained in the data. Presently, we report on the analysis of glass samples using refractive index measurements and the quantitative analysis of the concentrations of the metals: Mg, Al, Ca, Fe, Mn, Ba, Sr, Ti and Zr. The extension of this general approach to fiber and paint comparisons also is discussed. This statistical approach should not replace the current interpretative approaches to trace evidence matches or exclusions but rather yields an additional quantitative measure. The lack of sufficient general population databases containing the needed physicochemical measurements and the potential for confusion arising from statistical analysis currently hamper this approach and ways of overcoming these obstacles are presented.

Statistical Estimation of Orbital Debris Populations with a Spectrum of Object Size

NASA Technical Reports Server (NTRS)

Xu, Y. -l; Horstman, M.; Krisko, P. H.; Liou, J. -C; Matney, M.; Stansbery, E. G.; Stokely, C. L.; Whitlock, D.

2008-01-01

Orbital debris is a real concern for the safe operations of satellites. In general, the hazard of debris impact is a function of the size and spatial distributions of the debris populations. To describe and characterize the debris environment as reliably as possible, the current NASA Orbital Debris Engineering Model (ORDEM2000) is being upgraded to a new version based on new and better quality data. The data-driven ORDEM model covers a wide range of object sizes from 10 microns to greater than 1 meter. This paper reviews the statistical process for the estimation of the debris populations in the new ORDEM upgrade, and discusses the representation of large-size (greater than or equal to 1 m and greater than or equal to 10 cm) populations by SSN catalog objects and the validation of the statistical approach. Also, it presents results for the populations with sizes of greater than or equal to 3.3 cm, greater than or equal to 1 cm, greater than or equal to 100 micrometers, and greater than or equal to 10 micrometers. The orbital debris populations used in the new version of ORDEM are inferred from data based upon appropriate reference (or benchmark) populations instead of the binning of the multi-dimensional orbital-element space. This paper describes all of the major steps used in the population-inference procedure for each size-range. Detailed discussions on data analysis, parameter definition, the correlation between parameters and data, and uncertainty assessment are included.

DHLAS: A web-based information system for statistical genetic analysis of HLA population data.

PubMed

Thriskos, P; Zintzaras, E; Germenis, A

2007-03-01

DHLAS (database HLA system) is a user-friendly, web-based information system for the analysis of human leukocyte antigens (HLA) data from population studies. DHLAS has been developed using JAVA and the R system, it runs on a Java Virtual Machine and its user-interface is web-based powered by the servlet engine TOMCAT. It utilizes STRUTS, a Model-View-Controller framework and uses several GNU packages to perform several of its tasks. The database engine it relies upon for fast access is MySQL, but others can be used a well. The system estimates metrics, performs statistical testing and produces graphs required for HLA population studies: (i) Hardy-Weinberg equilibrium (calculated using both asymptotic and exact tests), (ii) genetics distances (Euclidian or Nei), (iii) phylogenetic trees using the unweighted pair group method with averages and neigbor-joining method, (iv) linkage disequilibrium (pairwise and overall, including variance estimations), (v) haplotype frequencies (estimate using the expectation-maximization algorithm) and (vi) discriminant analysis. The main merit of DHLAS is the incorporation of a database, thus, the data can be stored and manipulated along with integrated genetic data analysis procedures. In addition, it has an open architecture allowing the inclusion of other functions and procedures.

Apolipoprotein E gene polymorphism and Alzheimer's disease in Chinese population: a meta-analysis

NASA Astrophysics Data System (ADS)

Liu, Mengying; Bian, Chen; Zhang, Jiqiang; Wen, Feng

2014-03-01

The relationship between Apolipoprotein E (ApoE) genotype and the risk of Alzheimer's disease (AD) is relatively well established in Caucasians, but less established in other ethnicities. To examine the association between ApoE polymorphism and the onset of AD in Chinese population, we searched the commonly used electronic databases between January 2000 and November 2013 for relevant studies. Total 20 studies, including 1576 cases and 1741 controls, were retrieved. The results showed statistically significant positive association between risk factor ɛ4 allele carriers and AD in Chinese population (OR = 3.93, 95% CI = 3.37-4.58, P < 0.00001). Genotype ApoE ɛ4/ɛ4 and ɛ4/ɛ3 have statistically significant association with AD as well (ɛ4/ɛ4: OR = 11.76, 95% CI = 6.38-21.47, P < 0.00001; ɛ4/ɛ3: OR = 3.08, 95% CI = 2.57-3.69, P < 0.00001). Furthermore, the frequency of the ApoE ɛ3 is lower in AD than that in the health controls, and the difference of ɛ3 allele is also statistically significant (OR = 0.42, 95% CI = 0.37-0.47, P < 0.00001). No significant heterogeneity was observed among all studies. This meta-analysis suggests that the subject with at least one ApoE ɛ4 allele has higher risk suffering from AD than controls in Chinese population. The results also provide a support for the protection effect of ApoE ɛ3 allele in developing AD.

GUIDANCE FOR STATISTICAL DETERMINATION OF APPROPRIATE PERCENT MINORITY AND PERCENT POVERTY DISTRIBUTIONAL CUTOFF VALUES USING CENSUS DATA FOR AND EPA REGION II ENVIRONMENTAL JUSTICE PROJECT

EPA Science Inventory

The purpose of this report is to assist Region H by providing a statistical analysis identifying the areas with minority and below poverty populations known as "Community of Concern" (COC). The aim was to find a cutoff value as a threshold to identify a COC using demographic data...

A robust and efficient statistical method for genetic association studies using case and control samples from multiple cohorts

PubMed Central

2013-01-01

Background The theoretical basis of genome-wide association studies (GWAS) is statistical inference of linkage disequilibrium (LD) between any polymorphic marker and a putative disease locus. Most methods widely implemented for such analyses are vulnerable to several key demographic factors and deliver a poor statistical power for detecting genuine associations and also a high false positive rate. Here, we present a likelihood-based statistical approach that accounts properly for non-random nature of case–control samples in regard of genotypic distribution at the loci in populations under study and confers flexibility to test for genetic association in presence of different confounding factors such as population structure, non-randomness of samples etc. Results We implemented this novel method together with several popular methods in the literature of GWAS, to re-analyze recently published Parkinson’s disease (PD) case–control samples. The real data analysis and computer simulation show that the new method confers not only significantly improved statistical power for detecting the associations but also robustness to the difficulties stemmed from non-randomly sampling and genetic structures when compared to its rivals. In particular, the new method detected 44 significant SNPs within 25 chromosomal regions of size < 1 Mb but only 6 SNPs in two of these regions were previously detected by the trend test based methods. It discovered two SNPs located 1.18 Mb and 0.18 Mb from the PD candidates, FGF20 and PARK8, without invoking false positive risk. Conclusions We developed a novel likelihood-based method which provides adequate estimation of LD and other population model parameters by using case and control samples, the ease in integration of these samples from multiple genetically divergent populations and thus confers statistically robust and powerful analyses of GWAS. On basis of simulation studies and analysis of real datasets, we demonstrated significant improvement of the new method over the non-parametric trend test, which is the most popularly implemented in the literature of GWAS. PMID:23394771

[Population genetics of the inhabitants of Northern European USSR. II. Blood group distribution and antropogenetic characteristics in 6 villages in Archangel Oblast].

PubMed

Revazov, A A; Pasekov, V P; Lukasheva, I D

1975-01-01

The paper deals with the distribution of genetic markers (systems ABO, MN, Rh (D), Hp, PTC) and a number of demographic (folding of arms, hand clasping, tongue rolling, right- and left-handedness, of the type of ear lobe, of the types of dermatoglyphic patterns) in the inhabitants of 6 villages in the Mezen District of the Archangelsk Region of the RSFSR (river Peosa basin). The data presented in this work were obtained in the course of examination of over 800 persons. Differences in the interpretation of the results of generally adopted methods of statistical analysis of samples from small populations are discussed. Among the systems analysed in one third of all the cases there was a statistically significant deviation from Hardy-Weinberg's ratios. For the MN blood groups and haptoglobins this was caused by the excess of heterozygotes. The test of Hardy--Weinberg's ratios at the level of two-loci phenotypes revealed no statistically significant deviations either in separate villages or in all the villages taken together. The analysis of heterogeneity with respect to markers inherited according to Mendel's law revealed statistically significant differences between villages in all the systems except haptoglobins. A considerable heterogeneity in the distribution of family names, the frequencies of some of them varying from village to village from 0 to 90%. Statistically significant differences between villages were shown for all the anthropogenetic characters except arm folding, hand clasping and right-left-handedness. Considering the uniformity of the environmental pressure in the region examined, the heterogeneity of the population studied is apparently associated with a random genetic differentiation (genetic drift) and, possibly, with the effect of the progenitor.

Neandertal admixture in Eurasia confirmed by maximum-likelihood analysis of three genomes.

PubMed

Lohse, Konrad; Frantz, Laurent A F

2014-04-01

Although there has been much interest in estimating histories of divergence and admixture from genomic data, it has proved difficult to distinguish recent admixture from long-term structure in the ancestral population. Thus, recent genome-wide analyses based on summary statistics have sparked controversy about the possibility of interbreeding between Neandertals and modern humans in Eurasia. Here we derive the probability of full mutational configurations in nonrecombining sequence blocks under both admixture and ancestral structure scenarios. Dividing the genome into short blocks gives an efficient way to compute maximum-likelihood estimates of parameters. We apply this likelihood scheme to triplets of human and Neandertal genomes and compare the relative support for a model of admixture from Neandertals into Eurasian populations after their expansion out of Africa against a history of persistent structure in their common ancestral population in Africa. Our analysis allows us to conclusively reject a model of ancestral structure in Africa and instead reveals strong support for Neandertal admixture in Eurasia at a higher rate (3.4-7.3%) than suggested previously. Using analysis and simulations we show that our inference is more powerful than previous summary statistics and robust to realistic levels of recombination.

Neandertal Admixture in Eurasia Confirmed by Maximum-Likelihood Analysis of Three Genomes

PubMed Central

Lohse, Konrad; Frantz, Laurent A. F.

2014-01-01

Although there has been much interest in estimating histories of divergence and admixture from genomic data, it has proved difficult to distinguish recent admixture from long-term structure in the ancestral population. Thus, recent genome-wide analyses based on summary statistics have sparked controversy about the possibility of interbreeding between Neandertals and modern humans in Eurasia. Here we derive the probability of full mutational configurations in nonrecombining sequence blocks under both admixture and ancestral structure scenarios. Dividing the genome into short blocks gives an efficient way to compute maximum-likelihood estimates of parameters. We apply this likelihood scheme to triplets of human and Neandertal genomes and compare the relative support for a model of admixture from Neandertals into Eurasian populations after their expansion out of Africa against a history of persistent structure in their common ancestral population in Africa. Our analysis allows us to conclusively reject a model of ancestral structure in Africa and instead reveals strong support for Neandertal admixture in Eurasia at a higher rate (3.4−7.3%) than suggested previously. Using analysis and simulations we show that our inference is more powerful than previous summary statistics and robust to realistic levels of recombination. PMID:24532731

Face shape differs in phylogenetically related populations.

PubMed

Hopman, Saskia M J; Merks, Johannes H M; Suttie, Michael; Hennekam, Raoul C M; Hammond, Peter

2014-11-01

3D analysis of facial morphology has delineated facial phenotypes in many medical conditions and detected fine grained differences between typical and atypical patients to inform genotype-phenotype studies. Next-generation sequencing techniques have enabled extremely detailed genotype-phenotype correlative analysis. Such comparisons typically employ control groups matched for age, sex and ethnicity and the distinction between ethnic categories in genotype-phenotype studies has been widely debated. The phylogenetic tree based on genetic polymorphism studies divides the world population into nine subpopulations. Here we show statistically significant face shape differences between two European Caucasian populations of close phylogenetic and geographic proximity from the UK and The Netherlands. The average face shape differences between the Dutch and UK cohorts were visualised in dynamic morphs and signature heat maps, and quantified for their statistical significance using both conventional anthropometry and state of the art dense surface modelling techniques. Our results demonstrate significant differences between Dutch and UK face shape. Other studies have shown that genetic variants influence normal facial variation. Thus, face shape difference between populations could reflect underlying genetic difference. This should be taken into account in genotype-phenotype studies and we recommend that in those studies reference groups be established in the same population as the individuals who form the subject of the study.

Statistical testing of association between menstruation and migraine.

PubMed

Barra, Mathias; Dahl, Fredrik A; Vetvik, Kjersti G

2015-02-01

To repair and refine a previously proposed method for statistical analysis of association between migraine and menstruation. Menstrually related migraine (MRM) affects about 20% of female migraineurs in the general population. The exact pathophysiological link from menstruation to migraine is hypothesized to be through fluctuations in female reproductive hormones, but the exact mechanisms remain unknown. Therefore, the main diagnostic criterion today is concurrency of migraine attacks with menstruation. Methods aiming to exclude spurious associations are wanted, so that further research into these mechanisms can be performed on a population with a true association. The statistical method is based on a simple two-parameter null model of MRM (which allows for simulation modeling), and Fisher's exact test (with mid-p correction) applied to standard 2 × 2 contingency tables derived from the patients' headache diaries. Our method is a corrected version of a previously published flawed framework. To our best knowledge, no other published methods for establishing a menstruation-migraine association by statistical means exist today. The probabilistic methodology shows good performance when subjected to receiver operator characteristic curve analysis. Quick reference cutoff values for the clinical setting were tabulated for assessing association given a patient's headache history. In this paper, we correct a proposed method for establishing association between menstruation and migraine by statistical methods. We conclude that the proposed standard of 3-cycle observations prior to setting an MRM diagnosis should be extended with at least one perimenstrual window to obtain sufficient information for statistical processing. © 2014 American Headache Society.

Statistical shape analysis using 3D Poisson equation--A quantitatively validated approach.

PubMed

Gao, Yi; Bouix, Sylvain

2016-05-01

Statistical shape analysis has been an important area of research with applications in biology, anatomy, neuroscience, agriculture, paleontology, etc. Unfortunately, the proposed methods are rarely quantitatively evaluated, and as shown in recent studies, when they are evaluated, significant discrepancies exist in their outputs. In this work, we concentrate on the problem of finding the consistent location of deformation between two population of shapes. We propose a new shape analysis algorithm along with a framework to perform a quantitative evaluation of its performance. Specifically, the algorithm constructs a Signed Poisson Map (SPoM) by solving two Poisson equations on the volumetric shapes of arbitrary topology, and statistical analysis is then carried out on the SPoMs. The method is quantitatively evaluated on synthetic shapes and applied on real shape data sets in brain structures. Copyright © 2016 Elsevier B.V. All rights reserved.

An issue of literacy on pediatric arterial hypertension

NASA Astrophysics Data System (ADS)

Teodoro, M. Filomena; Romana, Andreia; Simão, Carla

2017-11-01

Arterial hypertension in pediatric age is a public health problem, whose prevalence has increased significantly over time. Pediatric arterial hypertension (PAH) is under-diagnosed in most cases, a highly prevalent disease, appears without notice with multiple consequences on the children's health and future adults. Children caregivers and close family must know the PAH existence, the negative consequences associated with it, the risk factors and, finally, must do prevention. In [12, 13] can be found a statistical data analysis using a simpler questionnaire introduced in [4] under the aim of a preliminary study about PAH caregivers acquaintance. A continuation of such analysis is detailed in [14]. An extension of such questionnaire was built and applied to a distinct population and it was filled online. The statistical approach is partially reproduced in the present work. Some statistical models were estimated using several approaches, namely multivariate analysis (factorial analysis), also adequate methods to analyze the kind of data in study.

A Nonparametric Test for Homogeneity of Variances: Application to GPAs of Students across Academic Majors

ERIC Educational Resources Information Center

Bakir, Saad T.

2010-01-01

We propose a nonparametric (or distribution-free) procedure for testing the equality of several population variances (or scale parameters). The proposed test is a modification of Bakir's (1989, Commun. Statist., Simul-Comp., 18, 757-775) analysis of means by ranks (ANOMR) procedure for testing the equality of several population means. A proof is…

Barcoding T Cell Calcium Response Diversity with Methods for Automated and Accurate Analysis of Cell Signals (MAAACS)

PubMed Central

Sergé, Arnauld; Bernard, Anne-Marie; Phélipot, Marie-Claire; Bertaux, Nicolas; Fallet, Mathieu; Grenot, Pierre; Marguet, Didier; He, Hai-Tao; Hamon, Yannick

2013-01-01

We introduce a series of experimental procedures enabling sensitive calcium monitoring in T cell populations by confocal video-microscopy. Tracking and post-acquisition analysis was performed using Methods for Automated and Accurate Analysis of Cell Signals (MAAACS), a fully customized program that associates a high throughput tracking algorithm, an intuitive reconnection routine and a statistical platform to provide, at a glance, the calcium barcode of a population of individual T-cells. Combined with a sensitive calcium probe, this method allowed us to unravel the heterogeneity in shape and intensity of the calcium response in T cell populations and especially in naive T cells, which display intracellular calcium oscillations upon stimulation by antigen presenting cells. PMID:24086124

Shoulder strength value differences between genders and age groups.

PubMed

Balcells-Diaz, Eudald; Daunis-I-Estadella, Pepus

2018-03-01

The strength of a normal shoulder differs according to gender and decreases with age. Therefore, the Constant score, which is a shoulder function measurement tool that allocates 25% of the final score to strength, differs from the absolute values but likely reflects a normal shoulder. To compare group results, a normalized Constant score is needed, and the first step to achieving normalization involves statistically establishing the gender differences and age-related decline. In this investigation, we sought to verify the gender difference and age-related decline in strength. We obtained a randomized representative sample of the general population in a small to medium-sized Spanish city. We then invited this population to participate in our study, and we measured their shoulder strength. We performed a statistical analysis with a power of 80% and a P value < .05. We observed a statistically significant difference between the genders and a statistically significant decline with age. To the best of our knowledge, this is the first investigation to study a representative sample of the general population from which conclusions can be drawn regarding Constant score normalization. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Evaluation of Solid Rocket Motor Component Data Using a Commercially Available Statistical Software Package

NASA Technical Reports Server (NTRS)

Stefanski, Philip L.

2015-01-01

Commercially available software packages today allow users to quickly perform the routine evaluations of (1) descriptive statistics to numerically and graphically summarize both sample and population data, (2) inferential statistics that draws conclusions about a given population from samples taken of it, (3) probability determinations that can be used to generate estimates of reliability allowables, and finally (4) the setup of designed experiments and analysis of their data to identify significant material and process characteristics for application in both product manufacturing and performance enhancement. This paper presents examples of analysis and experimental design work that has been conducted using Statgraphics®(Registered Trademark) statistical software to obtain useful information with regard to solid rocket motor propellants and internal insulation material. Data were obtained from a number of programs (Shuttle, Constellation, and Space Launch System) and sources that include solid propellant burn rate strands, tensile specimens, sub-scale test motors, full-scale operational motors, rubber insulation specimens, and sub-scale rubber insulation analog samples. Besides facilitating the experimental design process to yield meaningful results, statistical software has demonstrated its ability to quickly perform complex data analyses and yield significant findings that might otherwise have gone unnoticed. One caveat to these successes is that useful results not only derive from the inherent power of the software package, but also from the skill and understanding of the data analyst.

Resilience of aging populations after devastating earthquake event and its determinants - A case study of the Chi-Chi earthquake in Taiwan

NASA Astrophysics Data System (ADS)

Hung, Chih-Hsuan; Hung, Hung-Chih

2016-04-01

1.Background Major portions of urban areas in Asia are highly exposed and vulnerable to devastating earthquakes. Many studies identify ways to reduce earthquake risk by concentrating more on building resilience for the particularly vulnerable populations. By 2020, as the United Nations' warning, many Asian countries would become 'super-aged societies', such as Taiwan. However, local authorities rarely use resilience approach to frame earthquake disaster risk management and land use strategies. The empirically-based research about the resilience of aging populations has also received relatively little attention. Thus, a challenge arisen for decision-makers is how to enhance resilience of aging populations within the context of risk reduction. This study aims to improve the understanding of the resilience of aging populations and its changes over time in the aftermath of a destructive earthquake at the local level. A novel methodology is proposed to assess the resilience of aging populations and to characterize their changes of spatial distribution patterns, as well as to examine their determinants. 2.Methods and data An indicator-based assessment framework is constructed with the goal of identifying composite indicators (including before, during and after a disaster) that could serve as proxies for attributes of the resilience of aging populations. Using the recovery process of the Chi-Chi earthquake struck central Taiwan in 1999 as a case study, we applied a method combined a geographical information system (GIS)-based spatial statistics technique and cluster analysis to test the extent of which the resilience of aging populations is spatially autocorrelated throughout the central Taiwan, and to explain why clustering of resilient areas occurs in specific locations. Furthermore, to scrutinize the affecting factors of resilience, we develop an aging population resilience model (APRM) based on existing resilience theory. Using the APRM, we applied a multivariate regression analysis to identify and examine how various factors connect to the resilience of aging populations. To illustrate the proposed methodology, the study collected data on the resilience attributes, the disaster impacts and damages due to the Chi-Chi earthquake. The data were offered by the National Science and Technology Center for Disaster Reduction, Taiwan, as well as collected from the National Land Use Investigation, official census statistics and questionnaire surveys. 3.Results Integrating cluster analysis with GIS-based spatial statistical analysis, the resilience of aging populations were divided into five clusters of distribution patterns over the 10 years after the Chi-Chi earthquake. It shows that both population and elderly distributions were highly heterogeneous and spatial correlated across the study areas. We also demonstrated the 'hot spots' areas of the highly concentrated aging population across central Taiwan. Results of regression analysis disclosed the major factors that caused low resilience and changes of aging population distributions over time. These factors included the levels of seismic damage, infrastructure investments, as well as the land-use and socioeconomic attributes associated with the disaster areas. Finally, our findings provide stakeholders and policy-makers with better adaptive options to design and synthesize appropriate patchworks of planning measures for different types of resilience areas to reduce earthquake disaster risk.

Accounting for rate instability and spatial patterns in the boundary analysis of cancer mortality maps

PubMed Central

Goovaerts, Pierre

2006-01-01

Boundary analysis of cancer maps may highlight areas where causative exposures change through geographic space, the presence of local populations with distinct cancer incidences, or the impact of different cancer control methods. Too often, such analysis ignores the spatial pattern of incidence or mortality rates and overlooks the fact that rates computed from sparsely populated geographic entities can be very unreliable. This paper proposes a new methodology that accounts for the uncertainty and spatial correlation of rate data in the detection of significant edges between adjacent entities or polygons. Poisson kriging is first used to estimate the risk value and the associated standard error within each polygon, accounting for the population size and the risk semivariogram computed from raw rates. The boundary statistic is then defined as half the absolute difference between kriged risks. Its reference distribution, under the null hypothesis of no boundary, is derived through the generation of multiple realizations of the spatial distribution of cancer risk values. This paper presents three types of neutral models generated using methods of increasing complexity: the common random shuffle of estimated risk values, a spatial re-ordering of these risks, or p-field simulation that accounts for the population size within each polygon. The approach is illustrated using age-adjusted pancreatic cancer mortality rates for white females in 295 US counties of the Northeast (1970–1994). Simulation studies demonstrate that Poisson kriging yields more accurate estimates of the cancer risk and how its value changes between polygons (i.e. boundary statistic), relatively to the use of raw rates or local empirical Bayes smoother. When used in conjunction with spatial neutral models generated by p-field simulation, the boundary analysis based on Poisson kriging estimates minimizes the proportion of type I errors (i.e. edges wrongly declared significant) while the frequency of these errors is predicted well by the p-value of the statistical test. PMID:19023455

An ecological study of cancer incidence in Port Hope, Ontario from 1992 to 2007.

PubMed

Chen, Jing; Moir, Deborah; Lane, Rachel; Thompson, Patsy

2013-03-01

A plant processing radium and uranium ores has been operating in the town of Port Hope since 1932. Given the nuclear industry located in the community and ongoing public health concerns, cancer incidence rates in Port Hope were studied for a recent 16 year period (1992-2007) for continued periodic cancer incidence surveillance of the community. The cancer incidence in the local community for all cancers combined was similar to the Ontario population, health regions with similar socio-economic characteristics in Ontario and in Canada, and the Canadian population. No statistically significant differences in childhood cancer, leukaemia or other radiosensitive cancer incidence were observed, with the exception of statistically significant elevated lung cancer incidence among women. However, the statistical significance was reduced or disappeared when the comparison was made to populations with similar socio-economic characteristics. These findings are consistent with previous ecological, case-control and cohort studies conducted in Port Hope, environmental assessments, and epidemiological studies conducted elsewhere on populations living around similar facilities or exposed to similar environmental contaminants. Although the current study covered an extended period of time, the power to detect risk at the sub-regional level of analysis was limited since the Port Hope population is small (16,500). The study nevertheless indicated that large differences in cancer incidence are not occurring in Port Hope compared to other similar communities and the general population.

Regression equations for sex and population detection using the lip print pattern among Egyptian and Malaysian adult.

PubMed

Abdel Aziz, Manal H; Badr El Dine, Fatma M M; Saeed, Nourhan M M

2016-11-01

Identification of sex and ethnicity has always been a challenge in the fields of forensic medicine and criminal investigations. Fingerprinting and DNA comparisons are probably the most common techniques used in this context. However, since they cannot always be used, it is necessary to apply different and less known techniques such as lip prints. Is to study the pattern of lip print in Egyptian and Malaysian populations and its relation to sex and populations difference. Also, to develop equations for sex and populations detection using lip print pattern by different populations (Egyptian and Malaysian). The sample comprised of 120 adults volunteers divided into two ethnic groups; sixty adult Egyptians (30 males and 30 females) and sixty adult Malaysians (30 males and 30 females). The lip prints were collected on a white paper. Each lip print was divided into four compartments and were classified and scored according to Suzuki and Tsuchihashi classification. Data were statistically analyzed. The results showed that type III lip print pattern (intersected grooves) was the predominant type in both the Egyptian and Malaysian populations. Type II and III were the most frequent in Egyptian males (28.3% each), while in Egyptian females type III pattern was predominant (46.7%). As regards Malaysian males, type III lip print pattern was the predominant one (41.7%), while type II lip print pattern was predominant (30.8%) in Malaysian females. Statistical analysis of different quadrants showed significant differences between males and females in the Egyptian population in the third and fourth quadrants. On the other hand, significant differences were detected only in the second quadrant between Malaysian males and females. Also, a statistically significant difference was present in the second quadrant between Egyptian and Malaysian males. Using the regression analysis, four regression equations were obtained. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Statistical dynamics of regional populations and economies

NASA Astrophysics Data System (ADS)

Huo, Jie; Wang, Xu-Ming; Hao, Rui; Wang, Peng

Quantitative analysis of human behavior and social development is becoming a hot spot of some interdisciplinary studies. A statistical analysis on the population and GDP of 150 cities in China from 1990 to 2013 is conducted. The result indicates the cumulative probability distribution of the populations and that of the GDPs obeying the shifted power law, respectively. In order to understand these characteristics, a generalized Langevin equation describing variation of population is proposed, which is based on the correlations between population and GDP as well as the random fluctuations of the related factors. The equation is transformed into the Fokker-Plank equation to express the evolution of population distribution. The general solution demonstrates a transition of the distribution from the normal Gaussian distribution to a shifted power law, which suggests a critical point of time at which the transition takes place. The shifted power law distribution in the supercritical situation is qualitatively in accordance with the practical result. The distribution of the GDPs is derived from the well-known Cobb-Douglas production function. The result presents a change, in supercritical situation, from a shifted power law to the Gaussian distribution. This is a surprising result-the regional GDP distribution of our world will be the Gaussian distribution one day in the future. The discussions based on the changing trend of economic growth suggest it will be true. Therefore, these theoretical attempts may draw a historical picture of our society in the aspects of population and economy.

Fumonisin B1 and Risk of Hepatocellular Carcinoma in Two Chinese Cohorts

PubMed Central

Persson, E. Christina; Sewram, Vikash; Evans, Alison A.; London, W. Thomas; Volkwyn, Yvette; Shen, Yen-Ju; Van Zyl, Jacobus A.; Chen, Gang; Lin, Wenyao; Shephard, Gordon S.; Taylor, Philip R.; Fan, Jin-Hu; Dawsey, Sanford M.; Qiao, You-Lin; McGlynn, Katherine A.; Abnet, Christian C.

2011-01-01

Fumonisin B1 (FB1), a mycotoxin that contaminates corn in certain climates, has been demonstrated to cause hepatocellular cancer (HCC) in animal models. Whether a relationship between FB1 and HCC exists in humans is not known. To examine the hypothesis, we conducted case-control studies nested within two large cohorts in China; the Haimen City Cohort and the General Population Study of the Nutritional Intervention Trials cohort in Linxian. In the Haimen City Cohort, nail FB1 levels were determined in 271 HCC cases and 280 controls. In the General Population Nutritional Intervention Trial, nail FB1 levels were determined in 72 HCC cases and 147 controls. In each population, odds ratios and 95% confidence intervals (95%CI) from logistic regression models estimated the association between measurable FB1 and HCC, adjusting for hepatitis B virus infection and other factors. A meta-analysis that included both populations was also conducted. The analysis revealed no statistically significant association between FB1 and HCC in either Haimen City (OR=1.10, 95%CI=0.64–1.89) or in Linxian (OR=1.47, 95%CI=0.70–3.07). Similarly, the pooled meta-analysis showed no statistically significant association between FB1 exposure and HCC (OR=1.22, 95%CI=0.79–1.89). These findings, although somewhat preliminary, do not support an associated between FB1 and HCC. PMID:22142693

Spatio-temporal Genetic Structuring of Leishmania major in Tunisia by Microsatellite Analysis

PubMed Central

Harrabi, Myriam; Bettaieb, Jihène; Ghawar, Wissem; Toumi, Amine; Zaâtour, Amor; Yazidi, Rihab; Chaâbane, Sana; Chalghaf, Bilel; Hide, Mallorie; Bañuls, Anne-Laure; Ben Salah, Afif

2015-01-01

In Tunisia, cases of zoonotic cutaneous leishmaniasis caused by Leishmania major are increasing and spreading from the south-west to new areas in the center. To improve the current knowledge on L. major evolution and population dynamics, we performed multi-locus microsatellite typing of human isolates from Tunisian governorates where the disease is endemic (Gafsa, Kairouan and Sidi Bouzid governorates) and collected during two periods: 1991–1992 and 2008–2012. Analysis (F-statistics and Bayesian model-based approach) of the genotyping results of isolates collected in Sidi Bouzid in 1991–1992 and 2008–2012 shows that, over two decades, in the same area, Leishmania parasites evolved by generating genetically differentiated populations. The genetic patterns of 2008–2012 isolates from the three governorates indicate that L. major populations did not spread gradually from the south to the center of Tunisia, according to a geographical gradient, suggesting that human activities might be the source of the disease expansion. The genotype analysis also suggests previous (Bayesian model-based approach) and current (F-statistics) flows of genotypes between governorates and districts. Human activities as well as reservoir dynamics and the effects of environmental changes could explain how the disease progresses. This study provides new insights into the evolution and spread of L. major in Tunisia that might improve our understanding of the parasite flow between geographically and temporally distinct populations. PMID:26302440

Biostatistics primer: part I.

PubMed

Overholser, Brian R; Sowinski, Kevin M

2007-12-01

Biostatistics is the application of statistics to biologic data. The field of statistics can be broken down into 2 fundamental parts: descriptive and inferential. Descriptive statistics are commonly used to categorize, display, and summarize data. Inferential statistics can be used to make predictions based on a sample obtained from a population or some large body of information. It is these inferences that are used to test specific research hypotheses. This 2-part review will outline important features of descriptive and inferential statistics as they apply to commonly conducted research studies in the biomedical literature. Part 1 in this issue will discuss fundamental topics of statistics and data analysis. Additionally, some of the most commonly used statistical tests found in the biomedical literature will be reviewed in Part 2 in the February 2008 issue.

Finding Groups Using Model-Based Cluster Analysis: Heterogeneous Emotional Self-Regulatory Processes and Heavy Alcohol Use Risk

ERIC Educational Resources Information Center

Mun, Eun Young; von Eye, Alexander; Bates, Marsha E.; Vaschillo, Evgeny G.

2008-01-01

Model-based cluster analysis is a new clustering procedure to investigate population heterogeneity utilizing finite mixture multivariate normal densities. It is an inferentially based, statistically principled procedure that allows comparison of nonnested models using the Bayesian information criterion to compare multiple models and identify the…

An Analysis of Variance Framework for Matrix Sampling.

ERIC Educational Resources Information Center

Sirotnik, Kenneth

Significant cost savings can be achieved with the use of matrix sampling in estimating population parameters from psychometric data. The statistical design is intuitively simple, using the framework of the two-way classification analysis of variance technique. For example, the mean and variance are derived from the performance of a certain grade…

Genetic polymorphisms, forensic efficiency and phylogenetic analysis of 15 autosomal STR loci in the Kazak population of Ili Kazak Autonomous Prefecture, northwestern China.

PubMed

Feng, Chunmei; Wang, Xin; Wang, Xiaolong; Yu, Hao; Zhang, Guohua

2018-03-01

We investigated the frequencies of 15 autosomal STR loci in the Kazak population of the Ili Kazak Autonomous Prefecture with the aim of expanding the available population information in human genetic databases and for forensic DNA analysis. Genetic polymorphisms of 15 autosomal short tandem repeat (STR) loci were analysed in 456 individuals of the Kazak population from Ili Kazakh Autonomous Prefecture, northwestern China. A total of 173 alleles at 15 autosomal STR loci were found; the allele frequencies ranged from 0.5022-0.0011. The combined power of discrimination and exclusion statistics for the 15 STR loci were 0.999 999 999 85 and 0.999 998 800 65, respectively. In addition, phylogenetic analysis involving the Ili Uygur population and other relevant populations was carried out. A neighbour-joining tree and multidimensional scaling plot were generated based on Nei's standard genetic distance. Results of the population comparison indicated that the Ili Uygur population was most closely related genetically to the Uygur populations from other regions in China. These findings are consistent with the historical and geographic backgrounds of these populations.

Ethnic disparities in the risk of colorectal adenomas associated with lipid levels: a retrospective multiethnic study.

PubMed

Davis-Yadley, Ashley H; Lipka, Seth; Shen, Huafeng; Devanney, Valerie; Swarup, Supreeya; Barnowsky, Alex; Silpe, Jeff; Mosdale, Josh; Pan, Qinshi; Fridlyand, Svetlana; Sreeharshan, Suhas; Abraham, Albin; Viswanathan, Prakash; Krishnamachari, Bhuma

2015-03-01

Although data exists showing that uncontrolled lipid levels in white and black patients is associated with colorectal adenomas, there are currently no studies looking only at the Hispanic population. With the rapid increase in the Hispanic population, we aimed to look at their risk of colorectal adenomas in association with lipid levels. We retrospectively analyzed 1473 patients undergoing colonoscopy from 2009 to 2011 at a community hospital. Statistical analysis was performed using Chi-squared for categorical variables and t test for continuous variables with age-, gender-, and race-adjusted odds ratios. Unconditional logistic regression model was used to estimate 95 % confidence intervals (CI). SAS 9.3 software was used to perform all statistical analysis. In our general population, there was an association with elevated triglyceride levels greater than 150 and presence of multiple colorectal adenomas with odds ratio (OR) 1.60 (1.03, 2.48). There was an association with proximal colon adenomas and cholesterol levels between 200 and 239 with OR 1.57 (1.07, 2.30), and low-density lipoprotein (LDL) levels of greater than 130 with OR 1.54 (1.04, 2.30). There was no association between high-density lipoproteins (HDL) levels and colorectal adenomas. The Hispanic population showed no statistical correlation between elevated triglycerides, cholesterol, or LDL with the presence, size, location, or multiplicity of colorectal adenomas. We found a significant correlation between elevated lipid levels and colorectal adenomas in white and black patients; however, there was no such association in the Hispanic population. This finding can possibly be due to environmental factors such as dietary, colonic flora, or genetic susceptibility, which fosters further investigation and research.

Health inequalities among rural and urban population of Eastern Poland in the context of sustainable development.

PubMed

Pantyley, Viktoriya

2017-09-21

The primary goals of the study were a critical analysis of the concepts associated with health from the perspective of sustainable development, and empirical analysis of health and health- related issues among the rural and urban residents of Eastern Poland in the context of the sustainable development of the region. The study was based on the following research methods: a systemic approach, selection and analysis of the literature and statistical data, developing a special questionnaire concerning socio-economic and health inequalities among the population in the studied area, field research with an interview questionnaire conducted on randomly-selected respondents (N=1,103) in randomly selected areas of the Lubelskie, Podkarpackie, Podlaskie and eastern part of Mazowieckie Provinces (with the division between provincial capital cities - county capital cities - other cities - rural areas). The results of statistical surveys in the studied area with the use of chi-square test and contingence quotients indicated a correlation between the state of health and the following independent variables: age, life quality, social position and financial situation (C-Pearson's coefficient over 0,300); a statistically significant yet weak correlation was recorded for gender, household size, place of residence and amount of free time. The conducted analysis proved the existence of a huge gap between state of health of the population in urban and rural areas. In order to eliminate unfavourable differences in the state iof health among the residents of Eastern Poland, and provide equal sustainable development in urban and rural areas of the examined areas, special preventive programmes aimed at the residents of peripheral, marginalized rural areas should be implemented. In these programmes, attention should be paid to preventive measures, early diagnosis of basic civilization and social diseases, and better accessibility to medical services for the residents.

Joint multi-population analysis for genetic linkage of bipolar disorder or "wellness" to chromosome 4p.

PubMed

Visscher, P M; Haley, C S; Ewald, H; Mors, O; Egeland, J; Thiel, B; Ginns, E; Muir, W; Blackwood, D H

2005-02-05

To test the hypothesis that the same genetic loci confer susceptibility to, or protection from, disease in different populations, and that a combined analysis would improve the map resolution of a common susceptibility locus, we analyzed data from three studies that had reported linkage to bipolar disorder in a small region on chromosome 4p. Data sets comprised phenotypic information and genetic marker data on Scottish, Danish, and USA extended pedigrees. Across the three data sets, 913 individuals appeared in the pedigrees, 462 were classified, either as unaffected (323) or affected (139) with unipolar or bipolar disorder. A consensus linkage map was created from 14 microsatellite markers in a 33 cM region. Phenotypic and genetic data were analyzed using a variance component (VC) and allele sharing method. All previously reported elevated test statistics in the region were confirmed with one or both analysis methods, indicating the presence of one or more susceptibility genes to bipolar disorder in the three populations in the studied chromosome segment. When the results from both the VC and allele sharing method were considered, there was strong evidence for a susceptibility locus in the data from Scotland, some evidence in the data from Denmark and relatively less evidence in the data from the USA. The test statistics from the Scottish data set dominated the test statistics from the other studies, and no improved map resolution for a putative genetic locus underlying susceptibility in all three studies was obtained. Studies reporting linkage to the same region require careful scrutiny and preferably joint or meta analysis on the same basis in order to ensure that the results are truly comparable. (c) 2004 Wiley-Liss, Inc.

Prevalence of suicidal ideation and suicide attempts in the general population of China: A meta-Analysis

PubMed Central

CAO, XIAO-LAN; ZHONG, BAO-LIANG; XIANG, YU-TAO; UNGVARI, GABOR S.; LAI, KELLY Y. C.; CHIU, HELEN F. K.; CAINE, ERIC D.

2015-01-01

Objective The objective of this meta-analysis is to estimate the pooled prevalence of suicidal ideation and suicide attempts in the general population of Mainland China. Methods A systematic literature search was conducted via the following databases: PubMed, PsycINFO, MEDLINE, China Journals Full-Text Databases, Chongqing VIP database for Chinese Technical Periodicals and Wan Fang Data. Statistical analysis used the Comprehensive Meta-Analysis program. Results Eight studies met the inclusion criteria for the analysis; five reported on the prevalence of suicidal ideation and seven on that of suicide attempts. The estimated lifetime prevalence figures of suicidal ideation and suicide attempts were 3.9% (95% Confidence interval [CI]: 2.5%–6.0%) and 0.8% (95% CI: 0.7%–0.9%), respectively. The estimated female-male ratio for lifetime prevalence of suicidal ideation and suicide attempts was 1.7 and 2.2, respectively. Only the difference of suicide attempts between the two genders was statistically significant. Conclusion This was the first meta-analysis of the prevalence of suicidal ideation and suicide attempts in the general population of Mainland China. The pooled lifetime prevalence of both suicidal ideation and suicide attempts are relatively low; however, caution is required when assessing these self-report data. Women had a modestly higher prevalence for suicide attempts than men. The frequency for suicidal ideation and suicide attempts in urban regions was similar to those in rural areas. PMID:26060259

Application of statistical shape analysis for the estimation of bone and forensic age using the shapes of the 2nd, 3rd, and 4th cervical vertebrae in a young Japanese population.

PubMed

Rhee, Chang-Hoon; Shin, Sang Min; Choi, Yong-Seok; Yamaguchi, Tetsutaro; Maki, Koutaro; Kim, Yong-Il; Kim, Seong-Sik; Park, Soo-Byung; Son, Woo-Sung

2015-12-01

From computed tomographic images, the dentocentral synchondrosis can be identified in the second cervical vertebra. This can demarcate the border between the odontoid process and the body of the 2nd cervical vertebra and serve as a good model for the prediction of bone and forensic age. Nevertheless, until now, there has been no application of the 2nd cervical vertebra based on the dentocentral synchondrosis. In this study, statistical shape analysis was used to build bone and forensic age estimation regression models. Following the principles of statistical shape analysis and principal components analysis, we used cone-beam computed tomography (CBCT) to evaluate a Japanese population (35 males and 45 females, from 5 to 19 years old). The narrowest prediction intervals among the multivariate regression models were 19.63 for bone age and 2.99 for forensic age. There was no significant difference between form space and shape space in the bone and forensic age estimation models. However, for gender comparison, the bone and forensic age estimation models for males had the higher explanatory power. This study derived an improved objective and quantitative method for bone and forensic age estimation based on only the 2nd, 3rd and 4th cervical vertebral shapes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

[New design of the Health Survey of Catalonia (Spain, 2010-2014): a step forward in health planning and evaluation].

PubMed

Alcañiz-Zanón, Manuela; Mompart-Penina, Anna; Guillén-Estany, Montserrat; Medina-Bustos, Antonia; Aragay-Barbany, Josep M; Brugulat-Guiteras, Pilar; Tresserras-Gaju, Ricard

2014-01-01

This article presents the genesis of the Health Survey of Catalonia (Spain, 2010-2014) with its semiannual subsamples and explains the basic characteristics of its multistage sampling design. In comparison with previous surveys, the organizational advantages of this new statistical operation include rapid data availability and the ability to continuously monitor the population. The main benefits are timeliness in the production of indicators and the possibility of introducing new topics through the supplemental questionnaire as a function of needs. Limitations consist of the complexity of the sample design and the lack of longitudinal follow-up of the sample. Suitable sampling weights for each specific subsample are necessary for any statistical analysis of micro-data. Accuracy in the analysis of territorial disaggregation or population subgroups increases if annual samples are accumulated. Copyright © 2013 SESPAS. Published by Elsevier Espana. All rights reserved.

Evolution in Cloud Population Statistics of the MJO: From AMIE Field Observations to Global-Cloud Permitting Models Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kollias, Pavlos

This is a multi-institutional, collaborative project using a three-tier modeling approach to bridge field observations and global cloud-permitting models, with emphases on cloud population structural evolution through various large-scale environments. Our contribution was in data analysis for the generation of high value cloud and precipitation products and derive cloud statistics for model validation. There are two areas in data analysis that we contributed: the development of a synergistic cloud and precipitation cloud classification that identify different cloud (e.g. shallow cumulus, cirrus) and precipitation types (shallow, deep, convective, stratiform) using profiling ARM observations and the development of a quantitative precipitation ratemore » retrieval algorithm using profiling ARM observations. Similar efforts have been developed in the past for precipitation (weather radars), but not for the millimeter-wavelength (cloud) radar deployed at the ARM sites.« less

Block observations of neighbourhood physical disorder are associated with neighbourhood crime, firearm injuries and deaths, and teen births.

PubMed

Wei, Evelyn; Hipwell, Alison; Pardini, Dustin; Beyers, Jennifer M; Loeber, Rolf

2005-10-01

To provide reliability information for a brief observational measure of physical disorder and determine its relation with neighbourhood level crime and health variables after controlling for census based measures of concentrated poverty and minority concentration. Psychometric analysis of block observation data comprising a brief measure of neighbourhood physical disorder, and cross sectional analysis of neighbourhood physical disorder, neighbourhood crime and birth statistics, and neighbourhood level poverty and minority concentration. Pittsburgh, Pennsylvania, US (2000 population=334 563). Pittsburgh neighbourhoods (n=82) and their residents (as reflected in neighbourhood level statistics). The physical disorder index showed adequate reliability and validity and was associated significantly with rates of crime, firearm injuries and homicides, and teen births, while controlling for concentrated poverty and minority population. This brief measure of neighbourhood physical disorder may help increase our understanding of how community level factors reflect health and crime outcomes.

Two Populations of Sunspots: Differential Rotation

NASA Astrophysics Data System (ADS)

Nagovitsyn, Yu. A.; Pevtsov, A. A.; Osipova, A. A.

2018-03-01

To investigate the differential rotation of sunspot groups using the Greenwich data, we propose an approach based on a statistical analysis of the histograms of particular longitudinal velocities in different latitude intervals. The general statistical velocity distributions for all such intervals are shown to be described by two rather than one normal distribution, so that two fundamental rotation modes exist simultaneously: fast and slow. The differentiality of rotation for the modes is the same: the coefficient at sin2 in Faye's law is 2.87-2.88 deg/day, while the equatorial rotation rates differ significantly, 0.27 deg/day. On the other hand, an analysis of the longitudinal velocities for the previously revealed two differing populations of sunspot groups has shown that small short-lived groups (SSGs) are associated with the fast rotation mode, while large long-lived groups (LLGs) are associated with both fast and slow modes. The results obtained not only suggest a real physical difference between the two populations of sunspots but also give new empirical data for the development of a dynamo theory, in particular, for the theory of a spatially distributed dynamo.

Predicting the Ability of Marine Mammal Populations to Compensate for Behavioral Disturbances

DTIC Science & Technology

2015-09-30

approaches, including simple theoretical models as well as statistical analysis of data rich conditions. Building on models developed for PCoD [2,3], we...conditions is population trajectory most likely to be affected (the central aim of PCoD ). For the revised model presented here, we include a population...averaged condition individuals (here used as a proxy for individual health as defined in PCoD ), and E is the quality of the environment in which the

On the implications of the classical ergodic theorems: analysis of developmental processes has to focus on intra-individual variation.

PubMed

Molenaar, Peter C M

2008-01-01

It is argued that general mathematical-statistical theorems imply that standard statistical analysis techniques of inter-individual variation are invalid to investigate developmental processes. Developmental processes have to be analyzed at the level of individual subjects, using time series data characterizing the patterns of intra-individual variation. It is shown that standard statistical techniques based on the analysis of inter-individual variation appear to be insensitive to the presence of arbitrary large degrees of inter-individual heterogeneity in the population. An important class of nonlinear epigenetic models of neural growth is described which can explain the occurrence of such heterogeneity in brain structures and behavior. Links with models of developmental instability are discussed. A simulation study based on a chaotic growth model illustrates the invalidity of standard analysis of inter-individual variation, whereas time series analysis of intra-individual variation is able to recover the true state of affairs. (c) 2007 Wiley Periodicals, Inc.

Detecting concerted demographic response across community assemblages using hierarchical approximate Bayesian computation.

PubMed

Chan, Yvonne L; Schanzenbach, David; Hickerson, Michael J

2014-09-01

Methods that integrate population-level sampling from multiple taxa into a single community-level analysis are an essential addition to the comparative phylogeographic toolkit. Detecting how species within communities have demographically tracked each other in space and time is important for understanding the effects of future climate and landscape changes and the resulting acceleration of extinctions, biological invasions, and potential surges in adaptive evolution. Here, we present a statistical framework for such an analysis based on hierarchical approximate Bayesian computation (hABC) with the goal of detecting concerted demographic histories across an ecological assemblage. Our method combines population genetic data sets from multiple taxa into a single analysis to estimate: 1) the proportion of a community sample that demographically expanded in a temporally clustered pulse and 2) when the pulse occurred. To validate the accuracy and utility of this new approach, we use simulation cross-validation experiments and subsequently analyze an empirical data set of 32 avian populations from Australia that are hypothesized to have expanded from smaller refugia populations in the late Pleistocene. The method can accommodate data set heterogeneity such as variability in effective population size, mutation rates, and sample sizes across species and exploits the statistical strength from the simultaneous analysis of multiple species. This hABC framework used in a multitaxa demographic context can increase our understanding of the impact of historical climate change by determining what proportion of the community responded in concert or independently and can be used with a wide variety of comparative phylogeographic data sets as biota-wide DNA barcoding data sets accumulate. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Global aesthetic surgery statistics: a closer look.

PubMed

Heidekrueger, Paul I; Juran, S; Ehrl, D; Aung, T; Tanna, N; Broer, P Niclas

2017-08-01

Obtaining quality global statistics about surgical procedures remains an important yet challenging task. The International Society of Aesthetic Plastic Surgery (ISAPS) reports the total number of surgical and non-surgical procedures performed worldwide on a yearly basis. While providing valuable insight, ISAPS' statistics leave two important factors unaccounted for: (1) the underlying base population, and (2) the number of surgeons performing the procedures. Statistics of the published ISAPS' 'International Survey on Aesthetic/Cosmetic Surgery' were analysed by country, taking into account the underlying national base population according to the official United Nations population estimates. Further, the number of surgeons per country was used to calculate the number of surgeries performed per surgeon. In 2014, based on ISAPS statistics, national surgical procedures ranked in the following order: 1st USA, 2nd Brazil, 3rd South Korea, 4th Mexico, 5th Japan, 6th Germany, 7th Colombia, and 8th France. When considering the size of the underlying national populations, the demand for surgical procedures per 100,000 people changes the overall ranking substantially. It was also found that the rate of surgical procedures per surgeon shows great variation between the responding countries. While the US and Brazil are often quoted as the countries with the highest demand for plastic surgery, according to the presented analysis, other countries surpass these countries in surgical procedures per capita. While data acquisition and quality should be improved in the future, valuable insight regarding the demand for surgical procedures can be gained by taking specific demographic and geographic factors into consideration.

Measuring the statistical validity of summary meta-analysis and meta-regression results for use in clinical practice.

PubMed

Willis, Brian H; Riley, Richard D

2017-09-20

An important question for clinicians appraising a meta-analysis is: are the findings likely to be valid in their own practice-does the reported effect accurately represent the effect that would occur in their own clinical population? To this end we advance the concept of statistical validity-where the parameter being estimated equals the corresponding parameter for a new independent study. Using a simple ('leave-one-out') cross-validation technique, we demonstrate how we may test meta-analysis estimates for statistical validity using a new validation statistic, Vn, and derive its distribution. We compare this with the usual approach of investigating heterogeneity in meta-analyses and demonstrate the link between statistical validity and homogeneity. Using a simulation study, the properties of Vn and the Q statistic are compared for univariate random effects meta-analysis and a tailored meta-regression model, where information from the setting (included as model covariates) is used to calibrate the summary estimate to the setting of application. Their properties are found to be similar when there are 50 studies or more, but for fewer studies Vn has greater power but a higher type 1 error rate than Q. The power and type 1 error rate of Vn are also shown to depend on the within-study variance, between-study variance, study sample size, and the number of studies in the meta-analysis. Finally, we apply Vn to two published meta-analyses and conclude that it usefully augments standard methods when deciding upon the likely validity of summary meta-analysis estimates in clinical practice. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

GenAlEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research--an update.

PubMed

Peakall, Rod; Smouse, Peter E

2012-10-01

GenAlEx: Genetic Analysis in Excel is a cross-platform package for population genetic analyses that runs within Microsoft Excel. GenAlEx offers analysis of diploid codominant, haploid and binary genetic loci and DNA sequences. Both frequency-based (F-statistics, heterozygosity, HWE, population assignment, relatedness) and distance-based (AMOVA, PCoA, Mantel tests, multivariate spatial autocorrelation) analyses are provided. New features include calculation of new estimators of population structure: G'(ST), G''(ST), Jost's D(est) and F'(ST) through AMOVA, Shannon Information analysis, linkage disequilibrium analysis for biallelic data and novel heterogeneity tests for spatial autocorrelation analysis. Export to more than 30 other data formats is provided. Teaching tutorials and expanded step-by-step output options are included. The comprehensive guide has been fully revised. GenAlEx is written in VBA and provided as a Microsoft Excel Add-in (compatible with Excel 2003, 2007, 2010 on PC; Excel 2004, 2011 on Macintosh). GenAlEx, and supporting documentation and tutorials are freely available at: http://biology.anu.edu.au/GenAlEx. rod.peakall@anu.edu.au.

Intercomparison of textural parameters of intertidal sediments generated by different statistical procedures, and implications for a unifying descriptive nomenclature

NASA Astrophysics Data System (ADS)

Fan, Daidu; Tu, Junbiao; Cai, Guofu; Shang, Shuai

2015-06-01

Grain-size analysis is a basic routine in sedimentology and related fields, but diverse methods of sample collection, processing and statistical analysis often make direct comparisons and interpretations difficult or even impossible. In this paper, 586 published grain-size datasets from the Qiantang Estuary (East China Sea) sampled and analyzed by the same procedures were merged and their textural parameters calculated by a percentile and two moment methods. The aim was to explore which of the statistical procedures performed best in the discrimination of three distinct sedimentary units on the tidal flats of the middle Qiantang Estuary. A Gaussian curve-fitting method served to simulate mixtures of two normal populations having different modal sizes, sorting values and size distributions, enabling a better understanding of the impact of finer tail components on textural parameters, as well as the proposal of a unifying descriptive nomenclature. The results show that percentile and moment procedures yield almost identical results for mean grain size, and that sorting values are also highly correlated. However, more complex relationships exist between percentile and moment skewness (kurtosis), changing from positive to negative correlations when the proportions of the finer populations decrease below 35% (10%). This change results from the overweighting of tail components in moment statistics, which stands in sharp contrast to the underweighting or complete amputation of small tail components by the percentile procedure. Intercomparisons of bivariate plots suggest an advantage of the Friedman & Johnson moment procedure over the McManus moment method in terms of the description of grain-size distributions, and over the percentile method by virtue of a greater sensitivity to small variations in tail components. The textural parameter scalings of Folk & Ward were translated into their Friedman & Johnson moment counterparts by application of mathematical functions derived by regression analysis of measured and modeled grain-size data, or by determining the abscissa values of intersections between auxiliary lines running parallel to the x-axis and vertical lines corresponding to the descriptive percentile limits along the ordinate of representative bivariate plots. Twofold limits were extrapolated for the moment statistics in relation to single descriptive terms in the cases of skewness and kurtosis by considering both positive and negative correlations between percentile and moment statistics. The extrapolated descriptive scalings were further validated by examining entire size-frequency distributions simulated by mixing two normal populations of designated modal size and sorting values, but varying in mixing ratios. These were found to match well in most of the proposed scalings, although platykurtic and very platykurtic categories were questionable when the proportion of the finer population was below 5%. Irrespective of the statistical procedure, descriptive nomenclatures should therefore be cautiously used when tail components contribute less than 5% to grain-size distributions.

Statistical design and analysis plan for an impact evaluation of an HIV treatment and prevention intervention for female sex workers in Zimbabwe: a study protocol for a cluster randomised controlled trial.

PubMed

Hargreaves, James R; Fearon, Elizabeth; Davey, Calum; Phillips, Andrew; Cambiano, Valentina; Cowan, Frances M

2016-01-05

Pragmatic cluster-randomised trials should seek to make unbiased estimates of effect and be reported according to CONSORT principles, and the study population should be representative of the target population. This is challenging when conducting trials amongst 'hidden' populations without a sample frame. We describe a pair-matched cluster-randomised trial of a combination HIV-prevention intervention to reduce the proportion of female sex workers (FSW) with a detectable HIV viral load in Zimbabwe, recruiting via respondent driven sampling (RDS). We will cross-sectionally survey approximately 200 FSW at baseline and at endline to characterise each of 14 sites. RDS is a variant of chain referral sampling and has been adapted to approximate random sampling. Primary analysis will use the 'RDS-2' method to estimate cluster summaries and will adapt Hayes and Moulton's '2-step' method to adjust effect estimates for individual-level confounders and further adjust for cluster baseline prevalence. We will adapt CONSORT to accommodate RDS. In the absence of observable refusal rates, we will compare the recruitment process between matched pairs. We will need to investigate whether cluster-specific recruitment or the intervention itself affects the accuracy of the RDS estimation process, potentially causing differential biases. To do this, we will calculate RDS-diagnostic statistics for each cluster at each time point and compare these statistics within matched pairs and time points. Sensitivity analyses will assess the impact of potential biases arising from assumptions made by the RDS-2 estimation. We are not aware of any other completed pragmatic cluster RCTs that are recruiting participants using RDS. Our statistical design and analysis approach seeks to transparently document participant recruitment and allow an assessment of the representativeness of the study to the target population, a key aspect of pragmatic trials. The challenges we have faced in the design of this trial are likely to be shared in other contexts aiming to serve the needs of legally and/or socially marginalised populations for which no sampling frame exists and especially when the social networks of participants are both the target of intervention and the means of recruitment. The trial was registered at Pan African Clinical Trials Registry (PACTR201312000722390) on 9 December 2013.

Spatial analysis of electricity demand patterns in Greece: Application of a GIS-based methodological framework

NASA Astrophysics Data System (ADS)

Tyralis, Hristos; Mamassis, Nikos; Photis, Yorgos N.

2016-04-01

We investigate various uses of electricity demand in Greece (agricultural, commercial, domestic, industrial use as well as use for public and municipal authorities and street lightning) and we examine their relation with variables such as population, total area, population density and the Gross Domestic Product. The analysis is performed on data which span from 2008 to 2012 and have annual temporal resolution and spatial resolution down to the level of prefecture. We both visualize the results of the analysis and we perform cluster and outlier analysis using the Anselin local Moran's I statistic as well as hot spot analysis using the Getis-Ord Gi* statistic. The definition of the spatial patterns and relationships of the aforementioned variables in a GIS environment provides meaningful insight and better understanding of the regional development model in Greece and justifies the basis for an energy demand forecasting methodology. Acknowledgement: This research has been partly financed by the European Union (European Social Fund - ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: ARISTEIA II: Reinforcement of the interdisciplinary and/ or inter-institutional research and innovation (CRESSENDO project; grant number 5145).

Andreev Bound States Formation and Quasiparticle Trapping in Quench Dynamics Revealed by Time-Dependent Counting Statistics.

PubMed

Souto, R Seoane; Martín-Rodero, A; Yeyati, A Levy

2016-12-23

We analyze the quantum quench dynamics in the formation of a phase-biased superconducting nanojunction. We find that in the absence of an external relaxation mechanism and for very general conditions the system gets trapped in a metastable state, corresponding to a nonequilibrium population of the Andreev bound states. The use of the time-dependent full counting statistics analysis allows us to extract information on the asymptotic population of even and odd many-body states, demonstrating that a universal behavior, dependent only on the Andreev state energy, is reached in the quantum point contact limit. These results shed light on recent experimental observations on quasiparticle trapping in superconducting atomic contacts.

Impact of some types of mass gatherings on current suicide risk in an urban population: statistical and negative binominal regression analysis of time series.

PubMed

Usenko, Vasiliy S; Svirin, Sergey N; Shchekaturov, Yan N; Ponarin, Eduard D

2014-04-04

Many studies have investigated the impact of a wide range of social events on suicide-related behaviour. However, these studies have predominantly examined national events. The aim of this study is to provide a statistical evaluation of the relationship between mass gatherings in some relatively small urban sub-populations and the general suicide rates of a major city. The data were gathered in the Ukrainian city of Dnipropetrovsk, with a population of 1 million people, in 2005-2010. Suicide attempts, suicides, and the total amount of suicide-related behaviours were registered daily for each sex. Bivariate and multivariate statistical analysis, including negative binomial regression, were applied to assess the risk of suicide-related behaviour in the city's general population for 7 days before and after 427 mass gatherings, such as concerts, football games, and non-regular mass events organized by the Orthodox Church and new religious movements. The bivariate and multivariate statistical analyses found significant changes in some suicide-related behaviour rates in the city's population after certain kinds of mass gatherings. In particular, we observed an increased relative risk (RR) of male suicide-related behaviour after a home defeat of the local football team (RR = 1.32, p = 0.047; regression coefficient beta = 0.371, p = 0.002), and an increased risk of male suicides (RR = 1.29, p = 0.006; beta =0.255, p = 0.002), male suicide-related behaviour (RR = 1.25, p = 0.019; beta =0.251, p < 0.001), and total suicide-related behaviour (RR = 1.23 p < 0.001; beta =0.187, p < 0.001) after events organized by the new religious movements. Although football games and mass events organized by new religious movements involved a relatively small part of an urban population (1.6 and 0.3%, respectively), we observed a significant increase of the some suicide-related behaviour rates in the whole population. It is likely that the observed effect on suicide-related behaviour is related to one's personal presence at the event rather than to its broadcast. Our findings can be explained largely in terms of Gabennesch's theory of the 'broken-promises effect' with regard to intra- and interpersonal conflict and, in terms of crowd behaviour effects.

Cure model survival analysis after hepatic resection for colorectal liver metastases.

PubMed

Cucchetti, Alessando; Ferrero, Alessandro; Cescon, Matteo; Donadon, Matteo; Russolillo, Nadia; Ercolani, Giorgio; Stacchini, Giacomo; Mazzotti, Federico; Torzilli, Guido; Pinna, Antonio Daniele

2015-01-01

Statistical cure is achieved when a patient population has the same mortality as cancer-free individuals; however, data regarding the probability of cure after hepatectomy of colorectal liver metastases (CLM) have never been provided. We aimed to assess the probability of being statistically cured from CLM by hepatic resection. Data from 1,012 consecutive patients undergoing curative resection for CLM (2001-2012) were used to fit a nonmixture cure model to compare mortality after surgery to that expected for the general population matched by sex and age. The 5- and 10-year disease-free survival was 18.9 and 15.8 %; the corresponding overall survival was 44.3 and 32.7 %. In the entire study population, the probability of being cured from CLM was 20 % (95 % confidence interval 16.5-23.5). After the first year, the mortality excess of resected patients, in comparison to the general population, starts to decline until it approaches zero 6 years after surgery. After 6.48 years, patients alive without tumor recurrence can be considered cured with 99 % certainty. Multivariate analysis showed that cure probabilities range from 40.9 % in patients with node-negative primary tumors and metachronous presentation of a single lesion <3 cm, to 1.5 % in patients with node positivity, and synchronous presentation of multiple, large CLMs. A model for the calculation of a cure fraction for each possible clinical scenario is provided. Using a cure model, the present results indicate that statistical cure of CLM is possible after hepatectomy; providing this information can help clinicians give more precise answer to patients' questions.

[Respondent-Driven Sampling: a new sampling method to study visible and hidden populations].

PubMed

Mantecón, Alejandro; Juan, Montse; Calafat, Amador; Becoña, Elisardo; Román, Encarna

2008-01-01

The paper introduces a variant of chain-referral sampling: respondent-driven sampling (RDS). This sampling method shows that methods based on network analysis can be combined with the statistical validity of standard probability sampling methods. In this sense, RDS appears to be a mathematical improvement of snowball sampling oriented to the study of hidden populations. However, we try to prove its validity with populations that are not within a sampling frame but can nonetheless be contacted without difficulty. The basics of RDS are explained through our research on young people (aged 14 to 25) who go clubbing, consume alcohol and other drugs, and have sex. Fieldwork was carried out between May and July 2007 in three Spanish regions: Baleares, Galicia and Comunidad Valenciana. The presentation of the study shows the utility of this type of sampling when the population is accessible but there is a difficulty deriving from the lack of a sampling frame. However, the sample obtained is not a random representative one in statistical terms of the target population. It must be acknowledged that the final sample is representative of a 'pseudo-population' that approximates to the target population but is not identical to it.

Automated finite element modeling of the lumbar spine: Using a statistical shape model to generate a virtual population of models.

PubMed

Campbell, J Q; Petrella, A J

2016-09-06

Population-based modeling of the lumbar spine has the potential to be a powerful clinical tool. However, developing a fully parameterized model of the lumbar spine with accurate geometry has remained a challenge. The current study used automated methods for landmark identification to create a statistical shape model of the lumbar spine. The shape model was evaluated using compactness, generalization ability, and specificity. The primary shape modes were analyzed visually, quantitatively, and biomechanically. The biomechanical analysis was performed by using the statistical shape model with an automated method for finite element model generation to create a fully parameterized finite element model of the lumbar spine. Functional finite element models of the mean shape and the extreme shapes (±3 standard deviations) of all 17 shape modes were created demonstrating the robust nature of the methods. This study represents an advancement in finite element modeling of the lumbar spine and will allow population-based modeling in the future. Copyright © 2016 Elsevier Ltd. All rights reserved.

7 CFR 2.17 - Under Secretary for Rural Development.

Code of Federal Regulations, 2012 CFR

2012-01-01

... economic, social, and environmental research and analysis, statistical programs, and associated service...; rural population and manpower; local government finance; income development strategies; housing; social... activities. (12) Assist other Federal agencies in formulating manpower development and training policies. (13...

7 CFR 2.17 - Under Secretary for Rural Development.

Code of Federal Regulations, 2011 CFR

2011-01-01

... economic, social, and environmental research and analysis, statistical programs, and associated service...; rural population and manpower; local government finance; income development strategies; housing; social... activities. (12) Assist other Federal agencies in formulating manpower development and training policies. (13...

Population trends of North American shorebirds based on the International Shorebird Survey

USGS Publications Warehouse

Howe, M.A.; Geissler, P.H.; Harrington, B.A.

1989-01-01

Shorebirds (Charadiiformes) are prime candidates for population decline because of their dependence on wetlands that are being lost at a rapid pace. Thirty-six of the 49 species of shorebirds that breed in North America spend most of the year in Latin America. Because populations of most species breed and winter at remote sites , it may be feasible to monitor their numbers at migration stopovers. In this study, we used statistical trend analysis methods, developed for the North American Breeding Bird Survey, to analyze data on shorebird populations during south-bound migration in the United States. Survey data were collected by volunteers in the International Shorebird Survey (ISS). Methodological concerns over both the ISS and the trend analysis procedures are discussed in detail and biological interpretations of the results are suggested.

Assessing human metal accumulations in an urban superfund site.

PubMed

Hailer, M Katie; Peck, Christopher P; Calhoun, Michael W; West, Robert F; James, Kyle J; Siciliano, Steven D

2017-09-01

Butte, Montana is part of the largest superfund site in the continental United States. Open-pit mining continues in close proximity to Butte's urban population. This study seeks to establish baseline metal concentrations in the hair and blood of individuals living in Butte, MT and possible routes of exposure. Volunteers from Butte (n=116) and Bozeman (n=86) were recruited to submit hair and blood samples and asked to complete a lifestyle survey. Elemental analysis of hair and blood samples was performed by ICP-MS. Three air monitors were stationed in Butte to collect particulate and filters were analyzed by ICP-MS. Soil samples from the yards of Butte volunteers were quantified by ICP-MS. Hair analysis revealed concentrations of Al, As, Cd, Cu, Mn, Mo, and U to be statistically elevated in Butte's population. Blood analysis revealed that the concentration of As was also statistically elevated in the Butte population. Multiple regression analysis was performed for the elements As, Cu, and Mn for hair and blood samples. Soil samples revealed detectable levels of As, Pb, Cu, Mn, and Cd, with As and Cu levels being higher than expected in some of the samples. Air sampling revealed consistently elevated As and Mn levels in the larger particulate sampled as compared to average U.S. ambient air data. Copyright © 2017 Elsevier B.V. All rights reserved.

A Class of Population Covariance Matrices in the Bootstrap Approach to Covariance Structure Analysis

ERIC Educational Resources Information Center

Yuan, Ke-Hai; Hayashi, Kentaro; Yanagihara, Hirokazu

2007-01-01

Model evaluation in covariance structure analysis is critical before the results can be trusted. Due to finite sample sizes and unknown distributions of real data, existing conclusions regarding a particular statistic may not be applicable in practice. The bootstrap procedure automatically takes care of the unknown distribution and, for a given…

Hierarchical models and bayesian analysis of bird survey information

Treesearch

John R. Sauer; William A. Link; J. Andrew Royle

2005-01-01

Summary of bird survey information is a critical component of conservation activities, but often our summaries rely on statistical methods that do not accommodate the limitations of the information. Prioritization of species requires ranking and analysis of species by magnitude of population trend, but often magnitude of trend is a misleading measure of actual decline...

Number of Black Children in Extreme Poverty Hits Record High. Analysis Background.

ERIC Educational Resources Information Center

Children's Defense Fund, Washington, DC.

To examine the experiences of black children and poverty, researchers conducted a computer analysis of data from the U.S. Census Bureau's Current Population Survey, the source of official government poverty statistics. The data are through 2001. Results indicated that nearly 1 million black children were living in extreme poverty, with after-tax…

Not the Norm: The Potential of Tree Analysis of Performance Data from Students in a Foundation Mathematics Module

ERIC Educational Resources Information Center

Kirby, Nicola; Dempster, Edith

2015-01-01

Quantitative methods of data analysis usually involve inferential statistics, and are not well known for their ability to reflect the intricacies of a diverse student population. The South African tertiary education sector is characterised by extreme inequality and diversity. Foundation programmes address issues of inequality of access by…

Using Multi-Group Confirmatory Factor Analysis to Evaluate Cross-Cultural Research: Identifying and Understanding Non-Invariance

ERIC Educational Resources Information Center

Brown, Gavin T. L.; Harris, Lois R.; O'Quin, Chrissie; Lane, Kenneth E.

2017-01-01

Multi-group confirmatory factor analysis (MGCFA) allows researchers to determine whether a research inventory elicits similar response patterns across samples. If statistical equivalence in responding is found, then scale score comparisons become possible and samples can be said to be from the same population. This paper illustrates the use of…

Resilience Scale-25 Spanish version: validation and assessment in eating disorders.

PubMed

Las Hayas, Carlota; Calvete, Esther; Gómez del Barrio, Andrés; Beato, Luís; Muñoz, Pedro; Padierna, Jesús Ángel

2014-08-01

To validate into Spanish the Wagnild and Young Resilience Scale - 25 (RS-25), assess and compare the scores on the scale among women from the general population, eating disorder (ED) patients and recovered ED patients. This is a cross-sectional study. ED participants were invited to participate by their respective therapists. The sample from the general population was gathered via an open online survey. Participants (N general population=279; N ED patients=124; and N recovered ED patients=45) completed the RS-25, the World Health Organization Quality of Life Scale-BREF and the Hospital Anxiety and Depression Scale. Mean age of participants ranged from 28.87 to 30.42years old. Statistical analysis included a multi-group confirmatory factor analysis and ANOVA. The two-factor model of the RS-25 produced excellent fit indexes. Measurement invariance across samples was generally supported. The ANOVA found statistically significant differences in the RS-25 mean scores between the ED patients (Mean=103.13, SD=31.32) and the recovered ED participants (Mean=138.42, SD=22.26) and between the ED patients and the general population participants (Mean=136.63, SD=19.56). The Spanish version of the RS-25 is a psychometrically sound measurement tool in samples of ED patients. Resilience is lower in people diagnosed with ED than in recovered individuals and the general population. Copyright © 2014 Elsevier Ltd. All rights reserved.

Challenges of Big Data Analysis.

PubMed

Fan, Jianqing; Han, Fang; Liu, Han

2014-06-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions.

Challenges of Big Data Analysis

PubMed Central

Fan, Jianqing; Han, Fang; Liu, Han

2014-01-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions. PMID:25419469

A Statistical Assessment of Information, Knowledge and Attitudes of Medical Students Regarding Contraception Use.

PubMed

Simionescu, Anca A; Horobet, Alexandra; Belascu, Lucian

2017-12-01

To evaluate how contraception use is linked to information, knowledge and attitudes towards family planning and contraception of medical students. This is a voluntary cross-sectional study using an anonymous questionnaire applied to 62 medical students. The questionnaire had the following main structure: characteristics of the studied population, information on contraception, knowledge about contraception methods, attitudes regarding family planning and contraception, and contraception use. Statistical analysis was performed using STATISTICA 8.0 software and statistical significance of the data was verified using the t-statistic test. The survey had a 95% response rate. Seventy seven percent of the studied population consisted of females aged between 20-40 years, with 85.50% of them being 20-25 years old. The overwhelming majority of respondents believed it was important to be informed on the subject and considered themselves to be well informed on contraception. The internet and courses are the main sources of information. Of all respondents, 75.41% had routine discussions with their partners regarding contraception, 53.23% talked about it with family members and 46.77% with their physician; 90.16% had at least one gynecological examination and 47.54% got themselves tested for sexually transmitted diseases. The condom and the contraceptive pill were the main contraceptive methods for the respondents. Romanian medical students share similar features to their peers in European developed countries. We used a statistical analysis to demonstrate that information, knowledge and attitudes on contraception are closely linked to contraceptive choice.

Evaluation of redundancy analysis to identify signatures of local adaptation.

PubMed

Capblancq, Thibaut; Luu, Keurcien; Blum, Michael G B; Bazin, Eric

2018-05-26

Ordination is a common tool in ecology that aims at representing complex biological information in a reduced space. In landscape genetics, ordination methods such as principal component analysis (PCA) have been used to detect adaptive variation based on genomic data. Taking advantage of environmental data in addition to genotype data, redundancy analysis (RDA) is another ordination approach that is useful to detect adaptive variation. This paper aims at proposing a test statistic based on RDA to search for loci under selection. We compare redundancy analysis to pcadapt, which is a nonconstrained ordination method, and to a latent factor mixed model (LFMM), which is a univariate genotype-environment association method. Individual-based simulations identify evolutionary scenarios where RDA genome scans have a greater statistical power than genome scans based on PCA. By constraining the analysis with environmental variables, RDA performs better than PCA in identifying adaptive variation when selection gradients are weakly correlated with population structure. Additionally, we show that if RDA and LFMM have a similar power to identify genetic markers associated with environmental variables, the RDA-based procedure has the advantage to identify the main selective gradients as a combination of environmental variables. To give a concrete illustration of RDA in population genomics, we apply this method to the detection of outliers and selective gradients on an SNP data set of Populus trichocarpa (Geraldes et al., 2013). The RDA-based approach identifies the main selective gradient contrasting southern and coastal populations to northern and continental populations in the northwestern American coast. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Human population growth and temperature increase along with the increase in urbanisation, motor vehicle numbers and green area amount in the sample of Erzurum city, Turkey.

PubMed

Yilmaz, Sevgi; Toy, Süleyman; Demircioglu Yildiz, Nalan; Yilmaz, Hasan

2009-01-01

In the study, main purpose was to determine the effect of population growth along with the increase in urbanisation, motor vehicle use and green area amount on the temperature values using a 55-year data set in Erzurum, which is hardly industrialised, and one of the coldest cities with highest elevation in Turkey. Although the semi-decadal increases, means of which are 0.1 degrees C for mean, minimum and maximum temperatures, are not clear enough to make a strong comment even in the lights of figures or tables, it was found as the result of the statistical analysis that population growth and increases in the number of vehicles, the number of buildings and the green area amount in the city have no significant effect on mean temperatures. However, the relationships between population growth and maximum temperature; and the number of vehicles and minimum temperature were found to be statistically significant.

Modeling of LEO Orbital Debris Populations in Centimeter and Millimeter Size Regimes

NASA Technical Reports Server (NTRS)

Xu, Y.-L.; Hill, . M.; Horstman, M.; Krisko, P. H.; Liou, J.-C.; Matney, M.; Stansbery, E. G.

2010-01-01

The building of the NASA Orbital Debris Engineering Model, whether ORDEM2000 or its recently updated version ORDEM2010, uses as its foundation a number of model debris populations, each truncated at a minimum object-size ranging from 10 micron to 1 m. This paper discusses the development of the ORDEM2010 model debris populations in LEO (low Earth orbit), focusing on centimeter (smaller than 10 cm) and millimeter size regimes. Primary data sets used in the statistical derivation of the cm- and mm-size model populations are from the Haystack radar operated in a staring mode. Unlike cataloged objects of sizes greater than approximately 10 cm, ground-based radars monitor smaller-size debris only in a statistical manner instead of tracking every piece. The mono-static Haystack radar can detect debris as small as approximately 5 mm at moderate LEO altitudes. Estimation of millimeter debris populations (for objects smaller than approximately 6 mm) rests largely on Goldstone radar measurements. The bi-static Goldstone radar can detect 2- to 3-mm objects. The modeling of the cm- and mm-debris populations follows the general approach to developing other ORDEM2010-required model populations for various components and types of debris. It relies on appropriate reference populations to provide necessary prior information on the orbital structures and other important characteristics of the debris objects. NASA's LEO-to-GEO Environment Debris (LEGEND) model is capable of furnishing such reference populations in the desired size range. A Bayesian statistical inference process, commonly adopted in ORDEM2010 model-population derivations, changes a priori distribution into a posteriori distribution and thus refines the reference populations in terms of data. This paper describes key elements and major steps in the statistical derivations of the cm- and mm-size debris populations and presents results. Due to lack of data for near 1-mm sizes, the model populations of 1- to 3.16-mm objects are an empirical extension from larger debris. The extension takes into account the results of micro-debris (from 10 micron to 1 mm) population modeling that is based on shuttle impact data, in the hope of making a smooth transition between micron and millimeter size regimes. This paper also includes a brief discussion on issues and potential future work concerning the analysis and interpretation of Goldstone radar data.

Dynamics and regulation of the southern brook trout (Salvelinus fontinalis) population in an Appalachian stream

Treesearch

Gary D. Grossman; Robert E. Ratajczak; C. Michael Wagner; J. Todd Petty

2010-01-01

1. We used information theoretic statistics [Akaike’s Information Criterion (AIC)] and regression analysis in a multiple hypothesis testing approach to assess the processes capable of explaining long-term demographic variation in a lightly exploited brook trout population in Ball Creek, NC. We sampled a 100-m-long second-order site during both spring and autumn 1991–...

Money Income and Poverty Status of Families and Persons in the United States: 1985. (Advance Data from the March 1986 Current Population Survey).

ERIC Educational Resources Information Center

Current Population Reports, 1986

1986-01-01

Analysis of information gained from the March 1986 Current Population Survey (CPS) conducted by the Bureau of the Census shows the following results for the year 1985: (1) median family money income continued to move ahead of inflation; (2) the median earnings of men showed no statistically significant change from 1984, but the earnings of women…

Population Genomics and the Statistical Values of Race: An Interdisciplinary Perspective on the Biological Classification of Human Populations and Implications for Clinical Genetic Epidemiological Research

PubMed Central

Maglo, Koffi N.; Mersha, Tesfaye B.; Martin, Lisa J.

2016-01-01

The biological status and biomedical significance of the concept of race as applied to humans continue to be contentious issues despite the use of advanced statistical and clustering methods to determine continental ancestry. It is thus imperative for researchers to understand the limitations as well as potential uses of the concept of race in biology and biomedicine. This paper deals with the theoretical assumptions behind cluster analysis in human population genomics. Adopting an interdisciplinary approach, it demonstrates that the hypothesis that attributes the clustering of human populations to “frictional” effects of landform barriers at continental boundaries is empirically incoherent. It then contrasts the scientific status of the “cluster” and “cline” constructs in human population genomics, and shows how cluster may be instrumentally produced. It also shows how statistical values of race vindicate Darwin's argument that race is evolutionarily meaningless. Finally, the paper explains why, due to spatiotemporal parameters, evolutionary forces, and socio-cultural factors influencing population structure, continental ancestry may be pragmatically relevant to global and public health genomics. Overall, this work demonstrates that, from a biological systematic and evolutionary taxonomical perspective, human races/continental groups or clusters have no natural meaning or objective biological reality. In fact, the utility of racial categorizations in research and in clinics can be explained by spatiotemporal parameters, socio-cultural factors, and evolutionary forces affecting disease causation and treatment response. PMID:26925096

Population changes in residential clusters in Japan.

PubMed

Sekiguchi, Takuya; Tamura, Kohei; Masuda, Naoki

2018-01-01

Population dynamics in urban and rural areas are different. Understanding factors that contribute to local population changes has various socioeconomic and political implications. In the present study, we use population census data in Japan to examine contributors to the population growth of residential clusters between years 2005 and 2010. The data set covers the entirety of Japan and has a high spatial resolution of 500 × 500 m2, enabling us to examine population dynamics in various parts of the country (urban and rural) using statistical analysis. We found that, in addition to the area, population density, and age, the shape of the cluster and the spatial distribution of inhabitants within the cluster are significantly related to the population growth rate of a residential cluster. Specifically, the population tends to grow if the cluster is "round" shaped (given the area) and the population is concentrated near the center rather than periphery of the cluster. Combination of the present results and analysis framework with other factors that have been omitted in the present study, such as migration, terrain, and transportation infrastructure, will be fruitful.

Spatial genetic structure of the cyprinid fish Onychostoma lepturum on Hainan Island.

PubMed

Zhou, Tian-Qi; Lin, Hung-Du; Hsu, Kui-Ching; Kuo, Po-Hsun; Wang, Wei-Kuang; Tang, Wen-Qiao; Liu, Dong; Yang, Jin-Quan

2017-11-01

Population genetic structure of Onychostoma lepturum on Hainan Island was investigated based on mitochondrial CR + cyt b region in 63 specimens collected from four populations. Population analyses indicated significant genetic structure (F ST  = 0.749) and displayed a significant relationship between phylogeny and geography (N ST  = 0.750 and G ST  = 0.140). Thirty-one mtDNA haplotypes were classified into four lineages, and these lineages had an almost allopatric distribution. The results of a statistical dispersal-vicariance analysis suggest that the ancestral populations were distributed widely on Hainan Island, and the rising of the central mountainous area of Hainan Island, the Wuzhi and Yinggeling Mountain Range, separated these four drainages into independent lineages. According to a spatial analysis of molecular variance analysis, we divided these populations into three units: ND, CH and WQ + LS, running into Qiongzhou Strait, the Gulf of Tokin and the South China Sea, respectively. According to our study, the exposure of straits and shelf under water retreat gave chances for population dispersion during the glaciations.

Classification accuracy on the family planning participation status using kernel discriminant analysis

NASA Astrophysics Data System (ADS)

Kurniawan, Dian; Suparti; Sugito

2018-05-01

Population growth in Indonesia has increased every year. According to the population census conducted by the Central Bureau of Statistics (BPS) in 2010, the population of Indonesia has reached 237.6 million people. Therefore, to control the population growth rate, the government hold Family Planning or Keluarga Berencana (KB) program for couples of childbearing age. The purpose of this program is to improve the health of mothers and children in order to manifest prosperous society by controlling births while ensuring control of population growth. The data used in this study is the updated family data of Semarang city in 2016 that conducted by National Family Planning Coordinating Board (BKKBN). From these data, classifiers with kernel discriminant analysis will be obtained, and also classification accuracy will be obtained from that method. The result of the analysis showed that normal kernel discriminant analysis gives 71.05 % classification accuracy with 28.95 % classification error. Whereas triweight kernel discriminant analysis gives 73.68 % classification accuracy with 26.32 % classification error. Using triweight kernel discriminant for data preprocessing of family planning participation of childbearing age couples in Semarang City of 2016 can be stated better than with normal kernel discriminant.

A Genome-Wide Association Analysis Reveals Epistatic Cancellation of Additive Genetic Variance for Root Length in Arabidopsis thaliana.

PubMed

Lachowiec, Jennifer; Shen, Xia; Queitsch, Christine; Carlborg, Örjan

2015-01-01

Efforts to identify loci underlying complex traits generally assume that most genetic variance is additive. Here, we examined the genetics of Arabidopsis thaliana root length and found that the genomic narrow-sense heritability for this trait in the examined population was statistically zero. The low amount of additive genetic variance that could be captured by the genome-wide genotypes likely explains why no associations to root length could be found using standard additive-model-based genome-wide association (GWA) approaches. However, as the broad-sense heritability for root length was significantly larger, and primarily due to epistasis, we also performed an epistatic GWA analysis to map loci contributing to the epistatic genetic variance. Four interacting pairs of loci were revealed, involving seven chromosomal loci that passed a standard multiple-testing corrected significance threshold. The genotype-phenotype maps for these pairs revealed epistasis that cancelled out the additive genetic variance, explaining why these loci were not detected in the additive GWA analysis. Small population sizes, such as in our experiment, increase the risk of identifying false epistatic interactions due to testing for associations with very large numbers of multi-marker genotypes in few phenotyped individuals. Therefore, we estimated the false-positive risk using a new statistical approach that suggested half of the associated pairs to be true positive associations. Our experimental evaluation of candidate genes within the seven associated loci suggests that this estimate is conservative; we identified functional candidate genes that affected root development in four loci that were part of three of the pairs. The statistical epistatic analyses were thus indispensable for confirming known, and identifying new, candidate genes for root length in this population of wild-collected A. thaliana accessions. We also illustrate how epistatic cancellation of the additive genetic variance explains the insignificant narrow-sense and significant broad-sense heritability by using a combination of careful statistical epistatic analyses and functional genetic experiments.

Accounting for Population Structure in Gene-by-Environment Interactions in Genome-Wide Association Studies Using Mixed Models.

PubMed

Sul, Jae Hoon; Bilow, Michael; Yang, Wen-Yun; Kostem, Emrah; Furlotte, Nick; He, Dan; Eskin, Eleazar

2016-03-01

Although genome-wide association studies (GWASs) have discovered numerous novel genetic variants associated with many complex traits and diseases, those genetic variants typically explain only a small fraction of phenotypic variance. Factors that account for phenotypic variance include environmental factors and gene-by-environment interactions (GEIs). Recently, several studies have conducted genome-wide gene-by-environment association analyses and demonstrated important roles of GEIs in complex traits. One of the main challenges in these association studies is to control effects of population structure that may cause spurious associations. Many studies have analyzed how population structure influences statistics of genetic variants and developed several statistical approaches to correct for population structure. However, the impact of population structure on GEI statistics in GWASs has not been extensively studied and nor have there been methods designed to correct for population structure on GEI statistics. In this paper, we show both analytically and empirically that population structure may cause spurious GEIs and use both simulation and two GWAS datasets to support our finding. We propose a statistical approach based on mixed models to account for population structure on GEI statistics. We find that our approach effectively controls population structure on statistics for GEIs as well as for genetic variants.

Rare-Variant Association Analysis: Study Designs and Statistical Tests

PubMed Central

Lee, Seunggeung; Abecasis, Gonçalo R.; Boehnke, Michael; Lin, Xihong

2014-01-01

Despite the extensive discovery of trait- and disease-associated common variants, much of the genetic contribution to complex traits remains unexplained. Rare variants can explain additional disease risk or trait variability. An increasing number of studies are underway to identify trait- and disease-associated rare variants. In this review, we provide an overview of statistical issues in rare-variant association studies with a focus on study designs and statistical tests. We present the design and analysis pipeline of rare-variant studies and review cost-effective sequencing designs and genotyping platforms. We compare various gene- or region-based association tests, including burden tests, variance-component tests, and combined omnibus tests, in terms of their assumptions and performance. Also discussed are the related topics of meta-analysis, population-stratification adjustment, genotype imputation, follow-up studies, and heritability due to rare variants. We provide guidelines for analysis and discuss some of the challenges inherent in these studies and future research directions. PMID:24995866

Determination of reference ranges for elements in human scalp hair.

PubMed

Druyan, M E; Bass, D; Puchyr, R; Urek, K; Quig, D; Harmon, E; Marquardt, W

1998-06-01

Expected values, reference ranges, or reference limits are necessary to enable clinicians to apply analytical chemical data in the delivery of health care. Determination of references ranges is not straightforward in terms of either selecting a reference population or performing statistical analysis. In light of logistical, scientific, and economic obstacles, it is understandable that clinical laboratories often combine approaches in developing health associated reference values. A laboratory may choose to: 1. Validate either reference ranges of other laboratories or published data from clinical research or both, through comparison of patients test data. 2. Base the laboratory's reference values on statistical analysis of results from specimens assayed by the clinical reference laboratory itself. 3. Adopt standards or recommendations of regulatory agencies and governmental bodies. 4. Initiate population studies to validate transferred reference ranges or to determine them anew. Effects of external contamination and anecdotal information from clinicians may be considered. The clinical utility of hair analysis is well accepted for some elements. For others, it remains in the realm of clinical investigation. This article elucidates an approach for establishment of reference ranges for elements in human scalp hair. Observed levels of analytes from hair specimens from both our laboratory's total patient population and from a physician-defined healthy American population have been evaluated. Examination of levels of elements often associated with toxicity serves to exemplify the process of determining reference ranges in hair. In addition the approach serves as a model for setting reference ranges for analytes in a variety of matrices.

Twenty-five years of maximum-entropy principle

NASA Astrophysics Data System (ADS)

Kapur, J. N.

1983-04-01

The strengths and weaknesses of the maximum entropy principle (MEP) are examined and some challenging problems that remain outstanding at the end of the first quarter century of the principle are discussed. The original formalism of the MEP is presented and its relationship to statistical mechanics is set forth. The use of MEP for characterizing statistical distributions, in statistical inference, nonlinear spectral analysis, transportation models, population density models, models for brand-switching in marketing and vote-switching in elections is discussed. Its application to finance, insurance, image reconstruction, pattern recognition, operations research and engineering, biology and medicine, and nonparametric density estimation is considered.

Toxicity of zero-valent iron nanoparticles to a trichloroethylene-degrading groundwater microbial community.

PubMed

Zabetakis, Kara M; Niño de Guzmán, Gabriela T; Torrents, Alba; Yarwood, Stephanie

2015-01-01

The microbiological impact of zero-valent iron used in the remediation of groundwater was investigated by exposing a trichloroethylene-degrading anaerobic microbial community to two types of iron nanoparticles. Changes in total bacterial and archaeal population numbers were analyzed using qPCR and were compared to results from a blank and negative control to assess for microbial toxicity. Additionally, the results were compared to those of samples exposed to silver nanoparticles and iron filings in an attempt to discern the source of toxicity. Statistical analysis revealed that the three different iron treatments were equally toxic to the total bacteria and archaea populations, as compared with the controls. Conversely, the silver nanoparticles had a limited statistical impact when compared to the controls and increased the microbial populations in some instances. Therefore, the findings suggest that zero-valent iron toxicity does not result from a unique nanoparticle-based effect.

Finding differentially expressed genes in high dimensional data: Rank based test statistic via a distance measure.

PubMed

Mathur, Sunil; Sadana, Ajit

2015-12-01

We present a rank-based test statistic for the identification of differentially expressed genes using a distance measure. The proposed test statistic is highly robust against extreme values and does not assume the distribution of parent population. Simulation studies show that the proposed test is more powerful than some of the commonly used methods, such as paired t-test, Wilcoxon signed rank test, and significance analysis of microarray (SAM) under certain non-normal distributions. The asymptotic distribution of the test statistic, and the p-value function are discussed. The application of proposed method is shown using a real-life data set. © The Author(s) 2011.

Measuring the statistical validity of summary meta‐analysis and meta‐regression results for use in clinical practice

PubMed Central

Riley, Richard D.

2017-01-01

An important question for clinicians appraising a meta‐analysis is: are the findings likely to be valid in their own practice—does the reported effect accurately represent the effect that would occur in their own clinical population? To this end we advance the concept of statistical validity—where the parameter being estimated equals the corresponding parameter for a new independent study. Using a simple (‘leave‐one‐out’) cross‐validation technique, we demonstrate how we may test meta‐analysis estimates for statistical validity using a new validation statistic, Vn, and derive its distribution. We compare this with the usual approach of investigating heterogeneity in meta‐analyses and demonstrate the link between statistical validity and homogeneity. Using a simulation study, the properties of Vn and the Q statistic are compared for univariate random effects meta‐analysis and a tailored meta‐regression model, where information from the setting (included as model covariates) is used to calibrate the summary estimate to the setting of application. Their properties are found to be similar when there are 50 studies or more, but for fewer studies Vn has greater power but a higher type 1 error rate than Q. The power and type 1 error rate of Vn are also shown to depend on the within‐study variance, between‐study variance, study sample size, and the number of studies in the meta‐analysis. Finally, we apply Vn to two published meta‐analyses and conclude that it usefully augments standard methods when deciding upon the likely validity of summary meta‐analysis estimates in clinical practice. © 2017 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd. PMID:28620945

Functional genomics annotation of a statistical epistasis network associated with bladder cancer susceptibility.

PubMed

Hu, Ting; Pan, Qinxin; Andrew, Angeline S; Langer, Jillian M; Cole, Michael D; Tomlinson, Craig R; Karagas, Margaret R; Moore, Jason H

2014-04-11

Several different genetic and environmental factors have been identified as independent risk factors for bladder cancer in population-based studies. Recent studies have turned to understanding the role of gene-gene and gene-environment interactions in determining risk. We previously developed the bioinformatics framework of statistical epistasis networks (SEN) to characterize the global structure of interacting genetic factors associated with a particular disease or clinical outcome. By applying SEN to a population-based study of bladder cancer among Caucasians in New Hampshire, we were able to identify a set of connected genetic factors with strong and significant interaction effects on bladder cancer susceptibility. To support our statistical findings using networks, in the present study, we performed pathway enrichment analyses on the set of genes identified using SEN, and found that they are associated with the carcinogen benzo[a]pyrene, a component of tobacco smoke. We further carried out an mRNA expression microarray experiment to validate statistical genetic interactions, and to determine if the set of genes identified in the SEN were differentially expressed in a normal bladder cell line and a bladder cancer cell line in the presence or absence of benzo[a]pyrene. Significant nonrandom sets of genes from the SEN were found to be differentially expressed in response to benzo[a]pyrene in both the normal bladder cells and the bladder cancer cells. In addition, the patterns of gene expression were significantly different between these two cell types. The enrichment analyses and the gene expression microarray results support the idea that SEN analysis of bladder in population-based studies is able to identify biologically meaningful statistical patterns. These results bring us a step closer to a systems genetic approach to understanding cancer susceptibility that integrates population and laboratory-based studies.

Properties of different selection signature statistics and a new strategy for combining them.

PubMed

Ma, Y; Ding, X; Qanbari, S; Weigend, S; Zhang, Q; Simianer, H

2015-11-01

Identifying signatures of recent or ongoing selection is of high relevance in livestock population genomics. From a statistical perspective, determining a proper testing procedure and combining various test statistics is challenging. On the basis of extensive simulations in this study, we discuss the statistical properties of eight different established selection signature statistics. In the considered scenario, we show that a reasonable power to detect selection signatures is achieved with high marker density (>1 SNP/kb) as obtained from sequencing, while rather small sample sizes (~15 diploid individuals) appear to be sufficient. Most selection signature statistics such as composite likelihood ratio and cross population extended haplotype homozogysity have the highest power when fixation of the selected allele is reached, while integrated haplotype score has the highest power when selection is ongoing. We suggest a novel strategy, called de-correlated composite of multiple signals (DCMS) to combine different statistics for detecting selection signatures while accounting for the correlation between the different selection signature statistics. When examined with simulated data, DCMS consistently has a higher power than most of the single statistics and shows a reliable positional resolution. We illustrate the new statistic to the established selective sweep around the lactase gene in human HapMap data providing further evidence of the reliability of this new statistic. Then, we apply it to scan selection signatures in two chicken samples with diverse skin color. Our analysis suggests that a set of well-known genes such as BCO2, MC1R, ASIP and TYR were involved in the divergent selection for this trait.

Creation of a virtual cutaneous tissue bank

NASA Astrophysics Data System (ADS)

LaFramboise, William A.; Shah, Sujal; Hoy, R. W.; Letbetter, D.; Petrosko, P.; Vennare, R.; Johnson, Peter C.

2000-04-01

Cellular and non-cellular constituents of skin contain fundamental morphometric features and structural patterns that correlate with tissue function. High resolution digital image acquisitions performed using an automated system and proprietary software to assemble adjacent images and create a contiguous, lossless, digital representation of individual microscope slide specimens. Serial extraction, evaluation and statistical analysis of cutaneous feature is performed utilizing an automated analysis system, to derive normal cutaneous parameters comprising essential structural skin components. Automated digital cutaneous analysis allows for fast extraction of microanatomic dat with accuracy approximating manual measurement. The process provides rapid assessment of feature both within individual specimens and across sample populations. The images, component data, and statistical analysis comprise a bioinformatics database to serve as an architectural blueprint for skin tissue engineering and as a diagnostic standard of comparison for pathologic specimens.

Is there a relationship between periodontal disease and causes of death? A cross sectional study.

PubMed

Natto, Zuhair S; Aladmawy, Majdi; Alasqah, Mohammed; Papas, Athena

2015-01-01

The aim of this study was to evaluate whether there is any correlation between periodontal disease and mortality contributing factors, such as cardiovascular disease and diabetes mellitus in the elderly population. A dental evaluation was performed by a single examiner at Tufts University dental clinics for 284 patients. Periodontal assessments were performed by probing with a manual UNC-15 periodontal probe to measure pocket depth and clinical attachment level (CAL) at 6 sites. Causes of death abstracted from death certificate. Statistical analysis involved ANOVA, chi-square and multivariate logistic regression analysis. The demographics of the population sample indicated that, most were females (except for diabetes mellitus), white, married, completed 13 years of education and were 83 years old on average. CAL (continuous or dichotomous) and marital status attained statistical significance (p<0.05) in contingency table analysis (Chi-square for independence). Individuals with increased CAL were 2.16 times more likely (OR=2.16, 95% CI=1.47-3.17) to die due to CVD and this effect persisted even after control for age, marital status, gender, race, years of education (OR=2.03, 95% CI=1.35-3.03). CAL (continuous or dichotomous) was much higher among those who died due to diabetes mellitus or out of state of Massachusetts. However, these results were not statistically significant. The same pattern was observed with pocket depth (continuous or dichotomous), but these results were not statistically significant either. CAL seems to be more sensitive to chronic diseases than pocket depth. Among those conditions, cardiovascular disease has the strongest effect.

School Enrollment in Iraq during the U.S-Led Invasion: A Statistical Analysis

ERIC Educational Resources Information Center

Shafiq, M. Najeeb

2012-01-01

Little is known about the educational consequences in Iraq during the U.S.-led invasion of 2003-2010. This study examines school enrollment based on the 2007 Iraq Household Socio-Economic Survey. There are three main findings. First, a population-weighted analysis indicates that the school enrollment rate (72.3 percent) is lower than past Iraqi…

School Enrollment in Iraq during the U.S.-Led Invasion: A Statistical Analysis

ERIC Educational Resources Information Center

Shafiq, M. Najeeb

2013-01-01

Little is known about the educational consequences in Iraq during the U.S.-led invasion of 2003-2010. This study examines school enrollment based on the 2007 Iraq Household Socio-Economic Survey. There are three main findings. First, a population-weighted analysis indicates that the school enrollment rate (72.3%) is lower than past Iraqi rates but…

Helioseismology of pre-emerging active regions. III. Statistical analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnes, G.; Leka, K. D.; Braun, D. C.

The subsurface properties of active regions (ARs) prior to their appearance at the solar surface may shed light on the process of AR formation. Helioseismic holography has been applied to samples taken from two populations of regions on the Sun (pre-emergence and without emergence), each sample having over 100 members, that were selected to minimize systematic bias, as described in Paper I. Paper II showed that there are statistically significant signatures in the average helioseismic properties that precede the formation of an AR. This paper describes a more detailed analysis of the samples of pre-emergence regions and regions without emergencemore » based on discriminant analysis. The property that is best able to distinguish the populations is found to be the surface magnetic field, even a day before the emergence time. However, after accounting for the correlations between the surface field and the quantities derived from helioseismology, there is still evidence of a helioseismic precursor to AR emergence that is present for at least a day prior to emergence, although the analysis presented cannot definitively determine the subsurface properties prior to emergence due to the small sample sizes.« less

CONSPECIFIC ATTRACTION IN LOGGERHEAD SHRIKES: IMPLICATIONS FOR HABITAT CONSERVATION AND REINTRODUCTION

EPA Science Inventory

The loggerhead shrike, Lanius ludovicianus, is a declining songbird that forms breeding aggregations. Despite such reports from several populations, only one statistical analysis of loggerhead shrike territory distribution has been published to date. I use a spatio-temporal sim...

7 CFR 2.17 - Under Secretary for Rural Development.

Code of Federal Regulations, 2014 CFR

2014-01-01

... research and analysis, statistical programs, and associated service work related to rural people and the communities in which they live including rural industrialization; rural population and manpower; local... formulating manpower development and training policies. (13) Related to committee management. Establish and...

7 CFR 2.17 - Under Secretary for Rural Development.

Code of Federal Regulations, 2013 CFR

2013-01-01

... research and analysis, statistical programs, and associated service work related to rural people and the communities in which they live including rural industrialization; rural population and manpower; local... formulating manpower development and training policies. (13) Related to committee management. Establish and...

7 CFR 2.17 - Under Secretary for Rural Development.

Code of Federal Regulations, 2010 CFR

2010-01-01

... research and analysis, statistical programs, and associated service work related to rural people and the communities in which they live including rural industrialization; rural population and manpower; local... formulating manpower development and training policies. (13) Related to committee management. Establish and...

Approaches of researches in medical geography in Poland and Ukraine

NASA Astrophysics Data System (ADS)

Pantylej, Wiktoria

2008-01-01

This paper deals with the historical review of medical geography in the world, in Poland and in Ukraine. There are different approaches in medical geography: according to the research subject (ecological and economic approaches) and according to the current affairs of research (approach concerns sexuality, the age of the population and accordingly, accessibility of health care services to the population). To the author's mind, the most perspective approaches in medical geography in Poland and Ukraine are as follows: - integrative - dedicated to the health status of the population in connection with the quality and life level; - mathematical-statistical - connected with the problem of synthetic indexes of health status of the populations and factors influencing it, and with the problem of economic value of health and life of the population; - social-economic - the analysis of the influence of socioeconomic factors (such as wealth measure, rate of unemployment, work conditions and others) on public health; - ecological - connected with the researches dedicated to the analysis of environmental impact on public health status of the population; - demographical - the analysis of demographical factors of forming public health status; - social-psychological - health culture of the population, perception of the own health/morbidity and health care systems existing in different countries.

SDGs and Geospatial Frameworks: Data Integration in the United States

NASA Astrophysics Data System (ADS)

Trainor, T.

2016-12-01

Responding to the need to monitor a nation's progress towards meeting the Sustainable Development Goals (SDG) outlined in the 2030 U.N. Agenda requires the integration of earth observations with statistical information. The urban agenda proposed in SDG 11 challenges the global community to find a geospatial approach to monitor and measure inclusive, safe, resilient, and sustainable cities and communities. Target 11.7 identifies public safety, accessibility to green and public spaces, and the most vulnerable populations (i.e., women and children, older persons, and persons with disabilities) as the most important priorities of this goal. A challenge for both national statistical organizations and earth observation agencies in addressing SDG 11 is the requirement for detailed statistics at a sufficient spatial resolution to provide the basis for meaningful analysis of the urban population and city environments. Using an example for the city of Pittsburgh, this presentation proposes data and methods to illustrate how earth science and statistical data can be integrated to respond to Target 11.7. Finally, a preliminary series of data initiatives are proposed for extending this method to other global cities.

Guide to Using Onionskin Analysis Code (U)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fugate, Michael Lynn; Morzinski, Jerome Arthur

2016-09-15

This document is a guide to using R-code written for the purpose of analyzing onionskin experiments. We expect the user to be very familiar with statistical methods and the R programming language. For more details about onionskin experiments and the statistical methods mentioned in this document see Storlie, Fugate, et al. (2013). Engineers at LANL experiment with detonators and high explosives to assess performance. The experimental unit, called an onionskin, is a hemisphere consisting of a detonator and a booster pellet surrounded by explosive material. When the detonator explodes, a streak camera mounted above the pole of the hemisphere recordsmore » when the shock wave arrives at the surface. The output from the camera is a two-dimensional image that is transformed into a curve that shows the arrival time as a function of polar angle. The statistical challenge is to characterize a baseline population of arrival time curves and to compare the baseline curves to curves from a new, so-called, test series. The hope is that the new test series of curves is statistically similar to the baseline population.« less

Modeling the Space Debris Environment with MASTER-2009 and ORDEM2010

NASA Technical Reports Server (NTRS)

Flegel, S.; Gelhaus, J.; Wiedemann, C.; Mockel, M.; Vorsmann, P.; Krisko, P.; Xu, Y. -L.; Horstman, M. F.; Opiela, J. N.; Matney, M.;

[Intensification of post-traumatic stress disorder of Siberian deportees from the North-East region of Poland].

PubMed

Monieta, Adela; Anczurowski, Wojciech

2004-01-01

Presentation of Post-Traumatic Stress Disorder based on the approach of various authors concentrating, upon the concept of the American classification: DSM III (1980) and DSM IV (1994). We acknowledged the necessity of displaying empirical results of intensification of PTSD among the Siberian deportees population in the region of North-East part of Poland. In our analysis, we stressed the importance of the distant in time, psychological consequences of dwelling in extremely difficult living conditions that often threatened the life of those who had been deported to Siberia between 1939 and 1956. 40 "Siberian deportees" (20 men and 20 women) were examined. The method of PTSD-Interview (PTSD-I) was used here in order to obtain, in each individual case, the indicatory number indispensable for the statistical analysis. An average result of PTSD intensification in the case of women reaches a "very significant" level and in the case of men it is even higher. The disparity between the average results of women and of men are statistically significant (p<0.05). This research has confirmed the assumptions that suffering from trauma in the early stage of development (within the age range of 8-15) leaves a permanent mark in the human psyche. Statistical analysis revealed a high level of intensification of PTSD among the population of the "Siberian deportees" from the North-East region of Poland.

Determinants of health care expenditures and the contribution of associated factors: 16 cities and provinces in Korea, 2003-2010.

PubMed

Han, Kimyoung; Cho, Minho; Chun, Kihong

2013-11-01

The purpose of this study was to classify determinants of cost increases into two categories, negotiable factors and non-negotiable factors, in order to identify the determinants of health care expenditure increases and to clarify the contribution of associated factors selected based on a literature review. The data in this analysis was from the statistical yearbooks of National Health Insurance Service, the Economic Index from Statistics Korea and regional statistical yearbooks. The unit of analysis was the annual growth rate of variables of 16 cities and provinces from 2003 to 2010. First, multiple regression was used to identify the determinants of health care expenditures. We then used hierarchical multiple regression to calculate the contribution of associated factors. The changes of coefficients (R(2)) of predictors, which were entered into this analysis step by step based on the empirical evidence of the investigator could explain the contribution of predictors to increased medical cost. Health spending was mainly associated with the proportion of the elderly population, but the Medicare Economic Index (MEI) showed an inverse association. The contribution of predictors was as follows: the proportion of elderly in the population (22.4%), gross domestic product (GDP) per capita (4.5%), MEI (-12%), and other predictors (less than 1%). As Baby Boomers enter retirement, an increasing proportion of the population aged 65 and over and the GDP will continue to increase, thus accelerating the inflation of health care expenditures and precipitating a crisis in the health insurance system. Policy makers should consider providing comprehensive health services by an accountable care organization to achieve cost savings while ensuring high-quality care.

Association between periodontal disease and mortality in people with CKD: a meta-analysis of cohort studies.

PubMed

Zhang, Jian; Jiang, Hong; Sun, Min; Chen, Jianghua

2017-08-16

Periodontal disease occurs relatively prevalently in people with chronic kidney disease (CKD), but it remains indeterminate whether periodontal disease is an independent risk factor for premature death in this population. Interventions to reduce mortality in CKD population consistently yield to unsatisfactory results and new targets are necessitated. So this meta-analysis aimed to evaluate the association between periodontal disease and mortality in the CKD population. Pubmed, Embase, Web of Science, Scopus and abstracts from recent relevant meeting were searched by two authors independently. Relative risks (RRs) with 95% confidence intervals (CIs) were calculated for overall and subgroup meta-analyses. Statistical heterogeneity was explored by chi-square test and quantified by the I 2 statistic. Eight cohort studies comprising 5477 individuals with CKD were incorporated. The overall pooled data demonstrated that periodontal disease was associated with all-cause death in CKD population (RR, 1.254; 95% CI 1.046-1.503; P = 0.005), with a moderate heterogeneity, I 2  = 52.2%. However, no evident association was observed between periodontal disease and cardiovascular mortality (RR, 1.30, 95% CI, 0.82-2.06; P = 0.259). Besides, statistical heterogeneity was substantial (I 2  = 72.5%; P = 0.012). Associations for mortality were similar between subgroups, such as the different stages of CKD, adjustment for confounding factors. Specific to all-cause death, sensitivity and cumulative analyses both suggested that our results were robust. As for cardiovascular mortality, the association with periodontal disease needs to be further strengthened. We demonstrated that periodontal disease was associated with an increased risk of all-cause death in CKD people. Yet no adequate evidence suggested periodontal disease was also at elevated risk for cardiovascular death.

Genital Chlamydia Prevalence in Europe and Non-European High Income Countries: Systematic Review and Meta-Analysis

PubMed Central

Redmond, Shelagh M.; Alexander-Kisslig, Karin; Woodhall, Sarah C.; van den Broek, Ingrid V. F.; van Bergen, Jan; Ward, Helen; Uusküla, Anneli; Herrmann, Björn; Andersen, Berit; Götz, Hannelore M.; Sfetcu, Otilia; Low, Nicola

2015-01-01

Background Accurate information about the prevalence of Chlamydia trachomatis is needed to assess national prevention and control measures. Methods 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. Results 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). Conclusions 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. PMID:25615574

Mapping of epistatic quantitative trait loci in four-way crosses.

PubMed

He, Xiao-Hong; Qin, Hongde; Hu, Zhongli; Zhang, Tianzhen; Zhang, Yuan-Ming

2011-01-01

Four-way crosses (4WC) involving four different inbred lines often appear in plant and animal commercial breeding programs. Direct mapping of quantitative trait loci (QTL) in these commercial populations is both economical and practical. However, the existing statistical methods for mapping QTL in a 4WC population are built on the single-QTL genetic model. This simple genetic model fails to take into account QTL interactions, which play an important role in the genetic architecture of complex traits. In this paper, therefore, we attempted to develop a statistical method to detect epistatic QTL in 4WC population. Conditional probabilities of QTL genotypes, computed by the multi-point single locus method, were used to sample the genotypes of all putative QTL in the entire genome. The sampled genotypes were used to construct the design matrix for QTL effects. All QTL effects, including main and epistatic effects, were simultaneously estimated by the penalized maximum likelihood method. The proposed method was confirmed by a series of Monte Carlo simulation studies and real data analysis of cotton. The new method will provide novel tools for the genetic dissection of complex traits, construction of QTL networks, and analysis of heterosis.

An Analysis on the Unemployment Rate in the Philippines: A Time Series Data Approach

NASA Astrophysics Data System (ADS)

Urrutia, J. D.; Tampis, R. L.; E Atienza, JB

2017-03-01

This study aims to formulate a mathematical model for forecasting and estimating unemployment rate in the Philippines. Also, factors which can predict the unemployment is to be determined among the considered variables namely Labor Force Rate, Population, Inflation Rate, Gross Domestic Product, and Gross National Income. Granger-causal relationship and integration among the dependent and independent variables are also examined using Pairwise Granger-causality test and Johansen Cointegration Test. The data used were acquired from the Philippine Statistics Authority, National Statistics Office, and Bangko Sentral ng Pilipinas. Following the Box-Jenkins method, the formulated model for forecasting the unemployment rate is SARIMA (6, 1, 5) × (0, 1, 1)4 with a coefficient of determination of 0.79. The actual values are 99 percent identical to the predicted values obtained through the model, and are 72 percent closely relative to the forecasted ones. According to the results of the regression analysis, Labor Force Rate and Population are the significant factors of unemployment rate. Among the independent variables, Population, GDP, and GNI showed to have a granger-causal relationship with unemployment. It is also found that there are at least four cointegrating relations between the dependent and independent variables.

Evaluation of biological and male reproductive-function responses to potential lead exposures in 155-mm-howitzer crewmen. Technical report, Jul 90-Dec 91

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weyandt, T.B.

1992-01-01

A collaborative pilot study between the U.S. Army Biomedical Research and Development Laboratory and the National Institute for Occupational Safety and Health was designed to assess the fecundity of male artillery soldiers with potential exposures to airborne lead aerosols. Many soldiers in the initial control population reported possible job-related microwave exposure as radar equipment operators. As a result, a third group of soldiers without potential for lead or microwave exposure, but with similar duty-associated environmental exposure conditions, was selected as a comparison population. Blood hormone levels and semen analyses were conducted on artillerymen (n=30), radar equipment operators (n=20), and themore » comparison group (n=31). Analysis of the questionnaire information revealed that concern about fertility problems motivated participation of some soldiers with potential artillery or microwave exposures. Data analysis was complicated by the small study population size and the confounding variable of perceived infertility. Although the small number of subjects and infertility concerns somewhat compromise the statistical power and general applicability of the study, several statistically significant findings were identified.« less

Genetic polymorphisms of pharmacogenomic VIP variants in the Yi population from China.

PubMed

Yan, Mengdan; Li, Dianzhen; Zhao, Guige; Li, Jing; Niu, Fanglin; Li, Bin; Chen, Peng; Jin, Tianbo

2018-03-30

Drug response and target therapeutic dosage are different among individuals. The variability is largely genetically determined. With the development of pharmacogenetics and pharmacogenomics, widespread research have provided us a wealth of information on drug-related genetic polymorphisms, and the very important pharmacogenetic (VIP) variants have been identified for the major populations around the world whereas less is known regarding minorities in China, including the Yi ethnic group. Our research aims to screen the potential genetic variants in Yi population on pharmacogenomics and provide a theoretical basis for future medication guidance. In the present study, 80 VIP variants (selected from the PharmGKB database) were genotyped in 100 unrelated and healthy Yi adults recruited for our research. Through statistical analysis, we made a comparison between the Yi and other 11 populations listed in the HapMap database for significant SNPs detection. Two specific SNPs were subsequently enrolled in an observation on global allele distribution with the frequencies downloaded from ALlele FREquency Database. Moreover, F-statistics (Fst), genetic structure and phylogenetic tree analyses were conducted for determination of genetic similarity between the 12 ethnic groups. Using the χ2 tests, rs1128503 (ABCB1), rs7294 (VKORC1), rs9934438 (VKORC1), rs1540339 (VDR) and rs689466 (PTGS2) were identified as the significantly different loci for further analysis. The global allele distribution revealed that the allele "A" of rs1540339 and rs9934438 were more frequent in Yi people, which was consistent with the most populations in East Asia. F-statistics (Fst), genetic structure and phylogenetic tree analyses demonstrated that the Yi and CHD shared a closest relationship on their genetic backgrounds. Additionally, Yi was considered similar to the Han people from Shaanxi province among the domestic ethnic populations in China. Our results demonstrated significant differences on several polymorphic SNPs and supplement the pharmacogenomic information for the Yi population, which could provide new strategies for optimizing clinical medication in accordance with the genetic determinants of drug toxicity and efficacy. Copyright © 2018 Elsevier B.V. All rights reserved.

Age-Sex Structure of the Population and Demographic Processes in Environmentally Challenged Mining Region (on the example of Kemerovo region)

NASA Astrophysics Data System (ADS)

Leshukov, Timofey; Brel, Olga; Zaytseva, Anna; Kaizer, Philipp; Makarov, Kirill

2017-11-01

The main goal of the article is to show the influence of the age-sex structure of the population on the basic demographic processes in the Kemerovo region. During research the authors have established correlation links between the sex-age structure of the population and the main demographic indicators (birth and mortality rate, morbidity rate, migration and others) based on the analysis of official statistical data. The direct influence of internal and external factors on the age-sex structure of the population is revealed. Conclusions about the impact of demographic processes on the sex-age structure of the population of the Kemerovo region are drawn.

Analysis of bacterial populations in the environment using two-dimensional gel electrophoresis of genomic DNA and complementary DNA.

PubMed

Liu, Guo-Hua; Nakamura, Tatsuo; Amemiya, Takashi; Rajendran, Narasimmalu; Itoh, Kiminori

2011-01-01

Two-dimensional gel electrophoresis (2-DGE) mapping of genomic DNA and complementary DNA (cDNA) amplicons was attempted to analyze total and active bacterial populations within soil and activated sludge samples. Distinct differences in the number and species of bacterial populations and those that were metabolically active at the time of sampling were visually observed especially for the soil community. Statistical analyses and sequencing based on the 2-DGE data further revealed the relationships between total and active bacterial populations within each community. This high-resolution technique would be useful for obtaining a better understanding of bacterial population structures in the environment.

Application of Semiparametric Spline Regression Model in Analyzing Factors that In uence Population Density in Central Java

NASA Astrophysics Data System (ADS)

Sumantari, Y. D.; Slamet, I.; Sugiyanto

2017-06-01

Semiparametric regression is a statistical analysis method that consists of parametric and nonparametric regression. There are various approach techniques in nonparametric regression. One of the approach techniques is spline. Central Java is one of the most densely populated province in Indonesia. Population density in this province can be modeled by semiparametric regression because it consists of parametric and nonparametric component. Therefore, the purpose of this paper is to determine the factors that in uence population density in Central Java using the semiparametric spline regression model. The result shows that the factors which in uence population density in Central Java is Family Planning (FP) active participants and district minimum wage.

Propagation of population pharmacokinetic information using a Bayesian approach: comparison with meta-analysis.

PubMed

Dokoumetzidis, Aristides; Aarons, Leon

2005-08-01

We investigated the propagation of population pharmacokinetic information across clinical studies by applying Bayesian techniques. The aim was to summarize the population pharmacokinetic estimates of a study in appropriate statistical distributions in order to use them as Bayesian priors in consequent population pharmacokinetic analyses. Various data sets of simulated and real clinical data were fitted with WinBUGS, with and without informative priors. The posterior estimates of fittings with non-informative priors were used to build parametric informative priors and the whole procedure was carried on in a consecutive manner. The posterior distributions of the fittings with informative priors where compared to those of the meta-analysis fittings of the respective combinations of data sets. Good agreement was found, for the simulated and experimental datasets when the populations were exchangeable, with the posterior distribution from the fittings with the prior to be nearly identical to the ones estimated with meta-analysis. However, when populations were not exchangeble an alternative parametric form for the prior, the natural conjugate prior, had to be used in order to have consistent results. In conclusion, the results of a population pharmacokinetic analysis may be summarized in Bayesian prior distributions that can be used consecutively with other analyses. The procedure is an alternative to meta-analysis and gives comparable results. It has the advantage that it is faster than the meta-analysis, due to the large datasets used with the latter and can be performed when the data included in the prior are not actually available.

GenAlEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research—an update

PubMed Central

Peakall, Rod; Smouse, Peter E.

2012-01-01

Summary: GenAlEx: Genetic Analysis in Excel is a cross-platform package for population genetic analyses that runs within Microsoft Excel. GenAlEx offers analysis of diploid codominant, haploid and binary genetic loci and DNA sequences. Both frequency-based (F-statistics, heterozygosity, HWE, population assignment, relatedness) and distance-based (AMOVA, PCoA, Mantel tests, multivariate spatial autocorrelation) analyses are provided. New features include calculation of new estimators of population structure: G′ST, G′′ST, Jost’s Dest and F′ST through AMOVA, Shannon Information analysis, linkage disequilibrium analysis for biallelic data and novel heterogeneity tests for spatial autocorrelation analysis. Export to more than 30 other data formats is provided. Teaching tutorials and expanded step-by-step output options are included. The comprehensive guide has been fully revised. Availability and implementation: GenAlEx is written in VBA and provided as a Microsoft Excel Add-in (compatible with Excel 2003, 2007, 2010 on PC; Excel 2004, 2011 on Macintosh). GenAlEx, and supporting documentation and tutorials are freely available at: http://biology.anu.edu.au/GenAlEx. Contact: rod.peakall@anu.edu.au PMID:22820204

What population studies can do for business.

PubMed

Hugo, G

1991-05-01

This paper examines how specific skills essential to demography, the scientific study of human populations, can be useful in private and public sector planning. Over the past 2 decades, Australia's population has undergone profound transformations -- a shift to below replacement level fertility and a change in ethnic composition, to name a few. And these changes have reshaped the markets for goods, services, and labor. Because demography seeks to analyze and explain changes in the size, composition, and spatial distribution of people, this discipline requires certain skills that can be particularly valuable to both private and public sector planning. These skills include: 1) a sound knowledge of why and how populations change over time; 2) a wide range of concepts (the "cohort," for example) which allow demographers to analyze the dynamics of change in a population; 3) statistical techniques; and 4) life tables techniques. Having named the specific skills of demographers, the author identifies the areas of business and public administration where these skills can be most useful, areas that include the following: strategic long-term planning, marketing, market segmentation, small area analysis, household and family level analysis, projections and estimates, human resources analysis, and international population trends. Finally, the author discusses the implications of applied population analysis on the training of demographers in Australia, emphasizing the role of the Australian Population Association in improving the status of demography as an important planning tool.

Population Structure, Genetic Diversity and Molecular Marker-Trait Association Analysis for High Temperature Stress Tolerance in Rice

PubMed Central

Barik, Saumya Ranjan; Sahoo, Ambika; Mohapatra, Sudipti; Nayak, Deepak Kumar; Mahender, Anumalla; Meher, Jitandriya; Anandan, Annamalai

2016-01-01

Rice exhibits enormous genetic diversity, population structure and molecular marker-traits associated with abiotic stress tolerance to high temperature stress. A set of breeding lines and landraces representing 240 germplasm lines were studied. Based on spikelet fertility percent under high temperature, tolerant genotypes were broadly classified into four classes. Genetic diversity indicated a moderate level of genetic base of the population for the trait studied. Wright’s F statistic estimates showed a deviation of Hardy-Weinberg expectation in the population. The analysis of molecular variance revealed 25 percent variation between population, 61 percent among individuals and 14 percent within individuals in the set. The STRUCTURE analysis categorized the entire population into three sub-populations and suggested that most of the landraces in each sub-population had a common primary ancestor with few admix individuals. The composition of materials in the panel showed the presence of many QTLs representing the entire genome for the expression of tolerance. The strongly associated marker RM547 tagged with spikelet fertility under stress and the markers like RM228, RM205, RM247, RM242, INDEL3 and RM314 indirectly controlling the high temperature stress tolerance were detected through both mixed linear model and general linear model TASSEL analysis. These markers can be deployed as a resource for marker-assisted breeding program of high temperature stress tolerance. PMID:27494320

Population Structure, Genetic Diversity and Molecular Marker-Trait Association Analysis for High Temperature Stress Tolerance in Rice.

PubMed

Pradhan, Sharat Kumar; Barik, Saumya Ranjan; Sahoo, Ambika; Mohapatra, Sudipti; Nayak, Deepak Kumar; Mahender, Anumalla; Meher, Jitandriya; Anandan, Annamalai; Pandit, Elssa

2016-01-01

Rice exhibits enormous genetic diversity, population structure and molecular marker-traits associated with abiotic stress tolerance to high temperature stress. A set of breeding lines and landraces representing 240 germplasm lines were studied. Based on spikelet fertility percent under high temperature, tolerant genotypes were broadly classified into four classes. Genetic diversity indicated a moderate level of genetic base of the population for the trait studied. Wright's F statistic estimates showed a deviation of Hardy-Weinberg expectation in the population. The analysis of molecular variance revealed 25 percent variation between population, 61 percent among individuals and 14 percent within individuals in the set. The STRUCTURE analysis categorized the entire population into three sub-populations and suggested that most of the landraces in each sub-population had a common primary ancestor with few admix individuals. The composition of materials in the panel showed the presence of many QTLs representing the entire genome for the expression of tolerance. The strongly associated marker RM547 tagged with spikelet fertility under stress and the markers like RM228, RM205, RM247, RM242, INDEL3 and RM314 indirectly controlling the high temperature stress tolerance were detected through both mixed linear model and general linear model TASSEL analysis. These markers can be deployed as a resource for marker-assisted breeding program of high temperature stress tolerance.

Utilization of outpatient services in refugee settlement health facilities: a comparison by age, gender, and refugee versus host national status

PubMed Central

2011-01-01

Background Comparisons between refugees receiving health care in settlement-based facilities and persons living in host communities have found that refugees have better health outcomes. However, data that compares utilization of health services between refugees and the host population, and across refugee settlements, countries and regions is limited. The paper will address this information gap. The analysis in this paper uses data from the United Nations High Commissioner of Refugees (UNHCR) Health Information System (HIS). Methods Data about settlement populations and the use of outpatient health services were exported from the UNHCR health information system database. Tableau Desktop was used to explore the data. STATA was used for data cleaning and statistical analysis. Differences in various indicators of the use of health services by region, gender, age groups, and status (host national vs. refugee population) were analyzed for statistical significance using generalized estimating equation models that adjusted for correlated data within refugee settlements over time. Results Eighty-one refugee settlements were included in this study and an average population of 1.53 million refugees was receiving outpatient health services between 2008 and 2009. The crude utilization rate among refugees is 2.2 visits per person per year across all settlements. The refugee utilization rate in Asia (3.5) was higher than in Africa on average (1.8). Among refugees, females have a statistically significant higher utilization rate than males (2.4 visits per person per year vs. 2.1). The proportion of new outpatient attributable to refugees is higher than that attributable to host nationals. In the Asian settlements, only 2% outpatient visits, on average, were attributable to host community members. By contrast, in Africa, the proportion of new outpatient (OPD) visits by host nationals was 21% on average; in many Ugandan settlements, the proportion of outpatient visits attributable to host community members was higher than that for refugees. There was no statistically significant difference between the size of the male and female populations across refugee settlements. Across all settlements reporting to the UNHCR database, the percent of the refugee population that was less than five years of age is 16% on average. Conclusions The availability of a centralized database of health information across UNHCR-supported refugee settlements is a rich resource. The SPHERE standard for emergencies of 1-4 visits per person per year appears to be relevant for Asia in the post-emergency phase, but not for Africa. In Africa, a post-emergency standard of 1-2 visits per person per year should be considered. Although it is often assumed that the size of the female population in refugee settlements is higher than males, we found no statistically significant difference between the size of the male and female populations in refugee settlements overall. Another assumption---that the under-fives make up 20% of the settlement population during the emergency phase---does not appear to hold for the post-emergency phase; under-fives made up about 16% of refugee settlement populations. PMID:21936911

Evaluating optimal therapy robustness by virtual expansion of a sample population, with a case study in cancer immunotherapy

PubMed Central

Barish, Syndi; Ochs, Michael F.; Sontag, Eduardo D.; Gevertz, Jana L.

2017-01-01

Cancer is a highly heterogeneous disease, exhibiting spatial and temporal variations that pose challenges for designing robust therapies. Here, we propose the VEPART (Virtual Expansion of Populations for Analyzing Robustness of Therapies) technique as a platform that integrates experimental data, mathematical modeling, and statistical analyses for identifying robust optimal treatment protocols. VEPART begins with time course experimental data for a sample population, and a mathematical model fit to aggregate data from that sample population. Using nonparametric statistics, the sample population is amplified and used to create a large number of virtual populations. At the final step of VEPART, robustness is assessed by identifying and analyzing the optimal therapy (perhaps restricted to a set of clinically realizable protocols) across each virtual population. As proof of concept, we have applied the VEPART method to study the robustness of treatment response in a mouse model of melanoma subject to treatment with immunostimulatory oncolytic viruses and dendritic cell vaccines. Our analysis (i) showed that every scheduling variant of the experimentally used treatment protocol is fragile (nonrobust) and (ii) discovered an alternative region of dosing space (lower oncolytic virus dose, higher dendritic cell dose) for which a robust optimal protocol exists. PMID:28716945

Hierarchical model analysis of the Atlantic Flyway Breeding Waterfowl Survey

USGS Publications Warehouse

Sauer, John R.; Zimmerman, Guthrie S.; Klimstra, Jon D.; Link, William A.

2014-01-01

We used log-linear hierarchical models to analyze data from the Atlantic Flyway Breeding Waterfowl Survey. The survey has been conducted by state biologists each year since 1989 in the northeastern United States from Virginia north to New Hampshire and Vermont. Although yearly population estimates from the survey are used by the United States Fish and Wildlife Service for estimating regional waterfowl population status for mallards (Anas platyrhynchos), black ducks (Anas rubripes), wood ducks (Aix sponsa), and Canada geese (Branta canadensis), they are not routinely adjusted to control for time of day effects and other survey design issues. The hierarchical model analysis permits estimation of year effects and population change while accommodating the repeated sampling of plots and controlling for time of day effects in counting. We compared population estimates from the current stratified random sample analysis to population estimates from hierarchical models with alternative model structures that describe year to year changes as random year effects, a trend with random year effects, or year effects modeled as 1-year differences. Patterns of population change from the hierarchical model results generally were similar to the patterns described by stratified random sample estimates, but significant visibility differences occurred between twilight to midday counts in all species. Controlling for the effects of time of day resulted in larger population estimates for all species in the hierarchical model analysis relative to the stratified random sample analysis. The hierarchical models also provided a convenient means of estimating population trend as derived statistics from the analysis. We detected significant declines in mallard and American black ducks and significant increases in wood ducks and Canada geese, a trend that had not been significant for 3 of these 4 species in the prior analysis. We recommend using hierarchical models for analysis of the Atlantic Flyway Breeding Waterfowl Survey.

Optimization of the p-xylene oxidation process by a multi-objective differential evolution algorithm with adaptive parameters co-derived with the population-based incremental learning algorithm

NASA Astrophysics Data System (ADS)

Guo, Zhan; Yan, Xuefeng

2018-04-01

Different operating conditions of p-xylene oxidation have different influences on the product, purified terephthalic acid. It is necessary to obtain the optimal combination of reaction conditions to ensure the quality of the products, cut down on consumption and increase revenues. A multi-objective differential evolution (MODE) algorithm co-evolved with the population-based incremental learning (PBIL) algorithm, called PBMODE, is proposed. The PBMODE algorithm was designed as a co-evolutionary system. Each individual has its own parameter individual, which is co-evolved by PBIL. PBIL uses statistical analysis to build a model based on the corresponding symbiotic individuals of the superior original individuals during the main evolutionary process. The results of simulations and statistical analysis indicate that the overall performance of the PBMODE algorithm is better than that of the compared algorithms and it can be used to optimize the operating conditions of the p-xylene oxidation process effectively and efficiently.

Allelic Prevalence of ABO Blood Group Genes in Iranian Azari Population.

PubMed

Nojavan, Mohammad; Shamsasenjan, Karrim; Movassaghpour, Ali Akbar; Akbarzadehlaleh, Parvin; Torabi, Seyd Esmail; Ghojazadeh, Morteza

2012-01-01

ABO blood group system is the most important blood group in transfusion and has been widely used in population studies. Several molecular techniques for ABO allele's detection are widely used for distinguishing various alleles of glycosyl transferase locus on chromosome 9. 744 randomly selected samples from Azari donors of East Azerbaijan province (Iran) were examined using well-adjusted multiplex allele- specific PCR ABO genotyping technique. The results were consistent for all individuals. The ABO blood group genotype of 744 healthy Azari blood donors was: 25.8% AA/AO (2), 7.6% AO (1), 1.6% BB, 11.3% B0 (1), 10% AB, 9.3% 0(1)0(1) and 15.3%0(1)0(2). The highest genotype frequency belonged to O01/O02 genotype (15.3%) and the lowest frequency belonged to A101/A102 genotype (0.4%). The frequencies of ABO alleles didn't show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05). The frequencies of ABO alleles didn't show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05).

Multi-Genetic Marker Approach and Spatio-Temporal Analysis Suggest There Is a Single Panmictic Population of Swordfish Xiphias gladius in the Indian Ocean

PubMed Central

Muths, Delphine; Le Couls, Sarah; Evano, Hugues; Grewe, Peter; Bourjea, Jerome

2013-01-01

Genetic population structure of swordfish Xiphias gladius was examined based on 2231 individual samples, collected mainly between 2009 and 2010, among three major sampling areas within the Indian Ocean (IO; twelve distinct sites), Atlantic (two sites) and Pacific (one site) Oceans using analysis of nineteen microsatellite loci (n = 2146) and mitochondrial ND2 sequences (n = 2001) data. Sample collection was stratified in time and space in order to investigate the stability of the genetic structure observed with a special focus on the South West Indian Ocean. Significant AMOVA variance was observed for both markers indicating genetic population subdivision was present between oceans. Overall value of F-statistics for ND2 sequences confirmed that Atlantic and Indian Oceans swordfish represent two distinct genetic stocks. Indo-Pacific differentiation was also significant but lower than that observed between Atlantic and Indian Oceans. However, microsatellite F-statistics failed to reveal structure even at the inter-oceanic scale, indicating that resolving power of our microsatellite loci was insufficient for detecting population subdivision. At the scale of the Indian Ocean, results obtained from both markers are consistent with swordfish belonging to a single unique panmictic population. Analyses partitioned by sampling area, season, or sex also failed to identify any clear structure within this ocean. Such large spatial and temporal homogeneity of genetic structure, observed for such a large highly mobile pelagic species, suggests as satisfactory to consider swordfish as a single panmictic population in the Indian Ocean. PMID:23717447

Genetic differentiation of the stingless bee Tetragonula pagdeni in Thailand using SSCP analysis of a large subunit of mitochondrial ribosomal DNA.

PubMed

Thummajitsakul, Sirikul; Klinbunga, Sirawut; Sittipraneed, Siriporn

2011-08-01

Genetic diversity and population differentiation of the stingless bee Tetragonula pagdeni (Schwarz) was assessed using single-strand conformational polymorphism (SSCP) analysis of a large subunit of the ribosomal RNA gene (16S rRNA). High levels of genetic variation among individuals within each population (North, Northeast, Central, Prachuap Khiri Khan, Chumphon, and Peninsular Thailand) of T. pagdeni were observed. Analysis of molecular variance indicated significant genetic differentiation among the six geographic populations (Φ (PT) = 0.28, P < 0.001) and between samples collected from north and south of the Isthmus of Kra (Φ (PT) = 0.18, P < 0.001). In addition, Φ (PT) values between all pairwise comparisons were statistically significant (P < 0.01), indicating strong degrees of intraspecific population differentiation. Therefore, PCR-SSCP is a simple and cost-effective technique applicable for routine population genetic analyses in T. pagdeni and other stingless bees. The results also provide an important baseline for the conservation and management of this ecologically important species.

Detection of reflecting surfaces by a statistical model

NASA Astrophysics Data System (ADS)

He, Qiang; Chu, Chee-Hung H.

2009-02-01

Remote sensing is widely used assess the destruction from natural disasters and to plan relief and recovery operations. How to automatically extract useful features and segment interesting objects from digital images, including remote sensing imagery, becomes a critical task for image understanding. Unfortunately, current research on automated feature extraction is ignorant of contextual information. As a result, the fidelity of populating attributes corresponding to interesting features and objects cannot be satisfied. In this paper, we present an exploration on meaningful object extraction integrating reflecting surfaces. Detection of specular reflecting surfaces can be useful in target identification and then can be applied to environmental monitoring, disaster prediction and analysis, military, and counter-terrorism. Our method is based on a statistical model to capture the statistical properties of specular reflecting surfaces. And then the reflecting surfaces are detected through cluster analysis.

Social inequalities in alcohol consumption in the Czech Republic: a multilevel analysis.

PubMed

Dzúrová, Dagmara; Spilková, Jana; Pikhart, Hynek

2010-05-01

Czech Republic traditionally ranks among the countries with the highest alcohol, consumption. This paper examines both risk and protective factors for frequent of alcohol, consumption in the Czech population using multilevel analysis. Risk factors were measured at the, individual level and at the area level. The individual-level data were obtained from a survey for a, sample of 3526 respondents aged 18-64 years. The area-level data were obtained from the Czech, Statistical Office. The group most inclinable to risk alcohol consumption and binge drinking are mainly, men, who live as single, with low education and also unemployed. Only the variable for divorce rate, showed statistical significance at both levels, thus the individual and the aggregated one. No cross-level interactions were found to be statistically significant. Copyright 2010 Elsevier Ltd. All rights reserved.

Computing Science and Statistics: Volume 24. Graphics and Visualization

DTIC Science & Technology

1993-03-20

r, is set to 3.569, the population examples include: kneading ingredients into a bread eventually oscillates about 16 fixed values. However the dough ...34fun statistics". My goal is to offer leagues I said in jest "After all, regression analysis is you the equivalent of a fortune cookie which clearly is... cookie of the night reads: One problem that statisticians traditionally seem to "You have good friends who will come to your aid in have is that they

An exploration of counterfeit medicine surveillance strategies guided by geospatial analysis: lessons learned from counterfeit Avastin detection in the US drug supply chain.

PubMed

Cuomo, Raphael E; Mackey, Tim K

2014-12-02

To explore healthcare policy and system improvements that would more proactively respond to future penetration of counterfeit cancer medications in the USA drug supply chain using geospatial analysis. A statistical and geospatial analysis of areas that received notices from the Food and Drug Administration (FDA) about the possibility of counterfeit Avastin penetrating the US drug supply chain. Data from FDA warning notices were compared to data from 44 demographic variables available from the US Census Bureau via correlation, means testing and geospatial visualisation. Results were interpreted in light of existing literature in order to recommend improvements to surveillance of counterfeit medicines. This study analysed 791 distinct healthcare provider addresses that received FDA warning notices across 30,431 zip codes in the USA. Statistical outputs were Pearson's correlation coefficients and t values. Geospatial outputs were cartographic visualisations. These data were used to generate the overarching study outcome, which was a recommendation for a strategy for drug safety surveillance congruent with existing literature on counterfeit medication. Zip codes with greater numbers of individuals age 65+ and greater numbers of ethnic white individuals were most correlated with receipt of a counterfeit Avastin notice. Geospatial visualisations designed in conjunction with statistical analysis of demographic variables appeared more capable of suggesting areas and populations that may be at risk for undetected counterfeit Avastin penetration. This study suggests that dual incorporation of statistical and geospatial analysis in surveillance of counterfeit medicine may be helpful in guiding efforts to prevent, detect and visualise counterfeit medicines penetrations in the US drug supply chain and other settings. Importantly, the information generated by these analyses could be utilised to identify at-risk populations associated with demographic characteristics. Stakeholders should explore these results as another tool to improve on counterfeit medicine surveillance. 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.

A Powerful Procedure for Pathway-Based Meta-analysis Using Summary Statistics Identifies 43 Pathways Associated with Type II Diabetes in European Populations.

PubMed

Zhang, Han; Wheeler, William; Hyland, Paula L; Yang, Yifan; Shi, Jianxin; Chatterjee, Nilanjan; Yu, Kai

2016-06-01

Meta-analysis of multiple genome-wide association studies (GWAS) has become an effective approach for detecting single nucleotide polymorphism (SNP) associations with complex traits. However, it is difficult to integrate the readily accessible SNP-level summary statistics from a meta-analysis into more powerful multi-marker testing procedures, which generally require individual-level genetic data. We developed a general procedure called Summary based Adaptive Rank Truncated Product (sARTP) for conducting gene and pathway meta-analysis that uses only SNP-level summary statistics in combination with genotype correlation estimated from a panel of individual-level genetic data. We demonstrated the validity and power advantage of sARTP through empirical and simulated data. We conducted a comprehensive pathway-based meta-analysis with sARTP on type 2 diabetes (T2D) by integrating SNP-level summary statistics from two large studies consisting of 19,809 T2D cases and 111,181 controls with European ancestry. Among 4,713 candidate pathways from which genes in neighborhoods of 170 GWAS established T2D loci were excluded, we detected 43 T2D globally significant pathways (with Bonferroni corrected p-values < 0.05), which included the insulin signaling pathway and T2D pathway defined by KEGG, as well as the pathways defined according to specific gene expression patterns on pancreatic adenocarcinoma, hepatocellular carcinoma, and bladder carcinoma. Using summary data from 8 eastern Asian T2D GWAS with 6,952 cases and 11,865 controls, we showed 7 out of the 43 pathways identified in European populations remained to be significant in eastern Asians at the false discovery rate of 0.1. We created an R package and a web-based tool for sARTP with the capability to analyze pathways with thousands of genes and tens of thousands of SNPs.

A Powerful Procedure for Pathway-Based Meta-analysis Using Summary Statistics Identifies 43 Pathways Associated with Type II Diabetes in European Populations

PubMed Central

Zhang, Han; Wheeler, William; Hyland, Paula L.; Yang, Yifan; Shi, Jianxin; Chatterjee, Nilanjan; Yu, Kai

2016-01-01

Meta-analysis of multiple genome-wide association studies (GWAS) has become an effective approach for detecting single nucleotide polymorphism (SNP) associations with complex traits. However, it is difficult to integrate the readily accessible SNP-level summary statistics from a meta-analysis into more powerful multi-marker testing procedures, which generally require individual-level genetic data. We developed a general procedure called Summary based Adaptive Rank Truncated Product (sARTP) for conducting gene and pathway meta-analysis that uses only SNP-level summary statistics in combination with genotype correlation estimated from a panel of individual-level genetic data. We demonstrated the validity and power advantage of sARTP through empirical and simulated data. We conducted a comprehensive pathway-based meta-analysis with sARTP on type 2 diabetes (T2D) by integrating SNP-level summary statistics from two large studies consisting of 19,809 T2D cases and 111,181 controls with European ancestry. Among 4,713 candidate pathways from which genes in neighborhoods of 170 GWAS established T2D loci were excluded, we detected 43 T2D globally significant pathways (with Bonferroni corrected p-values < 0.05), which included the insulin signaling pathway and T2D pathway defined by KEGG, as well as the pathways defined according to specific gene expression patterns on pancreatic adenocarcinoma, hepatocellular carcinoma, and bladder carcinoma. Using summary data from 8 eastern Asian T2D GWAS with 6,952 cases and 11,865 controls, we showed 7 out of the 43 pathways identified in European populations remained to be significant in eastern Asians at the false discovery rate of 0.1. We created an R package and a web-based tool for sARTP with the capability to analyze pathways with thousands of genes and tens of thousands of SNPs. PMID:27362418

Inferring Demographic History Using Two-Locus Statistics.

PubMed

Ragsdale, Aaron P; Gutenkunst, Ryan N

2017-06-01

Population demographic history may be learned from contemporary genetic variation data. Methods based on aggregating the statistics of many single loci into an allele frequency spectrum (AFS) have proven powerful, but such methods ignore potentially informative patterns of linkage disequilibrium (LD) between neighboring loci. To leverage such patterns, we developed a composite-likelihood framework for inferring demographic history from aggregated statistics of pairs of loci. Using this framework, we show that two-locus statistics are more sensitive to demographic history than single-locus statistics such as the AFS. In particular, two-locus statistics escape the notorious confounding of depth and duration of a bottleneck, and they provide a means to estimate effective population size based on the recombination rather than mutation rate. We applied our approach to a Zambian population of Drosophila melanogaster Notably, using both single- and two-locus statistics, we inferred a substantially lower ancestral effective population size than previous works and did not infer a bottleneck history. Together, our results demonstrate the broad potential for two-locus statistics to enable powerful population genetic inference. Copyright © 2017 by the Genetics Society of America.

Distribution of lod scores in oligogenic linkage analysis.

PubMed

Williams, J T; North, K E; Martin, L J; Comuzzie, A G; Göring, H H; Blangero, J

2001-01-01

In variance component oligogenic linkage analysis it can happen that the residual additive genetic variance bounds to zero when estimating the effect of the ith quantitative trait locus. Using quantitative trait Q1 from the Genetic Analysis Workshop 12 simulated general population data, we compare the observed lod scores from oligogenic linkage analysis with the empirical lod score distribution under a null model of no linkage. We find that zero residual additive genetic variance in the null model alters the usual distribution of the likelihood-ratio statistic.

[Genetic polymorphism of Tulipa gesneriana L. evaluated on the basis of the ISSR marking data].

PubMed

Kashin, A S; Kritskaya, T A; Schanzer, I A

2016-10-01

Using the method of ISSR analysis, the genetic diversity of 18 natural populations of Tulipa gesneriana L. from the north of the Lower Volga region was examined. The ten ISSR primers used in the study provided identification of 102 PCR fragments, of which 50 were polymorphic (49.0%). According to the proportion of polymorphic markers, two population groups were distinguished: (1) the populations in which the proportion of polymorphic markers ranged from 0.35 to 0.41; (2) the populations in which the proportion of polymorphic markers ranged from 0.64 to 0.85. UPGMA clustering analysis provided subdivision of the sample into two large clusters. The unrooted tree constructed using the Neighbor Joining algorithm had similar topology. The first cluster included slightly variable populations and the second cluster included highly variable populations. The AMOVA analysis showed statistically significant differences (F CT = 0.430; p = 0.000) between the two groups. Local populations are considerably genetically differentiated from each other (F ST = 0.632) and have almost no links via modern gene flow, as evidenced by the results of the Mantel test (r =–0.118; p = 0.819). It is suggested that the degree of genetic similarities and differences between the populations depends on the time and the species dispersal patterns on these territories.

Population Genetics of Identifiler System in Malaysia.

PubMed

Nakamura, Yasutaka; Samejima, Michinaga; Minaguchi, Kiyoshi; Nambiar, Phrabhakaran

2016-01-01

Short tandem repeat (STR) polymorphisms were investigated in 341 unrelated Malay individuals (218 males and 123 females) living in or around Kuala Lumpur by using a forensic analysts kit. The following STRs were targeted: D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA. The purpose of this study was to elucidate population genetics in Malaysia and calculate statistical parameters for forensic and anthropological research. Data on these STRs in the target population were obtained and subjected to statistical analysis. Accordance with the Hardy-Weinberg equilibrium was proven for all the loci targeted. The combined power of discrimination was greater than 0.9999999999, indicating that this multiplex system is an excellent tool for forensic casework. The allele frequency in the data were weighed against that in four other local populations (Chinese, Iranian, Belgian, and African). The average coefficient of correlation was strongest in the order of Africa (0.092522), Belgium (0.264822), Iran (0.404363), and China (0.706661). These results are consistent with what is known about the anthropological history of and prehistoric human migration in the Malay region. We believe that these data offer a valuable anthropological resource, being applicable to the statistical evaluation of DNA evidence in human identification, as well as the determination of ethnicity in healthy populations.

Viability of in-house datamarting approaches for population genetics analysis of SNP genotypes

PubMed Central

Amigo, Jorge; Phillips, Christopher; Salas, Antonio; Carracedo, Ángel

2009-01-01

Background Databases containing very large amounts of SNP (Single Nucleotide Polymorphism) data are now freely available for researchers interested in medical and/or population genetics applications. While many of these SNP repositories have implemented data retrieval tools for general-purpose mining, these alone cannot cover the broad spectrum of needs of most medical and population genetics studies. Results To address this limitation, we have built in-house customized data marts from the raw data provided by the largest public databases. In particular, for population genetics analysis based on genotypes we have built a set of data processing scripts that deal with raw data coming from the major SNP variation databases (e.g. HapMap, Perlegen), stripping them into single genotypes and then grouping them into populations, then merged with additional complementary descriptive information extracted from dbSNP. This allows not only in-house standardization and normalization of the genotyping data retrieved from different repositories, but also the calculation of statistical indices from simple allele frequency estimates to more elaborate genetic differentiation tests within populations, together with the ability to combine population samples from different databases. Conclusion The present study demonstrates the viability of implementing scripts for handling extensive datasets of SNP genotypes with low computational costs, dealing with certain complex issues that arise from the divergent nature and configuration of the most popular SNP repositories. The information contained in these databases can also be enriched with additional information obtained from other complementary databases, in order to build a dedicated data mart. Updating the data structure is straightforward, as well as permitting easy implementation of new external data and the computation of supplementary statistical indices of interest. PMID:19344481

Viability of in-house datamarting approaches for population genetics analysis of SNP genotypes.

PubMed

Amigo, Jorge; Phillips, Christopher; Salas, Antonio; Carracedo, Angel

2009-03-19

Databases containing very large amounts of SNP (Single Nucleotide Polymorphism) data are now freely available for researchers interested in medical and/or population genetics applications. While many of these SNP repositories have implemented data retrieval tools for general-purpose mining, these alone cannot cover the broad spectrum of needs of most medical and population genetics studies. To address this limitation, we have built in-house customized data marts from the raw data provided by the largest public databases. In particular, for population genetics analysis based on genotypes we have built a set of data processing scripts that deal with raw data coming from the major SNP variation databases (e.g. HapMap, Perlegen), stripping them into single genotypes and then grouping them into populations, then merged with additional complementary descriptive information extracted from dbSNP. This allows not only in-house standardization and normalization of the genotyping data retrieved from different repositories, but also the calculation of statistical indices from simple allele frequency estimates to more elaborate genetic differentiation tests within populations, together with the ability to combine population samples from different databases. The present study demonstrates the viability of implementing scripts for handling extensive datasets of SNP genotypes with low computational costs, dealing with certain complex issues that arise from the divergent nature and configuration of the most popular SNP repositories. The information contained in these databases can also be enriched with additional information obtained from other complementary databases, in order to build a dedicated data mart. Updating the data structure is straightforward, as well as permitting easy implementation of new external data and the computation of supplementary statistical indices of interest.

Tree-space statistics and approximations for large-scale analysis of anatomical trees.

PubMed

Feragen, Aasa; Owen, Megan; Petersen, Jens; Wille, Mathilde M W; Thomsen, Laura H; Dirksen, Asger; de Bruijne, Marleen

2013-01-01

Statistical analysis of anatomical trees is hard to perform due to differences in the topological structure of the trees. In this paper we define statistical properties of leaf-labeled anatomical trees with geometric edge attributes by considering the anatomical trees as points in the geometric space of leaf-labeled trees. This tree-space is a geodesic metric space where any two trees are connected by a unique shortest path, which corresponds to a tree deformation. However, tree-space is not a manifold, and the usual strategy of performing statistical analysis in a tangent space and projecting onto tree-space is not available. Using tree-space and its shortest paths, a variety of statistical properties, such as mean, principal component, hypothesis testing and linear discriminant analysis can be defined. For some of these properties it is still an open problem how to compute them; others (like the mean) can be computed, but efficient alternatives are helpful in speeding up algorithms that use means iteratively, like hypothesis testing. In this paper, we take advantage of a very large dataset (N = 8016) to obtain computable approximations, under the assumption that the data trees parametrize the relevant parts of tree-space well. Using the developed approximate statistics, we illustrate how the structure and geometry of airway trees vary across a population and show that airway trees with Chronic Obstructive Pulmonary Disease come from a different distribution in tree-space than healthy ones. Software is available from http://image.diku.dk/aasa/software.php.

Public and patient involvement in quantitative health research: A statistical perspective.

PubMed

Hannigan, Ailish

2018-06-19

The majority of studies included in recent reviews of impact for public and patient involvement (PPI) in health research had a qualitative design. PPI in solely quantitative designs is underexplored, particularly its impact on statistical analysis. Statisticians in practice have a long history of working in both consultative (indirect) and collaborative (direct) roles in health research, yet their perspective on PPI in quantitative health research has never been explicitly examined. To explore the potential and challenges of PPI from a statistical perspective at distinct stages of quantitative research, that is sampling, measurement and statistical analysis, distinguishing between indirect and direct PPI. Statistical analysis is underpinned by having a representative sample, and a collaborative or direct approach to PPI may help achieve that by supporting access to and increasing participation of under-represented groups in the population. Acknowledging and valuing the role of lay knowledge of the context in statistical analysis and in deciding what variables to measure may support collective learning and advance scientific understanding, as evidenced by the use of participatory modelling in other disciplines. A recurring issue for quantitative researchers, which reflects quantitative sampling methods, is the selection and required number of PPI contributors, and this requires further methodological development. Direct approaches to PPI in quantitative health research may potentially increase its impact, but the facilitation and partnership skills required may require further training for all stakeholders, including statisticians. © 2018 The Authors Health Expectations published by John Wiley & Sons Ltd.

Impact of some types of mass gatherings on current suicide risk in an urban population: statistical and negative binominal regression analysis of time series

PubMed Central

2014-01-01

Background Many studies have investigated the impact of a wide range of social events on suicide-related behaviour. However, these studies have predominantly examined national events. The aim of this study is to provide a statistical evaluation of the relationship between mass gatherings in some relatively small urban sub-populations and the general suicide rates of a major city. Methods The data were gathered in the Ukrainian city of Dnipropetrovsk, with a population of 1 million people, in 2005–2010. Suicide attempts, suicides, and the total amount of suicide-related behaviours were registered daily for each sex. Bivariate and multivariate statistical analysis, including negative binomial regression, were applied to assess the risk of suicide-related behaviour in the city’s general population for 7 days before and after 427 mass gatherings, such as concerts, football games, and non-regular mass events organized by the Orthodox Church and new religious movements. Results The bivariate and multivariate statistical analyses found significant changes in some suicide-related behaviour rates in the city’s population after certain kinds of mass gatherings. In particular, we observed an increased relative risk (RR) of male suicide-related behaviour after a home defeat of the local football team (RR = 1.32, p = 0.047; regression coefficient beta = 0.371, p = 0.002), and an increased risk of male suicides (RR = 1.29, p = 0.006; beta =0.255, p = 0.002), male suicide-related behaviour (RR = 1.25, p = 0.019; beta =0.251, p < 0.001), and total suicide-related behaviour (RR = 1.23 p < 0.001; beta =0.187, p < 0.001) after events organized by the new religious movements. Conclusions Although football games and mass events organized by new religious movements involved a relatively small part of an urban population (1.6 and 0.3%, respectively), we observed a significant increase of the some suicide-related behaviour rates in the whole population. It is likely that the observed effect on suicide-related behaviour is related to one’s personal presence at the event rather than to its broadcast. Our findings can be explained largely in terms of Gabennesch’s theory of the ‘broken-promises effect’ with regard to intra- and interpersonal conflict and, in terms of crowd behaviour effects. PMID:24708574

Statistical power and effect sizes of depression research in Japan.

PubMed

Okumura, Yasuyuki; Sakamoto, Shinji

2011-06-01

Few studies have been conducted on the rationales for using interpretive guidelines for effect size, and most of the previous statistical power surveys have covered broad research domains. The present study aimed to estimate the statistical power and to obtain realistic target effect sizes of depression research in Japan. We systematically reviewed 18 leading journals of psychiatry and psychology in Japan and identified 974 depression studies that were mentioned in 935 articles published between 1990 and 2006. In 392 studies, logistic regression analyses revealed that using clinical populations was independently associated with being a statistical power of <0.80 (odds ratio 5.9, 95% confidence interval 2.9-12.0) and of <0.50 (odds ratio 4.9, 95% confidence interval 2.3-10.5). Of the studies using clinical populations, 80% did not achieve a power of 0.80 or more, and 44% did not achieve a power of 0.50 or more to detect the medium population effect sizes. A predictive model for the proportion of variance explained was developed using a linear mixed-effects model. The model was then used to obtain realistic target effect sizes in defined study characteristics. In the face of a real difference or correlation in population, many depression researchers are less likely to give a valid result than simply tossing a coin. It is important to educate depression researchers in order to enable them to conduct an a priori power analysis. © 2011 The Authors. Psychiatry and Clinical Neurosciences © 2011 Japanese Society of Psychiatry and Neurology.

Personal birth preferences and actual mode of delivery outcomes of obstetricians and gynaecologists in South West England; with comparison to regional and national birth statistics.

PubMed

Lightly, Katie; Shaw, Elisabeth; Dailami, Narges; Bisson, Dina

2014-10-01

To determine personal birth preferences of obstetricians in various clinical scenarios, in particular elective caesarean section for maternal request. To determine actual rates of modes of deliveries amongst the same group. To compare the obstetrician's mode of delivery rates, to the general population. Following ethical approval, a piloted online survey link was sent via email to 242 current obstetricians and gynaecologists, (consultants and trainees) in South West England. Mode of delivery results were compared to regional and national population data, using Hospital Episode Statistics and subjected to statistical analysis. The response rate was 68%. 90% would hypothetically plan a vaginal delivery, 10% would consider a caesarean section in an otherwise uncomplicated primiparous pregnancy. Of the 94/165 (60%) respondents with children (201 children), mode of delivery for the first born child; normal vaginal delivery 48%, caesarean section 26.5% (elective 8.5%, emergency 18%), instrumental 24.5% and vaginal breech 1%. Only one chose an elective caesarean for maternal request. During 2006-2011 obstetricians have the same overall actual modes of birth as the population (p=0.9). Ten percent of obstetricians report they would consider requesting caesarean section for themselves/their partner, which is the lowest rate reported within UK studies. However only 1% actually had a caesarean solely for maternal choice. When compared to regional/national statistics obstetricians currently have modes of delivery that are not significantly different than the population and suggests that they choose non interventional delivery if possible. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Bibliometric Analysis on Cancer Population Science with Topic Modeling.

PubMed

Li, Ding-Cheng; Rastegar-Mojarad, Majid; Okamoto, Janet; Liu, Hongfang; Leichow, Scott

2015-01-01

Bibliometric analysis is a research method used in library and information science to evaluate research performance. It applies quantitative and statistical analyses to describe patterns observed in a set of publications and can help identify previous, current, and future research trends or focus. To better guide our institutional strategic plan in cancer population science, we conducted bibliometric analysis on publications of investigators currently funded by either Division of Cancer Preventions (DCP) or Division of Cancer Control and Population Science (DCCPS) at National Cancer Institute. We applied two topic modeling techniques: author topic modeling (AT) and dynamic topic modeling (DTM). Our initial results show that AT can address reasonably the issues related to investigators' research interests, research topic distributions and popularities. In compensation, DTM can address the evolving trend of each topic by displaying the proportion changes of key words, which is consistent with the changes of MeSH headings.

Individual and population pharmacokinetic compartment analysis: a graphic procedure for quantification of predictive performance.

PubMed

Eksborg, Staffan

2013-01-01

Pharmacokinetic studies are important for optimizing of drug dosing, but requires proper validation of the used pharmacokinetic procedures. However, simple and reliable statistical methods suitable for evaluation of the predictive performance of pharmacokinetic analysis are essentially lacking. The aim of the present study was to construct and evaluate a graphic procedure for quantification of predictive performance of individual and population pharmacokinetic compartment analysis. Original data from previously published pharmacokinetic compartment analyses after intravenous, oral, and epidural administration, and digitized data, obtained from published scatter plots of observed vs predicted drug concentrations from population pharmacokinetic studies using the NPEM algorithm and NONMEM computer program and Bayesian forecasting procedures, were used for estimating the predictive performance according to the proposed graphical method and by the method of Sheiner and Beal. The graphical plot proposed in the present paper proved to be a useful tool for evaluation of predictive performance of both individual and population compartment pharmacokinetic analysis. The proposed method is simple to use and gives valuable information concerning time- and concentration-dependent inaccuracies that might occur in individual and population pharmacokinetic compartment analysis. Predictive performance can be quantified by the fraction of concentration ratios within arbitrarily specified ranges, e.g. within the range 0.8-1.2.

Frequency distribution histograms for the rapid analysis of data

NASA Technical Reports Server (NTRS)

Burke, P. V.; Bullen, B. L.; Poff, K. L.

1988-01-01

The mean and standard error are good representations for the response of a population to an experimental parameter and are frequently used for this purpose. Frequency distribution histograms show, in addition, responses of individuals in the population. Both the statistics and a visual display of the distribution of the responses can be obtained easily using a microcomputer and available programs. The type of distribution shown by the histogram may suggest different mechanisms to be tested.

Analysis of forensically used autosomal short tandem repeat markers in Polish and neighboring populations.

PubMed

Soltyszewski, Ireneusz; Plocienniczak, Andrzej; Fabricius, Hans Ake; Kornienko, Igor; Vodolazhsky, Dmitrij; Parson, Walther; Hradil, Roman; Schmitter, Hermann; Ivanov, Pavel; Kuzniar, Piotr; Malyarchuk, Boris A; Grzybowski, Tomasz; Woźniak, Marcin; Henke, Jurgen; Henke, Lotte; Olkhovets, Sergiv; Voitenko, Vladimir; Lagus, Vita; Ficek, Andrej; Minárik, Gabriel; de Knijff, Peter; Rebała, Krzysztof; Wysocka, Joanna; Kapińska, Ewa; Cybulska, Lidia; Mikulich, Alexei I; Tsybovsky, Iosif S; Szczerkowska, Zofia; Krajewski, Paweł; Ploski, Rafał

2008-06-01

The purpose of this study was to evaluate the homogeneity of Polish populations with respect to STRs chosen as core markers of the Polish Forensic National DNA Intelligence Database, and to provide reference allele frequencies and to explore the genetic interrelationship between Poland and neighboring countries. The allele frequency distribution of 10 STRs included in the SGMplus kit was analyzed among 2176 unrelated individuals from 6 regional Polish populations and among 4321 individuals from Germany (three samples), Austria, The Netherlands, Sweden, Czech Republic, Slovakia, Belarus, Ukraine and the Russian Federation (six samples). The statistical approach consisted of AMOVA, calculation of pairwise Rst values and analysis by multidimensional scaling. We found homogeneity of present day Poland and consistent differences between Polish and German populations which contrasted with relative similarities between Russian and German populations. These discrepancies between genetic and geographic distances were confirmed by analysis of an independent data set on Y chromosome STRs. Migrations of Goths, Viking influences, German settlements in the region of Volga river and/or forced population resettlements and other events related to World War II are the historic events which might have caused these finding.

Meta-analysis of correlated traits via summary statistics from GWASs with an application in hypertension.

PubMed

Zhu, Xiaofeng; Feng, Tao; Tayo, Bamidele O; Liang, Jingjing; Young, J Hunter; Franceschini, Nora; Smith, Jennifer A; Yanek, Lisa R; Sun, Yan V; Edwards, Todd L; Chen, Wei; Nalls, Mike; Fox, Ervin; Sale, Michele; Bottinger, Erwin; Rotimi, Charles; Liu, Yongmei; McKnight, Barbara; Liu, Kiang; Arnett, Donna K; Chakravati, Aravinda; Cooper, Richard S; Redline, Susan

2015-01-08

Genome-wide association studies (GWASs) have identified many genetic variants underlying complex traits. Many detected genetic loci harbor variants that associate with multiple-even distinct-traits. Most current analysis approaches focus on single traits, even though the final results from multiple traits are evaluated together. Such approaches miss the opportunity to systemically integrate the phenome-wide data available for genetic association analysis. In this study, we propose a general approach that can integrate association evidence from summary statistics of multiple traits, either correlated, independent, continuous, or binary traits, which might come from the same or different studies. We allow for trait heterogeneity effects. Population structure and cryptic relatedness can also be controlled. Our simulations suggest that the proposed method has improved statistical power over single-trait analysis in most of the cases we studied. We applied our method to the Continental Origins and Genetic Epidemiology Network (COGENT) African ancestry samples for three blood pressure traits and identified four loci (CHIC2, HOXA-EVX1, IGFBP1/IGFBP3, and CDH17; p < 5.0 × 10(-8)) associated with hypertension-related traits that were missed by a single-trait analysis in the original report. Six additional loci with suggestive association evidence (p < 5.0 × 10(-7)) were also observed, including CACNA1D and WNT3. Our study strongly suggests that analyzing multiple phenotypes can improve statistical power and that such analysis can be executed with the summary statistics from GWASs. Our method also provides a way to study a cross phenotype (CP) association by using summary statistics from GWASs of multiple phenotypes. Copyright © 2015 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Statistics and bioinformatics in nutritional sciences: analysis of complex data in the era of systems biology⋆

PubMed Central

Fu, Wenjiang J.; Stromberg, Arnold J.; Viele, Kert; Carroll, Raymond J.; Wu, Guoyao

2009-01-01

Over the past two decades, there have been revolutionary developments in life science technologies characterized by high throughput, high efficiency, and rapid computation. Nutritionists now have the advanced methodologies for the analysis of DNA, RNA, protein, low-molecular-weight metabolites, as well as access to bioinformatics databases. Statistics, which can be defined as the process of making scientific inferences from data that contain variability, has historically played an integral role in advancing nutritional sciences. Currently, in the era of systems biology, statistics has become an increasingly important tool to quantitatively analyze information about biological macromolecules. This article describes general terms used in statistical analysis of large, complex experimental data. These terms include experimental design, power analysis, sample size calculation, and experimental errors (type I and II errors) for nutritional studies at population, tissue, cellular, and molecular levels. In addition, we highlighted various sources of experimental variations in studies involving microarray gene expression, real-time polymerase chain reaction, proteomics, and other bioinformatics technologies. Moreover, we provided guidelines for nutritionists and other biomedical scientists to plan and conduct studies and to analyze the complex data. Appropriate statistical analyses are expected to make an important contribution to solving major nutrition-associated problems in humans and animals (including obesity, diabetes, cardiovascular disease, cancer, ageing, and intrauterine fetal retardation). PMID:20233650

Robustness of S1 statistic with Hodges-Lehmann for skewed distributions

NASA Astrophysics Data System (ADS)

Ahad, Nor Aishah; Yahaya, Sharipah Soaad Syed; Yin, Lee Ping

2016-10-01

Analysis of variance (ANOVA) is a common use parametric method to test the differences in means for more than two groups when the populations are normally distributed. ANOVA is highly inefficient under the influence of non- normal and heteroscedastic settings. When the assumptions are violated, researchers are looking for alternative such as Kruskal-Wallis under nonparametric or robust method. This study focused on flexible method, S1 statistic for comparing groups using median as the location estimator. S1 statistic was modified by substituting the median with Hodges-Lehmann and the default scale estimator with the variance of Hodges-Lehmann and MADn to produce two different test statistics for comparing groups. Bootstrap method was used for testing the hypotheses since the sampling distributions of these modified S1 statistics are unknown. The performance of the proposed statistic in terms of Type I error was measured and compared against the original S1 statistic, ANOVA and Kruskal-Wallis. The propose procedures show improvement compared to the original statistic especially under extremely skewed distribution.

GWAMA: software for genome-wide association meta-analysis.

PubMed

Mägi, Reedik; Morris, Andrew P

2010-05-28

Despite the recent success of genome-wide association studies in identifying novel loci contributing effects to complex human traits, such as type 2 diabetes and obesity, much of the genetic component of variation in these phenotypes remains unexplained. One way to improving power to detect further novel loci is through meta-analysis of studies from the same population, increasing the sample size over any individual study. Although statistical software analysis packages incorporate routines for meta-analysis, they are ill equipped to meet the challenges of the scale and complexity of data generated in genome-wide association studies. We have developed flexible, open-source software for the meta-analysis of genome-wide association studies. The software incorporates a variety of error trapping facilities, and provides a range of meta-analysis summary statistics. The software is distributed with scripts that allow simple formatting of files containing the results of each association study and generate graphical summaries of genome-wide meta-analysis results. The GWAMA (Genome-Wide Association Meta-Analysis) software has been developed to perform meta-analysis of summary statistics generated from genome-wide association studies of dichotomous phenotypes or quantitative traits. Software with source files, documentation and example data files are freely available online at http://www.well.ox.ac.uk/GWAMA.

PRANAS: A New Platform for Retinal Analysis and Simulation.

PubMed

Cessac, Bruno; Kornprobst, Pierre; Kraria, Selim; Nasser, Hassan; Pamplona, Daniela; Portelli, Geoffrey; Viéville, Thierry

2017-01-01

The retina encodes visual scenes by trains of action potentials that are sent to the brain via the optic nerve. In this paper, we describe a new free access user-end software allowing to better understand this coding. It is called PRANAS (https://pranas.inria.fr), standing for Platform for Retinal ANalysis And Simulation. PRANAS targets neuroscientists and modelers by providing a unique set of retina-related tools. PRANAS integrates a retina simulator allowing large scale simulations while keeping a strong biological plausibility and a toolbox for the analysis of spike train population statistics. The statistical method (entropy maximization under constraints) takes into account both spatial and temporal correlations as constraints, allowing to analyze the effects of memory on statistics. PRANAS also integrates a tool computing and representing in 3D (time-space) receptive fields. All these tools are accessible through a friendly graphical user interface. The most CPU-costly of them have been implemented to run in parallel.

Population Analysis of Disabled Children by Departments in France

NASA Astrophysics Data System (ADS)

Meidatuzzahra, Diah; Kuswanto, Heri; Pech, Nicolas; Etchegaray, Amélie

2017-06-01

In this study, a statistical analysis is performed by model the variations of the disabled about 0-19 years old population among French departments. The aim is to classify the departments according to their profile determinants (socioeconomic and behavioural profiles). The analysis is focused on two types of methods: principal component analysis (PCA) and multiple correspondences factorial analysis (MCA) to review which one is the best methods for interpretation of the correlation between the determinants of disability (independent variable). The PCA is the best method for interpretation of the correlation between the determinants of disability (independent variable). The PCA reduces 14 determinants of disability to 4 axes, keeps 80% of total information, and classifies them into 7 classes. The MCA reduces the determinants to 3 axes, retains only 30% of information, and classifies them into 4 classes.

Linear regression analysis of Hospital Episode Statistics predicts a large increase in demand for elective hand surgery in England.

PubMed

Bebbington, Emily; Furniss, Dominic

2015-02-01

We integrated two factors, demographic population shifts and changes in prevalence of disease, to predict future trends in demand for hand surgery in England, to facilitate workforce planning. We analysed Hospital Episode Statistics data for Dupuytren's disease, carpal tunnel syndrome, cubital tunnel syndrome, and trigger finger from 1998 to 2011. Using linear regression, we estimated trends in both diagnosis and surgery until 2030. We integrated this regression with age specific population data from the Office for National Statistics in order to estimate how this will contribute to a change in workload over time. There has been a significant increase in both absolute numbers of diagnoses and surgery for all four conditions. Combined with future population data, we calculate that the total operative burden for these four conditions will increase from 87,582 in 2011 to 170,166 (95% confidence interval 144,517-195,353) in 2030. The prevalence of these diseases in the ageing population, and increasing prevalence of predisposing factors such as obesity and diabetes, may account for the predicted increase in workload. The most cost effective treatments must be sought, which requires high quality clinical trials. Our methodology can be applied to other sub-specialties to help anticipate the need for future service provision. Copyright © 2014 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

Experimental design and quantitative analysis of microbial community multiomics.

PubMed

Mallick, Himel; Ma, Siyuan; Franzosa, Eric A; Vatanen, Tommi; Morgan, Xochitl C; Huttenhower, Curtis

2017-11-30

Studies of the microbiome have become increasingly sophisticated, and multiple sequence-based, molecular methods as well as culture-based methods exist for population-scale microbiome profiles. To link the resulting host and microbial data types to human health, several experimental design considerations, data analysis challenges, and statistical epidemiological approaches must be addressed. Here, we survey current best practices for experimental design in microbiome molecular epidemiology, including technologies for generating, analyzing, and integrating microbiome multiomics data. We highlight studies that have identified molecular bioactives that influence human health, and we suggest steps for scaling translational microbiome research to high-throughput target discovery across large populations.

Random left censoring: a second look at bone lead concentration measurements

NASA Astrophysics Data System (ADS)

Popovic, M.; Nie, H.; Chettle, D. R.; McNeill, F. E.

2007-09-01

Bone lead concentrations measured in vivo by x-ray fluorescence (XRF) are subjected to left censoring due to limited precision of the technique at very low concentrations. In the analysis of bone lead measurements, inverse variance weighting (IVW) of measurements is commonly used to estimate the mean of a data set and its standard error. Student's t-test is used to compare the IVW means of two sets, testing the hypothesis that the two sets are from the same population. This analysis was undertaken to assess the adequacy of IVW in the analysis of bone lead measurements or to confirm the results of IVW using an independent approach. The rationale is provided for the use of methods of survival data analysis in the study of XRF bone lead measurements. The procedure is provided for bone lead data analysis using the Kaplan-Meier and Nelson-Aalen estimators. The methodology is also outlined for the rank tests that are used to determine whether two censored sets are from the same population. The methods are applied on six data sets acquired in epidemiological studies. The estimated parameters and test statistics were compared with the results of the IVW approach. It is concluded that the proposed methods of statistical analysis can provide valid inference about bone lead concentrations, but the computed parameters do not differ substantially from those derived by the more widely used method of IVW.

Colloquium: Statistical mechanics of money, wealth, and income

NASA Astrophysics Data System (ADS)

Yakovenko, Victor M.; Rosser, J. Barkley, Jr.

2009-10-01

This Colloquium reviews statistical models for money, wealth, and income distributions developed in the econophysics literature since the late 1990s. By analogy with the Boltzmann-Gibbs distribution of energy in physics, it is shown that the probability distribution of money is exponential for certain classes of models with interacting economic agents. Alternative scenarios are also reviewed. Data analysis of the empirical distributions of wealth and income reveals a two-class distribution. The majority of the population belongs to the lower class, characterized by the exponential (“thermal”) distribution, whereas a small fraction of the population in the upper class is characterized by the power-law (“superthermal”) distribution. The lower part is very stable, stationary in time, whereas the upper part is highly dynamical and out of equilibrium.

Analysis on the Climate Change Characteristics of Dianchi Lake Basin under the Background of Global Warming

NASA Astrophysics Data System (ADS)

Zhenyu, Yu; Luo, Yi; Yang, Kun; Qiongfei, Deng

2017-05-01

Based on the data published by the State Statistical Bureau and the weather station data, the annual mean temperature, wind speed, humidity, light duration and precipitation of Dianchi Lake in 1990 ~ 2014 were analysed. Combined with the population The results show that the climatic changes in Dianchi Lake basin are related to the climatic change in the past 25 years, and the correlation between these factors and the main climatic factors are analysed by linear regression, Mann-Kendall test, cumulative anomaly, R/S and Morlet wavelet analysis. Population, housing construction area growth and other aspects of the correlation trends and changes in the process, revealing the population expansion and housing construction area growth on the climate of the main factors of the cycle tendency of significant impact.

Ordinary chondrites - Multivariate statistical analysis of trace element contents

NASA Technical Reports Server (NTRS)

Lipschutz, Michael E.; Samuels, Stephen M.

1991-01-01

The contents of mobile trace elements (Co, Au, Sb, Ga, Se, Rb, Cs, Te, Bi, Ag, In, Tl, Zn, and Cd) in Antarctic and non-Antarctic populations of H4-6 and L4-6 chondrites, were compared using standard multivariate discriminant functions borrowed from linear discriminant analysis and logistic regression. A nonstandard randomization-simulation method was developed, making it possible to carry out probability assignments on a distribution-free basis. Compositional differences were found both between the Antarctic and non-Antarctic H4-6 chondrite populations and between two L4-6 chondrite populations. It is shown that, for various types of meteorites (in particular, for the H4-6 chondrites), the Antarctic/non-Antarctic compositional difference is due to preterrestrial differences in the genesis of their parent materials.

Cluster Analysis of Longidorus Species (Nematoda: Longidoridae), a New Approach in Species Identification

PubMed Central

Ye, Weimin; Robbins, R. T.

2004-01-01

Hierarchical cluster analysis based on female morphometric character means including body length, distance from vulva opening to anterior end, head width, odontostyle length, esophagus length, body width, tail length, and tail width were used to examine the morphometric relationships and create dendrograms for (i) 62 populations belonging to 9 Longidorus species from Arkansas, (ii) 137 published Longidorus species, and (iii) 137 published Longidorus species plus 86 populations of 16 Longidorus species from Arkansas and various other locations by using JMP 4.02 software (SAS Institute, Cary, NC). Cluster analysis dendograms visually illustrated the grouping and morphometric relationships of the species and populations. It provided a computerized statistical approach to assist by helping to identify and distinguish species, by indicating morphometric relationships among species, and by assisting with new species diagnosis. The preliminary species identification can be accomplished by running cluster analysis for unknown species together with the data matrix of known published Longidorus species. PMID:19262809

Cumulative trauma, hyperarousal, and suicidality in the general population: a path analysis.

PubMed

Briere, John; Godbout, Natacha; Dias, Colin

2015-01-01

Although trauma exposure and posttraumatic stress disorder (PTSD) both have been linked to suicidal thoughts and behavior, the underlying basis for this relationship is not clear. In a sample of 357 trauma-exposed individuals from the general population, younger participant age, cumulative trauma exposure, and all three Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, PTSD clusters (reexperiencing, avoidance, and hyperarousal) were correlated with clinical levels of suicidality. However, logistic regression analysis indicated that when all PTSD clusters were considered simultaneously, only hyperarousal continued to be predictive. A path analysis confirmed that posttraumatic hyperarousal (but not other components of PTSD) fully mediated the relationship between extent of trauma exposure and degree of suicidal thoughts and behaviors.

Machine learning for neuroimaging with scikit-learn.

PubMed

Abraham, Alexandre; Pedregosa, Fabian; Eickenberg, Michael; Gervais, Philippe; Mueller, Andreas; Kossaifi, Jean; Gramfort, Alexandre; Thirion, Bertrand; Varoquaux, Gaël

2014-01-01

Statistical machine learning methods are increasingly used for neuroimaging data analysis. Their main virtue is their ability to model high-dimensional datasets, e.g., multivariate analysis of activation images or resting-state time series. Supervised learning is typically used in decoding or encoding settings to relate brain images to behavioral or clinical observations, while unsupervised learning can uncover hidden structures in sets of images (e.g., resting state functional MRI) or find sub-populations in large cohorts. By considering different functional neuroimaging applications, we illustrate how scikit-learn, a Python machine learning library, can be used to perform some key analysis steps. Scikit-learn contains a very large set of statistical learning algorithms, both supervised and unsupervised, and its application to neuroimaging data provides a versatile tool to study the brain.

Machine learning for neuroimaging with scikit-learn

PubMed Central

Abraham, Alexandre; Pedregosa, Fabian; Eickenberg, Michael; Gervais, Philippe; Mueller, Andreas; Kossaifi, Jean; Gramfort, Alexandre; Thirion, Bertrand; Varoquaux, Gaël

2014-01-01

Statistical machine learning methods are increasingly used for neuroimaging data analysis. Their main virtue is their ability to model high-dimensional datasets, e.g., multivariate analysis of activation images or resting-state time series. Supervised learning is typically used in decoding or encoding settings to relate brain images to behavioral or clinical observations, while unsupervised learning can uncover hidden structures in sets of images (e.g., resting state functional MRI) or find sub-populations in large cohorts. By considering different functional neuroimaging applications, we illustrate how scikit-learn, a Python machine learning library, can be used to perform some key analysis steps. Scikit-learn contains a very large set of statistical learning algorithms, both supervised and unsupervised, and its application to neuroimaging data provides a versatile tool to study the brain. PMID:24600388

Delay, change and bifurcation of the immunofluorescence distribution attractors in health statuses diagnostics and in medical treatment

NASA Astrophysics Data System (ADS)

Galich, Nikolay E.; Filatov, Michael V.

2008-07-01

Communication contains the description of the immunology experiments and the experimental data treatment. New nonlinear methods of immunofluorescence statistical analysis of peripheral blood neutrophils have been developed. We used technology of respiratory burst reaction of DNA fluorescence in the neutrophils cells nuclei due to oxidative activity. The histograms of photon count statistics the radiant neutrophils populations' in flow cytometry experiments are considered. Distributions of the fluorescence flashes frequency as functions of the fluorescence intensity are analyzed. Statistic peculiarities of histograms set for healthy and unhealthy donors allow dividing all histograms on the three classes. The classification is based on three different types of smoothing and long-range scale averaged immunofluorescence distributions and their bifurcation. Heterogeneity peculiarities of long-range scale immunofluorescence distributions allow dividing all histograms on three groups. First histograms group belongs to healthy donors. Two other groups belong to donors with autoimmune and inflammatory diseases. Some of the illnesses are not diagnosed by standards biochemical methods. Medical standards and statistical data of the immunofluorescence histograms for identifications of health and illnesses are interconnected. Possibilities and alterations of immunofluorescence statistics in registration, diagnostics and monitoring of different diseases in various medical treatments have been demonstrated. Health or illness criteria are connected with statistics features of immunofluorescence histograms. Neutrophils populations' fluorescence presents the sensitive clear indicator of health status.

Genomic reconstruction of the history of extant populations of India reveals five distinct ancestral components and a complex structure

PubMed Central

Basu, Analabha; Sarkar-Roy, Neeta; Majumder, Partha P.

2016-01-01

India, occupying the center stage of Paleolithic and Neolithic migrations, has been underrepresented in genome-wide studies of variation. Systematic analysis of genome-wide data, using multiple robust statistical methods, on (i) 367 unrelated individuals drawn from 18 mainland and 2 island (Andaman and Nicobar Islands) populations selected to represent geographic, linguistic, and ethnic diversities, and (ii) individuals from populations represented in the Human Genome Diversity Panel (HGDP), reveal four major ancestries in mainland India. This contrasts with an earlier inference of two ancestries based on limited population sampling. A distinct ancestry of the populations of Andaman archipelago was identified and found to be coancestral to Oceanic populations. Analysis of ancestral haplotype blocks revealed that extant mainland populations (i) admixed widely irrespective of ancestry, although admixtures between populations was not always symmetric, and (ii) this practice was rapidly replaced by endogamy about 70 generations ago, among upper castes and Indo-European speakers predominantly. This estimated time coincides with the historical period of formulation and adoption of sociocultural norms restricting intermarriage in large social strata. A similar replacement observed among tribal populations was temporally less uniform. PMID:26811443

Variations of attractors and wavelet spectra of the immunofluorescence distributions for women in the pregnant period

NASA Astrophysics Data System (ADS)

Galich, Nikolay E.

2008-07-01

Communication contains the description of the immunology data treatment. New nonlinear methods of immunofluorescence statistical analysis of peripheral blood neutrophils have been developed. We used technology of respiratory burst reaction of DNA fluorescence in the neutrophils cells nuclei due to oxidative activity. The histograms of photon count statistics the radiant neutrophils populations' in flow cytometry experiments are considered. Distributions of the fluorescence flashes frequency as functions of the fluorescence intensity are analyzed. Statistic peculiarities of histograms set for women in the pregnant period allow dividing all histograms on the three classes. The classification is based on three different types of smoothing and long-range scale averaged immunofluorescence distributions, their bifurcation and wavelet spectra. Heterogeneity peculiarities of long-range scale immunofluorescence distributions and peculiarities of wavelet spectra allow dividing all histograms on three groups. First histograms group belongs to healthy donors. Two other groups belong to donors with autoimmune and inflammatory diseases. Some of the illnesses are not diagnosed by standards biochemical methods. Medical standards and statistical data of the immunofluorescence histograms for identifications of health and illnesses are interconnected. Peculiarities of immunofluorescence for women in pregnant period are classified. Health or illness criteria are connected with statistics features of immunofluorescence histograms. Neutrophils populations' fluorescence presents the sensitive clear indicator of health status.

Quantitative investigation of inappropriate regression model construction and the importance of medical statistics experts in observational medical research: a cross-sectional study.

PubMed

Nojima, Masanori; Tokunaga, Mutsumi; Nagamura, Fumitaka

2018-05-05

To investigate under what circumstances inappropriate use of 'multivariate analysis' is likely to occur and to identify the population that needs more support with medical statistics. The frequency of inappropriate regression model construction in multivariate analysis and related factors were investigated in observational medical research publications. The inappropriate algorithm of using only variables that were significant in univariate analysis was estimated to occur at 6.4% (95% CI 4.8% to 8.5%). This was observed in 1.1% of the publications with a medical statistics expert (hereinafter 'expert') as the first author, 3.5% if an expert was included as coauthor and in 12.2% if experts were not involved. In the publications where the number of cases was 50 or less and the study did not include experts, inappropriate algorithm usage was observed with a high proportion of 20.2%. The OR of the involvement of experts for this outcome was 0.28 (95% CI 0.15 to 0.53). A further, nation-level, analysis showed that the involvement of experts and the implementation of unfavourable multivariate analysis are associated at the nation-level analysis (R=-0.652). Based on the results of this study, the benefit of participation of medical statistics experts is obvious. Experts should be involved for proper confounding adjustment and interpretation of statistical models. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

A statistical analysis of the distribution of a larval nematode (Anisakis sp.) in the musculature of chum salmon (Oncorhynchus keta - Walbaum)

USGS Publications Warehouse

Novotny, A.J.

1960-01-01

The one factor which probably contributes the greatest effect on distributional patterns of Anisakis within chum salmon musculature is the total intensity of infection (or population density of Anisakis) in each fish.

An Analysis of Unemployment and Other Labor Market Indicators in 10 Countries.

ERIC Educational Resources Information Center

Moy, Joyanna

1988-01-01

Compares unemployment, employment, and related labor market statistics in the United States, Canada, Australia, Japan, France, Germany, Italy, the Netherlands, Sweden, and the United Kingdom. Introduces employment-to-population ratios by sex and discusses unemployment rates published by the Organization for Economic Cooperation and Development and…

42 CFR 81.11 - Use of uncertainty analysis in NIOSH-IREP.

Code of Federal Regulations, 2010 CFR

2010-10-01

... uncertainties in estimating: radiation dose incurred by the covered employee; the radiation dose-cancer relationship (statistical uncertainty in the specific cancer risk model); the extrapolation of risk (risk transfer) from the Japanese to the U.S. population; differences in the amount of cancer effect caused by...

42 CFR 81.11 - Use of uncertainty analysis in NIOSH-IREP.

Code of Federal Regulations, 2011 CFR

2011-10-01

... uncertainties in estimating: radiation dose incurred by the covered employee; the radiation dose-cancer relationship (statistical uncertainty in the specific cancer risk model); the extrapolation of risk (risk transfer) from the Japanese to the U.S. population; differences in the amount of cancer effect caused by...

Monitoring changes in exotic vegetation

Treesearch

Robert D. Sutter

1998-01-01

Ecological monitoring provides critical information for management decisions by measuring changes in managed and unmanaged populations, communities and ecological systems. It integrates ecology, goal and objective setting, sampling design, sampling methods, and statistical analysis. It is a topic that I, with a team of Nature Conservancy ecologists, teach in a six day...

42 CFR 81.11 - Use of uncertainty analysis in NIOSH-IREP.

Code of Federal Regulations, 2012 CFR

2012-10-01

... uncertainties in estimating: radiation dose incurred by the covered employee; the radiation dose-cancer relationship (statistical uncertainty in the specific cancer risk model); the extrapolation of risk (risk transfer) from the Japanese to the U.S. population; differences in the amount of cancer effect caused by...

42 CFR 81.11 - Use of uncertainty analysis in NIOSH-IREP.

Code of Federal Regulations, 2013 CFR

2013-10-01

... uncertainties in estimating: radiation dose incurred by the covered employee; the radiation dose-cancer relationship (statistical uncertainty in the specific cancer risk model); the extrapolation of risk (risk transfer) from the Japanese to the U.S. population; differences in the amount of cancer effect caused by...

42 CFR 81.11 - Use of uncertainty analysis in NIOSH-IREP.

Code of Federal Regulations, 2014 CFR

2014-10-01

... uncertainties in estimating: radiation dose incurred by the covered employee; the radiation dose-cancer relationship (statistical uncertainty in the specific cancer risk model); the extrapolation of risk (risk transfer) from the Japanese to the U.S. population; differences in the amount of cancer effect caused by...

Environmental Justice Assessment for Transportation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mills, G.S.; Neuhauser, K.S.

1999-04-05

Application of Executive Order 12898 to risk assessment of highway or rail transport of hazardous materials has proven difficult; the location and conditions affecting the propagation of a plume of hazardous material released in a potential accident are unknown, in general. Therefore, analyses have only been possible in geographically broad or approximate manner. The advent of geographic information systems and development of software enhancements at Sandia National Laboratories have made kilometer-by-kilometer analysis of populations tallied by U.S. Census Blocks along entire routes practicable. Tabulations of total, or racially/ethnically distinct, populations close to a route, its alternatives, or the broader surroundingmore » area, can then be compared and differences evaluated statistically. This paper presents methods of comparing populations and their racial/ethnic compositions using simple tabulations, histograms and Chi Squared tests for statistical significance of differences found. Two examples of these methods are presented: comparison of two routes and comparison of a route with its surroundings.« less

A statistical design for testing apomictic diversification through linkage analysis.

PubMed

Zeng, Yanru; Hou, Wei; Song, Shuang; Feng, Sisi; Shen, Lin; Xia, Guohua; Wu, Rongling

2014-03-01

The capacity of apomixis to generate maternal clones through seed reproduction has made it a useful characteristic for the fixation of heterosis in plant breeding. It has been observed that apomixis displays pronounced intra- and interspecific diversification, but the genetic mechanisms underlying this diversification remains elusive, obstructing the exploitation of this phenomenon in practical breeding programs. By capitalizing on molecular information in mapping populations, we describe and assess a statistical design that deploys linkage analysis to estimate and test the pattern and extent of apomictic differences at various levels from genotypes to species. The design is based on two reciprocal crosses between two individuals each chosen from a hermaphrodite or monoecious species. A multinomial distribution likelihood is constructed by combining marker information from two crosses. The EM algorithm is implemented to estimate the rate of apomixis and test its difference between two plant populations or species as the parents. The design is validated by computer simulation. A real data analysis of two reciprocal crosses between hickory (Carya cathayensis) and pecan (C. illinoensis) demonstrates the utilization and usefulness of the design in practice. The design provides a tool to address fundamental and applied questions related to the evolution and breeding of apomixis.

Statistical Analysis of Bending Rigidity Coefficient Determined Using Fluorescence-Based Flicker-Noise Spectroscopy.

PubMed

Doskocz, Joanna; Drabik, Dominik; Chodaczek, Grzegorz; Przybyło, Magdalena; Langner, Marek

2018-06-01

Bending rigidity coefficient describes propensity of a lipid bilayer to deform. In order to measure the parameter experimentally using flickering noise spectroscopy, the microscopic imaging is required, which necessitates the application of giant unilamellar vesicles (GUV) lipid bilayer model. The major difficulty associated with the application of the model is the statistical character of GUV population with respect to their size and the homogeneity of lipid bilayer composition, if a mixture of lipids is used. In the paper, the bending rigidity coefficient was measured using the fluorescence-enhanced flicker-noise spectroscopy. In the paper, the bending rigidity coefficient was determined for large populations of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine and 1,2-dioleoyl-sn-glycero-3-phosphocholine vesicles. The quantity of obtained experimental data allows to perform statistical analysis aiming at the identification of the distribution, which is the most appropriate for the calculation of the value of the membrane bending rigidity coefficient. It has been demonstrated that the bending rigidity coefficient is characterized by an asymmetrical distribution, which is well approximated with the gamma distribution. Since there are no biophysical reasons for that we propose to use the difference between normal and gamma fits as a measure of the homogeneity of vesicle population. In addition, the effect of a fluorescent label and types of instrumental setups on determined values has been tested. Obtained results show that the value of the bending rigidity coefficient does not depend on the type of a fluorescent label nor on the type of microscope used.

[Comparative analysis of STR and SNP polymorphism in the populations of sockeye salmon (Oncorhynchus nerka) from Eastern and Western Kamchatka].

PubMed

Khrustaleva, A M; Volkov, A A; Stoklitskaia, D S; Miuge, N S; Zelenina, D A

2010-11-01

Sockeye salmon samples from five largest lacustrine-riverine systems of Kamchatka Peninsula were tested for polymorphism at six microsatellite (STR) and five single nucleotide polymorphism (SNP) loci. Statistically significant genetic differentiation among local populations from this part of the species range examined was demonstrated. The data presented point to pronounced genetic divergence of the populations from two geographical regions, Eastern and Western Kamchatka. For sockeye salmon, the individual identification test accuracy was higher for microsatellites compared to similar number of SNP markers. Pooling of the STR and SNP allele frequency data sets provided the highest accuracy of the individual fish population assignment.

Genetic data for 26 autosomal STR markers from Brazilian population.

PubMed

Pereira, Tamiris Fátima Correia; Malaghini, Marcelo; Magalhães, João Carlos Maciel; Moura-Neto, Rodrigo; Sotomaior, Vanessa Santos

2018-01-19

The allelic frequency distributions and statistical forensic parameters of 26 mini short tandem repeat (mini-STR) loci in a sample of 1575 unrelated individuals from five different Brazilian regions were obtained. All the analyzed loci showed great diversity and were highly informative. The results were compared with those of the US Caucasian, African American, and Hispanic population studies. This study aimed to contribute to forensic analysis for human identification and inference of the evidential value in familial bond tests.

[Fenetic analysis of aboriginal and introduced sable (Martes zibellina) populations in Russia].

PubMed

Monakhov, V G

2001-09-01

Using standard and mulivariate statistic methods, an epigenetic character--foramina in fossa condyloidei inferior, FFCI--was studied in sable populations. This character was shown to be most frequent in southeastern populations of the species (Primorye and the Baikal region) while its distribution in the remaining part of the range was polyclinal. The expression of FFCI was directly associated with coat color and longitude, and inversely associated with skull size. This trend was broken by some western populations formed in the 1950s by introduction, which exhibited stable morphological differences with adjacent aboriginal sable populations. Most populations of the species exhibit differences in the manifestation of the character. Frequency of the FFCI manifestation can be used as an additional population characteristic, an associative diagnostic character that shows high discriminating capability in detecting phenogenetic relationships of intraspecific groups.

Matrix population models from 20 studies of perennial plant populations

USGS Publications Warehouse

Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.

2012-01-01

Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the "Testing Matrix Models" working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.

Matrix population models from 20 studies of perennial plant populations

USGS Publications Warehouse

Ellis, Martha M.; Williams, Jennifer L.; Lesica, Peter; Bell, Timothy J.; Bierzychudek, Paulette; Bowles, Marlin; Crone, Elizabeth E.; Doak, Daniel F.; Ehrlen, Johan; Ellis-Adam, Albertine; McEachern, Kathryn; Ganesan, Rengaian; Latham, Penelope; Luijten, Sheila; Kaye, Thomas N.; Knight, Tiffany M.; Menges, Eric S.; Morris, William F.; den Nijs, Hans; Oostermeijer, Gerard; Quintana-Ascencio, Pedro F.; Shelly, J. Stephen; Stanley, Amanda; Thorpe, Andrea; Tamara, Ticktin; Valverde, Teresa; Weekley, Carl W.

2012-01-01

Demographic transition matrices are one of the most commonly applied population models for both basic and applied ecological research. The relatively simple framework of these models and simple, easily interpretable summary statistics they produce have prompted the wide use of these models across an exceptionally broad range of taxa. Here, we provide annual transition matrices and observed stage structures/population sizes for 20 perennial plant species which have been the focal species for long-term demographic monitoring. These data were assembled as part of the 'Testing Matrix Models' working group through the National Center for Ecological Analysis and Synthesis (NCEAS). In sum, these data represent 82 populations with >460 total population-years of data. It is our hope that making these data available will help promote and improve our ability to monitor and understand plant population dynamics.

Heterogeneity of Metazoan Cells and Beyond: To Integrative Analysis of Cellular Populations at Single-Cell Level.

PubMed

Barteneva, Natasha S; Vorobjev, Ivan A

2018-01-01

In this paper, we review some of the recent advances in cellular heterogeneity and single-cell analysis methods. In modern research of cellular heterogeneity, there are four major approaches: analysis of pooled samples, single-cell analysis, high-throughput single-cell analysis, and lately integrated analysis of cellular population at a single-cell level. Recently developed high-throughput single-cell genetic analysis methods such as RNA-Seq require purification step and destruction of an analyzed cell often are providing a snapshot of the investigated cell without spatiotemporal context. Correlative analysis of multiparameter morphological, functional, and molecular information is important for differentiation of more uniform groups in the spectrum of different cell types. Simplified distributions (histograms and 2D plots) can underrepresent biologically significant subpopulations. Future directions may include the development of nondestructive methods for dissecting molecular events in intact cells, simultaneous correlative cellular analysis of phenotypic and molecular features by hybrid technologies such as imaging flow cytometry, and further progress in supervised and non-supervised statistical analysis algorithms.

Identity-by-descent analyses for measuring population dynamics and selection in recombining pathogens.

PubMed

Henden, Lyndal; Lee, Stuart; Mueller, Ivo; Barry, Alyssa; Bahlo, Melanie

2018-05-01

Identification of genomic regions that are identical by descent (IBD) has proven useful for human genetic studies where analyses have led to the discovery of familial relatedness and fine-mapping of disease critical regions. Unfortunately however, IBD analyses have been underutilized in analysis of other organisms, including human pathogens. This is in part due to the lack of statistical methodologies for non-diploid genomes in addition to the added complexity of multiclonal infections. As such, we have developed an IBD methodology, called isoRelate, for analysis of haploid recombining microorganisms in the presence of multiclonal infections. Using the inferred IBD status at genomic locations, we have also developed a novel statistic for identifying loci under positive selection and propose relatedness networks as a means of exploring shared haplotypes within populations. We evaluate the performance of our methodologies for detecting IBD and selection, including comparisons with existing tools, then perform an exploratory analysis of whole genome sequencing data from a global Plasmodium falciparum dataset of more than 2500 genomes. This analysis identifies Southeast Asia as having many highly related isolates, possibly as a result of both reduced transmission from intensified control efforts and population bottlenecks following the emergence of antimalarial drug resistance. Many signals of selection are also identified, most of which overlap genes that are known to be associated with drug resistance, in addition to two novel signals observed in multiple countries that have yet to be explored in detail. Additionally, we investigate relatedness networks over the selected loci and determine that one of these sweeps has spread between continents while the other has arisen independently in different countries. IBD analysis of microorganisms using isoRelate can be used for exploring population structure, positive selection and haplotype distributions, and will be a valuable tool for monitoring disease control and elimination efforts of many diseases.

CAN'T MISS--conquer any number task by making important statistics simple. Part 2. Probability, populations, samples, and normal distributions.

PubMed

Hansen, John P

2003-01-01

Healthcare quality improvement professionals need to understand and use inferential statistics to interpret sample data from their organizations. In quality improvement and healthcare research studies all the data from a population often are not available, so investigators take samples and make inferences about the population by using inferential statistics. This three-part series will give readers an understanding of the concepts of inferential statistics as well as the specific tools for calculating confidence intervals for samples of data. This article, Part 2, describes probability, populations, and samples. The uses of descriptive and inferential statistics are outlined. The article also discusses the properties and probability of normal distributions, including the standard normal distribution.

Rapid identification of apolipoprotein E genotypes by high-resolution melting analysis in Chinese Han and African Fang populations.

PubMed

Zhan, Xiu-Hui; Zha, Guang-Cai; Jiao, Ji-Wei; Yang, Li-Ye; Zhan, Xiao-Fen; Chen, Jiang-Tao; Xie, Dong-DE; Eyi, Urbano Monsuy; Matesa, Rocio Apicante; Obono, Maximo Miko Ondo; Ehapo, Carlos Sala; Wei, Er-Jia; Zheng, Yu-Zhong; Yang, Hui; Lin, Min

2015-02-01

Apolipoprotein E (APOE) gene polymorphism can affect APOE gene transcription, serum lipid levels and repair of tissue damage, which could place individuals at serious risk of cardiovascular disease or certain infectious diseases. Recently, high-resolution melting (HRM) analysis was reported to be a simple, inexpensive, accurate and sensitive method for the genotyping or/and scanning of rare mutations. For this reason, an HRM analysis was used in the present study for APOE genotyping in the Southern Chinese Han and African Fang populations. A total of 100 healthy Southern Chinese Han and 175 healthy African Fang individuals attended the study. Polymerase chain reaction-DNA sequencing was used as a reference method for the genotyping of these samples. The six APOE genotypes could all be rapidly and efficiently identified by HRM analysis, and 100% concordance was found between the HRM analysis and the reference method. The allele frequencies of APOE in the Southern Chinese Han population were 7.0, 87.5 and 5.5% for ɛ2, ɛ3 and ɛ4, respectively. In the African Fang population, the allele frequencies of APOE were 24.3, 65.7 and 10.0% for ɛ2, ɛ3 and ɛ4, respectively. A statistically significant difference was found between the allele frequencies between the populations (P<0.05). In conclusion, the present study revealed the molecular characterization of APOE gene polymorphism in the Han population from the Chaozhou region of Southern China and the Fang population from Equatorial Guinea. The findings of the study indicated that HRM analysis could be used as an accurate and sensitive method for the rapid screening and identification of APOE genotypes in prospective clinical and population genetic analyses.

Assessment of diversity among populations of Rauvolfia serpentina Benth. Ex. Kurtz. from Southern Western Ghats of India, based on chemical profiling, horticultural traits and RAPD analysis.

PubMed

Nair, Vadakkemuriyil Divya; Raj, Rajan Pillai Dinesh; Panneerselvam, Rajaram; Gopi, Ragupathi

2014-01-01

Genetic, morphological and chemical variations of ten natural populations of Rauvolfia serpentina Benth. Ex. Kurtz. from Southern Western Ghats of India were assessed using RAPD markers reserpine content and morphological traits. An estimate of genetic diversity and differentiation between genotypes of breeding germplasm is of key importance for its improvement. Populations were collected from different geographical regions. Data obtained through three different methods were compared and the correlation among them was estimated. Statistical analysis showed significant differences for all horticultural characteristics among the accessions suggesting that selection for relevant characteristics could be possible. Variation in the content of Reserpine ranges from 0.192 g/100 g (population from Tusharagiri) to 1.312 g/100 g (population from Aryankavu). A high diversity within population and high genetic differentiation among them based on RAPDs were revealed caused both by habitat fragmentation of the low size of most populations and the low level of gene flow among them. The UPGMA dendrogram and PCA analysis based on reserpine content yielded higher separation among populations indicated specific adaptation of populations into clusters each of them including populations closed to their geographical origin. Genetic, chemical and morphological data were correlated based on Mantel test. Given the high differentiation among populations conservation strategies should take into account genetic diversity and chemical variation levels in relation to bioclimatic and geographic location of populations. Our results also indicate that RAPD approach along with horticultural analysis seemed to be best suited for assessing with high accuracy the genetic relationships among distinct R. serpentina accessions. © 2013.

Enhanced statistical tests for GWAS in admixed populations: assessment using African Americans from CARe and a Breast Cancer Consortium.

PubMed

Pasaniuc, Bogdan; Zaitlen, Noah; Lettre, Guillaume; Chen, Gary K; Tandon, Arti; Kao, W H Linda; Ruczinski, Ingo; Fornage, Myriam; Siscovick, David S; Zhu, Xiaofeng; Larkin, Emma; Lange, Leslie A; Cupples, L Adrienne; Yang, Qiong; Akylbekova, Ermeg L; Musani, Solomon K; Divers, Jasmin; Mychaleckyj, Joe; Li, Mingyao; Papanicolaou, George J; Millikan, Robert C; Ambrosone, Christine B; John, Esther M; Bernstein, Leslie; Zheng, Wei; Hu, Jennifer J; Ziegler, Regina G; Nyante, Sarah J; Bandera, Elisa V; Ingles, Sue A; Press, Michael F; Chanock, Stephen J; Deming, Sandra L; Rodriguez-Gil, Jorge L; Palmer, Cameron D; Buxbaum, Sarah; Ekunwe, Lynette; Hirschhorn, Joel N; Henderson, Brian E; Myers, Simon; Haiman, Christopher A; Reich, David; Patterson, Nick; Wilson, James G; Price, Alkes L

2011-04-01

While genome-wide association studies (GWAS) have primarily examined populations of European ancestry, more recent studies often involve additional populations, including admixed populations such as African Americans and Latinos. In admixed populations, linkage disequilibrium (LD) exists both at a fine scale in ancestral populations and at a coarse scale (admixture-LD) due to chromosomal segments of distinct ancestry. Disease association statistics in admixed populations have previously considered SNP association (LD mapping) or admixture association (mapping by admixture-LD), but not both. Here, we introduce a new statistical framework for combining SNP and admixture association in case-control studies, as well as methods for local ancestry-aware imputation. We illustrate the gain in statistical power achieved by these methods by analyzing data of 6,209 unrelated African Americans from the CARe project genotyped on the Affymetrix 6.0 chip, in conjunction with both simulated and real phenotypes, as well as by analyzing the FGFR2 locus using breast cancer GWAS data from 5,761 African-American women. We show that, at typed SNPs, our method yields an 8% increase in statistical power for finding disease risk loci compared to the power achieved by standard methods in case-control studies. At imputed SNPs, we observe an 11% increase in statistical power for mapping disease loci when our local ancestry-aware imputation framework and the new scoring statistic are jointly employed. Finally, we show that our method increases statistical power in regions harboring the causal SNP in the case when the causal SNP is untyped and cannot be imputed. Our methods and our publicly available software are broadly applicable to GWAS in admixed populations.

Allelic Prevalence of ABO Blood Group Genes in Iranian Azari Population

PubMed Central

Nojavan, Mohammad; Shamsasenjan, Karrim; Movassaghpour, Ali Akbar; Akbarzadehlaleh, Parvin; Torabi, Seyd Esmail; Ghojazadeh, Morteza

2012-01-01

Introduction ABO blood group system is the most important blood group in transfusion and has been widely used in population studies. Several molecular techniques for ABO allele’s detection are widely used for distinguishing various alleles of glycosyl transferase locus on chromosome 9. Methods 744 randomly selected samples from Azari donors of East Azerbaijan province (Iran) were examined using well-adjusted multiplex allele- specific PCR ABO genotyping technique. Results The results were consistent for all individuals. The ABO blood group genotype of 744 healthy Azari blood donors was: 25.8% AA/AO (2), 7.6% AO (1), 1.6% BB, 11.3% B0 (1), 10% AB, 9.3% 0(1)0(1) and 15.3%0(1)0(2). The highest genotype frequency belonged to O01/O02 genotype (15.3%) and the lowest frequency belonged to A101/A102 genotype (0.4%). Conclusions: The frequencies of ABO alleles didn’t show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05). Conclusions The frequencies of ABO alleles didn’t show significant differences between East Azerbaijan province population and that of other areas of the country. Meanwhile, statistical analysis of frequencies of A and B alleles between East Azerbaijan province population and neighbor countries showed significant differences whereas the frequency of allele O between them did not show significant difference (P>0.05). PMID:23678461

Statistical detection of patterns in unidimensional distributions by continuous wavelet transforms

NASA Astrophysics Data System (ADS)

Baluev, R. V.

2018-04-01

Objective detection of specific patterns in statistical distributions, like groupings or gaps or abrupt transitions between different subsets, is a task with a rich range of applications in astronomy: Milky Way stellar population analysis, investigations of the exoplanets diversity, Solar System minor bodies statistics, extragalactic studies, etc. We adapt the powerful technique of the wavelet transforms to this generalized task, making a strong emphasis on the assessment of the patterns detection significance. Among other things, our method also involves optimal minimum-noise wavelets and minimum-noise reconstruction of the distribution density function. Based on this development, we construct a self-closed algorithmic pipeline aimed to process statistical samples. It is currently applicable to single-dimensional distributions only, but it is flexible enough to undergo further generalizations and development.

Clinical study of the Erlanger silver catheter--data management and biometry.

PubMed

Martus, P; Geis, C; Lugauer, S; Böswald, M; Guggenbichler, J P

1999-01-01

The clinical evaluation of venous catheters for catheter-induced infections must conform to a strict biometric methodology. The statistical planning of the study (target population, design, degree of blinding), data management (database design, definition of variables, coding), quality assurance (data inspection at several levels) and the biometric evaluation of the Erlanger silver catheter project are described. The three-step data flow included: 1) primary data from the hospital, 2) relational database, 3) files accessible for statistical evaluation. Two different statistical models were compared: analyzing the first catheter only of a patient in the analysis (independent data) and analyzing several catheters from the same patient (dependent data) by means of the generalized estimating equations (GEE) method. The main result of the study was based on the comparison of both statistical models.

10 CFR Appendix A to Subpart A of... - Metropolitan Statistical Areas/Consolidated Metropolitan Statistical Areas With 1980 Populations...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 3 2010-01-01 2010-01-01 false Metropolitan Statistical Areas/Consolidated Metropolitan Statistical Areas With 1980 Populations of 250,000 or more A Appendix A to Subpart A of Part 490 Energy..., Subpt. A, App. A Appendix A to Subpart A of Part 490—Metropolitan Statistical Areas/Consolidated...

Reliability of third molar development for age estimation in Gujarati population: A comparative study.

PubMed

Gandhi, Neha; Jain, Sandeep; Kumar, Manish; Rupakar, Pratik; Choyal, Kanaram; Prajapati, Seema

2015-01-01

Age assessment may be a crucial step in postmortem profiling leading to confirmative identification. In children, Demirjian's method based on eight developmental stages was developed to determine maturity scores as a function of age and polynomial functions to determine age as a function of score. Of this study was to evaluate the reliability of age estimation using Demirjian's eight teeth method following the French maturity scores and Indian-specific formula from developmental stages of third molar with the help of orthopantomograms using the Demirjian method. Dental panoramic tomograms from 30 subjects each of known chronological age and sex were collected and were evaluated according to Demirjian's criteria. Age calculations were performed using Demirjian's formula and Indian formula. Statistical analysis used was Chi-square test and ANOVA test and the P values obtained were statistically significant. There was an average underestimation of age with both Indian and Demirjian's formulas. The mean absolute error was lower using Indian formula hence it can be applied for age estimation in present Gujarati population. Also, females were ahead of achieving dental maturity than males thus completion of dental development is attained earlier in females. Greater accuracy can be obtained if population-specific formulas considering the ethnic and environmental variation are derived performing the regression analysis.

An Analysis Pipeline with Statistical and Visualization-Guided Knowledge Discovery for Michigan-Style Learning Classifier Systems

PubMed Central

Urbanowicz, Ryan J.; Granizo-Mackenzie, Ambrose; Moore, Jason H.

2014-01-01

Michigan-style learning classifier systems (M-LCSs) represent an adaptive and powerful class of evolutionary algorithms which distribute the learned solution over a sizable population of rules. However their application to complex real world data mining problems, such as genetic association studies, has been limited. Traditional knowledge discovery strategies for M-LCS rule populations involve sorting and manual rule inspection. While this approach may be sufficient for simpler problems, the confounding influence of noise and the need to discriminate between predictive and non-predictive attributes calls for additional strategies. Additionally, tests of significance must be adapted to M-LCS analyses in order to make them a viable option within fields that require such analyses to assess confidence. In this work we introduce an M-LCS analysis pipeline that combines uniquely applied visualizations with objective statistical evaluation for the identification of predictive attributes, and reliable rule generalizations in noisy single-step data mining problems. This work considers an alternative paradigm for knowledge discovery in M-LCSs, shifting the focus from individual rules to a global, population-wide perspective. We demonstrate the efficacy of this pipeline applied to the identification of epistasis (i.e., attribute interaction) and heterogeneity in noisy simulated genetic association data. PMID:25431544

Prevalence of High Blood Pressure, Heart Disease, Thalassemia, Sickle-Cell Anemia, and Iron-Deficiency Anemia among the UAE Adolescent Population

PubMed Central

Barakat-Haddad, Caroline

2013-01-01

This study examined the prevalence of high blood pressure, heart disease, and medical diagnoses in relation to blood disorders, among 6,329 adolescent students (age 15 to 18 years) who reside in the United Arab Emirates (UAE). Findings indicated that the overall prevalence of high blood pressure and heart disease was 1.8% and 1.3%, respectively. Overall, the prevalence for thalassemia, sickle-cell anemia, and iron-deficiency anemia was 0.9%, 1.6%, and 5%, respectively. Bivariate analysis revealed statistically significant differences in the prevalence of high blood pressure among the local and expatriate adolescent population in the Emirate of Sharjah. Similarly, statistically significant differences in the prevalence of iron-deficiency anemia were observed among the local and expatriate population in Abu Dhabi city, the western region of Abu Dhabi, and Al-Ain. Multivariate analysis revealed the following significant predictors of high blood pressure: residing in proximity to industry, nonconventional substance abuse, and age when smoking or exposure to smoking began. Ethnicity was a significant predictor of heart disease, thalassemia, sickle-cell anemia, and iron-deficiency anemia. In addition, predictors of thalassemia included gender (female) and participating in physical activity. Participants diagnosed with sickle-cell anemia and iron-deficiency anemia were more likely to experience different physical activities. PMID:23606864

Food security and the nutritional status of children in foster care: new horizons in the protection of a fragile population.

PubMed

Ferrara, Pietro; Scancarello, Marta; Khazrai, Yeganeh M; Romani, Lorenza; Cutrona, Costanza; DE Gara, Laura; Bona, Gianni

2016-10-12

The nutritional status of foster children, the quality of daily menus in group homes and the Food Security inside these organizations have been poorly studied and this study means to investigate them. A sample of 125 children, ranging in age from 0-17 years, among seven group homes (group A) was compared with 121 children of the general population we (group B). To evaluate nutritional status, BMI percentiles were used. Mean percentiles of both groups were compared through statistical analysis. Both nutritional and caloric daily distributions in each organization were obtained using the 24-hour recall method. A specific questionnaire was administered to evaluate Food Security. From the analysis of mean BMI-for-age (or height-for-length) percentiles, did not observe statistically significant differences between group A and group B. The average daily nutrient and calorie distribution in group homes proves to be nearly optimal with the exception of a slight excess in proteins and a slight deficiency in PUFAs. Moreover, a low intake of iron and calcium was revealed. All organizations obtained a "High Food Security" profile. Nutritional conditions of foster children are no worse than that of children of the general population. Foster care provides the necessary conditions to support their growth.

Data on education: from population statistics to epidemiological research.

PubMed

Pallesen, Palle Bo; Tverborgvik, Torill; Rasmussen, Hanna Barbara; Lynge, Elsebeth

2010-03-01

Level of education is in many fields of research used as an indicator of social status. Using Statistics Denmark's register for education and employment of the population, we examined highest completed education with a birth-cohort perspective focusing on people born between 1930 and 1974. Irregularities in the educational data were found for both men and women born from 1951 to 1957. For the birth cohorts born from 1951 to 1954, a sudden increase in the proportion of persons with basic school education only was seen, and a following decrease in this proportion was seen for the birth cohorts born from 1955 to 1957. For the same birth cohorts, a reverse curve was found for the proportion with vocational training as highest completed education. Using proportion of women with at least one child at the age of 30, our analysis illustrated that spurious patterns may emerge when other social phenomena are analysed by partly misclassified educational groups. Our findings showed that register data are not always to be taken at face value and that thorough analysis may unravel unexpected irregularities. Although such data errors may be remedied in analyses of population trends by use of extrapolated values, solutions are less obvious in epidemiological research using individual level data.

Assessing privacy risks in population health publications using a checklist-based approach.

PubMed

O'Keefe, Christine M; Ickowicz, Adrien; Churches, Tim; Westcott, Mark; O'Sullivan, Maree; Khan, Atikur

2017-11-10

Recent growth in the number of population health researchers accessing detailed datasets, either on their own computers or through virtual data centers, has the potential to increase privacy risks. In response, a checklist for identifying and reducing privacy risks in population health analysis outputs has been proposed for use by researchers themselves. In this study we explore the usability and reliability of such an approach by investigating whether different users identify the same privacy risks on applying the checklist to a sample of publications. The checklist was applied to a sample of 100 academic population health publications distributed among 5 readers. Cohen's κ was used to measure interrater agreement. Of the 566 instances of statistical output types found in the 100 publications, the most frequently occurring were counts, summary statistics, plots, and model outputs. Application of the checklist identified 128 outputs (22.6%) with potential privacy concerns. Most of these were associated with the reporting of small counts. Among these identified outputs, the readers found no substantial actual privacy concerns when context was taken into account. Interrater agreement for identifying potential privacy concerns was generally good. This study has demonstrated that a checklist can be a reliable tool to assist researchers with anonymizing analysis outputs in population health research. This further suggests that such an approach may have the potential to be developed into a broadly applicable standard providing consistent confidentiality protection across multiple analyses of the same data. © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Population activity structure of excitatory and inhibitory neurons

PubMed Central

Doiron, Brent

2017-01-01

Many studies use population analysis approaches, such as dimensionality reduction, to characterize the activity of large groups of neurons. To date, these methods have treated each neuron equally, without taking into account whether neurons are excitatory or inhibitory. We studied population activity structure as a function of neuron type by applying factor analysis to spontaneous activity from spiking networks with balanced excitation and inhibition. Throughout the study, we characterized population activity structure by measuring its dimensionality and the percentage of overall activity variance that is shared among neurons. First, by sampling only excitatory or only inhibitory neurons, we found that the activity structures of these two populations in balanced networks are measurably different. We also found that the population activity structure is dependent on the ratio of excitatory to inhibitory neurons sampled. Finally we classified neurons from extracellular recordings in the primary visual cortex of anesthetized macaques as putative excitatory or inhibitory using waveform classification, and found similarities with the neuron type-specific population activity structure of a balanced network with excitatory clustering. These results imply that knowledge of neuron type is important, and allows for stronger statistical tests, when interpreting population activity structure. PMID:28817581

Admixture, Population Structure, and F-Statistics.

PubMed

Peter, Benjamin M

2016-04-01

Many questions about human genetic history can be addressed by examining the patterns of shared genetic variation between sets of populations. A useful methodological framework for this purpose isF-statistics that measure shared genetic drift between sets of two, three, and four populations and can be used to test simple and complex hypotheses about admixture between populations. This article provides context from phylogenetic and population genetic theory. I review how F-statistics can be interpreted as branch lengths or paths and derive new interpretations, using coalescent theory. I further show that the admixture tests can be interpreted as testing general properties of phylogenies, allowing extension of some ideas applications to arbitrary phylogenetic trees. The new results are used to investigate the behavior of the statistics under different models of population structure and show how population substructure complicates inference. The results lead to simplified estimators in many cases, and I recommend to replace F3 with the average number of pairwise differences for estimating population divergence. Copyright © 2016 by the Genetics Society of America.

Long-term survival following open repair of ruptured abdominal aortic aneurysm.

PubMed

Englund, Raymond; Katib, Nedal

2017-05-01

Long-term results for patients being managed for ruptured compared to elective abdominal aortic aneurysms (AAA) are unclear. We hypothesize that patients who survive 30 days or more following repair of ruptured AAA (RAAA) performed by open technique have a life expectancy no different to those patients surviving 30 days or more following elective AAA repair, or compared to a general age-matched population. Between 1987 and December 2014, 620 consecutive patients were treated by the principal author for aortic aneurysmal disease. Two subgroups were selected from this population, elective open abdominal repair (215) and RAAA open repair (105). Comparable age-matched life curves with the general population were used from the Australian Bureau of Statistics for each patient according to gender, age and date of presentation. Statistical comparison was by Kaplan-Meier survival analysis. Both the open and RAAA groups were well matched for age and sex. There was no statistical difference between RAAA survival and an age-matched population P = 0.23, or was there any difference between open repair and an age-matched population, P = 0.1. Survival curves for RAAA and open repair were similar, P = 0.98. For elective open repair 1-, 5-, 10-, 15- and 20-year survival was 93.6, 71.2, 40, 17 and 2% respectively. Corresponding results for RAAA were 92.5, 74, 36.7, 13.5 and 5% respectively. Open AAA repair for RAAA or elective aneurysm treatment restores predicted life expectancy for those patients surviving 30 days or more and is therefore a durable method of treatment for this condition. © 2016 Royal Australasian College of Surgeons.

Functional status predicts acute care readmission in the traumatic spinal cord injury population.

PubMed

Huang, Donna; Slocum, Chloe; Silver, Julie K; Morgan, James W; Goldstein, Richard; Zafonte, Ross; Schneider, Jeffrey C

2018-03-29

Context/objective Acute care readmission has been identified as an important marker of healthcare quality. Most previous models assessing risk prediction of readmission incorporate variables for medical comorbidity. We hypothesized that functional status is a more robust predictor of readmission in the spinal cord injury population than medical comorbidities. Design Retrospective cross-sectional analysis. Setting Inpatient rehabilitation facilities, Uniform Data System for Medical Rehabilitation data from 2002 to 2012 Participants traumatic spinal cord injury patients. Outcome measures A logistic regression model for predicting acute care readmission based on demographic variables and functional status (Functional Model) was compared with models incorporating demographics, functional status, and medical comorbidities (Functional-Plus) or models including demographics and medical comorbidities (Demographic-Comorbidity). The primary outcomes were 3- and 30-day readmission, and the primary measure of model performance was the c-statistic. Results There were a total of 68,395 patients with 1,469 (2.15%) readmitted at 3 days and 7,081 (10.35%) readmitted at 30 days. The c-statistics for the Functional Model were 0.703 and 0.654 for 3 and 30 days. The Functional Model outperformed Demographic-Comorbidity models at 3 days (c-statistic difference: 0.066-0.096) and outperformed two of the three Demographic-Comorbidity models at 30 days (c-statistic difference: 0.029-0.056). The Functional-Plus models exhibited negligible improvements (0.002-0.010) in model performance compared to the Functional models. Conclusion Readmissions are used as a marker of hospital performance. Function-based readmission models in the spinal cord injury population outperform models incorporating medical comorbidities. Readmission risk models for this population would benefit from the inclusion of functional status.

Laser fluorescence fluctuation excesses in molecular immunology experiments

NASA Astrophysics Data System (ADS)

Galich, N. E.; Filatov, M. V.

2007-04-01

A novel approach to statistical analysis of flow cytometry fluorescence data have been developed and applied for population analysis of blood neutrophils stained with hydroethidine during respiratory burst reaction. The staining based on intracellular oxidation hydroethidine to ethidium bromide, which intercalate into cell DNA. Fluorescence of the resultant product serves as a measure of the neutrophil ability to generate superoxide radicals after induction respiratory burst reaction by phorbol myristate acetate (PMA). It was demonstrated that polymorphonuclear leukocytes of persons with inflammatory diseases showed a considerably changed response. Cytofluorometric histograms obtained have unique information about condition of neutrophil population what might to allow a determination of the pathology processes type connecting with such inflammation. A novel approach to histogram analysis is based on analysis of high-momentum dynamic of distribution. The features of fluctuation excesses of distribution have unique information about disease under consideration.

Validation of a physical anthropology methodology using mandibles for gender estimation in a Brazilian population

PubMed Central

CARVALHO, Suzana Papile Maciel; BRITO, Liz Magalhães; de PAIVA, Luiz Airton Saavedra; BICUDO, Lucilene Arilho Ribeiro; CROSATO, Edgard Michel; de OLIVEIRA, Rogério Nogueira

2013-01-01

Validation studies of physical anthropology methods in the different population groups are extremely important, especially in cases in which the population variations may cause problems in the identification of a native individual by the application of norms developed for different communities. Objective This study aimed to estimate the gender of skeletons by application of the method of Oliveira, et al. (1995), previously used in a population sample from Northeast Brazil. Material and Methods The accuracy of this method was assessed for a population from Southeast Brazil and validated by statistical tests. The method used two mandibular measurements, namely the bigonial distance and the mandibular ramus height. The sample was composed of 66 skulls and the method was applied by two examiners. The results were statistically analyzed by the paired t test, logistic discriminant analysis and logistic regression. Results The results demonstrated that the application of the method of Oliveira, et al. (1995) in this population achieved very different outcomes between genders, with 100% for females and only 11% for males, which may be explained by ethnic differences. However, statistical adjustment of measurement data for the population analyzed allowed accuracy of 76.47% for males and 78.13% for females, with the creation of a new discriminant formula. Conclusion It was concluded that methods involving physical anthropology present high rate of accuracy for human identification, easy application, low cost and simplicity; however, the methodologies must be validated for the different populations due to differences in ethnic patterns, which are directly related to the phenotypic aspects. In this specific case, the method of Oliveira, et al. (1995) presented good accuracy and may be used for gender estimation in Brazil in two geographic regions, namely Northeast and Southeast; however, for other regions of the country (North, Central West and South), previous methodological adjustment is recommended as demonstrated in this study. PMID:24037076

Validation of a physical anthropology methodology using mandibles for gender estimation in a Brazilian population.

PubMed

Carvalho, Suzana Papile Maciel; Brito, Liz Magalhães; Paiva, Luiz Airton Saavedra de; Bicudo, Lucilene Arilho Ribeiro; Crosato, Edgard Michel; Oliveira, Rogério Nogueira de

2013-01-01

Validation studies of physical anthropology methods in the different population groups are extremely important, especially in cases in which the population variations may cause problems in the identification of a native individual by the application of norms developed for different communities. This study aimed to estimate the gender of skeletons by application of the method of Oliveira, et al. (1995), previously used in a population sample from Northeast Brazil. The accuracy of this method was assessed for a population from Southeast Brazil and validated by statistical tests. The method used two mandibular measurements, namely the bigonial distance and the mandibular ramus height. The sample was composed of 66 skulls and the method was applied by two examiners. The results were statistically analyzed by the paired t test, logistic discriminant analysis and logistic regression. The results demonstrated that the application of the method of Oliveira, et al. (1995) in this population achieved very different outcomes between genders, with 100% for females and only 11% for males, which may be explained by ethnic differences. However, statistical adjustment of measurement data for the population analyzed allowed accuracy of 76.47% for males and 78.13% for females, with the creation of a new discriminant formula. It was concluded that methods involving physical anthropology present high rate of accuracy for human identification, easy application, low cost and simplicity; however, the methodologies must be validated for the different populations due to differences in ethnic patterns, which are directly related to the phenotypic aspects. In this specific case, the method of Oliveira, et al. (1995) presented good accuracy and may be used for gender estimation in Brazil in two geographic regions, namely Northeast and Southeast; however, for other regions of the country (North, Central West and South), previous methodological adjustment is recommended as demonstrated in this study.

Association between ErbB4 single nucleotide polymorphisms and susceptibility to schizophrenia: A meta-analysis of case-control studies.

PubMed

Feng, Yanguo; Cheng, Dejun; Zhang, Chaofeng; Li, Yuchun; Zhang, Zhiying; Wang, Juan; Feng, Xiao

2017-02-01

Accumulating studies have reported inconsistent association between ErbB4 single nucleotide polymorphisms (SNPs) and predisposition to schizophrenia. To better interpret this issue, here we conducted a meta-analysis using published case-control studies. We conducted a systematic search of MEDLINE (Pubmed), Embase (Ovid), Web of Science (Thomson-Reuters) to identify relevant references. The association between ErbB4 SNPs and schizophrenia was assessed by odds ratios (ORs) and 95% confidence intervals (CIs). Between-study heterogeneity was evaluated by I squared (I) statistics and Cochran's Q test. To appraise the stability of results, we employed sensitivity analysis by omitting 1 single study each time. To assess the potential publication bias, we conducted trim and fill analysis. Seven studies published in English comprising 3162 cases and 4264 controls were included in this meta-analysis. Meta-analyses showed that rs707284 is statistically significantly associated with schizophrenia susceptibility among Asian and Caucasian populations under the allelic model (OR = 0.91, 95% CI: 0.83-0.99, P = 0.035). Additionally, a marginal association (P < 0.1) was observed between rs707284 and schizophrenia risk among Asian and Caucasian populations under the recessive (OR = 0.85, 95% CI: 0.72-1.01, P = 0.065) and homozygous (OR = 0.84, 95% CI: 0.68-1.03, P = 0.094) models. In the Asian subgroup, rs707284 was also noted to be marginally associated with schizophrenia under the recessive model (OR = 0.84, 95% CI: 0.70-1.00, P = 0.053). However, no statistically significant association was found between rs839523, rs7598440, rs3748962, and rs2371276 and schizophrenia risk. This meta-analysis suggested that rs707284 may be a potential ErbB4 SNP associated with susceptibility to schizophrenia. Nevertheless, due to the limited sample size in this meta-analysis, more large-scale association studies are still needed to confirm the results.

Hierarchical models and the analysis of bird survey information

USGS Publications Warehouse

Sauer, J.R.; Link, W.A.

2003-01-01

Management of birds often requires analysis of collections of estimates. We describe a hierarchical modeling approach to the analysis of these data, in which parameters associated with the individual species estimates are treated as random variables, and probability statements are made about the species parameters conditioned on the data. A Markov-Chain Monte Carlo (MCMC) procedure is used to fit the hierarchical model. This approach is computer intensive, and is based upon simulation. MCMC allows for estimation both of parameters and of derived statistics. To illustrate the application of this method, we use the case in which we are interested in attributes of a collection of estimates of population change. Using data for 28 species of grassland-breeding birds from the North American Breeding Bird Survey, we estimate the number of species with increasing populations, provide precision-adjusted rankings of species trends, and describe a measure of population stability as the probability that the trend for a species is within a certain interval. Hierarchical models can be applied to a variety of bird survey applications, and we are investigating their use in estimation of population change from survey data.

Modeling urbanization patterns at a global scale with generative adversarial networks

NASA Astrophysics Data System (ADS)

Albert, A. T.; Strano, E.; Gonzalez, M.

2017-12-01

Current demographic projections show that, in the next 30 years, global population growth will mostly take place in developing countries. Coupled with a decrease in density, such population growth could potentially double the land occupied by settlements by 2050. The lack of reliable and globally consistent socio-demographic data, coupled with the limited predictive performance underlying traditional urban spatial explicit models, call for developing better predictive methods, calibrated using a globally-consistent dataset. Thus, richer models of the spatial interplay between the urban built-up land, population distribution and energy use are central to the discussion around the expansion and development of cities, and their impact on the environment in the context of a changing climate. In this talk we discuss methods for, and present an analysis of, urban form, defined as the spatial distribution of macroeconomic quantities that characterize a city, using modern machine learning methods and best-available remote-sensing data for the world's largest 25,000 cities. We first show that these cities may be described by a small set of patterns in radial building density, nighttime luminosity, and population density, which highlight, to first order, differences in development and land use across the world. We observe significant, spatially-dependent variance around these typical patterns, which would be difficult to model using traditional statistical methods. We take a first step in addressing this challenge by developing CityGAN, a conditional generative adversarial network model for simulating realistic urban forms. To guide learning and measure the quality of the simulated synthetic cities, we develop a specialized loss function for GAN optimization that incorporates standard spatial statistics used by urban analysis experts. Our framework is a stark departure from both the standard physics-based approaches in the literature (that view urban forms as fractals with a scale-free behavior), and the traditional statistical learning approaches (whereby values of individual pixels are modeled as functions of locally-defined, hand-engineered features). This is a first-of-its-kind analysis of urban forms using data at a planetary scale.

Statistical ecology comes of age.

PubMed

Gimenez, Olivier; Buckland, Stephen T; Morgan, Byron J T; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-12-01

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1-4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data.

Statistical ecology comes of age

PubMed Central

Gimenez, Olivier; Buckland, Stephen T.; Morgan, Byron J. T.; Bez, Nicolas; Bertrand, Sophie; Choquet, Rémi; Dray, Stéphane; Etienne, Marie-Pierre; Fewster, Rachel; Gosselin, Frédéric; Mérigot, Bastien; Monestiez, Pascal; Morales, Juan M.; Mortier, Frédéric; Munoz, François; Ovaskainen, Otso; Pavoine, Sandrine; Pradel, Roger; Schurr, Frank M.; Thomas, Len; Thuiller, Wilfried; Trenkel, Verena; de Valpine, Perry; Rexstad, Eric

2014-01-01

The desire to predict the consequences of global environmental change has been the driver towards more realistic models embracing the variability and uncertainties inherent in ecology. Statistical ecology has gelled over the past decade as a discipline that moves away from describing patterns towards modelling the ecological processes that generate these patterns. Following the fourth International Statistical Ecology Conference (1–4 July 2014) in Montpellier, France, we analyse current trends in statistical ecology. Important advances in the analysis of individual movement, and in the modelling of population dynamics and species distributions, are made possible by the increasing use of hierarchical and hidden process models. Exciting research perspectives include the development of methods to interpret citizen science data and of efficient, flexible computational algorithms for model fitting. Statistical ecology has come of age: it now provides a general and mathematically rigorous framework linking ecological theory and empirical data. PMID:25540151

Asymptotic Linear Spectral Statistics for Spiked Hermitian Random Matrices

NASA Astrophysics Data System (ADS)

Passemier, Damien; McKay, Matthew R.; Chen, Yang

2015-07-01

Using the Coulomb Fluid method, this paper derives central limit theorems (CLTs) for linear spectral statistics of three "spiked" Hermitian random matrix ensembles. These include Johnstone's spiked model (i.e., central Wishart with spiked correlation), non-central Wishart with rank-one non-centrality, and a related class of non-central matrices. For a generic linear statistic, we derive simple and explicit CLT expressions as the matrix dimensions grow large. For all three ensembles under consideration, we find that the primary effect of the spike is to introduce an correction term to the asymptotic mean of the linear spectral statistic, which we characterize with simple formulas. The utility of our proposed framework is demonstrated through application to three different linear statistics problems: the classical likelihood ratio test for a population covariance, the capacity analysis of multi-antenna wireless communication systems with a line-of-sight transmission path, and a classical multiple sample significance testing problem.

16(th) IHIW: analysis of HLA population data, with updated results for 1996 to 2012 workshop data (AHPD project report).

PubMed

Riccio, M E; Buhler, S; Nunes, J M; Vangenot, C; Cuénod, M; Currat, M; Di, D; Andreani, M; Boldyreva, M; Chambers, G; Chernova, M; Chiaroni, J; Darke, C; Di Cristofaro, J; Dubois, V; Dunn, P; Edinur, H A; Elamin, N; Eliaou, J-F; Grubic, Z; Jaatinen, T; Kanga, U; Kervaire, B; Kolesar, L; Kunachiwa, W; Lokki, M L; Mehra, N; Nicoloso, G; Paakkanen, R; Voniatis, D Papaioannou; Papasteriades, C; Poli, F; Richard, L; Romón Alonso, I; Slavčev, A; Sulcebe, G; Suslova, T; Testi, M; Tiercy, J-M; Varnavidou, A; Vidan-Jeras, B; Wennerström, A; Sanchez-Mazas, A

2013-02-01

We present here the results of the Analysis of HLA Population Data (AHPD) project of the 16th International HLA and Immunogenetics Workshop (16IHIW) held in Liverpool in May-June 2012. Thanks to the collaboration of 25 laboratories from 18 different countries, HLA genotypic data for 59 new population samples (either well-defined populations or donor registry samples) were gathered and 55 were analysed statistically following HLA-NET recommendations. The new data included, among others, large sets of well-defined populations from north-east Europe and West Asia, as well as many donor registry data from European countries. The Gene[rate] computer tools were combined to create a Gene[rate] computer pipeline to automatically (i) estimate allele frequencies by an expectation-maximization algorithm accommodating ambiguities, (ii) estimate heterozygosity, (iii) test for Hardy-Weinberg equilibrium (HWE), (iv) test for selective neutrality, (v) generate frequency graphs and summary statistics for each sample at each locus and (vi) plot multidimensional scaling (MDS) analyses comparing the new samples with previous IHIW data. Intrapopulation analyses show that HWE is rarely rejected, while neutrality tests often indicate a significant excess of heterozygotes compared with neutral expectations. The comparison of the 16IHIW AHPD data with data collected during previous workshops (12th-15th) shows that geography is an excellent predictor of HLA genetic differentiations for HLA-A, -B and -DRB1 loci but not for HLA-DQ, whose patterns are probably more influenced by natural selection. In Europe, HLA genetic variation clearly follows a north to south-east axis despite a low level of differentiation between European, North African and West Asian populations. Pacific populations are genetically close to Austronesian-speaking South-East Asian and Taiwanese populations, in agreement with current theories on the peopling of Oceania. Thanks to this project, HLA genetic variation is more clearly defined worldwide and better interpreted in relation to human peopling history and HLA molecular evolution. © 2012 Blackwell Publishing Ltd.

Ethnic variation of selected dental traits in Coorg

PubMed Central

Uthaman, Chancy; Sequeira, Peter Simon; Jain, Jithesh

2015-01-01

Purpose: In a country like India, in addition to the great innate diversity, there are distinct migrant populations with unique dental traits. Aim: To assess the distribution and degree of expression of cusp of Carabelli of maxillary first permanent molars and shoveling trait of maxillary central incisors, between three ethnic groups of Coorg, namely Kodavas, Tibetans, and Malayalees. Materials and Methods: A cross-sectional, indirect, anthropometric, study was carried out among 15- to 30-year-old subjects belonging to three different ethnic origins. A random sample consisting of 91 subjects were recruited for the study. The shovel trait of incisors and the Carabelli trait of molars were recorded according to the classification given by Hrdliƈka and Sousa et al., respectively. Statistical Analysis: The Kruskal-Wallis test was employed to determine the difference in three populations for shoveling and Carabelli traits. Mann-Whitney Test was used for pair-wise comparisons of three populations. Result: Of the total 91 subjects, 31 were Kodavas, 30 Malayalees and 30 Tibetans. There was a statistically significant difference in shoveling trait among the three ethnic groups. For Carabelli traits, there was no statistically significant difference among three ethnic groups. Conclusion: The present study findings showed that Tibetans have a higher degree of shoveling trait than the selected South Indian ethnic groups. PMID:26816457

Multivariate meta-analysis of individual participant data helped externally validate the performance and implementation of a prediction model.

PubMed

Snell, Kym I E; Hua, Harry; Debray, Thomas P A; Ensor, Joie; Look, Maxime P; Moons, Karel G M; Riley, Richard D

2016-01-01

Our aim was to improve meta-analysis methods for summarizing a prediction model's performance when individual participant data are available from multiple studies for external validation. We suggest multivariate meta-analysis for jointly synthesizing calibration and discrimination performance, while accounting for their correlation. The approach estimates a prediction model's average performance, the heterogeneity in performance across populations, and the probability of "good" performance in new populations. This allows different implementation strategies (e.g., recalibration) to be compared. Application is made to a diagnostic model for deep vein thrombosis (DVT) and a prognostic model for breast cancer mortality. In both examples, multivariate meta-analysis reveals that calibration performance is excellent on average but highly heterogeneous across populations unless the model's intercept (baseline hazard) is recalibrated. For the cancer model, the probability of "good" performance (defined by C statistic ≥0.7 and calibration slope between 0.9 and 1.1) in a new population was 0.67 with recalibration but 0.22 without recalibration. For the DVT model, even with recalibration, there was only a 0.03 probability of "good" performance. Multivariate meta-analysis can be used to externally validate a prediction model's calibration and discrimination performance across multiple populations and to evaluate different implementation strategies. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

[Burnout syndrome in teachers from two universities in Popayán, Colombia].

PubMed

Correa-Correa, Zamanda; Muñoz-Zambrano, Isabel; Chaparro, Andrés F

2010-08-01

Evaluating professional exhaustion or burnout syndrome: background, syndrome and consequences amongst half-time and full-time staff working in two private universities in the city of Popayán during 2008. The study population included 44 male and female participants aged 20 to 40 who were evaluated by using a brief burnout questionnaire (BBQ). This questionnaire had been validated for Latin-American and for teachers. It was not exclusively focused on the structure of the syndrome itself but rather included background elements and consequences. The study was quantitative and cross-sectional, having a deductive hypothetical methodological focus. Descriptive statistics and the Chi-square test were used for data analysis, accepting p<0.05 statistical significance. The analysis was univariate and bivariate. The results indicated low burnout syndrome frequency in the study population. However, 9.1 % high depersonalization frequency was found (i.e. teachers had developed negative attitudes and were insensitive to those receiving their services) and 15.9 % and 9.1 % frequencies for high physical and social consequences, respectively. Bivariate analysis revealed significant association of several factors. The results indicated low burnout syndrome frequency in this population. However, factors which were highly associated with physical and social consequences were: being male, aged 20 to 40, having a marital relationship with a habitual partner, working full-time, working at home and spending more than 75 % of the working day interacting with the beneficiaries of the services being provided.

The genetics of East African populations: a Nilo-Saharan component in the African genetic landscape

PubMed Central

Dobon, Begoña; Hassan, Hisham Y.; Laayouni, Hafid; Luisi, Pierre; Ricaño-Ponce, Isis; Zhernakova, Alexandra; Wijmenga, Cisca; Tahir, Hanan; Comas, David; Netea, Mihai G.; Bertranpetit, Jaume

2015-01-01

East Africa is a strategic region to study human genetic diversity due to the presence of ethnically, linguistically, and geographically diverse populations. Here, we provide new insight into the genetic history of populations living in the Sudanese region of East Africa by analysing nine ethnic groups belonging to three African linguistic families: Niger-Kordofanian, Nilo-Saharan and Afro-Asiatic. A total of 500 individuals were genotyped for 200,000 single-nucleotide polymorphisms. Principal component analysis, clustering analysis using ADMIXTURE, FST statistics, and the three-population test were used to investigate the underlying genetic structure and ancestry of the different ethno-linguistic groups. Our analyses revealed a genetic component for Sudanese Nilo-Saharan speaking groups (Darfurians and part of Nuba populations) related to Nilotes of South Sudan, but not to other Sudanese populations or other sub-Saharan populations. Populations inhabiting the North of the region showed close genetic affinities with North Africa, with a component that could be remnant of North Africans before the migrations of Arabs from Arabia. In addition, we found very low genetic distances between populations in genes important for anti-malarial and anti-bacterial host defence, suggesting similar selective pressures on these genes and stressing the importance of considering functional pathways to understand the evolutionary history of populations. PMID:26017457

Transfusion Indication Threshold Reduction (TITRe2) randomized controlled trial in cardiac surgery: statistical analysis plan.

PubMed

Pike, Katie; Nash, Rachel L; Murphy, Gavin J; Reeves, Barnaby C; Rogers, Chris A

2015-02-22

The Transfusion Indication Threshold Reduction (TITRe2) trial is the largest randomized controlled trial to date to compare red blood cell transfusion strategies following cardiac surgery. This update presents the statistical analysis plan, detailing how the study will be analyzed and presented. The statistical analysis plan has been written following recommendations from the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use, prior to database lock and the final analysis of trial data. Outlined analyses are in line with the Consolidated Standards of Reporting Trials (CONSORT). The study aims to randomize 2000 patients from 17 UK centres. Patients are randomized to either a restrictive (transfuse if haemoglobin concentration <7.5 g/dl) or liberal (transfuse if haemoglobin concentration <9 g/dl) transfusion strategy. The primary outcome is a binary composite outcome of any serious infectious or ischaemic event in the first 3 months following randomization. The statistical analysis plan details how non-adherence with the intervention, withdrawals from the study, and the study population will be derived and dealt with in the analysis. The planned analyses of the trial primary and secondary outcome measures are described in detail, including approaches taken to deal with multiple testing, model assumptions not being met and missing data. Details of planned subgroup and sensitivity analyses and pre-specified ancillary analyses are given, along with potential issues that have been identified with such analyses and possible approaches to overcome such issues. ISRCTN70923932 .

The Relationship between Teaching Presence and Student Course Outcomes in an Online International Population

ERIC Educational Resources Information Center

Wendt, Jillian; Courduff, Jennifer

2018-01-01

A causal comparative research design was utilized in this study to examine the relationship between international students' perceptions of teacher presence in the online learning environment and students' achievement as measured by end of course grades. Spearman's analysis indicated no statistically significant correlation between the composite…

School Choice in Colorado Springs: The Relationship between Parental Decisions, Location and Neighbourhood Characteristics

ERIC Educational Resources Information Center

Theobald, Rebecca

2005-01-01

The influence of location as exemplified by neighbourhood factors and school characteristics on primary education is examined in the context of the school choice movement of the last two decades. The analysis incorporates statistical information about schools and population data from Census 2000 describing neighbourhoods and schools in one…

Women of the World: Sub-Saharan Africa.

ERIC Educational Resources Information Center

Newman, Jeanne S.

The second in a series of five handbooks designed to present and analyze statistical data on women in various regions of the world, this handbook focuses on women in 40 countries of Sub-Saharan Africa. Beginning with an overview of population characteristics in the region, the analysis continues with a description of women's literacy and…

The Potential for Differential Findings among Invariance Testing Strategies for Multisample Measured Variable Path Models

ERIC Educational Resources Information Center

Mann, Heather M.; Rutstein, Daisy W.; Hancock, Gregory R.

2009-01-01

Multisample measured variable path analysis is used to test whether causal/structural relations among measured variables differ across populations. Several invariance testing approaches are available for assessing cross-group equality of such relations, but the associated test statistics may vary considerably across methods. This study is a…

Estimation procedures for the combined 1990s periodic forest inventories of California, Oregon, and Washington.

Treesearch

T.M. Barrett

2004-01-01

During the 1990s, forest inventories for California, Oregon, and Washington were conducted by different agencies using different methods. The Pacific Northwest Research Station Forest Inventory and Analysis program recently integrated these inventories into a single database. This document briefly describes potential statistical methods for estimating population totals...

Getting the Measure of the VET Professional

ERIC Educational Resources Information Center

Mlotkowski, Peter; Guthrie, Hugh

2010-01-01

This report draws on analyses of Australian Bureau of Statistics (ABS) data from the Survey of Education and Training (SET) and the Census of Population and Housing to provide an updated demographic profile of vocational education and training (VET) professionals and VET practitioners. A number of caveats are attached to this analysis, all…

Construct Equivalence of a National Certification Examination that Uses Dual Languages and Audio Assistance

ERIC Educational Resources Information Center

Wang, Shudong; Wang, Ning; Hoadley, David

2007-01-01

This study used confirmatory factor analysis (CFA) to examine the comparability of the National Nurse Aide Assessment Program (NNAAP[TM]) test scores across language and administration condition groups for calibration and validation samples that were randomly drawn from the same population. Fit statistics supported both the calibration and…

Understanding Crystal Populations; Looking Towards 3D Quantitative Analysis

NASA Astrophysics Data System (ADS)

Jerram, D. A.; Morgan, D. J.

2010-12-01

In order to understand volcanic systems, the potential record held within crystal populations needs to be revealed. It is becoming increasingly clear, however, that the crystal populations that arrive at the surface in volcanic eruptions are commonly mixtures of crystals, which may be representative of simple crystallization, recycling of crystals and incorporation of alien crystals. If we can quantify the true 3D population within a sample then we will be able to separate crystals with different histories and begin to interrogate the true and complex plumbing within the volcanic system. Modeling crystal populations is one area where we can investigate the best methodologies to use when dealing with sections through 3D populations. By producing known 3D shapes and sizes with virtual textures and looking at the statistics of shape and size when such populations are sectioned, we are able to gain confidence about what our 2D information is telling us about the population. We can also use this approach to test the size of population we need to analyze. 3D imaging through serial sectioning or x-ray CT, provides a complete 3D quantification of a rocks texture. Individual phases can be identified and in principle the true 3D statistics of the population can be interrogated. In practice we need to develop strategies (as with 2D-3D transformations), that enable a true characterization of the 3D data, and an understanding of the errors and pitfalls that exist. Ultimately, the reproduction of true 3D textures and the wealth of information they hold, is now within our reach.

Declining scaup populations: A retrospective analysis of long-term population and harvest survey data

USGS Publications Warehouse

Afton, A.D.; Anderson, M.G.

2001-01-01

We examined long-term databases concerning population status of scaup (lesser [Aythya affinis] and greater scaup [A. marila] combined) and harvest statistics of lesser scaup to identify factors potentially limiting population growth. Specifically, we explored evidence for and against the general hypotheses that scaup populations have declined in association with declining recruitment and/or female survival. We examined geographic heterogeneity in scaup demographic patterns that could yield evidence about potential limiting factors. Several biases exist in survey methodology used to estimate scaup populations and harvest statistics; however, none of these biases likely accounted for our major findings that (1) the continental scaup breeding population has declined over the last 20 years, with widespread and consistent declines within surveyed areas of the Canadian western boreal forest where most lesser scaup breed; (2) sex ratios of lesser scaup in the U.S. harvest have increased (more males now relative to females); and (3) age ratios of lesser scaup in the U.S. harvest have declined (fewer immatures now relative to adults), especially in the midcontinent region. We interpreted these major findings as evidence that (1) recruitment of lesser scaup has declined over the last 20 years, particularly in the Canadian western boreal forest; and (2) survival of female lesser scaup has declined relative to that of males. We found little evidence that harvest was associated with the scaup population decline. Our findings underscore the need for both improvements and changes to population survey procedures and new research to discriminate among various hypotheses explaining the recent scaup population decline.

The congruence between matrilineal genetic (mtDNA) and geographic diversity of Iranians and the territorial populations

PubMed Central

Bahmanimehr, Ardeshir; Eskandari, Ghafar; Nikmanesh, Fatemeh

2015-01-01

Objective(s): From the ancient era, emergence of Agriculture in the connecting region of Mesopotamia and the Iranian plateau at the foothills of the Zagros Mountains, made Iranian gene pool as an important source of populating the region. It has differentiated the population spread and different language groups. In order to trace the maternal genetic affinity between Iranians and other populations of the area and to establish the place of Iranians in a broad framework of ethnically and linguistically diverse groups of Middle Eastern and South Asian populations, a comparative study of territorial groups was designed and used in the population statistical analysis. Materials and Methods: Mix of 616 samples was sequenced for complete mtDNA or hyper variable regions in this study. A published dataset of neighboring populations was used as a comparison in the Iranian matrilineal lineage study based on mtDNA haplogroups. Results: Statistical analyses data, demonstrate a close genetic structure of all Iranian populations, thus suggesting their origin from a common maternal ancestral gene pool and show that the diverse maternal genetic structure does not reflect population differentiation in the region in their language. Conclusion: In the aggregate of the eastward spreads of proto-Elamo-Dravidian language from the Southwest region of Iran, the Elam province, a reasonable degree of homogeneity has been observed among Iranians in this study. The approach will facilitate our perception of the more detailed relationship of the ethnic groups living in Iran with the other ancient peoples of the area, testing linguistic hypothesis and population movements. PMID:25810873

Genetic admixture and lineage separation in a southern Andean plant

PubMed Central

Morello, Santiago; Sede, Silvana M.

2016-01-01

Mountain uplifts have generated new ecologic opportunities for plants, and triggered evolutionary processes, favouring an increase on the speciation rate in all continents. Moreover, mountain ranges may act as corridors or barriers for plant lineages and populations. In South America a high rate of diversification has been linked to Andean orogeny during Pliocene/Miocene. More recently, Pleistocene glacial cycles have also shaped species distribution and demography. The endemic genus Escallonia is known to have diversified in the Andes. Species with similar morphology obscure species delimitation and plants with intermediate characters occur naturally. The aim of this study is to characterize genetic variation and structure of two widespread species of Escallonia: E. alpina and E. rubra. We analyzed the genetic variation of populations of the entire distribution range of the species and we also included those with intermediate morphological characters; a total of 94 accessions from 14 populations were used for the Amplified Fragment Length Polymorphism (AFLP) analysis. Plastid DNA sequences (trnS-trnG, 3′trnV-ndhC intergenic spacers and the ndhF gene) from sixteen accessions of Escallonia species were used to construct a Statistical Parsimony network. Additionally, we performed a geometric morphometrics analysis on 88 leaves from 35 individuals of the two E. alpina varieties to further study their differences. Wright’s Fst and analysis of molecular variance tests performed on AFLP data showed a significant level of genetic structure at the species and population levels. Intermediate morphology populations showed a mixed genetic contribution from E. alpina var. alpina and E. rubra both in the Principal Coordinates Analysis (PCoA) and STRUCTURE. On the other hand, E. rubra and the two varieties of E. alpina are well differentiated and assigned to different genetic clusters. Moreover, the Statistical Parsimony network showed a high degree of divergence between the varieties of E. alpina: var. alpina is more closely related to E. rubra and other species than to its own counterpart E. alpina var. carmelitana. Geometric morphometrics analysis (Elliptic Fourier descriptors) revealed significant differences in leaf shape between varieties. We found that diversity in Escallonia species analyzed here is geographically structured and deep divergence between varieties of E. alpina could be associated to ancient evolutionary events like orogeny. Admixture in southern populations could be the result of hybridization at the margins of the parental species’ distribution range. PMID:27179539

The unauthorized Mexican immigrant population and welfare in Los Angeles County: a comparative statistical analysis.

PubMed

Marcelli, E A; Heer, D M

1998-01-01

"Using a unique 1994 Los Angeles County Household Survey of foreign-born Mexicans and the March 1994 and 1995 Current Population Surveys, we estimate the number of unauthorized Mexican immigrants (UMIs) residing in Los Angeles County, and compare their use of seven welfare programs with that of other non-U.S. citizens and U.S. citizens. Non-U.S. citizens were found to be no more likely than U.S. citizens to have used welfare, and UMIs were 11% (14%) less likely than other non-citizens (U.S.-born citizens).... We demonstrate how results differ depending on the unit of analysis employed, and on which programs constitute ¿welfare'." excerpt

Karyomorphometric analysis of Fritillaria montana group in Greece.

PubMed

Samaropoulou, Sofia; Bareka, Pepy; Kamari, Georgia

2016-01-01

Fritillaria Linnaeus, 1753 (Liliaceae) is a genus of geophytes, represented in Greece by 29 taxa. Most of the Greek species are endemic to the country and/or threatened. Although their classical cytotaxonomic studies have already been presented, no karyomorphometric analysis has ever been given. In the present study, the cytological results of Fritillaria montana Hoppe ex W.D.J. Koch, 1832 group, which includes Fritillaria epirotica Turrill ex Rix, 1975 and Fritillaria montana are statistically evaluated for the first time. Further indices about interchromosomal and intrachromosomal asymmetry are given. A new population of Fritillaria epirotica is also investigated, while for Fritillaria montana , a diploid individual was found in a known as triploid population. Paired t-tests and PCoA analysis have been applied to compare the two species.

Geographic Clusters of Basal Cell Carcinoma in a Northern California Health Plan Population.

PubMed

Ray, G Thomas; Kulldorff, Martin; Asgari, Maryam M

2016-11-01

Rates of skin cancer, including basal cell carcinoma (BCC), the most common cancer, have been increasing over the past 3 decades. A better understanding of geographic clustering of BCCs can help target screening and prevention efforts. Present a methodology to identify spatial clusters of BCC and identify such clusters in a northern California population. This retrospective study used a BCC registry to determine rates of BCC by census block group, and used spatial scan statistics to identify statistically significant geographic clusters of BCCs, adjusting for age, sex, and socioeconomic status. The study population consisted of white, non-Hispanic members of Kaiser Permanente Northern California during years 2011 and 2012. Statistically significant geographic clusters of BCC as determined by spatial scan statistics. Spatial analysis of 28 408 individuals who received a diagnosis of at least 1 BCC in 2011 or 2012 revealed distinct geographic areas with elevated BCC rates. Among the 14 counties studied, BCC incidence ranged from 661 to 1598 per 100 000 person-years. After adjustment for age, sex, and neighborhood socioeconomic status, a pattern of 5 discrete geographic clusters emerged, with a relative risk ranging from 1.12 (95% CI, 1.03-1.21; P = .006) for a cluster in eastern Sonoma and northern Napa Counties to 1.40 (95% CI, 1.15-1.71; P < .001) for a cluster in east Contra Costa and west San Joaquin Counties, compared with persons residing outside that cluster. In this study of a northern California population, we identified several geographic clusters with modestly elevated incidence of BCC. Knowledge of geographic clusters can help inform future research on the underlying etiology of the clustering including factors related to the environment, health care access, or other characteristics of the resident population, and can help target screening efforts to areas of highest yield.

Demographic and health attributes of the Nahua, initial contact population of the Peruvian Amazon.

PubMed

Culqui, Dante R; Ayuso-Alvarez, Ana; Munayco, Cesar V; Quispe-Huaman, Carlos; Mayta-Tristán, Percy; Campos, Juan de Mata Donado

2016-01-01

We present the case of the Nahua population of Santa Rosa de Serjali, Peruvian Amazon's population, considered of initial contact. This population consists of human groups that for a long time decided to live in isolation, but lately have begun living a more sedentary lifestyle and in contact with Western populations. There are two fully identified initial contact groups in Peru: the Nahua and the Nanti. The health statistics of the Nahua are scarce. This study offers an interpretation of demographic and epidemiological indicators of the Nahua people, trying to identify if a certain degree of health vulnerability exists. We performed a cross sectional study, and after analyzing their health indicators, as well as the supplemental qualitative analysis of the population, brought us to conclude that in 2006, the Nahua, remained in a state of health vulnerability.

PROBABILITY SAMPLING AND POPULATION INFERENCE IN MONITORING PROGRAMS

EPA Science Inventory

A fundamental difference between probability sampling and conventional statistics is that "sampling" deals with real, tangible populations, whereas "conventional statistics" usually deals with hypothetical populations that have no real-world realization. he focus here is on real ...

Metro U.S.A. Data Sheet: Population Estimates and Selected Demographic Indicators for the Metropolitan Areas of the United States. Special edition of the United States Population Data Sheet.

ERIC Educational Resources Information Center

Population Reference Bureau, Inc., Washington, DC.

This poster-size data sheet presents population estimates and selected demographic indicators for the nation's 281 metropolitan areas. These areas are divided into 261 Metropolitan Statistical Areas (MSAs) and 20 Consolidated Metropolitan Statistical Areas (CMSAs), reporting units which replace the Standard Metropolitan Statistical Areas (SMSAs)…

A Statistical Analysis of the Economic Drivers of Battery Energy Storage in Commercial Buildings: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Matthew; Simpkins, Travis; Cutler, Dylan

There is significant interest in using battery energy storage systems (BESS) to reduce peak demand charges, and therefore the life cycle cost of electricity, in commercial buildings. This paper explores the drivers of economic viability of BESS in commercial buildings through statistical analysis. A sample population of buildings was generated, a techno-economic optimization model was used to size and dispatch the BESS, and the resulting optimal BESS sizes were analyzed for relevant predictor variables. Explanatory regression analyses were used to demonstrate that peak demand charges are the most significant predictor of an economically viable battery, and that the shape ofmore » the load profile is the most significant predictor of the size of the battery.« less

A Statistical Analysis of the Economic Drivers of Battery Energy Storage in Commercial Buildings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Matthew; Simpkins, Travis; Cutler, Dylan

There is significant interest in using battery energy storage systems (BESS) to reduce peak demand charges, and therefore the life cycle cost of electricity, in commercial buildings. This paper explores the drivers of economic viability of BESS in commercial buildings through statistical analysis. A sample population of buildings was generated, a techno-economic optimization model was used to size and dispatch the BESS, and the resulting optimal BESS sizes were analyzed for relevant predictor variables. Explanatory regression analyses were used to demonstrate that peak demand charges are the most significant predictor of an economically viable battery, and that the shape ofmore » the load profile is the most significant predictor of the size of the battery.« less

Analysis of impact crater populations and the geochronology of planetary surfaces in the inner solar system

NASA Astrophysics Data System (ADS)

Fassett, Caleb I.

2016-10-01

Analyzing the density of impact craters on planetary surfaces is the only known technique for learning their ages remotely. As a result, crater statistics have been widely analyzed on the terrestrial planets, since the timing and rates of activity are critical to understanding geologic process and history. On the Moon, the samples obtained by the Apollo and Luna missions provide critical calibration points for cratering chronology. On Mercury, Venus, and Mars, there are no similarly firm anchors for cratering rates, but chronology models have been established by extrapolating from the lunar record or by estimating their impactor fluxes in other ways. This review provides a current perspective on crater population measurements and their chronological interpretation. Emphasis is placed on how ages derived from crater statistics may be contingent on assumptions that need to be considered critically. In addition, ages estimated from crater populations are somewhat different than ages from more familiar geochronology tools (e.g., radiometric dating). Resurfacing processes that remove craters from the observed population are particularly challenging to account for, since they can introduce geologic uncertainty into results or destroy information about the formation age of a surface. Regardless of these challenges, crater statistics measurements have resulted in successful predictions later verified by other techniques, including the age of the lunar maria, the existence of a period of heavy bombardment in the Moon's first billion years, and young volcanism on Mars.

Assessment of trace elements levels in patients with Type 2 diabetes using multivariate statistical analysis.

PubMed

Badran, M; Morsy, R; Soliman, H; Elnimr, T

2016-01-01

The trace elements metabolism has been reported to possess specific roles in the pathogenesis and progress of diabetes mellitus. Due to the continuous increase in the population of patients with Type 2 diabetes (T2D), this study aims to assess the levels and inter-relationships of fast blood glucose (FBG) and serum trace elements in Type 2 diabetic patients. This study was conducted on 40 Egyptian Type 2 diabetic patients and 36 healthy volunteers (Hospital of Tanta University, Tanta, Egypt). The blood serum was digested and then used to determine the levels of 24 trace elements using an inductive coupled plasma mass spectroscopy (ICP-MS). Multivariate statistical analysis depended on correlation coefficient, cluster analysis (CA) and principal component analysis (PCA), were used to analysis the data. The results exhibited significant changes in FBG and eight of trace elements, Zn, Cu, Se, Fe, Mn, Cr, Mg, and As, levels in the blood serum of Type 2 diabetic patients relative to those of healthy controls. The statistical analyses using multivariate statistical techniques were obvious in the reduction of the experimental variables, and grouping the trace elements in patients into three clusters. The application of PCA revealed a distinct difference in associations of trace elements and their clustering patterns in control and patients group in particular for Mg, Fe, Cu, and Zn that appeared to be the most crucial factors which related with Type 2 diabetes. Therefore, on the basis of this study, the contributors of trace elements content in Type 2 diabetic patients can be determine and specify with correlation relationship and multivariate statistical analysis, which confirm that the alteration of some essential trace metals may play a role in the development of diabetes mellitus. Copyright © 2015 Elsevier GmbH. All rights reserved.

Large-scale analysis reveals populational contributions of cortical spike rate and synchrony to behavioural functions.

PubMed

Kimura, Rie; Saiki, Akiko; Fujiwara-Tsukamoto, Yoko; Sakai, Yutaka; Isomura, Yoshikazu

2017-01-01

There have been few systematic population-wide analyses of relationships between spike synchrony within a period of several milliseconds and behavioural functions. In this study, we obtained a large amount of spike data from > 23,000 neuron pairs by multiple single-unit recording from deep layer neurons in motor cortical areas in rats performing a forelimb movement task. The temporal changes of spike synchrony in the whole neuron pairs were statistically independent of behavioural changes during the task performance, although some neuron pairs exhibited correlated changes in spike synchrony. Mutual information analyses revealed that spike synchrony made a smaller contribution than spike rate to behavioural functions. The strength of spike synchrony between two neurons was statistically independent of the spike rate-based preferences of the pair for behavioural functions. Spike synchrony within a period of several milliseconds in presynaptic neurons enables effective integration of functional information in the postsynaptic neuron. However, few studies have systematically analysed the population-wide relationships between spike synchrony and behavioural functions. Here we obtained a sufficiently large amount of spike data among regular-spiking (putatively excitatory) and fast-spiking (putatively inhibitory) neuron subtypes (> 23,000 pairs) by multiple single-unit recording from deep layers in motor cortical areas (caudal forelimb area, rostral forelimb area) in rats performing a forelimb movement task. After holding a lever, rats pulled the lever either in response to a cue tone (external-trigger trials) or spontaneously without any cue (internal-trigger trials). Many neurons exhibited functional spike activity in association with forelimb movements, and the preference of regular-spiking neurons in the rostral forelimb area was more biased toward externally triggered movement than that in the caudal forelimb area. We found that a population of neuron pairs with spike synchrony does exist, and that some neuron pairs exhibit a dependence on movement phase during task performance. However, the population-wide analysis revealed that spike synchrony was statistically independent of the movement phase and the spike rate-based preferences of the pair for behavioural functions, whereas spike rates were clearly dependent on the movement phase. In fact, mutual information analyses revealed that the contribution of spike synchrony to the behavioural functions was small relative to the contribution of spike rate. Our large-scale analysis revealed that cortical spike rate, rather than spike synchrony, contributes to population coding for movement. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Fleeing to Fault Zones: Incorporating Syrian Refugees into Earthquake Risk Analysis along the East Anatolian and Dead Sea Rift Fault Zones

NASA Astrophysics Data System (ADS)

Wilson, B.; Paradise, T. R.

2016-12-01

The influx of millions of Syrian refugees into Turkey has rapidly changed the population distribution along the Dead Sea Rift and East Anatolian Fault zones. In contrast to other countries in the Middle East where refugees are accommodated in camp environments, the majority of displaced individuals in Turkey are integrated into cities, towns, and villages—placing stress on urban settings and increasing potential exposure to strong shaking. Yet, displaced populations are not traditionally captured in data sources used in earthquake risk analysis or loss estimations. Accordingly, we present a district-level analysis assessing the spatial overlap of earthquake hazards and refugee locations in southeastern Turkey to determine how migration patterns are altering seismic risk in the region. Using migration estimates from the U.S. Humanitarian Information Unit, we create three district-level population scenarios that combine official population statistics, refugee camp populations, and low, median, and high bounds for integrated refugee populations. We perform probabilistic seismic hazard analysis alongside these population scenarios to map spatial variations in seismic risk between 2011 and late 2015. Our results show a significant relative southward increase of seismic risk for this period due to refugee migration. Additionally, we calculate earthquake fatalities for simulated earthquakes using a semi-empirical loss estimation technique to determine degree of under-estimation resulting from forgoing migration data in loss modeling. We find that including refugee populations increased casualties by 11-12% using median population estimates, and upwards of 20% using high population estimates. These results communicate the ongoing importance of placing environmental hazards in their appropriate regional and temporal context which unites physical, political, cultural, and socio-economic landscapes. Keywords: Earthquakes, Hazards, Loss-Estimation, Syrian Crisis, Migration, Refugees

Genetic differentiation and origin of the Jordanian population: an analysis of Alu insertion polymorphisms.

PubMed

Bahri, Raoudha; El Moncer, Wifak; Al-Batayneh, Khalid; Sadiq, May; Esteban, Esther; Moral, Pedro; Chaabani, Hassen

2012-05-01

Although much of Jordan is covered by desert, its north-western region forms part of the Fertile Crescent region that had given a rich past to Jordanians. This past, scarcely described by historians, is not yet clarified by sufficient genetic data. Thus in this paper we aim to determine the genetic differentiation of the Jordanian population and to discuss its origin. A total of 150 unrelated healthy Jordanians were investigated for ten Alu insertion polymorphisms. Genetic relationships among populations were estimated by a principal component (PC) plot based on the analyses of the R-matrix software. Statistical analysis showed that the Jordanian population is not significantly different from the United Arab Emirates population or the North Africans. This observation, well represented in PC plot, suggests a common origin of these populations belonging respectively to ancient Mesopotamia, Arabia, and North Africa. Our results are compatible with ancient peoples' movements from Arabia to ancient Mesopotamia and North Africa as proposed by historians and supported by previous genetic results. The original genetic profile of the Jordanian population, very likely Arabian Semitic, has not been subject to significant change despite the succession of several civilizations.

Patterns of genetic and morphometric diversity in baobab (Adansonia digitata) populations across different climatic zones of Benin (West Africa).

PubMed

Assogbadjo, A E; Kyndt, T; Sinsin, B; Gheysen, G; van Damme, P

2006-05-01

Baobab (Adansonia digitata) is a multi-purpose tree used daily by rural African communities. The present study aimed at investigating the level of morphometric and genetic variation and spatial genetic structure within and between threatened baobab populations from the three climatic zones of Benin. A total of 137 individuals from six populations were analysed using morphometric data as well as molecular marker data generated using the AFLP technique. Five primer pairs resulted in a total of 217 scored bands with 78.34 % of them being polymorphic. A two-level AMOVA of 137 individuals from six baobab populations revealed 82.37 % of the total variation within populations and 17.63 % among populations (P < 0.001). Analysis of population structure with allele-frequency based F-statistics revealed a global F(ST) of 0.127 +/- 0.072 (P < 0.001). The mean gene diversity within populations (H(S)) and the average gene diversity between populations (D(ST)) were estimated at 0.309 +/- 0.000 and 0.045 +/- 0.072, respectively. Baobabs in the Sudanian and Sudan-Guinean zones of Benin were short and produced the highest yields of pulp, seeds and kernels, in contrast to the ones in the Guinean zone, which were tall and produced only a small number of fruits with a low pulp, seed and kernel productivity. A statistically significant correlation with the observed patterns of genetic diversity was observed for three morphological characteristics: height of the trees, number of branches and thickness of the capsules. The results indicate some degree of physical isolation of the populations collected in the different climatic zones and suggest a substantial amount of genetic structuring between the analysed populations of baobab. Sampling options of the natural populations are suggested for in or ex situ conservation.

The contribution of statistical physics to evolutionary biology.

PubMed

de Vladar, Harold P; Barton, Nicholas H

2011-08-01

Evolutionary biology shares many concepts with statistical physics: both deal with populations, whether of molecules or organisms, and both seek to simplify evolution in very many dimensions. Often, methodologies have undergone parallel and independent development, as with stochastic methods in population genetics. Here, we discuss aspects of population genetics that have embraced methods from physics: non-equilibrium statistical mechanics, travelling waves and Monte-Carlo methods, among others, have been used to study polygenic evolution, rates of adaptation and range expansions. These applications indicate that evolutionary biology can further benefit from interactions with other areas of statistical physics; for example, by following the distribution of paths taken by a population through time. Copyright © 2011 Elsevier Ltd. All rights reserved.

Estimating chronic disease rates in Canada: which population-wide denominator to use?

PubMed

Ellison, J; Nagamuthu, C; Vanderloo, S; McRae, B; Waters, C

2016-10-01

Chronic disease rates are produced from the Public Health Agency of Canada's Canadian Chronic Disease Surveillance System (CCDSS) using administrative health data from provincial/territorial health ministries. Denominators for these rates are based on estimates of populations derived from health insurance files. However, these data may not be accessible to all researchers. Another source for population size estimates is the Statistics Canada census. The purpose of our study was to calculate the major differences between the CCDSS and Statistics Canada's population denominators and to identify the sources or reasons for the potential differences between these data sources. We compared the 2009 denominators from the CCDSS and Statistics Canada. The CCDSS denominator was adjusted for the growth components (births, deaths, emigration and immigration) from Statistics Canada's census data. The unadjusted CCDSS denominator was 34 429 804, 3.2% higher than Statistics Canada's estimate of population in 2009. After the CCDSS denominator was adjusted for the growth components, the difference between the two estimates was reduced to 431 323 people, a difference of 1.3%. The CCDSS overestimates the population relative to Statistics Canada overall. The largest difference between the two estimates was from the migrant growth component, while the smallest was from the emigrant component. By using data descriptions by data source, researchers can make decisions about which population to use in their calculations of disease frequency.

An optimal stratified Simon two-stage design.

PubMed

Parashar, Deepak; Bowden, Jack; Starr, Colin; Wernisch, Lorenz; Mander, Adrian

2016-07-01

In Phase II oncology trials, therapies are increasingly being evaluated for their effectiveness in specific populations of interest. Such targeted trials require designs that allow for stratification based on the participants' molecular characterisation. A targeted design proposed by Jones and Holmgren (JH) Jones CL, Holmgren E: 'An adaptive Simon two-stage design for phase 2 studies of targeted therapies', Contemporary Clinical Trials 28 (2007) 654-661.determines whether a drug only has activity in a disease sub-population or in the wider disease population. Their adaptive design uses results from a single interim analysis to decide whether to enrich the study population with a subgroup or not; it is based on two parallel Simon two-stage designs. We study the JH design in detail and extend it by providing a few alternative ways to control the familywise error rate, in the weak sense as well as the strong sense. We also introduce a novel optimal design by minimising the expected sample size. Our extended design contributes to the much needed framework for conducting Phase II trials in stratified medicine. © 2016 The Authors Pharmaceutical Statistics Published by John Wiley & Sons Ltd. © 2016 The Authors Pharmaceutical Statistics Published by John Wiley & Sons Ltd.

Population limitation in a non-cyclic arctic fox population in a changing climate.

PubMed

Pálsson, Snæbjörn; Hersteinsson, Páll; Unnsteinsdóttir, Ester R; Nielsen, Ólafur K

2016-04-01

Arctic foxes Vulpes lagopus (L.) display a sharp 3- to 5-year fluctuation in population size where lemmings are their main prey. In areas devoid of lemmings, such as Iceland, they do not experience short-term fluctuations. This study focusses on the population dynamics of the arctic fox in Iceland and how it is shaped by its main prey populations. Hunting statistics from 1958-2003 show that the population size of the arctic fox was at a maximum in the 1950s, declined to a minimum in the 1970s, and increased steadily until 2003. Analysis of the arctic fox population size and their prey populations suggests that fox numbers were limited by rock ptarmigan numbers during the decline period. The recovery of the arctic fox population was traced mostly to an increase in goose populations, and favourable climatic conditions as reflected by the Subpolar Gyre. These results underscore the flexibility of a generalist predator and its responses to shifting food resources and climate changes.

Population differentiation in the red-legged kittiwake (Rissa brevirostris) as revealed by mitochondrial DNA

USGS Publications Warehouse

Patirana, A.; Hatcher, S.A.; Friesen, Vicki L.

2002-01-01

Population decline in red-legged kittiwakes (Rissa brevirostris) over recent decades has necessitated the collection of information on the distribution of genetic variation within and among colonies for implementation of suitable management policies. Here we present a preliminary study of the extent of genetic structuring and gene flow among the three principal breeding locations of red-legged kittiwakes using the hypervariable Domain I of the mitochondrial control region. Genetic variation was high relative to other species of seabirds, and was similar among locations. Analysis of molecular variance indicated that population genetic structure was statistically significant, and nested clade analysis suggested that kittiwakes breeding on Bering Island maybe genetically isolated from those elsewhere. However, phylogeographic structure was weak. Although this analysis involved only a single locus and a small number of samples, it suggests that red-legged kittiwakes probably constitute a single evolutionary significant unit; the possibility that they constitute two management units requires further investigation.

Analysis of Rare, Exonic Variation amongst Subjects with Autism Spectrum Disorders and Population Controls

PubMed Central

Liu, Li; Sabo, Aniko; Neale, Benjamin M.; Nagaswamy, Uma; Stevens, Christine; Lim, Elaine; Bodea, Corneliu A.; Muzny, Donna; Reid, Jeffrey G.; Banks, Eric; Coon, Hillary; DePristo, Mark; Dinh, Huyen; Fennel, Tim; Flannick, Jason; Gabriel, Stacey; Garimella, Kiran; Gross, Shannon; Hawes, Alicia; Lewis, Lora; Makarov, Vladimir; Maguire, Jared; Newsham, Irene; Poplin, Ryan; Ripke, Stephan; Shakir, Khalid; Samocha, Kaitlin E.; Wu, Yuanqing; Boerwinkle, Eric; Buxbaum, Joseph D.; Cook, Edwin H.; Devlin, Bernie; Schellenberg, Gerard D.; Sutcliffe, James S.; Daly, Mark J.; Gibbs, Richard A.; Roeder, Kathryn

2013-01-01

We report on results from whole-exome sequencing (WES) of 1,039 subjects diagnosed with autism spectrum disorders (ASD) and 870 controls selected from the NIMH repository to be of similar ancestry to cases. The WES data came from two centers using different methods to produce sequence and to call variants from it. Therefore, an initial goal was to ensure the distribution of rare variation was similar for data from different centers. This proved straightforward by filtering called variants by fraction of missing data, read depth, and balance of alternative to reference reads. Results were evaluated using seven samples sequenced at both centers and by results from the association study. Next we addressed how the data and/or results from the centers should be combined. Gene-based analyses of association was an obvious choice, but should statistics for association be combined across centers (meta-analysis) or should data be combined and then analyzed (mega-analysis)? Because of the nature of many gene-based tests, we showed by theory and simulations that mega-analysis has better power than meta-analysis. Finally, before analyzing the data for association, we explored the impact of population structure on rare variant analysis in these data. Like other recent studies, we found evidence that population structure can confound case-control studies by the clustering of rare variants in ancestry space; yet, unlike some recent studies, for these data we found that principal component-based analyses were sufficient to control for ancestry and produce test statistics with appropriate distributions. After using a variety of gene-based tests and both meta- and mega-analysis, we found no new risk genes for ASD in this sample. Our results suggest that standard gene-based tests will require much larger samples of cases and controls before being effective for gene discovery, even for a disorder like ASD. PMID:23593035

Phylogenetic Distribution of Leaf Spectra and Optically Derived Functional Traits in the American Oaks

NASA Astrophysics Data System (ADS)

Cavender-Bares, J.; Meireles, J. E.; Couture, J. J.; Kaproth, M.; Townsend, P. A.

2015-12-01

Detecting functional traits of species, genotypes and phylogenetic lineages is critical in monitoring functional biodiversity remotely. We examined the phylogenetic distribution of leaf spectra across the American Oaks for 35 species under greenhouse conditions as well as genetic variation in leaf spectra across Central American populations of a single species grown in common gardens in Honduras. We found significant phylogenetic signal in the leaf spectra (Blomberg's K > 1.0), indicating similarity in spectra among close relatives. Across species, full range leaf spectra were used in a Partial Least Squares Discriminant Analysis (PLS-DA) that allowed species calibration (kappa statistic = 0.55). Validation of the model used to detect species (kappa statistic = 0.4) indicated reasonably good detection of individual species within the same the genus. Among four populations from Belize, Costa Rica, Honduras, and Mexico within a single species (Quercus oleoides), leaf spectra were also able to differentiate populations. Ordination of population-level data using dissimilarities of predicted foliar traits, including leaf mass per area (LMA), lignin content, fiber content, chlorophyll a+b, and C:N ratio in genotypes in either watered or unwatered conditions showed significant differentiation among populations and treatments. These results provide promise for remote detection and differentiation of plant functional traits among plant phylogenetic lineages and genotypes, even among closely related populations and species.

Evaluating the performance of selection scans to detect selective sweeps in domestic dogs

PubMed Central

Schlamp, Florencia; van der Made, Julian; Stambler, Rebecca; Chesebrough, Lewis; Boyko, Adam R.; Messer, Philipp W.

2015-01-01

Selective breeding of dogs has resulted in repeated artificial selection on breed-specific morphological phenotypes. A number of quantitative trait loci associated with these phenotypes have been identified in genetic mapping studies. We analyzed the population genomic signatures observed around the causal mutations for 12 of these loci in 25 dog breeds, for which we genotyped 25 individuals in each breed. By measuring the population frequencies of the causal mutations in each breed, we identified those breeds in which specific mutations most likely experienced positive selection. These instances were then used as positive controls for assessing the performance of popular statistics to detect selection from population genomic data. We found that artificial selection during dog domestication has left characteristic signatures in the haplotype and nucleotide polymorphism patterns around selected loci that can be detected in the genotype data from a single population sample. However, the sensitivity and accuracy at which such signatures were detected varied widely between loci, the particular statistic used, and the choice of analysis parameters. We observed examples of both hard and soft selective sweeps and detected strong selective events that removed genetic diversity almost entirely over regions >10 Mbp. Our study demonstrates the power and limitations of selection scans in populations with high levels of linkage disequilibrium due to severe founder effects and recent population bottlenecks. PMID:26589239

Evaluating the performance of selection scans to detect selective sweeps in domestic dogs.

PubMed

Schlamp, Florencia; van der Made, Julian; Stambler, Rebecca; Chesebrough, Lewis; Boyko, Adam R; Messer, Philipp W

2016-01-01

Selective breeding of dogs has resulted in repeated artificial selection on breed-specific morphological phenotypes. A number of quantitative trait loci associated with these phenotypes have been identified in genetic mapping studies. We analysed the population genomic signatures observed around the causal mutations for 12 of these loci in 25 dog breeds, for which we genotyped 25 individuals in each breed. By measuring the population frequencies of the causal mutations in each breed, we identified those breeds in which specific mutations most likely experienced positive selection. These instances were then used as positive controls for assessing the performance of popular statistics to detect selection from population genomic data. We found that artificial selection during dog domestication has left characteristic signatures in the haplotype and nucleotide polymorphism patterns around selected loci that can be detected in the genotype data from a single population sample. However, the sensitivity and accuracy at which such signatures were detected varied widely between loci, the particular statistic used and the choice of analysis parameters. We observed examples of both hard and soft selective sweeps and detected strong selective events that removed genetic diversity almost entirely over regions >10 Mbp. Our study demonstrates the power and limitations of selection scans in populations with high levels of linkage disequilibrium due to severe founder effects and recent population bottlenecks. © 2015 John Wiley & Sons Ltd.

Anatomical shape analysis of the mandible in Caucasian and Chinese for the production of preformed mandible reconstruction plates.

PubMed

Metzger, Marc C; Vogel, Mathias; Hohlweg-Majert, Bettina; Mast, Hansjörg; Fan, Xianqun; Rüdell, Alexandra; Schlager, Stefan

2011-09-01

The purpose of this study was to evaluate and analyze statistical shapes of the outer mandible contour of Caucasian and Chinese people, offering data for the production of preformed mandible reconstruction plates. A CT-database of 925 Caucasians (male: n=463, female: n=462) and 960 Chinese (male: n=469, female: n=491) including scans of unaffected mandibles were used and imported into the 3D modeling software Voxim (IVS-Solutions, Chemnitz, Germany). Anatomical landmarks (n=22 points for both sides) were set using the 3D view along the outer contour of the mandible at the area where reconstruction plates are commonly located. We used morphometric methods for statistical shape analysis. We found statistical relevant differences between populations including a distinct discrimination given by the landmarks at the mandible. After generating a metric model this shape information which separated the populations appeared to be of no clinical relevance. The metric size information given by ramus length however provided a profound base for the production of standard reconstruction plates. Clustering by ramus length into three sizes and calculating means of these size-clusters seem to be a good solution for constructing preformed reconstruction plates that will fit a vast majority. Copyright © 2010 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Poisson-event-based analysis of cell proliferation.

PubMed

Summers, Huw D; Wills, John W; Brown, M Rowan; Rees, Paul

2015-05-01

A protocol for the assessment of cell proliferation dynamics is presented. This is based on the measurement of cell division events and their subsequent analysis using Poisson probability statistics. Detailed analysis of proliferation dynamics in heterogeneous populations requires single cell resolution within a time series analysis and so is technically demanding to implement. Here, we show that by focusing on the events during which cells undergo division rather than directly on the cells themselves a simplified image acquisition and analysis protocol can be followed, which maintains single cell resolution and reports on the key metrics of cell proliferation. The technique is demonstrated using a microscope with 1.3 μm spatial resolution to track mitotic events within A549 and BEAS-2B cell lines, over a period of up to 48 h. Automated image processing of the bright field images using standard algorithms within the ImageJ software toolkit yielded 87% accurate recording of the manually identified, temporal, and spatial positions of the mitotic event series. Analysis of the statistics of the interevent times (i.e., times between observed mitoses in a field of view) showed that cell division conformed to a nonhomogeneous Poisson process in which the rate of occurrence of mitotic events, λ exponentially increased over time and provided values of the mean inter mitotic time of 21.1 ± 1.2 hours for the A549 cells and 25.0 ± 1.1 h for the BEAS-2B cells. Comparison of the mitotic event series for the BEAS-2B cell line to that predicted by random Poisson statistics indicated that temporal synchronisation of the cell division process was occurring within 70% of the population and that this could be increased to 85% through serum starvation of the cell culture. © 2015 International Society for Advancement of Cytometry.

Population models for passerine birds: structure, parameterization, and analysis

USGS Publications Warehouse

Noon, B.R.; Sauer, J.R.; McCullough, D.R.; Barrett, R.H.

1992-01-01

Population models have great potential as management tools, as they use infonnation about the life history of a species to summarize estimates of fecundity and survival into a description of population change. Models provide a framework for projecting future populations, determining the effects of management decisions on future population dynamics, evaluating extinction probabilities, and addressing a variety of questions of ecological and evolutionary interest. Even when insufficient information exists to allow complete identification of the model, the modelling procedure is useful because it forces the investigator to consider the life history of the species when determining what parameters should be estimated from field studies and provides a context for evaluating the relative importance of demographic parameters. Models have been little used in the study of the population dynamics of passerine birds because of: (1) widespread misunderstandings of the model structures and parameterizations, (2) a lack of knowledge of life histories of many species, (3) difficulties in obtaining statistically reliable estimates of demographic parameters for most passerine species, and (4) confusion about functional relationships among demographic parameters. As a result, studies of passerine demography are often designed inappropriately and fail to provide essential data. We review appropriate models for passerine bird populations and illustrate their possible uses in evaluating the effects of management or other environmental influences on population dynamics. We identify environmental influences on population dynamics. We identify parameters that must be estimated from field data, briefly review existing statistical methods for obtaining valid estimates, and evaluate the present status of knowledge of these parameters.

Probability bounds analysis for nonlinear population ecology models.

PubMed

Enszer, Joshua A; Andrei Măceș, D; Stadtherr, Mark A

2015-09-01

Mathematical models in population ecology often involve parameters that are empirically determined and inherently uncertain, with probability distributions for the uncertainties not known precisely. Propagating such imprecise uncertainties rigorously through a model to determine their effect on model outputs can be a challenging problem. We illustrate here a method for the direct propagation of uncertainties represented by probability bounds though nonlinear, continuous-time, dynamic models in population ecology. This makes it possible to determine rigorous bounds on the probability that some specified outcome for a population is achieved, which can be a core problem in ecosystem modeling for risk assessment and management. Results can be obtained at a computational cost that is considerably less than that required by statistical sampling methods such as Monte Carlo analysis. The method is demonstrated using three example systems, with focus on a model of an experimental aquatic food web subject to the effects of contamination by ionic liquids, a new class of potentially important industrial chemicals. Copyright © 2015. Published by Elsevier Inc.

Diversity and association of phenotypic and metabolomic traits in the close model grasses Brachypodium distachyon, B. stacei and B. hybridum

PubMed Central

López-Álvarez, Diana; Zubair, Hassan; Beckmann, Manfred; Draper, John

2017-01-01

Abstract Background and Aims Morphological traits in combination with metabolite fingerprinting were used to investigate inter- and intraspecies diversity within the model annual grasses Brachypodium distachyon, Brachypodium stacei and Brachypodium hybridum. Methods Phenotypic variation of 15 morphological characters and 2219 nominal mass (m/z) signals generated using flow infusion electrospray ionization–mass spectrometry (FIE–MS) were evaluated in individuals from a total of 174 wild populations and six inbred lines, and 12 lines, of the three species, respectively. Basic statistics and multivariate principal component analysis and discriminant analysis were used to differentiate inter- and intraspecific variability of the two types of variable, and their association was assayed with the rcorr function. Key Results Basic statistics and analysis of variance detected eight phenotypic characters [(stomata) leaf guard cell length, pollen grain length, (plant) height, second leaf width, inflorescence length, number of spikelets per inflorescence, lemma length, awn length] and 434 tentatively annotated metabolite signals that significantly discriminated the three species. Three phenotypic traits (pollen grain length, spikelet length, number of flowers per inflorescence) might be genetically fixed. The three species showed different metabolomic profiles. Discriminant analysis significantly discriminated the three taxa with both morphometric and metabolome traits and the intraspecific phenotypic diversity within B. distachyon and B. stacei. The populations of B. hybridum were considerably less differentiated. Conclusions Highly explanatory metabolite signals together with morphological characters revealed concordant patterns of differentiation of the three taxa. Intraspecific phenotypic diversity was observed between northern and southern Iberian populations of B. distachyon and between eastern Mediterranean/south-western Asian and western Mediterranean populations of B. stacei. Significant association was found for pollen grain length and lemma length and ten and six metabolomic signals, respectively. These results would guide the selection of new germplasm lines of the three model grasses in ongoing genome-wide association studies. PMID:28040672

Digital Image Analysis of Yeast Single Cells Growing in Two Different Oxygen Concentrations to Analyze the Population Growth and to Assist Individual-Based Modeling.

PubMed

Ginovart, Marta; Carbó, Rosa; Blanco, Mónica; Portell, Xavier

2017-01-01

Nowadays control of the growth of Saccharomyces to obtain biomass or cellular wall components is crucial for specific industrial applications. The general aim of this contribution is to deal with experimental data obtained from yeast cells and from yeast cultures to attempt the integration of the two levels of information, individual and population, to progress in the control of yeast biotechnological processes by means of the overall analysis of this set of experimental data, and to assist in the improvement of an individual-based model, namely, INDISIM- Saccha . Populations of S. cerevisiae growing in liquid batch culture, in aerobic and microaerophilic conditions, were studied. A set of digital images was taken during the population growth, and a protocol for the treatment and analyses of the images obtained was established. The piecewise linear model of Buchanan was adjusted to the temporal evolutions of the yeast populations to determine the kinetic parameters and changes of growth phases. In parallel, for all the yeast cells analyzed, values of direct morphological parameters, such as area, perimeter, major diameter, minor diameter, and derived ones, such as circularity and elongation, were obtained. Graphical and numerical methods from descriptive statistics were applied to these data to characterize the growth phases and the budding state of the yeast cells in both experimental conditions, and inferential statistical methods were used to compare the diverse groups of data achieved. Oxidative metabolism of yeast in a medium with oxygen available and low initial sugar concentration can be taken into account in order to obtain a greater number of cells or larger cells. Morphological parameters were analyzed statistically to identify which were the most useful for the discrimination of the different states, according to budding and/or growth phase, in aerobic and microaerophilic conditions. The use of the experimental data for subsequent modeling work was then discussed and compared to simulation results generated with INDISIM- Saccha , which allowed us to advance in the development of this yeast model, and illustrated the utility of data at different levels of observation and the needs and logic behind the development of a microbial individual-based model.

Accuracy of metric sex analysis of skeletal remains using Fordisc based on a recent skull collection.

PubMed

Ramsthaler, F; Kreutz, K; Verhoff, M A

2007-11-01

It has been generally accepted in skeletal sex determination that the use of metric methods is limited due to the population dependence of the multivariate algorithms. The aim of the study was to verify the applicability of software-based sex estimations outside the reference population group for which discriminant equations have been developed. We examined 98 skulls from recent forensic cases of known age, sex, and Caucasian ancestry from cranium collections in Frankfurt and Mainz (Germany) to determine the accuracy of sex determination using the statistical software solution Fordisc which derives its database and functions from the US American Forensic Database. In a comparison between metric analysis using Fordisc and morphological determination of sex, average accuracy for both sexes was 86 vs 94%, respectively, and males were identified more accurately than females. The ratio of the true test result rate to the false test result rate was not statistically different for the two methodological approaches at a significance level of 0.05 but was statistically different at a level of 0.10 (p=0.06). Possible explanations for this difference comprise different ancestry, age distribution, and socio-economic status compared to the Fordisc reference sample. It is likely that a discriminant function analysis on the basis of more similar European reference samples will lead to more valid and reliable sexing results. The use of Fordisc as a single method for the estimation of sex of recent skeletal remains in Europe cannot be recommended without additional morphological assessment and without a built-in software update based on modern European reference samples.

Microcomputer package for statistical analysis of microbial populations.

PubMed

Lacroix, J M; Lavoie, M C

1987-11-01

We have developed a Pascal system to compare microbial populations from different ecological sites using microcomputers. The values calculated are: the coverage value and its standard error, the minimum similarity and the geometric similarity between two biological samples, and the Lambda test consisting of calculating the ratio of the mean similarity between two subsets by the mean similarity within subsets. This system is written for Apple II, IBM or compatible computers, but it can work for any computer which can use CP/M, if the programs are recompiled for such a system.

Patient Populations, Clinical Associations, and System Efficiency in Healthcare Delivery System

NASA Astrophysics Data System (ADS)

Liu, Yazhuo

The efforts to improve health care delivery usually involve studies and analysis of patient populations and healthcare systems. In this dissertation, I present the research conducted in the following areas: identifying patient groups, improving treatments for specific conditions by using statistical as well as data mining techniques, and developing new operation research models to increase system efficiency from the health institutes' perspective. The results provide better understanding of high risk patient groups, more accuracy in detecting disease' correlations and practical scheduling tools that consider uncertain operation durations and real-life constraints.

STR data for 15 autosomal STR markers from Paraná (Southern Brazil).

PubMed

Alves, Hemerson B; Leite, Fábio P N; Sotomaior, Vanessa S; Rueda, Fábio F; Silva, Rosane; Moura-Neto, Rodrigo S

2014-03-01

Allelic frequencies for 15 STR autosomal loci, using AmpFℓSTR® Identifiler™, forensic, and statistical parameters were calculated. All loci reached the Hardy-Weinberg equilibrium. The combined power of discrimination and mean power of exclusion were 0.999999999999999999 and 0.9999993, respectively. The MDS plot and NJ tree analysis, generated by FST matrix, corroborated the notion of the origins of the Paraná population as mainly European-derived. The combination of these 15 STR loci represents a powerful strategy for individual identification and parentage analyses for the Paraná population.

A Systems Analysis View of the Vietnam War 1965-1972. Volume 9. Population Security

DTIC Science & Technology

1975-02-01

CONPIDENTAL- DAA JJ* t I fe’. 18 CONFIDIBNITPALu3 C *’• SOUTH VIETNAM AMU STATUS VC cONUOU HAMMET I (I :I *, . ,A S~CONIDENTIAL GVN WRAL POMUITI0N CONTROL...ce they were not A-B hamlets at the beginning or end of the year. TABLE 2 A-B HAN BALMZ SHEET F(IC0R IWL RAWD HAMMET Pattern Types No. Population...is statistically insignificant in this equation . High kill ratios are associated with periods of high VC/NVA activity, so this model is consistent

A Dasymetric-Based Monte Carlo Simulation Approach to the Probabilistic Analysis of Spatial Variables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morton, April M; Piburn, Jesse O; McManamay, Ryan A

2017-01-01

Monte Carlo simulation is a popular numerical experimentation technique used in a range of scientific fields to obtain the statistics of unknown random output variables. Despite its widespread applicability, it can be difficult to infer required input probability distributions when they are related to population counts unknown at desired spatial resolutions. To overcome this challenge, we propose a framework that uses a dasymetric model to infer the probability distributions needed for a specific class of Monte Carlo simulations which depend on population counts.

Are Statisticians Cold-Blooded Bosses? A New Perspective on the "Old" Concept of Statistical Population

ERIC Educational Resources Information Center

Lu, Yonggang; Henning, Kevin S. S.

2013-01-01

Spurred by recent writings regarding statistical pragmatism, we propose a simple, practical approach to introducing students to a new style of statistical thinking that models nature through the lens of data-generating processes, not populations. (Contains 5 figures.)

Mild cognitive impairment and fMRI studies of brain functional connectivity: the state of the art

PubMed Central

Farràs-Permanyer, Laia; Guàrdia-Olmos, Joan; Peró-Cebollero, Maribel

2015-01-01

In the last 15 years, many articles have studied brain connectivity in Mild Cognitive Impairment patients with fMRI techniques, seemingly using different connectivity statistical models in each investigation to identify complex connectivity structures so as to recognize typical behavior in this type of patient. This diversity in statistical approaches may cause problems in results comparison. This paper seeks to describe how researchers approached the study of brain connectivity in MCI patients using fMRI techniques from 2002 to 2014. The focus is on the statistical analysis proposed by each research group in reference to the limitations and possibilities of those techniques to identify some recommendations to improve the study of functional connectivity. The included articles came from a search of Web of Science and PsycINFO using the following keywords: f MRI, MCI, and functional connectivity. Eighty-one papers were found, but two of them were discarded because of the lack of statistical analysis. Accordingly, 79 articles were included in this review. We summarized some parts of the articles, including the goal of every investigation, the cognitive paradigm and methods used, brain regions involved, use of ROI analysis and statistical analysis, emphasizing on the connectivity estimation model used in each investigation. The present analysis allowed us to confirm the remarkable variability of the statistical analysis methods found. Additionally, the study of brain connectivity in this type of population is not providing, at the moment, any significant information or results related to clinical aspects relevant for prediction and treatment. We propose to follow guidelines for publishing fMRI data that would be a good solution to the problem of study replication. The latter aspect could be important for future publications because a higher homogeneity would benefit the comparison between publications and the generalization of results. PMID:26300802

Impact of human population history on distributions of individual-level genetic distance

PubMed Central

2005-01-01

Summaries of human genomic variation shed light on human evolution and provide a framework for biomedical research. Variation is often summarised in terms of one or a few statistics (eg FST and gene diversity). Now that multilocus genotypes for hundreds of autosomal loci are available for thousands of individuals, new approaches are applicable. Recently, trees of individuals and other clustering approaches have demonstrated the power of an individual-focused analysis. We propose analysing the distributions of genetic distances between individuals. Each distribution, or common ancestry profile (CAP), is unique to an individual, and does not require a priori assignment of individuals to populations. Here, we consider a range of models of population history and, using coalescent simulation, reveal the potential insights gained from a set of CAPs. Information lies in the shapes of individual profiles -- sometimes captured by variance of individual CAPs -- and the variation across profiles. Analysis of short tandem repeat genotype data for over 1,000 individuals from 52 populations is consistent with dramatic differences in population histories across human groups. PMID:15814064

Stochastic seasonality and nonlinear density-dependent factors regulate population size in an African rodent

USGS Publications Warehouse

Leirs, H.; Stenseth, N.C.; Nichols, J.D.; Hines, J.E.; Verhagen, R.; Verheyen, W.

1997-01-01

Ecology has long been troubled by the controversy over how populations are regulated. Some ecologists focus on the role of environmental effects, whereas others argue that density-dependent feedback mechanisms are central. The relative importance of both processes is still hotly debated, but clear examples of both processes acting in the same population are rare. Keyfactor analysis (regression of population changes on possible causal factors) and time-series analysis are often used to investigate the presence of density dependence, but such approaches may be biased and provide no information on actual demographic rates. Here we report on both density-dependent and density-independent effects in a murid rodent pest species, the multimammate rat Mastomys natalensis (Smith, 1834), using statistical capture-recapture models. Both effects occur simultaneously, but we also demonstrate that they do not affect all demographic rates in the same way. We have incorporated the obtained estimates of demographic rates in a population dynamics model and show that the observed dynamics are affected by stabilizing nonlinear density-dependent components coupled with strong deterministic and stochastic seasonal components.

Human mtDNA hypervariable regions, HVR I and II, hint at deep common maternal founder and subsequent maternal gene flow in Indian population groups.

PubMed

Sharma, Swarkar; Saha, Anjana; Rai, Ekta; Bhat, Audesh; Bamezai, Ramesh

2005-01-01

We have analysed the hypervariable regions (HVR I and II) of human mitochondrial DNA (mtDNA) in individuals from Uttar Pradesh (UP), Bihar (BI) and Punjab (PUNJ), belonging to the Indo-European linguistic group, and from South India (SI), that have their linguistic roots in Dravidian language. Our analysis revealed the presence of known and novel mutations in both hypervariable regions in the studied population groups. Median joining network analyses based on mtDNA showed extensive overlap in mtDNA lineages despite the extensive cultural and linguistic diversity. MDS plot analysis based on Fst distances suggested increased maternal genetic proximity for the studied population groups compared with other world populations. Mismatch distribution curves, respective neighbour joining trees and other statistical analyses showed that there were significant expansions. The study revealed an ancient common ancestry for the studied population groups, most probably through common founder female lineage(s), and also indicated that human migrations occurred (maybe across and within the Indian subcontinent) even after the initial phase of female migration to India.

Identification of cognitive and non-cognitive predictive variables related to attrition in baccalaureate nursing education programs in Mississippi

NASA Astrophysics Data System (ADS)

Hayes, Catherine

2005-07-01

This study sought to identify a variable or variables predictive of attrition among baccalaureate nursing students. The study was quantitative in design and multivariate correlational statistics and discriminant statistical analysis were used to identify a model for prediction of attrition. The analysis then weighted variables according to their predictive value to determine the most parsimonious model with the greatest predictive value. Three public university nursing education programs in Mississippi offering a Bachelors Degree in Nursing were selected for the study. The population consisted of students accepted and enrolled in these three programs for the years 2001 and 2002 and graduating in the years 2003 and 2004 (N = 195). The categorical dependent variable was attrition (includes academic failure or withdrawal) from the program of nursing education. The ten independent variables selected for the study and considered to have possible predictive value were: Grade Point Average for Pre-requisite Course Work; ACT Composite Score, ACT Reading Subscore, and ACT Mathematics Subscore; Letter Grades in the Courses: Anatomy & Physiology and Lab I, Algebra I, English I (101), Chemistry & Lab I, and Microbiology & Lab I; and Number of Institutions Attended (Universities, Colleges, Junior Colleges or Community Colleges). Descriptive analysis was performed and the means of each of the ten independent variables was compared for students who attrited and those who were retained in the population. The discriminant statistical analysis performed created a matrix using the ten variable model that was able to correctly predicted attrition in the study's population in 77.6% of the cases. Variables were then combined and recombined to produce the most efficient and parsimonious model for prediction. A six variable model resulted which weighted each variable according to predictive value: GPA for Prerequisite Coursework, ACT Composite, English I, Chemistry & Lab I, Microbiology & Lab I, and Number of Institutions Attended. Results of the study indicate that it is possible to predict attrition among students enrolled in baccalaureate nursing education programs and that additional investigation on the subject is warranted.

Mars Pathfinder Near-Field Rock Distribution Re-Evaluation

NASA Technical Reports Server (NTRS)

Haldemann, A. F. C.; Golombek, M. P.

2003-01-01

We have completed analysis of a new near-field rock count at the Mars Pathfinder landing site and determined that the previously published rock count suggesting 16% cumulative fractional area (CFA) covered by rocks is incorrect. The earlier value is not so much wrong (our new CFA is 20%), as right for the wrong reason: both the old and the new CFA's are consistent with remote sensing data, however the earlier determination incorrectly calculated rock coverage using apparent width rather than average diameter. Here we present details of the new rock database and the new statistics, as well as the importance of using rock average diameter for rock population statistics. The changes to the near-field data do not affect the far-field rock statistics.

Quasi-experimental study designs series-paper 10: synthesizing evidence for effects collected from quasi-experimental studies presents surmountable challenges.

PubMed

Becker, Betsy Jane; Aloe, Ariel M; Duvendack, Maren; Stanley, T D; Valentine, Jeffrey C; Fretheim, Atle; Tugwell, Peter

2017-09-01

To outline issues of importance to analytic approaches to the synthesis of quasi-experiments (QEs) and to provide a statistical model for use in analysis. We drew on studies of statistics, epidemiology, and social-science methodology to outline methods for synthesis of QE studies. The design and conduct of QEs, effect sizes from QEs, and moderator variables for the analysis of those effect sizes were discussed. Biases, confounding, design complexities, and comparisons across designs offer serious challenges to syntheses of QEs. Key components of meta-analyses of QEs were identified, including the aspects of QE study design to be coded and analyzed. Of utmost importance are the design and statistical controls implemented in the QEs. Such controls and any potential sources of bias and confounding must be modeled in analyses, along with aspects of the interventions and populations studied. Because of such controls, effect sizes from QEs are more complex than those from randomized experiments. A statistical meta-regression model that incorporates important features of the QEs under review was presented. Meta-analyses of QEs provide particular challenges, but thorough coding of intervention characteristics and study methods, along with careful analysis, should allow for sound inferences. Copyright © 2017 Elsevier Inc. All rights reserved.

Attenuation of Storm Surge Flooding By Wetlands in the Chesapeake Bay: An Integrated Geospatial Framework Evaluating Impacts to Critical Infrastructure

NASA Astrophysics Data System (ADS)

Khalid, A.; Haddad, J.; Lawler, S.; Ferreira, C.

2014-12-01

Areas along the Chesapeake Bay and its tributaries are extremely vulnerable to hurricane flooding, as evidenced by the costly effects and severe impacts of recent storms along the Virginia coast, such as Hurricane Isabel in 2003 and Hurricane Sandy in 2012. Coastal wetlands, in addition to their ecological importance, are expected to mitigate the impact of storm surge by acting as a natural protection against hurricane flooding. Quantifying such interactions helps to provide a sound scientific basis to support planning and decision making. Using storm surge flooding from various historical hurricanes, simulated using a coupled hydrodynamic wave model (ADCIRC-SWAN), we propose an integrated framework yielding a geospatial identification of the capacity of Chesapeake Bay wetlands to protect critical infrastructure. Spatial identification of Chesapeake Bay wetlands is derived from the National Wetlands Inventory (NWI), National Land Cover Database (NLCD), and the Coastal Change Analysis Program (C-CAP). Inventories of population and critical infrastructure are extracted from US Census block data and FEMA's HAZUS-Multi Hazard geodatabase. Geospatial and statistical analyses are carried out to develop a relationship between wetland land cover, hurricane flooding, population and infrastructure vulnerability. These analyses result in the identification and quantification of populations and infrastructure in flooded areas that lie within a reasonable buffer surrounding the identified wetlands. Our analysis thus produces a spatial perspective on the potential for wetlands to attenuate hurricane flood impacts in critical areas. Statistical analysis will support hypothesis testing to evaluate the benefits of wetlands from a flooding and storm-surge attenuation perspective. Results from geospatial analysis are used to identify where interactions with critical infrastructure are relevant in the Chesapeake Bay.

Green tea and liver cancer risk: A meta-analysis of prospective cohort studies in Asian populations.

PubMed

Huang, Ya-Qing; Lu, Xin; Min, Han; Wu, Qian-Qian; Shi, Xiao-Ting; Bian, Kang-Qi; Zou, Xiao-Ping

2016-01-01

The aim of this meta-analysis was to investigate whether an association existed between green tea consumption and the risk for liver cancer in prospective cohort studies in Asian populations. Relevant studies were identified by searching PubMed, EMBASE, ISI Web of Science, and the Chinese Bio-medicine Database published before April 2015. Study-specific risk estimates for the highest versus non- or lowest and increment of daily cup of green tea consumption levels were combined based on fixed- or random-effects models. STATA 11.0 (Stata Corporation, College Station, TX, USA) software was used for statistical analysis. Nine prospective cohort articles involving 465,274 participants and 3694 cases of liver cancer from China, Japan, and Singapore were included. The summary relative risk (RR) indicated a significant association between the highest green tea consumption and reduced risk for liver cancer (summary RR, 0.88; 95% confidence interval [CI], 0.81-0.97). However, no statistically significant association was observed when analyzing daily consumption of one cup (summary RR, 0.97; 95% CI, 0.95-1.00). When stratified by sex, the protective effect of green tea consumption on risk for liver cancer was observed only in the group of women (summary RR, 0.78; 95% CI, 0.64-0.96), but not in men (summary RR, 0.89; 95% CI, 0.79-1.00). The present analysis indicated the preventive effects of green tea intake on the risk for liver cancer in female Asian populations. However, additional studies are needed to make a convincing case for this association. Copyright © 2016 Elsevier Inc. All rights reserved.

Statistical Report of Central Nervous System Tumors Histologically Diagnosed in the Sichuan Province of China from 2008 to 2013: A West China Glioma Center Report.

PubMed

Wang, Xiang; Chen, Jin-Xiu; Zhou, Qiao; Liu, Yan-Hui; Mao, Qing; You, Chao; Chen, Ni; Xiong, Li; Duan, Jie; Liu, Liang

2016-12-01

Sichuan is a province in the west of China with a population of 81.4 million. This is the first statistical report of central nervous system (CNS) tumors surgically treated and histologically diagnosed in a large Chinese population. All the patient data were obtained from 86 medical facilities, which covered the Sichuan province population. Data from patients who underwent surgery between 2008 and 2013 and corresponding histology samples were re-reviewed in the major pathology centers. All the CNS tumors were categorized according to International Classification of Diseases (ICD)-10 and ICD-O-3 classifications and reviewed manually. The tumor distribution was analyzed and stratified by gender, age, race, and tumor sites. Tumors in some ethnic minorities, such as the Tibetan people, also were analyzed. The final analytic dataset included 35,496 records. The top four histologic tumors were meningioma (28.51 %), pituitary adenoma (15.00 %), nerve sheath (13.77 %), and glioblastoma (11.82 %). There was a dramatically high incidence of malignant tumor in males. The median age at diagnosis ranged from 13 years (pineal region tumors) to 56 years (metastatic brain tumors). Most of the tumors in the insular lobe or cerebellum were low grade, whereas those in the thalamus or basal ganglia were likely to be high grade. The incidence of malignant tumors or high-grade gliomas in the Tibetans was significantly lower than in the Chinese Han population. This report is a preliminary statistical analysis of brain and spinal tumors in a large Chinese population and may serve as a useful resource for clinicians, researchers, and patients' families.

Statistical and population genetics issues of two Hungarian datasets from the aspect of DNA evidence interpretation.

PubMed

Szabolcsi, Zoltán; Farkas, Zsuzsa; Borbély, Andrea; Bárány, Gusztáv; Varga, Dániel; Heinrich, Attila; Völgyi, Antónia; Pamjav, Horolma

2015-11-01

When the DNA profile from a crime-scene matches that of a suspect, the weight of DNA evidence depends on the unbiased estimation of the match probability of the profiles. For this reason, it is required to establish and expand the databases that reflect the actual allele frequencies in the population applied. 21,473 complete DNA profiles from Databank samples were used to establish the allele frequency database to represent the population of Hungarian suspects. We used fifteen STR loci (PowerPlex ESI16) including five, new ESS loci. The aim was to calculate the statistical, forensic efficiency parameters for the Databank samples and compare the newly detected data to the earlier report. The population substructure caused by relatedness may influence the frequency of profiles estimated. As our Databank profiles were considered non-random samples, possible relationships between the suspects can be assumed. Therefore, population inbreeding effect was estimated using the FIS calculation. The overall inbreeding parameter was found to be 0.0106. Furthermore, we tested the impact of the two allele frequency datasets on 101 randomly chosen STR profiles, including full and partial profiles. The 95% confidence interval estimates for the profile frequencies (pM) resulted in a tighter range when we used the new dataset compared to the previously published ones. We found that the FIS had less effect on frequency values in the 21,473 samples than the application of minimum allele frequency. No genetic substructure was detected by STRUCTURE analysis. Due to the low level of inbreeding effect and the high number of samples, the new dataset provides unbiased and precise estimates of LR for statistical interpretation of forensic casework and allows us to use lower allele frequencies. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Current genetic methodologies in the identification of disaster victims and in forensic analysis.

PubMed

Ziętkiewicz, Ewa; Witt, Magdalena; Daca, Patrycja; Zebracka-Gala, Jadwiga; Goniewicz, Mariusz; Jarząb, Barbara; Witt, Michał

2012-02-01

This review presents the basic problems and currently available molecular techniques used for genetic profiling in disaster victim identification (DVI). The environmental conditions of a mass disaster often result in severe fragmentation, decomposition and intermixing of the remains of victims. In such cases, traditional identification based on the anthropological and physical characteristics of the victims is frequently inconclusive. This is the reason why DNA profiling became the gold standard for victim identification in mass-casualty incidents (MCIs) or any forensic cases where human remains are highly fragmented and/or degraded beyond recognition. The review provides general information about the sources of genetic material for DNA profiling, the genetic markers routinely used during genetic profiling (STR markers, mtDNA and single-nucleotide polymorphisms [SNP]) and the basic statistical approaches used in DNA-based disaster victim identification. Automated technological platforms that allow the simultaneous analysis of a multitude of genetic markers used in genetic identification (oligonucleotide microarray techniques and next-generation sequencing) are also presented. Forensic and population databases containing information on human variability, routinely used for statistical analyses, are discussed. The final part of this review is focused on recent developments, which offer particularly promising tools for forensic applications (mRNA analysis, transcriptome variation in individuals/populations and genetic profiling of specific cells separated from mixtures).

Palatal rugae pattern: An aid for sex identification

PubMed Central

Gadicherla, Prahlad; Saini, Divya; Bhaskar, Milana

2017-01-01

Background: Palatal rugoscopy, or palatoscopy, is the process by which human identification can be obtained by inspecting the transverse palatal rugae inside the mouth. Aim: The aim of the study is to investigate the potential of using palatal rugae as an aid for sex identification in Bengaluru population. Materials and Methods: One hundred plaster casts equally distributed between males and females belonging to age range of 4–16 years were examined for different rugae patterns. Thomas and Kotze classification was adopted for identification of these rugae patterns. Statistical Analysis: The data obtained were subjected to discriminant function analysis to determine the applicability of palatal rugae pattern as an aid for sex identification. Results: Difference in unification patterns among males and females was found to be statistically significant. No significant difference was found between males and females in terms of number of rugae. Overall, wavy and curvy were the most predominant type of rugae seen. Discriminant function analysis enabled sex identification with an accuracy of 80%. Conclusion: This preliminary study undertaken showed the existence of a distinct pattern of distribution of palatal rugae between males and females of Bengaluru population. This study opens scope for further research with a larger sample size to establish palatal rugae as a valuable tool for sex identification for forensic purposes. PMID:28584485

Epidemics in Ming and Qing China: Impacts of changes of climate and economic well-being.

PubMed

Pei, Qing; Zhang, David D; Li, Guodong; Winterhalder, Bruce; Lee, Harry F

2015-07-01

We investigated the mechanism of epidemics with the impacts of climate change and socio-economic fluctuations in the Ming and Qing Dynasties in China (AD 1368-1901). Using long-term and high-quality datasets, this study is the first quantitative research that verifies the 'climate change → economy → epidemics' mechanism in historical China by statistical methods that include correlation analysis, Granger causality analysis, ARX, and Poisson-ARX modeling. The analysis provides the evidences that climate change could only fundamentally lead to the epidemics spread and occurrence, but the depressed economic well-being is the direct trigger of epidemics spread and occurrence at the national and long term scale in historical China. Moreover, statistical modeling shows that economic well-being is more important than population pressure in the mechanism of epidemics. However, population pressure remains a key element in determining the social vulnerability of the epidemics occurrence under climate change. Notably, the findings not only support adaptation theories but also enhance our confidence to address climatic shocks if economic buffering capacity can be promoted steadily. The findings can be a basis for scientists and policymakers in addressing global and regional environmental changes. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Future of Small- and Medium-Sized Communities in the Prairie Region.

ERIC Educational Resources Information Center

Wellar, Barry S., Ed.

Four papers are featured. The first is a statistical overview and analysis of past, present and future happenings to small communities in the Region; it focuses on two indicators: (1) population growth or declining community class size and, (2) the changing distribution of commercial outlets by community class size. The other three papers report…

Women of the World: Asia and the Pacific.

ERIC Educational Resources Information Center

Shah, Nasra M.

The fourth in a series of five handbooks designed to present and analyze statistical data on women in various regions of the world, this handbook focuses on women in 14 countries of Asia and the Pacific. Beginning with an overview of population distribution and changes in the region, the analysis continues with a description of women's literacy…

Women of the World: Latin America and the Caribbean.

ERIC Educational Resources Information Center

Chaney, Elsa M.

The first in a series of five handbooks designed to present and analyze statistical data on women in various regions of the world, this handbook focuses on women in 21 countries in Latin America and the Caribbean. Beginning with an overview of population characteristics of the regions, the analysis continues with a description of women's literacy…

A Robust New Method for Analzing Community Change and an Example using 83 years of Avian Response to Forest Succession

EPA Science Inventory

This manuscript describes a novel statistical analysis technique developed by the authors for use in combining survey data carried out under different field protocols. We apply the technique to 83 years of survey data on avian songbird populations in northern lower Michigan to de...

MEXICAN-AMERICAN STUDY PROJECT. ADVANCE REPORT 4, RESIDENTIAL SEGREGATION IN THE URBAN SOUTHWEST.

ERIC Educational Resources Information Center

MOORE, JOAN W.; AND OTHERS

THIS ADVANCE REPORT PRESENTS A STATISTICAL ANALYSIS OF THE DEGREE OF RESIDENTIAL SEGREGATION OF THE MEXICAN-AMERICAN AND NEGRO SUBPOPULATIONS FROM THE ANGLO SUBPOPULATIONS IN URBAN AREAS. ALL OF THE DATA WERE DRAWN FROM THE 1950 AND 1960 CENSUSES OF POPULATION AND HOUSING. FACTORS STUDIED INCLUDE URBANIZATION PATTERNS AND ORIGINS OF…

Fisher, Sir Ronald Aylmer (1890-1962)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Statistician, born in London, England. After studying astronomy using AIRY's manual on the Theory of Errors he became interested in statistics, and laid the foundation of randomization in experimental design, the analysis of variance and the use of data in estimating the properties of the parent population from which it was drawn. Invented the maximum likelihood method for estimating from random ...

Modeling Outcomes with Floor or Ceiling Effects: An Introduction to the Tobit Model

ERIC Educational Resources Information Center

McBee, Matthew

2010-01-01

In gifted education research, it is common for outcome variables to exhibit strong floor or ceiling effects due to insufficient range of measurement of many instruments when used with gifted populations. Common statistical methods (e.g., analysis of variance, linear regression) produce biased estimates when such effects are present. In practice,…

Autism Spectrum Disorder in Down Syndrome: Cluster Analysis of Aberrant Behaviour Checklist Data Supports Diagnosis

ERIC Educational Resources Information Center

Ji, N. Y.; Capone, G. T.; Kaufmann, W. E.

2011-01-01

Background: The diagnostic validity of autism spectrum disorder (ASD) based on Diagnostic and Statistical Manual of Mental Disorders (DSM) has been challenged in Down syndrome (DS), because of the high prevalence of cognitive impairments in this population. Therefore, we attempted to validate DSM-based diagnoses via an unbiased categorisation of…

The Disappeared Ones: Female Student Veterans at a Four-Year College

ERIC Educational Resources Information Center

Heitzman, Amy Claire; Somers, Patricia

2015-01-01

Since the end of the military draft in 1973, women have entered military service in greater numbers: Women currently account for 16 percent of active-duty service personnel; by 2035, they will account for 15 percent of the total veteran population (National Center for Veterans Analysis and Statistics 2011). The profile of female veterans differs…

Invisible Ink: An Analysis of Meaning Contained in Gender, Race, Performance, and Power Discourses

ERIC Educational Resources Information Center

Griggs, Susan A.

2012-01-01

The number of females in senior level leadership positions in higher education is substantially fewer than males. Yet female students in these same institutions represent over half the population (National Center for Educational Statistics, 2010). The leadership gender gap is a phenomenon that has undergone numerous studies in search of reasons…

Hunting statistics: what data for what use? An account of an international workshop

USGS Publications Warehouse

Nichols, J.D.; Lancia, R.A.; Lebreton, J.D.

2001-01-01

Hunting interacts with the underlying dynamics of game species in several different ways and is, at the same time, a source of valuable information not easily obtained from populations that are not subjected to hunting. Specific questions, including the sustainability of hunting activities, can be addressed using hunting statistics. Such investigations will frequently require that hunting statistics be combined with data from other sources of population-level information. Such reflections served as a basis for the meeting, ?Hunting Statistics: What Data for What Use,? held on January 15-18, 2001 in Saint-Benoist, France. We review here the 20 talks held during the workshop and the contribution of hunting statistics to our knowledge of the population dynamics of game species. Three specific topics (adaptive management, catch-effort models, and dynamics of exploited populations) were highlighted as important themes and are more extensively presented as boxes.

PLINK: A Tool Set for Whole-Genome Association and Population-Based Linkage Analyses

PubMed Central

Purcell, Shaun ; Neale, Benjamin ; Todd-Brown, Kathe ; Thomas, Lori ; Ferreira, Manuel A. R. ; Bender, David ; Maller, Julian ; Sklar, Pamela ; de Bakker, Paul I. W. ; Daly, Mark J. ; Sham, Pak C. 

2007-01-01

Whole-genome association studies (WGAS) bring new computational, as well as analytic, challenges to researchers. Many existing genetic-analysis tools are not designed to handle such large data sets in a convenient manner and do not necessarily exploit the new opportunities that whole-genome data bring. To address these issues, we developed PLINK, an open-source C/C++ WGAS tool set. With PLINK, large data sets comprising hundreds of thousands of markers genotyped for thousands of individuals can be rapidly manipulated and analyzed in their entirety. As well as providing tools to make the basic analytic steps computationally efficient, PLINK also supports some novel approaches to whole-genome data that take advantage of whole-genome coverage. We introduce PLINK and describe the five main domains of function: data management, summary statistics, population stratification, association analysis, and identity-by-descent estimation. In particular, we focus on the estimation and use of identity-by-state and identity-by-descent information in the context of population-based whole-genome studies. This information can be used to detect and correct for population stratification and to identify extended chromosomal segments that are shared identical by descent between very distantly related individuals. Analysis of the patterns of segmental sharing has the potential to map disease loci that contain multiple rare variants in a population-based linkage analysis. PMID:17701901

A simple method for purification of vestibular hair cells and non-sensory cells, and application for proteomic analysis.

PubMed

Herget, Meike; Scheibinger, Mirko; Guo, Zhaohua; Jan, Taha A; Adams, Christopher M; Cheng, Alan G; Heller, Stefan

2013-01-01

Mechanosensitive hair cells and supporting cells comprise the sensory epithelia of the inner ear. The paucity of both cell types has hampered molecular and cell biological studies, which often require large quantities of purified cells. Here, we report a strategy allowing the enrichment of relatively pure populations of vestibular hair cells and non-sensory cells including supporting cells. We utilized specific uptake of fluorescent styryl dyes for labeling of hair cells. Enzymatic isolation and flow cytometry was used to generate pure populations of sensory hair cells and non-sensory cells. We applied mass spectrometry to perform a qualitative high-resolution analysis of the proteomic makeup of both the hair cell and non-sensory cell populations. Our conservative analysis identified more than 600 proteins with a false discovery rate of <3% at the protein level and <1% at the peptide level. Analysis of proteins exclusively detected in either population revealed 64 proteins that were specific to hair cells and 103 proteins that were only detectable in non-sensory cells. Statistical analyses extended these groups by 53 proteins that are strongly upregulated in hair cells versus non-sensory cells and vice versa by 68 proteins. Our results demonstrate that enzymatic dissociation of styryl dye-labeled sensory hair cells and non-sensory cells is a valid method to generate pure enough cell populations for flow cytometry and subsequent molecular analyses.

From micro to mainframe. A practical approach to perinatal data processing.

PubMed

Yeh, S Y; Lincoln, T

1985-04-01

A new, practical approach to perinatal data processing for a large obstetric population is described. This was done with a microcomputer for data entry and a mainframe computer for data reduction. The Screen Oriented Data Access (SODA) program was used to generate the data entry form and to input data into the Apple II Plus computer. Data were stored on diskettes and transmitted through a modern and telephone line to the IBM 370/168 computer. The Statistical Analysis System (SAS) program was used for statistical analyses and report generations. This approach was found to be most practical, flexible, and economical.

Apes are intuitive statisticians.

PubMed

Rakoczy, Hannes; Clüver, Annette; Saucke, Liane; Stoffregen, Nicole; Gräbener, Alice; Migura, Judith; Call, Josep

2014-04-01

Inductive learning and reasoning, as we use it both in everyday life and in science, is characterized by flexible inferences based on statistical information: inferences from populations to samples and vice versa. Many forms of such statistical reasoning have been found to develop late in human ontogeny, depending on formal education and language, and to be fragile even in adults. New revolutionary research, however, suggests that even preverbal human infants make use of intuitive statistics. Here, we conducted the first investigation of such intuitive statistical reasoning with non-human primates. In a series of 7 experiments, Bonobos, Chimpanzees, Gorillas and Orangutans drew flexible statistical inferences from populations to samples. These inferences, furthermore, were truly based on statistical information regarding the relative frequency distributions in a population, and not on absolute frequencies. Intuitive statistics in its most basic form is thus an evolutionarily more ancient rather than a uniquely human capacity. Copyright © 2014 Elsevier B.V. All rights reserved.

Statistical Study of the Properties of Magnetosheath Lion Roars using MMS observations

NASA Astrophysics Data System (ADS)

Giagkiozis, S.; Wilson, L. B., III

2017-12-01

Intense whistler-mode waves of very short duration are frequently encountered in the magnetosheath. These emissions have been linked to mirror mode waves and the Earth's bow shock. They can efficiently transfer energy between different plasma populations. These electromagnetic waves are commonly referred to as Lion roars (LR), due to the sound generated when the signals are sonified. They are generally observed during dips of the magnetic field that are anti-correlated with increases of density. Using MMS data, we have identified more than 1750 individual LR burst intervals. Each emission was band-pass filtered and further split into >35,000 subintervals, for which the direction of propagation and the polarization were calculated. The analysis of subinterval properties provides a more accurate representation of their true nature than the more commonly used time- and frequency-averaged dynamic spectra analysis. The results of the statistical analysis of the wave properties will be presented.

Urban Transmission of American Cutaneous Leishmaniasis in Argentina: Spatial Analysis Study

PubMed Central

Gil, José F.; Nasser, Julio R.; Cajal, Silvana P.; Juarez, Marisa; Acosta, Norma; Cimino, Rubén O.; Diosque, Patricio; Krolewiecki, Alejandro J.

2010-01-01

We used kernel density and scan statistics to examine the spatial distribution of cases of pediatric and adult American cutaneous leishmaniasis in an urban disease-endemic area in Salta Province, Argentina. Spatial analysis was used for the whole population and stratified by women > 14 years of age (n = 159), men > 14 years of age (n = 667), and children < 15 years of age (n = 213). Although kernel density for adults encompassed nearly the entire city, distribution in children was most prevalent in the peripheral areas of the city. Scan statistic analysis for adult males, adult females, and children found 11, 2, and 8 clusters, respectively. Clusters for children had the highest odds ratios (P < 0.05) and were located in proximity of plantations and secondary vegetation. The data from this study provide further evidence of the potential urban transmission of American cutaneous leishmaniasis in northern Argentina. PMID:20207869

[Cardiovascular diseases in the population of industrial towns and environmental factors].

PubMed

Ibraeva, L K; Azhimetova, G N; Amanbekova, A U; Bakirova, R E

2015-01-01

To study the influence of environmental factors (EFs) on the development of cardiovascular diseases in the population of industrial towns of the Republic of Kazakhstan. The investigation covered an 18-59-year-old adult population who had been living in the urbanized areas of the Republic of Kazakhstan for at least 10 years, who worked in harmless conditions and were unregistered as having chronic diseases. At Stage 1, screening (a therapist's examination, blood general and immunological tests, and electrocardiography) was carried out for risk group persons who underwent in-depth clinical examination (blood biochemical test) at Stage 2. Multivariate statistical analysis has revealed that the development of hypertension is associated with the high concentration of sulfur dioxide in atmospheric air, copper in dust sediments, and zinc in soil and that of coronary heart disease (CHD) is related to the high levels of nitrogen dioxide in atmospheric air and zinc in dust sediments. Based on pathogenetic and statistical data and information available in the literature, hypertension and CHD are referred to as the diseases that may result from the influence of EFs.

Control entropy identifies differential changes in complexity of walking and running gait patterns with increasing speed in highly trained runners

NASA Astrophysics Data System (ADS)

McGregor, Stephen J.; Busa, Michael A.; Skufca, Joseph; Yaggie, James A.; Bollt, Erik M.

2009-06-01

Regularity statistics have been previously applied to walking gait measures in the hope of gaining insight into the complexity of gait under different conditions and in different populations. Traditional regularity statistics are subject to the requirement of stationarity, a limitation for examining changes in complexity under dynamic conditions such as exhaustive exercise. Using a novel measure, control entropy (CE), applied to triaxial continuous accelerometry, we report changes in complexity of walking and running during increasing speeds up to exhaustion in highly trained runners. We further apply Karhunen-Loeve analysis in a new and novel way to the patterns of CE responses in each of the three axes to identify dominant modes of CE responses in the vertical, mediolateral, and anterior/posterior planes. The differential CE responses observed between the different axes in this select population provide insight into the constraints of walking and running in those who may have optimized locomotion. Future comparisons between athletes, healthy untrained, and clinical populations using this approach may help elucidate differences between optimized and diseased locomotor control.

Hierarchical modeling and inference in ecology: The analysis of data from populations, metapopulations and communities

USGS Publications Warehouse

Royle, J. Andrew; Dorazio, Robert M.

2008-01-01

A guide to data collection, modeling and inference strategies for biological survey data using Bayesian and classical statistical methods. This book describes a general and flexible framework for modeling and inference in ecological systems based on hierarchical models, with a strict focus on the use of probability models and parametric inference. Hierarchical models represent a paradigm shift in the application of statistics to ecological inference problems because they combine explicit models of ecological system structure or dynamics with models of how ecological systems are observed. The principles of hierarchical modeling are developed and applied to problems in population, metapopulation, community, and metacommunity systems. The book provides the first synthetic treatment of many recent methodological advances in ecological modeling and unifies disparate methods and procedures. The authors apply principles of hierarchical modeling to ecological problems, including * occurrence or occupancy models for estimating species distribution * abundance models based on many sampling protocols, including distance sampling * capture-recapture models with individual effects * spatial capture-recapture models based on camera trapping and related methods * population and metapopulation dynamic models * models of biodiversity, community structure and dynamics.

[Path analysis of lifestyle habits to the metabolic syndrome].

PubMed

Zhu, Zhen-xin; Zhang, Cheng-qi; Tang, Fang; Song, Xin-hong; Xue, Fu-zhong

2013-04-01

To evaluate the relationship between lifestyle habits and the components of metabolic syndrome (MS). Based on the routine health check-up system in a certain Center for Health Management of Shandong Province, a longitudinal surveillance health check-up cohort from 2005 to 2010 was set up. There were 13 225 urban workers in Jinan included in the analysis. The content of the survey included demographic information, medical history, lifestyle habits, body mass index (BMI) and the level of blood pressure, fasting blood-glucose, and blood lipid, etc. The distribution of BMI, blood pressure, fasting blood-glucose, blood lipid and lifestyle habits between MS patients and non-MS population was compared, latent variables were extracted by exploratory factor analysis to determine the structure model, and then a partial least squares path model was constructed between lifestyle habits and the components of MS. Participants'age was (46.62 ± 12.16) years old. The overall prevalence of the MS was 22.43% (2967/13 225), 26.49% (2535/9570) in males and 11.82% (432/3655) in females. The prevalence of the MS was statistically different between males and females (χ(2) = 327.08, P < 0.01). Between MS patients and non-MS population, the difference of dietary habits was statistically significant (χ(2) = 166.31, P < 0.01) in MS patients, the rate of vegetarian, mixed and animal food was 23.39% (694/2967), 42.50% (1261/2967) and 34.11% (1012/2967) respectively, while in non-MS population was 30.80% (3159/10 258), 46.37% (4757/10 258), 22.83% (2342/10 258) respectively. Their alcohol consumption has statistical difference (χ(2) = 374.22, P < 0.01) in MS patients, the rate of never or past, occasional and regular drinking was 27.37% (812/2967), 24.71% (733/2967), 47.93% (1422/2967) respectively, and in non-MS population was 39.60% (4062/10 258), 31.36% (3217/10 258), 29.04% (2979/10 258) respectively. The difference of their smoking status was statistically significant (χ(2) = 115.86, P < 0.01) in MS patients, the rate of never or past, occasional and regular smoking was 59.72% (1772/2967), 6.24% (185/2967), 34.04% (1010/2967) respectively, while in non-MS population was 70.03% (7184/10 258), 5.35% (549/10 258), 24.61% (2525/10 258) respectively. Both lifestyle habits and the components of MS were attributable to only one latent variable. After adjustment for age and gender, the path coefficient between the latent component of lifestyle habits and the latent component of MS was 0.22 with statistical significance (t = 6.46, P < 0.01) through bootstrap test. Reliability and validity of the model:the lifestyle latent variable: average variance extracted was 0.53, composite reliability was 0.77 and Cronbach's a was 0.57. The MS latent variable: average variance extracted was 0.45, composite reliability was 0.76 and Cronbach's a was 0.59. Unhealthy lifestyle habits are closely related to MS. Meat diet, excessive drinking and smoking are risk factors for MS.

Reliability of third molar development for age estimation in Gujarati population: A comparative study

PubMed Central

Gandhi, Neha; Jain, Sandeep; Kumar, Manish; Rupakar, Pratik; Choyal, Kanaram; Prajapati, Seema

2015-01-01

Background: Age assessment may be a crucial step in postmortem profiling leading to confirmative identification. In children, Demirjian's method based on eight developmental stages was developed to determine maturity scores as a function of age and polynomial functions to determine age as a function of score. Aim: Of this study was to evaluate the reliability of age estimation using Demirjian's eight teeth method following the French maturity scores and Indian-specific formula from developmental stages of third molar with the help of orthopantomograms using the Demirjian method. Materials and Methods: Dental panoramic tomograms from 30 subjects each of known chronological age and sex were collected and were evaluated according to Demirjian's criteria. Age calculations were performed using Demirjian's formula and Indian formula. Statistical analysis used was Chi-square test and ANOVA test and the P values obtained were statistically significant. Results: There was an average underestimation of age with both Indian and Demirjian's formulas. The mean absolute error was lower using Indian formula hence it can be applied for age estimation in present Gujarati population. Also, females were ahead of achieving dental maturity than males thus completion of dental development is attained earlier in females. Conclusion: Greater accuracy can be obtained if population-specific formulas considering the ethnic and environmental variation are derived performing the regression analysis. PMID:26005298

Oral Health on Wheels: A Service Learning Project for Dental Hygiene Students.

PubMed

Flick, Heather; Barrett, Sheri; Carter-Hanson, Carrie

2016-08-01

To provide dental hygiene students with a service learning opportunity to work with special needs and culturally diverse underserved populations through the Oral Health on Wheels (OHOW) community based mobile dental hygiene clinic. A student feedback survey was administered between the years of 2009 and 2013 to 90 students in order to gather and identify significant satisfaction, skills acquisition and personal growth information after the student's clinical experience on the OHOW. ANOVA and Pearson correlation coefficient statistical analysis were utilized to investigate relationships between student responses to key questions in the survey. An analysis of 85 student responses (94.44%) demonstrated statistically significant correlations between student learning and their understanding of underserved populations, building confidence in skills, participation as a dental team member and understanding their role in total patient care. The strong correlations between these key questions related to the clinical experience and students confidence, skills integration into the dental team, and understanding of both total patient care, and the increased understanding of the oral health care needs of special populations. All questions directly link to the core mission of the OHOW program. The OHOW clinical experience allows dental hygiene students a unique opportunity to engage in their community while acquiring necessary clinical competencies required by national accreditation and providing access to oral health care services to underserved patients who would otherwise go without treatment. Copyright © 2016 The American Dental Hygienists’ Association.

GIS-based spatial statistical analysis of risk areas for liver flukes in Surin Province of Thailand.

PubMed

Rujirakul, Ratana; Ueng-arporn, Naporn; Kaewpitoon, Soraya; Loyd, Ryan J; Kaewthani, Sarochinee; Kaewpitoon, Natthawut

2015-01-01

It is urgently necessary to be aware of the distribution and risk areas of liver fluke, Opisthorchis viverrini, for proper allocation of prevention and control measures. This study aimed to investigate the human behavior, and environmental factors influencing the distribution in Surin Province of Thailand, and to build a model using stepwise multiple regression analysis with a geographic information system (GIS) on environment and climate data. The relationship between the human behavior, attitudes (<50%; X111), environmental factors like population density (148-169 pop/km2; X73), and land use as wetland (X64), were correlated with the liver fluke disease distribution at 0.000, 0.034, and 0.006 levels, respectively. Multiple regression analysis, by equations OV=-0.599+0.005(population density (148-169 pop/km2); X73)+0.040 (human attitude (<50%); X111)+0.022 (land used (wetland; X64), was used to predict the distribution of liver fluke. OV is the patients of liver fluke infection, R Square=0.878, and, Adjust R Square=0.849. By GIS analysis, we found Si Narong, Sangkha, Phanom Dong Rak, Mueang Surin, Non Narai, Samrong Thap, Chumphon Buri, and Rattanaburi to have the highest distributions in Surin province. In conclusion, the combination of GIS and statistical analysis can help simulate the spatial distribution and risk areas of liver fluke, and thus may be an important tool for future planning of prevention and control measures.

Stroke prevalence among the Spanish elderly: an analysis based on screening surveys

PubMed Central

Boix, Raquel; del Barrio, José Luis; Saz, Pedro; Reñé, Ramón; Manubens, José María; Lobo, Antonio; Gascón, Jordi; de Arce, Ana; Díaz-Guzmán, Jaime; Bergareche, Alberto; Bermejo-Pareja, Félix; de Pedro-Cuesta, Jesús

2006-01-01

Background This study sought to describe stroke prevalence in Spanish elderly populations and compare it against that of other European countries. Methods We identified screening surveys -both published and unpublished- in Spanish populations, which fulfilled specific quality requirements and targeted prevalence of stroke in populations aged 70 years and over. Surveys covering seven geographically different populations with prevalence years in the period 1991–2002 were selected, and the respective authors were then asked to provide descriptions of the methodology and raw age-specific data by completing a questionnaire. In addition, five reported screening surveys in European populations furnished useful data for comparison purposes. Prevalence data were combined, using direct adjustment and logistic regression. Results The overall study population, resident in central and north-eastern Spain, totalled 10,647 persons and yielded 715 cases. Age-adjusted prevalences, using the European standard population, were 7.3% for men, 5.6% for women, and 6.4% for both sexes. Prevalence was significantly lower in women, OR 0.79 95% CI 0.68–0.93, increased with age, particularly among women, and displayed a threefold spatial variation with statistically significant differences. Prevalences were highest, 8.7%, in suburban, and lowest, 3.8%, in rural populations. Compared to pooled Spanish populations, statistically significant differences were seen in eight Italian populations, OR 1.39 95%CI (1.18–1.64), and in Kungsholmen, Sweden, OR 0.40 95%CI (0.27–0.58). Conclusion Prevalence in central and north-eastern Spain is higher in males and in suburban areas, and displays a threefold geographic variation, with women constituting the majority of elderly stroke sufferers. Compared to reported European data, stroke prevalence in Spain can be said to be medium and presents similar age- and sex-specific traits. PMID:17042941

Statistical Analysis of a Large Sample Size Pyroshock Test Data Set Including Post Flight Data Assessment. Revision 1

NASA Technical Reports Server (NTRS)

Hughes, William O.; McNelis, Anne M.

2010-01-01

The Earth Observing System (EOS) Terra spacecraft was launched on an Atlas IIAS launch vehicle on its mission to observe planet Earth in late 1999. Prior to launch, the new design of the spacecraft's pyroshock separation system was characterized by a series of 13 separation ground tests. The analysis methods used to evaluate this unusually large amount of shock data will be discussed in this paper, with particular emphasis on population distributions and finding statistically significant families of data, leading to an overall shock separation interface level. The wealth of ground test data also allowed a derivation of a Mission Assurance level for the flight. All of the flight shock measurements were below the EOS Terra Mission Assurance level thus contributing to the overall success of the EOS Terra mission. The effectiveness of the statistical methodology for characterizing the shock interface level and for developing a flight Mission Assurance level from a large sample size of shock data is demonstrated in this paper.

Model Fit and Item Factor Analysis: Overfactoring, Underfactoring, and a Program to Guide Interpretation.

PubMed

Clark, D Angus; Bowles, Ryan P

2018-04-23

In exploratory item factor analysis (IFA), researchers may use model fit statistics and commonly invoked fit thresholds to help determine the dimensionality of an assessment. However, these indices and thresholds may mislead as they were developed in a confirmatory framework for models with continuous, not categorical, indicators. The present study used Monte Carlo simulation methods to investigate the ability of popular model fit statistics (chi-square, root mean square error of approximation, the comparative fit index, and the Tucker-Lewis index) and their standard cutoff values to detect the optimal number of latent dimensions underlying sets of dichotomous items. Models were fit to data generated from three-factor population structures that varied in factor loading magnitude, factor intercorrelation magnitude, number of indicators, and whether cross loadings or minor factors were included. The effectiveness of the thresholds varied across fit statistics, and was conditional on many features of the underlying model. Together, results suggest that conventional fit thresholds offer questionable utility in the context of IFA.

Extending Working Life: Which Competencies are Crucial in Near-Retirement Age?

PubMed

Wiktorowicz, Justyna

2018-01-01

Nowadays, one of the most important economic and social phenomena is population ageing. Due to the low activity rate of older people, one of the most important challenges is to take various actions involving active ageing, which is supposed to extending working life, and along with it-improve the competencies of older people. The aim of this paper is to evaluate the relevance of different competencies for extending working life, with limiting the analysis for Poland. The paper also assesses the competencies of mature Polish people (aged 50+, but still in working age). In the statistical analysis, I used logistic regression, as well as descriptive statistics and appropriate statistical tests. The results show that among the actions aimed at extending working life, the most important are those related to lifelong learning, targeted at improving the competencies of the older generation. The competencies (both soft and hard) of people aged 50+ are more important than their formal education.

[Landscape and ecological genomics].

PubMed

Tetushkin, E Ia

2013-10-01

Landscape genomics is the modern version of landscape genetics, a discipline that arose approximately 10 years ago as a combination of population genetics, landscape ecology, and spatial statistics. It studies the effects of environmental variables on gene flow and other microevolutionary processes that determine genetic connectivity and variations in populations. In contrast to population genetics, it operates at the level of individual specimens rather than at the level of population samples. Another important difference between landscape genetics and genomics and population genetics is that, in the former, the analysis of gene flow and local adaptations takes quantitative account of landforms and features of the matrix, i.e., hostile spaces that separate species habitats. Landscape genomics is a part of population ecogenomics, which, along with community genomics, is a major part of ecological genomics. One of the principal purposes of landscape genomics is the identification and differentiation of various genome-wide and locus-specific effects. The approaches and computation tools developed for combined analysis of genomic and landscape variables make it possible to detect adaptation-related genome fragments, which facilitates the planning of conservation efforts and the prediction of species' fate in response to expected changes in the environment.

[The general methodological approaches identifying strategic positions in developing healthy lifestyle of population].

PubMed

Dorofeev, S B; Babenko, A I

2017-01-01

The article deals with analysis of national and international publications concerning methodological aspects of elaborating systematic approach to healthy life-style of population. This scope of inquiry plays a key role in development of human capital. The costs related to healthy life-style are to be considered as personal investment into future income due to physical incrementation of human capital. The definitions of healthy life-style, its categories and supportive factors are to be considered in the process of development of strategies and programs of healthy lifestyle. The implementation of particular strategies entails application of comprehensive information and educational programs meant for various categories of population. Therefore, different motivation techniques are to be considered for children, adolescents, able-bodied population, the elderly. This approach is to be resulted in establishing particular responsibility for national government, territorial administrations, health care administrations, employers and population itself. The necessity of complex legislative measures is emphasized. The recent social hygienic studies were focused mostly on particular aspects of development of healthy life-style of population. Hence, the demand for long term exploration of development of organizational and functional models implementing medical preventive measures on the basis of comprehensive information analysis using statistical, sociological and professional expertise.

Clinical, demographic, and laboratory characteristics of children with nephrolithiasis.

PubMed

Sas, David J; Becton, Lauren J; Tutman, Jeffrey; Lindsay, Laura A; Wahlquist, Amy H

2016-06-01

While the incidence of pediatric kidney stones appears to be increasing, little is known about the demographic, clinical, laboratory, imaging, and management variables in this patient population. We sought to describe various characteristics of our stone-forming pediatric population. To that end, we retrospectively reviewed the charts of pediatric patients with nephrolithiasis confirmed by imaging. Data were collected on multiple variables from each patient and analyzed for trends. For body mass index (BMI) controls, data from the general pediatrics population similar to our nephrolithiasis population were used. Data on 155 pediatric nephrolithiasis patients were analyzed. Of the 54 calculi available for analysis, 98 % were calcium based. Low urine volume, elevated supersaturation of calcium phosphate, elevated supersaturation of calcium oxalate, and hypercalciuria were the most commonly identified abnormalities on analysis of 24-h urine collections. Our stone-forming population did not have a higher BMI than our general pediatrics population, making it unlikely that obesity is a risk factor for nephrolithiasis in children. More girls presented with their first stone during adolescence, suggesting a role for reproductive hormones contributing to stone risk, while boys tended to present more commonly at a younger age, though this did not reach statistical significance. These intriguing findings warrant further investigation.

Apolipoprotein C3 Gene Polymorphisms Are Not a Risk Factor for Developing Non-Alcoholic Fatty Liver Disease: A Meta-Analysis

PubMed Central

Zhang, Haiying; Chen, Lizhen; Xin, Yongning; Lou, Yuangui; Liu, Yang; Xuan, Shiying

2014-01-01

Context: Our objective was to evaluate the effect of gene polymorphisms of apolipoprotein C3 (APOC3) on the development of non-alcoholic fatty liver disease (NAFLD) in different populations. Evidence Acquisition: We performed a meta-analysis of all relevant studies published in the literature. A total of 115 clinical trials or reports were identified, but only seven trials met our inclusion criteria. A meta-analysis was performed according to the Cochrane Reviewers’ Handbook recommendations. Results: Five hospital-based and two population-based case-control studies were included in the final analysis. The overall frequency of APOC3 gene polymorphisms was 67.5% (1177/1745) in NAFLD and 68.8% (988/1437) in controls. The summary odds ratio for the association of gene polymorphisms of APOC3 and the risk of NAFLD was 1.03 (95% CI: 0.89-1.22),which was not statistically significant (P > 0.05). Conclusions: Our meta-analysis, while not ruling out possible publication bias, showed no association between gene polymorphisms of APOC3 and the risk of NAFLD development in different populations in the world. PMID:25477977

LOD significance thresholds for QTL analysis in experimental populations of diploid species

PubMed

Van Ooijen JW

1999-11-01

Linkage analysis with molecular genetic markers is a very powerful tool in the biological research of quantitative traits. The lack of an easy way to know what areas of the genome can be designated as statistically significant for containing a gene affecting the quantitative trait of interest hampers the important prediction of the rate of false positives. In this paper four tables, obtained by large-scale simulations, are presented that can be used with a simple formula to get the false-positives rate for analyses of the standard types of experimental populations with diploid species with any size of genome. A new definition of the term 'suggestive linkage' is proposed that allows a more objective comparison of results across species.

A review of small canned computer programs for survey research and demographic analysis.

PubMed

Sinquefield, J C

1976-12-01

A variety of small canned computer programs for survey research and demographic analysis appropriate for use in developing countries are reviewed in this article. The programs discussed are SPSS (Statistical Package for the Social Sciences); CENTS, CO-CENTS, CENTS-AID, CENTS-AIE II; MINI-TAB EDIT, FREQUENCIES, TABLES, REGRESSION, CLIENT RECORD, DATES, MULT, LIFE, and PREGNANCY HISTORY; FIVFIV and SINSIN; DCL (Demographic Computer Library); MINI-TAB Population Projection, Functional Population Projection, and Family Planning Target Projection. A description and evaluation for each program of uses, instruction manuals, computer requirements, and procedures for obtaining manuals and programs are provided. Such information is intended to facilitate and encourage the use of the computer by data processors in developing countries.

Genetic variation and structure in remnant population of critically endangered Melicope zahlbruckneri

USGS Publications Warehouse

Raji, J. A.; Atkinson, Carter T.

2016-01-01

The distribution and amount of genetic variation within and between populations of plant species are important for their adaptability to future habitat changes and also critical for their restoration and overall management. This study was initiated to assess the genetic status of the remnant population of Melicope zahlbruckneri–a critically endangered species in Hawaii, and determine the extent of genetic variation and diversity in order to propose valuable conservation approaches. Estimated genetic structure of individuals based on molecular marker allele frequencies identified genetic groups with low overall differentiation but identified the most genetically diverse individuals within the population. Analysis of Amplified Fragment Length Polymorphic (AFLP) marker loci in the population based on Bayesian model and multivariate statistics classified the population into four subgroups. We inferred a mixed species population structure based on Bayesian clustering and frequency of unique alleles. The percentage of Polymorphic Fragment (PPF) ranged from 18.8 to 64.6% for all marker loci with an average of 54.9% within the population. Inclusion of all surviving M. zahlbruckneri trees in future restorative planting at new sites are suggested, and approaches for longer term maintenance of genetic variability are discussed. To our knowledge, this study represents the first report of molecular genetic analysis of the remaining population of M. zahlbruckneri and also illustrates the importance of genetic variability for conservation of a small endangered population.

Detection and evolution of resistance to the pyrethroid cypermethrin in Helicoverpa zea (Lepidoptera: Noctuidae) populations in Texas.

PubMed

Pietrantonio, P V; Junek, T A; Parker, R; Mott, D; Siders, K; Troxclair, N; Vargas-Camplis, J; Westbrook, J K; Vassiliou, V A

2007-10-01

The bollworm, Helicoverpa zea (Boddie), is a key pest of cotton in Texas. Bollworm populations are widely controlled with pyrethroid insecticides in cotton and exposed to pyrethroids in other major crops such as grain sorghum, corn, and soybeans. A statewide program that evaluated cypermethrin resistance in male bollworm populations using an adult vial test was conducted from 2003 to 2006 in the major cotton production regions of Texas. Estimated parameters from the most susceptible field population currently available (Burleson County, September 2005) were used to calculate resistance ratios and their statistical significance. Populations from several counties had statistically significant (P < or = 0.05) resistance ratios for the LC(50), indicating that bollworm-resistant populations are widespread in Texas. The highest resistance ratios for the LC(50) were observed for populations in Burleson County in 2000 and 2003, Nueces County in 2004, and Williamson and Uvalde Counties in 2005. These findings explain the observed pyrethroid control failures in various counties in Texas. Based on the assumption that resistance is caused by a single gene, the Hardy-Weinberg equilibrium formula was used for estimation of frequencies for the putative resistant allele (q) using 3 and 10 microg/vial as discriminatory dosages for susceptible and heterozygote resistant insects, respectively. The influence of migration on local levels of resistance was estimated by analysis of wind trajectories, which partially clarifies the rapid evolution of resistance to cypermethrin in bollworm populations. This approach could be used in evaluating resistance evolution in other migratory pests.

Parental timing of allergenic food introduction in urban and suburban populations.

PubMed

Hartman, Heather; Dodd, Caitlin; Rao, Marepalli; DeBlasio, Dominick; Labowsky, Christine; D'Souza, Sharon; Lenkauskas, Siga; Roeser, Eve; Heffernan, Alison; Assa'ad, Amal

2016-07-01

Recommendations on timing for introduction of allergenic foods in an infant diet have changed twice during the past decade. How families with different demographic characteristics implement the change has not been studied in the United States. To compare the age of introduction of allergenic foods between an urban Medicaid-based population and a suburban private insurance-based population in Cincinnati, Ohio. Two hundred parent surveys were distributed at well-child checkups between 4 and 36 months of age. Data were analyzed using distribution mapping to determine the difference in the age of introduction of infant formula, infant solids, whole cow's milk, eggs, peanut, and fish. Random forest analysis was used to determine the most important factors affecting the age of introduction for both populations. There was no statistically significant difference in the age of infant solid introduction, but urban populations introduced allergenic foods earlier than suburban populations, with a statistically significant difference in the age of introduction of infant formula, whole cow's milk, eggs, peanut, and fish. The most important factor for the timing of all food introductions was the recommended age of introduction from health care professionals. There is a difference between urban and suburban populations in the timing of introduction of allergenic foods but not in other infant solid foods. The reliance on physician recommendation for both populations supports the need for education and guidance to health care professionals on up-to-date guidance and recommendations. Copyright © 2016 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Mapping genes underlying ethnic differences in disease risk by linkage disequilibrium in recently admixed populations.

PubMed Central

McKeigue, P M

1997-01-01

Where recent admixture has occurred between two populations that have different disease rates for genetic reasons, family-based association studies can be used to map the genes underlying these differences, if the ancestry of the alleles at each locus examined can be assigned to one of the two founding populations. This article explores the statistical power and design requirements of this approach. Markers suitable for assigning the ancestry of genomic regions could be defined by grouping alleles at closely spaced microsatellite loci into haplotypes, or generated by representational difference analysis. For a given relative risk between populations, the sample size required to detect a disease locus that accounts for this relative risk by linkage-disequilibrium mapping in an admixed population is not critically dependent on assumptions about genotype penetrances or allele frequencies. Using the transmission-disequilibrium test to search the genome for a locus that accounts for a relative risk of between 2 and 3 in a high-risk population, compared with a low-risk population, generally requires between 150 and 800 case-parent pairs of mixed descent. The optimal strategy is to conduct an initial study using markers spaced at < or = 10 cM with cases from the second and third generations of mixed descent, and then to map the disease loci more accurately in a subsequent study of a population with a longer history of admixture. This approach has greater statistical power than allele-sharing designs and has obvious applications to the genetics of hypertension, non-insulin-dependent diabetes, and obesity. PMID:8981962

Population genetic inference from personal genome data: impact of ancestry and admixture on human genomic variation.

PubMed

Kidd, Jeffrey M; Gravel, Simon; Byrnes, Jake; Moreno-Estrada, Andres; Musharoff, Shaila; Bryc, Katarzyna; Degenhardt, Jeremiah D; Brisbin, Abra; Sheth, Vrunda; Chen, Rong; McLaughlin, Stephen F; Peckham, Heather E; Omberg, Larsson; Bormann Chung, Christina A; Stanley, Sarah; Pearlstein, Kevin; Levandowsky, Elizabeth; Acevedo-Acevedo, Suehelay; Auton, Adam; Keinan, Alon; Acuña-Alonzo, Victor; Barquera-Lozano, Rodrigo; Canizales-Quinteros, Samuel; Eng, Celeste; Burchard, Esteban G; Russell, Archie; Reynolds, Andy; Clark, Andrew G; Reese, Martin G; Lincoln, Stephen E; Butte, Atul J; De La Vega, Francisco M; Bustamante, Carlos D

2012-10-05

Full sequencing of individual human genomes has greatly expanded our understanding of human genetic variation and population history. Here, we present a systematic analysis of 50 human genomes from 11 diverse global populations sequenced at high coverage. Our sample includes 12 individuals who have admixed ancestry and who have varying degrees of recent (within the last 500 years) African, Native American, and European ancestry. We found over 21 million single-nucleotide variants that contribute to a 1.75-fold range in nucleotide heterozygosity across diverse human genomes. This heterozygosity ranged from a high of one heterozygous site per kilobase in west African genomes to a low of 0.57 heterozygous sites per kilobase in segments inferred to have diploid Native American ancestry from the genomes of Mexican and Puerto Rican individuals. We show evidence of all three continental ancestries in the genomes of Mexican, Puerto Rican, and African American populations, and the genome-wide statistics are highly consistent across individuals from a population once ancestry proportions have been accounted for. Using a generalized linear model, we identified subtle variations across populations in the proportion of neutral versus deleterious variation and found that genome-wide statistics vary in admixed populations even once ancestry proportions have been factored in. We further infer that multiple periods of gene flow shaped the diversity of admixed populations in the Americas-70% of the European ancestry in today's African Americans dates back to European gene flow happening only 7-8 generations ago. Copyright © 2012 The American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.

Population Genetic Inference from Personal Genome Data: Impact of Ancestry and Admixture on Human Genomic Variation

PubMed Central

Kidd, Jeffrey M.; Gravel, Simon; Byrnes, Jake; Moreno-Estrada, Andres; Musharoff, Shaila; Bryc, Katarzyna; Degenhardt, Jeremiah D.; Brisbin, Abra; Sheth, Vrunda; Chen, Rong; McLaughlin, Stephen F.; Peckham, Heather E.; Omberg, Larsson; Bormann Chung, Christina A.; Stanley, Sarah; Pearlstein, Kevin; Levandowsky, Elizabeth; Acevedo-Acevedo, Suehelay; Auton, Adam; Keinan, Alon; Acuña-Alonzo, Victor; Barquera-Lozano, Rodrigo; Canizales-Quinteros, Samuel; Eng, Celeste; Burchard, Esteban G.; Russell, Archie; Reynolds, Andy; Clark, Andrew G.; Reese, Martin G.; Lincoln, Stephen E.; Butte, Atul J.; De La Vega, Francisco M.; Bustamante, Carlos D.

2012-01-01

Full sequencing of individual human genomes has greatly expanded our understanding of human genetic variation and population history. Here, we present a systematic analysis of 50 human genomes from 11 diverse global populations sequenced at high coverage. Our sample includes 12 individuals who have admixed ancestry and who have varying degrees of recent (within the last 500 years) African, Native American, and European ancestry. We found over 21 million single-nucleotide variants that contribute to a 1.75-fold range in nucleotide heterozygosity across diverse human genomes. This heterozygosity ranged from a high of one heterozygous site per kilobase in west African genomes to a low of 0.57 heterozygous sites per kilobase in segments inferred to have diploid Native American ancestry from the genomes of Mexican and Puerto Rican individuals. We show evidence of all three continental ancestries in the genomes of Mexican, Puerto Rican, and African American populations, and the genome-wide statistics are highly consistent across individuals from a population once ancestry proportions have been accounted for. Using a generalized linear model, we identified subtle variations across populations in the proportion of neutral versus deleterious variation and found that genome-wide statistics vary in admixed populations even once ancestry proportions have been factored in. We further infer that multiple periods of gene flow shaped the diversity of admixed populations in the Americas—70% of the European ancestry in today’s African Americans dates back to European gene flow happening only 7–8 generations ago. PMID:23040495

Comparative morphological studies on four populations of the shrimp Rimicaris exoculata from the Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Vereshchaka, A. L.

1997-11-01

Four populations (a total of 677 specimens) of the hydrothermal shrimp species Rimicaris exoculata from three Mid-Atlantic Ridge vent fields were studied: Broken Spur (29°N), TAG (26°N), and "14-45" (14°N). Five morphological characters were analysed: number of dorsolateral spines on telson, telative carapace width, relative abdominal length, presence of "abnormal telson", and fat content. Dependences of each character upon shrimp size were analysed. Division of the shrimp ontogenesis on the basis of general morphology is proposed. Phenotypic analysis based upon five selected characters revealed statistically significant divergence between two populations within the same vent field TAG. Probable causes of observed divergence are discussed.

Navigating complex sample analysis using national survey data.

PubMed

Saylor, Jennifer; Friedmann, Erika; Lee, Hyeon Joo

2012-01-01

The National Center for Health Statistics conducts the National Health and Nutrition Examination Survey and other national surveys with probability-based complex sample designs. Goals of national surveys are to provide valid data for the population of the United States. Analyses of data from population surveys present unique challenges in the research process but are valuable avenues to study the health of the United States population. The aim of this study was to demonstrate the importance of using complex data analysis techniques for data obtained with complex multistage sampling design and provide an example of analysis using the SPSS Complex Samples procedure. Illustration of challenges and solutions specific to secondary data analysis of national databases are described using the National Health and Nutrition Examination Survey as the exemplar. Oversampling of small or sensitive groups provides necessary estimates of variability within small groups. Use of weights without complex samples accurately estimates population means and frequency from the sample after accounting for over- or undersampling of specific groups. Weighting alone leads to inappropriate population estimates of variability, because they are computed as if the measures were from the entire population rather than a sample in the data set. The SPSS Complex Samples procedure allows inclusion of all sampling design elements, stratification, clusters, and weights. Use of national data sets allows use of extensive, expensive, and well-documented survey data for exploratory questions but limits analysis to those variables included in the data set. The large sample permits examination of multiple predictors and interactive relationships. Merging data files, availability of data in several waves of surveys, and complex sampling are techniques used to provide a representative sample but present unique challenges. In sophisticated data analysis techniques, use of these data is optimized.

A radiographic survey of agenesis of the third molar: A panoramic study

PubMed Central

Singh, Nisha; Chaudhari, Shrinivas; Chaudhari, Rohan; Nagare, Sagar; Kulkarni, Abhay; Parkarwar, Pratik

2017-01-01

Purpose: It is a well-known fact that nature tries to eliminate what is not in use. Because of this, the number of certain teeth which are no longer necessary for function are either getting increasingly impacted or are not developing at all. This is especially the case where third molars are concerned. Furthermore, the presence or absence of the third molar is significant to all branches of dentistry and in particular, forensic dentistry. Objectives: The objectives of this study is to assess (1) The prevalence of third molar agenesis in population of age group 18–25 years. (2) The genderwise difference of third molar agenesis. (3) The difference between maxilla and mandible. Materials and Methods: Dental patients, who are advised or referred for orthopantomograph, visited to the Department of Oral Medicine and Radiology were included in the study. The study population comprised 300 patients. Statistical Analysis: The data obtained was tabulated and subjected to statistical analysis. SPSS version 17 software was used for the analysis of the data. The Chi-square test was used for the same. Results: The incidence of agenesis of the third molar is significantly higher for tooth number 18 (P < 0.001). Overall, it is significantly higher among females compared to the males (P < 0.001) in our study population. Conclusion: (1) The present study reports 46.7% agenesis of the third molar. (2) The frequency of third molar agenesis was found significantly greater in the females. (3) Third molar agenesis showed a greater predilection in maxilla compared to mandible. PMID:29657489

Plasminogen activator inhibitor-1 4G/5G polymorphism and ischemic stroke risk: a meta-analysis in Chinese population.

PubMed

Cao, Yuezhou; Chen, Weixian; Qian, Yun; Zeng, Yanying; Liu, Wenhua

2014-12-01

The guanosine insertion/deletion polymorphism (4G/5G) of plasminogen activator inhibitor-1 (PAI-1) gene has been suggested as a risk factor for ischemic stroke (IS), but direct evidence from genetic association studies remains inconclusive even in Chinese population. Therefore, we performed a meta-analysis to evaluate this association. All of the relevant studies were identified from PubMed, Embase, Chinese National Knowledge Infrastructure database and Chinese Wanfang database up to September 2013. Statistical analyses were conducted with Revman 5.2 and STATA 12.0 software. Odds ratio (OR) with 95% confidence interval (CI) values were applied to evaluate the strength of the association. Heterogeneity was evaluated by Q-test and the I² statistic. The Begg's test and Egger's test were used to assess the publication bias. A significant association and a borderline association between the PAI-1 4G/5G polymorphism and IS were found under the recessive model (OR = 1.639, 95% CI = 1.136-2.364) and allelic model (OR = 1.256, 95% CI = 1.000-1.578), respectively. However, no significant association was observed under homogeneous comparison model (OR = 1.428, 95% CI = 0.914-2.233), heterogeneous comparison model (OR = 0.856, 95% CI = 0.689-1.063) and dominant model (OR = 1.036, 95% CI = 0.846-1.270). This meta-analysis suggested that 4G4G genotype of PAI-1 4G/5G polymorphism might be a risk factor for IS in the Chinese population.

Inside Rural Pennsylvania: A Statistical Profile.

ERIC Educational Resources Information Center

Center for Rural Pennsylvania, Harrisburg.

Graphs, data tables, maps, and written descriptions give a statistical overview of rural Pennsylvania. A section on rural demographics covers population changes, racial and ethnic makeup, age cohorts, and families and income. Pennsylvania's rural population, the nation's largest, has increased more than its urban population since 1950, with the…

Repeatability of Cryogenic Multilayer Insulation

NASA Technical Reports Server (NTRS)

Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

2017-01-01

Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between multiple identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five GRC provided coupons with 25 layers was shown to be +/- 8.4 whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0. A second group of 10 coupons have been fabricated by Yetispace and tested by Florida State University, through the first 4 tests, the repeatability has been shown to be +/- 16. Based on detailed statistical analysis, the data has been shown to be statistically significant.

Repeatability of Cryogenic Multilayer Insulation

NASA Technical Reports Server (NTRS)

Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

2017-01-01

Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between multiple identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five GRC provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons have been fabricated by Yetispace and tested by Florida State University, through the first 4 tests, the repeatability has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

Repeatability of Cryogenic Multilayer Insulation

NASA Astrophysics Data System (ADS)

Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

2017-12-01

Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation (MLI) has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five Glenn Research Center (GRC) provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons has been fabricated by Yetispace and tested by Florida State University, the repeatability between coupons has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

Bio++: a set of C++ libraries for sequence analysis, phylogenetics, molecular evolution and population genetics.

PubMed

Dutheil, Julien; Gaillard, Sylvain; Bazin, Eric; Glémin, Sylvain; Ranwez, Vincent; Galtier, Nicolas; Belkhir, Khalid

2006-04-04

A large number of bioinformatics applications in the fields of bio-sequence analysis, molecular evolution and population genetics typically share input/output methods, data storage requirements and data analysis algorithms. Such common features may be conveniently bundled into re-usable libraries, which enable the rapid development of new methods and robust applications. We present Bio++, a set of Object Oriented libraries written in C++. Available components include classes for data storage and handling (nucleotide/amino-acid/codon sequences, trees, distance matrices, population genetics datasets), various input/output formats, basic sequence manipulation (concatenation, transcription, translation, etc.), phylogenetic analysis (maximum parsimony, markov models, distance methods, likelihood computation and maximization), population genetics/genomics (diversity statistics, neutrality tests, various multi-locus analyses) and various algorithms for numerical calculus. Implementation of methods aims at being both efficient and user-friendly. A special concern was given to the library design to enable easy extension and new methods development. We defined a general hierarchy of classes that allow the developer to implement its own algorithms while remaining compatible with the rest of the libraries. Bio++ source code is distributed free of charge under the CeCILL general public licence from its website http://kimura.univ-montp2.fr/BioPP.

The prevalence of insomnia in the general population in China: A meta-analysis

PubMed Central

Zhong, Bao-Liang; Zhang, Ling; Ungvari, Gabor S.; Ng, Chee H.; Li, Lu; Chiu, Helen F. K.; Lok, Grace K. I.; Lu, Jian-Ping; Jia, Fu-Jun; Xiang, Yu-Tao

2017-01-01

This is the first meta-analysis of the pooled prevalence of insomnia in the general population of China. A systematic literature search was conducted via the following databases: PubMed, PsycINFO, EMBASE and Chinese databases (China National Knowledge Interne (CNKI), WanFang Data and SinoMed). Statistical analyses were performed using the Comprehensive Meta-Analysis program. A total of 17 studies with 115,988 participants met the inclusion criteria for the analysis. The pooled prevalence of insomnia in China was 15.0% (95% Confidence interval [CI]: 12.1%-18.5%). No significant difference was found in the prevalence between genders or across time period. The pooled prevalence of insomnia in population with a mean age of 43.7 years and older (11.6%; 95% CI: 7.5%-17.6%) was significantly lower than in those with a mean age younger than 43.7 years (20.4%; 95% CI: 14.2%-28.2%). The prevalence of insomnia was significantly affected by the type of assessment tools (Q = 14.1, P = 0.001). The general population prevalence of insomnia in China is lower than those reported in Western countries but similar to those in Asian countries. Younger Chinese adults appear to suffer from more insomnia than older adults. Trial Registration: CRD 42016043620 PMID:28234940

15 CFR 50.40 - Fee structure for statistics for city blocks in the 1980 Census of Population and Housing.

Code of Federal Regulations, 2012 CFR

2012-01-01

... blocks in the 1980 Census of Population and Housing. 50.40 Section 50.40 Commerce and Foreign Trade... the 1980 Census of Population and Housing. (a) As part of the regular program of the 1980 census, the Census Bureau will publish printed reports containing certain summary population and housing statistics...

15 CFR 50.40 - Fee structure for statistics for city blocks in the 1980 Census of Population and Housing.

Code of Federal Regulations, 2013 CFR

2013-01-01

... blocks in the 1980 Census of Population and Housing. 50.40 Section 50.40 Commerce and Foreign Trade... the 1980 Census of Population and Housing. (a) As part of the regular program of the 1980 census, the Census Bureau will publish printed reports containing certain summary population and housing statistics...

15 CFR 50.40 - Fee structure for statistics for city blocks in the 1980 Census of Population and Housing.

Code of Federal Regulations, 2014 CFR

2014-01-01

... blocks in the 1980 Census of Population and Housing. 50.40 Section 50.40 Commerce and Foreign Trade... the 1980 Census of Population and Housing. (a) As part of the regular program of the 1980 census, the Census Bureau will publish printed reports containing certain summary population and housing statistics...

A bottom up approach to on-road CO2 emissions estimates: improved spatial accuracy and applications for regional planning.

PubMed

Gately, Conor K; Hutyra, Lucy R; Wing, Ian Sue; Brondfield, Max N

2013-03-05

On-road transportation is responsible for 28% of all U.S. fossil-fuel CO2 emissions. Mapping vehicle emissions at regional scales is challenging due to data limitations. Existing emission inventories use spatial proxies such as population and road density to downscale national or state-level data. Such procedures introduce errors where the proxy variables and actual emissions are weakly correlated, and limit analysis of the relationship between emissions and demographic trends at local scales. We develop an on-road emission inventory product for Massachusetts-based on roadway-level traffic data obtained from the Highway Performance Monitoring System (HPMS). We provide annual estimates of on-road CO2 emissions at a 1 × 1 km grid scale for the years 1980 through 2008. We compared our results with on-road emissions estimates from the Emissions Database for Global Atmospheric Research (EDGAR), with the Vulcan Product, and with estimates derived from state fuel consumption statistics reported by the Federal Highway Administration (FHWA). Our model differs from FHWA estimates by less than 8.5% on average, and is within 5% of Vulcan estimates. We found that EDGAR estimates systematically exceed FHWA by an average of 22.8%. Panel regression analysis of per-mile CO2 emissions on population density at the town scale shows a statistically significant correlation that varies systematically in sign and magnitude as population density increases. Population density has a positive correlation with per-mile CO2 emissions for densities below 2000 persons km(-2), above which increasing density correlates negatively with per-mile emissions.

Genetic analysis of Aedes albopictus (Diptera, Culicidae) reveals a deep divergence in the original regions.

PubMed

Ruiling, Zhang; Tongkai, Liu; Zhendong, Huang; Guifen, Zhuang; Dezhen, Ma; Zhong, Zhang

2018-05-02

Aedes albopictus has been described as one of the 100 worst invasive species in the world. This mosquito originated from southeastern Asia and currently has a widespread presence in every continent except Antarctica. The rapid global expansion of Ae. albopictus has increased public health concerns about arbovirus-related disease threats. Adaptation, adaption to novel areas is a biological challenge for invasive species, and the underlying processes can be studied at the molecular level. In this study, genetic analysis was performed using mitochondrial gene NADH dehydrogenase subunit 5 (ND5), based on both native and invasive populations. Altogether, 38 haplotypes were detected with H1 being the dominant and widely distributed in 21 countries. Both phylogenetic and network analyses supported the existence of five clades, with only clade I being involved in the subsequent global spread of Asian tiger mosquito. The other four clades (II, III, IV and V) were restricted to their original regions, which could be ancestral populations that had diverged from clade I in the early stages of evolution. Neutrality tests suggested that most of the populations had experienced recent expansion. Analysis of molecular variance and the population-pair statistic F ST revealed that most populations lacked genetic structure, while high variability was detected within populations. Multiple and independent human-mediated introductions may explain the present results. Copyright © 2018 Elsevier B.V. All rights reserved.

[Epidemiologic findings on the spontaneous long-term course of psychogenic disease over 10 years].

PubMed

Franz, M; Schepank, H; Reister, G; Schellberg, D

1994-01-01

207 individuals were selected from a random sample of the adult urban population of Mannheim according to the criterion of medium psychogenic impairment (high-risk population) and investigated three times between 1979 and 1991 with regard to prevalence and severity of psychogenic disorders. In contrast to clinical investigations, the present data render statements on the spontaneous course of psychogenic disorders in the general population. The existing psychogenic impairment was determined by means of various operationalizations (symptomatology, ICD-diagnoses, severity of impairment). The available data indicate a high stability of psychogenic impairment in the spontaneous course. Group statistically the severity of impairment even increases in the long term course. However, different subtypes of course in the investigated high-risk population can be identified by a cluster analysis.

Population forecasts for Bangladesh, using a Bayesian methodology.

PubMed

Mahsin, Md; Hossain, Syed Shahadat

2012-12-01

Population projection for many developing countries could be quite a challenging task for the demographers mostly due to lack of availability of enough reliable data. The objective of this paper is to present an overview of the existing methods for population forecasting and to propose an alternative based on the Bayesian statistics, combining the formality of inference. The analysis has been made using Markov Chain Monte Carlo (MCMC) technique for Bayesian methodology available with the software WinBUGS. Convergence diagnostic techniques available with the WinBUGS software have been applied to ensure the convergence of the chains necessary for the implementation of MCMC. The Bayesian approach allows for the use of observed data and expert judgements by means of appropriate priors, and a more realistic population forecasts, along with associated uncertainty, has been possible.

Enteroaggregative Escherichia coli have evolved independently as distinct complexes within the E. coli population with varying ability to cause disease.

PubMed

Chattaway, Marie Anne; Jenkins, Claire; Rajendram, Dunstan; Cravioto, Alejandro; Talukder, Kaisar Ali; Dallman, Tim; Underwood, Anthony; Platt, Steve; Okeke, Iruka N; Wain, John

2014-01-01

Enteroaggregative E. coli (EAEC) is an established diarrhoeagenic pathotype. The association with virulence gene content and ability to cause disease has been studied but little is known about the population structure of EAEC and how this pathotype evolved. Analysis by Multi Locus Sequence Typing of 564 EAEC isolates from cases and controls in Bangladesh, Nigeria and the UK spanning the past 29 years, revealed multiple successful lineages of EAEC. The population structure of EAEC indicates some clusters are statistically associated with disease or carriage, further highlighting the heterogeneous nature of this group of organisms. Different clusters have evolved independently as a result of both mutational and recombination events; the EAEC phenotype is distributed throughout the population of E. coli.

Diabetes mellitus increases the risk of ruptured abdominal aortic aneurysms.

PubMed

Wierzba, Waldemar; Sliwczynski, Andrzej; Pinkas, Jaroslaw; Jawien, Arkadiusz; Karnafel, Waldemar

2017-09-01

The publication is a polemical response to reports that present data that diabetes reduces the risk of rupture of abdominal aortic aneurysm (AAA). The study analyzed all cases of developing AAA in patients with and without diabetes in 2012 in Poland. Data for the analysis were obtained with a unique and complete resources of the National Health Fund (NFZ) and population data from the Central Statistical Office (GUS). In Poland during 2012 2,227,453 patients with diabetes were treated, 975,364 males and 1,252,089 females. The incidence of AAA without rupture in patients without diabetes calculated per 100,000 of the non-diabetes general population was 25.0 +/- 9.0 in males and 5.6 +/- 2.3 in females. The incidence of ruptured AAA in the general population without diabetes was 3.6 +/- 0.9 in males, and 0.6 +/- 0.3 in females calculated per 100,000 of inhabitants without diabetes. The incidence of AAA without rupture in patients with diabetes was 184.897 +/- 70.653 in males and 35.364 +/- 24.925 in females calculated per 100,000 of patients diagnosed with diabetes. The incidence of ruptured AAA in patients with diabetes was 21.090 +/- 6.050 in males and 5.170 +/- 3.053 in females calculated per 100,000 of patients diagnosed with diabetes. The incidence rate for ruptured AAA in 2012 in Poland is statistically higher both in females and males in the population with diabetes. The incidence rate for AAA without rupture in 2012 in Poland is statistically higher in patients diagnosed with diabetes.

Economic effect of an expansion of pharmacy benefits on total health care expenditures by a state Medicaid program.

PubMed

Jenkins, Tara L; Harrison, Donald L; Jacobs, Elgene W; Neas, Barbara R; Hagemann, Tracy M

2009-01-01

To evaluate the economic effect of a pharmacy benefit expansion on a population of Oklahoma Medicaid recipients and to determine whether recipients who routinely maximized their monthly prescription limit (cap) before the benefit expansion benefited more from the expansion than the remainder of the study population. Retrospective study. Oklahoma Medicaid claims data from January 1, 2003, to December 31, 2004. Data from 15,936 Oklahoma Medicaid recipients. Retrospective administrative analysis using the Oklahoma Health Care Authority pharmacy and medical claims databases. Total health care expenditures per recipient per year, total medical expenditures per recipient per year, and total pharmacy expenditures per recipient per year. Total health care expenditures increased 17% after the benefit expansion (P < 0.0001). Of this increase, 65% was attributed to pharmacy expenditures and 35% to medical expenditures. However, a subpopulation of recipients who routinely reached their prescription limit before the expansion had a statistically significant increase in total and pharmacy expenditures; a statistically significant increase in medical expenditures was not observed. Although total health care expenditures increased after a monthly pharmacy benefit in a Medicaid population was expanded, a subpopulation of recipients identified as high pharmacy users before the expansion did not have a statistically significant increase in medical expenditures, whereas those who were non-high users experienced a significant increase. Additionally, this subpopulation experienced a nonsignificant decrease in hospital expenditures. These results could suggest that this subpopulation was affected differently than the overall population by the expansion of the Medicaid pharmacy benefit.

Awareness of osteoporosis in postmenopausal Indian women: An evaluation of Osteoporosis Health Belief Scale.

PubMed

Gopinathan, Nirmal Raj; Sen, Ramesh Kumar; Behera, Prateek; Aggarwal, Sameer; Khandelwal, Niranjan; Sen, Mitali

2016-01-01

The level of awareness about osteoporosis in postmenopausal women who are the common sufferers. This study aims to evaluate the level of awareness in postmenopausal women using the Osteoporosis Health Belief Scale (OHBS). Osteoporosis has emerged as a common health problem in geriatric population. A proactive role needs to be played for preventing its consequences. Before initiating any preventive measures, an evaluation of awareness level of the target population is necessary. The questionnaire-based study design was used for this study. A questionnaire (OHBS)-based study in 100 postmenopausal women in Chandigarh was conducted. The bone mineral density (BMD) was measured in each case by dual energy X-ray absorptiometry. Height, weight, and body mass index (BMI) of the participants were noted. Statistical analysis was conducted to evaluate any correlation between the various components of the OHBS and the BMD. No statistically significant difference was noted in the seven component parameters of OHBS among the normal, osteopenic, and osteoporotic women suggesting that the health belief regarding susceptibility is not much different between the three groups of the study population. A statistically significant difference between the mean BMI of normal and osteoporotic population was noted. The results show that there is a great deficit in the awareness level of postmenopausal Indian women regarding osteoporosis. Most of the women were unaware of the condition and the means to prevent it. The study emphasizes that health care professionals have lot of ground to cover to decrease the incidence of osteoporosis and its associated health problem.

Safety and Efficacy of D-Tagatose in Glycemic Control in Subjects with Type 2 Diabetes.

PubMed

Ensor, Mark; Banfield, Amy B; Smith, Rebecca R; Williams, Jarrod; Lodder, Robert A

The primary objectives of this study were to evaluate the treatment effect of D-tagatose on glycemic control, determined by a statistically significant decrease in hemoglobin A1c (HbA1c), and safety profile of D-tagatose compared to placebo. The secondary objectives were to evaluate the treatment effects on fasting blood glucose, insulin, lipid profiles, changes in BMI, and the proportion of subjects achieving HbA1c targets of <7%. Type 2 diabetic patients not taking any blood glucose lowering medications were administered either 15 g of D-tagatose dissolved in 125-250 ml of water three times a day or placebo with meals. Reduction in HbA1c was statistically significant compared to placebo at all post-baseline time points in the ITT population. Additionally, secondary endpoints were achieved in the ITT population with regard to LDL, total cholesterol, fasting blood glucose, and proportion of subjects achieving HbA1c targets of <7%. D-tagatose was unable to lower triglycerides or raise HDL compared to placebo. A subgroup LOCF analysis on the ITT US population showed a greater and statistically significant LS mean reduction in HbA1c in the D-tagatose group at all post-baseline visits. Based on these results it is concluded that in the ITT population D-tagatose is an effective single agent at treating many of the therapy targets of type 2 diabetes including lowering fasting blood glucose and HbA1c, and lowering of LDL and total cholesterol.

Safety and Efficacy of D-Tagatose in Glycemic Control in Subjects with Type 2 Diabetes

PubMed Central

Ensor, Mark; Banfield, Amy B.; Smith, Rebecca R.; Williams, Jarrod; Lodder, Robert A.

2015-01-01

The primary objectives of this study were to evaluate the treatment effect of D-tagatose on glycemic control, determined by a statistically significant decrease in hemoglobin A1c (HbA1c), and safety profile of D-tagatose compared to placebo. The secondary objectives were to evaluate the treatment effects on fasting blood glucose, insulin, lipid profiles, changes in BMI, and the proportion of subjects achieving HbA1c targets of <7%. Type 2 diabetic patients not taking any blood glucose lowering medications were administered either 15 g of D-tagatose dissolved in 125–250 ml of water three times a day or placebo with meals. Reduction in HbA1c was statistically significant compared to placebo at all post-baseline time points in the ITT population. Additionally, secondary endpoints were achieved in the ITT population with regard to LDL, total cholesterol, fasting blood glucose, and proportion of subjects achieving HbA1c targets of <7%. D-tagatose was unable to lower triglycerides or raise HDL compared to placebo. A subgroup LOCF analysis on the ITT US population showed a greater and statistically significant LS mean reduction in HbA1c in the D-tagatose group at all post-baseline visits. Based on these results it is concluded that in the ITT population D-tagatose is an effective single agent at treating many of the therapy targets of type 2 diabetes including lowering fasting blood glucose and HbA1c, and lowering of LDL and total cholesterol. PMID:27054147

New Methods for Analysis of Spatial Distribution and Coaggregation of Microbial Populations in Complex Biofilms

PubMed Central

Almstrand, Robert; Daims, Holger; Persson, Frank; Sörensson, Fred

2013-01-01

In biofilms, microbial activities form gradients of substrates and electron acceptors, creating a complex landscape of microhabitats, often resulting in structured localization of the microbial populations present. To understand the dynamic interplay between and within these populations, quantitative measurements and statistical analysis of their localization patterns within the biofilms are necessary, and adequate automated tools for such analyses are needed. We have designed and applied new methods for fluorescence in situ hybridization (FISH) and digital image analysis of directionally dependent (anisotropic) multispecies biofilms. A sequential-FISH approach allowed multiple populations to be detected in a biofilm sample. This was combined with an automated tool for vertical-distribution analysis by generating in silico biofilm slices and the recently developed Inflate algorithm for coaggregation analysis of microbial populations in anisotropic biofilms. As a proof of principle, we show distinct stratification patterns of the ammonia oxidizers Nitrosomonas oligotropha subclusters I and II and the nitrite oxidizer Nitrospira sublineage I in three different types of wastewater biofilms, suggesting niche differentiation between the N. oligotropha subclusters, which could explain their coexistence in the same biofilms. Coaggregation analysis showed that N. oligotropha subcluster II aggregated closer to Nitrospira than did N. oligotropha subcluster I in a pilot plant nitrifying trickling filter (NTF) and a moving-bed biofilm reactor (MBBR), but not in a full-scale NTF, indicating important ecophysiological differences between these phylogenetically closely related subclusters. By using high-resolution quantitative methods applicable to any multispecies biofilm in general, the ecological interactions of these complex ecosystems can be understood in more detail. PMID:23892743

77 FR 58510 - Proposed Information Collection; Comment Request; Current Population Survey (CPS), Annual Social...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-21

... various population groups. A prime statistic of interest is the classification of people in poverty and... Information Collection; Comment Request; Current Population Survey (CPS), Annual Social and Economic... conducted this supplement annually for over 50 years. The Census Bureau and the Bureau of Labor Statistics...

Powerful Inference with the D-Statistic on Low-Coverage Whole-Genome Data

PubMed Central

Soraggi, Samuele; Wiuf, Carsten; Albrechtsen, Anders

2017-01-01

The detection of ancient gene flow between human populations is an important issue in population genetics. A common tool for detecting ancient admixture events is the D-statistic. The D-statistic is based on the hypothesis of a genetic relationship that involves four populations, whose correctness is assessed by evaluating specific coincidences of alleles between the groups. When working with high-throughput sequencing data, calling genotypes accurately is not always possible; therefore, the D-statistic currently samples a single base from the reads of one individual per population. This implies ignoring much of the information in the data, an issue especially striking in the case of ancient genomes. We provide a significant improvement to overcome the problems of the D-statistic by considering all reads from multiple individuals in each population. We also apply type-specific error correction to combat the problems of sequencing errors, and show a way to correct for introgression from an external population that is not part of the supposed genetic relationship, and how this leads to an estimate of the admixture rate. We prove that the D-statistic is approximated by a standard normal distribution. Furthermore, we show that our method outperforms the traditional D-statistic in detecting admixtures. The power gain is most pronounced for low and medium sequencing depth (1–10×), and performances are as good as with perfectly called genotypes at a sequencing depth of 2×. We show the reliability of error correction in scenarios with simulated errors and ancient data, and correct for introgression in known scenarios to estimate the admixture rates. PMID:29196497

Please don't misuse the museum: 'declines' may be statistical

USGS Publications Warehouse

Grant, Evan H. Campbell

2015-01-01

Detecting declines in populations at broad spatial scales takes enormous effort, and long-term data are often more sparse than is desired for estimating trends, identifying drivers for population changes, framing conservation decisions or taking management actions. Museum records and historic data can be available at large scales across multiple decades, and are therefore an attractive source of information on the comparative status of populations. However, changes in populations may be real (e.g., in response to environmental covariates) or resulting from variation in our ability to observe the true population response (also possibly related to environmental covariates). This is a (statistical) nuisance in understanding the true status of a population. Evaluating statistical hypotheses alongside more interesting ecological ones is important in the appropriate use of museum data. Two statistical considerations are generally applicable to use of museum records: first without initial random sampling, comparison with contemporary results cannot provide inference to the entire range of a species, and second the availability of only some individuals in a population may respond to environmental changes. Changes in the availability of individuals may reduce the proportion of the population that is present and able to be counted on a given survey event, resulting in an apparent decline even when population size is stable.

Sustainable Development under Population Pressure: Lessons from Developed Land Consumption in the Conterminous U.S.

PubMed Central

2015-01-01

Population growth will result in a significant anthropogenic environmental change worldwide through increases in developed land (DL) consumption. DL consumption is an important environmental and socioeconomic process affecting humans and ecosystems. Attention has been given to DL modeling inside highly populated cities. However, modeling DL consumption should expand to non-metropolitan areas where arguably the environmental consequences are more significant. Here, we study all counties within the conterminous U.S. and based on satellite-derived product (National Land Cover Dataset 2001) we calculate the associated DL for each county. By using county population data from the 2000 census we present a comparative study on DL consumption and we propose a model linking population with expected DL consumption. Results indicate distinct geographic patterns of comparatively low and high consuming counties moving from east to west. We also demonstrate that the relationship of DL consumption with population is mostly linear, altering the notion that expected population growth will have lower DL consumption if added in counties with larger population. Added DL consumption is independent of a county’s starting population and only dependent on whether the county belongs to a Metropolitan Statistical Area (MSA). In the overlapping MSA and non-MSA population range there is also a constant DL efficiency gain of approximately 20km2 for a given population for MSA counties which suggests that transitioning from rural to urban counties has significantly higher benefits in lower populations. In addition, we analyze the socioeconomic composition of counties with extremely high or low DL consumption. High DL consumption counties have statistically lower Black/African American population, higher poverty rate and lower income per capita than average in both NMSA and MSA counties. Our analysis offers a baseline to investigate further land consumption strategies in anticipation of growing population pressures. PMID:25806525

Conservation status of polar bears (Ursus maritimus) in relation to projected sea-ice declines

NASA Astrophysics Data System (ADS)

Laidre, K. L.; Regehr, E. V.; Akcakaya, H. R.; Amstrup, S. C.; Atwood, T.; Lunn, N.; Obbard, M.; Stern, H. L., III; Thiemann, G.; Wiig, O.

2016-12-01

Loss of Arctic sea ice due to climate change is the most serious threat to polar bears (Ursus maritimus) throughout their circumpolar range. We performed a data-based sensitivity analysis with respect to this threat by evaluating the potential response of the global polar bear population to projected sea-ice conditions. We conducted 1) an assessment of generation length for polar bears, 2) developed of a standardized sea-ice metric representing important habitat characteristics for the species; and 3) performed population projections over three generations, using computer simulation and statistical models representing alternative relationships between sea ice and polar bear abundance. Using three separate approaches, the median percent change in mean global population size for polar bears between 2015 and 2050 ranged from -4% (95% CI = -62%, 50%) to -43% (95% CI = -76%, -20%). Results highlight the potential for large reductions in the global population if sea-ice loss continues. They also highlight the large amount of uncertainty in statistical projections of polar bear abundance and the sensitivity of projections to plausible alternative assumptions. The median probability of a reduction in the mean global population size of polar bears greater than 30% over three generations was approximately 0.71 (range 0.20-0.95. The median probability of a reduction greater than 50% was approximately 0.07 (range 0-0.35), and the probability of a reduction greater than 80% was negligible.

Hierarchical modeling of population stability and species group attributes from survey data

USGS Publications Warehouse

Sauer, J.R.; Link, W.A.

2002-01-01

Many ecological studies require analysis of collections of estimates. For example, population change is routinely estimated for many species from surveys such as the North American Breeding Bird Survey (BBS), and the species are grouped and used in comparative analyses. We developed a hierarchical model for estimation of group attributes from a collection of estimates of population trend. The model uses information from predefined groups of species to provide a context and to supplement data for individual species; summaries of group attributes are improved by statistical methods that simultaneously analyze collections of trend estimates. The model is Bayesian; trends are treated as random variables rather than fixed parameters. We use Markov Chain Monte Carlo (MCMC) methods to fit the model. Standard assessments of population stability cannot distinguish magnitude of trend and statistical significance of trend estimates, but the hierarchical model allows us to legitimately describe the probability that a trend is within given bounds. Thus we define population stability in terms of the probability that the magnitude of population change for a species is less than or equal to a predefined threshold. We applied the model to estimates of trend for 399 species from the BBS to estimate the proportion of species with increasing populations and to identify species with unstable populations. Analyses are presented for the collection of all species and for 12 species groups commonly used in BBS summaries. Overall, we estimated that 49% of species in the BBS have positive trends and 33 species have unstable populations. However, the proportion of species with increasing trends differs among habitat groups, with grassland birds having only 19% of species with positive trend estimates and wetland birds having 68% of species with positive trend estimates.

Detecting population-environmental interactions with mismatched time series data.

PubMed

Ferguson, Jake M; Reichert, Brian E; Fletcher, Robert J; Jager, Henriëtte I

2017-11-01

Time series analysis is an essential method for decomposing the influences of density and exogenous factors such as weather and climate on population regulation. However, there has been little work focused on understanding how well commonly collected data can reconstruct the effects of environmental factors on population dynamics. We show that, analogous to similar scale issues in spatial data analysis, coarsely sampled temporal data can fail to detect covariate effects when interactions occur on timescales that are fast relative to the survey period. We propose a method for modeling mismatched time series data that couples high-resolution environmental data to low-resolution abundance data. We illustrate our approach with simulations and by applying it to Florida's southern Snail kite population. Our simulation results show that our method can reliably detect linear environmental effects and that detecting nonlinear effects requires high-resolution covariate data even when the population turnover rate is slow. In the Snail kite analysis, our approach performed among the best in a suite of previously used environmental covariates explaining Snail kite dynamics and was able to detect a potential phenological shift in the environmental dependence of Snail kites. Our work provides a statistical framework for reliably detecting population-environment interactions from coarsely surveyed time series. An important implication of this work is that the low predictability of animal population growth by weather variables found in previous studies may be due, in part, to how these data are utilized as covariates. © 2017 by the Ecological Society of America.

Quantitative Relationship of Soil Texture with the Observed Population Density Reduction of Heterodera glycines after Annual Corn Rotation in Nebraska

PubMed Central

Pérez-Hernández, Oscar; Giesler, Loren J.

2014-01-01

Soil texture has been commonly associated with the population density of Heterodera glycines (soybean cyst nematode: SCN), but such an association has been mainly described in terms of textural classes. In this study, multivariate analysis and a generalized linear modeling approach were used to elucidate the quantitative relationship of soil texture with the observed SCN population density reduction after annual corn rotation in Nebraska. Forty-five commercial production fields were sampled in 2009, 2010, and 2011 and SCN population density (eggs/100 cm3 of soil) for each field was determined before (Pi) and after (Pf) annual corn rotation from ten 3 × 3-m sampling grids. Principal components analysis revealed that, compared with silt and clay, sand had a stronger association with SCN Pi and Pf. Cluster analysis using the average linkage method and confirmed through 1,000 bootstrap simulations identified two groups: one corresponding to predominant silt-and-clay fields and other to sand-predominant fields. This grouping suggested that SCN relative percent population decline was higher in the sandy than in the silt-and-clay predominant group. However, when groups were compared for their SCN population density reduction using Pf as the response, Pi as a covariate, and incorporating the year and field variability, a negative binomial generalized linear model indicated that the SCN population density reduction was not statistically different between the sand-predominant field group and the silt-and-clay predominant group. PMID:24987160

Analysis of Geographic and Pairwise Distances among Chinese Cashmere Goat Populations

PubMed Central

Liu, Jian-Bin; Wang, Fan; Lang, Xia; Zha, Xi; Sun, Xiao-Ping; Yue, Yao-Jing; Feng, Rui-Lin; Yang, Bo-Hui; Guo, Jian

2013-01-01

This study investigated the geographic and pairwise distances of nine Chinese local Cashmere goat populations through the analysis of 20 microsatellite DNA markers. Fluorescence PCR was used to identify the markers, which were selected based on their significance as identified by the Food and Agriculture Organization of the United Nations (FAO) and the International Society for Animal Genetics (ISAG). In total, 206 alleles were detected; the average allele number was 10.30; the polymorphism information content of loci ranged from 0.5213 to 0.7582; the number of effective alleles ranged from 4.0484 to 4.6178; the observed heterozygosity was from 0.5023 to 0.5602 for the practical sample; the expected heterozygosity ranged from 0.5783 to 0.6464; and Allelic richness ranged from 4.7551 to 8.0693. These results indicated that Chinese Cashmere goat populations exhibited rich genetic diversity. Further, the Wright’s F-statistics of subpopulation within total (FST) was 0.1184; the genetic differentiation coefficient (GST) was 0.0940; and the average gene flow (Nm) was 2.0415. All pairwise FST values among the populations were highly significant (p<0.01 or p<0.001), suggesting that the populations studied should all be considered to be separate breeds. Finally, the clustering analysis divided the Chinese Cashmere goat populations into at least four clusters, with the Hexi and Yashan goat populations alone in one cluster. These results have provided useful, practical, and important information for the future of Chinese Cashmere goat breeding. PMID:25049794

76 FR 30741 - Agency Information Collection Activities: Existing Collection; Comments Requested: Prison...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-26

... Sentenced Population Movement--National Prisoner Statistics, Extension and Revision of Existing Collection...) Title of the Form/Collection: Summary of Sentenced Population Movement--National Prisoner Statistics (3...

Using spatiotemporal statistical models to estimate animal abundance and infer ecological dynamics from survey counts

USGS Publications Warehouse

Conn, Paul B.; Johnson, Devin S.; Ver Hoef, Jay M.; Hooten, Mevin B.; London, Joshua M.; Boveng, Peter L.

2015-01-01

Ecologists often fit models to survey data to estimate and explain variation in animal abundance. Such models typically require that animal density remains constant across the landscape where sampling is being conducted, a potentially problematic assumption for animals inhabiting dynamic landscapes or otherwise exhibiting considerable spatiotemporal variation in density. We review several concepts from the burgeoning literature on spatiotemporal statistical models, including the nature of the temporal structure (i.e., descriptive or dynamical) and strategies for dimension reduction to promote computational tractability. We also review several features as they specifically relate to abundance estimation, including boundary conditions, population closure, choice of link function, and extrapolation of predicted relationships to unsampled areas. We then compare a suite of novel and existing spatiotemporal hierarchical models for animal count data that permit animal density to vary over space and time, including formulations motivated by resource selection and allowing for closed populations. We gauge the relative performance (bias, precision, computational demands) of alternative spatiotemporal models when confronted with simulated and real data sets from dynamic animal populations. For the latter, we analyze spotted seal (Phoca largha) counts from an aerial survey of the Bering Sea where the quantity and quality of suitable habitat (sea ice) changed dramatically while surveys were being conducted. Simulation analyses suggested that multiple types of spatiotemporal models provide reasonable inference (low positive bias, high precision) about animal abundance, but have potential for overestimating precision. Analysis of spotted seal data indicated that several model formulations, including those based on a log-Gaussian Cox process, had a tendency to overestimate abundance. By contrast, a model that included a population closure assumption and a scale prior on total abundance produced estimates that largely conformed to our a priori expectation. Although care must be taken to tailor models to match the study population and survey data available, we argue that hierarchical spatiotemporal statistical models represent a powerful way forward for estimating abundance and explaining variation in the distribution of dynamical populations.

Limited genetic differentiation among breeding, molting, and wintering groups of the threatened Steller's eider: The role of historic and contemporary factors

USGS Publications Warehouse

Pearce, J.M.; Talbot, S.L.; Petersen, M.R.; Rearick, J.R.

2005-01-01

Due to declines in the Alaska breeding population, the Steller's eider (Polysticta stelleri) was listed as threatened in North America in 1997. Periodic non-breeding in Russia and Alaska has hampered field-based assessments of behavioral patterns critical to recovery plans, such as levels of breeding site fidelity and movements among three regional populations: Atlantic-Russia, Pacific-Russia and Alaska. Therefore, we analyzed samples from across the species range with seven nuclear microsatellite DNA loci and cytochrome b mitochondrial (mt)DNA sequence data to infer levels of interchange among sampling areas and patterns of site fidelity. Results demonstrated low levels of population differentiation within Atlantic and Pacific nesting areas, with higher levels observed between these regions, but only for mtDNA. Bayesian analysis of microsatellite data from wintering and molting birds showed no signs of sub-population structure, even though band-recovery data suggests multiple breeding areas are present. We observed higher estimates of F-statistics for female mtDNA data versus male data, suggesting female-biased natal site fidelity. Summary statistics for mtDNA were consistent with models of historic population expansion. Lack of spatial structure in Steller's eiders may result largely from insufficient time since historic population expansions for behaviors, such as natal site fidelity, to isolate breeding areas genetically. However, other behaviors such as the periodic non-breeding observed in Steller's eiders may also play a more contemporary role in genetic homogeneity, especially for microsatellite loci. 

Women of the World: Near East and North Africa.

ERIC Educational Resources Information Center

Chamie, Mary

The third in a series of five handbooks designed to present and analyze statistical data on women in various regions of the world, this handbook focuses on women in 14 countries in the Near East and North Africa. Beginning with an overview of population distribution and changes in the region, the analysis continues with a description of women's…

Correlation-based network analysis of metabolite and enzyme profiles reveals a role of citrate biosynthesis in modulating N and C metabolism in zea mays

USDA-ARS?s Scientific Manuscript database

To investigate the natural variability of leaf metabolism and enzymatic activity in a maize inbred population, statistical and network analyses were employed on metabolite and enzyme profiles. The test of coefficient of variation showed that sugars and amino acids displayed opposite trends in their ...

The Elementary School Classroom. The Study of the Built Environment Through Student and Teacher Responses. The Elementary School and Its Population, Phase 2.

ERIC Educational Resources Information Center

Artinian, Vrej-Armen

An extensive investigation of elementary school classrooms was conducted through the collection and statistical analysis of student and teacher responses to questions concerning the educational environment. Several asepcts of the classroom are discussed, including the spatial, thermal, luminous, and aural environments. Questions were organized so…

Student Success: A Descriptive Analysis of Hispanic Students and Engagement at a Midwest Hispanic-Serving Institution

ERIC Educational Resources Information Center

Mercado, Claudia

2012-01-01

The purpose of this study was to learn more about the Hispanic students attending Northeastern Illinois University, a four-year institution in Chicago, IL, and their student success. Little is known descriptively and statistically about this population at NEIU, which serves as a Hispanic-Serving Institution. In addition, little is known about…

Flipping between Languages? An Exploratory Analysis of the Usage by Spanish-Speaking English Language Learner Tertiary Students of a Bilingual Probability Applet

ERIC Educational Resources Information Center

Lesser, Lawrence M.; Wagler, Amy E.; Salazar, Berenice

2016-01-01

English language learners (ELLs) are a rapidly growing part of the student population in many countries. Studies on resources for language learners--especially Spanish-speaking ELLs--have focused on areas such as reading, writing, and mathematics, but not introductory probability and statistics. Semi-structured qualitative interviews investigated…

A Heat Vulnerability Index and Adaptation Solutions for Pittsburgh, Pennsylvania.

PubMed

Bradford, Kathryn; Abrahams, Leslie; Hegglin, Miriam; Klima, Kelly

2015-10-06

With increasing evidence of global warming, many cities have focused attention on response plans to address their populations' vulnerabilities. Despite expected increased frequency and intensity of heat waves, the health impacts of such events in urban areas can be minimized with careful policy and economic investments. We focus on Pittsburgh, Pennsylvania and ask two questions. First, what are the top factors contributing to heat vulnerability and how do these characteristics manifest geospatially throughout Pittsburgh? Second, assuming the City wishes to deploy additional cooling centers, what placement will optimally address the vulnerability of the at risk populations? We use national census data, ArcGIS geospatial modeling, and statistical analysis to determine a range of heat vulnerability indices and optimal cooling center placement. We find that while different studies use different data and statistical calculations, all methods tested locate additional cooling centers at the confluence of the three rivers (Downtown), the northeast side of Pittsburgh (Shadyside/Highland Park), and the southeast side of Pittsburgh (Squirrel Hill). This suggests that for Pittsburgh, a researcher could apply the same factor analysis procedure to compare data sets for different locations and times; factor analyses for heat vulnerability are more robust than previously thought.

Demirjian's method in the estimation of age: A study on human third molars.

PubMed

Lewis, Amitha J; Boaz, Karen; Nagesh, K R; Srikant, N; Gupta, Neha; Nandita, K P; Manaktala, Nidhi

2015-01-01

The primary aim of the following study is to estimate the chronological age based on the stages of third molar development following the eight stages (A to H) method of Demirjian et al. (along with two modifications-Orhan) and secondary aim is to compare third molar development with sex and age. The sample consisted of 115 orthopantomograms from South Indian subjects with known chronological age and gender. Multiple regression analysis was performed with chronological age as the dependable variable and third molar root development as independent variable. All the statistical analysis was performed using the SPSS 11.0 package (IBM ® Corporation). Statistically no significant differences were found in third molar development between males and females. Depending on the available number of wisdom teeth in an individual, R (2) varied for males from 0.21 to 0.48 and for females from 0.16 to 0.38. New equations were derived for estimating the chronological age. The chronological age of a South Indian individual between 14 and 22 years may be estimated based on the regression formulae. However, additional studies with a larger study population must be conducted to meet the need for population-based information on third molar development.

Back to BaySICS: a user-friendly program for Bayesian Statistical Inference from Coalescent Simulations.

PubMed

Sandoval-Castellanos, Edson; Palkopoulou, Eleftheria; Dalén, Love

2014-01-01

Inference of population demographic history has vastly improved in recent years due to a number of technological and theoretical advances including the use of ancient DNA. Approximate Bayesian computation (ABC) stands among the most promising methods due to its simple theoretical fundament and exceptional flexibility. However, limited availability of user-friendly programs that perform ABC analysis renders it difficult to implement, and hence programming skills are frequently required. In addition, there is limited availability of programs able to deal with heterochronous data. Here we present the software BaySICS: Bayesian Statistical Inference of Coalescent Simulations. BaySICS provides an integrated and user-friendly platform that performs ABC analyses by means of coalescent simulations from DNA sequence data. It estimates historical demographic population parameters and performs hypothesis testing by means of Bayes factors obtained from model comparisons. Although providing specific features that improve inference from datasets with heterochronous data, BaySICS also has several capabilities making it a suitable tool for analysing contemporary genetic datasets. Those capabilities include joint analysis of independent tables, a graphical interface and the implementation of Markov-chain Monte Carlo without likelihoods.

A Heat Vulnerability Index and Adaptation Solutions for Pittsburgh, Pennsylvania

NASA Astrophysics Data System (ADS)

Klima, K.; Abrahams, L.; Bradford, K.; Hegglin, M.

2015-12-01

With increasing evidence of global warming, many cities have focused attention on response plans to address their populations' vulnerabilities. Despite expected increased frequency and intensity of heat waves, the health impacts of such events in urban areas can be minimized with careful policy and economic investments. We focus on Pittsburgh, Pennsylvania and ask two questions. First, what are the top factors contributing to heat vulnerability and how do these characteristics manifest geospatially throughout Pittsburgh? Second, assuming the City wishes to deploy additional cooling centers, what placement will optimally address the vulnerability of the at risk populations? We use national census data, ArcGIS geospatial modeling, and statistical analysis to determine a range of heat vulnerability indices and optimal cooling center placement. We find that while different studies use different data and statistical calculations, all methods tested locate additional cooling centers at the confluence of the three rivers (Downtown), the northeast side of Pittsburgh (Shadyside/ Highland Park), and the southeast side of Pittsburgh (Squirrel Hill). This suggests that for Pittsburgh, a researcher could apply the same factor analysis procedure to compare datasets for different locations and times; factor analyses for heat vulnerability are more robust than previously thought.

Bone age assessment in Hispanic children: digital hand atlas compared with the Greulich and Pyle (G&P) atlas

NASA Astrophysics Data System (ADS)

Fernandez, James Reza; Zhang, Aifeng; Vachon, Linda; Tsao, Sinchai

2008-03-01

Bone age assessment is most commonly performed with the use of the Greulich and Pyle (G&P) book atlas, which was developed in the 1950s. The population of theUnited States is not as homogenous as the Caucasian population in the Greulich and Pyle in the 1950s, especially in the Los Angeles, California area. A digital hand atlas (DHA) based on 1,390 hand images of children of different racial backgrounds (Caucasian, African American, Hispanic, and Asian) aged 0-18 years was collected from Children's Hospital Los Angeles. Statistical analysis discovered significant discrepancies exist between Hispanic and the G&P atlas standard. To validate the usage of DHA as a clinical standard, diagnostic radiologists performed reads on Hispanic pediatric hand and wrist computed radiography images using either the G&P pediatric radiographic atlas or the Children's Hospital Los Angeles Digital Hand Atlas (DHA) as reference. The order in which the atlas is used (G&P followed by DHA or vice versa) for each image was prepared before actual reading begins. Statistical analysis of the results was then performed to determine if a discrepancy exists between the two readings.

2015 TRI National Analysis: Toxics Release Inventory Releases at Various Summary Levels

EPA Pesticide Factsheets

The TRI National Analysis is EPA's annual interpretation of TRI data at various summary levels. It highlights how toxic chemical wastes were managed, where toxic chemicals were released and how the 2015 TRI data compare to data from previous years. This dataset reports US state, county, large aquatic ecosystem, metro/micropolitan statistical area, and facility level statistics from 2015 TRI releases, including information on: number of 2015 TRI facilities in the geographic area and their releases (total, water, air, land); population information, including populations living within 1 mile of TRI facilities (total, minority, in poverty); and Risk Screening Environmental Indicators (RSEI) model related pounds, toxicity-weighted pounds, and RSEI score. The source of administrative boundary data is the 2013 cartographic boundary shapefiles. Location of facilities is provided by EPA's Facility Registry Service (FRS). Large Aquatic Ecosystems boundaries were dissolved from the hydrologic unit boundaries and codes for the United States, Puerto Rico, and the U.S. Virgin Islands. It was revised for inclusion in the National Atlas of the United States of America (November 2002), and updated to match the streams file created by the USGS National Mapping Division (NMD) for the National Atlas of the United States of America.