Immunophenotype Discovery, Hierarchical Organization, and Template-Based Classification of Flow Cytometry Samples

DOE PAGES

Azad, Ariful; Rajwa, Bartek; Pothen, Alex

2016-08-31

We describe algorithms for discovering immunophenotypes from large collections of flow cytometry samples and using them to organize the samples into a hierarchy based on phenotypic similarity. The hierarchical organization is helpful for effective and robust cytometry data mining, including the creation of collections of cell populations’ characteristic of different classes of samples, robust classification, and anomaly detection. We summarize a set of samples belonging to a biological class or category with a statistically derived template for the class. Whereas individual samples are represented in terms of their cell populations (clusters), a template consists of generic meta-populations (a group ofmore » homogeneous cell populations obtained from the samples in a class) that describe key phenotypes shared among all those samples. We organize an FC data collection in a hierarchical data structure that supports the identification of immunophenotypes relevant to clinical diagnosis. A robust template-based classification scheme is also developed, but our primary focus is in the discovery of phenotypic signatures and inter-sample relationships in an FC data collection. This collective analysis approach is more efficient and robust since templates describe phenotypic signatures common to cell populations in several samples while ignoring noise and small sample-specific variations. We have applied the template-based scheme to analyze several datasets, including one representing a healthy immune system and one of acute myeloid leukemia (AML) samples. The last task is challenging due to the phenotypic heterogeneity of the several subtypes of AML. However, we identified thirteen immunophenotypes corresponding to subtypes of AML and were able to distinguish acute promyelocytic leukemia (APL) samples with the markers provided. Clinically, this is helpful since APL has a different treatment regimen from other subtypes of AML. Core algorithms used in our data analysis are available in the flowMatch package at www.bioconductor.org. It has been downloaded nearly 6,000 times since 2014.« less

Immunophenotype Discovery, Hierarchical Organization, and Template-Based Classification of Flow Cytometry Samples

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

Azad, Ariful; Rajwa, Bartek; Pothen, Alex

We describe algorithms for discovering immunophenotypes from large collections of flow cytometry samples and using them to organize the samples into a hierarchy based on phenotypic similarity. The hierarchical organization is helpful for effective and robust cytometry data mining, including the creation of collections of cell populations’ characteristic of different classes of samples, robust classification, and anomaly detection. We summarize a set of samples belonging to a biological class or category with a statistically derived template for the class. Whereas individual samples are represented in terms of their cell populations (clusters), a template consists of generic meta-populations (a group ofmore » homogeneous cell populations obtained from the samples in a class) that describe key phenotypes shared among all those samples. We organize an FC data collection in a hierarchical data structure that supports the identification of immunophenotypes relevant to clinical diagnosis. A robust template-based classification scheme is also developed, but our primary focus is in the discovery of phenotypic signatures and inter-sample relationships in an FC data collection. This collective analysis approach is more efficient and robust since templates describe phenotypic signatures common to cell populations in several samples while ignoring noise and small sample-specific variations. We have applied the template-based scheme to analyze several datasets, including one representing a healthy immune system and one of acute myeloid leukemia (AML) samples. The last task is challenging due to the phenotypic heterogeneity of the several subtypes of AML. However, we identified thirteen immunophenotypes corresponding to subtypes of AML and were able to distinguish acute promyelocytic leukemia (APL) samples with the markers provided. Clinically, this is helpful since APL has a different treatment regimen from other subtypes of AML. Core algorithms used in our data analysis are available in the flowMatch package at www.bioconductor.org. It has been downloaded nearly 6,000 times since 2014.« less

What a drop can do: dried blood spots as a minimally invasive method for integrating biomarkers into population-based research.

PubMed

McDade, Thomas W; Williams, Sharon; Snodgrass, J Josh

2007-11-01

Logistical constraints associated with the collection and analysis of biological samples in community-based settings have been a significant impediment to integrative, multilevel bio-demographic and biobehavioral research. However recent methodological developments have overcome many of these constraints and have also expanded the options for incorporating biomarkers into population-based health research in international as well as domestic contexts. In particular using dried blood spot (DBS) samples-drops of whole blood collected on filter paper from a simple finger prick-provides a minimally invasive method for collecting blood samples in nonclinical settings. After a brief discussion of biomarkers more generally, we review procedures for collecting, handling, and analyzing DBS samples. Advantages of using DBS samples-compared with venipuncture include the relative ease and low cost of sample collection, transport, and storage. Disadvantages include requirements for assay development and validation as well as the relatively small volumes of sample. We present the results of a comprehensive literature review of published protocols for analysis of DBS samples, and we provide more detailed analysis of protocols for 45 analytes likely to be of particular relevance to population-level health research. Our objective is to provide investigators with the information they need to make informed decisions regarding the appropriateness of blood spot methods for their research interests.

Reasons for quitting: intrinsic and extrinsic motivation for smoking cessation in a population-based sample of smokers.

PubMed

Curry, S J; Grothaus, L; McBride, C

1997-01-01

An intrinsic-extrinsic model of motivation for smoking cessation is extended to a population-based sample of smokers (N = 1,137), using a previously validated Reasons for Quitting (RFQ) scale. Psychometric evaluation of the RFQ replicated the model that includes health concerns and self-control as intrinsic motivation dimensions and immediate reinforcement and social influence as extrinsic motivation dimensions. Compared to volunteers, the population-based sample of smokers reported equivalent health concerns, lower self-control, and higher social influence motivation for cessation. Within the population-based sample, women compared to men were less motivated to quit by health concerns and more motivated by immediate reinforcement; smokers above age 55 expressed lower health concerns and higher self-control motivation than smokers below age 55. Higher baseline levels of intrinsic relative to extrinsic motivation were associated with more advanced stages of readiness to quit smoking and successful smoking cessation at a 12-month follow-up. Among continuing smokers, improvement in stage of readiness to quit over time was associated with significant increases in health concerns and self-control motivation.

Adaptive web sampling.

PubMed

Thompson, Steven K

2006-12-01

A flexible class of adaptive sampling designs is introduced for sampling in network and spatial settings. In the designs, selections are made sequentially with a mixture distribution based on an active set that changes as the sampling progresses, using network or spatial relationships as well as sample values. The new designs have certain advantages compared with previously existing adaptive and link-tracing designs, including control over sample sizes and of the proportion of effort allocated to adaptive selections. Efficient inference involves averaging over sample paths consistent with the minimal sufficient statistic. A Markov chain resampling method makes the inference computationally feasible. The designs are evaluated in network and spatial settings using two empirical populations: a hidden human population at high risk for HIV/AIDS and an unevenly distributed bird population.

Sample allocation balancing overall representativeness and stratum precision.

PubMed

Diaz-Quijano, Fredi Alexander

2018-05-07

In large-scale surveys, it is often necessary to distribute a preset sample size among a number of strata. Researchers must make a decision between prioritizing overall representativeness or precision of stratum estimates. Hence, I evaluated different sample allocation strategies based on stratum size. The strategies evaluated herein included allocation proportional to stratum population; equal sample for all strata; and proportional to the natural logarithm, cubic root, and square root of the stratum population. This study considered the fact that, from a preset sample size, the dispersion index of stratum sampling fractions is correlated with the population estimator error and the dispersion index of stratum-specific sampling errors would measure the inequality in precision distribution. Identification of a balanced and efficient strategy was based on comparing those both dispersion indices. Balance and efficiency of the strategies changed depending on overall sample size. As the sample to be distributed increased, the most efficient allocation strategies were equal sample for each stratum; proportional to the logarithm, to the cubic root, to square root; and that proportional to the stratum population, respectively. Depending on sample size, each of the strategies evaluated could be considered in optimizing the sample to keep both overall representativeness and stratum-specific precision. Copyright © 2018 Elsevier Inc. All rights reserved.

STX--Fortran-4 program for estimates of tree populations from 3P sample-tree-measurements

Treesearch

L. R. Grosenbaugh

1967-01-01

Describes how to use an improved and greatly expanded version of an earlier computer program (1964) that converts dendrometer measurements of 3P-sample trees to population values in terms of whatever units user desires. Many new options are available, including that of obtaining a product-yield and appraisal report based on regression coefficients supplied by user....

[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.

Estimating Kinship in Admixed Populations

PubMed Central

Thornton, Timothy; Tang, Hua; Hoffmann, Thomas J.; Ochs-Balcom, Heather M.; Caan, Bette J.; Risch, Neil

2012-01-01

Genome-wide association studies (GWASs) are commonly used for the mapping of genetic loci that influence complex traits. A problem that is often encountered in both population-based and family-based GWASs is that of identifying cryptic relatedness and population stratification because it is well known that failure to appropriately account for both pedigree and population structure can lead to spurious association. A number of methods have been proposed for identifying relatives in samples from homogeneous populations. A strong assumption of population homogeneity, however, is often untenable, and many GWASs include samples from structured populations. Here, we consider the problem of estimating relatedness in structured populations with admixed ancestry. We propose a method, REAP (relatedness estimation in admixed populations), for robust estimation of identity by descent (IBD)-sharing probabilities and kinship coefficients in admixed populations. REAP appropriately accounts for population structure and ancestry-related assortative mating by using individual-specific allele frequencies at SNPs that are calculated on the basis of ancestry derived from whole-genome analysis. In simulation studies with related individuals and admixture from highly divergent populations, we demonstrate that REAP gives accurate IBD-sharing probabilities and kinship coefficients. We apply REAP to the Mexican Americans in Los Angeles, California (MXL) population sample of release 3 of phase III of the International Haplotype Map Project; in this sample, we identify third- and fourth-degree relatives who have not previously been reported. We also apply REAP to the African American and Hispanic samples from the Women's Health Initiative SNP Health Association Resource (WHI-SHARe) study, in which hundreds of pairs of cryptically related individuals have been identified. PMID:22748210

Sex estimation in a modern American osteological sample using a discriminant function analysis from the calcaneus.

PubMed

DiMichele, Daniel L; Spradley, M Katherine

2012-09-10

Reliable methods for sex estimation during the development of a biological profile are important to the forensic community in instances when the common skeletal elements used to assess sex are absent or damaged. Sex estimation from the calcaneus has potentially significant importance for the forensic community. Specifically, measurements of the calcaneus provide an additional reliable method for sex estimation via discriminant function analysis based on a North American forensic population. Research on a modern American sample was chosen in order to develop up-to-date population specific discriminant functions for sex estimation. The current study addresses this matter, building upon previous research and introduces a new measurement, posterior circumference that promises to advance the accuracy of use of this single, highly resistant bone in future instances of sex determination from partial skeletal remains. Data were collected from The William Bass Skeletal Collection, housed at The University of Tennessee. Sample size includes 320 adult individuals born between the years 1900 and 1985. The sample was comprised of 136 females and 184 males. Skeletons used for measurements were confined to those with fused diaphyses showing no signs of pathology or damage that may have altered measurements, and that also had accompanying records that included information on ancestry, age, and sex. Measurements collected and analyzed include maximum length, load-arm length, load-arm width, and posterior circumference. The sample was used to compute a discriminant function, based on all four variables, and was performed in SAS 9.1.3. The discriminant function obtained an overall cross-validated classification rate of 86.69%. Females were classified correctly in 88.64% of the cases and males were correctly classified in 84.75% of the cases. Due to the increasing heterogeneity of current populations further discussion on this topic will include the importance that the re-evaluation of past studies has on modern forensic populations. Due to secular and micro evolutionary changes among populations, the near future must include additional methods being updated, and new methods being examined, both which should cover a wide population spectrum. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Methods of Suicide among Cancer Patients: A Nationwide Population-Based Study

ERIC Educational Resources Information Center

Chung, Kuo-Hsuan; Lin, Herng-Ching

2010-01-01

A 3-year nationwide population-based data set was used to explore methods of suicide (violent vs. nonviolent) and possible contributing factors among cancer patients in Taiwan. A total of 1,065 cancer inpatients who committed suicide were included as our study sample. The regression shows that those who had genitourinary cancer were 0.55 times (p…

Socioeconomic Status and the Risk of Suspected Autism Spectrum Disorders among 18-Month-Old Toddlers in Japan: A Population-Based Study

ERIC Educational Resources Information Center

Fujiwara, Takeo

2014-01-01

The association between family socioeconomic status (SES) and the suspected autism spectrum disorder (ASD) status of 18-month-old toddlers was investigated using a population-based sample in Japan, which has a universal healthcare system and a mandatory health checkup system for toddlers. Questionnaires including SES measurements and modified…

Advancing Methods for U.S. Transgender Health Research

PubMed Central

Reisner, Sari L.; Deutsch, Madeline B.; Bhasin, Shalender; Bockting, Walter; Brown, George R.; Feldman, Jamie; Garofalo, Rob; Kreukels, Baudewijntje; Radix, Asa; Safer, Joshua D.; Tangpricha, Vin; T’Sjoen, Guy; Goodman, Michael

2016-01-01

Purpose of Review To describe methodological challenges, gaps, and opportunities in U.S. transgender health research. Recent Findings Lack of large prospective observational studies and intervention trials, limited data on risks and benefits of gender affirmation (e.g., hormones and surgical interventions), and inconsistent use of definitions across studies hinder evidence-based care for transgender people. Systematic high-quality observational and intervention-testing studies may be carried out using several approaches, including general population-based, health systems-based, clinic-based, venue-based, and hybrid designs. Each of these approaches has its strength and limitations; however, harmonization of research efforts is needed. Ongoing development of evidence-based clinical recommendations will benefit from a series of observational and intervention studies aimed at identification, recruitment, and follow-up of transgender people of different ages, from different racial, ethnic, and socioeconomic backgrounds and with diverse gender identities. Summary Transgender health research faces challenges that include standardization of lexicon, agreed-upon population definitions, study design, sampling, measurement, outcome ascertainment, and sample size. Application of existing and new methods is needed to fill existing gaps, increase the scientific rigor and reach of transgender health research, and inform evidence-based prevention and care for this underserved population. PMID:26845331

[New population curves in spanish extremely preterm neonates].

PubMed

García-Muñoz Rodrigo, F; García-Alix Pérez, A; Figueras Aloy, J; Saavedra Santana, P

2014-08-01

Most anthropometric reference data for extremely preterm infants used in Spain are outdated and based on non-Spanish populations, or are derived from small hospital-based samples that failed to include neonates of borderline viability. To develop gender-specific, population-based curves for birth weight, length, and head circumference in extremely preterm Caucasian infants, using a large contemporary sample size of Spanish singletons. Anthropometric data from neonates ≤ 28 weeks of gestational age were collected between January 2002 and December 2010 using the Spanish database SEN1500. Gestational age was estimated according to obstetric data (early pregnancy ultrasound). The data were analyzed with the SPSS.20 package, and centile tables were created for males and females using the Cole and Green LMS method. This study presents the first population-based growth curves for extremely preterm infants, including those of borderline viability, in Spain. A sexual dimorphism is evident for all of the studied parameters, starting at early gestation. These new gender-specific and population-based data could be useful for the improvement of growth assessments of extremely preterm infants in our country, for the development of epidemiological studies, for the evaluation of temporal trends, and for clinical or public health interventions seeking to optimize fetal growth. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

78 FR 54253 - Proposed Data Collections Submitted for Public Comment and Recommendations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-03

... every level of the social ecology, including individuals, families, and communities, and thus have the... effective population-based prevention strategies. Approximately 188 Colorado state and county employees and partners form the sample population. Specifically, state- and county-level employees working in welfare and...

Fine-scaled human genetic structure revealed by SNP microarrays.

PubMed

Xing, Jinchuan; Watkins, W Scott; Witherspoon, David J; Zhang, Yuhua; Guthery, Stephen L; Thara, Rangaswamy; Mowry, Bryan J; Bulayeva, Kazima; Weiss, Robert B; Jorde, Lynn B

2009-05-01

We report an analysis of more than 240,000 loci genotyped using the Affymetrix SNP microarray in 554 individuals from 27 worldwide populations in Africa, Asia, and Europe. To provide a more extensive and complete sampling of human genetic variation, we have included caste and tribal samples from two states in South India, Daghestanis from eastern Europe, and the Iban from Malaysia. Consistent with observations made by Charles Darwin, our results highlight shared variation among human populations and demonstrate that much genetic variation is geographically continuous. At the same time, principal components analyses reveal discernible genetic differentiation among almost all identified populations in our sample, and in most cases, individuals can be clearly assigned to defined populations on the basis of SNP genotypes. All individuals are accurately classified into continental groups using a model-based clustering algorithm, but between closely related populations, genetic and self-classifications conflict for some individuals. The 250K data permitted high-level resolution of genetic variation among Indian caste and tribal populations and between highland and lowland Daghestani populations. In particular, upper-caste individuals from Tamil Nadu and Andhra Pradesh form one defined group, lower-caste individuals from these two states form another, and the tribal Irula samples form a third. Our results emphasize the correlation of genetic and geographic distances and highlight other elements, including social factors that have contributed to population structure.

Evaluation of respondent-driven sampling.

PubMed

McCreesh, Nicky; Frost, Simon D W; Seeley, Janet; Katongole, Joseph; Tarsh, Matilda N; Ndunguse, Richard; Jichi, Fatima; Lunel, Natasha L; Maher, Dermot; Johnston, Lisa G; Sonnenberg, Pam; Copas, Andrew J; Hayes, Richard J; White, Richard G

2012-01-01

Respondent-driven sampling is a novel variant of link-tracing sampling for estimating the characteristics of hard-to-reach groups, such as HIV prevalence in sex workers. Despite its use by leading health organizations, the performance of this method in realistic situations is still largely unknown. We evaluated respondent-driven sampling by comparing estimates from a respondent-driven sampling survey with total population data. Total population data on age, tribe, religion, socioeconomic status, sexual activity, and HIV status were available on a population of 2402 male household heads from an open cohort in rural Uganda. A respondent-driven sampling (RDS) survey was carried out in this population, using current methods of sampling (RDS sample) and statistical inference (RDS estimates). Analyses were carried out for the full RDS sample and then repeated for the first 250 recruits (small sample). We recruited 927 household heads. Full and small RDS samples were largely representative of the total population, but both samples underrepresented men who were younger, of higher socioeconomic status, and with unknown sexual activity and HIV status. Respondent-driven sampling statistical inference methods failed to reduce these biases. Only 31%-37% (depending on method and sample size) of RDS estimates were closer to the true population proportions than the RDS sample proportions. Only 50%-74% of respondent-driven sampling bootstrap 95% confidence intervals included the population proportion. Respondent-driven sampling produced a generally representative sample of this well-connected nonhidden population. However, current respondent-driven sampling inference methods failed to reduce bias when it occurred. Whether the data required to remove bias and measure precision can be collected in a respondent-driven sampling survey is unresolved. Respondent-driven sampling should be regarded as a (potentially superior) form of convenience sampling method, and caution is required when interpreting findings based on the sampling method.

Dietary Behaviors of a Racially and Ethnically Diverse Sample of Overweight and Obese Californians

ERIC Educational Resources Information Center

Sorkin, Dara H.; Billimek, John

2012-01-01

Objectives: To examine racial/ethnic differences in the dietary behaviors of overweight or obese adults using the 2007 California Health Interview Survey. Method: Data were obtained from the 2007 California Health Interview Survey, a population-based sample of noninstitutionalized adults in California. The sample included 26,721 adults aged 18…

Cancer incidence among HIV-positive women in British Columbia, Canada: Heightened risk of virus-related malignancies.

PubMed

Salters, K A; Cescon, A; Zhang, W; Ogilvie, G; Murray, M C M; Coldman, A; Hamm, J; Chiu, C G; Montaner, J S G; Wiseman, S M; Money, D; Pick, N; Hogg, R S

2016-03-01

We used population-based data to identify incident cancer cases and correlates of cancer among women living with HIV/AIDS in British Columbia (BC), Canada between 1994 and 2008. Data were obtained from a retrospective population-based cohort created from linkage of two province-wide databases: (1) the database of the BC Cancer Agency, a province-wide population-based cancer registry, and (2) a database managed by the BC Centre for Excellence in HIV/AIDS, which contains data on all persons treated with antiretroviral therapy in BC. This analysis included women (≥ 19 years old) living with HIV in BC, Canada. Incident cancer diagnoses that occurred after highly active antiretroviral therapy (HAART) initiation were included. We obtained a general population comparison of cancer incidence among women from the BC Cancer Agency. Bivariate analysis (Pearson χ(2) , Fisher's exact or Wilcoxon rank-sum test) compared women with and without incident cancer across relevant clinical and sociodemographic variables. Standardized incidence ratios (SIRs) were calculated for selected cancers compared with the general population sample. We identified 2211 women with 12 529 person-years (PY) of follow-up who were at risk of developing cancer after HAART initiation. A total of 77 incident cancers (615/100 000 PY) were identified between 1994 and 2008. HIV-positive women with cancer, in comparison to the general population sample, were more likely to be diagnosed with invasive cervical cancer, Hodgkin's lymphoma, non-Hodgkin's lymphoma and Kaposi's sarcoma and less likely to be diagnosed with cancers of the digestive system. This study observed elevated rates of cancer among HIV-positive women compared to a general population sample. HIV-positive women may have an increased risk for cancers of viral-related pathogenesis. © 2015 British HIV Association.

Robust inference of population structure for ancestry prediction and correction of stratification in the presence of relatedness.

PubMed

Conomos, Matthew P; Miller, Michael B; Thornton, Timothy A

2015-05-01

Population structure inference with genetic data has been motivated by a variety of applications in population genetics and genetic association studies. Several approaches have been proposed for the identification of genetic ancestry differences in samples where study participants are assumed to be unrelated, including principal components analysis (PCA), multidimensional scaling (MDS), and model-based methods for proportional ancestry estimation. Many genetic studies, however, include individuals with some degree of relatedness, and existing methods for inferring genetic ancestry fail in related samples. We present a method, PC-AiR, for robust population structure inference in the presence of known or cryptic relatedness. PC-AiR utilizes genome-screen data and an efficient algorithm to identify a diverse subset of unrelated individuals that is representative of all ancestries in the sample. The PC-AiR method directly performs PCA on the identified ancestry representative subset and then predicts components of variation for all remaining individuals based on genetic similarities. In simulation studies and in applications to real data from Phase III of the HapMap Project, we demonstrate that PC-AiR provides a substantial improvement over existing approaches for population structure inference in related samples. We also demonstrate significant efficiency gains, where a single axis of variation from PC-AiR provides better prediction of ancestry in a variety of structure settings than using 10 (or more) components of variation from widely used PCA and MDS approaches. Finally, we illustrate that PC-AiR can provide improved population stratification correction over existing methods in genetic association studies with population structure and relatedness. © 2015 WILEY PERIODICALS, INC.

Profiling the mobile-only population in Australia: insights from the Australian National Health Survey.

PubMed

Baffour, Bernard; Haynes, Michele; Dinsdale, Shane; Western, Mark; Pennay, Darren

2016-10-01

The Australian population that relies on mobile phones exclusively has increased from 5% in 2005 to 29% in 2014. Failing to include this mobile-only population leads to a potential bias in estimates from landline-based telephone surveys. This paper considers the impacts on selected health prevalence estimates with and without the mobile-only population. Using data from the Australian Health Survey - which, for the first time, included a question on telephone status - we examined demographic, geographic and health differences between the landline-accessible and mobile-only population. These groups were also compared to the full population, controlling for the sampling design and differential non-response patterns in the observed sample through weighting and benchmarking. The landline-accessible population differs from the mobile-only population for selected health measures resulting in biased prevalence estimates for smoking, alcohol risk and private health insurance coverage in the full population. The differences remain even after adjusting for age and gender. Using landline telephones only for conducting population health surveys will have an impact on prevalence rate estimates of health risk factors due to the differing profiles of the mobile-only population from the landline-accessible population. © 2016 Public Health Association of Australia.

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.

Inventory implications of using sampling variances in estimation of growth model coefficients

Treesearch

Albert R. Stage; William R. Wykoff

2000-01-01

Variables based on stand densities or stocking have sampling errors that depend on the relation of tree size to plot size and on the spatial structure of the population, ignoring the sampling errors of such variables, which include most measures of competition used in both distance-dependent and distance-independent growth models, can bias the predictions obtained from...

A two-stage cluster sampling method using gridded population data, a GIS, and Google Earth(TM) imagery in a population-based mortality survey in Iraq.

PubMed

Galway, Lp; Bell, Nathaniel; Sae, Al Shatari; Hagopian, Amy; Burnham, Gilbert; Flaxman, Abraham; Weiss, Wiliam M; Rajaratnam, Julie; Takaro, Tim K

2012-04-27

Mortality estimates can measure and monitor the impacts of conflict on a population, guide humanitarian efforts, and help to better understand the public health impacts of conflict. Vital statistics registration and surveillance systems are rarely functional in conflict settings, posing a challenge of estimating mortality using retrospective population-based surveys. We present a two-stage cluster sampling method for application in population-based mortality surveys. The sampling method utilizes gridded population data and a geographic information system (GIS) to select clusters in the first sampling stage and Google Earth TM imagery and sampling grids to select households in the second sampling stage. The sampling method is implemented in a household mortality study in Iraq in 2011. Factors affecting feasibility and methodological quality are described. Sampling is a challenge in retrospective population-based mortality studies and alternatives that improve on the conventional approaches are needed. The sampling strategy presented here was designed to generate a representative sample of the Iraqi population while reducing the potential for bias and considering the context specific challenges of the study setting. This sampling strategy, or variations on it, are adaptable and should be considered and tested in other conflict settings.

A two-stage cluster sampling method using gridded population data, a GIS, and Google EarthTM imagery in a population-based mortality survey in Iraq

PubMed Central

2012-01-01

Background Mortality estimates can measure and monitor the impacts of conflict on a population, guide humanitarian efforts, and help to better understand the public health impacts of conflict. Vital statistics registration and surveillance systems are rarely functional in conflict settings, posing a challenge of estimating mortality using retrospective population-based surveys. Results We present a two-stage cluster sampling method for application in population-based mortality surveys. The sampling method utilizes gridded population data and a geographic information system (GIS) to select clusters in the first sampling stage and Google Earth TM imagery and sampling grids to select households in the second sampling stage. The sampling method is implemented in a household mortality study in Iraq in 2011. Factors affecting feasibility and methodological quality are described. Conclusion Sampling is a challenge in retrospective population-based mortality studies and alternatives that improve on the conventional approaches are needed. The sampling strategy presented here was designed to generate a representative sample of the Iraqi population while reducing the potential for bias and considering the context specific challenges of the study setting. This sampling strategy, or variations on it, are adaptable and should be considered and tested in other conflict settings. PMID:22540266

Minimal-assumption inference from population-genomic data

NASA Astrophysics Data System (ADS)

Weissman, Daniel; Hallatschek, Oskar

Samples of multiple complete genome sequences contain vast amounts of information about the evolutionary history of populations, much of it in the associations among polymorphisms at different loci. Current methods that take advantage of this linkage information rely on models of recombination and coalescence, limiting the sample sizes and populations that they can analyze. We introduce a method, Minimal-Assumption Genomic Inference of Coalescence (MAGIC), that reconstructs key features of the evolutionary history, including the distribution of coalescence times, by integrating information across genomic length scales without using an explicit model of recombination, demography or selection. Using simulated data, we show that MAGIC's performance is comparable to PSMC' on single diploid samples generated with standard coalescent and recombination models. More importantly, MAGIC can also analyze arbitrarily large samples and is robust to changes in the coalescent and recombination processes. Using MAGIC, we show that the inferred coalescence time histories of samples of multiple human genomes exhibit inconsistencies with a description in terms of an effective population size based on single-genome data.

Restitution and genetic differentiation of salmon populations in the southern Baltic genotyped with the Atlantic salmon 7K SNP array.

PubMed

Poćwierz-Kotus, Anita; Bernaś, Rafał; Kent, Matthew P; Lien, Sigbjørn; Leliűna, Egidijus; Dębowski, Piotr; Wenne, Roman

2015-05-06

Native populations of Atlantic salmon in Poland, from the southern Baltic region, became extinct in the 1980s. Attempts to restitute salmon populations in Poland have been based on a Latvian salmon population from the Daugava river. Releases of hatchery reared smolts started in 1986, but to date, only one population with confirmed natural reproduction has been observed in the Slupia river. Our aim was to investigate the genetic differentiation of salmon populations in the southern Baltic using a 7K SNP (single nucleotide polymorphism) array in order to assess the impact of salmon restitution in Poland. One hundred and forty salmon samples were collected from: the Polish Slupia river including wild salmon and individuals from two hatcheries, the Swedish Morrum river and the Lithuanian Neman river. All samples were genotyped using an Atlantic salmon 7K SNP array. A set of 3218 diagnostic SNPs was used for genetic analyses. Genetic structure analyses indicated that the individuals from the investigated populations were clustered into three groups i.e. one clade that included individuals from both hatcheries and the wild population from the Polish Slupia river, which was clearly separated from the other clades. An assignment test showed that there were no stray fish from the Morrum or Neman rivers in the sample analyzed from the Slupia river. Global FST over polymorphic loci was high (0.177). A strong genetic differentiation was observed between the Lithuanian and Swedish populations (FST = 0.28). Wild juvenile salmon specimens that were sampled from the Slupia river were the progeny of fish released from hatcheries and, most likely, were not progeny of stray fish from Sweden or Lithuania. Strong genetic differences were observed between the salmon populations from the three studied locations. Our recommendation is that future stocking activities that aim at restituting salmon populations in Poland include stocking material from the Lithuanian Neman river because of its closer geographic proximity.

Tissues from population-based cancer registries: a novel approach to increasing research potential.

PubMed

Goodman, Marc T; Hernandez, Brenda Y; Hewitt, Stephen; Lynch, Charles F; Coté, Timothy R; Frierson, Henry F; Moskaluk, Christopher A; Killeen, Jeffrey L; Cozen, Wendy; Key, Charles R; Clegg, Limin; Reichman, Marsha; Hankey, Benjamin F; Edwards, Brenda

2005-07-01

Population-based cancer registries, such as those included in the Surveillance, Epidemiology, and End-Results (SEER) Program, offer tremendous research potential beyond traditional surveillance activities. We describe the expansion of SEER registries to gather formalin-fixed, paraffin-embedded tissue from cancer patients on a population basis. Population-based tissue banks have the advantage of providing an unbiased sampling frame for evaluating the public health impact of genes or protein targets that may be used for therapeutic or diagnostic purposes in defined communities. Such repositories provide a unique resource for testing new molecular classification schemes for cancer, validating new biologic markers of malignancy, prognosis and progression, assessing therapeutic targets, and measuring allele frequencies of cancer-associated genetic polymorphisms or germline mutations in representative samples. The assembly of tissue microarrays will allow for the use of rapid, large-scale protein-expression profiling of tumor samples while limiting depletion of this valuable resource. Access to biologic specimens through SEER registries will provide researchers with demographic, clinical, and risk factor information on cancer patients with assured data quality and completeness. Clinical outcome data, such as disease-free survival, can be correlated with previously validated prognostic markers. Furthermore, the anonymity of the study subject can be protected through rigorous standards of confidentiality. SEER-based tissue resources represent a step forward in true, population-based tissue repositories of tumors from US patients and may serve as a foundation for molecular epidemiology studies of cancer in this country.

Approaches to Recruiting 'Hard-To-Reach' Populations into Re-search: A Review of the Literature.

PubMed

Shaghaghi, Abdolreza; Bhopal, Raj S; Sheikh, Aziz

2011-01-01

'Hard-to-reach' is a term used to describe those sub-groups of the population that may be difficult to reach or involve in research or public health programmes. Application of a single term to call these sub-sections of populations implies a homogeneity within distinct groups, which does not necessarily exist. Different sampling techniques were introduced so far to recruit hard-to-reach populations. In this article, we have reviewed a range of ap-proaches that have been used to widen participation in studies. We performed a Pubmed and Google search for relevant English language articles using the keywords and phrases: (hard-to-reach AND population* OR sampl*), (hidden AND population* OR sample*) and ("hard to reach" AND population* OR sample*) and a consul-tation of the retrieved articles' bibliographies to extract empirical evidence from publications that discussed or examined the use of sampling techniques to recruit hidden or hard-to-reach populations in health studies. Reviewing the literature has identified a range of techniques to recruit hard-to-reach populations, including snowball sampling, respondent-driven sampling (RDS), indigenous field worker sampling (IFWS), facility-based sampling (FBS), targeted sampling (TS), time-location (space) sampling (TLS), conventional cluster sampling (CCS) and capture re-capture sampling (CR). The degree of compliance with a study by a certain 'hard-to-reach' group de-pends on the characteristics of that group, recruitment technique used and the subject of inter-est. Irrespective of potential advantages or limitations of the recruitment techniques reviewed, their successful use depends mainly upon our knowledge about specific characteristics of the target populations. Thus in line with attempts to expand the current boundaries of our know-ledge about recruitment techniques in health studies and their applications in varying situa-tions, we should also focus on possibly all contributing factors which may have an impact on participation rate within a defined population group.

Evaluation of Respondent-Driven Sampling

PubMed Central

McCreesh, Nicky; Frost, Simon; Seeley, Janet; Katongole, Joseph; Tarsh, Matilda Ndagire; Ndunguse, Richard; Jichi, Fatima; Lunel, Natasha L; Maher, Dermot; Johnston, Lisa G; Sonnenberg, Pam; Copas, Andrew J; Hayes, Richard J; White, Richard G

2012-01-01

Background Respondent-driven sampling is a novel variant of link-tracing sampling for estimating the characteristics of hard-to-reach groups, such as HIV prevalence in sex-workers. Despite its use by leading health organizations, the performance of this method in realistic situations is still largely unknown. We evaluated respondent-driven sampling by comparing estimates from a respondent-driven sampling survey with total-population data. Methods Total-population data on age, tribe, religion, socioeconomic status, sexual activity and HIV status were available on a population of 2402 male household-heads from an open cohort in rural Uganda. A respondent-driven sampling (RDS) survey was carried out in this population, employing current methods of sampling (RDS sample) and statistical inference (RDS estimates). Analyses were carried out for the full RDS sample and then repeated for the first 250 recruits (small sample). Results We recruited 927 household-heads. Full and small RDS samples were largely representative of the total population, but both samples under-represented men who were younger, of higher socioeconomic status, and with unknown sexual activity and HIV status. Respondent-driven-sampling statistical-inference methods failed to reduce these biases. Only 31%-37% (depending on method and sample size) of RDS estimates were closer to the true population proportions than the RDS sample proportions. Only 50%-74% of respondent-driven-sampling bootstrap 95% confidence intervals included the population proportion. Conclusions Respondent-driven sampling produced a generally representative sample of this well-connected non-hidden population. However, current respondent-driven-sampling inference methods failed to reduce bias when it occurred. Whether the data required to remove bias and measure precision can be collected in a respondent-driven sampling survey is unresolved. Respondent-driven sampling should be regarded as a (potentially superior) form of convenience-sampling method, and caution is required when interpreting findings based on the sampling method. PMID:22157309

Challenges to be overcome using population-based sampling methods to recruit veterans for a study of post-traumatic stress disorder and traumatic brain injury.

PubMed

Bayley, Peter J; Kong, Jennifer Y; Helmer, Drew A; Schneiderman, Aaron; Roselli, Lauren A; Rosse, Stephanie M; Jackson, Jordan A; Baldwin, Janet; Isaac, Linda; Nolasco, Michael; Blackman, Marc R; Reinhard, Matthew J; Ashford, John Wesson; Chapman, Julie C

2014-04-08

Many investigators are interested in recruiting veterans from recent conflicts in Afghanistan and Iraq with Traumatic Brain Injury (TBI) and/or Post Traumatic Stress Disorder (PTSD). Researchers pursuing such studies may experience problems in recruiting sufficient numbers unless effective strategies are used. Currently, there is very little information on recruitment strategies for individuals with TBI and/or PTSD. It is known that groups of patients with medical conditions may be less likely to volunteer for clinical research. This study investigated the feasibility of recruiting veterans returning from recent military conflicts--Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF)--using a population-based sampling method. Individuals were sampled from a previous epidemiological study. Three study sites focused on recruiting survey respondents (n = 445) who lived within a 60 mile radius of one of the sites. Overall, the successful recruitment of veterans using a population-based sampling method was dependent on the ability to contact potential participants following mass mailing. Study enrollment of participants with probable TBI and/or PTSD had a recruitment yield (enrolled/total identified) of 5.4%. We were able to contact 146 individuals, representing a contact rate of 33%. Sixty-six of the individuals contacted were screened. The major reasons for not screening included a stated lack of interest in the study (n = 37), a failure to answer screening calls after initial contact (n = 30), and an unwillingness or inability to travel to a study site (n = 10). Based on the phone screening, 36 veterans were eligible for the study. Twenty-four veterans were enrolled, (recruitment yield = 5.4%) and twelve were not enrolled for a variety of reasons. Our experience with a population-based sampling method for recruitment of recent combat veterans illustrates the challenges encountered, particularly contacting and screening potential participants. The screening and enrollment data will help guide recruitment for future studies using population-based methods.

Validation of Warwick-Edinburgh Mental Well-being Scale (WEMWBS) in a population of people using Secondary Care Mental Health Services.

PubMed

Bass, Malcolm; Dawkin, Mathew; Muncer, Steven; Vigurs, Scott; Bostock, Janet

2016-08-01

The Warwick-Edinburgh Mental Well-being Scale (WEMWBS) is a relatively new measure and to date has been validated in a number of populations, including student, general and adolescent samples across the UK. There is increasing interest in measuring the mental well-being of users of secondary care mental health services and therefore it is apt to validate WEMWBS for this population. To investigate the validity of WEMWBS in a secondary care mental health service user population. Data was collected from two NHS Trusts and one charity. Analyses are based on 1180 completed WEMWBS. WEMWBS scores for this population are significantly lower than those in a general population (Mean 34.9, SD 13.8). Overall the data analyses supported the use of WEMWBS in this population sample. The Rasch analysis found that the majority of the items can be seen as measuring one dimension. The confirmatory factor analysis supports a one factor solution and thus, measures a single underlying concept. The findings from this study show WEMWBS to be a valid and reliable measure for this population sample.

Health-Related Quality of Life and Health Behaviors in a Population-Based Sample of Older, Foreign-Born, Chinese American Adults Living in New York City

ERIC Educational Resources Information Center

Wyatt, Laura C.; Trinh-Shevrin, Chau; Islam, Nadia S.; Kwon, Simona C.

2014-01-01

Although the New York City Chinese population aged =65 years increased by 50% between 2000 and 2010, the health needs of this population are poorly understood. Approximately 3,001 Chinese individuals from high-density Asian American New York City areas were included in the REACH U.S. Risk Factor Survey; 805 (26.8%) were aged =65 years and…

Evaluating sampling designs by computer simulation: A case study with the Missouri bladderpod

USGS Publications Warehouse

Morrison, L.W.; Smith, D.R.; Young, C.; Nichols, D.W.

2008-01-01

To effectively manage rare populations, accurate monitoring data are critical. Yet many monitoring programs are initiated without careful consideration of whether chosen sampling designs will provide accurate estimates of population parameters. Obtaining accurate estimates is especially difficult when natural variability is high, or limited budgets determine that only a small fraction of the population can be sampled. The Missouri bladderpod, Lesquerella filiformis Rollins, is a federally threatened winter annual that has an aggregated distribution pattern and exhibits dramatic interannual population fluctuations. Using the simulation program SAMPLE, we evaluated five candidate sampling designs appropriate for rare populations, based on 4 years of field data: (1) simple random sampling, (2) adaptive simple random sampling, (3) grid-based systematic sampling, (4) adaptive grid-based systematic sampling, and (5) GIS-based adaptive sampling. We compared the designs based on the precision of density estimates for fixed sample size, cost, and distance traveled. Sampling fraction and cost were the most important factors determining precision of density estimates, and relative design performance changed across the range of sampling fractions. Adaptive designs did not provide uniformly more precise estimates than conventional designs, in part because the spatial distribution of L. filiformis was relatively widespread within the study site. Adaptive designs tended to perform better as sampling fraction increased and when sampling costs, particularly distance traveled, were taken into account. The rate that units occupied by L. filiformis were encountered was higher for adaptive than for conventional designs. Overall, grid-based systematic designs were more efficient and practically implemented than the others. ?? 2008 The Society of Population Ecology and Springer.

Predictive equations for total lung capacity and residual volume calculated from radiographs in a random sample of the Michigan population.

PubMed Central

Kilburn, K H; Warshaw, R H; Thornton, J C; Thornton, K; Miller, A

1992-01-01

BACKGROUND: Published predicted values for total lung capacity and residual volume are often based on a small number of subjects and derive from different populations from predicted spirometric values. Equations from the only two large studies gave smaller predicted values for total lung capacity than the smaller studies. A large number of subjects have been studied from a population which has already provided predicted values for spirometry and transfer factor for carbon monoxide. METHODS: Total lung capacity was measured from standard posteroanterior and lateral chest radiographs and forced vital capacity by spirometry in a population sample of 771 subjects. Prediction equations were developed for total lung capacity (TLC), residual volume (RV) and RV/TLC in two groups--normal and total. Subjects with signs or symptoms of cardiopulmonary disease were combined with the normal subjects and equations for all subjects were also modelled. RESULTS: Prediction equations for TLC and RV in non-smoking normal men and women were square root transformations which included height and weight but not age. They included a coefficient for duration of smoking in current smokers. The predictive equation for RV/TLC included weight, age, age and duration of smoking for current smokers and ex-smokers of both sexes. For the total population the equations took the same form but the height coefficients and constants were slightly different. CONCLUSION: These population based prediction equations for TLC, RV and RV/TLC provide reference standards in a population that has provided reference standards for spirometry and single breath transfer factor for carbon monoxide. PMID:1412094

Sexual Abuse among Female High School Students in Istanbul, Turkey

ERIC Educational Resources Information Center

Alikasifoglu, Mujgan; Erginoz, Ethem; Ercan, Oya; Albayrak-Kaymak, Deniz; Uysal, Omer; Ilter, Ozdemir

2006-01-01

Objective: The objective of the study was to determine the prevalence of sexual abuse in female adolescents in Istanbul, Turkey from data collected as part of a school-based population study on health and health behaviors. Method: A stratified cluster sampling procedure was used for this cross-sectional study. The study sample included 1,955…

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

ERIC Educational Resources Information Center

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

2014-01-01

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

Effects of Student Population Density on Academic Achievement in Georgia Elementary Schools.

ERIC Educational Resources Information Center

Swift, Diane O'Rourke

The purpose of this study was to determine the relationship between school density and achievement test scores. The study utilized a bipolar sample in order to include schools whose achievement scores were at the top and bottom of the population spectrum when considering Iowa Tests of Basic Skills (ITBS) scores. Based on comparing test scores and…

A model-based 'varimax' sampling strategy for a heterogeneous population.

PubMed

Akram, Nuzhat A; Farooqi, Shakeel R

2014-01-01

Sampling strategies are planned to enhance the homogeneity of a sample, hence to minimize confounding errors. A sampling strategy was developed to minimize the variation within population groups. Karachi, the largest urban agglomeration in Pakistan, was used as a model population. Blood groups ABO and Rh factor were determined for 3000 unrelated individuals selected through simple random sampling. Among them five population groups, namely Balochi, Muhajir, Pathan, Punjabi and Sindhi, based on paternal ethnicity were identified. An index was designed to measure the proportion of admixture at parental and grandparental levels. Population models based on index score were proposed. For validation, 175 individuals selected through stratified random sampling were genotyped for the three STR loci CSF1PO, TPOX and TH01. ANOVA showed significant differences across the population groups for blood groups and STR loci distribution. Gene diversity was higher across the sub-population model than in the agglomerated population. At parental level gene diversities are significantly higher across No admixture models than Admixture models. At grandparental level the difference was not significant. A sub-population model with no admixture at parental level was justified for sampling the heterogeneous population of Karachi.

The Genetic-Environmental Etiology of Parents' Perceptions and Self-Assessed Behaviours toward Their 5-Month-Old Infants in a Large Twin and Singleton Sample

ERIC Educational Resources Information Center

Boivin, Michel; Perusse, Daniel; Dionne, Ginette; Saysset, Valerie; Zoccolillo, Mark; Tarabulsy, George M.; Tremblay, Nathalie; Tremblay, Richard E.

2005-01-01

Background: Given the importance of parenting for the child's early socio-emotional development, parenting perceptions and behaviours, and their correlates, should be assessed as early as possible in the child's life. The goals of the present study were 1) to confirm, in two parallel population-based samples, including a large sample of twins, the…

Community-Based Validation of the Social Phobia Screener (SOPHS).

PubMed

Batterham, Philip J; Mackinnon, Andrew J; Christensen, Helen

2017-10-01

There is a need for brief, accurate screening scales for social anxiety disorder to enable better identification of the disorder in research and clinical settings. A five-item social anxiety screener, the Social Phobia Screener (SOPHS), was developed to address this need. The screener was validated in two samples: (a) 12,292 Australian young adults screened for a clinical trial, including 1,687 participants who completed a phone-based clinical interview and (b) 4,214 population-based Australian adults recruited online. The SOPHS (78% sensitivity, 72% specificity) was found to have comparable screening performance to the Social Phobia Inventory (77% sensitivity, 71% specificity) and Mini-Social Phobia Inventory (74% sensitivity, 73% specificity) relative to clinical criteria in the trial sample. In the population-based sample, the SOPHS was also accurate (95% sensitivity, 73% specificity) in identifying Diagnostic and Statistical Manual of Mental Disorders-Fifth edition social anxiety disorder. The SOPHS is a valid and reliable screener for social anxiety that is freely available for use in research and clinical settings.

Systematic review of proposed definitions of nocturnal polyuria and population-based evidence of their diagnostic accuracy.

PubMed

Olesen, Tine Kold; Denys, Marie-Astrid; Vande Walle, Johan; Everaert, Karel

2018-02-06

Background Evidence of diagnostic accuracy for proposed definitions of nocturnal polyuria is currently unclear. Purpose Systematic review to determine population-based evidence of the diagnostic accuracy of proposed definitions of nocturnal polyuria based on data from frequency-volume charts. Methods Seventeen pre-specified search terms identified 351 unique investigations published from 1990 to 2016 in BIOSIS, Embase, Embase Alerts, International Pharmaceutical Abstract, Medline, and Cochrane. Thirteen original communications were included in this review based on pre-specified exclusion criteria. Data were extracted from each paper regarding subject age, sex, ethnicity, health status, sample size, data collection methods, and diagnostic discrimination of proposed definitions including sensitivity, specificity, positive and negative predictive value. Results The sample size of study cohorts, participant age, sex, ethnicity, and health status varied considerably in 13 studies reporting on the diagnostic performance of seven different definitions of nocturnal polyuria using frequency-volume chart data from 4968 participants. Most study cohorts were small, mono-ethnic, including only Caucasian males aged 50 or higher with primary or secondary polyuria that were compared to a control group of healthy men without nocturia in prospective or retrospective settings. Proposed definitions had poor discriminatory accuracy in evaluations based on data from subjects independent from the original study cohorts with findings being similar regarding the most widely evaluated definition endorsed by ICS. Conclusions Diagnostic performance characteristics for proposed definitions of nocturnal polyuria show poor to modest discrimination and are not based on sufficient level of evidence from representative, multi-ethnic population-based data from both females and males of all adult ages.

Smoking reduces fecundity: a European multicenter study on infertility and subfecundity. The European Study Group on Infertility and Subfecundity.

PubMed

Bolumar, F; Olsen, J; Boldsen, J

1996-03-15

Several studies published within the past 10 years indicate that smoking reduces fecundity, but not all studies have found this effect, and smoking cessation is not used routinely in infertility treatment in Europe. The present study was designed to examine male and female smoking at the start of a couple's waiting time to a planned pregnancy. Two types of samples were used: population-based samples of women aged 25-44 years who were randomly selected in different countries from census registers and electoral rolls, in which the unit of analysis was the couple; and pregnancy-based samples of pregnant women (at least 20 weeks' pregnant) who were consecutively recruited during prenatal care visits, in which the unit of analysis was a pregnancy. More than 4,000 couples were included in each sample, and 10 different regions in Europe took part in data collection. The data were collected between August 1991 and February 1993 by personal interview in all population-based samples and in all but three regions of the pregnancy sample, where self-administered questionnaires were used. The results based on the population sample showed a remarkably coherent association between female smoking and subfecundity in each individual country and in all countries together, both with the first pregnancy (odds ratio (OR) = 1.7, 95% confidence interval (CI) 1.3-2.1, at the upper level of exposure) and during the most recent waiting time to pregnancy (OR = 1.6, 95% CI 1.3-2.1). Results based on the pregnancy sample were similar (OR = 1.7, 95% CI 1.3-2.3). No significant association was found with male smoking (in the population sample, OR = 0.9, 95% CI 0.7-1.1 (first pregnancy) and OR = 1.0, 95% CI 0.9-1.3 (most recent waiting time); in the pregnancy sample, OR = 0.9, 95% CI 0.7-1.1). The fecundity distribution among smokers appeared to be shifted toward longer waiting times without a change in the shape of the distribution. Women who have difficulty conceiving should try to stop smoking or to reduce their smoking to less than 10 cigarettes per day.

Relationship between blood manganese and blood pressure in the Korean general population according to KNHANES 2008

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

Lee, Byung-Kook; Kim, Yangho, E-mail: yanghokm@nuri.net

Introduction: We present data on the association of manganese (Mn) level with hypertension in a representative sample of the adult Korean population who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) 2008. Methods: This study was based on the data obtained by KNHANES 2008, which was conducted for three years (2007-2009) using a rolling sampling design involving a complex, stratified, multistage, probability-cluster survey of a representative sample of the noninstitutionalized civilian population of South Korea. Results: Multiple regression analysis after controlling for covariates, including gender, age, regional area, education level, smoking, drinking status, hemoglobin, and serum creatinine,more » showed that the beta coefficients of log blood Mn were 3.514, 1.878, and 2.517 for diastolic blood pressure, and 3.593, 2.449, and 2.440 for systolic blood pressure in female, male, and all participants, respectively. Multiple regression analysis including three other blood metals, lead, mercury, and cadmium, revealed no significant effects of the three metals on blood pressure and showed no effect on the association between blood Mn and blood pressure. In addition, doubling the blood Mn increased the risk of hypertension 1.828, 1.573, and 1.567 fold in women, men, and all participants, respectively, after adjustment for covariates. The addition of blood lead, mercury, and cadmium as covariates did not affect the association between blood Mn and the prevalence of hypertension. Conclusion: Blood Mn level was associated with an increased risk of hypertension in a representative sample of the Korean adult population. - Highlights: {yields} We showed the association of manganese with hypertension in Korean population. {yields} This study was based on the data obtained by KNHANES 2008. {yields} Blood manganese level was associated with an increased risk of hypertension.« less

Sequence-Based Genotyping for Marker Discovery and Co-Dominant Scoring in Germplasm and Populations

PubMed Central

Truong, Hoa T.; Ramos, A. Marcos; Yalcin, Feyruz; de Ruiter, Marjo; van der Poel, Hein J. A.; Huvenaars, Koen H. J.; Hogers, René C. J.; van Enckevort, Leonora. J. G.; Janssen, Antoine; van Orsouw, Nathalie J.; van Eijk, Michiel J. T.

2012-01-01

Conventional marker-based genotyping platforms are widely available, but not without their limitations. In this context, we developed Sequence-Based Genotyping (SBG), a technology for simultaneous marker discovery and co-dominant scoring, using next-generation sequencing. SBG offers users several advantages including a generic sample preparation method, a highly robust genome complexity reduction strategy to facilitate de novo marker discovery across entire genomes, and a uniform bioinformatics workflow strategy to achieve genotyping goals tailored to individual species, regardless of the availability of a reference sequence. The most distinguishing features of this technology are the ability to genotype any population structure, regardless whether parental data is included, and the ability to co-dominantly score SNP markers segregating in populations. To demonstrate the capabilities of SBG, we performed marker discovery and genotyping in Arabidopsis thaliana and lettuce, two plant species of diverse genetic complexity and backgrounds. Initially we obtained 1,409 SNPs for arabidopsis, and 5,583 SNPs for lettuce. Further filtering of the SNP dataset produced over 1,000 high quality SNP markers for each species. We obtained a genotyping rate of 201.2 genotypes/SNP and 58.3 genotypes/SNP for arabidopsis (n = 222 samples) and lettuce (n = 87 samples), respectively. Linkage mapping using these SNPs resulted in stable map configurations. We have therefore shown that the SBG approach presented provides users with the utmost flexibility in garnering high quality markers that can be directly used for genotyping and downstream applications. Until advances and costs will allow for routine whole-genome sequencing of populations, we expect that sequence-based genotyping technologies such as SBG will be essential for genotyping of model and non-model genomes alike. PMID:22662172

Hepameta-- prevalence of hepatitis B/C and metabolic syndrome in population living in separated and segregated Roma settlements: a methodology for a cross-sectional population-based study using community-based approach.

PubMed

Gecková, Andrea Madarasová; Jarcuska, Peter; Mareková, Mária; Pella, Daniel; Siegfried, Leonard; Jarcuska, Pavol; Halánová, Monika

2014-03-01

Roma represent one of the largest and oldest minorities in Europe. Health of many of them, particularly those living in settlements, is heavily compromised by poor dwelling, low educational level, unemployment, and poverty rooted in generational poverty, segregation and discrimination. The cross-sectional population-based study using community based approach aimed to map the prevalence of viral hepatitis B/C and metabolic syndrome in the population living in separated and segregated Roma settlements and to compare it with the occurrence of the same health indicators in the majority population, considering selected risk and protective factors of these health indicators. The sample consisted of 452 Roma (mean age = 34.7; 35.2% men) and 403 non-Roma (mean age = 33.5; 45.9% men) respondents. Data were collected in 2011 via questionnaire, anthropometric measures and analysed blood and urine samples. A methodology used in the study as well as in the following scientific papers is described in the Methods section (i.e. study design, procedures, samples, methods including questionnaire, anthropometric measurements, physical measurements, blood and urine measurements). There are regions of declining prosperity due to high unemployment, long-term problems with poverty and depleted resources. Populations living in these areas, i.e. in Central and Eastern Europe in Roma settlements, are at risk of poverty, social exclusion and other factors affecting health. Therefore, we should look for successful long-term strategies and tools (e.g. Roma mediators, terrain work) in order to improve the future prospects of these minorities.

Coalescent genealogy samplers: windows into population history

PubMed Central

Kuhner, Mary K.

2016-01-01

Coalescent genealogy samplers attempt to estimate past qualities of a population, such as its size, growth rate, patterns of gene flow or time of divergence from another population, based on samples of molecular data. Genealogy samplers are increasingly popular because of their potential to disentangle complex population histories. In the last decade they have been widely applied to systems ranging from humans to viruses. Findings include detection of unexpected reproductive inequality in fish, new estimates of historical whale abundance, exoneration of humans for the prehistoric decline of bison and inference of a selective sweep on the human Y chromosome. This review summarizes available genealogy-sampler software, including data requirements and limitations on the use of each program. PMID:19101058

Coalescent genealogy samplers: windows into population history.

PubMed

Kuhner, Mary K

2009-02-01

Coalescent genealogy samplers attempt to estimate past qualities of a population, such as its size, growth rate, patterns of gene flow or time of divergence from another population, based on samples of molecular data. Genealogy samplers are increasingly popular because of their potential to disentangle complex population histories. In the last decade they have been widely applied to systems ranging from humans to viruses. Findings include detection of unexpected reproductive inequality in fish, new estimates of historical whale abundance, exoneration of humans for the prehistoric decline of bison and inference of a selective sweep on the human Y chromosome. This review summarizes available genealogy-sampler software, including data requirements and limitations on the use of each program.

A simple risk score for identifying individuals with impaired fasting glucose in the Southern Chinese population.

PubMed

Wang, Hui; Liu, Tao; Qiu, Quan; Ding, Peng; He, Yan-Hui; Chen, Wei-Qing

2015-01-23

This study aimed to develop and validate a simple risk score for detecting individuals with impaired fasting glucose (IFG) among the Southern Chinese population. A sample of participants aged ≥20 years and without known diabetes from the 2006-2007 Guangzhou diabetes cross-sectional survey was used to develop separate risk scores for men and women. The participants completed a self-administered structured questionnaire and underwent simple clinical measurements. The risk scores were developed by multiple logistic regression analysis. External validation was performed based on three other studies: the 2007 Zhuhai rural population-based study, the 2008-2010 Guangzhou diabetes cross-sectional study and the 2007 Tibet population-based study. Performance of the scores was measured with the Hosmer-Lemeshow goodness-of-fit test and ROC c-statistic. Age, waist circumference, body mass index and family history of diabetes were included in the risk score for both men and women, with the additional factor of hypertension for men. The ROC c-statistic was 0.70 for both men and women in the derivation samples. Risk scores of ≥28 for men and ≥18 for women showed respective sensitivity, specificity, positive predictive value and negative predictive value of 56.6%, 71.7%, 13.0% and 96.0% for men and 68.7%, 60.2%, 11% and 96.0% for women in the derivation population. The scores performed comparably with the Zhuhai rural sample and the 2008-2010 Guangzhou urban samples but poorly in the Tibet sample. The performance of pre-existing USA, Shanghai, and Chengdu risk scores was poorer in our population than in their original study populations. The results suggest that the developed simple IFG risk scores can be generalized in Guangzhou city and nearby rural regions and may help primary health care workers to identify individuals with IFG in their practice.

A Simple Risk Score for Identifying Individuals with Impaired Fasting Glucose in the Southern Chinese Population

PubMed Central

Wang, Hui; Liu, Tao; Qiu, Quan; Ding, Peng; He, Yan-Hui; Chen, Wei-Qing

2015-01-01

This study aimed to develop and validate a simple risk score for detecting individuals with impaired fasting glucose (IFG) among the Southern Chinese population. A sample of participants aged ≥20 years and without known diabetes from the 2006–2007 Guangzhou diabetes cross-sectional survey was used to develop separate risk scores for men and women. The participants completed a self-administered structured questionnaire and underwent simple clinical measurements. The risk scores were developed by multiple logistic regression analysis. External validation was performed based on three other studies: the 2007 Zhuhai rural population-based study, the 2008–2010 Guangzhou diabetes cross-sectional study and the 2007 Tibet population-based study. Performance of the scores was measured with the Hosmer-Lemeshow goodness-of-fit test and ROC c-statistic. Age, waist circumference, body mass index and family history of diabetes were included in the risk score for both men and women, with the additional factor of hypertension for men. The ROC c-statistic was 0.70 for both men and women in the derivation samples. Risk scores of ≥28 for men and ≥18 for women showed respective sensitivity, specificity, positive predictive value and negative predictive value of 56.6%, 71.7%, 13.0% and 96.0% for men and 68.7%, 60.2%, 11% and 96.0% for women in the derivation population. The scores performed comparably with the Zhuhai rural sample and the 2008–2010 Guangzhou urban samples but poorly in the Tibet sample. The performance of pre-existing USA, Shanghai, and Chengdu risk scores was poorer in our population than in their original study populations. The results suggest that the developed simple IFG risk scores can be generalized in Guangzhou city and nearby rural regions and may help primary health care workers to identify individuals with IFG in their practice. PMID:25625405

Correlates of low back pain in a general population sample: a multidisciplinary perspective.

PubMed

Roncarati, A; McMullen, W

1988-06-01

This study identifies correlates of low back pain in a general population sample and defines a profile of subjects with low back pain. A multidisciplinary approach was employed that required surveying and physically assessing 674 subjects on 105 variables in biographical, anatomical, strength and flexibility measurement categories. No attempt was made to select subjects from specific occupational, age, athletic, psychological and anatomical groups or subjects with specific biographical features, which may have resulted in a sample that was atypical of the general population. The results of this study based on a causal comparative ex post facto research design corroborated selected findings of previous research conducted on nongeneral population samples. These findings include relationships between low back pain and age, body type, sex, stress, smoking, selected types of physical activity, occupation and previous injuries to the neck, shoulders, back and upper legs, as well as previous episodes of low back pain. Additional correlates of low back pain that were identified and have little or controversial review in the back literature include: delayed low back pain syndrome caused by abrupt changes in running frequency, Q angle, pes cavus, leg length (right and left), trunk length, genu recurvatum and multiplane strength and flexibility limitations in the hip joints.

Association between obesity and depressive disorder in adolescents at high risk for depression.

PubMed

Hammerton, G; Thapar, A; Thapar, A K

2014-04-01

To examine the relationship between Body Mass Index (BMI) and depressive disorder in adolescents at high risk for depression. Prospective longitudinal 3-wave study of offspring of parents with recurrent depression. Replication in population-based cohort study. Three hundred and thirty-seven families where offspring were aged 9-17 years at baseline and 10-19 years at the final data point. Replication sample of adolescents from population-based cohort study aged 11-13 years at first assessment and 14-17 years at follow-up. High risk sample used BMI, skin-fold thickness, Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV)-defined major depressive disorder and depression symptoms using the Child and Adolescent Psychiatric Assessment (CAPA). Replication sample used BMI, DSM-IV depressive disorder and depression symptoms using the Development and Well-Being Assessment (DAWBA). Two hundred and eighty-nine adolescents were included in the primary analyses. The mean BMI for each age group in this sample were significantly higher than population norms. There was no significant longitudinal association between categories of weight (or BMI) and new onset depressive disorder or depression symptoms. Similar results were found for skin-fold thickness. The association was also tested in a replication population-based sample and found to be non-significant in the subsample of offspring with mothers who had experienced recurrent depression in the past. BMI at age 12 years was, however, a significant predictor of depression symptoms but not of depressive disorder at age 15 years for the total unselected population. BMI does not significantly predict the development of depression in the offspring of parents with recurrent depression.

Statistical power calculations for mixed pharmacokinetic study designs using a population approach.

PubMed

Kloprogge, Frank; Simpson, Julie A; Day, Nicholas P J; White, Nicholas J; Tarning, Joel

2014-09-01

Simultaneous modelling of dense and sparse pharmacokinetic data is possible with a population approach. To determine the number of individuals required to detect the effect of a covariate, simulation-based power calculation methodologies can be employed. The Monte Carlo Mapped Power method (a simulation-based power calculation methodology using the likelihood ratio test) was extended in the current study to perform sample size calculations for mixed pharmacokinetic studies (i.e. both sparse and dense data collection). A workflow guiding an easy and straightforward pharmacokinetic study design, considering also the cost-effectiveness of alternative study designs, was used in this analysis. Initially, data were simulated for a hypothetical drug and then for the anti-malarial drug, dihydroartemisinin. Two datasets (sampling design A: dense; sampling design B: sparse) were simulated using a pharmacokinetic model that included a binary covariate effect and subsequently re-estimated using (1) the same model and (2) a model not including the covariate effect in NONMEM 7.2. Power calculations were performed for varying numbers of patients with sampling designs A and B. Study designs with statistical power >80% were selected and further evaluated for cost-effectiveness. The simulation studies of the hypothetical drug and the anti-malarial drug dihydroartemisinin demonstrated that the simulation-based power calculation methodology, based on the Monte Carlo Mapped Power method, can be utilised to evaluate and determine the sample size of mixed (part sparsely and part densely sampled) study designs. The developed method can contribute to the design of robust and efficient pharmacokinetic studies.

Establishment of a cervical cancer bio-bank for the Chinese population: from project-based sample collection to routine management.

PubMed

Yang, Ru; Li, Xiong; Zhou, Hang; Jia, Yao; Zhou, Jin; Huang, Kecheng; Tang, Fangxu; Hu, Ting; Shen, Jian; Chen, Zhilan; Wang, Shaoshuai; Sun, Haiying; Guo, Lili; Wang, Lin; Wang, Hui; Ma, Ding; Li, Shuang

2015-08-01

There is an increasing need for the establishment of a cervical cancer bio-bank that will facilitate both clinical and basic research. The cervical cancer bio-bank was first established in January 1999 and included two stages. First, a GWAS-based sample collection was conducted with special emphasis on the diagnosis and the retrieval of the corresponding bio-specimens, especially blood samples. Second, clinical data and their corresponding bio-specimens were routinely collected and handled. Notably, these bio-specimens also included samples from Wufeng Tujia Autonomous County, which has the highest incidence of cervical cancer in China. The specimens were collected from patients with cervical cancer and those with cervical intraepithelial neoplasia, while the control samples were collected from normal individuals. With special emphasis on clinical data and blood samples for the GWAS analysis, the collection of other bio-specimens was slow, and the pairing of specimens and clinical data was poor during the first stage. However, in the second stage, the pairing of the clinical data and its corresponding bio-specimens improved. At present, the samples procured and preserved in the bio-bank cover most regions of China and different ethnic groups for both the normal controls and cervical cancer patients of different pathological categories. This bio-bank of cervical cancer specimens from the Chinese population will greatly promote the studies of cervical cancer in China.

Uncertainty, learning, and the optimal management of wildlife

USGS Publications Warehouse

Williams, B.K.

2001-01-01

Wildlife management is limited by uncontrolled and often unrecognized environmental variation, by limited capabilities to observe and control animal populations, and by a lack of understanding about the biological processes driving population dynamics. In this paper I describe a comprehensive framework for management that includes multiple models and likelihood values to account for structural uncertainty, along with stochastic factors to account for environmental variation, random sampling, and partial controllability. Adaptive optimization is developed in terms of the optimal control of incompletely understood populations, with the expected value of perfect information measuring the potential for improving control through learning. The framework for optimal adaptive control is generalized by including partial observability and non-adaptive, sample-based updating of model likelihoods. Passive adaptive management is derived as a special case of constrained adaptive optimization, representing a potentially efficient suboptimal alternative that nonetheless accounts for structural uncertainty.

Prevalence of Latent Mycobacterium Tuberculosis Infection (LTBI) in Saudi Arabia; Population based survey.

PubMed

Balkhy, Hanan H; El Beltagy, Kamel; El-Saed, Aiman; Aljasir, Badr; Althaqafi, Abdulhakeem; Alothman, Adel F; Alshalaan, Mohammad; Al-Jahdali, Hamdan

2017-07-01

The annual risk of tuberculosis infection (ARTI) data in Saudi Arabia has not been updated since 1993. To estimate the prevalence of latent TB infection (LTBI) and ARTI in a population-based sample in Saudi Arabia using Tuberculin skin test (TST) and QuantiFERON TB Gold in tube (QFT-GIT) test. A population-based cross sectional study was conducted between July 2010 and March 2013. Participants were randomly selected from the population served by the primary healthcare centers of the Ministry of National Guard Health Affairs in Riyadh, Jeddah, Alhassa and Dammam, Saudi Arabia. A total of 1369 participants were included. The overall prevalence of LTBI was similar using TST and QFT-GIT (9.3% and 9.1% respectively, p=0.872) but stratified prevalence rates were variable in all sociodemographic groups except marital status. Additionally, the prevalence rates of LTBI using either test alone showed significant differences by several sociodemographic and behavioral characteristics. The overall ARTI was 0.36% using TST and 0.35% using QFT-GIT. We are reporting much lower estimates for the prevalence of LTBI and the ARTI in a population-based sample in Saudi Arabia relative to the data that have been used for more than two decades. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Long-Term Physical and Mental Health Consequences of Childhood Physical Abuse: Results from a Large Population-Based Sample of Men and Women

ERIC Educational Resources Information Center

Springer, Kristen W.; Sheridan, Jennifer; Kuo, Daphne; Carnes, Molly

2007-01-01

Objective: Child maltreatment has been linked to negative adult health outcomes; however, much past research includes only clinical samples of women, focuses exclusively on sexual abuse and/or fails to control for family background and childhood characteristics, both potential confounders. Further research is needed to obtain accurate,…

Evaluating the performance of the Lee-Carter method and its variants in modelling and forecasting Malaysian mortality

NASA Astrophysics Data System (ADS)

Zakiyatussariroh, W. H. Wan; Said, Z. Mohammad; Norazan, M. R.

2014-12-01

This study investigated the performance of the Lee-Carter (LC) method and it variants in modeling and forecasting Malaysia mortality. These include the original LC, the Lee-Miller (LM) variant and the Booth-Maindonald-Smith (BMS) variant. These methods were evaluated using Malaysia's mortality data which was measured based on age specific death rates (ASDR) for 1971 to 2009 for overall population while those for 1980-2009 were used in separate models for male and female population. The performance of the variants has been examined in term of the goodness of fit of the models and forecasting accuracy. Comparison was made based on several criteria namely, mean square error (MSE), root mean square error (RMSE), mean absolute deviation (MAD) and mean absolute percentage error (MAPE). The results indicate that BMS method was outperformed in in-sample fitting for overall population and when the models were fitted separately for male and female population. However, in the case of out-sample forecast accuracy, BMS method only best when the data were fitted to overall population. When the data were fitted separately for male and female, LCnone performed better for male population and LM method is good for female population.

Approaches to Recruiting ‘Hard-To-Reach’ Populations into Re­search: A Review of the Literature

PubMed Central

Shaghaghi, Abdolreza; Bhopal, Raj S; Sheikh, Aziz

2011-01-01

Background: ‘Hard-to-reach’ is a term used to describe those sub-groups of the population that may be difficult to reach or involve in research or public health programmes. Application of a single term to call these sub-sections of populations implies a homogeneity within distinct groups, which does not necessarily exist. Different sampling techniques were introduced so far to recruit hard-to-reach populations. In this article, we have reviewed a range of ap­proaches that have been used to widen participation in studies. Methods: We performed a Pubmed and Google search for relevant English language articles using the keywords and phrases: (hard-to-reach AND population* OR sampl*), (hidden AND population* OR sample*) and (“hard to reach” AND population* OR sample*) and a consul­tation of the retrieved articles’ bibliographies to extract empirical evidence from publications that discussed or examined the use of sampling techniques to recruit hidden or hard-to-reach populations in health studies. Results: Reviewing the literature has identified a range of techniques to recruit hard-to-reach populations, including snowball sampling, respondent-driven sampling (RDS), indigenous field worker sampling (IFWS), facility-based sampling (FBS), targeted sampling (TS), time-location (space) sampling (TLS), conventional cluster sampling (CCS) and capture re-capture sampling (CR). Conclusion: The degree of compliance with a study by a certain ‘hard-to-reach’ group de­pends on the characteristics of that group, recruitment technique used and the subject of inter­est. Irrespective of potential advantages or limitations of the recruitment techniques reviewed, their successful use depends mainly upon our knowledge about specific characteristics of the target populations. Thus in line with attempts to expand the current boundaries of our know­ledge about recruitment techniques in health studies and their applications in varying situa­tions, we should also focus on possibly all contributing factors which may have an impact on participation rate within a defined population group. PMID:24688904

Chlamyweb Study I: rationale, design and acceptability of an internet-based chlamydia testing intervention.

PubMed

Lydié, Nathalie; de Barbeyrac, Bertille; Bluzat, Lucile; Le Roy, Chloé; Kersaudy-Rahib, Delphine

2017-05-01

In recent years, the internet has widely facilitated Chlamydia trachomatis home-sampling. In France (2012), the Chlamyweb Study evaluated an intervention (Chlamyweb) involving home-based self-sampling via the internet. One element of the study consisted of a randomised controlled trial (RCT), which is reported in detail elsewhere. The focus of this paper, however, is on describing the Chlamyweb Intervention and reporting on the non-RCT element of the evaluation of that intervention by the Chlamyweb Study. This involves (1) describing the design and roll-out of the Chlamyweb Intervention, (2) comparing the socio-behavioural profiles of the participants in the intervention with a nationally representative general population sample and (3) examining the factors that influence the acceptance and return of a self-sampling kit supplied to participants in the course of the intervention. Self-sampling kits were offered to sexually active people aged 18-24 years living on the mainland French. Participants' characteristics were compared with the general population to describe recruited and participant populations. Multivariate analyses by conditional logistic regression were performed to determine factors that were predictors of kit acceptation and use. 7215 people aged 18-24 years were included. Compared with the general population, Chlamyweb reached larger proportions of women, younger people and people with several partners in the previous year. 3372 (46.7%) agreed to receive a self-sampling kit and 2084 (61.8%) returned it, with more women doing so than men. The participation rate was associated with age, place of birth, occupational status, number of partners and condom use, differently for men and women. The offer of easy-to-use, self-sampling kits free of charge appeared to be a logistically feasible strategy for testing in France and reached a large and diverse population including individuals who have limited access to the traditional healthcare system. AFFSAPS n° IDRCB 0211-A01000-41; pre-results. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Building Better Planet Populations for EXOSIMS

NASA Astrophysics Data System (ADS)

Garrett, Daniel; Savransky, Dmitry

2018-01-01

The Exoplanet Open-Source Imaging Mission Simulator (EXOSIMS) software package simulates ensembles of space-based direct imaging surveys to provide a variety of science and engineering yield distributions for proposed mission designs. These mission simulations rely heavily on assumed distributions of planetary population parameters including semi-major axis, planetary radius, eccentricity, albedo, and orbital orientation to provide heuristics for target selection and to simulate planetary systems for detection and characterization. The distributions are encoded in PlanetPopulation modules within EXOSIMS which are selected by the user in the input JSON script when a simulation is run. The earliest written PlanetPopulation modules available in EXOSIMS are based on planet population models where the planetary parameters are considered to be independent from one another. While independent parameters allow for quick computation of heuristics and sampling for simulated planetary systems, results from planet-finding surveys have shown that many parameters (e.g., semi-major axis/orbital period and planetary radius) are not independent. We present new PlanetPopulation modules for EXOSIMS which are built on models based on planet-finding survey results where semi-major axis and planetary radius are not independent and provide methods for sampling their joint distribution. These new modules enhance the ability of EXOSIMS to simulate realistic planetary systems and give more realistic science yield distributions.

Invited review: study design considerations for clinical research in veterinary radiology and radiation oncology.

PubMed

Scrivani, Peter V; Erb, Hollis N

2013-01-01

High quality clinical research is essential for advancing knowledge in the areas of veterinary radiology and radiation oncology. Types of clinical research studies may include experimental studies, method-comparison studies, and patient-based studies. Experimental studies explore issues relative to pathophysiology, patient safety, and treatment efficacy. Method-comparison studies evaluate agreement between techniques or between observers. Patient-based studies investigate naturally acquired disease and focus on questions asked in clinical practice that relate to individuals or populations (e.g., risk, accuracy, or prognosis). Careful preplanning and study design are essential in order to achieve valid results. A key point to planning studies is ensuring that the design is tailored to the study objectives. Good design includes a comprehensive literature review, asking suitable questions, selecting the proper sample population, collecting the appropriate data, performing the correct statistical analyses, and drawing conclusions supported by the available evidence. Most study designs are classified by whether they are experimental or observational, longitudinal or cross-sectional, and prospective or retrospective. Additional features (e.g., controlled, randomized, or blinded) may be described that address bias. Two related challenging aspects of study design are defining an important research question and selecting an appropriate sample population. The sample population should represent the target population as much as possible. Furthermore, when comparing groups, it is important that the groups are as alike to each other as possible except for the variables of interest. Medical images are well suited for clinical research because imaging signs are categorical or numerical variables that might be predictors or outcomes of diseases or treatments. © 2013 Veterinary Radiology & Ultrasound.

A population-based study of associations between current posttraumatic stress symptoms and current fatigue.

PubMed

Lerdal, Anners; Lee, Kathryn A; Rokne, Berit; Knudsen, Øistein; Wahl, Astrid K; Dahl, Alv A

2010-10-01

This study explores current experience with posttraumatic stress disorder (PTSD) symptoms and other variables (sociodemographic, mental distress, somatic morbidity, self-rated health, and quality of life [QoL]) in relation to fatigue. A representative sample of the Norwegian population (N = 3,944) was invited to participate in a mailed survey, and 1,857 (47%) returned valid responses on the questionnaire that included the Fatigue Severity Scale and the Posttraumatic Symptom Scale-10. Posttraumatic stress disorder symptoms showed a strong association with fatigue in univariate (β = .41) and multivariate analyses (β = .33). Associations between psychosocial health variables, QoL, and fatigue were confirmed. However, PTSD symptoms showed the strongest association with fatigue in the analyses. Findings need to be replicated in other population samples and in clinical samples with PTSD and fatigue.

A methodological approach to improve the sexual health of vulnerable female populations: incentivized peer-recruitment and field-based STD testing.

PubMed

Roth, Alexis M; Rosenberger, Joshua G; Reece, Michael; Van Der Pol, Barbara

2012-02-01

Transactional sex has been associated with increased risk of adverse health outcomes, including sexually transmitted infections (STIs). Participants included female sex workers and men they recruited utilizing incentivized snowball sampling. Participants provided specimens for STI diagnostic testing and completed a semi-structured interview. Forty-four participants aged 19-65 were interviewed. Participants found self-sampling to be acceptable and overwhelmingly endorsed sampling outside of a clinic (90%) for reasons such as convenience, privacy, and lack of stigma. A substantial minority (38%) tested positive for at least one STI. Novel strategies may encourage sexual health care and prevent STIs among sex workers. High infection and screening acceptance rates across the sample suggests that individuals engaged in transactional sex would benefit from, and would be responsive to, community-based self-sampling for STI screening.

Analysis of five-year trends in self-reported language preference and issues of item non-response among Hispanic persons in a large cross-sectional health survey: implications for the measurement of an ethnic minority population

PubMed Central

2010-01-01

Background Significant differences in health outcomes have been documented among Hispanic persons, the fastest-growing demographic segment of the United States. The objective of this study was to examine trends in population growth and the collection of health data among Hispanic persons, including issues of language preference and survey completion using a national health survey to highlight issues of measurement of an increasingly important demographic segment of the United States. Design Data from the 2003-2007 United States Census and the Behavioral Risk Factor Surveillance System were used to compare trends in population growth and survey sample size as well as differences in survey response based on language preference among a Hispanic population. Percentages of item non-response on selected survey questions were compared for Hispanic respondents choosing to complete the survey in Spanish and those choosing to complete the survey in English. The mean number of attempts to complete the survey was also compared based on language preference among Hispanic respondents. Results The sample size of Hispanic persons in the Behavioral Risk Factor Surveillance System saw little growth compared to the actual growth of the Hispanic population in the United States. Significant differences in survey item non-response for nine of 15 survey questions were seen based on language preference. Hispanic respondents choosing to complete the survey in Spanish had a significantly fewer number of call attempts for survey completion compared to their Hispanic counterparts choosing to communicate in English. Conclusions Including additional measures of acculturation and increasing the sample size of Hispanic persons in a national health survey such as the Behavioral Risk Factor Surveillance System may result in more precise findings that could be used to better target prevention and health care needs for an ethnic minority population. PMID:20412575

Comparison of Address-based Sampling and Random-digit Dialing Methods for Recruiting Young Men as Controls in a Case-Control Study of Testicular Cancer Susceptibility

PubMed Central

Clagett, Bartholt; Nathanson, Katherine L.; Ciosek, Stephanie L.; McDermoth, Monique; Vaughn, David J.; Mitra, Nandita; Weiss, Andrew; Martonik, Rachel; Kanetsky, Peter A.

2013-01-01

Random-digit dialing (RDD) using landline telephone numbers is the historical gold standard for control recruitment in population-based epidemiologic research. However, increasing cell-phone usage and diminishing response rates suggest that the effectiveness of RDD in recruiting a random sample of the general population, particularly for younger target populations, is decreasing. In this study, we compared landline RDD with alternative methods of control recruitment, including RDD using cell-phone numbers and address-based sampling (ABS), to recruit primarily white men aged 18–55 years into a study of testicular cancer susceptibility conducted in the Philadelphia, Pennsylvania, metropolitan area between 2009 and 2012. With few exceptions, eligible and enrolled controls recruited by means of RDD and ABS were similar with regard to characteristics for which data were collected on the screening survey. While we find ABS to be a comparably effective method of recruiting young males compared with landline RDD, we acknowledge the potential impact that selection bias may have had on our results because of poor overall response rates, which ranged from 11.4% for landline RDD to 1.7% for ABS. PMID:24008901

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.

Irish study of high-density Schizophrenia families: Field methods and power to detect linkage

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

Kendler, K.S.; Straub, R.E.; MacLean, C.J.

Large samples of multiplex pedigrees will probably be needed to detect susceptibility loci for schizophrenia by linkage analysis. Standardized ascertainment of such pedigrees from culturally and ethnically homogeneous populations may improve the probability of detection and replication of linkage. The Irish Study of High-Density Schizophrenia Families (ISHDSF) was formed from standardized ascertainment of multiplex schizophrenia families in 39 psychiatric facilities covering over 90% of the population in Ireland and Northern Ireland. We here describe a phenotypic sample and a subset thereof, the linkage sample. Individuals were included in the phenotypic sample if adequate diagnostic information, based on personal interview and/ormore » hospital record, was available. Only individuals with available DNA were included in the linkage sample. Inclusion of a pedigree into the phenotypic sample required at least two first, second, or third degree relatives with non-affective psychosis (NAP), one of whom had schizophrenia (S) or poor-outcome schizoaffective disorder (PO-SAD). Entry into the linkage sample required DNA samples on at least two individuals with NAP, of whom at least one had S or PO-SAD. Affection was defined by narrow, intermediate, and broad criteria. 75 refs., 6 tabs.« less

[Use of blood lead data to evaluate and prevent childhood lead poisoning in Latin America].

PubMed

Romieu, Isabelle

2003-01-01

Exposure to lead is a widespread and serious threat to the health of children in Latin America. Health officials should monitor sources of exposure and health outcomes to design, implement, and evaluate prevention and control activities. To evaluate the magnitude of lead as a public health problem, three key elements must be defined: I) the potential sources of exposure, 2) the indicators to evaluate health effects and environmental exposure, and 3) the sampling methods for the population at risk. Several strategies can be used to select the study population depending on the study objectives, the time limitations, and the available resources. If the objective is to evaluate the magnitude and sources of the problem, the following sampling methods can be used: I) population-based random sampling; 2) facility-based random sampling within hospitals, daycare centers, or schools; 3) target sampling of high risk groups; 4) convenience sampling of volunteers; and 5) case reporting (which can lead to the identification of populations at risk and sources of exposures). For all sampling methods, information gathering should include the use of a questionnaire to collect general information on the participants and on potential local sources of exposure, as well as the collection of biological samples. In interpreting data, one should consider the type of sampling used and the non-response rates, as well as factors that might influence blood lead measurements, such as age and seasonal variability. Blood lead measurements should be integrated in an overall strategy to prevent lead toxicity in children. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

Diagnostic test accuracy and prevalence inferences based on joint and sequential testing with finite population sampling.

PubMed

Su, Chun-Lung; Gardner, Ian A; Johnson, Wesley O

2004-07-30

The two-test two-population model, originally formulated by Hui and Walter, for estimation of test accuracy and prevalence estimation assumes conditionally independent tests, constant accuracy across populations and binomial sampling. The binomial assumption is incorrect if all individuals in a population e.g. child-care centre, village in Africa, or a cattle herd are sampled or if the sample size is large relative to population size. In this paper, we develop statistical methods for evaluating diagnostic test accuracy and prevalence estimation based on finite sample data in the absence of a gold standard. Moreover, two tests are often applied simultaneously for the purpose of obtaining a 'joint' testing strategy that has either higher overall sensitivity or specificity than either of the two tests considered singly. Sequential versions of such strategies are often applied in order to reduce the cost of testing. We thus discuss joint (simultaneous and sequential) testing strategies and inference for them. Using the developed methods, we analyse two real and one simulated data sets, and we compare 'hypergeometric' and 'binomial-based' inferences. Our findings indicate that the posterior standard deviations for prevalence (but not sensitivity and specificity) based on finite population sampling tend to be smaller than their counterparts for infinite population sampling. Finally, we make recommendations about how small the sample size should be relative to the population size to warrant use of the binomial model for prevalence estimation. Copyright 2004 John Wiley & Sons, Ltd.

The role of mental health, personality disorders and childhood adversities in relation to life satisfaction in a sample of general population.

PubMed

Rissanen, Teemu; Viinamäki, Heimo; Lehto, Soili M; Hintikka, Jukka; Honkalampi, Kirsi; Saharinen, Tarja; Koivumaa-Honkanen, Heli

2013-04-01

Mental health disorders are one of the leading causes of the disease burden globally. The aim of this population-based study was to investigate the relationship between life satisfaction and mental health by taking into account its less studied areas, such as personality disorders and childhood adversities. The sample of this cross-sectional study was derived from a population-based Kuopio Depression Study performed in Eastern Finland. Health questionnaires were mailed in 1998, 1999, 2001 and 2005 including questions on several clinical factors. Questions on childhood home were asked in 1999. The inclusion criteria for the final study sample in 2005 were based on previously repeatedly (1998, 1999, 2001) reported life satisfaction, depression or alexithymic features (with/without). Psychiatric diagnoses of major depressive disorder and personality disorder were confirmed by structured clinical interview I and II for DSM-IV in 2005. Logistic regression analyses were performed to assess the studied relationships. In general, the broad spectrum of poor mental health indicators was associated with concurrent life dissatisfaction. After multiple adjustments, major depressive disorder (MDD), hopelessness and mental distress remained independent correlates of life dissatisfaction, while personality disorder or self-reported childhood adversities lost their significance when these other factors were included in the model. Mental health is closely interwoven with life satisfaction. Even if personality disorder and childhood adversities were significant correlates of life dissatisfaction, adverse concurrent mental symptoms and features and MDD were its strongest correlates.

Lifetime Prevalence of Suicide Attempts Among Sexual Minority Adults by Study Sampling Strategies: A Systematic Review and Meta-Analysis.

PubMed

Hottes, Travis Salway; Bogaert, Laura; Rhodes, Anne E; Brennan, David J; Gesink, Dionne

2016-05-01

Previous reviews have demonstrated a higher risk of suicide attempts for lesbian, gay, and bisexual (LGB) persons (sexual minorities), compared with heterosexual groups, but these were restricted to general population studies, thereby excluding individuals sampled through LGB community venues. Each sampling strategy, however, has particular methodological strengths and limitations. For instance, general population probability studies have defined sampling frames but are prone to information bias associated with underreporting of LGB identities. By contrast, LGB community surveys may support disclosure of sexuality but overrepresent individuals with strong LGB community attachment. To reassess the burden of suicide-related behavior among LGB adults, directly comparing estimates derived from population- versus LGB community-based samples. In 2014, we searched MEDLINE, EMBASE, PsycInfo, CINAHL, and Scopus databases for articles addressing suicide-related behavior (ideation, attempts) among sexual minorities. We selected quantitative studies of sexual minority adults conducted in nonclinical settings in the United States, Canada, Europe, Australia, and New Zealand. Random effects meta-analysis and meta-regression assessed for a difference in prevalence of suicide-related behavior by sample type, adjusted for study or sample-level variables, including context (year, country), methods (medium, response rate), and subgroup characteristics (age, gender, sexual minority construct). We examined residual heterogeneity by using τ(2). We pooled 30 cross-sectional studies, including 21,201 sexual minority adults, generating the following lifetime prevalence estimates of suicide attempts: 4% (95% confidence interval [CI] = 3%, 5%) for heterosexual respondents to population surveys, 11% (95% CI = 8%, 15%) for LGB respondents to population surveys, and 20% (95% CI = 18%, 22%) for LGB respondents to community surveys (Figure 1). The difference in LGB estimates by sample type persisted after we accounted for covariates with meta-regression. Sample type explained 33% of the between-study variability. Regardless of sample type examined, sexual minorities had a higher lifetime prevalence of suicide attempts than heterosexual persons; however, the magnitude of this disparity was contingent upon sample type. Community-based surveys of LGB people suggest that 20% of sexual minority adults have attempted suicide. Accurate estimates of sexual minority health disparities are necessary for public health monitoring and research. Most data describing these disparities are derived from 2 sample types, which yield different estimates of the lifetime prevalence of suicide attempts. Additional studies should explore the differential effects of selection and information biases on the 2 predominant sampling approaches used to understand sexual minority health.

Serum markers for type II diabetes mellitus

DOEpatents

Metz, Thomas O; Qian, Wei-Jun; Jacobs, Jon M; Polpitiya, Ashoka D; Camp, II, David G; Smith, Richard D

2014-03-18

A method for identifying persons with increased risk of developing type 2 diabetes mellitus utilizing selected biomarkers described hereafter either alone or in combination. The present invention allows for broad based, reliable, screening of large population bases and provides other advantages, including the formulation of effective strategies for characterizing, archiving, and contrasting data from multiple sample types under varying conditions.

Hard-to-reach populations of men who have sex with men and sex workers: a systematic review on sampling methods.

PubMed

Barros, Ana B; Dias, Sonia F; Martins, Maria Rosario O

2015-10-30

In public health, hard-to-reach populations are often recruited by non-probabilistic sampling methods that produce biased results. In order to overcome this, several sampling methods have been improved and developed in the last years. The aim of this systematic review was to identify all current methods used to survey most-at-risk populations of men who have sex with men and sex workers. The review also aimed to assess if there were any relations between the study populations and the sampling methods used to recruit them. Lastly, we wanted to assess if the number of publications originated in middle and low human development (MLHD) countries had been increasing in the last years. A systematic review was conducted using electronic databases and a total of 268 published studies were included in the analysis. In this review, 11 recruitment methods were identified. Semi-probabilistic methods were used most commonly to survey men who have sex with men, and the use of the Internet was the method that gathered more respondents. We found that female sex workers were more frequently recruited through non-probabilistic methods than men who have sex with men (odds = 2.2; p < 0.05; confidence interval (CI) [1.1-4.2]). In the last 6 years, the number of studies based in middle and low human development countries increased more than the number of studies based in very high and high human development countries (odds = 2.5; p < 0.05; CI [1.3-4.9]). This systematic literature review identified 11 methods used to sample men who have sex with men and female sex workers. There is an association between the type of sampling method and the population being studied. The number of studies based in middle and low human development countries has increased in the last 6 years of this study.

Genetic demographic networks: Mathematical model and applications.

PubMed

Kimmel, Marek; Wojdyła, Tomasz

2016-10-01

Recent improvement in the quality of genetic data obtained from extinct human populations and their ancestors encourages searching for answers to basic questions regarding human population history. The most common and successful are model-based approaches, in which genetic data are compared to the data obtained from the assumed demography model. Using such approach, it is possible to either validate or adjust assumed demography. Model fit to data can be obtained based on reverse-time coalescent simulations or forward-time simulations. In this paper we introduce a computational method based on mathematical equation that allows obtaining joint distributions of pairs of individuals under a specified demography model, each of them characterized by a genetic variant at a chosen locus. The two individuals are randomly sampled from either the same or two different populations. The model assumes three types of demographic events (split, merge and migration). Populations evolve according to the time-continuous Moran model with drift and Markov-process mutation. This latter process is described by the Lyapunov-type equation introduced by O'Brien and generalized in our previous works. Application of this equation constitutes an original contribution. In the result section of the paper we present sample applications of our model to both simulated and literature-based demographies. Among other we include a study of the Slavs-Balts-Finns genetic relationship, in which we model split and migrations between the Balts and Slavs. We also include another example that involves the migration rates between farmers and hunters-gatherers, based on modern and ancient DNA samples. This latter process was previously studied using coalescent simulations. Our results are in general agreement with the previous method, which provides validation of our approach. Although our model is not an alternative to simulation methods in the practical sense, it provides an algorithm to compute pairwise distributions of alleles, in the case of haploid non-recombining loci such as mitochondrial and Y-chromosome loci in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

A random spatial sampling method in a rural developing nation

Treesearch

Michelle C. Kondo; Kent D.W. Bream; Frances K. Barg; Charles C. Branas

2014-01-01

Nonrandom sampling of populations in developing nations has limitations and can inaccurately estimate health phenomena, especially among hard-to-reach populations such as rural residents. However, random sampling of rural populations in developing nations can be challenged by incomplete enumeration of the base population. We describe a stratified random sampling method...

Systematic Review of the Use of Online Questionnaires among the Geriatric Population

PubMed Central

Remillard, Meegan L.; Mazor, Kathleen M.; Cutrona, Sarah L.; Gurwitz, Jerry H.; Tjia, Jennifer

2014-01-01

Background/Objectives The use of internet-based questionnaires to collect information from older adults is not well established. This systematic literature review of studies using online questionnaires in older adult populations aims to 1. describe methodologic approaches to population targeting and sampling and 2. summarize limitations of Internet-based questionnaires in geriatric populations. Design, Setting, Participants We identified English language articles using search terms for geriatric, age 65 and over, Internet survey, online survey, Internet questionnaire, and online questionnaire in PubMed and EBSCO host between 1984 and July 2012. Inclusion criteria were: study population mean age ≥65 years old and use of an online questionnaire for research. Review of 336 abstracts yielded 14 articles for full review by 2 investigators; 11 articles met inclusion criteria. Measurements Articles were extracted for study design and setting, patient characteristics, recruitment strategy, country, and study limitations. Results Eleven (11) articles were published after 2001. Studies had populations with a mean age of 65 to 78 years, included descriptive and analytical designs, and were conducted in the United States, Australia, and Japan. Recruiting methods varied widely from paper fliers and personal emails to use of consumer marketing panels. Investigator-reported study limitations included the use of small convenience samples and limited generalizability. Conclusion Online questionnaires are a feasible method of surveying older adults in some geographic regions and for some subsets of older adults, but limited Internet access constrains recruiting methods and often limits study generalizability. PMID:24635138

Post-sampling mortality and non-response patterns in the English Cancer Patient Experience Survey: Implications for epidemiological studies based on surveys of cancer patients.

PubMed

Abel, Gary A; Saunders, Catherine L; Lyratzopoulos, Georgios

2016-04-01

Surveys of the experience of cancer patients are increasingly being introduced in different countries and used in cancer epidemiology research. Sampling processes, post-sampling mortality and survey non-response can influence the representativeness of cancer patient surveys. We examined predictors of post-sampling mortality and non-response among patients initially included in the sampling frame of the English Cancer Patient Experience Survey. We also compared the respondents' diagnostic case-mix to other relevant populations of cancer patients, including incident and prevalent cases. Of 109,477 initially sampled cancer patients, 6273 (5.7%) died between sampling and survey mail-out. Older age and diagnosis of brain, lung and pancreatic cancer were associated with higher risk of post-sampling mortality. The overall response rate was 67% (67,713 respondents), being >70% for the most affluent patients and those diagnosed with colon or breast cancer and <50% for Asian or Black patients, those under 35 and those diagnosed with brain cancer. The diagnostic case-mix of respondents varied substantially from incident or prevalent cancer cases. Respondents to the English Cancer Patient Experience Survey represent a population of recently treated cancer survivors. Although patient survey data can provide unique insights for improving cancer care quality, features of survey populations need to be acknowledged when analysing and interpreting findings from studies using such data. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

The Impact of Sampling Schemes on the Site Frequency Spectrum in Nonequilibrium Subdivided Populations

PubMed Central

Städler, Thomas; Haubold, Bernhard; Merino, Carlos; Stephan, Wolfgang; Pfaffelhuber, Peter

2009-01-01

Using coalescent simulations, we study the impact of three different sampling schemes on patterns of neutral diversity in structured populations. Specifically, we are interested in two summary statistics based on the site frequency spectrum as a function of migration rate, demographic history of the entire substructured population (including timing and magnitude of specieswide expansions), and the sampling scheme. Using simulations implementing both finite-island and two-dimensional stepping-stone spatial structure, we demonstrate strong effects of the sampling scheme on Tajima's D (DT) and Fu and Li's D (DFL) statistics, particularly under specieswide (range) expansions. Pooled samples yield average DT and DFL values that are generally intermediate between those of local and scattered samples. Local samples (and to a lesser extent, pooled samples) are influenced by local, rapid coalescence events in the underlying coalescent process. These processes result in lower proportions of external branch lengths and hence lower proportions of singletons, explaining our finding that the sampling scheme affects DFL more than it does DT. Under specieswide expansion scenarios, these effects of spatial sampling may persist up to very high levels of gene flow (Nm > 25), implying that local samples cannot be regarded as being drawn from a panmictic population. Importantly, many data sets on humans, Drosophila, and plants contain signatures of specieswide expansions and effects of sampling scheme that are predicted by our simulation results. This suggests that validating the assumption of panmixia is crucial if robust demographic inferences are to be made from local or pooled samples. However, future studies should consider adopting a framework that explicitly accounts for the genealogical effects of population subdivision and empirical sampling schemes. PMID:19237689

Genetic variation, population structure and linkage disequilibrium in Switchgrass with ISSR, SCoT and EST-SSR markers.

PubMed

Zhang, Yu; Yan, Haidong; Jiang, Xiaomei; Wang, Xiaoli; Huang, Linkai; Xu, Bin; Zhang, Xinquan; Zhang, Lexin

2016-01-01

To evaluate genetic variation, population structure, and the extent of linkage disequilibrium (LD), 134 switchgrass ( Panicum virgatum L.) samples were analyzed with 51 markers, including 16 ISSRs, 20 SCoTs, and 15 EST-SSRs. In this study, a high level of genetic variation was observed in the switchgrass samples and they had an average Nei's gene diversity index (H) of 0.311. A total of 793 bands were obtained, of which 708 (89.28 %) were polymorphic. Using a parameter marker index (MI), the efficiency of the three types of markers (ISSR, SCoT, and EST-SSR) in the study were compared and we found that SCoT had a higher marker efficiency than the other two markers. The 134 switchgrass samples could be divided into two sub-populations based on STRUCTURE, UPGMA clustering, and principal coordinate analyses (PCA), and upland and lowland ecotypes could be separated by UPGMA clustering and PCA analyses. Linkage disequilibrium analysis revealed an average r 2 of 0.035 across all 51 markers, indicating a trend of higher LD in sub-population 2 than that in sub-population 1 ( P  < 0.01). The population structure revealed in this study will guide the design of future association studies using these switchgrass samples.

Chamomile Consumption and Mortality: A Prospective Study of Mexican Origin Older Adults

PubMed Central

Howrey, Bret T.; Peek, M. Kristen; McKee, Juliet M.; Raji, Mukaila A.; Ottenbacher, Kenneth J.; Markides, Kyriakos S.

2016-01-01

Purpose: Approximately 20% of adults use some kind of herbal; however, little data exists from population-based study or clinical trials to support effectiveness of most herbal products. Chamomile is a commonly used herb among older adults of Mexican origin. We examined the effects of herbal chamomile consumption on mortality among older adults of Mexican origin. Methods and Design. A sample from the Hispanic Established Populations for Epidemiologic Study of the Elderly, a population-based study of noninstitutionalized Mexican Americans aged 65 and older from five Southwestern states (Texas, California, New Mexico, Colorado, and Arizona). We included all men and women from 2000 to 2007 (n = 1,677). Results. Chamomile was used by 14% of the sample. Cox proportional hazards regression analyses showed that chamomile was associated with a decreased risk of mortality in the total sample (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.55–0.92) and for women (HR 0.67, 95% CI 0.49–0.92) but not for men. In models adjusted for sociodemographic variables, health behaviors, and chronic conditions, chamomile remained significantly associated with reduced mortality in women (HR 0.72, 95% CI 0.53–0.98). Implications. The use of chamomile shows protective effects against mortality in this sample of older adults of Mexican origin for women. Further research is warranted in other populations to determine if these effects are consistent. PMID:26035879

The 'number needed to sample' in primary care research. Comparison of two primary care sampling frames for chronic back pain.

PubMed

Smith, Blair H; Hannaford, Philip C; Elliott, Alison M; Smith, W Cairns; Chambers, W Alastair

2005-04-01

Sampling for primary care research must strike a balance between efficiency and external validity. For most conditions, even a large population sample will yield a small number of cases, yet other sampling techniques risk problems with extrapolation of findings. To compare the efficiency and external validity of two sampling methods for both an intervention study and epidemiological research in primary care--a convenience sample and a general population sample--comparing the response and follow-up rates, the demographic and clinical characteristics of each sample, and calculating the 'number needed to sample' (NNS) for a hypothetical randomized controlled trial. In 1996, we selected two random samples of adults from 29 general practices in Grampian, for an epidemiological study of chronic pain. One sample of 4175 was identified by an electronic questionnaire that listed patients receiving regular analgesic prescriptions--the 'repeat prescription sample'. The other sample of 5036 was identified from all patients on practice lists--the 'general population sample'. Questionnaires, including demographic, pain and general health measures, were sent to all. A similar follow-up questionnaire was sent in 2000 to all those agreeing to participate in further research. We identified a potential group of subjects for a hypothetical trial in primary care based on a recently published trial (those aged 25-64, with severe chronic back pain, willing to participate in further research). The repeat prescription sample produced better response rates than the general sample overall (86% compared with 82%, P < 0.001), from both genders and from the oldest and youngest age groups. The NNS using convenience sampling was 10 for each member of the final potential trial sample, compared with 55 using general population sampling. There were important differences between the samples in age, marital and employment status, social class and educational level. However, among the potential trial sample, there were no demographic differences. Those from the repeat prescription sample had poorer indices than the general population sample in all pain and health measures. The repeat prescription sampling method was approximately five times more efficient than the general population method. However demographic and clinical differences in the repeat prescription sample might hamper extrapolation of findings to the general population, particularly in an epidemiological study, and demonstrate that simple comparison with age and gender of the target population is insufficient.

Palladium-based Mass-Tag Cell Barcoding with a Doublet-Filtering Scheme and Single Cell Deconvolution Algorithm

PubMed Central

Zunder, Eli R.; Finck, Rachel; Behbehani, Gregory K.; Amir, El-ad D.; Krishnaswamy, Smita; Gonzalez, Veronica D.; Lorang, Cynthia G.; Bjornson, Zach; Spitzer, Matthew H.; Bodenmiller, Bernd; Fantl, Wendy J.; Pe’er, Dana; Nolan, Garry P.

2015-01-01

SUMMARY Mass-tag cell barcoding (MCB) labels individual cell samples with unique combinatorial barcodes, after which they are pooled for processing and measurement as a single multiplexed sample. The MCB method eliminates variability between samples in antibody staining and instrument sensitivity, reduces antibody consumption, and shortens instrument measurement time. Here, we present an optimized MCB protocol with several improvements over previously described methods. The use of palladium-based labeling reagents expands the number of measurement channels available for mass cytometry and reduces interference with lanthanide-based antibody measurement. An error-detecting combinatorial barcoding scheme allows cell doublets to be identified and removed from the analysis. A debarcoding algorithm that is single cell-based rather than population-based improves the accuracy and efficiency of sample deconvolution. This debarcoding algorithm has been packaged into software that allows rapid and unbiased sample deconvolution. The MCB procedure takes 3–4 h, not including sample acquisition time of ~1 h per million cells. PMID:25612231

Estimating population size with correlated sampling unit estimates

Treesearch

David C. Bowden; Gary C. White; Alan B. Franklin; Joseph L. Ganey

2003-01-01

Finite population sampling theory is useful in estimating total population size (abundance) from abundance estimates of each sampled unit (quadrat). We develop estimators that allow correlated quadrat abundance estimates, even for quadrats in different sampling strata. Correlated quadrat abundance estimates based on mark–recapture or distance sampling methods occur...

Population Pharmacokinetics and Optimal Sampling Strategy for Model-Based Precision Dosing of Melphalan in Patients Undergoing Hematopoietic Stem Cell Transplantation.

PubMed

Mizuno, Kana; Dong, Min; Fukuda, Tsuyoshi; Chandra, Sharat; Mehta, Parinda A; McConnell, Scott; Anaissie, Elias J; Vinks, Alexander A

2018-05-01

High-dose melphalan is an important component of conditioning regimens for patients undergoing hematopoietic stem cell transplantation. The current dosing strategy based on body surface area results in a high incidence of oral mucositis and gastrointestinal and liver toxicity. Pharmacokinetically guided dosing will individualize exposure and help minimize overexposure-related toxicity. The purpose of this study was to develop a population pharmacokinetic model and optimal sampling strategy. A population pharmacokinetic model was developed with NONMEM using 98 observations collected from 15 adult patients given the standard dose of 140 or 200 mg/m 2 by intravenous infusion. The determinant-optimal sampling strategy was explored with PopED software. Individual area under the curve estimates were generated by Bayesian estimation using full and the proposed sparse sampling data. The predictive performance of the optimal sampling strategy was evaluated based on bias and precision estimates. The feasibility of the optimal sampling strategy was tested using pharmacokinetic data from five pediatric patients. A two-compartment model best described the data. The final model included body weight and creatinine clearance as predictors of clearance. The determinant-optimal sampling strategies (and windows) were identified at 0.08 (0.08-0.19), 0.61 (0.33-0.90), 2.0 (1.3-2.7), and 4.0 (3.6-4.0) h post-infusion. An excellent correlation was observed between area under the curve estimates obtained with the full and the proposed four-sample strategy (R 2  = 0.98; p < 0.01) with a mean bias of -2.2% and precision of 9.4%. A similar relationship was observed in children (R 2  = 0.99; p < 0.01). The developed pharmacokinetic model-based sparse sampling strategy promises to achieve the target area under the curve as part of precision dosing.

Unsupervised discovery of microbial population structure within metagenomes using nucleotide base composition

PubMed Central

Saeed, Isaam; Tang, Sen-Lin; Halgamuge, Saman K.

2012-01-01

An approach to infer the unknown microbial population structure within a metagenome is to cluster nucleotide sequences based on common patterns in base composition, otherwise referred to as binning. When functional roles are assigned to the identified populations, a deeper understanding of microbial communities can be attained, more so than gene-centric approaches that explore overall functionality. In this study, we propose an unsupervised, model-based binning method with two clustering tiers, which uses a novel transformation of the oligonucleotide frequency-derived error gradient and GC content to generate coarse groups at the first tier of clustering; and tetranucleotide frequency to refine these groups at the secondary clustering tier. The proposed method has a demonstrated improvement over PhyloPythia, S-GSOM, TACOA and TaxSOM on all three benchmarks that were used for evaluation in this study. The proposed method is then applied to a pyrosequenced metagenomic library of mud volcano sediment sampled in southwestern Taiwan, with the inferred population structure validated against complementary sequencing of 16S ribosomal RNA marker genes. Finally, the proposed method was further validated against four publicly available metagenomes, including a highly complex Antarctic whale-fall bone sample, which was previously assumed to be too complex for binning prior to functional analysis. PMID:22180538

Evaluation of limited blood sampling population input approaches for kinetic quantification of [18F]fluorothymidine PET data.

PubMed

Contractor, Kaiyumars B; Kenny, Laura M; Coombes, Charles R; Turkheimer, Federico E; Aboagye, Eric O; Rosso, Lula

2012-03-24

Quantification of kinetic parameters of positron emission tomography (PET) imaging agents normally requires collecting arterial blood samples which is inconvenient for patients and difficult to implement in routine clinical practice. The aim of this study was to investigate whether a population-based input function (POP-IF) reliant on only a few individual discrete samples allows accurate estimates of tumour proliferation using [18F]fluorothymidine (FLT). Thirty-six historical FLT-PET data with concurrent arterial sampling were available for this study. A population average of baseline scans blood data was constructed using leave-one-out cross-validation for each scan and used in conjunction with individual blood samples. Three limited sampling protocols were investigated including, respectively, only seven (POP-IF7), five (POP-IF5) and three (POP-IF3) discrete samples of the historical dataset. Additionally, using the three-point protocol, we derived a POP-IF3M, the only input function which was not corrected for the fraction of radiolabelled metabolites present in blood. The kinetic parameter for net FLT retention at steady state, Ki, was derived using the modified Patlak plot and compared with the original full arterial set for validation. Small percentage differences in the area under the curve between all the POP-IFs and full arterial sampling IF was found over 60 min (4.2%-5.7%), while there were, as expected, larger differences in the peak position and peak height.A high correlation between Ki values calculated using the original arterial input function and all the population-derived IFs was observed (R2 = 0.85-0.98). The population-based input showed good intra-subject reproducibility of Ki values (R2 = 0.81-0.94) and good correlation (R2 = 0.60-0.85) with Ki-67. Input functions generated using these simplified protocols over scan duration of 60 min estimate net PET-FLT retention with reasonable accuracy.

The use of genetics for the management of a recovering population: temporal assessment of migratory peregrine falcons in North America

USGS Publications Warehouse

Johnson, Jeff A.; Talbot, Sandra L.; Sage, George K.; Burnham, Kurt K.; Brown, Joseph W.; Maechtle, Tom L.; Seegar, William S.; Yates, Michael A.; Anderson, Bud; Mindell, David P.

2010-01-01

Background:Our ability to monitor populations or species that were once threatened or endangered and in the process of recovery is enhanced by using genetic methods to assess overall population stability and size over time. This can be accomplished most directly by obtaining genetic measures from temporally-spaced samples that reflect the overall stability of the population as given by changes in genetic diversity levels (allelic richness and heterozygosity), degree of population differentiation (FST and DEST), and effective population size (Ne). The primary goal of any recovery effort is to produce a long-term self-sustaining population, and these measures provide a metric by which we can gauge our progress and help make important management decisions. Methodology/Principal Findings:The peregrine falcon in North America (Falco peregrinus tundrius and anatum) was delisted in 1994 and 1999, respectively, and its abundance will be monitored by the species Recovery Team every three years until 2015. Although the United States Fish and Wildlife Service makes a distinction between tundrius and anatum subspecies, our genetic results based on eleven microsatellite loci, including those from Brown et al. (2007), suggest no differentiation and warrant delineation of a subspecies in its northern latitudinal distribution from Alaska through Canada into Greenland. Using temporal samples collected at Padre Island, Texas during migration (seven temporal time periods between 1985-2007), no significant differences in genetic diversity or significant population differentiation in allele frequencies between time periods were observed and were indistinguishable from those obtained from tundrius/anatum breeding locations throughout their northern distribution. Estimates of harmonic mean Ne were variable and imprecise, but always greater than 500 when employing multiple temporal genetic methods. These results, including those from simulations to assess the power of each method to estimate Ne, suggest a stable population consistent with data from field-based monitoring indicating that this species is stable or continuing to increase in abundance. Therefore, historic and continuing efforts to prevent the extinction of the peregrine falcon in North America appear successful, further highlighting the importance of archiving samples for continual assessment of population recovery and long-term viability.

Population-Based Pediatric Reference Intervals in General Clinical Chemistry: A Swedish Survey.

PubMed

Ridefelt, Peter

2015-01-01

Very few high quality studies on pediatric reference intervals for general clinical chemistry and hematology analytes have been performed. Three recent prospective community-based projects utilising blood samples from healthy children in Sweden, Denmark and Canada have substantially improved the situation. The Swedish survey included 701 healthy children. Reference intervals for general clinical chemistry and hematology were defined.

Childhood Predictors of Male Criminality: A Prospective Population-Based Follow-up Study from Age 8 to Late Adolescence

ERIC Educational Resources Information Center

Sourander, Andre; Elonheimo, Henrik; Niemela, Solja; Nuutila, Ari-Matti; Helenius, Hans; Sillanmaki, Lauri; Piha, Jorma; Tamminen, Tuula; Kumpulainen, Kirsti; Moilanen, Irma; Almqvist, Frederik

2006-01-01

Objective: To study childhood predictors for late adolescence criminality. Method: The follow-up sample included 2,713 Finnish boys born in 1981. Information about the 8-year-old boys' problem behavior was obtained from parents, teachers, and the children themselves. The follow-up information about criminal offenses was based on the national…

The Role of Perceived Control in Explaining Depressive Symptoms Associated with Driving Cessation in a Longitudinal Study

ERIC Educational Resources Information Center

Windsor, Timothy D.; Anstey, Kaarin J.; Butterworth, Peter; Luszcz, Mary A.; Andrews, Gary R.

2007-01-01

Purpose: The purpose of this article was to investigate the role of control beliefs in mediating the relationship between driving cessation and change in depressive symptoms in a population-based sample of older adults. Design and Methods: We report results from a prospective, community-based cohort study that included two waves of data collected…

Transgender Population Size in the United States: a Meta-Regression of Population-Based Probability Samples

PubMed Central

Sevelius, Jae M.

2017-01-01

Background. Transgender individuals have a gender identity that differs from the sex they were assigned at birth. The population size of transgender individuals in the United States is not well-known, in part because official records, including the US Census, do not include data on gender identity. Population surveys today more often collect transgender-inclusive gender-identity data, and secular trends in culture and the media have created a somewhat more favorable environment for transgender people. Objectives. To estimate the current population size of transgender individuals in the United States and evaluate any trend over time. Search methods. In June and July 2016, we searched PubMed, Cumulative Index to Nursing and Allied Health Literature, and Web of Science for national surveys, as well as “gray” literature, through an Internet search. We limited the search to 2006 through 2016. Selection criteria. We selected population-based surveys that used probability sampling and included self-reported transgender-identity data. Data collection and analysis. We used random-effects meta-analysis to pool eligible surveys and used meta-regression to address our hypothesis that the transgender population size estimate would increase over time. We used subsample and leave-one-out analysis to assess for bias. Main results. Our meta-regression model, based on 12 surveys covering 2007 to 2015, explained 62.5% of model heterogeneity, with a significant effect for each unit increase in survey year (F = 17.122; df = 1,10; b = 0.026%; P = .002). Extrapolating these results to 2016 suggested a current US population size of 390 adults per 100 000, or almost 1 million adults nationally. This estimate may be more indicative for younger adults, who represented more than 50% of the respondents in our analysis. Authors’ conclusions. Future national surveys are likely to observe higher numbers of transgender people. The large variety in questions used to ask about transgender identity may account for residual heterogeneity in our models. Public health implications. Under- or nonrepresentation of transgender individuals in population surveys is a barrier to understanding social determinants and health disparities faced by this population. We recommend using standardized questions to identify respondents with transgender and nonbinary gender identities, which will allow a more accurate population size estimate. PMID:28075632

Ural Eye and Medical Study: description of study design and methodology.

PubMed

Bikbov, Mukharram; Fayzrakhmanov, Rinat R; Kazakbaeva, Gyulli; Jonas, Jost B

2018-06-01

Since there is a scarcity on population-based health information available for Russia, we conducted this project to assess the prevalence of major ocular and systemic disorders and their associated risk factors. A population-based cross-sectional study (Ural Eye and Medical Study (UEMS)) was performed in Bashkortostan 1300 km east of Moscow. The sampling frame consisted of all inhabitants aged over 40 years and living in an urban study area in the capital city Ufa and a rural region at 65 km outside of Ufa. The target sample size was 2500 individuals for the urban region and 2500 persons for the rural region. The study participants underwent a detailed interview, a detailed ophthalmologic examination including biometry and optical coherence tomography, and clinical examination including assessment of electrocardiography, hearing test, blood sampling, spirometry, and hand grip dynamometry. After a first study period, the study population included 4254 individuals with a mean age of 60.3 ± 11.1 years (range: 40-94 years), mean body weight of 74.8 ± 14.4 kg (range: 31-170 kg), body height of 163.6 ± 8.9 cm (range: 112-196), body mass index of 28.0 ± 5.1 kg/m 2 (range: 13.96-60.96 kg/m 2 ), mean systolic blood pressure of 133.7 ± 21.0 mmHg (range: 84-232 mmHg), and mean diastolic blood pressure of 81.2 ± 10.6 mmHg (range: 40-134 mmHg). Mean refractive error was -0.21 ± 1.94 D and mean intraocular pressure was 13.6 ± 3.9 mmHg. The UEMS provides population-based normative data for a Russian region on the quantitative traits such as axial length, quality of life and lifestyle including smoking and alcohol consumption, and prevalence and risk factors of ocular and systemic diseases such as diabetes mellitus, arterial hypertension, chronic obstructive pulmonary disease, and depression.

Classifying sensory profiles of children in the general population.

PubMed

Little, L M; Dean, E; Tomchek, S D; Dunn, W

2017-01-01

The aim of this study was to subtype groups of children in a community sample with and without developmental conditions, based on sensory processing patterns. We used latent profile analysis to determine the number of sensory subtypes in a sample of n = 1132 children aged 3-14 years with typical development and developmental conditions, including autism spectrum disorder (ASD), attention-deficit hyperactivity disorder and learning disabilities. A five-subtype solution was found to best characterize the sample, which differed on overall degree and differential presentation of sensory processing patterns. Children with and without developmental conditions presented across subtypes, and one subtype was significantly younger in age than others (P < 0.05). Our results show that sensory subtypes include both children with typical development and those with developmental conditions. Sensory subtypes have previously been investigated in ASD only, and our results suggest that similar sensory subtypes are present in a sample reflective of the general population of children including those largely with typical development. Elevated scores on sensory processing patterns are not unique to ASD but rather are reflections of children's abilities to respond to environmental demands. © 2016 John Wiley & Sons Ltd.

A population-based nested case control study on recurrent pneumonias in children with severe generalized cerebral palsy: ethical considerations of the design and representativeness of the study sample.

PubMed

Veugelers, Rebekka; Calis, Elsbeth A C; Penning, Corine; Verhagen, Arianne; Bernsen, Roos; Bouquet, Jan; Benninga, Marc A; Merkus, Peter J F M; Arets, Hubertus G M; Tibboel, Dick; Evenhuis, Heleen M

2005-07-19

In children with severe generalized cerebral palsy, pneumonias are a major health issue. Malnutrition, dysphagia, gastro-oesophageal reflux, impaired respiratory function and constipation are hypothesized risk factors. Still, no data are available on the relative contribution of these possible risk factors in the described population. This paper describes the initiation of a study in 194 children with severe generalized cerebral palsy, on the prevalence and on the impact of these hypothesized risk factors of recurrent pneumonias. A nested case-control design with 18 months follow-up was chosen. Dysphagia, respiratory function and constipation will be assessed at baseline, malnutrition and gastro-oesophageal reflux at the end of the follow-up. The study population consists of a representative population sample of children with severe generalized cerebral palsy. Inclusion was done through care-centres in a predefined geographical area and not through hospitals. All measurements will be done on-site which sets high demands on all measurements. If these demands were not met in "gold standard" methods, other methods were chosen. Although the inclusion period was prolonged, the desired sample size of 300 children was not met. With a consent rate of 33%, nearly 10% of all eligible children in The Netherlands are included (n = 194). The study population is subtly different from the non-participants with regard to severity of dysphagia and prevalence rates of pneumonias and gastro-oesophageal reflux. Ethical issues complicated the study design. Assessment of malnutrition and gastro-oesophageal reflux at baseline was considered unethical, since these conditions can be easily treated. Therefore, we postponed these diagnostics until the end of the follow-up. In order to include a representative sample, all eligible children in a predefined geographical area had to be contacted. To increase the consent rate, on-site measurements are of first choice, but timely inclusion is jeopardized. The initiation of this first study among children with severe neurological impairment led to specific, unexpected problems. Despite small differences between participants and non-participating children, our sample is as representative as can be expected from any population-based study and will provide important, new information to bring us further towards effective interventions to prevent pneumonias in this population.

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

Treesearch

H. T. Schreuder; M. S. Williams

2000-01-01

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

Is urbanisation scrambling the genetic structure of human populations? A case study

PubMed Central

Ashrafian-Bonab, Maziar; Handley, Lori Lawson; Balloux, François

2007-01-01

Recent population expansion and increased migration linked to urbanisation are assumed to be eroding the genetic structure of human populations. We investigated change in population structure over three generations by analysing both demographic and mitochondrial DNA (mtDNA) data from a random sample of 2351 men from twenty-two Iranian populations. Potential changes in genetic diversity (θ) and genetic distance (FST) over the last three generations were analysed by assigning mtDNA sequences to populations based on the individual's place of birth or that of their mother or grandmother. Despite the fact that several areas included cities of over one million inhabitants, we detected no change in genetic diversity, and only a small decrease in population structure, except in the capital city (Tehran), which was characterised by massive immigration, increased θ and a large decrease in FST over time. Our results suggest that recent erosion of human population structure might not be as important as previously thought, except in some large conurbations, and this clearly has important implications for future sampling strategies. PMID:17106453

Multilocus nuclear DNA markers reveal population structure and demography of Anopheles minimus.

PubMed

Dixit, Jyotsana; Arunyawat, Uraiwan; Huong, Ngo Thi; Das, Aparup

2014-11-01

Utilization of multiple putatively neutral DNA markers for inferring evolutionary history of species population is considered to be the most robust approach. Molecular population genetic studies have been conducted in many species of Anopheles genus, but studies based on single nucleotide polymorphism (SNP) data are still very scarce. Anopheles minimus is one of the principal malaria vectors of Southeast (SE) Asia including the Northeastern (NE) India. Although population genetic studies with mitochondrial genetic variation data have been utilized to infer phylogeography of the SE Asian populations of this species, limited information on the population structure and demography of Indian An. minimus is available. We herewith have developed multilocus nuclear genetic approach with SNP markers located in X chromosome of An. minimus in eight Indian and two SE Asian population samples (121 individual mosquitoes in total) to infer population history and test several hypotheses on the phylogeography of this species. While the Thai population sample of An. minimus presented the highest nucleotide diversity, majority of the Indian samples were also fairly diverse. In general, An. minimus populations were moderately substructured in the distribution range covering SE Asia and NE India, largely falling under three distinct genetic clusters. Moreover, demographic expansion events could be detected in the majority of the presently studied populations of An. minimus. Additional DNA sequencing of the mitochondrial COII region in a subset of the samples (40 individual mosquitoes) corroborated the existing hypothesis of Indian An. minimus falling under the earlier reported mitochondrial lineage B. © 2014 John Wiley & Sons Ltd.

Altered self-perception in adult survivors treated for a CNS tumor in childhood or adolescence: population-based outcomes compared with the general population

PubMed Central

Hörnquist, Lina; Rickardsson, Jenny; Lannering, Birgitta; Gustafsson, Göran; Boman, Krister K.

2015-01-01

Background Survivors of pediatric CNS tumors are at risk for persistent tumor/treatment-related morbidity, physical disability and social consequences that may alter self-perception, vital for self-identity, mental health and quality of survival. We studied the long-term impact of childhood CNS tumors and their treatment on the self-perception of adult survivors and compared outcomes with those of the general population. Methods The cohort included 697 Swedish survivors diagnosed with a primary CNS tumor during 1982–2001. Comparison data were randomly collected from a stratified general population sample. Survivors and general population individuals were compared as regards self-perception in 5 domains: body image, sports/physical activities, peers, work, and family, and with a global self-esteem index. Within the survivor group, determinants of impact on self-perception were identified. Results The final analyzed sample included 528 survivors, 75.8% of the entire national cohort. The control sample consisted of 995, 41% of 2500 addressed. Survivors had significantly poorer self-perception outcomes in domains of peers, work, body image, and sports/physical activities, and in the global self-perception measure, compared with those of the general population (all P < .001). Within the survivor group, female gender and persistent visible physical sequelae predicted poorer outcomes in several of the studied domains. Tumor type and a history of cranial radiation therapy were associated with outcomes. Conclusion An altered self-perception is a potential late effect in adult survivors of pediatric CNS tumors. Self-perception and self-esteem are significant elements of identity, mental health and quality of survival. Therefore, care and psychosocial follow-up of survivors should include measures for identifying disturbances and for assessing the need for psychosocial intervention. PMID:25332406

Prevalence, clinical features and risk assessment of pre-diabetes in Spain: the prospective Mollerussa cohort study

PubMed Central

Vilanova, María Belén; Falguera, Mireia; Marsal, Josep Ramon; Rubinat, Esther; Alcubierre, Núria; Catelblanco, Esmeralda; Granado-Casas, Minerva; Miró, Neus; Molló, Àngels; Mata-Cases, Manel; Franch-Nadal, Josep; Mauricio, Didac

2017-01-01

Purpose The Mollerussa prospective cohort was created to study pre-diabetes in a population-based sample from the primary care setting in the semirural area of Pla d’Urgell in Catalonia (Spain). The aims of the study were to assess the prevalence of pre-diabetes in our population, the likelihood to develop overt diabetes over time and to identify risk factors associated with the progression of the condition. Participants The cohort includes 594 subjects randomly selected between March 2011 and July 2014 from our primary care population, who were older than 25 years, consented to participate and did not have a recorded diagnosis of diabetes. Findings to date At baseline, we performed a clinical interview to collect demographic, clinical and lifestyle (including a nutritional survey) characteristics; carotid ultrasound imaging to assess subclinical cardiovascular disease was also performed, and a blood sample was collected, with an overall <5% rate of missing data. An additional blood draw was performed 12 months after initial recruitment to reassess laboratory results in patients initially identified as having pre-diabetes, with an 89.6% retention rate. Several studies investigating various hypotheses are currently ongoing. Future plans All subjects recruited during the cohort creation will be followed long-term through annual extraction of data from health records stored in the electronic Clinical station in Primary Care database. The Mollerussa cohort will thus be a sound population-based sample for multiple future research projects to generate insights into the epidemiology and natural history of pre-diabetes in Spain. PMID:28606902

Variation in the cranial base orientation and facial skeleton in dry skulls sampled from three major populations.

PubMed

Kuroe, Kazuto; Rosas, Antonio; Molleson, Theya

2004-04-01

The aim of this study was to analyse the effects of cranial base orientation on the morphology of the craniofacial system in human populations. Three geographically distant populations from Europe (72), Africa (48) and Asia (24) were chosen. Five angular and two linear variables from the cranial base component and six angular and six linear variables from the facial component based on two reference lines of the vertical posterior maxillary and Frankfort horizontal planes were measured. The European sample presented dolichofacial individuals with a larger face height and a smaller face depth derived from a raised cranial base and facial cranium orientation which tended to be similar to the Asian sample. The African sample presented brachyfacial individuals with a reduced face height and a larger face depth as a result of a lowered cranial base and facial cranium orientation. The Asian sample presented dolichofacial individuals with a larger face height and depth due to a raised cranial base and facial cranium orientation. The findings of this study suggest that cranial base orientation and posterior cranial base length appear to be valid discriminating factors between different human populations.

A survey sampling approach for pesticide monitoring of community water systems using groundwater as a drinking water source.

PubMed

Whitmore, Roy W; Chen, Wenlin

2013-12-04

The ability to infer human exposure to substances from drinking water using monitoring data helps determine and/or refine potential risks associated with drinking water consumption. We describe a survey sampling approach and its application to an atrazine groundwater monitoring study to adequately characterize upper exposure centiles and associated confidence intervals with predetermined precision. Study design and data analysis included sampling frame definition, sample stratification, sample size determination, allocation to strata, analysis weights, and weighted population estimates. Sampling frame encompassed 15 840 groundwater community water systems (CWS) in 21 states throughout the U. S. Median, and 95th percentile atrazine concentrations were 0.0022 and 0.024 ppb, respectively, for all CWS. Statistical estimates agreed with historical monitoring results, suggesting that the study design was adequate and robust. This methodology makes no assumptions regarding the occurrence distribution (e.g., lognormality); thus analyses based on the design-induced distribution provide the most robust basis for making inferences from the sample to target population.

[The research protocol III. Study population].

PubMed

Arias-Gómez, Jesús; Villasís-Keever, Miguel Ángel; Miranda-Novales, María Guadalupe

2016-01-01

The study population is defined as a set of cases, determined, limited, and accessible, that will constitute the subjects for the selection of the sample, and must fulfill several characteristics and distinct criteria. The objectives of this manuscript are focused on specifying each one of the elements required to make the selection of the participants of a research project, during the elaboration of the protocol, including the concepts of study population, sample, selection criteria and sampling methods. After delineating the study population, the researcher must specify the criteria that each participant has to comply. The criteria that include the specific characteristics are denominated selection or eligibility criteria. These criteria are inclusion, exclusion and elimination, and will delineate the eligible population. The sampling methods are divided in two large groups: 1) probabilistic or random sampling and 2) non-probabilistic sampling. The difference lies in the employment of statistical methods to select the subjects. In every research, it is necessary to establish at the beginning the specific number of participants to be included to achieve the objectives of the study. This number is the sample size, and can be calculated or estimated with mathematical formulas and statistic software.

Infant and toddler disease score was useful for risk of hospitalization based on data from administrative claims.

PubMed

Mikaeloff, Yann; Moride, Yola; Khoshnood, Babak; Weill, Alain; Bréart, Gérard

2007-07-01

To develop the infant and toddler disease score (IDS), a population-based predictive tool of morbidity status in infants and toddlers, based on data from administrative claims. A prospective cohort study was conducted, including 35,580 children less than 2 years of age in June 2003 from the French "ERASME" database (mean follow-up 13 months). The outcome variable was incident hospitalization during the follow-up year, that is, before the second birthday for infants and before the third for toddlers. Risk factors before inclusion (age, health care use, medications) were assessed in a 50% random sample (construction sample) by a logistic regression model. Beta coefficients were summed up to obtain the IDS. The IDS was then validated for the remaining 50% of the study population (validation sample). The major variables significantly associated with the outcome were long-term disability, younger age, and >or=1 hospitalization before inclusion. The risks of hospitalization estimated by the IDS were concordant in the construction and validation samples. The IDS is a useful index for the risk of hospitalization of infants and toddlers in relation to their morbidity status and may be used for adjustment in pharmacoepidemiologic studies using administrative claims databases.

Active animal health surveillance in European Union Member States: gaps and opportunities.

PubMed

Bisdorff, B; Schauer, B; Taylor, N; Rodríguez-Prieto, V; Comin, A; Brouwer, A; Dórea, F; Drewe, J; Hoinville, L; Lindberg, A; Martinez Avilés, M; Martínez-López, B; Peyre, M; Pinto Ferreira, J; Rushton, J; VAN Schaik, G; Stärk, K D C; Staubach, C; Vicente-Rubiano, M; Witteveen, G; Pfeiffer, D; Häsler, B

2017-03-01

Animal health surveillance enables the detection and control of animal diseases including zoonoses. Under the EU-FP7 project RISKSUR, a survey was conducted in 11 EU Member States and Switzerland to describe active surveillance components in 2011 managed by the public or private sector and identify gaps and opportunities. Information was collected about hazard, target population, geographical focus, legal obligation, management, surveillance design, risk-based sampling, and multi-hazard surveillance. Two countries were excluded due to incompleteness of data. Most of the 664 components targeted cattle (26·7%), pigs (17·5%) or poultry (16·0%). The most common surveillance objectives were demonstrating freedom from disease (43·8%) and case detection (26·8%). Over half of components applied risk-based sampling (57·1%), but mainly focused on a single population stratum (targeted risk-based) rather than differentiating between risk levels of different strata (stratified risk-based). About a third of components were multi-hazard (37·3%). Both risk-based sampling and multi-hazard surveillance were used more frequently in privately funded components. The study identified several gaps (e.g. lack of systematic documentation, inconsistent application of terminology) and opportunities (e.g. stratified risk-based sampling). The greater flexibility provided by the new EU Animal Health Law means that systematic evaluation of surveillance alternatives will be required to optimize cost-effectiveness.

HELIOSEISMOLOGY OF PRE-EMERGING ACTIVE REGIONS. I. OVERVIEW, DATA, AND TARGET SELECTION CRITERIA

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

Leka, K. D.; Barnes, G.; Birch, A. C.

2013-01-10

This first paper in a series describes the design of a study testing whether pre-appearance signatures of solar magnetic active regions were detectable using various tools of local helioseismology. The ultimate goal is to understand flux-emergence mechanisms by setting observational constraints on pre-appearance subsurface changes, for comparison with results from simulation efforts. This first paper provides details of the data selection and preparation of the samples, each containing over 100 members, of two populations: regions on the Sun that produced a numbered NOAA active region, and a 'control' sample of areas that did not. The seismology is performed on datamore » from the GONG network; accompanying magnetic data from SOHO/MDI are used for co-temporal analysis of the surface magnetic field. Samples are drawn from 2001-2007, and each target is analyzed for 27.7 hr prior to an objectively determined time of emergence. The results of two analysis approaches are published separately: one based on averages of the seismology- and magnetic-derived signals over the samples, another based on Discriminant Analysis of these signals, for a statistical test of detectable differences between the two populations. We include here descriptions of a new potential-field calculation approach and the algorithm for matching sample distributions over multiple variables. We describe known sources of bias and the approaches used to mitigate them. We also describe unexpected bias sources uncovered during the course of the study and include a discussion of refinements that should be included in future work on this topic.« less

Predictors of Disordered Eating in Adolescence and Young Adulthood: A Population-Based, Longitudinal Study of Females and Males in Norway

ERIC Educational Resources Information Center

Abebe, Dawit Shawel; Torgersen, Leila; Lien, Lars; Hafstad, Gertrud S.; von Soest, Tilmann

2014-01-01

We investigated longitudinal predictors for disordered eating from early adolescence to young adulthood (12-34 years) across gender and different developmental phases among Norwegian young people. Survey data from a population-based sample were collected at four time points (T) over a 13-year time span. A population-based sample of 5,679 females…

Are captive tortoises a reservoir for conservation? An assessment of genealogical affiliation of captive Gopherus agassizii to local, wild populations

USGS Publications Warehouse

Berry, Kristin H.; Edwards, Taylor

2013-01-01

The conservation of tortoises poses a unique situation because several threatened species are commonly kept as pets within their native ranges. Thus, there is potential for captive populations to be a reservoir for repatriation efforts. We assess the utility of captive populations of the threatened Agassiz’s desert tortoise (Gopherus agassizii) for recovery efforts based on genetic affinity to local areas. We collected samples from 130 captive desert tortoises from three desert communities: two in California (Ridgecrest and Joshua Tree) and the Desert Tortoise Conservation Center (Las Vegas) in Nevada. We tested all samples for 25 short tandem repeats and sequenced 1,109 bp of the mitochondrial genome. We compared captive genotypes to a database of 1,258 Gopherus samples, including 657 wild caught G. agassizii spanning the full range of the species. We conducted population assignment tests to determine the genetic origins of the captive individuals. For our total sample set, only 44 % of captive individuals were assigned to local populations based on genetic units derived from the reference database. One individual from Joshua Tree, California, was identified as being a Morafka’s desert tortoise, G. morafkai, a cryptic species which is not native to the Mojave Desert. Our data suggest that captive desert tortoises kept within the native range of G. agassizii cannot be presumed to have a genealogical affiliation to wild tortoises in their geographic proximity. Precautions should be taken before considering the release of captive tortoises into the wild as a management tool for recovery.

Prevalence and Predictors of Sexual Risks Among Homeless Youth

ERIC Educational Resources Information Center

Halcon, Linda L.; Lifson, Alan R.

2004-01-01

This study examined prevalence of sexual risks among homeless adolescents and described factors associated with those risks. Community-based outreach methods were used successfully to access this difficult-to-reach population. The sample included 203 homeless youth aged 15-22 recruited from community sites. Questionnaire items addressed…

Population continuity vs. discontinuity revisited: dental affinities among late Paleolithic through Christian-era Nubians.

PubMed

Irish, Joel D

2005-11-01

The present study revisits a subject that has been a source of long-standing bioarchaeological contention, namely, estimation of Nubian population origins and affinities. Using the Arizona State University dental anthropology system, frequencies of 36 crown, root, and intraoral osseous discrete traits in 12 late Pleistocene through early historic Nubian samples were recorded and analyzed. Specifically, intersample phenetic affinities, and an indication of which traits are most important in driving this variation, were determined through the application of correspondence analysis and the mean measure of divergence distance statistic. The results support previous work by the author and others indicating that population discontinuity, in the form of replacement or significant gene flow into an existing gene pool, occurred sometime after the Pleistocene. This analysis now suggests that the break occurred before the Final Neolithic. Samples from the latter through Christian periods exhibit relative homogeneity, which implies overall post-Pleistocene diachronic and regional population continuity. Yet there are several perceptible trends among these latter samples that: 1) are consistent with documented Nubian population history, 2) enable the testing of several existing peopling hypotheses, and 3) allow the formulation of new hypotheses, including a suggestion of two post-Pleistocene subgroups predicated on an age-based sample dichotomy. Copyright 2005 Wiley-Liss, Inc

Assessing polar bear (Ursus maritimus) population structure in the Hudson Bay region using SNPs.

PubMed

Viengkone, Michelle; Derocher, Andrew Edward; Richardson, Evan Shaun; Malenfant, René Michael; Miller, Joshua Moses; Obbard, Martyn E; Dyck, Markus G; Lunn, Nick J; Sahanatien, Vicki; Davis, Corey S

2016-12-01

Defining subpopulations using genetics has traditionally used data from microsatellite markers to investigate population structure; however, single-nucleotide polymorphisms (SNPs) have emerged as a tool for detection of fine-scale structure. In Hudson Bay, Canada, three polar bear ( Ursus maritimus ) subpopulations (Foxe Basin (FB), Southern Hudson Bay (SH), and Western Hudson Bay (WH)) have been delineated based on mark-recapture studies, radiotelemetry and satellite telemetry, return of marked animals in the subsistence harvest, and population genetics using microsatellites. We used SNPs to detect fine-scale population structure in polar bears from the Hudson Bay region and compared our results to the current designations using 414 individuals genotyped at 2,603 SNPs. Analyses based on discriminant analysis of principal components (DAPC) and STRUCTURE support the presence of four genetic clusters: (i) Western-including individuals sampled in WH, SH (excluding Akimiski Island in James Bay), and southern FB (south of Southampton Island); (ii) Northern-individuals sampled in northern FB (Baffin Island) and Davis Strait (DS) (Labrador coast); (iii) Southeast-individuals from SH (Akimiski Island in James Bay); and (iv) Northeast-individuals from DS (Baffin Island). Population structure differed from microsatellite studies and current management designations demonstrating the value of using SNPs for fine-scale population delineation in polar bears.

Nonprobability and probability-based sampling strategies in sexual science.

PubMed

Catania, Joseph A; Dolcini, M Margaret; Orellana, Roberto; Narayanan, Vasudah

2015-01-01

With few exceptions, much of sexual science builds upon data from opportunistic nonprobability samples of limited generalizability. Although probability-based studies are considered the gold standard in terms of generalizability, they are costly to apply to many of the hard-to-reach populations of interest to sexologists. The present article discusses recent conclusions by sampling experts that have relevance to sexual science that advocates for nonprobability methods. In this regard, we provide an overview of Internet sampling as a useful, cost-efficient, nonprobability sampling method of value to sex researchers conducting modeling work or clinical trials. We also argue that probability-based sampling methods may be more readily applied in sex research with hard-to-reach populations than is typically thought. In this context, we provide three case studies that utilize qualitative and quantitative techniques directed at reducing limitations in applying probability-based sampling to hard-to-reach populations: indigenous Peruvians, African American youth, and urban men who have sex with men (MSM). Recommendations are made with regard to presampling studies, adaptive and disproportionate sampling methods, and strategies that may be utilized in evaluating nonprobability and probability-based sampling methods.

What does the fox say? Monitoring antimicrobial resistance in the environment using wild red foxes as an indicator.

PubMed

Mo, Solveig Sølverød; Urdahl, Anne Margrete; Madslien, Knut; Sunde, Marianne; Nesse, Live L; Slettemeås, Jannice Schau; Norström, Madelaine

2018-01-01

The objective of this study was to estimate and compare the occurrence of AMR in wild red foxes in relation to human population densities. Samples from wild red foxes (n = 528) included in the Norwegian monitoring programme on antimicrobial resistance in bacteria from food, feed and animals were included. All samples were divided into three different groups based on population density in the municipality where the foxes were hunted. Of the 528 samples included, 108 (20.5%), 328 (62.1%) and 92 (17.4%) originated from areas with low, medium and high population density, respectively. A single faecal swab was collected from each fox. All samples were plated out on a selective medium for Enterobacteriaceae for culturing followed by inclusion and susceptibility testing of one randomly selected Escherichia coli to assess the overall occurrence of AMR in the Gram-negative bacterial population. Furthermore, the samples were subjected to selective screening for detection of E. coli displaying resistance towards extended-spectrum cephalosporins and fluoroquinolones. In addition, a subset of samples (n = 387) were subjected to selective culturing to detect E. coli resistant to carbapenems and colistin, and enterococci resistant to vancomycin. Of these, 98 (25.3%), 200 (51.7%) and 89 (23.0%) originated from areas with low, medium and high population density, respectively. Overall, the occurrence of AMR in indicator E. coli from wild red foxes originating from areas with different human population densities in Norway was low to moderate (8.8%). The total occurrence of AMR was significantly higher; χ2 (1,N = 336) = 6.53, p = 0.01 in areas with high population density compared to areas with medium population density. Similarly, the occurrence of fluoroquinolone resistant E. coli isolated using selective detection methods was low in areas with low population density and more common in areas with medium or high population density. In conclusion, we found indications that occurrence of AMR in wild red foxes in Norway is associated with human population density. Foxes living in urban areas are more likely to be exposed to AMR bacteria and resistance drivers from food waste, garbage, sewage, waste water and consumption of contaminated prey compared to foxes living in remote areas. The homerange of red fox has been shown to be limited thereby the red fox constitutes a good sentinel for monitoring antimicrobial resistance in the environment. Continuous monitoring on the occurrence of AMR in different wild species, ecological niches and geographical areas can facilitate an increased understanding of the environmental burden of AMR in the environment. Such information is needed to further assess the impact for humans, and enables implementation of possible control measures for AMR in humans, animals and the environment in a true "One Health" approach.

Genetic analysis of Mexican Criollo cattle populations.

PubMed

Ulloa-Arvizu, R; Gayosso-Vázquez, A; Ramos-Kuri, M; Estrada, F J; Montaño, M; Alonso, R A

2008-10-01

The objective of this study was to evaluate the genetic structure of Mexican Criollo cattle populations using microsatellite genetic markers. DNA samples were collected from 168 animals from four Mexican Criollo cattle populations, geographically isolated in remote areas of Sierra Madre Occidental (West Highlands). Also were included samples from two breeds with Iberian origin: the fighting bull (n = 24) and the milking central American Criollo (n = 24) and one Asiatic breed: Guzerat (n = 32). Genetic analysis consisted of the estimation of the genetic diversity in each population by the allele number and the average expected heterozygosity found in nine microsatellite loci. Furthermore, genetic relationships among the populations were defined by their genetic distances. Our data shows that Mexican cattle populations have a relatively high level of genetic diversity based either on the mean number of alleles (10.2-13.6) and on the expected heterozygosity (0.71-0.85). The degree of observed homozygosity within the Criollo populations was remarkable and probably caused by inbreeding (reduced effective population size) possibly due to reproductive structure within populations. Our data shows that considerable genetic differentiation has been occurred among the Criollo cattle populations in different regions of Mexico.

A GHEP-ISFG collaborative study on the genetic variation of 38 autosomal indels for human identification in different continental populations.

PubMed

Pereira, R; Alves, C; Aler, M; Amorim, A; Arévalo, C; Betancor, E; Braganholi, D; Bravo, M L; Brito, P; Builes, J J; Burgos, G; Carvalho, E F; Castillo, A; Catanesi, C I; Cicarelli, R M B; Coufalova, P; Dario, P; D'Amato, M E; Davison, S; Ferragut, J; Fondevila, M; Furfuro, S; García, O; Gaviria, A; Gomes, I; González, E; Gonzalez-Liñan, A; Gross, T E; Hernández, A; Huang, Q; Jiménez, S; Jobim, L F; López-Parra, A M; Marino, M; Marques, S; Martínez-Cortés, G; Masciovecchio, V; Parra, D; Penacino, G; Pinheiro, M F; Porto, M J; Posada, Y; Restrepo, C; Ribeiro, T; Rubio, L; Sala, A; Santurtún, A; Solís, L S; Souto, L; Streitemberger, E; Torres, A; Vilela-Lamego, C; Yunis, J J; Yurrebaso, I; Gusmão, L

2018-01-01

A collaborative effort was carried out by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) to promote knowledge exchange between associate laboratories interested in the implementation of indel-based methodologies and build allele frequency databases of 38 indels for forensic applications. These databases include populations from different countries that are relevant for identification and kinship investigations undertaken by the participating laboratories. Before compiling population data, participants were asked to type the 38 indels in blind samples from annual GHEP-ISFG proficiency tests, using an amplification protocol previously described. Only laboratories that reported correct results contributed with population data to this study. A total of 5839 samples were genotyped from 45 different populations from Africa, America, East Asia, Europe and Middle East. Population differentiation analysis showed significant differences between most populations studied from Africa and America, as well as between two Asian populations from China and East Timor. Low F ST values were detected among most European populations. Overall diversities and parameters of forensic efficiency were high in populations from all continents. Copyright © 2017 Elsevier B.V. All rights reserved.

Recruiting hard-to-reach United States population sub-groups via adaptations of snowball sampling strategy

PubMed Central

Sadler, Georgia Robins; Lee, Hau-Chen; Seung-Hwan Lim, Rod; Fullerton, Judith

2011-01-01

Nurse researchers and educators often engage in outreach to narrowly defined populations. This article offers examples of how variations on the snowball sampling recruitment strategy can be applied in the creation of culturally appropriate, community-based information dissemination efforts related to recruitment to health education programs and research studies. Examples from the primary author’s program of research are provided to demonstrate how adaptations of snowball sampling can be effectively used in the recruitment of members of traditionally underserved or vulnerable populations. The adaptation of snowball sampling techniques, as described in this article, helped the authors to gain access to each of the more vulnerable population groups of interest. The use of culturally sensitive recruitment strategies is both appropriate and effective in enlisting the involvement of members of vulnerable populations. Adaptations of snowball sampling strategies should be considered when recruiting participants for education programs or subjects for research studies when recruitment of a population based sample is not essential. PMID:20727089

Recruitment of hard-to-reach population subgroups via adaptations of the snowball sampling strategy.

PubMed

Sadler, Georgia Robins; Lee, Hau-Chen; Lim, Rod Seung-Hwan; Fullerton, Judith

2010-09-01

Nurse researchers and educators often engage in outreach to narrowly defined populations. This article offers examples of how variations on the snowball sampling recruitment strategy can be applied in the creation of culturally appropriate, community-based information dissemination efforts related to recruitment to health education programs and research studies. Examples from the primary author's program of research are provided to demonstrate how adaptations of snowball sampling can be used effectively in the recruitment of members of traditionally underserved or vulnerable populations. The adaptation of snowball sampling techniques, as described in this article, helped the authors to gain access to each of the more-vulnerable population groups of interest. The use of culturally sensitive recruitment strategies is both appropriate and effective in enlisting the involvement of members of vulnerable populations. Adaptations of snowball sampling strategies should be considered when recruiting participants for education programs or for research studies when the recruitment of a population-based sample is not essential.

Prevalence of depressive disorders in the elderly.

PubMed

Barua, Ankur; Ghosh, Mihir Kumar; Kar, Nilamadhab; Basilio, Mary Anne

2011-01-01

Community-based mental health studies have revealed that the point prevalence of depressive disorders in the elderly population of the world varies between 10% and 20%, depending on cultural situations. A retrospective study based on analysis of various study reports was conducted, to determine the median prevalence rates of depressive disorders in the elderly population of India and various other countries in the world. All the studies that constituted the sample were conducted between 1955 and 2005. Included are only community-based, cross-sectional surveys and some prospective studies that had not excluded depression at baseline. These studies were conducted on a homogenous community of the elderly population in the world, who were selected by a simple random sampling technique. After applying the inclusion and exclusion criteria on published and indexed articles, 74 original research studies that surveyed a total of 487,275 elderly individuals, in the age group of 60 years and above, residing in various parts of the world, were included for the final analysis. The median prevalence rate and its corresponding interquartile range were calculated. The chi-square test and chi-square for linear trend were applied. A P value of <.05 was considered as statistically significant. The median prevalence rate of depressive disorders in the world for the elderly population was determined to be 10.3% (interquartile range [IQR], 4.7%-16.0%). The median prevalence rate of depression among the elderly Indian population was determined to be 21.9% (IQR, 11.6%-31.1%). Although there was a significant decrease in the trend of world prevalence of geriatric depression, it was significantly higher among Indians, in recent years, than the rest of the world.

Successful collection of stool samples for microbiome analyses from a large community-based population of elderly men.

PubMed

Abrahamson, Melanie; Hooker, Elizabeth; Ajami, Nadim J; Petrosino, Joseph F; Orwoll, Eric S

2017-09-01

The relationship of the gastrointestinal microbiome to health and disease is of major research interest, including the effects of the gut microbiota on age related conditions. Here we report on the outcome of a project to collect stool samples on a large number of community dwelling elderly men using the OMNIgene-GUT stool/feces collection kit (OMR-200, DNA Genotek, Ottawa, Canada). Among 1,328 men who were eligible for stool collection, 982 (74%) agreed to participate and 951 submitted samples. The collection process was reported to be acceptable, almost all samples obtained were adequate, the process of sample handling by mail was uniformly successful. The DNA obtained provided excellent results in microbiome analyses, yielding an abundance of species and a diversity of taxa as would be predicted. Our results suggest that population studies of older participants involving remote stool sample collection are feasible. These approaches would allow large scale research projects of the association of the gut microbiota with important clinical outcomes.

Design and Field Procedures in the US National Comorbidity Survey Replication Adolescent Supplement (NCS-A)

PubMed Central

Kessler, Ronald C.; Avenevoli, Shelli; Costello, E. Jane; Green, Jennifer Greif; Gruber, Michael J.; Heeringa, Steven; Merikangas, Kathleen R.; Pennell, Beth-Ellen; Sampson, Nancy A.; Zaslavsky, Alan M.

2009-01-01

An overview is presented of the design and field procedures of the US National Comorbidity Survey Replication Adolescent Supplement (NCS-A), a US face-to-face household survey of the prevalence and correlates of DSM-IV mental disorders. The survey was based on a dual-frame design that included 904 adolescent residents of the households that participated in the US National Comorbidity Survey Replication (85.9% response rate) and 9,244 adolescent students selected from a nationally representative sample of 320 schools (74.7% response rate). After expositing the logic of dual-frame designs, comparisons are presented of sample and population distributions on Census socio-demographic variables and, in the school sample, school characteristics. These document only minor differences between the samples and the population. The results of statistical analysis of the bias-efficiency trade-off in weight trimming are then presented. These show that modest trimming meaningfully reduces mean squared error. Analysis of comparative sample efficiency shows that the household sample is more efficient than the school sample, leading to the household sample getting a higher weight relative to its size in the consolidated sample relative to the school sample. Taken together, these results show that the NCS-A is an efficient sample of the target population with good representativeness on a range of socio-demographic and geographic variables. PMID:19507169

Small-mammal density estimation: A field comparison of grid-based vs. web-based density estimators

USGS Publications Warehouse

Parmenter, R.R.; Yates, Terry L.; Anderson, D.R.; Burnham, K.P.; Dunnum, J.L.; Franklin, A.B.; Friggens, M.T.; Lubow, B.C.; Miller, M.; Olson, G.S.; Parmenter, Cheryl A.; Pollard, J.; Rexstad, E.; Shenk, T.M.; Stanley, T.R.; White, Gary C.

2003-01-01

Statistical models for estimating absolute densities of field populations of animals have been widely used over the last century in both scientific studies and wildlife management programs. To date, two general classes of density estimation models have been developed: models that use data sets from capture–recapture or removal sampling techniques (often derived from trapping grids) from which separate estimates of population size (NÌ‚) and effective sampling area (AÌ‚) are used to calculate density (DÌ‚ = NÌ‚/AÌ‚); and models applicable to sampling regimes using distance-sampling theory (typically transect lines or trapping webs) to estimate detection functions and densities directly from the distance data. However, few studies have evaluated these respective models for accuracy, precision, and bias on known field populations, and no studies have been conducted that compare the two approaches under controlled field conditions. In this study, we evaluated both classes of density estimators on known densities of enclosed rodent populations. Test data sets (n = 11) were developed using nine rodent species from capture–recapture live-trapping on both trapping grids and trapping webs in four replicate 4.2-ha enclosures on the Sevilleta National Wildlife Refuge in central New Mexico, USA. Additional “saturation” trapping efforts resulted in an enumeration of the rodent populations in each enclosure, allowing the computation of true densities. Density estimates (DÌ‚) were calculated using program CAPTURE for the grid data sets and program DISTANCE for the web data sets, and these results were compared to the known true densities (D) to evaluate each model's relative mean square error, accuracy, precision, and bias. In addition, we evaluated a variety of approaches to each data set's analysis by having a group of independent expert analysts calculate their best density estimates without a priori knowledge of the true densities; this “blind” test allowed us to evaluate the influence of expertise and experience in calculating density estimates in comparison to simply using default values in programs CAPTURE and DISTANCE. While the rodent sample sizes were considerably smaller than the recommended minimum for good model results, we found that several models performed well empirically, including the web-based uniform and half-normal models in program DISTANCE, and the grid-based models Mb and Mbh in program CAPTURE (with AÌ‚ adjusted by species-specific full mean maximum distance moved (MMDM) values). These models produced accurate DÌ‚ values (with 95% confidence intervals that included the true D values) and exhibited acceptable bias but poor precision. However, in linear regression analyses comparing each model's DÌ‚ values to the true D values over the range of observed test densities, only the web-based uniform model exhibited a regression slope near 1.0; all other models showed substantial slope deviations, indicating biased estimates at higher or lower density values. In addition, the grid-based DÌ‚ analyses using full MMDM values for WÌ‚ area adjustments required a number of theoretical assumptions of uncertain validity, and we therefore viewed their empirical successes with caution. Finally, density estimates from the independent analysts were highly variable, but estimates from web-based approaches had smaller mean square errors and better achieved confidence-interval coverage of D than did grid-based approaches. Our results support the contention that web-based approaches for density estimation of small-mammal populations are both theoretically and empirically superior to grid-based approaches, even when sample size is far less than often recommended. In view of the increasing need for standardized environmental measures for comparisons among ecosystems and through time, analytical models based on distance sampling appear to offer accurate density estimation approaches for research studies involving small-mammal abundances.

What is a species? A new universal method to measure differentiation and assess the taxonomic rank of allopatric populations, using continuous variables

PubMed Central

Donegan, Thomas M.

2018-01-01

Abstract Existing models for assigning species, subspecies, or no taxonomic rank to populations which are geographically separated from one another were analyzed. This was done by subjecting over 3,000 pairwise comparisons of vocal or biometric data based on birds to a variety of statistical tests that have been proposed as measures of differentiation. One current model which aims to test diagnosability (Isler et al. 1998) is highly conservative, applying a hard cut-off, which excludes from consideration differentiation below diagnosis. It also includes non-overlap as a requirement, a measure which penalizes increases to sample size. The “species scoring” model of Tobias et al. (2010) involves less drastic cut-offs, but unlike Isler et al. (1998), does not control adequately for sample size and attributes scores in many cases to differentiation which is not statistically significant. Four different models of assessing effect sizes were analyzed: using both pooled and unpooled standard deviations and controlling for sample size using t-distributions or omitting to do so. Pooled standard deviations produced more conservative effect sizes when uncontrolled for sample size but less conservative effect sizes when so controlled. Pooled models require assumptions to be made that are typically elusive or unsupported for taxonomic studies. Modifications to improving these frameworks are proposed, including: (i) introducing statistical significance as a gateway to attributing any weighting to findings of differentiation; (ii) abandoning non-overlap as a test; (iii) recalibrating Tobias et al. (2010) scores based on effect sizes controlled for sample size using t-distributions. A new universal method is proposed for measuring differentiation in taxonomy using continuous variables and a formula is proposed for ranking allopatric populations. This is based first on calculating effect sizes using unpooled standard deviations, controlled for sample size using t-distributions, for a series of different variables. All non-significant results are excluded by scoring them as zero. Distance between any two populations is calculated using Euclidian summation of non-zeroed effect size scores. If the score of an allopatric pair exceeds that of a related sympatric pair, then the allopatric population can be ranked as species and, if not, then at most subspecies rank should be assigned. A spreadsheet has been programmed and is being made available which allows this and other tests of differentiation and rank studied in this paper to be rapidly analyzed. PMID:29780266

Oral Microbiota of Children in a School-based Dental Clinic

PubMed Central

Soncini, Jennifer A; Kanasi, Eleni; Lu, Shulin C.; Nunn, Martha E.; Henshaw, Michelle M; Tanner, Anne CR

2010-01-01

Objectives Dental caries disproportionately affects disadvantaged subjects. This study hypothesized that there were greater caries extent and higher levels of caries-associated and anaerobic subgingival bacterial species in oral samples of Hispanic and immigrant children compared with non-Hispanic and US born children. Methods Children from a school-based dental clinic serving a community with a large Hispanic component were examined, and the extent of caries was recorded. Microbial samples were taken from teeth and the tongues of children. Samples were analyzed using DNA probes to 18 oral bacterial species. Results Seventy five children were examined. Extent of caries increased with child age in immigrant, but not in US born or Hispanic children. There were no differences in the microbiota based on ethnicity or whether the child was born in US or not. There was a higher species detection frequency from teeth than tongue samples. Levels of Streptococcus mutans and other Streptococcus species increased with caries extent. Prevotella intermedia, Tannerella forsythia and Selenomonas species were detected at low levels in these children. Conclusions We conclude that, while there was a high rate of dental caries in disadvantaged school children, there were no differences in the caries-associated microbiota, including S. mutans, based on ethnicity or immigration status. Furthermore, while anaerobic subgingival, periodontal pathogens were also detected in children, there was no difference in species detection based on ethnicity or immigration status. Increased levels of streptococci, including S. mutans, however, were detected with high caries levels. This suggested that while it is beneficial to target preventive and treatment programs to disadvantaged populations, there is likely no additional benefit to focus on subgroups within a population already at high risk for dental disease. PMID:19879369

Oral microbiota of children in a school-based dental clinic.

PubMed

Soncini, Jennifer A; Kanasi, Eleni; Lu, Shulin C; Nunn, Martha E; Henshaw, Michelle M; Tanner, Anne C R

2010-06-01

Dental caries disproportionately affects disadvantaged subjects. This study hypothesized that there were greater caries extent and higher levels of caries-associated and anaerobic subgingival bacterial species in oral samples of Hispanic and immigrant children compared with non-Hispanic and US born children. Children from a school-based dental clinic serving a community with a large Hispanic component were examined, and the extent of caries was recorded. Microbial samples were taken from teeth and the tongues of children. Samples were analyzed using DNA probes to 18 oral bacterial species. Seventy five children were examined. Extent of caries increased with child age in immigrant, but not in US born or Hispanic children. There were no differences in the microbiota based on ethnicity or whether the child was born in US or not. There was a higher species detection frequency from teeth than tongue samples. Levels of Streptococcus mutans and other Streptococcus spp increased with caries extent. Prevotella intermedia, Tannerella forsythia and Selenomonas spp were detected at low levels in these children. We conclude that, while there was a high rate of dental caries in disadvantaged school children, there were no differences in the caries-associated microbiota, including S. mutans, based on ethnicity or immigration status. Furthermore, while anaerobic subgingival, periodontal pathogens were also detected in children, there was no difference in species detection based on ethnicity or immigration status. Increased levels of streptococci, including S. mutans, however, were detected with high caries levels. This suggested that while it is beneficial to target preventive and treatment programs to disadvantaged populations, there is likely no additional benefit to focus on subgroups within a population already at high risk for dental disease. 2009 Elsevier Ltd. All rights reserved.

USING A COMMERCIAL TELEPHONE DIRECTORY TO IDENTIFY A POPULATION-BASED SAMPLE OF WOMEN OF REPRODUCTIVE AGE

EPA Science Inventory

Using a commercial telephone directory to identify a population-based sample of women of reproductive age
*DT Lobdell, GM Buck, JM Weiner, P Mendola (United States Environmental Protection Agency, Research Triangle Park, NC 27711)

In the United States, sampling women o...

Invited commentary: recruiting for epidemiologic studies using social media.

PubMed

Allsworth, Jenifer E

2015-05-15

Social media-based recruitment for epidemiologic studies has the potential to expand the demographic and geographic reach of investigators and identify potential participants more cost-effectively than traditional approaches. In fact, social media are particularly appealing for their ability to engage traditionally "hard-to-reach" populations, including young adults and low-income populations. Despite their great promise as a tool for epidemiologists, social media-based recruitment approaches do not currently compare favorably with gold-standard probability-based sampling approaches. Sparse data on the demographic characteristics of social media users, patterns of social media use, and appropriate sampling frames limit our ability to implement probability-based sampling strategies. In a well-conducted study, Harris et al. (Am J Epidemiol. 2015;181(10):737-746) examined the cost-effectiveness of social media-based recruitment (advertisements and promotion) in the Contraceptive Use, Pregnancy Intention, and Decisions (CUPID) Study, a cohort study of 3,799 young adult Australian women, and the approximate representativeness of the CUPID cohort. Implications for social media-based recruitment strategies for cohort assembly, data accuracy, implementation, and human subjects concerns are discussed. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Three Decades of Farmed Escapees in the Wild: A Spatio-Temporal Analysis of Atlantic Salmon Population Genetic Structure throughout Norway

PubMed Central

Glover, Kevin A.; Quintela, María; Wennevik, Vidar; Besnier, François; Sørvik, Anne G. E.; Skaala, Øystein

2012-01-01

Each year, hundreds of thousands of domesticated farmed Atlantic salmon escape into the wild. In Norway, which is the world’s largest commercial producer, many native Atlantic salmon populations have experienced large numbers of escapees on the spawning grounds for the past 15–30 years. In order to study the potential genetic impact, we conducted a spatio-temporal analysis of 3049 fish from 21 populations throughout Norway, sampled in the period 1970–2010. Based upon the analysis of 22 microsatellites, individual admixture, FST and increased allelic richness revealed temporal genetic changes in six of the populations. These changes were highly significant in four of them. For example, 76% and 100% of the fish comprising the contemporary samples for the rivers Vosso and Opo were excluded from their respective historical samples at P = 0.001. Based upon several genetic parameters, including simulations, genetic drift was excluded as the primary cause of the observed genetic changes. In the remaining 15 populations, some of which had also been exposed to high numbers of escapees, clear genetic changes were not detected. Significant population genetic structuring was observed among the 21 populations in the historical (global FST = 0.038) and contemporary data sets (global FST = 0.030), although significantly reduced with time (P = 0.008). This reduction was especially distinct when looking at the six populations displaying temporal changes (global FST dropped from 0.058 to 0.039, P = 0.006). We draw two main conclusions: 1. The majority of the historical population genetic structure throughout Norway still appears to be retained, suggesting a low to modest overall success of farmed escapees in the wild; 2. Genetic introgression of farmed escapees in native salmon populations has been strongly population-dependent, and it appears to be linked with the density of the native population. PMID:22916215

A land manager's guide to point counts of birds in the Southeast

USGS Publications Warehouse

Hamel, P.B.; Smith, W.P.; Twedt, D.J.; Woehr, J.R.; Morris, E.; Hamilton, R.B.; Cooper, R.J.

1996-01-01

Current widespread concern for the status of neotropical migratory birds has sparked interest in techniques for inventorying and monitoring populations of these and other birds in southeastern forest habitats. The present guide gives detailed instructions for conducting point counts of birds. It further presents a detailed methodology for the design and conduct of inventorial and monitoring surveys based on point counts, including discussion of sample size determination, distribution of counts among habitats, cooperation among neighboring land managers, vegetation sampling, standard data format, and other topics. Appendices provide additional information, making this guide a stand-alone text for managers interested in developing inventories of bird populations on their lands.

Methodological Challenges in Collecting Social and Behavioural Data Regarding the HIV Epidemic among Gay and Other Men Who Have Sex with Men in Australia

PubMed Central

Holt, Martin; de Wit, John; Brown, Graham; Maycock, Bruce; Fairley, Christopher; Prestage, Garrett

2014-01-01

Background Behavioural surveillance and research among gay and other men who have sex with men (GMSM) commonly relies on non-random recruitment approaches. Methodological challenges limit their ability to accurately represent the population of adult GMSM. We compared the social and behavioural profiles of GMSM recruited via venue-based, online, and respondent-driven sampling (RDS) and discussed their utility for behavioural surveillance. Methods Data from four studies were selected to reflect each recruitment method. We compared demographic characteristics and the prevalence of key indicators including sexual and HIV testing practices obtained from samples recruited through different methods, and population estimates from respondent-driven sampling partition analysis. Results Overall, the socio-demographic profile of GMSM was similar across samples, with some differences observed in age and sexual identification. Men recruited through time-location sampling appeared more connected to the gay community, reported a greater number of sexual partners, but engaged in less unprotected anal intercourse with regular (UAIR) or casual partners (UAIC). The RDS sample overestimated the proportion of HIV-positive men and appeared to recruit men with an overall higher number of sexual partners. A single-website survey recruited a sample with characteristics which differed considerably from the population estimates with regards to age, ethnically diversity and behaviour. Data acquired through time-location sampling underestimated the rates of UAIR and UAIC, while RDS and online sampling both generated samples that underestimated UAIR. Simulated composite samples combining recruits from time-location and multi-website online sampling may produce characteristics more consistent with the population estimates, particularly with regards to sexual practices. Conclusion Respondent-driven sampling produced the sample that was most consistent to population estimates, but this methodology is complex and logistically demanding. Time-location and online recruitment are more cost-effective and easier to implement; using these approaches in combination may offer the potential to recruit a more representative sample of GMSM. PMID:25409440

Methodological challenges in collecting social and behavioural data regarding the HIV epidemic among gay and other men who have sex with men in Australia.

PubMed

Zablotska, Iryna B; Frankland, Andrew; Holt, Martin; de Wit, John; Brown, Graham; Maycock, Bruce; Fairley, Christopher; Prestage, Garrett

2014-01-01

Behavioural surveillance and research among gay and other men who have sex with men (GMSM) commonly relies on non-random recruitment approaches. Methodological challenges limit their ability to accurately represent the population of adult GMSM. We compared the social and behavioural profiles of GMSM recruited via venue-based, online, and respondent-driven sampling (RDS) and discussed their utility for behavioural surveillance. Data from four studies were selected to reflect each recruitment method. We compared demographic characteristics and the prevalence of key indicators including sexual and HIV testing practices obtained from samples recruited through different methods, and population estimates from respondent-driven sampling partition analysis. Overall, the socio-demographic profile of GMSM was similar across samples, with some differences observed in age and sexual identification. Men recruited through time-location sampling appeared more connected to the gay community, reported a greater number of sexual partners, but engaged in less unprotected anal intercourse with regular (UAIR) or casual partners (UAIC). The RDS sample overestimated the proportion of HIV-positive men and appeared to recruit men with an overall higher number of sexual partners. A single-website survey recruited a sample with characteristics which differed considerably from the population estimates with regards to age, ethnically diversity and behaviour. Data acquired through time-location sampling underestimated the rates of UAIR and UAIC, while RDS and online sampling both generated samples that underestimated UAIR. Simulated composite samples combining recruits from time-location and multi-website online sampling may produce characteristics more consistent with the population estimates, particularly with regards to sexual practices. Respondent-driven sampling produced the sample that was most consistent to population estimates, but this methodology is complex and logistically demanding. Time-location and online recruitment are more cost-effective and easier to implement; using these approaches in combination may offer the potential to recruit a more representative sample of GMSM.

Molecular diagnosis of strongyloidiasis in a population of an endemic area through nested-PCR.

PubMed

Sharifdini, Meysam; Keyhani, Amir; Eshraghian, Mohammad Reza; Beigom Kia, Eshrat

2018-01-01

This study is aimed to diagnose and analyze strongyloidiasis in a population of an endemic area of Iran using nested-PCR, coupled with parasitological methods. Screening of strongyloidiasis infected people using reliable diagnostic techniques are essential to decrease the mortality and morbidity associated with this infection. Molecular methods have been proved to be highly sensitive and specific for detection of Strongyloides stercoralis in stool samples. A total of 155 fresh single stool samples were randomly collected from residents of north and northwest of Khouzestan Province, Iran. All samples were examined by parasitological methods including formalin-ether concentration and nutrient agar plate culture, and molecular method of nested-PCR. Infections with S. stercoralis were analyzed according to demographic criteria. Based on the results of nested-PCR method 15 cases (9.7%) were strongyloidiasis positive. Nested-PCR was more sensitive than parasitological techniques on single stool sampling. Elderly was the most important population index for higher infectivity with S. stercoralis . In endemic areas of S. stercoralis , old age should be considered as one of the most important risk factors of infection, especially among the immunosuppressed individuals.

Respondent-driven sampling for an adolescent health study in vulnerable urban settings: a multi-country study.

PubMed

Decker, Michele R; Marshall, Beth Dail; Emerson, Mark; Kalamar, Amanda; Covarrubias, Laura; Astone, Nan; Wang, Ziliang; Gao, Ersheng; Mashimbye, Lawrence; Delany-Moretlwe, Sinead; Acharya, Rajib; Olumide, Adesola; Ojengbede, Oladosu; Blum, Robert W; Sonenstein, Freya L

2014-12-01

The global adolescent population is larger than ever before and is rapidly urbanizing. Global surveillance systems to monitor youth health typically use household- and school-based recruitment methods. These systems risk not reaching the most marginalized youth made vulnerable by conditions of migration, civil conflict, and other forms of individual and structural vulnerability. We describe the methodology of the Well-Being of Adolescents in Vulnerable Environments survey, which used respondent-driven sampling (RDS) to recruit male and female youth aged 15-19 years and living in economically distressed urban settings in Baltimore, MD; Johannesburg, South Africa; Ibadan, Nigeria; New Delhi, India; and Shanghai, China (migrant youth only) for a cross-sectional study. We describe a shared recruitment and survey administration protocol across the five sites, present recruitment parameters, and illustrate challenges and necessary adaptations for use of RDS with youth in disadvantaged urban settings. We describe the reach of RDS into populations of youth who may be missed by traditional household- and school-based sampling. Across all sites, an estimated 9.6% were unstably housed; among those enrolled in school, absenteeism was pervasive with 29% having missed over 6 days of school in the past month. Overall findings confirm the feasibility, efficiency, and utility of RDS in quickly reaching diverse samples of youth, including those both in and out of school and those unstably housed, and provide direction for optimizing RDS methods with this population. In our rapidly urbanizing global landscape with an unprecedented youth population, RDS may serve as a valuable tool in complementing existing household- and school-based methods for health-related surveillance that can guide policy. Copyright © 2014 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Respondent-driven sampling for an adolescent health study in vulnerable urban settings: a multi-country study

PubMed Central

Decker, Michele R.; Marshall, Beth; Emerson, Mark; Kalamar, Amanda; Covarrubias, Laura; Astone, Nan; Wang, Ziliang; Gao, Ersheng; Mashimbye, Lawrence; Delany-Moretlwe, Sinead; Acharya, Rajib; Olumide, Adesola; Ojengbede, Oladosu; Blum, Robert

2015-01-01

The global adolescent population is larger than ever before and is rapidly urbanizing. Global surveillance systems to monitor youth health typically use household- and school-based recruitment methods. These systems risk not reaching the most marginalized youth made vulnerable by conditions of migration, civil conflict and other forms of individual and structural vulnerability. We describe the methodology of the Well Being of Adolescents in Vulnerable Environments (WAVE) survey, which used respondent-driven sampling (RDS) to recruit male and female youth aged 15 to 19 years and living in economically distressed urban settings in Baltimore, USA, Johannesburg, South Africa, Ibadan, Nigeria, Delhi, India and Shanghai, China (migrant youth only) for a cross-sectional study. We describe a shared recruitment and survey administration protocol across the five sites, present recruitment parameters, and illustrate challenges and necessary adaptations for use of RDS with youth in disadvantaged urban settings. We describe the reach of RDS into populations of youth who may be missed by traditional householdbased and school-based sampling. Across all sites, an estimated 9.6% were unstably housed; among those enrolled in school, absenteeism was pervasive with 29% having missed over 6 days of school in the past month. Overall findings confirm the feasibility, efficiency and utility of RDS in quickly reaching diverse samples of youth, including those both in and out of school and those unstably housed, and provide direction for optimizing RDS methods with this population. In our rapidly urbanizing global landscape with an unprecedented youth population, RDS may serve as a valuable tool in complementing existing household- and school-based methods for health-related surveillance that can guide policy. PMID:25454005

Orthopedic implant devices: prevalence and sociodemographic findings from the 1988 National Health Interview Survey.

PubMed

Moore, R M; Hamburger, S; Jeng, L L; Hamilton, P M

1991-01-01

National population-based estimates on the magnitude and distribution of orthopedic implant devices in the United States have not been available to date. The Food and Drug Administration's Center for Devices and Radiological Health (FDA/CDRH) collaborated with the Centers for Disease Control's National Center for Health Statistics (CDC/NCHS) in the design and conduct of a nationwide medical device implant survey to generate the first national population-based prevalence estimates of orthopedic implant devices. A Medical Device Implant Supplement to the 1988 National Health Interview Survey was administered in personal household interviews to a national sample of 47,485 households, which included 122,310 individuals. An estimated 6.5 million orthopedic implants were in use in the general US population in 1988, including 1.6 million artificial joints and 4.9 million fixation devices. As a group, orthopedic implants comprised nearly half of all medical device implants in use, 43.4%. The majority of artificial joint recipients were 65 years of age or older, white, and male. The majority of fixation device recipients were less than 45 years of age, white, and male. The limitations and strengths of these population-based estimates are discussed.

The Impact of Selection, Gene Conversion, and Biased Sampling on the Assessment of Microbial Demography.

PubMed

Lapierre, Marguerite; Blin, Camille; Lambert, Amaury; Achaz, Guillaume; Rocha, Eduardo P C

2016-07-01

Recent studies have linked demographic changes and epidemiological patterns in bacterial populations using coalescent-based approaches. We identified 26 studies using skyline plots and found that 21 inferred overall population expansion. This surprising result led us to analyze the impact of natural selection, recombination (gene conversion), and sampling biases on demographic inference using skyline plots and site frequency spectra (SFS). Forward simulations based on biologically relevant parameters from Escherichia coli populations showed that theoretical arguments on the detrimental impact of recombination and especially natural selection on the reconstructed genealogies cannot be ignored in practice. In fact, both processes systematically lead to spurious interpretations of population expansion in skyline plots (and in SFS for selection). Weak purifying selection, and especially positive selection, had important effects on skyline plots, showing patterns akin to those of population expansions. State-of-the-art techniques to remove recombination further amplified these biases. We simulated three common sampling biases in microbiological research: uniform, clustered, and mixed sampling. Alone, or together with recombination and selection, they further mislead demographic inferences producing almost any possible skyline shape or SFS. Interestingly, sampling sub-populations also affected skyline plots and SFS, because the coalescent rates of populations and their sub-populations had different distributions. This study suggests that extreme caution is needed to infer demographic changes solely based on reconstructed genealogies. We suggest that the development of novel sampling strategies and the joint analyzes of diverse population genetic methods are strictly necessary to estimate demographic changes in populations where selection, recombination, and biased sampling are present. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Geospatial techniques for developing a sampling frame of watersheds across a region

USGS Publications Warehouse

Gresswell, Robert E.; Bateman, Douglas S.; Lienkaemper, George; Guy, T.J.

2004-01-01

Current land-management decisions that affect the persistence of native salmonids are often influenced by studies of individual sites that are selected based on judgment and convenience. Although this approach is useful for some purposes, extrapolating results to areas that were not sampled is statistically inappropriate because the sampling design is usually biased. Therefore, in recent investigations of coastal cutthroat trout (Oncorhynchus clarki clarki) located above natural barriers to anadromous salmonids, we used a methodology for extending the statistical scope of inference. The purpose of this paper is to apply geospatial tools to identify a population of watersheds and develop a probability-based sampling design for coastal cutthroat trout in western Oregon, USA. The population of mid-size watersheds (500-5800 ha) west of the Cascade Range divide was derived from watershed delineations based on digital elevation models. Because a database with locations of isolated populations of coastal cutthroat trout did not exist, a sampling frame of isolated watersheds containing cutthroat trout had to be developed. After the sampling frame of watersheds was established, isolated watersheds with coastal cutthroat trout were stratified by ecoregion and erosion potential based on dominant bedrock lithology (i.e., sedimentary and igneous). A stratified random sample of 60 watersheds was selected with proportional allocation in each stratum. By comparing watershed drainage areas of streams in the general population to those in the sampling frame and the resulting sample (n = 60), we were able to evaluate the how representative the subset of watersheds was in relation to the population of watersheds. Geospatial tools provided a relatively inexpensive means to generate the information necessary to develop a statistically robust, probability-based sampling design.

Temporal fluctuation in North East Baltic Sea region cattle population revealed by mitochondrial and Y-chromosomal DNA analyses.

PubMed

Niemi, Marianna; Bläuer, Auli; Iso-Touru, Terhi; Harjula, Janne; Nyström Edmark, Veronica; Rannamäe, Eve; Lõugas, Lembi; Sajantila, Antti; Lidén, Kerstin; Taavitsainen, Jussi-Pekka

2015-01-01

Ancient DNA analysis offers a way to detect changes in populations over time. To date, most studies of ancient cattle have focused on their domestication in prehistory, while only a limited number of studies have analysed later periods. Conversely, the genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies. Bones and teeth from ancient cattle populations from the North-East Baltic Sea region dated to the Prehistoric (Late Bronze and Iron Age, 5 samples), Medieval (14), and Post-Medieval (26) periods were investigated by sequencing 667 base pairs (bp) from the mitochondrial DNA (mtDNA) and 155 bp of intron 19 in the Y-chromosomal UTY gene. Comparison of maternal (mtDNA haplotypes) genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mtDNA haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples. Of seven Y-chromosomal sequences determined from ancient samples, six were Y2 and one Y1 haplotype. Combined data including Swedish samples from the same periods (64 samples) was compared with the occurrence of Y-chromosomal haplotypes in modern cattle (1614 samples). The diversity of haplogroups was highest in the Prehistoric samples, where many haplotypes were unique. The Medieval and Post-Medieval samples also show a high diversity with new haplotypes. Some of these haplotypes have become frequent in modern breeds in the Nordic Countries and North-Western Russia while other haplotypes have remained in only a few local breeds or seem to have been lost. A temporal shift in Y-chromosomal haplotypes from Y2 to Y1 was detected that corresponds with the appearance of new mtDNA haplotypes in the Medieval and Post-Medieval period. This suggests a replacement of the Prehistoric mtDNA and Y chromosomal haplotypes by new types of cattle.

Temporal Fluctuation in North East Baltic Sea Region Cattle Population Revealed by Mitochondrial and Y-Chromosomal DNA Analyses

PubMed Central

Niemi, Marianna; Bläuer, Auli; Iso-Touru, Terhi; Harjula, Janne; Nyström Edmark, Veronica; Rannamäe, Eve; Lõugas, Lembi; Sajantila, Antti; Lidén, Kerstin; Taavitsainen, Jussi-Pekka

2015-01-01

Background Ancient DNA analysis offers a way to detect changes in populations over time. To date, most studies of ancient cattle have focused on their domestication in prehistory, while only a limited number of studies have analysed later periods. Conversely, the genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies. Results Bones and teeth from ancient cattle populations from the North-East Baltic Sea region dated to the Prehistoric (Late Bronze and Iron Age, 5 samples), Medieval (14), and Post-Medieval (26) periods were investigated by sequencing 667 base pairs (bp) from the mitochondrial DNA (mtDNA) and 155 bp of intron 19 in the Y-chromosomal UTY gene. Comparison of maternal (mtDNA haplotypes) genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mtDNA haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples. Of seven Y-chromosomal sequences determined from ancient samples, six were Y2 and one Y1 haplotype. Combined data including Swedish samples from the same periods (64 samples) was compared with the occurrence of Y-chromosomal haplotypes in modern cattle (1614 samples). Conclusions The diversity of haplogroups was highest in the Prehistoric samples, where many haplotypes were unique. The Medieval and Post-Medieval samples also show a high diversity with new haplotypes. Some of these haplotypes have become frequent in modern breeds in the Nordic Countries and North-Western Russia while other haplotypes have remained in only a few local breeds or seem to have been lost. A temporal shift in Y-chromosomal haplotypes from Y2 to Y1 was detected that corresponds with the appearance of new mtDNA haplotypes in the Medieval and Post-Medieval period. This suggests a replacement of the Prehistoric mtDNA and Y chromosomal haplotypes by new types of cattle. PMID:25992976

U.S. consumer demand for restaurant calorie information: targeting demographic and behavioral segments in labeling initiatives.

PubMed

Kolodinsky, Jane; Reynolds, Travis William; Cannella, Mark; Timmons, David; Bromberg, Daniel

2009-01-01

To identify different segments of U.S. consumers based on food choices, exercise patterns, and desire for restaurant calorie labeling. Using a stratified (by region) random sample of the U.S. population, trained interviewers collected data for this cross-sectional study through telephone surveys. Center for Rural Studies U.S. national health survey. The final sample included 580 responses (22% response rate); data were weighted to be representative of age and gender characteristics of the U.S. population. Self-reported behaviors related to food choices, exercise patterns, desire for calorie information in restaurants, and sample demographics. Clusters were identified using Schwartz Bayesian criteria. Impacts of demographic characteristics on cluster membership were analyzed using bivariate tests of association and multinomial logit regression. Cluster analysis revealed three clusters based on respondents' food choices, activity levels, and desire for restaurant labeling. Two clusters, comprising three quarters of the sample, desired calorie labeling in restaurants. The remaining cluster opposed restaurant labeling. Demographic variables significantly predicting cluster membership included region of residence (p < .10), income (p < .05), gender (p < .01), and age (p < .10). Though limited by a low response and potential self-reporting bias in the phone survey, this study suggests that several groups are likely to benefit from restaurant calorie labeling. Specific demographic clusters could be targeted through labeling initiatives.

The Queensland study of Melanoma: Environmental and Genetic Associations (Q-MEGA). Study design, baseline characteristics, and repeatability of phenotype and sun exposure measures

PubMed Central

Baxter, Amanda J.; Hughes, Maria Celia; Kvaskoff, Marina; Siskind, Victor; Shekar, Sri; Aitken, Joanne F.; Green, Adele C.; Duffy, David L.; Hayward, Nicholas K.; Martin, Nicholas G.; Whiteman, David C.

2013-01-01

Cutaneous malignant melanoma (CMM) is a major health issue in Queensland, Australia which has the world’s highest incidence. Recent molecular and epidemiologic studies suggest that CMM arises through multiple etiological pathways involving gene-environment interactions. Understanding the potential mechanisms leading to CMM requires larger studies than those previously conducted. This article describes the design and baseline characteristics of Q-MEGA, the Queensland study of Melanoma: Environmental and Genetic Associations, which followed-up four population-based samples of CMM patients in Queensland, including children, adolescents, men aged over 50, and a large sample of adult cases and their families, including twins. Q-MEGA aims to investigate the roles of genetic and environmental factors, and their interaction, in the etiology of melanoma. 3,471 participants took part in the follow-up study and were administered a computer-assisted telephone interview in 2002–2005. Updated data on environmental and phenotypic risk factors, and 2,777 blood samples were collected from interviewed participants as well as a subset of relatives. This study provides a large and well-described population-based sample of CMM cases with follow-up data. Characteristics of the cases and repeatability of sun exposure and phenotype measures between the baseline and the follow-up surveys, from six to 17 years later, are also described. PMID:18361720

Simulated fissioning of uranium and testing of the fission-track dating method

USGS Publications Warehouse

McGee, V.E.; Johnson, N.M.; Naeser, C.W.

1985-01-01

A computer program (FTD-SIM) faithfully simulates the fissioning of 238U with time and 235U with neutron dose. The simulation is based on first principles of physics where the fissioning of 238U with the flux of time is described by Ns = ??f 238Ut and the fissioning of 235U with the fluence of neutrons is described by Ni = ??235U??. The Poisson law is used to set the stochastic variation of fissioning within the uranium population. The life history of a given crystal can thus be traced under an infinite variety of age and irradiation conditions. A single dating attempt or up to 500 dating attempts on a given crystal population can be simulated by specifying the age of the crystal population, the size and variation in the areas to be counted, the amount and distribution of uranium, the neutron dose to be used and its variation, and the desired ratio of 238U to 235U. A variety of probability distributions can be applied to uranium and counting-area. The Price and Walker age equation is used to estimate age. The output of FTD-SIM includes the tabulated results of each individual dating attempt (sample) on demand and/or the summary statistics and histograms for multiple dating attempts (samples) including the sampling age. An analysis of the results from FTD-SIM shows that: (1) The external detector method is intrinsically more precise than the population method. (2) For the external detector method a correlation between spontaneous track count, Ns, and induced track count, Ni, results when the population of grains has a stochastic uranium content and/or when the counting areas between grains are stochastic. For the population method no correlation can exist. (3) In the external detector method the sampling distribution of age is independent of the number of grains counted. In the population method the sampling distribution of age is highly dependent on the number of grains counted. (4) Grains with zero-track counts, either in Ns or Ni, are in integral part of fissioning theory and under certain circumstances must be included in any estimate of age. (5) In estimating standard error of age the standard error of Ns and Ni and ?? must be accurately estimated and propagated through the age equation. Several statistical models are presently available to do so. ?? 1985.

Prevalence and socioeconomic correlates of chronic morbidity among elderly people in Kosovo: a population-based survey

PubMed Central

2013-01-01

Background Our aim was to assess the prevalence and demographic and socioeconomic correlates of chronic morbidity in the elderly population of transitional Kosovo. Methods A cross-sectional study was conducted in Kosovo in 2011 including a representative sample of 1890 individuals aged ≥65 years (949 men, mean age 73 ± 6 years; 941 women, mean age 74 ± 7 years; response rate: 83%). A structured questionnaire inquired about the presence and the number of self-reported chronic diseases among elderly people, and their access to medical care. Demographic and socioeconomic data were also collected. Binary logistic regression was used to assess the association of demographic and socioeconomic characteristics with chronic conditions. Results In this nationwide population-based sample in Kosovo, 42% of elderly people were unable to access medical care, of whom 88% due to unaffordable costs. About 83% of the elderly people reported at least one chronic condition (63% cardiovascular diseases), and 45% had at least two chronic diseases. In multivariable-adjusted models, factors associated with the presence of chronic conditions and/or multimorbidity were female sex, older age, self-perceived poverty and the inability to access medical care. Conclusion This study provides important evidence on the magnitude and distribution of chronic conditions among the elderly population of Kosovo. Our findings suggest that, in this sample of elderly people from Kosovo, the oldest-old (especially women) and the poor endure the vast majority of chronic conditions. These findings point to the urgent need to establish a social health insurance scheme including the marginalized segments of elderly people in this transitional country. PMID:23452830

Occurence of internet addiction in a general population sample: a latent class analysis.

PubMed

Rumpf, Hans-Jürgen; Vermulst, Ad A; Bischof, Anja; Kastirke, Nadin; Gürtler, Diana; Bischof, Gallus; Meerkerk, Gert-Jan; John, Ulrich; Meyer, Christian

2014-01-01

Prevalence studies of Internet addiction in the general population are rare. In addition, a lack of approved criteria hampers estimation of its occurrence. This study conducted a latent class analysis (LCA) in a large general population sample to estimate prevalence. A telephone survey was conducted based on a random digit dialling procedure including landline telephone (n=14,022) and cell phone numbers (n=1,001) in participants aged 14-64. The Compulsive Internet Use Scale (CIUS) served as the basis for a LCA used to look for subgroups representing participants with Internet addiction or at-risk use. CIUS was given to participants reporting to use the Internet for private purposes at least 1 h on a typical weekday or at least 1 h on a day at the weekend (n=8,130). A 6-class model showed best model fit and included two groups likely to represent Internet addiction and at-risk Internet use. Both groups showed less social participation and the Internet addiction group less general trust in other people. Proportions of probable Internet addiction were 1.0% (CI 0.9-1.2) among the entire sample, 2.4% (CI 1.9-3.1) in the age group 14-24, and 4.0% (CI 2.7-5.7) in the age group 14-16. No difference in estimated proportions between males and females was found. Unemployment (OR 3.13; CI 1.74-5.65) and migration background (OR 3.04; CI 2.12-4.36) were related to Internet addiction. This LCA-based study differentiated groups likely to have Internet addiction and at-risk use in the general population and provides characteristics to further define this rather new disorder. © 2013 S. Karger AG, Basel.

Microbial populations in contaminant plumes

USGS Publications Warehouse

Haack, S.K.; Bekins, B.A.

2000-01-01

Efficient biodegradation of subsurface contaminants requires two elements: (1) microbial populations with the necessary degradative capabilities, and (2) favorable subsurface geochemical and hydrological conditions. Practical constraints on experimental design and interpretation in both the hydrogeological and microbiological sciences have resulted in limited knowledge of the interaction between hydrogeological and microbiological features of subsurface environments. These practical constraints include: (1) inconsistencies between the scales of investigation in the hydrogeological and microbiological sciences, and (2) practical limitations on the ability to accurately define microbial populations in environmental samples. However, advances in application of small-scale sampling methods and interdisciplinary approaches to site investigations are beginning to significantly improve understanding of hydrogeological and microbiological interactions. Likewise, culture-based and molecular analyses of microbial populations in subsurface contaminant plumes have revealed significant adaptation of microbial populations to plume environmental conditions. Results of recent studies suggest that variability in subsurface geochemical and hydrological conditions significantly influences subsurface microbial-community structure. Combined investigations of site conditions and microbial-community structure provide the knowledge needed to understand interactions between subsurface microbial populations, plume geochemistry, and contaminant biodegradation.

Biogeography of bacteriophages at four hydrothermal vent sites in the Antarctic based on g23 sequence diversity.

PubMed

Millard, Andrew D; Pearce, David; Zwirglmaier, Katrin

2016-04-01

In this study, which was carried out within the ChEsSO consortium project (Chemosynthetically driven ecosystems south of the Polar Front), we sampled two hydrothermal vent sites on the East Scotia Ridge, Scotia Sea, one in the Kemp Caldera, South Sandwich Arc and one in the Bransfield Strait, north-west of the Antarctic Peninsula, which exhibit strong differences in their chemical characteristics. We compared a subset of their bacteriophage population by Sanger- and 454-sequencing of g23, which codes for the major capsid protein of T4likeviruses. We found that the sites differ vastly in their bacteriophage diversity, which reflects the differences in the chemical conditions and therefore putatively the differences in microbial hosts living at these sites. Comparing phage diversity in the vent samples to other aquatic samples, the vent samples formed a distinct separate cluster, which also included the non-vent control samples that were taken several hundred meters above the vent chimneys. This indicates that the influence of the vents on the microbial population and therefore also the bacteriophage population extends much further than anticipated. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Polystyrene microspheres enable 10‐color compensation for immunophenotyping of primary human leukocytes

PubMed Central

Carr, Karen D.; Norman, John C.; Huye, Leslie; Hegde, Meenakshi

2015-01-01

Abstract Compensation is a critical process for the unbiased analysis of flow cytometry data. Numerous compensation strategies exist, including the use of bead‐based products. The purpose of this study was to determine whether beads, specifically polystyrene microspheres (PSMS) compare to the use of primary leukocytes for single color based compensation when conducting polychromatic flow cytometry. To do so, we stained individual tubes of both PSMS and leukocytes with panel specific antibodies conjugated to fluorochromes corresponding to fluorescent channels FL1‐FL10. We compared the matrix generated by PSMS to that generated using peripheral blood mononuclear cells (PBMC). Ideal for compensation is a sample with both a discrete negative population and a bright positive population. We demonstrate that PSMS display autofluorescence properties similar to PBMC. When comparing PSMS to PBMC for compensation PSMS yielded more evenly distributed and discrete negative and positive populations to use for compensation. We analyzed three donors' PBMC stained with our 10‐color T cell subpopulation panel using compensation generated by PSMS vs.PBMC and detected no significant differences in the population distribution. Panel specific antibodies bound to PSMS represent an invaluable valid tool to generate suitable compensation matrices especially when sample material is limited and/or the sample requires analysis of dynamically modulated or rare events. © 2015 The Authors. Cytometry Part A Published by Wiley Periodicals, Inc. PMID:26202733

Kinetic quantitation of cerebral PET-FDG studies without concurrent blood sampling: statistical recovery of the arterial input function.

PubMed

O'Sullivan, F; Kirrane, J; Muzi, M; O'Sullivan, J N; Spence, A M; Mankoff, D A; Krohn, K A

2010-03-01

Kinetic quantitation of dynamic positron emission tomography (PET) studies via compartmental modeling usually requires the time-course of the radio-tracer concentration in the arterial blood as an arterial input function (AIF). For human and animal imaging applications, significant practical difficulties are associated with direct arterial sampling and as a result there is substantial interest in alternative methods that require no blood sampling at the time of the study. A fixed population template input function derived from prior experience with directly sampled arterial curves is one possibility. Image-based extraction, including requisite adjustment for spillover and recovery, is another approach. The present work considers a hybrid statistical approach based on a penalty formulation in which the information derived from a priori studies is combined in a Bayesian manner with information contained in the sampled image data in order to obtain an input function estimate. The absolute scaling of the input is achieved by an empirical calibration equation involving the injected dose together with the subject's weight, height and gender. The technique is illustrated in the context of (18)F -Fluorodeoxyglucose (FDG) PET studies in humans. A collection of 79 arterially sampled FDG blood curves are used as a basis for a priori characterization of input function variability, including scaling characteristics. Data from a series of 12 dynamic cerebral FDG PET studies in normal subjects are used to evaluate the performance of the penalty-based AIF estimation technique. The focus of evaluations is on quantitation of FDG kinetics over a set of 10 regional brain structures. As well as the new method, a fixed population template AIF and a direct AIF estimate based on segmentation are also considered. Kinetics analyses resulting from these three AIFs are compared with those resulting from radially sampled AIFs. The proposed penalty-based AIF extraction method is found to achieve significant improvements over the fixed template and the segmentation methods. As well as achieving acceptable kinetic parameter accuracy, the quality of fit of the region of interest (ROI) time-course data based on the extracted AIF, matches results based on arterially sampled AIFs. In comparison, significant deviation in the estimation of FDG flux and degradation in ROI data fit are found with the template and segmentation methods. The proposed AIF extraction method is recommended for practical use.

A population-based study on phobic fears and DSM-IV specific phobia in 70-year olds.

PubMed

Sigström, Robert; Östling, Svante; Karlsson, Björn; Waern, Margda; Gustafson, Deborah; Skoog, Ingmar

2011-01-01

This population-based study reports on the prevalence and characteristics of specific phobia (SP) and phobic fears in an elderly population. A representative population sample of Swedish 70-year-olds without dementia (N = 558) was examined using semi-structured interviews. Phobic fears included fear of animals, natural environment, specific situations, blood-injection-injury and 'other'. Mental disorders, including SP, were diagnosed according to DSM-IV. Phobic fears (71.0% vs. 37.9%) and SP (13.8% vs. 4.5%) were more common in women than in men. Among those with phobic fears, more than 80% reported onset before age 21. Of those with SP, 35.7% had another DSM-IV diagnosis compared to 8.5% of those reporting no fear. Fear of specific situations and 'other' fears were related to SP and other anxiety disorders. SP was related to lower global functioning. We conclude that specific phobia in the elderly should receive attention from health professionals as it is common and associated with a decrease in global functioning. Copyright © 2010 Elsevier Ltd. All rights reserved.

Toward evidence-based interventions for diverse populations: The San Francisco General Hospital prevention and treatment manuals.

PubMed

Muñoz, Ricardo F; Mendelson, Tamar

2005-10-01

Clinical trials have seldom included adequate samples of people of color. Therefore, practitioners serving ethnic minorities often do not have access to readily available evidence-based interventions. This article summarizes the development and empirical evaluation of prevention and treatment manuals designed for low-income ethnic minority populations at San Francisco General Hospital. The manuals were often designed by people of color familiar with the communities for which they were developed. Independent research teams in multi-site national and international clinical trials have evaluated many of these manuals with encouraging results. ((c) 2005 APA, all rights reserved).

Effects of aging on sleep structure throughout adulthood: a population-based study.

PubMed

Moraes, Walter; Piovezan, Ronaldo; Poyares, Dalva; Bittencourt, Lia Rita; Santos-Silva, Rogerio; Tufik, Sergio

2014-04-01

Although many studies have shown the evolution of sleep parameters across the lifespan, not many have included a representative sample of the general population. The objective of this study was to describe age-related changes in sleep structure, sleep respiratory parameters and periodic limb movements of the adult population of São Paulo. We selected a representative sample of the city of São Paulo, Brazil that included both genders and an age range of 20-80 years. Pregnant and lactating women, people with physical or mental impairments that prevent self-care and people who work every night were not included. This sample included 1024 individuals who were submitted to polysomnography and structured interviews. We subdivided our sample into five-year age groups. One-way analysis of variance was used to compare age groups. Pearson product-moment was used to evaluate correlation between age and sleep parameters. Total sleep time, sleep efficiency, percentage of rapid eye movement (REM) sleep and slow wave sleep showed a significant age-related decrease (P<0.05). WASO (night-time spent awake after sleep onset), arousal index, sleep latency, REM sleep latency, and the percentage of stages 1 and 2 showed a significant increase (P<0.05). Furthermore, apnea-hypopnea index increased and oxygen saturation decreased with age. The reduction in the percentage of REM sleep significantly correlated with age in women, whereas the reduction in the percentage of slow wave sleep correlated with age in men. The periodic limb movement (PLM) index increased with age in men and women. Sleep structure and duration underwent significant alterations throughout the aging process in the general population. There was an important correlation between age, sleep respiratory parameters and PLM index. In addition, men and women showed similar trends but with different effect sizes. Copyright © 2014 Elsevier B.V. All rights reserved.

Differential expression analysis for RNAseq using Poisson mixed models

PubMed Central

Sun, Shiquan; Hood, Michelle; Scott, Laura; Peng, Qinke; Mukherjee, Sayan; Tung, Jenny

2017-01-01

Abstract Identifying differentially expressed (DE) genes from RNA sequencing (RNAseq) studies is among the most common analyses in genomics. However, RNAseq DE analysis presents several statistical and computational challenges, including over-dispersed read counts and, in some settings, sample non-independence. Previous count-based methods rely on simple hierarchical Poisson models (e.g. negative binomial) to model independent over-dispersion, but do not account for sample non-independence due to relatedness, population structure and/or hidden confounders. Here, we present a Poisson mixed model with two random effects terms that account for both independent over-dispersion and sample non-independence. We also develop a scalable sampling-based inference algorithm using a latent variable representation of the Poisson distribution. With simulations, we show that our method properly controls for type I error and is generally more powerful than other widely used approaches, except in small samples (n <15) with other unfavorable properties (e.g. small effect sizes). We also apply our method to three real datasets that contain related individuals, population stratification or hidden confounders. Our results show that our method increases power in all three data compared to other approaches, though the power gain is smallest in the smallest sample (n = 6). Our method is implemented in MACAU, freely available at www.xzlab.org/software.html. PMID:28369632

Influence of population versus convenience sampling on sample characteristics in studies of cognitive aging.

PubMed

Brodaty, Henry; Mothakunnel, Annu; de Vel-Palumbo, Melissa; Ames, David; Ellis, Kathryn A; Reppermund, Simone; Kochan, Nicole A; Savage, Greg; Trollor, Julian N; Crawford, John; Sachdev, Perminder S

2014-01-01

We examined whether differences in findings of studies examining mild cognitive impairment (MCI) were associated with recruitment methods by comparing sample characteristics in two contemporaneous Australian studies, using population-based and convenience sampling. The Sydney Memory and Aging Study invited participants randomly from the electoral roll in defined geographic areas in Sydney. The Australian Imaging, Biomarkers and Lifestyle Study of Ageing recruited cognitively normal (CN) individuals via media appeals and MCI participants via referrals from clinicians in Melbourne and Perth. Demographic and cognitive variables were harmonized, and similar diagnostic criteria were applied to both samples retrospectively. CN participants recruited via convenience sampling were younger, better educated, more likely to be married and have a family history of dementia, and performed better cognitively than those recruited via population-based sampling. MCI participants recruited via population-based sampling had better memory performance and were less likely to carry the apolipoprotein E ε4 allele than clinically referred participants but did not differ on other demographic variables. A convenience sample of normal controls is likely to be younger and better functioning and that of an MCI group likely to perform worse than a purportedly random sample. Sampling bias should be considered when interpreting findings. Copyright © 2014 Elsevier Inc. All rights reserved.

Safe Schools? Transgender Youth's School Experiences and Perceptions of School Climate.

PubMed

Day, Jack K; Perez-Brumer, Amaya; Russell, Stephen T

2018-06-01

The magnitude of gender identity-related disparities in school-based outcomes is unknown because of a lack of representative studies that include measures of gender identity. By utilizing a representative sample generalizable to a broader population, this study elucidates the size of gender identity-related disparities, independent of sexual orientation, in school experiences associated with school connectedness and perceptions of school climate. Additionally, the inclusion of and comparison to results of a large non-representative sample allows for more direct comparisons to previous studies of the school experiences of transgender youth. The analyses in this study primarily draw on a sample of 31,896 youth representative of the middle and high school population in California who participated in the 2013-2015 California Student Survey (a subsample of the California Healthy Kids Survey, which includes the largest known sample of transgender youth). Over half the sample identified their sex as female (51.3%), and 398 identified as transgender (1.0%). The sample was racially and ethnically diverse: 30.7% identified as multiracial, 33.0% as White, 11.1% as Asian, 7.4% as Black, and 52.9% as Hispanic. Findings from multilevel analyses show that relative to non-transgender youth, transgender youth were more likely to be truant from school, to experience victimization and bias-based bullying, and to report more negative perceptions of school climate, though did not differ in self-reported grades. The findings have implications for improving school policies and practices to create safer and more supportive school climates for all youth.

Consequences of population topology for studying gene flow using link-based landscape genetic methods.

PubMed

van Strien, Maarten J

2017-07-01

Many landscape genetic studies aim to determine the effect of landscape on gene flow between populations. These studies frequently employ link-based methods that relate pairwise measures of historical gene flow to measures of the landscape and the geographical distance between populations. However, apart from landscape and distance, there is a third important factor that can influence historical gene flow, that is, population topology (i.e., the arrangement of populations throughout a landscape). As the population topology is determined in part by the landscape configuration, I argue that it should play a more prominent role in landscape genetics. Making use of existing literature and theoretical examples, I discuss how population topology can influence results in landscape genetic studies and how it can be taken into account to improve the accuracy of these results. In support of my arguments, I have performed a literature review of landscape genetic studies published during the first half of 2015 as well as several computer simulations of gene flow between populations. First, I argue why one should carefully consider which population pairs should be included in link-based analyses. Second, I discuss several ways in which the population topology can be incorporated in response and explanatory variables. Third, I outline why it is important to sample populations in such a way that a good representation of the population topology is obtained. Fourth, I discuss how statistical testing for link-based approaches could be influenced by the population topology. I conclude the article with six recommendations geared toward better incorporating population topology in link-based landscape genetic studies.

Facebook advertisements recruit parents of children with cancer for an online survey of web-based research preferences.

PubMed

Akard, Terrah Foster; Wray, Sarah; Gilmer, Mary Jo

2015-01-01

Studies involving samples of children with life-threatening illnesses and their families face significant challenges, including inadequate sample sizes and limited diversity. Social media recruitment and Web-based research methods may help address such challenges yet have not been explored in pediatric cancer populations. This study examined the feasibility of using Facebook advertisements to recruit parent caregivers of children and teenagers with cancer. We also explored the feasibility of Web-based video recording in pediatric palliative care populations by surveying parents of children with cancer regarding (a) their preferences for research methods and (b) technological capabilities of their computers and phones. Facebook's paid advertising program was used to recruit parent caregivers of children currently living with cancer to complete an electronic survey about research preferences and technological capabilities. The advertising campaign generated 3 897 981 impressions, which resulted in 1050 clicks at a total cost of $1129.88. Of 284 screened individuals, 106 were eligible. Forty-five caregivers of children with cancer completed the entire electronic survey. Parents preferred and had technological capabilities for Web-based and electronic research methods. Participant survey responses are reported. Facebook was a useful, cost-effective method to recruit a diverse sample of parent caregivers of children with cancer. Web-based video recording and data collection may be feasible and desirable in samples of children with cancer and their families. Web-based methods (eg, Facebook, Skype) may enhance communication and access between nurses and pediatric oncology patients and their families.

Prevalence and Determinants of Suboptimal Vitamin D Levels in a Multiethnic Asian Population.

PubMed

Man, Ryan Eyn Kidd; Li, Ling-Jun; Cheng, Ching-Yu; Wong, Tien Yin; Lamoureux, Ecosse; Sabanayagam, Charumathi

2017-03-22

This population-based cross-sectional study examined the prevalence and risk factors of suboptimal vitamin D levels (assessed using circulating 25-hydroxycholecalciferol (25(OH)D)) in a multi-ethnic sample of Asian adults. Plasma 25(OH)D concentration of 1139 Chinese, Malay and Indians (40-80 years) were stratified into normal (≥30 ng/mL), and suboptimal (including insufficiency and deficiency, <30 ng/mL) based on the 2011 Endocrine Society Clinical Practice Guidelines. Logistic regression models were used to assess the associations of demographic, lifestyle and clinical risk factors with the outcome. Of the 1139 participants, 25(OH)D concentration was suboptimal in 76.1%. In multivariable models, age ≤65 years (compared to age >65 years), Malay and Indian ethnicities (compared to Chinese ethnicity), and higher body mass index, HbA1c, education and income levels were associated with suboptimal 25(OH)D concentration ( p < 0.05). In a population-based sample of Asian adults, approximately 75% had suboptimal 25(OH)D concentration. Targeted interventions and stricter reinforcements of existing guidelines for vitamin D supplementation are needed for groups at risk of vitamin D insufficiency/deficiency.

Prevalence and Determinants of Suboptimal Vitamin D Levels in a Multiethnic Asian Population

PubMed Central

Man, Ryan Eyn Kidd; Li, Ling-Jun; Cheng, Ching-Yu; Wong, Tien Yin; Lamoureux, Ecosse; Sabanayagam, Charumathi

2017-01-01

This population-based cross-sectional study examined the prevalence and risk factors of suboptimal vitamin D levels (assessed using circulating 25-hydroxycholecalciferol (25(OH)D)) in a multi-ethnic sample of Asian adults. Plasma 25(OH)D concentration of 1139 Chinese, Malay and Indians (40–80 years) were stratified into normal (≥30 ng/mL), and suboptimal (including insufficiency and deficiency, <30 ng/mL) based on the 2011 Endocrine Society Clinical Practice Guidelines. Logistic regression models were used to assess the associations of demographic, lifestyle and clinical risk factors with the outcome. Of the 1139 participants, 25(OH)D concentration was suboptimal in 76.1%. In multivariable models, age ≤65 years (compared to age >65 years), Malay and Indian ethnicities (compared to Chinese ethnicity), and higher body mass index, HbA1c, education and income levels were associated with suboptimal 25(OH)D concentration (p < 0.05). In a population-based sample of Asian adults, approximately 75% had suboptimal 25(OH)D concentration. Targeted interventions and stricter reinforcements of existing guidelines for vitamin D supplementation are needed for groups at risk of vitamin D insufficiency/deficiency. PMID:28327512

The use and correlates of illicit silicone or “fillers” in a population-based sample of transwomen, San Francisco, 2013

PubMed Central

Wilson, Erin; Rapues, Jenna; Jin, Harry; Raymond, H. Fisher

2014-01-01

Introduction There is a dearth of studies to quantify the use of illicit fillers by transwomen. Case studies of illicit filler injections have pointed to an array of serious health complications, including death. Aim The aim of this study was to determine the population prevalence of filler use among transwomen, and to identify correlations with filler use. Methods An analysis of data collected in 2013 with a population-based sample of 234 transwomen recruited using respondent driven sampling (RDS). We used RDS weights to conduct bivariate and multivariate analyses of correlates of filler use. Main Outcome measures Main outcome measures were an RDS-weighted population prevalence of filler use among transwomen and differences in demographic characteristics, transition-related care factors and self-esteem related to appearance. Results Weighted filler prevalence among transwomen was 16.7%. Being a transwomen between 30–49 years of age, owning/renting or living with a partner/family/friend, having had and planning to have surgery in the future and having used non-prescribed hormones were all associated with filler use. HIV was not associated with filler use. Conclusions This study provides the first known estimate to date of the prevalence of filler use in a population-based sample of transwomen in San Francisco. Accessing illicit fillers may be the only choice available for many transwomen due to the cost of legal surgeries and other procedures to change one’s appearance. An important next step in this research is to determine the overall prevalence and long-term consequences of filler use among transwomen, to explore how the use of fillers is protective to the safety and wellbeing of transwomen, and to find safe and affordable alternatives to this method that meets important gender-related appearance needs. PMID:24810672

Genetic determinants of freckle occurrence in the Spanish population: Towards ephelides prediction from human DNA samples.

PubMed

Hernando, Barbara; Ibañez, Maria Victoria; Deserio-Cuesta, Julio Alberto; Soria-Navarro, Raquel; Vilar-Sastre, Inca; Martinez-Cadenas, Conrado

2018-03-01

Prediction of human pigmentation traits, one of the most differentiable externally visible characteristics among individuals, from biological samples represents a useful tool in the field of forensic DNA phenotyping. In spite of freckling being a relatively common pigmentation characteristic in Europeans, little is known about the genetic basis of this largely genetically determined phenotype in southern European populations. In this work, we explored the predictive capacity of eight freckle and sunlight sensitivity-related genes in 458 individuals (266 non-freckled controls and 192 freckled cases) from Spain. Four loci were associated with freckling (MC1R, IRF4, ASIP and BNC2), and female sex was also found to be a predictive factor for having a freckling phenotype in our population. After identifying the most informative genetic variants responsible for human ephelides occurrence in our sample set, we developed a DNA-based freckle prediction model using a multivariate regression approach. Once developed, the capabilities of the prediction model were tested by a repeated 10-fold cross-validation approach. The proportion of correctly predicted individuals using the DNA-based freckle prediction model was 74.13%. The implementation of sex into the DNA-based freckle prediction model slightly improved the overall prediction accuracy by 2.19% (76.32%). Further evaluation of the newly-generated prediction model was performed by assessing the model's performance in a new cohort of 212 Spanish individuals, reaching a classification success rate of 74.61%. Validation of this prediction model may be carried out in larger populations, including samples from different European populations. Further research to validate and improve this newly-generated freckle prediction model will be needed before its forensic application. Together with DNA tests already validated for eye and hair colour prediction, this freckle prediction model may lead to a substantially more detailed physical description of unknown individuals from DNA found at the crime scene. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of TREM2 rs75932628 association with Alzheimer's disease in a population-based sample: the Cache County Study.

PubMed

Gonzalez Murcia, Josue D; Schmutz, Cameron; Munger, Caitlin; Perkes, Ammon; Gustin, Aaron; Peterson, Michael; Ebbert, Mark T W; Norton, Maria C; Tschanz, Joann T; Munger, Ronald G; Corcoran, Christopher D; Kauwe, John S K

2013-12-01

Recent studies have identified the rs75932628 (R47H) variant in TREM2 as an Alzheimer's disease risk factor with estimated odds ratio ranging from 2.9 to 5.1. The Cache County Memory Study is a large, population-based sample designed for the study of memory and aging. We genotyped R47H in 2974 samples (427 cases and 2540 control subjects) from the Cache County study using a custom TaqMan assay. We observed 7 heterozygous cases and 12 heterozygous control subjects with an odds ratio of 3.5 (95% confidence interval, 1.3-8.8; p = 0.0076). The minor allele frequency and population attributable fraction for R47H were 0.0029 and 0.004, respectively. This study replicates the association between R47H and Alzheimer's disease risk in a large, population-based sample, and estimates the population frequency and attributable risk of this rare variant. Copyright © 2013 Elsevier Inc. All rights reserved.

Mental disorder and long-term risk of mortality: 41 years of follow-up of a population sample in Stockholm, Sweden.

PubMed

Lundin, A; Modig, K; Halldin, J; Carlsson, A C; Wändell, P; Theobald, H

2016-08-01

An increased mortality risk associated with mental disorder has been reported for patients, but there are few studies are based on random samples with interview-based psychiatric diagnoses. Part of the increased mortality for those with mental disorder may be attributable to worse somatic health or hazardous health behaviour - consequences of the disorder - but somatic health information is commonly lacking in psychiatric samples. This study aims to examine long-term mortality risk for psychiatric diagnoses in a general population sample and to assess mediation by somatic ill health and hazardous health behaviour. We used a double-phase stratified random sample of individuals aged 18-65 in Stockholm County 1970-1971 linked to vital records. First phase sample was 32 186 individuals screened with postal questionnaire and second phase was 1896 individuals (920 men and 976 women) that participated in a full-day examination (participation rate 88%). Baseline examination included both a semi-structured interview with a psychiatrist, with mental disorders set according to the 8th version of the International Classification of Disease (ICD-8), and clinical somatic examination, including measures of body composition (BMI), hypertension, fasting blood glucose, pulmonary function and self-reported tobacco smoking. Information on vital status was obtained from the Total Population Register for the years 1970-2011. Associations with mortality were studied with Cox proportional hazard analyses. A total of 883 deaths occurred among the participants during the 41-year follow-up. Increased mortality rates were found for ICD-8 functional psychoses (hazard ratio, HR = 2.22, 95% confidence interval (95% CI): 1.15-4.30); psycho-organic symptoms (HR = 1.94, 95% CI: 1.31-2.87); depressive neuroses (HR = 1.71, 95% CI: 1.23-2.39); alcohol use disorder (HR = 1.91, 95% CI: 1.40-2.61); drug dependence (HR = 3.71, 95% CI: 1.80-7.65) and psychopathy (HR = 2.88, 95% CI: 1.02-8.16). Non-participants (n = 349) had mortality rates similar to participants (HR = 0.98, 95% CI: 0.81-1.18). In subgroup analyses of those with psychoses, depression or alcohol use disorder, adjusting for the potential mediators smoking and pulmonary function, showed only slight changes in the HRs. This study confirms the increased risk of mortality for several psychiatric diagnoses in follow-up studies on American, Finnish and Swedish population-based samples. Only a small part of the increased mortality hazard was attributable to differences in somatic health or hazardous health behaviour measured at baseline.

Drug-drug interaction predictions with PBPK models and optimal multiresponse sampling time designs: application to midazolam and a phase I compound. Part 1: comparison of uniresponse and multiresponse designs using PopDes.

PubMed

Chenel, Marylore; Bouzom, François; Aarons, Leon; Ogungbenro, Kayode

2008-12-01

To determine the optimal sampling time design of a drug-drug interaction (DDI) study for the estimation of apparent clearances (CL/F) of two co-administered drugs (SX, a phase I compound, potentially a CYP3A4 inhibitor, and MDZ, a reference CYP3A4 substrate) without any in vivo data using physiologically based pharmacokinetic (PBPK) predictions, population PK modelling and multiresponse optimal design. PBPK models were developed with AcslXtreme using only in vitro data to simulate PK profiles of both drugs when they were co-administered. Then, using simulated data, population PK models were developed with NONMEM and optimal sampling times were determined by optimizing the determinant of the population Fisher information matrix with PopDes using either two uniresponse designs (UD) or a multiresponse design (MD) with joint sampling times for both drugs. Finally, the D-optimal sampling time designs were evaluated by simulation and re-estimation with NONMEM by computing the relative root mean squared error (RMSE) and empirical relative standard errors (RSE) of CL/F. There were four and five optimal sampling times (=nine different sampling times) in the UDs for SX and MDZ, respectively, whereas there were only five sampling times in the MD. Whatever design and compound, CL/F was well estimated (RSE < 20% for MDZ and <25% for SX) and expected RSEs from PopDes were in the same range as empirical RSEs. Moreover, there was no bias in CL/F estimation. Since MD required only five sampling times compared to the two UDs, D-optimal sampling times of the MD were included into a full empirical design for the proposed clinical trial. A joint paper compares the designs with real data. This global approach including PBPK simulations, population PK modelling and multiresponse optimal design allowed, without any in vivo data, the design of a clinical trial, using sparse sampling, capable of estimating CL/F of the CYP3A4 substrate and potential inhibitor when co-administered together.

Periodic Limb Movements During Sleep: Population Prevalence, Clinical Correlates, and Racial Differences

PubMed Central

Scofield, Holly; Roth, Thomas; Drake, Christopher

2008-01-01

Study Objective: There is growing interest in the study of periodic limb movements during sleep and their potential clinical correlates. The aim of the present analysis is to address the lack of population-based studies using polysomnographic (PSG) measures to determine the prevalence of period limb movements during sleep in specific racial groups as well as the general population. Settings and participants: A community-based sample of 592 participants drawn from the general population of tricounty Detroit (mean age = 41.9 ± 12.6 years; 52.9% F; 31.5% African American). All individuals were assessed using objective and subjective measures in the sleep laboratory. Measurements: Participants were evaluated during a 24-h laboratory assessment, including a polysomnogram and multiple sleep latency test. Periodic leg movements were scored using standard criteria. Reports of sleep disturbance and daytime sleepiness were also assessed using standardized measures including the Global Sleep Assessment Questionnaire (GSAQ) and the Epworth Sleepiness Scale (ESS). Results: The overall prevalence of periodic limb movements during sleep (PLMSI >15) was 7.6%. African Americans had a lower prevalence of PLMSI >15 than Caucasians (4.3% vs. 9.3%; Χ2 = 4.5, P < 0.05). Regardless of race, symptoms of insomnia were significantly higher in individuals with PLMSI >15 than in those with PLMSI ≤15 (45% vs. 25%; Χ2 = 6.84, P < 0.01). Conclusion: This is the first study to determine the prevalence of PLMS in a population-based sample using standardized objective criteria. A key finding of the present study is that racial differences in this PSG parameter do exist, with African Americans being less likely to have elevated PLMS. Citation: Scofield H; Roth T; Drake C. Periodic limb movements during sleep: population prevalence, clinical correlates, and racial differences. SLEEP 2008;31(9):1221-1227. PMID:18788647

Single nucleotide polymorphisms in native South American Atlantic coast populations of smooth shelled mussels: hybridization with invasive European Mytilus galloprovincialis.

PubMed

Zbawicka, Małgorzata; Trucco, María I; Wenne, Roman

2018-02-22

Throughout the world, harvesting of mussels Mytilus spp. is based on the exploitation of natural populations and aquaculture. Aquaculture activities include transfers of spat and live adult mussels between various geographic locations, which may result in large-scale changes in the world distribution of Mytilus taxa. Mytilus taxa are morphologically similar and difficult to distinguish. In spite of much research on taxonomy, evolution and geographic distribution, the native Mytilus taxa of the Southern Hemisphere are poorly understood. Recently, single nucleotide polymorphisms (SNPs) have been used to clarify the taxonomic status of populations of smooth shelled mussels from the Pacific coast of South America. In this paper, we used a set of SNPs to characterize, for the first time, populations of smooth shelled mussels Mytilus from the Atlantic coast of South America. Mytilus spp. samples were collected from eastern South America. Six reference samples from the Northern Hemisphere were used: Mytilus edulis from USA and Northern Ireland, Mytilus trossulus from Canada, and Mytilus galloprovincialis from Spain and Italy. Two other reference samples from the Southern Hemisphere were included: M. galloprovincialis from New Zealand and Mytilus chilensis from Chile. Fifty-five SNPs were successfully genotyped, of which 51 were polymorphic. Population genetic analyses using the STRUCTURE program revealed the clustering of eight populations from Argentina (Mytilus platensis) and the clustering of the sample from Ushuaia with M. chilensis from Chile. All individuals in the Puerto Madryn (Argentina) sample were identified as M. platensis × M. galloprovincialis F2 (88.89%) hybrids, except one that was classified as Mediterranean M. galloprovincialis. No F1 hybrids were observed. We demonstrate that M. platensis (or Mytilus edulis platensis) and M. chilensis are distinct native taxa in South America, which indicates that the evolutionary histories of Mytilus taxa along the Atlantic and Pacific coasts differ. M. platensis is endangered by hybridization with M. galloprovincialis that was introduced from Europe into the Puerto Madryn area in Argentina, presumably by accidental introduction via ship traffic. We confirm the occurrence of a native M. chilensis population in southern Argentina on the coast of Patagonia.

Population data for 15 Y-chromosome STRs in a population sample from Quito (Ecuador).

PubMed

Baeza, Carlos; Guzmán, Rodrigo; Tirado, Miriam; López-Parra, Ana María; Rodríguez, Tatiana; Mesa, María Soledad; Fernández, Eva; Arroyo-Pardo, Eduardo

2007-12-20

Population frequencies for the 9 Y-STR loci included in the "minimal haplotype" from Y-STR Haplotype Reference Database (YHRD), plus other 6 Y-STRs (DYS437, DYS438, DYS439, GATA A7.2, GATA H4 and GATA A10) were obtained for a sample of 120 males from Quito (Ecuador). One hundred and sixteen unique haplotypes were identified within the sample. Haplotype diversity (0.9994) was among the highest in comparison to other populations from Iberia and South-America. Genetic distances were calculated and our sample presented significative differences with all other samples, the lowest values being with a Guinean sample.

Paternal genetic affinity between Western Austronesians and Daic populations.

PubMed

Li, Hui; Wen, Bo; Chen, Shu-Juo; Su, Bing; Pramoonjago, Patcharin; Liu, Yangfan; Pan, Shangling; Qin, Zhendong; Liu, Wenhong; Cheng, Xu; Yang, Ningning; Li, Xin; Tran, Dinhbinh; Lu, Daru; Hsu, Mu-Tsu; Deka, Ranjan; Marzuki, Sangkot; Tan, Chia-Chen; Jin, Li

2008-05-15

Austronesian is a linguistic family spread in most areas of the Southeast Asia, the Pacific Ocean, and the Indian Ocean. Based on their linguistic similarity, this linguistic family included Malayo-Polynesians and Taiwan aborigines. The linguistic similarity also led to the controversial hypothesis that Taiwan is the homeland of all the Malayo-Polynesians, a hypothesis that has been debated by ethnologists, linguists, archaeologists, and geneticists. It is well accepted that the Eastern Austronesians (Micronesians and Polynesians) derived from the Western Austronesians (Island Southeast Asians and Taiwanese), and that the Daic populations on the mainland are supposed to be the headstream of all the Austronesian populations. In this report, we studied 20 SNPs and 7 STRs in the non-recombining region of the 1,509 Y chromosomes from 30 China Daic populations, 23 Indonesian and Vietnam Malayo-Polynesian populations, and 11 Taiwan aboriginal populations. These three groups show many resemblances in paternal lineages. Admixture analyses demonstrated that the Daic populations are hardly influenced by Han Chinese genetically, and that they make up the largest proportion of Indonesians. Most of the population samples contain a high frequency of haplogroup O1a-M119, which is nearly absent in other ethnic families. The STR network of haplogroup O1a* illustrated that Indonesian lineages did not derive from Taiwan aborigines as linguistic studies suggest, but from Daic populations. We show that, in contrast to the Taiwan homeland hypothesis, the Island Southeast Asians do not have a Taiwan origin based on their paternal lineages. Furthermore, we show that both Taiwan aborigines and Indonesians likely derived from the Daic populations based on their paternal lineages. These two populations seem to have evolved independently of each other. Our results indicate that a super-phylum, which includes Taiwan aborigines, Daic, and Malayo-Polynesians, is genetically educible.

Microbial assessment of cabin air quality on commercial airliners

NASA Technical Reports Server (NTRS)

La Duc, Myron T.; Stuecker, Tara; Bearman, Gregory; Venkateswaran, Kasthuri

2005-01-01

The microbial burdens of 69 cabin air samples collected from commercial airliners were assessed via conventional culture-dependent, and molecular-based microbial enumeration assays. Cabin air samples from each of four separate flights aboard two different carriers were collected via air-impingement. Microbial enumeration techniques targeting DNA, ATP, and endotoxin were employed to estimate total microbial burden. The total viable microbial population ranged from 0 to 3.6 x10 4 cells per 100 liters of air, as assessed by the ATP-assay. When these same samples were plated on R2A minimal medium, anywhere from 2% to 80% of these viable populations were cultivable. Five of the 29 samples examined exhibited higher cultivable counts than ATP derived viable counts, perhaps a consequence of the dormant nature (and thus lower concentration of intracellular ATP) of cells inhabiting these air cabin samples. Ribosomal RNA gene sequence analysis showed these samples to consist of a moderately diverse group of bacteria, including human pathogens. Enumeration of ribosomal genes via quantitative-PCR indicated that population densities ranged from 5 x 10 1 ' to IO 7 cells per 100 liters of air. Each of the aforementioned strategies for assessing overall microbial burden has its strengths and weaknesses; this publication serves as a testament to the power of their use in concert.

Efficient inference of population size histories and locus-specific mutation rates from large-sample genomic variation data.

PubMed

Bhaskar, Anand; Wang, Y X Rachel; Song, Yun S

2015-02-01

With the recent increase in study sample sizes in human genetics, there has been growing interest in inferring historical population demography from genomic variation data. Here, we present an efficient inference method that can scale up to very large samples, with tens or hundreds of thousands of individuals. Specifically, by utilizing analytic results on the expected frequency spectrum under the coalescent and by leveraging the technique of automatic differentiation, which allows us to compute gradients exactly, we develop a very efficient algorithm to infer piecewise-exponential models of the historical effective population size from the distribution of sample allele frequencies. Our method is orders of magnitude faster than previous demographic inference methods based on the frequency spectrum. In addition to inferring demography, our method can also accurately estimate locus-specific mutation rates. We perform extensive validation of our method on simulated data and show that it can accurately infer multiple recent epochs of rapid exponential growth, a signal that is difficult to pick up with small sample sizes. Lastly, we use our method to analyze data from recent sequencing studies, including a large-sample exome-sequencing data set of tens of thousands of individuals assayed at a few hundred genic regions. © 2015 Bhaskar et al.; Published by Cold Spring Harbor Laboratory Press.

Young adults' trajectories of Ecstasy use: a population based study.

PubMed

Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Plotnikova, Maria; Wells, Helene; Legosz, Margot; Kemp, Robert

2013-11-01

Young adults' Ecstasy use trajectories have important implications for individual and population-level consequences of Ecstasy use, but little relevant research has been conducted. This study prospectively examines Ecstasy trajectories in a population-based sample. Data are from the Natural History Study of Drug Use, a retrospective/prospective cohort study conducted in Australia. Population screening identified a probability sample of Ecstasy users aged 19-23 years. Complete data for 30 months of follow-up, comprising 4 time intervals, were available for 297 participants (88.4% of sample). Trajectories were derived using cluster analysis based on recent Ecstasy use at each interval. Trajectory predictors were examined using a generalized ordered logit model and included Ecstasy dependence (World Mental Health Composite International Diagnostic Instrument), psychological distress (Hospital Anxiety Depression Scale), aggression (Young Adult Self Report) and contextual factors (e.g. attendance at electronic/dance music events). Three Ecstasy trajectories were identified (low, intermediate and high use). At its peak, the high-use trajectory involved 1-2 days Ecstasy use per week. Decreasing frequency of use was observed for intermediate and high-use trajectories from 12 months, independently of market factors. Intermediate and high-use trajectory membership was predicted by past Ecstasy consumption (>70 pills) and attendance at electronic/dance music events. High-use trajectory members were unlikely to have used Ecstasy for more than 3 years and tended to report consistently positive subjective effects at baseline. Given the social context and temporal course of Ecstasy use, Ecstasy trajectories might be better understood in terms of instrumental rather than addictive drug use patterns. © 2013 Elsevier Ltd. All rights reserved.

Population impact of a high cardiovascular risk management program delivered by village doctors in rural China: design and rationale of a large, cluster-randomized controlled trial.

PubMed

Yan, Lijing L; Fang, Weigang; Delong, Elizabeth; Neal, Bruce; Peterson, Eric D; Huang, Yining; Sun, Ningling; Yao, Chen; Li, Xian; MacMahon, Stephen; Wu, Yangfeng

2014-04-11

The high-risk strategy has been proven effective in preventing cardiovascular disease; however, the population benefits from these interventions remain unknown. This study aims to assess, at the population level, the effects of an evidence-based high cardiovascular risk management program delivered by village doctors in rural China. The study will employ a cluster-randomized controlled trial in which a total of 120 villages in five northern provinces of China, will be assigned to either intervention (60 villages) or control (60 villages). Village doctors in intervention villages will be trained to implement a simple evidence-based management program designed to identify, treat and follow-up as many as possible individuals at high-risk of cardiovascular disease in the village. The intervention will also include performance feedback as well as a performance-based incentive payment scheme and will last for 2 years. We will draw two different (independent) random samples, before and after the intervention, 20 men aged≥50 years and 20 women aged≥60 years from each village in each sample and a total of 9,600 participants from 2 samples to measure the study outcomes at the population level. The primary outcome will be the pre-post difference in mean systolic blood pressure, analyzed with a generalized estimating equations extension of linear regression model to account for cluster effect. Secondary outcomes will include monthly clinic visits, provision of lifestyle advice, use of antihypertensive medications and use of aspirin. Process and economic evaluations will also be conducted. This trial will be the first implementation trial in the world to evaluate the population impact of the high-risk strategy in prevention and control of cardiovascular disease. The results are expected to provide important information (effectiveness, cost-effectiveness, feasibility and acceptability) to guide policy making for rural China as well as other resource-limited countries. The trial is registered at ClinicalTrials.gov (NCT01259700). Date of initial registration is December 13, 2010.

The Vineyard Yeast Microbiome, a Mixed Model Microbial Map

PubMed Central

Setati, Mathabatha Evodia; Jacobson, Daniel; Andong, Ursula-Claire; Bauer, Florian

2012-01-01

Vineyards harbour a wide variety of microorganisms that play a pivotal role in pre- and post-harvest grape quality and will contribute significantly to the final aromatic properties of wine. The aim of the current study was to investigate the spatial distribution of microbial communities within and between individual vineyard management units. For the first time in such a study, we applied the Theory of Sampling (TOS) to sample gapes from adjacent and well established commercial vineyards within the same terroir unit and from several sampling points within each individual vineyard. Cultivation-based and molecular data sets were generated to capture the spatial heterogeneity in microbial populations within and between vineyards and analysed with novel mixed-model networks, which combine sample correlations and microbial community distribution probabilities. The data demonstrate that farming systems have a significant impact on fungal diversity but more importantly that there is significant species heterogeneity between samples in the same vineyard. Cultivation-based methods confirmed that while the same oxidative yeast species dominated in all vineyards, the least treated vineyard displayed significantly higher species richness, including many yeasts with biocontrol potential. The cultivatable yeast population was not fully representative of the more complex populations seen with molecular methods, and only the molecular data allowed discrimination amongst farming practices with multivariate and network analysis methods. Importantly, yeast species distribution is subject to significant intra-vineyard spatial fluctuations and the frequently reported heterogeneity of tank samples of grapes harvested from single vineyards at the same stage of ripeness might therefore, at least in part, be due to the differing microbiota in different sections of the vineyard. PMID:23300721

Rationale, design and methodology for the Navajo Health and Nutrition Survey.

PubMed

White, L L; Goldberg, H I; Gilbert, T J; Ballew, C; Mendlein, J M; Peter, D G; Percy, C A; Mokdad, A H

1997-10-01

As recently as 1990, there was no reservation-wide, population-based health status information about Navajo Indians. To remedy this shortcoming, the Navajo Health and Nutrition Survey was conducted from 1991 to 1992 to assess the health and nutritional status of Navajo Reservation residents using a population-based sample. Using a three-stage design, a representative sample of reservation households was selected for inclusion. All members of selected households 12 y of age and older were invited to participate. A total of 985 people in 459 households participated in the study. Survey protocols were modeled on those of previous national surveys and included a standard blood chemistry profile, complete blood count, oral glucose tolerance test, blood pressure, anthropometric measurements, a single 24-h dietary recall and a questionnaire on health behaviors. The findings from this survey, reported in the accompanying papers, inform efforts to prevent and control chronic disease among the Navajo. Lessons learned from this survey may be of interest to those conducting similar surveys in other American Indian and Alaska Native populations.

Measuring informed choice in population-based reproductive genetic screening: a systematic review

PubMed Central

Ames, Alice Grace; Metcalfe, Sylvia Ann; Archibald, Alison Dalton; Duncan, Rony Emily; Emery, Jon

2015-01-01

Genetic screening and health-care guidelines recommend that programmes should facilitate informed choice. It is therefore important that accurate measures of informed choice are available to evaluate such programmes. This review synthesises and appraises measures used to evaluate informed choice in population-based genetic screening programmes for reproductive risk. Databases were searched for studies offering genetic screening for the purpose of establishing reproductive risk to an adult population sample, in which aspects of informed choice were measured. Studies were included if, at a minimum, measures of uptake of screening and knowledge were used. Searches identified 1462 citations and 76 studies were reviewed in full text; 34 studies met the inclusion criteria. Over 20 different measures of informed choice were used. Many measures lacked adequate validity and reliability data. This systematic review will inform future evaluation of informed choice in population genetic screening programmes. PMID:24848746

An introduction to medical statistics for health care professionals: Hypothesis tests and estimation.

PubMed

Thomas, Elaine

2005-01-01

This article is the second in a series of three that will give health care professionals (HCPs) a sound introduction to medical statistics (Thomas, 2004). The objective of research is to find out about the population at large. However, it is generally not possible to study the whole of the population and research questions are addressed in an appropriate study sample. The next crucial step is then to use the information from the sample of individuals to make statements about the wider population of like individuals. This procedure of drawing conclusions about the population, based on study data, is known as inferential statistics. The findings from the study give us the best estimate of what is true for the relevant population, given the sample is representative of the population. It is important to consider how accurate this best estimate is, based on a single sample, when compared to the unknown population figure. Any difference between the observed sample result and the population characteristic is termed the sampling error. This article will cover the two main forms of statistical inference (hypothesis tests and estimation) along with issues that need to be addressed when considering the implications of the study results. Copyright (c) 2005 Whurr Publishers Ltd.

Determination of HIV Status in African Adults With Discordant HIV Rapid Tests.

PubMed

Fogel, Jessica M; Piwowar-Manning, Estelle; Donohue, Kelsey; Cummings, Vanessa; Marzinke, Mark A; Clarke, William; Breaud, Autumn; Fiamma, Agnès; Donnell, Deborah; Kulich, Michal; Mbwambo, Jessie K K; Richter, Linda; Gray, Glenda; Sweat, Michael; Coates, Thomas J; Eshleman, Susan H

2015-08-01

In resource-limited settings, HIV infection is often diagnosed using 2 rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases. Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and 2 HIV RNA tests. Tie-breaker tests were evaluated, including rapid tests (1 performed in-country), a third-generation enzyme immunoassay, and two fourth-generation tests. Selected samples were further characterized using additional assays. Twenty-nine samples (16.8%) were classified as HIV positive and 24 of those samples (82.8%) had undetectable HIV RNA. Antiretroviral drugs were detected in 1 sample. Sensitivity was 8.3%-43% for the rapid tests; 24.1% for the third-generation enzyme immunoassay; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5% to 91.3%. In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases.

CoMet: a workflow using contig coverage and composition for binning a metagenomic sample with high precision.

PubMed

Herath, Damayanthi; Tang, Sen-Lin; Tandon, Kshitij; Ackland, David; Halgamuge, Saman Kumara

2017-12-28

In metagenomics, the separation of nucleotide sequences belonging to an individual or closely matched populations is termed binning. Binning helps the evaluation of underlying microbial population structure as well as the recovery of individual genomes from a sample of uncultivable microbial organisms. Both supervised and unsupervised learning methods have been employed in binning; however, characterizing a metagenomic sample containing multiple strains remains a significant challenge. In this study, we designed and implemented a new workflow, Coverage and composition based binning of Metagenomes (CoMet), for binning contigs in a single metagenomic sample. CoMet utilizes coverage values and the compositional features of metagenomic contigs. The binning strategy in CoMet includes the initial grouping of contigs in guanine-cytosine (GC) content-coverage space and refinement of bins in tetranucleotide frequencies space in a purely unsupervised manner. With CoMet, the clustering algorithm DBSCAN is employed for binning contigs. The performances of CoMet were compared against four existing approaches for binning a single metagenomic sample, including MaxBin, Metawatt, MyCC (default) and MyCC (coverage) using multiple datasets including a sample comprised of multiple strains. Binning methods based on both compositional features and coverages of contigs had higher performances than the method which is based only on compositional features of contigs. CoMet yielded higher or comparable precision in comparison to the existing binning methods on benchmark datasets of varying complexities. MyCC (coverage) had the highest ranking score in F1-score. However, the performances of CoMet were higher than MyCC (coverage) on the dataset containing multiple strains. Furthermore, CoMet recovered contigs of more species and was 18 - 39% higher in precision than the compared existing methods in discriminating species from the sample of multiple strains. CoMet resulted in higher precision than MyCC (default) and MyCC (coverage) on a real metagenome. The approach proposed with CoMet for binning contigs, improves the precision of binning while characterizing more species in a single metagenomic sample and in a sample containing multiple strains. The F1-scores obtained from different binning strategies vary with different datasets; however, CoMet yields the highest F1-score with a sample comprised of multiple strains.

Determining the Population Size of Pond Phytoplankton.

ERIC Educational Resources Information Center

Hummer, Paul J.

1980-01-01

Discusses methods for determining the population size of pond phytoplankton, including water sampling techniques, laboratory analysis of samples, and additional studies worthy of investigation in class or as individual projects. (CS)

Lifestyle Factors and Premature Ejaculation: Are Physical Exercise, Alcohol Consumption, and Body Mass Index Associated With Premature Ejaculation and Comorbid Erectile Problems?

PubMed

Ventus, Daniel; Jern, Patrick

2016-10-01

Premature ejaculation (PE) is a common sexual problem in men, but its etiology remains uncertain. Lifestyle factors have long been hypothesized to be associated with sexual problems in general and have been proposed as risk factors for PE. To explore associations among physical exercise, alcohol use, body mass index, PE, and erectile dysfunction. A population-based sample of Finnish men and a sample of Finnish men diagnosed with PE were surveyed for statistical comparisons. Participants using selective serotonin reuptake inhibitors or other medications known to affect symptoms of PE were excluded from analyses. Self-report questionnaires: Multiple Indicators of Premature Ejaculation, International Index of Erectile Function-5, Alcohol Use Disorders Identification Test, and Godin Leisure-Time Exercise Questionnaire. The clinical sample reported lower levels of physical exercise (mean = 27.53, SD = 21.01, n = 69) than the population-based sample (mean = 34.68, SD = 22.82, n = 863, t930 = 2.52, P = .012), and the effect size was large (d = 0.85). There was a small negative correlation between levels of physical exercise and symptoms of PE (r = -0.09, P < .01, n = 863) in the population-based sample. The association between physical exercise and PE remained significant after controlling for effects of age, erectile dysfunction, alcohol use, and body mass index. If future studies show that the direction of causality of this association is such that physical activity alleviates PE symptoms, then including physical activity in PE treatment interventions could be a promising addition to treatment regimes. Copyright © 2016 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Chamomile Consumption and Mortality: A Prospective Study of Mexican Origin Older Adults.

PubMed

Howrey, Bret T; Peek, M Kristen; McKee, Juliet M; Raji, Mukaila A; Ottenbacher, Kenneth J; Markides, Kyriakos S

2016-12-01

Approximately 20% of adults use some kind of herbal; however, little data exists from population-based study or clinical trials to support effectiveness of most herbal products. Chamomile is a commonly used herb among older adults of Mexican origin. We examined the effects of herbal chamomile consumption on mortality among older adults of Mexican origin. A sample from the Hispanic Established Populations for Epidemiologic Study of the Elderly, a population-based study of noninstitutionalized Mexican Americans aged 65 and older from five Southwestern states (Texas, California, New Mexico, Colorado, and Arizona). We included all men and women from 2000 to 2007 (n = 1,677). Chamomile was used by 14% of the sample. Cox proportional hazards regression analyses showed that chamomile was associated with a decreased risk of mortality in the total sample (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.55-0.92) and for women (HR 0.67, 95% CI 0.49-0.92) but not for men. In models adjusted for sociodemographic variables, health behaviors, and chronic conditions, chamomile remained significantly associated with reduced mortality in women (HR 0.72, 95% CI 0.53-0.98). The use of chamomile shows protective effects against mortality in this sample of older adults of Mexican origin for women. Further research is warranted in other populations to determine if these effects are consistent. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparison of Online Survey Recruitment Platforms for Hard-to-Reach Pregnant Smoking Populations: Feasibility Study

PubMed Central

Agas, Jessica Marie; Lee, Melissa; Pan, Julia Lily; Buttenheim, Alison Meredith

2018-01-01

Background Recruiting hard-to-reach populations for health research is challenging. Web-based platforms offer one way to recruit specific samples for research purposes, but little is known about the feasibility of online recruitment and the representativeness and comparability of samples recruited through different Web-based platforms. Objective The objectives of this study were to determine the feasibility of recruiting a hard-to-reach population (pregnant smokers) using 4 different Web-based platforms and to compare participants recruited through each platform. Methods A screener and survey were distributed online through Qualtrics Panel, Soapbox Sample, Reddit, and Amazon Mechanical Turk (mTurk). Descriptive statistics were used to summarize results of each recruitment platform, including eligibility yield, quality yield, income, race, age, and gestational age. Results Of the 3847 participants screened for eligibility across all 4 Web-based platforms, 535 were eligible and 308 completed the survey. Amazon mTurk yielded the fewest completed responses (n=9), 100% (9/9) of which passed several quality metrics verifying pregnancy and smoking status. Qualtrics Panel yielded 14 completed responses, 86% (12/14) of which passed the quality screening. Soapbox Sample produced 107 completed surveys, 67% (72/107) of which were found to be quality responses. Advertising through Reddit produced the highest completion rate (n=178), but only 29.2% (52/178) of those surveys passed the quality metrics. We found significant differences in eligibility yield, quality yield, age, number of previous pregnancies, age of smoking initiation, current smokers, race, education, and income (P<.001). Conclusions Although each platform successfully recruited pregnant smokers, results varied in quality, cost, and percentage of complete responses. Moving forward, investigators should pay careful attention to the percentage yield and cost of online recruitment platforms to maximize internal and external validity. PMID:29661751

"Perspectives on financing population-based health care towards Universal Health Coverage among employed individuals in Ghanzi district, Botswana: A qualitative study".

PubMed

Mbogo, Barnabas Africanus; McGill, Deborah

2016-08-19

Globally, about 150 million people experience catastrophic healthcare expenditure services annually. Among low and middle income countries, out-of-pocket expenditure pushes about 100 million people into poverty annually. In Botswana, 83 % of the general population and 58 % of employed individuals do not have medical aid coverage. Moreover, inequity allocation of financial resources between health services suggests marginalization of population-based health care services (i.e. diseases prevention and health promotion). The purpose of the study is to explore perspectives on employed individuals regarding financing population based health care interventions towards Universal Health Coverage (UHC) in order to make recommendations to the Ministry of Health on health financing options to cover population-based health services. A qualitative design grounded in interpretivist epistemology through social constructivism lens was critical for exploring perspectives of employed individuals. Through purposive and snowballing sampling techniques, a total of 15 respondents including 8 males and 7 females were recruited and interviewed using a semi-structured format. Their age ranged from 23 to 59 years with a median of 36 years. Data was analyzed using Thematic Content Analysis technique. Use of social constructivism lens enabled to classify emerging themes into population coverage, health services coverage and financial protection issues. Despite broad understanding of health coverage schemes among participants, knowledge appears insignificant in increasing enrolment. Participants indicated limited understanding of UHC concepts, however showed willingness to embrace UHC upon brief description. Main thematic issues raised include: exclusion of population-based health services from coverage scheme; disparity in financial protection and health services coverage among enrollees; inability to sustain contracted employees; and systematic exclusion of unemployed individuals and informal sector employees. Increasing enrolment in health coverage schemes requires targeted campaign for information dissemination through use of myriads mass media including: social networks, TV, Radio and others. Moreover, re-designing health insurance schemes is critical in order to include population-based interventions; expand uptake of unemployed and informal sector employees; flexibility in monthly premiums payment plan and use of technology to increase access to payment points. Further study need to evaluate the content of health financing policy in Botswana measured against the World Health Organization Universal Health Coverage conceptual requirements for Low and Middle Income Countries.

Augmenting comprehension of geological relationships by integrating 3D laser scanned hand samples within a GIS environment

NASA Astrophysics Data System (ADS)

Harvey, A. S.; Fotopoulos, G.; Hall, B.; Amolins, K.

2017-06-01

Geological observations can be made on multiple scales, including micro- (e.g. thin section), meso- (e.g. hand-sized to outcrop) and macro- (e.g. outcrop and larger) scales. Types of meso-scale samples include, but are not limited to, rocks (including drill cores), minerals, and fossils. The spatial relationship among samples paired with physical (e.g. granulometric composition, density, roughness) and chemical (e.g. mineralogical and isotopic composition) properties can aid in interpreting geological settings, such as paleo-environmental and formational conditions as well as geomorphological history. Field samples are collected along traverses in the area of interest based on characteristic representativeness of a region, predetermined rate of sampling, and/or uniqueness. The location of a sample can provide relative context in seeking out additional key samples. Beyond labelling and recording of geospatial coordinates for samples, further analysis of physical and chemical properties may be conducted in the field and laboratory. The main motivation for this paper is to present a workflow for the digital preservation of samples (via 3D laser scanning) paired with the development of cyber infrastructure, which offers geoscientists and engineers the opportunity to access an increasingly diverse worldwide collection of digital Earth materials. This paper describes a Web-based graphical user interface developed using Web AppBuilder for ArcGIS for digitized meso-scale 3D scans of geological samples to be viewed alongside the macro-scale environment. Over 100 samples of virtual rocks, minerals and fossils populate the developed geological database and are linked explicitly with their associated attributes, characteristic properties, and location. Applications of this new Web-based geological visualization paradigm in the geosciences demonstrate the utility of such a tool in an age of increasing global data sharing.

Prevalence of DSM-5 Autism Spectrum Disorder Among School-Based Children Aged 3-12 Years in Shanghai, China.

PubMed

Jin, Zhijuan; Yang, You; Liu, Shijian; Huang, Hong; Jin, Xingming

2018-02-16

We estimated the prevalence of ASD in a population-based sample comprising children aged 3-12 years (N = 74,252) in Shanghai. This included a high-risk group sampled from special education schools and a low-risk group randomly sampled from general schools. First, we asked parents and then teachers to complete the Social Communication Questionnaire for participating children. Children who screened positive based on both parental and teachers' reports were comprehensively assessed. ASD was identified based on DSM-5 criteria. We identified 711 children as being at-risk for ASD, of which 203 were identified as ASD cases. The prevalence of ASD was 8.3 per 10,000, which is likely an underestimate, given that 81.6% of the children diagnosed with ASD had IQs below 40. This is the first report on the prevalence of ASD according to DSM-5 in China.

Altered self-perception in adult survivors treated for a CNS tumor in childhood or adolescence: population-based outcomes compared with the general population.

PubMed

Hörnquist, Lina; Rickardsson, Jenny; Lannering, Birgitta; Gustafsson, Göran; Boman, Krister K

2015-05-01

Survivors of pediatric CNS tumors are at risk for persistent tumor/treatment-related morbidity, physical disability and social consequences that may alter self-perception, vital for self-identity, mental health and quality of survival. We studied the long-term impact of childhood CNS tumors and their treatment on the self-perception of adult survivors and compared outcomes with those of the general population. The cohort included 697 Swedish survivors diagnosed with a primary CNS tumor during 1982-2001. Comparison data were randomly collected from a stratified general population sample. Survivors and general population individuals were compared as regards self-perception in 5 domains: body image, sports/physical activities, peers, work, and family, and with a global self-esteem index. Within the survivor group, determinants of impact on self-perception were identified. The final analyzed sample included 528 survivors, 75.8% of the entire national cohort. The control sample consisted of 995, 41% of 2500 addressed. Survivors had significantly poorer self-perception outcomes in domains of peers, work, body image, and sports/physical activities, and in the global self-perception measure, compared with those of the general population (all P < .001). Within the survivor group, female gender and persistent visible physical sequelae predicted poorer outcomes in several of the studied domains. Tumor type and a history of cranial radiation therapy were associated with outcomes. An altered self-perception is a potential late effect in adult survivors of pediatric CNS tumors. Self-perception and self-esteem are significant elements of identity, mental health and quality of survival. Therefore, care and psychosocial follow-up of survivors should include measures for identifying disturbances and for assessing the need for psychosocial intervention. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Development of System Thinking Skills in the Context of Earth System Education

ERIC Educational Resources Information Center

Assaraf, Orit Ben-Zvi; Orion, Nir

2005-01-01

The current study deals with the development of system thinking skills at the junior high school level. The sample population included about 50 eighth-grade students from two different classes of an urban Israeli junior high school who studied an earth systems-based curriculum that focused on the hydro cycle. The study addressed the following…

Prevalence of Childhood Sexual Abuse among Incarcerated Males in County Jail

ERIC Educational Resources Information Center

Johnson, Regina J.; Ross, Michael W.; Taylor, Wendell C.; Williams, Mark L.; Carvajal, Raul I.; Peters, Ronald J.

2006-01-01

Objective: The current study examined the prevalence and characteristics of childhood sexual abuse in a jailed-based population. Methodology: A retrospective, self-reported survey was administered over an 8-week period to a random sample of 100 men who were incarcerated in a county jail in Southeastern Texas. The survey included questions about…

The Epidemiology of Homicide Followed by Suicide: A Systematic and Quantitative Review

ERIC Educational Resources Information Center

Large, Matthew; Smith, Glen; Nielssen, Olav

2009-01-01

This systematic review of population based studies of homicide followed by suicide was conducted to examine the associations between rates of homicide-suicide, rates of other homicides and rates of suicide. The review analysed 64 samples, including the case of an outlier (Greenland) that were reported in 49 studies. There was a significant…

Misclassifications of Hispanics Using Fordisc 3.1: Comparing Cranial Morphology in Asian and Hispanic Populations.

PubMed

Dudzik, Beatrix; Jantz, Richard L

2016-09-01

It has been brought to the attention of the authors of Fordisc 3.1 that Hispanic samples will often misclassify as Japanese when Asian population samples are included. This study examined this problem in an effort to better document the occurrence and deduce possible causes via comparative analyses. Asian and Hispanic samples were first compared utilizing the existing samples from the University of Tennessee's Forensic Data Bank. Additional modern Japanese, Thai, and Korean samples collected by the first author that have previously not been utilized in analyses were subsequently included. Results of this study confirm frequent rates of misclassification among Hispanic and Japanese groups. Furthermore, a close morphological relationship is identified through further group comparisons and the addition of data used in conjunction with Fordisc samples. Similarities identified among Hispanic and Japanese crania may stem from similar population histories reflected in ancestral Native American and East Asian populations. © 2016 American Academy of Forensic Sciences.

A literature review of the cardiovascular risk-assessment tools: applicability among Asian population.

PubMed

Liau, Siow Yen; Mohamed Izham, M I; Hassali, M A; Shafie, A A

2010-01-01

Cardiovascular diseases, the main causes of hospitalisations and death globally, have put an enormous economic burden on the healthcare system. Several risk factors are associated with the occurrence of cardiovascular events. At the heart of efficient prevention of cardiovascular disease is the concept of risk assessment. This paper aims to review the available cardiovascular risk-assessment tools and its applicability in predicting cardiovascular risk among Asian populations. A systematic search was performed using keywords as MeSH and Boolean terms. A total of 25 risk-assessment tools were identified. Of these, only two risk-assessment tools (8%) were derived from an Asian population. These risk-assessment tools differ in various ways, including characteristics of the derivation sample, type of study, time frame of follow-up, end points, statistical analysis and risk factors included. Very few cardiovascular risk-assessment tools were developed in Asian populations. In order to accurately predict the cardiovascular risk of our population, there is a need to develop a risk-assessment tool based on local epidemiological data.

Effects of exploitation on black bear populations at White River National Wildlife Refuge

USGS Publications Warehouse

Clark, J.D.; Eastridge, R.; Hooker, M.J.

2010-01-01

We live-trapped American black bears (Ursus americanus) and sampled DNA from hair at White River National Wildlife Refuge, Arkansas, USA, to estimate annual population size (N), growth (λ), and density. We estimated N and λ with open population models, based on live-trapping data collected from 1998 through 2006, and robust design models for genotyped hair samples collected from 2004 through 2007. Population growth was weakly negative (i.e., 95% CI included 1.0) for males (0.901, 95% CI  =  0.645–1.156) and strongly negative (i.e., 95% CI excluded 1.0) for females (0.846, 95% CI  =  0.711–0.981), based on live-trapping data, with N from 1999 to 2006 ranging from 94.1 (95% CI  =  70.3–137.1) to 45.2 (95% CI  =  27.1–109.3), respectively, for males and from 151.4 (95% CI  =  127.6–185.8) to 47.1 (95% CI  =  24.4–140.4), respectively, for females. Likewise, mean annual λ based on hair-sampling data was weakly negative for males (0.742, 95% CI  =  0.043–1.441) and strongly negative for females (0.782, 95% CI  =  0.661–0.903), with abundance estimates from 2004 to 2007 ranging from 29.1 (95% CI  =  21.2–65.8) to 11.9 (95% CI  =  11.0–26.9), respectively, for males and from 54.4 (95% CI  =  44.3–77.1) to 27.4 (95% CI  = 24.9–36.6), respectively, for females. We attribute the decline in the number of females in this isolated population to a decrease in survival caused by a past translocation program and by hunting adjacent to the refuge. We suggest that managers restructure the quota-based harvest limits until these growth rates recover.

Microsatellites indicate minimal barriers to mule deer Odocoileus hemionus dispersal across Montana, USA

USGS Publications Warehouse

Powell, John H.; Kalinowski, Steven T.; Higgs, Megan D.; Ebinger, Michael R.; Vu, Ninh V.; Cross, Paul C.

2013-01-01

To better understand the future spread of chronic wasting disease, we conducted a genetic assessment of mule deer Odocoileus hemionus population structure across the state of Montana, USA. Individual based analyses were used to test for population structure in the absence of a priori designations of population membership across the sampling area. Samples from the states of Wyoming, Colorado and Utah were also included in the analysis to provide a geographic context to the levels of population structure observed within Montana. Results showed that mule deer across our entire study region were characterized by weak isolation by distance and a lack of spatial autocorrelation at distances > 10 km. We found evidence for contemporary male bias in dispersal, with female mule deer exhibiting higher mean individual pairwise genetic distance than males. We tested for potential homogenizing effects of past translocations within Montana, but were unable to detect a genetic signature of these events. Our results indicate high levels of connectivity among mule deer populations in Montana and suggest few, if any, detectable barriers to mule deer gene flow or chronic wasting disease transmission.

Excavating past population structures by surname-based sampling: the genetic legacy of the Vikings in northwest England

PubMed Central

Bowden, Georgina R.; Balaresque, Patricia; King, Turi E.; Hansen, Ziff; Lee, Andrew C.; Pergl-Wilson, Giles; Hurley, Emma; Roberts, Stephen J.; Waite, Patrick; Jesch, Judith; Jones, Abigail L.; Thomas, Mark G.; Harding, Stephen E.; Jobling, Mark A.

2009-01-01

The genetic structures of past human populations are obscured by recent migrations and expansions, and can been observed only indirectly by inference from modern samples. However, the unique link between a heritable cultural marker, the patrilineal surname, and a genetic marker, the Y chromosome, provides a means to target sets of modern individuals that might resemble populations at the time of surname establishment. As a test case, we studied samples from the Wirral peninsula and West Lancashire, in northwest England. Place names and archaeology show clear evidence of a past Viking presence, but heavy immigration and population growth since the Industrial Revolution are likely to have weakened the genetic signal of a thousand-year-old Scandinavian contribution. Samples ascertained on the basis of two generations of residence were compared with independent samples based on known ancestry in the region, plus the possession of a surname known from historical records to have been present there in medieval times. The Y-chromosomal haplotypes of these two sets of samples are significantly different, and in admixture analyses the surname-ascertained samples show markedly greater Scandinavian ancestry proportions, supporting the idea that northwest England was once heavily populated by Scandinavian settlers. The method of historical surname-based ascertainment promises to allow investigation of the influence of migration and drift over the last few centuries in changing the population structure of Britain, and will have general utility in other regions where surnames are patrilineal and suitable historical records survive. PMID:18032405

USE OF COMMERCIAL TELEPHONE DIRECTORY FOR OBTAINING A POPULATION-BASED SAMPLE OF WOMEN OF REPRODUCTIVE AGE

EPA Science Inventory

Using Commercial Telephone Directories to Obtain a Population-Based Sample for Mail Survey of Women of Reproductive Age

Danelle T. Lobdella, Germaine M. Buckb, John M. Weinerc, Pauline Mendolaa

aUnited States Environmental Protection Agency, Office of Research and ...

Incorporating precision, accuracy and alternative sampling designs into a continental monitoring program for colonial waterbirds

USGS Publications Warehouse

Steinkamp, Melanie J.; Peterjohn, B.G.; Keisman, J.L.

2003-01-01

A comprehensive monitoring program for colonial waterbirds in North America has never existed. At smaller geographic scales, many states and provinces conduct surveys of colonial waterbird populations. Periodic regional surveys are conducted at varying times during the breeding season using a variety of survey methods, which complicates attempts to estimate population trends for most species. The US Geological Survey Patuxent Wildlife Research Center has recently started to coordinate colonial waterbird monitoring efforts throughout North America. A centralized database has been developed with an Internet-based data entry and retrieval page. The extent of existing colonial waterbird surveys has been defined, allowing gaps in coverage to be identified and basic inventories completed where desirable. To enable analyses of comparable data at regional or larger geographic scales, sampling populations through statistically sound sampling designs should supersede obtaining counts at every colony. Standardized breeding season survey techniques have been agreed upon and documented in a monitoring manual. Each survey in the manual has associated with it recommendations for bias estimation, and includes specific instructions on measuring detectability. The methods proposed in the manual are for developing reliable, comparable indices of population size to establish trend information at multiple spatial and temporal scales, but they will not result in robust estimates of total population numbers.

Neurocognitive performance in family-based and case-control studies of schizophrenia.

PubMed

Gur, Ruben C; Braff, David L; Calkins, Monica E; Dobie, Dorcas J; Freedman, Robert; Green, Michael F; Greenwood, Tiffany A; Lazzeroni, Laura C; Light, Gregory A; Nuechterlein, Keith H; Olincy, Ann; Radant, Allen D; Seidman, Larry J; Siever, Larry J; Silverman, Jeremy M; Sprock, Joyce; Stone, William S; Sugar, Catherine A; Swerdlow, Neal R; Tsuang, Debby W; Tsuang, Ming T; Turetsky, Bruce I; Gur, Raquel E

2015-04-01

Neurocognitive deficits in schizophrenia (SZ) are established and the Consortium on the Genetics of Schizophrenia (COGS) investigated such measures as endophenotypes in family-based (COGS-1) and case-control (COGS-2) studies. By requiring family participation, family-based sampling may result in samples that vary demographically and perform better on neurocognitive measures. The Penn computerized neurocognitive battery (CNB) evaluates accuracy and speed of performance for several domains and was administered across sites in COGS-1 and COGS-2. Most tests were included in both studies. COGS-1 included 328 patients with SZ and 497 healthy comparison subjects (HCS) and COGS-2 included 1195 patients and 1009 HCS. Demographically, COGS-1 participants were younger, more educated, with more educated parents and higher estimated IQ compared to COGS-2 participants. After controlling for demographics, the two samples produced very similar performance profiles compared to their respective controls. As expected, performance was better and with smaller effect sizes compared to controls in COGS-1 relative to COGS-2. Better performance was most pronounced for spatial processing while emotion identification had large effect sizes for both accuracy and speed in both samples. Performance was positively correlated with functioning and negatively with negative and positive symptoms in both samples, but correlations were attenuated in COGS-2, especially with positive symptoms. Patients ascertained through family-based design have more favorable demographics and better performance on some neurocognitive domains. Thus, studies that use case-control ascertainment may tap into populations with more severe forms of illness that are exposed to less favorable factors compared to those ascertained with family-based designs.

Multiple, Distinct Intercontinental Lineages but Isolation of Australian Populations in a Cosmopolitan Lichen-Forming Fungal Taxon, Psora decipiens (Psoraceae, Ascomycota)

PubMed Central

Leavitt, Steven D.; Westberg, Martin; Nelsen, Matthew P.; Elix, John A.; Timdal, Einar; Sohrabi, Mohammad; St. Clair, Larry L.; Williams, Laura; Wedin, Mats; Lumbsch, H. T.

2018-01-01

Multiple drivers shape the spatial distribution of species, including dispersal capacity, niche incumbency, climate variability, orographic barriers, and plate tectonics. However, biogeographic patterns of fungi commonly do not fit conventional expectations based on studies of animals and plants. Fungi, in general, are known to occur across exceedingly broad, intercontinental distributions, including some important components of biological soil crust communities (BSCs). However, molecular data often reveal unexpected biogeographic patterns in lichenized fungal species that are assumed to have cosmopolitan distributions. The lichen-forming fungal species Psora decipiens is found on all continents, except Antarctica and occurs in BSCs across diverse habitats, ranging from hot, arid deserts to alpine habitats. In order to better understand factors that shape population structure in cosmopolitan lichen-forming fungal species, we investigated biogeographic patterns in the cosmopolitan taxon P. decipiens, along with the closely related taxa P. crenata and P. saviczii. We generated a multi-locus sequence dataset based on a worldwide sampling of these taxa in order to reconstruct evolutionary relationships and explore phylogeographic patterns. Both P. crenata and P. decipiens were not recovered as monophyletic; and P. saviczii specimens were recovered as a monophyletic clade closely related to a number of lineages comprised of specimens representing P. decipiens. Striking phylogeographic patterns were observed for P. crenata, with populations from distinct geographic regions belonging to well-separated, monophyletic lineages. South African populations of P. crenata were further divided into well-supported sub-clades. While well-supported phylogenetic substructure was also observed for the nominal taxon P. decipiens, nearly all lineages were comprised of specimens collected from intercontinental populations. However, all Australian specimens representing P. decipiens were recovered within a single well-supported monophyletic clade consisting solely of Australian samples. Our study supports up to 10 candidate species-level lineages in P. decipiens, based on genealogical concordance and coalescent-based species delimitation analyses. Our results support the general pattern of the biogeographic isolation of lichen-forming fungal populations in Australia, even in cases where closely related congeners have documented intercontinental distributions. Our study has important implications for understanding factors influencing diversification and distributions of lichens associated with BSC. PMID:29527197

New formulae for estimating stature in the Balkans.

PubMed

Ross, Ann H; Konigsberg, Lyle W

2002-01-01

Recent studies of secular change and allometry have observed differential limb proportions between the sexes, among and within populations. These studies suggest that stature prediction formulae developed from American Whites may be inappropriate for European populations. The purpose of this investigation is to present more appropriate stature prediction equations for use in the Balkans to aid present-day identifications of the victims of genocide. The reference sample totals 545 white males obtained from World War II data. The Eastern European sample totals 177 males and includes both Bosnian and Croatian victims of the recent war. Mean stature for Eastern Europeans was obtained from the literature. Results show that formulae based on Trotter and Gleser systematically underestimate stature in the Balkans. Because Eastern Europeans are taller than American Whites it is appropriate to use this as an "informative prior" that can be applied to future cases. This informative prior can be used in predictive formulae, since it is probably similar to the sample from which the Balkan forensic cases were drawn. Based on Bayes' Theorem new predictive stature formulae are presented for Eastern Europeans.

Cognition in school-aged children with "active" epilepsy: A population-based study.

PubMed

Reilly, Colin; Atkinson, Patricia; Das, Krishna B; Chin, Richard F M; Aylett, Sarah E; Burch, Victoria; Gillberg, Christopher; Scott, Rod C; Neville, Brian G R

2015-01-01

There is a lack of population-based data on specific cognitive profiles in childhood epilepsy. This study sought to determine the frequency of impairments in global cognition and aspects of working memory and processing speed in a population-based sample of children with "active" epilepsy (on antiepileptic Drugs (AEDs), and/or had a seizure in the last year). Factors significantly associated with global and specific difficulties in cognition were also identified. A total of 85 (74% of eligible population) school-aged children (5-15 years) with "active" epilepsy underwent comprehensive psychological assessment including assessment of global cognition, working memory, and processing speed. Scores on cognitive subtests were compared via paired-samples t tests. The factors associated with cognitive difficulties were analyzed via linear regression. A total of 24% of children were functioning below IQ 50, and 40% had IQ scores below 70. Scores on the Processing Speed Index were significantly lower than scores on the Verbal or Performance indexes on Wechsler instruments. The Coding subtest was a significant weakness compared with the other Wechsler subtests. A total of 58% of children displayed "memory underachievement" (memory score 1 SD below assessed IQ) on at least one of the four administered working memory subtests. Factors significantly associated with globally impaired cognition included being on polytherapy (β = -13.0; 95% CI [-19.3, -6.6], p = .000) and having attention-deficit/hyperactivity disorder (ADHD; β = -11.1, 95% CI [-3.0, -19.3], p = .008). Being on polytherapy was also associated with lower scores on the working memory and processing speed composite scores. Having developmental coordination disorder (DCD) was associated with a lower score on the processing speed composite. There is a high rate of global and specific cognitive difficulties in childhood epilepsy. Difficulties are most pronounced in aspects of working memory and processing speed. Predictors of cognitive impairment in childhood epilepsy include epilepsy-related and behavioral factors, which may differ depending on the domain of cognition assessed.

Genetic differentiation among North Atlantic killer whale populations.

PubMed

Foote, Andrew D; Vilstrup, Julia T; De Stephanis, Renaud; Verborgh, Philippe; Abel Nielsen, Sandra C; Deaville, Robert; Kleivane, Lars; Martín, Vidal; Miller, Patrick J O; Oien, Nils; Pérez-Gil, Monica; Rasmussen, Morten; Reid, Robert J; Robertson, Kelly M; Rogan, Emer; Similä, Tiu; Tejedor, Maria L; Vester, Heike; Víkingsson, Gísli A; Willerslev, Eske; Gilbert, M Thomas P; Piertney, Stuart B

2011-02-01

Population genetic structure of North Atlantic killer whale samples was resolved from differences in allele frequencies of 17 microsatellite loci, mtDNA control region haplotype frequencies and for a subset of samples, using complete mitogenome sequences. Three significantly differentiated populations were identified. Differentiation based on microsatellite allele frequencies was greater between the two allopatric populations than between the two pairs of partially sympatric populations. Spatial clustering of individuals within each of these populations overlaps with the distribution of particular prey resources: herring, mackerel and tuna, which each population has been seen predating. Phylogenetic analyses using complete mitogenomes suggested two populations could have resulted from single founding events and subsequent matrilineal expansion. The third population, which was sampled at lower latitudes and lower density, consisted of maternal lineages from three highly divergent clades. Pairwise population differentiation was greater for estimates based on mtDNA control region haplotype frequencies than for estimates based on microsatellite allele frequencies, and there were no mitogenome haplotypes shared among populations. This suggests low or no female migration and that gene flow was primarily male mediated when populations spatially and temporally overlap. These results demonstrate that genetic differentiation can arise through resource specialization in the absence of physical barriers to gene flow. © 2010 Blackwell Publishing Ltd.

Iron Age and Anglo-Saxon genomes from East England reveal British migration history.

PubMed

Schiffels, Stephan; Haak, Wolfgang; Paajanen, Pirita; Llamas, Bastien; Popescu, Elizabeth; Loe, Louise; Clarke, Rachel; Lyons, Alice; Mortimer, Richard; Sayer, Duncan; Tyler-Smith, Chris; Cooper, Alan; Durbin, Richard

2016-01-19

British population history has been shaped by a series of immigrations, including the early Anglo-Saxon migrations after 400 CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences from 10 individuals excavated close to Cambridge in the East of England, ranging from the late Iron Age to the middle Anglo-Saxon period. By analysing shared rare variants with hundreds of modern samples from Britain and Europe, we estimate that on average the contemporary East English population derives 38% of its ancestry from Anglo-Saxon migrations. We gain further insight with a new method, rarecoal, which infers population history and identifies fine-scale genetic ancestry from rare variants. Using rarecoal we find that the Anglo-Saxon samples are closely related to modern Dutch and Danish populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain.

The Evolutionary History of the Rediscovered Austrian Population of the Giant Centipede Scolopendra cingulata Latreille 1829 (Chilopoda, Scolopendromorpha)

PubMed Central

Oeyen, Jan Philip; Funke, Sebastian; Böhme, Wolfgang; Wesener, Thomas

2014-01-01

The thermophilous giant centipede Scolopendra cingulata is a voracious terrestrial predator, which uses its modified first leg pair and potent venom to capture prey. The highly variable species is the most common of the genus in Europe, occurring from Portugal in the west to Iran in the east. The northernmost occurrences are in Hungary and Romania, where it abides in small isolated fringe populations. We report the rediscovery of an isolated Austrian population of Scolopendra cingulata with the first explicit specimen records for more than 80 years and provide insights into the evolutionary history of the northernmost populations utilizing fragments of two mitochondrial genes, COI and 16S, comprising 1,155 base pairs. We test the previously proposed hypothesis of a speciation by distance scenario, which argued for a simple range expansion of the species from the southeast, via Romania, Hungary and finally to Austria, based on a comprehensive taxon sampling from seven countries, including the first European mainland samples. We argue that more complex patterns must have shaped the current distribution of S. cingulata and that the Austrian population should be viewed as an important biogeographical relict in a possible microrefugium. The unique haplotype of the Austrian population could constitute an important part of the species genetic diversity and we hope that this discovery will initiate protective measures not only for S. cingulata, but also for its habitat, since microrefugia are likely to host further rare thermophilous species. Furthermore, we take advantage of the unprecedented sampling to provide the first basic insights into the suitability of the COI fragment as a species identifying barcode within the centipede genus Scolopendra. PMID:25251436

COMPARISON OF SAMPLING TECHNIQUES USED IN STUDYING LEPIDOPTERA POPULATION DYNAMICS

EPA Science Inventory

Four methods (light traps, foliage samples, canvas bands, and gypsy moth egg mass surveys) that are used to study the population dynamics of foliage-feeding Lepidoptera were compared for 10 species, including gypsy moth, Lymantria dispar L. Samples were collected weekly at 12 sit...

Can we use postal surveys with anonymous testing to monitor chlamydia prevalence in young women in England? Pilot study incorporating randomised controlled trial of recruitment methods.

PubMed

Woodhall, Sarah C; Nichols, Tom; Alexander, Sarah; da Silva, Filomeno Coelho; Mercer, Catherine H; Ison, Catherine; Gill, O Noel; Soldan, Kate

2015-09-01

Chlamydia prevalence in the general population is a potential outcome measure for the evaluation of chlamydia control programmes. We carried out a pilot study to determine the feasibility of using a postal survey for population-based chlamydia prevalence monitoring. Postal invitations were sent to a random sample of 2000 17-year-old to 18-year-old women registered with a general practitioner in two pilot areas in England. Recipients were randomised to receive either a self-sampling kit (n=1000), a self-sampling kit and offer of £5 voucher on return of sample (n=500) or a self-sampling kit on request (n=500). Participants returned a questionnaire and self-taken vulvovaginal swab sample for unlinked anonymous Chlamydia trachomatis testing. Non-responders were sent a reminder letter 3 weeks after initial invitation. We calculated the participation rate (number of samples returned/number of invitations sent) and cost per sample returned (including cost of consumables and postage) in each group. A total of 155/2000 (7.8%) samples were returned with consent for testing. Participation rates varied by invitation group: 7.8% in the group who were provided with a self-sampling kit, 14% in the group who were also offered a voucher and 1.0% in the group who were not sent a kit. The cost per sample received was lowest (£36) in the group who were offered both a kit and a voucher. The piloted survey methodology achieved low participation rates. This approach is not suitable for population-based monitoring of chlamydia prevalence among young women in England. (UKCRN ID 10913). 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.

Sexting Behaviors Exhibited by Men Who Have Sex with Men Between the Ages of 18-70 Who Live in a Socially Conservative State.

PubMed

Currin, Joseph M; Hubach, Randolph D

2017-07-01

Sexting, defined as the sending and receiving of sexually suggestive or sexually explicit text or photos, has been growing in prevalence. Recent studies have demonstrated that over half of individuals sampled over 17 and regardless of gender participate in some type of sexting behavior. Most studies on sexting behaviors, including those looking at men who have sex with men (MSM) focus on emerging adult or university-based populations. The goal of the current study was to sample a nonuniversity-based MSM adult population to determine the prevalence of sexting behavior and the odds that a person engages in sexting behaviors based on certain sexual behaviors. The sample consisted of 213 MSM (mean age = 34.8 years, standard deviation [STD] = 12.1) who reside in Oklahoma. The majority of participants (133, 62.4 percent) participated in sexting behaviors. Logistic regression indicated that individuals had 10 times higher odds to engage in sexting if they had participated in a hookup (odds ratio [OR] = 10.44, 95% CI = [4.16-26.25]) and individuals who are married or in a committed relationship had 71 percent lower odds that they had sent a sext message (OR = 0.29, 95% CI = [0.12-0.71]). Sexting behaviors were not associated with condom use. Implications, including using third-party geolocation mobile application (such as Grindr) to deliver sexual health information, are discussed.

Differences in prevalence of parasites in stool samples between three distinct ethnic pediatric populations in southern Israel, 2007-2011.

PubMed

Ben-Shimol, Shalom; Sagi, Orli; Greenberg, David

2014-04-01

Intestinal parasites cause significant morbidity worldwide, particularly in developing populations. At least three pediatric populations reside in southern Israel: the Bedouin population, the general Jewish population and Jewish children of Ethiopian origin. Our aim was to compare intestinal parasite prevalence between the three pediatric populations in southern Israel. This is a retrospective, laboratory, population-based surveillance. Most ova and parasite (O&P) tests in southern Israel (hospital and community obtained) are performed by the hospital parasitology laboratory. All pediatric stool O&P tests examined by the hospital laboratory between 2007 and 2011 were included. Overall, 45,978 samples were examined; 27,354, 16,969 and 1655 from Bedouin, non-Ethiopian Jewish and Ethiopian children, respectively. 16,317 parasites were identified in 12,325 (26.8%) positive samples. Total prevalences were 36%, 11% and 46% for Bedouin, non-Ethiopian Jewish and Ethiopian children, respectively. Blastocystis hominis, Giardia lamblia and Entamoeba species were the most common parasites identified, constituting ≥80% of positive samples in all groups. Hymenolepis nana was rarely identified in non-Ethiopian Jewish children (0.04% of isolates compared with 2.6% and 0.5% in Bedouin and Ethiopian children, respectively). Other helminths, excluding H. nana and Enterobius vermicularis, were identified almost exclusively in Ethiopian children ≥5years of age. In conclusion, the Bedouin and Ethiopian children were characterized by higher parasite prevalence in stool, compared with the non-Ethiopian Jewish children, probably reflecting higher intestinal parasitic disease rates. Certain helminthic infections were identified almost exclusively in the Ethiopian children. These differences may be associated with lifestyle differences between the three populations. © 2013.

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.

Measurement properties of performance-based outcome measures to assess physical function in young and middle-aged people known to be at high risk of hip and/or knee osteoarthritis: a systematic review.

PubMed

Kroman, S L; Roos, E M; Bennell, K L; Hinman, R S; Dobson, F

2014-01-01

To systematically appraise the evidence on measurement properties of performance-based outcome measures to assess physical function in young and middle-aged people known to be at high risk of hip and/or knee osteoarthritis (OA). Electronic searches were performed in MEDLINE, CINAHL, Scopus and SPORTDiscus in May 2013. Two reviewers independently rated the measurement properties using the 4-point COSMIN checklist. Best evidence synthesis was made using COSMIN quality, consistency and direction of findings and sample size. Twenty of 2736 papers were eligible for inclusion and 24 different performance-based outcome measures knee or obese populations were evaluated. No tests related to hip populations were included. Twenty-five measurement properties including reliability (nine studies), construct validity (hypothesis testing) (nine studies), measurement error (three studies), structural validity (two studies), interpretability (one study) and responsiveness (one study) were evaluated. A positive rating was given to 12.5% (30/240) of all possible measurement ratings. Tests were grouped into two categories based on the population characteristics. The one-legged hop for distance, followed by the 6-m timed hop and cross over hop for distance were the best-rated tests for the knee-injured population. Whereas the 6-min walk test was the only included test for the obese population. This review highlights the many gaps in knowledge about the measurement properties of performance-based outcome measures for young and middle-aged people known to be at high risk of hip and/or knee OA. There is a need for consensus on which outcome measures should be used and/or combined when assessing physical function in this population. Further good quality research is required. Copyright © 2013 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Socio-demographic predictors of sleep complaints in indigenous Siberians with a mixed economy.

PubMed

Wilson, Hannah J; Klimova, Tatiana M; Knuston, Kristen L; Fedorova, Valentina I; Fedorov, Afanasy; Yegorovna, Baltakhinova M; Leonard, William R

2015-08-01

Socio-demographic indicators closely relate to sleep in industrialized populations. However we know very little about how such factors impact sleep in populations undergoing industrialization. Within populations transitioning to the global economy, the preliminary evidence has found an inconsistent relationship between socio-demographics and sleep complaints across countries and social strata. Surveys were conducted on a sample of rural Sakha (Yakut) adults (n = 168) during the autumn of 2103 to assess variation in socio-demographics and sleep complaints, including trouble sleeping and daytime sleepiness. Socio-demographic variables included age, gender, socioeconomic measures, and markers of traditional/market-based lifestyle. We tested whether the socio-demographic variables predicted sleep complaints using bivariate analyses and multiple logistic regressions. Trouble sleeping was reported by 18.5% of the participants and excessive daytime sleepiness (EDS) by 17.3%. Trouble sleeping was significantly predicted by older age, female gender, and mixing traditional and market-based lifestyles. EDS was not significantly predicted by any socio-demographic variable. These findings support the few large-scale studies that found inconsistent relationships between measures of socioeconomic status and sleep complaints in transitioning populations. Employing a mix of traditional and market-based lifestyles may leave Sakha in a space of vulnerability, leading to trouble sleeping. © 2015 Wiley Periodicals, Inc.

CyTOF workflow: differential discovery in high-throughput high-dimensional cytometry datasets

PubMed Central

Nowicka, Malgorzata; Krieg, Carsten; Weber, Lukas M.; Hartmann, Felix J.; Guglietta, Silvia; Becher, Burkhard; Levesque, Mitchell P.; Robinson, Mark D.

2017-01-01

High dimensional mass and flow cytometry (HDCyto) experiments have become a method of choice for high throughput interrogation and characterization of cell populations.Here, we present an R-based pipeline for differential analyses of HDCyto data, largely based on Bioconductor packages. We computationally define cell populations using FlowSOM clustering, and facilitate an optional but reproducible strategy for manual merging of algorithm-generated clusters. Our workflow offers different analysis paths, including association of cell type abundance with a phenotype or changes in signaling markers within specific subpopulations, or differential analyses of aggregated signals. Importantly, the differential analyses we show are based on regression frameworks where the HDCyto data is the response; thus, we are able to model arbitrary experimental designs, such as those with batch effects, paired designs and so on. In particular, we apply generalized linear mixed models to analyses of cell population abundance or cell-population-specific analyses of signaling markers, allowing overdispersion in cell count or aggregated signals across samples to be appropriately modeled. To support the formal statistical analyses, we encourage exploratory data analysis at every step, including quality control (e.g. multi-dimensional scaling plots), reporting of clustering results (dimensionality reduction, heatmaps with dendrograms) and differential analyses (e.g. plots of aggregated signals). PMID:28663787

Intuitive statistics by 8-month-old infants

PubMed Central

Xu, Fei; Garcia, Vashti

2008-01-01

Human learners make inductive inferences based on small amounts of data: we generalize from samples to populations and vice versa. The academic discipline of statistics formalizes these intuitive statistical inferences. What is the origin of this ability? We report six experiments investigating whether 8-month-old infants are “intuitive statisticians.” Our results showed that, given a sample, the infants were able to make inferences about the population from which the sample had been drawn. Conversely, given information about the entire population of relatively small size, the infants were able to make predictions about the sample. Our findings provide evidence that infants possess a powerful mechanism for inductive learning, either using heuristics or basic principles of probability. This ability to make inferences based on samples or information about the population develops early and in the absence of schooling or explicit teaching. Human infants may be rational learners from very early in development. PMID:18378901

Characteristics of adults with anxiety or depression treated at an internet clinic: comparison with a national survey and an outpatient clinic.

PubMed

Titov, Nickolai; Andrews, Gavin; Kemp, Alice; Robinson, Emma

2010-05-28

There is concern that people seeking treatment over the Internet for anxiety or depressive disorders may not resemble the general population or have less severe disorders than patients attending outpatient clinics or cases identified in community surveys. Thus the response to treatment in Internet based trials might not generalize. We reviewed the characteristics of applicants to an Australian Internet-based treatment clinic for anxiety and depression, and compared this sample with people from a national epidemiological survey and a sample of patients at a specialist outpatient anxiety and depression clinic. Participants included 774 volunteers to an Internet clinic, 454 patients at a specialist anxiety disorders outpatient clinic, and 627 cases identified in a national epidemiological survey. Main measures included demographic characteristics, and severity of symptoms as measured by the Kessler 10-Item scale (K-10), the 12-item World Health Organisation Disability Assessment Schedule second edition (WHODAS-II), the Penn State Worry Questionnaire (PSWQ), the Body Sensations Questionnaire (BSQ), the Automatic Cognitions Questionnaire (ACQ), the Social Interaction Anxiety Scale (SIAS) and the Social Phobia Scale (SPS). The severity of symptoms of participants attending the two clinics was similar, and both clinic samples were more severe than cases in the epidemiological survey. The Internet clinic and national samples were older and comprised more females than those attending the outpatient clinic. The Internet clinic sample were more likely to be married than the other samples. The Internet clinic and outpatient clinic samples had higher levels of educational qualifications than the national sample, but employment status was similar across groups. The Internet clinic sample have disorders as severe as those attending an outpatient clinic, but with demographic characteristics more consistent with the national sample. These data indicate that the benefits of Internet treatment could apply to the wider population.

Academic Freedom in Al Al-Bayt University and the Level of Practicing It from the View Point of the Faculty Members Based on Some Variables

ERIC Educational Resources Information Center

Al-Madi, Bayan

2013-01-01

The purpose of this study is to identify the level of practicing academic freedom by the faculty members of Al al-Bayt University. The study population included all the faculty members (297) of Al al-Bayt University, during the academic year, 2010/2011. The study sample was randomly selected and included 250 faculty members. To achieve the aims of…

Collecting behavioural data using the world wide web: considerations for researchers

PubMed Central

Rhodes, S; Bowie, D; Hergenrather, K

2003-01-01

Objective: To identify and describe advantages, challenges, and ethical considerations of web based behavioural data collection. Methods: This discussion is based on the authors' experiences in survey development and study design, respondent recruitment, and internet research, and on the experiences of others as found in the literature. Results: The advantages of using the world wide web to collect behavioural data include rapid access to numerous potential respondents and previously hidden populations, respondent openness and full participation, opportunities for student research, and reduced research costs. Challenges identified include issues related to sampling and sample representativeness, competition for the attention of respondents, and potential limitations resulting from the much cited "digital divide", literacy, and disability. Ethical considerations include anonymity and privacy, providing and substantiating informed consent, and potential risks of malfeasance. Conclusions: Computer mediated communications, including electronic mail, the world wide web, and interactive programs will play an ever increasing part in the future of behavioural science research. Justifiable concerns regarding the use of the world wide web in research exist, but as access to, and use of, the internet becomes more widely and representatively distributed globally, the world wide web will become more applicable. In fact, the world wide web may be the only research tool able to reach some previously hidden population subgroups. Furthermore, many of the criticisms of online data collection are common to other survey research methodologies. PMID:12490652

Collecting behavioural data using the world wide web: considerations for researchers.

PubMed

Rhodes, S D; Bowie, D A; Hergenrather, K C

2003-01-01

To identify and describe advantages, challenges, and ethical considerations of web based behavioural data collection. This discussion is based on the authors' experiences in survey development and study design, respondent recruitment, and internet research, and on the experiences of others as found in the literature. The advantages of using the world wide web to collect behavioural data include rapid access to numerous potential respondents and previously hidden populations, respondent openness and full participation, opportunities for student research, and reduced research costs. Challenges identified include issues related to sampling and sample representativeness, competition for the attention of respondents, and potential limitations resulting from the much cited "digital divide", literacy, and disability. Ethical considerations include anonymity and privacy, providing and substantiating informed consent, and potential risks of malfeasance. Computer mediated communications, including electronic mail, the world wide web, and interactive programs will play an ever increasing part in the future of behavioural science research. Justifiable concerns regarding the use of the world wide web in research exist, but as access to, and use of, the internet becomes more widely and representatively distributed globally, the world wide web will become more applicable. In fact, the world wide web may be the only research tool able to reach some previously hidden population subgroups. Furthermore, many of the criticisms of online data collection are common to other survey research methodologies.

Cross-cultural measurement invariance of the General Health Questionnaire-12 in a German and a Colombian population sample.

PubMed

Romppel, Matthias; Hinz, Andreas; Finck, Carolyn; Young, Jeremy; Brähler, Elmar; Glaesmer, Heide

2017-12-01

While the General Health Questionnaire, 12-item version (GHQ-12) has been widely used in cross-cultural comparisons, rigorous tests of the measurement equivalence of different language versions are still lacking. Thus, our study aims at investigating configural, metric and scalar invariance across the German and the Spanish version of the GHQ-12 in two population samples. The GHQ-12 was applied in two large-scale population-based samples in Germany (N = 1,977) and Colombia (N = 1,500). To investigate measurement equivalence, confirmatory factor analyses were conducted in both samples. In the German sample mean GHQ-12 total scores were higher than in the Colombian sample. A one-factor model including response bias on the negatively worded items showed superior fit in the German and the Colombian sample; thus both versions of the GHQ-12 showed configural invariance. Factor loadings and intercepts were not equal across both samples; thus GHQ-12 showed no metric and scalar invariance. As both versions of the GHQ-12 did not show measurement equivalence, it is not recommendable to compare both measures and to conclude that mental distress is higher in the German sample, although we do not know if the differences are attributable to measurement problems or represent a real difference in mental distress. The study underlines the importance of measurement equivalence in cross-cultural comparisons. Copyright © 2017 John Wiley & Sons, Ltd.

The 25 parsec local white dwarf population

NASA Astrophysics Data System (ADS)

Holberg, J. B.; Oswalt, T. D.; Sion, E. M.; McCook, G. P.

2016-11-01

We have extended our detailed survey of the local white dwarf population from 20 to 25 pc, effectively doubling the sample volume, which now includes 232 stars. In the process, new stars within 20 pc have been added, a more uniform set of distance estimates as well as improved spectral and binary classifications are available. The present 25 pc sample is estimated to be about 68 per cent complete (the corresponding 20 pc sample is now 86 per cent complete). The space density of white dwarfs is unchanged at 4.8 ± 0.5 × 10-3 pc-3. This new study includes a white dwarf mass distribution and luminosity function based on the 232 stars in the 25 pc sample. We find a significant excess of single stars over systems containing one or more companions (74 per cent versus 26 per cent). This suggests mechanisms that result in the loss of companions during binary system evolution. In addition, this updated sample exhibits a pronounced deficiency of nearby `Sirius-like' systems. 11 such systems were found within the 20 pc volume versus only one additional system found in the volume between 20 and 25 pc. An estimate of white dwarf birth rates during the last ˜8 Gyr is derived from individual remnant cooling ages. A discussion of likely ways new members of the local sample may be found is provided.

A panel of microsatellites to individually identify leopards and its application to leopard monitoring in human dominated landscapes.

PubMed

Mondol, Samrat; Navya, R; Athreya, Vidya; Sunagar, Kartik; Selvaraj, Velu Mani; Ramakrishnan, Uma

2009-12-04

Leopards are the most widely distributed of the large cats, ranging from Africa to the Russian Far East. Because of habitat fragmentation, high human population densities and the inherent adaptability of this species, they now occupy landscapes close to human settlements. As a result, they are the most common species involved in human wildlife conflict in India, necessitating their monitoring. However, their elusive nature makes such monitoring difficult. Recent advances in DNA methods along with non-invasive sampling techniques can be used to monitor populations and individuals across large landscapes including human dominated ones. In this paper, we describe a DNA-based method for leopard individual identification where we used fecal DNA samples to obtain genetic material. Further, we apply our methods to non-invasive samples collected in a human-dominated landscape to estimate the minimum number of leopards in this human-leopard conflict area in Western India. In this study, 25 of the 29 tested cross-specific microsatellite markers showed positive amplification in 37 wild-caught leopards. These loci revealed varied levels of polymorphism (four-12 alleles) and heterozygosity (0.05-0.79). Combining data on amplification success (including non-invasive samples) and locus specific polymorphisms, we showed that eight loci provide a sibling probability of identity of 0.0005, suggesting that this panel can be used to discriminate individuals in the wild. When this microsatellite panel was applied to fecal samples collected from a human-dominated landscape, we identified 7 individuals, with a sibling probability of identity of 0.001. Amplification success of field collected scats was up to 72%, and genotype error ranged from 0-7.4%. Our results demonstrated that the selected panel of eight microsatellite loci can conclusively identify leopards from various kinds of biological samples. Our methods can be used to monitor leopards over small and large landscapes to assess population trends, as well as could be tested for population assignment in forensic applications.

A panel of microsatellites to individually identify leopards and its application to leopard monitoring in human dominated landscapes

PubMed Central

2009-01-01

Background Leopards are the most widely distributed of the large cats, ranging from Africa to the Russian Far East. Because of habitat fragmentation, high human population densities and the inherent adaptability of this species, they now occupy landscapes close to human settlements. As a result, they are the most common species involved in human wildlife conflict in India, necessitating their monitoring. However, their elusive nature makes such monitoring difficult. Recent advances in DNA methods along with non-invasive sampling techniques can be used to monitor populations and individuals across large landscapes including human dominated ones. In this paper, we describe a DNA-based method for leopard individual identification where we used fecal DNA samples to obtain genetic material. Further, we apply our methods to non-invasive samples collected in a human-dominated landscape to estimate the minimum number of leopards in this human-leopard conflict area in Western India. Results In this study, 25 of the 29 tested cross-specific microsatellite markers showed positive amplification in 37 wild-caught leopards. These loci revealed varied levels of polymorphism (four-12 alleles) and heterozygosity (0.05-0.79). Combining data on amplification success (including non-invasive samples) and locus specific polymorphisms, we showed that eight loci provide a sibling probability of identity of 0.0005, suggesting that this panel can be used to discriminate individuals in the wild. When this microsatellite panel was applied to fecal samples collected from a human-dominated landscape, we identified 7 individuals, with a sibling probability of identity of 0.001. Amplification success of field collected scats was up to 72%, and genotype error ranged from 0-7.4%. Conclusion Our results demonstrated that the selected panel of eight microsatellite loci can conclusively identify leopards from various kinds of biological samples. Our methods can be used to monitor leopards over small and large landscapes to assess population trends, as well as could be tested for population assignment in forensic applications. PMID:19961605

Evolutionary history of Ichthyosaura alpestris (Caudata, Salamandridae) inferred from the combined analysis of nuclear and mitochondrial markers.

PubMed

Recuero, Ernesto; Buckley, David; García-París, Mario; Arntzen, Jan W; Cogălniceanu, Dan; Martínez-Solano, Iñigo

2014-12-01

Widespread species with morphologically and ecologically differentiated populations are key to understand speciation because they allow investigating the different stages of the continuous process of population divergence. The alpine newt, Ichthyosaura alpestris, with a range that covers a large part of Central Europe as well as isolated regions in all three European Mediterranean peninsulas, and with strong ecological and life-history differences among populations, is an excellent system for such studies. We sampled individuals across most of the range of the species, and analyzed mitochondrial (1442 bp) and nuclear (two nuclear genes -1554 bp- and 35 allozyme loci) markers to produce a time-calibrated phylogeny and reconstruct the historical biogeography of the species. Phylogenetic analyses of mtDNA data produced a fully resolved topology, with an endemic, Balkan clade (Vlasina) which is sister to a clade comprising an eastern and a western group. Within the former, one clade (subspecies I. a. veluchiensis) is sister to a clade containing subspecies I. a. montenegrina and I. a. serdara as well as samples from southern Romania, Bosnia-Herzegovina, Serbia and Bulgaria (subspecies I. a. reiseri and part of I. a. alpestris). Within the western group, populations from the Italian peninsula (subspecies I. a. apuana and I. a. inexpectata) are sister to a clade containing samples from the Iberian Peninsula (subspecies I. a. cyreni) and the remainder of the samples from subspecies I. a. alpestris (populations from Hungary, Austria, Poland, France, Germany and the larger part of Romania). Results of (∗)BEAST analyses on a combined mtDNA and nDNA dataset consistently recovered with high statistical support four lineages with unresolved inter-relationships: (1) subspecies I. a. veluchiensis; (2) subspecies I. a. apuana+I. a. inexpectata; (3) subspecies I. a. cyreni+part of subspecies I. a. alpestris (the westernmost populations, plus most Romanian populations); and (4) the remaining populations, including subspecies I. a. serdara, I. a. reiseri and I. a. montenegrina and part of subspecies I. a. alpestris, plus samples from Vlasina. Our time estimates are consistent with ages based on the fossil record and suggest a widespread distribution for the I. alpestris ancestor, with the split of the major eastern and western lineages during the Miocene, in the Tortonian. Our study provides a solid, comprehensive background on the evolutionary history of the species based on the most complete combined (mtDNA+nDNA+allozymes) dataset to date. The combination of the historical perspective provided by coalescent-based analyses of mitochondrial and nuclear DNA variation with individual-based multilocus assignment methods based on multiple nuclear markers (allozymes) also allowed identification of instances of discordance across markers that highlight the complexity and dynamism of past and ongoing evolutionary processes in the species. Copyright © 2014 Elsevier Inc. All rights reserved.

Reproductive health surveillance in the US-Mexico border region, 2003-2006: the Brownsville-Matamoros Sister City Project for Women's Health.

PubMed

McDonald, Jill A; Johnson, Christopher H; Smith, Ruben; Folger, Suzanne G; Chavez, Ana L; Mishra, Ninad; Hernández Jiménez, Antonio; MacDonald, Linda R; Hernández Rodríguez, Jorge Sebastián; Villalobos, Susie Ann

2008-10-01

High birth and immigration rates in the US-Mexico border region have led to large population increases in recent decades. Two national, 10 state, and more than 100 local government entities deliver reproductive health services to the region's 14 million residents. Limited standardized information about health risks in this population hampers capacity to address local needs and assess effectiveness of public health programs. We worked with binational partners to develop a system for reproductive health surveillance in the sister communities of Matamoros, Tamaulipas, Mexico, and Cameron County, Texas, as a model for a broader regional approach. We used a stratified, systematic cluster-sampling design to sample women giving birth in hospitals in each community during an 81-day period (August 21-November 9) in 2005. We conducted in-hospital computer-assisted personal interviews that addressed prenatal, behavioral, and lifestyle factors. We evaluated survey response rates, data quality, and other attributes of effective surveillance systems. We estimated population coverage using vital records data. Among the 999 women sampled, 947 (95%) completed interviews, and the item nonresponse rate was low. The study sample included 92.7% of live births in Matamoros and 98.3% in Cameron County. Differences between percentage distributions of birth certificate characteristics in the study and target populations did not exceed 2.0. Study population coverage among hospitals ranged from 92.9% to 100.0%, averaging 97.3% in Matamoros and 97.4% in Cameron County. Results indicate that hospital-based sampling and postpartum interviewing constitute an effective approach to reproductive health surveillance. Such a system can yield valuable information for public health programs serving the growing US-Mexico border population.

Effect of on-site wastewater disposal on quality of ground water and base flow: A pilot study in Chester County, Southeastern Pennsylvania, 2005

USGS Publications Warehouse

Senior, Lisa A.; Cinotto, Peter J.

2007-01-01

On-site wastewater disposal has the potential to introduce contaminants into ground water and subsequently, by ground-water discharge, to streams. A pilot study was conducted during 2005 by the U.S. Geological Survey in cooperation with the Chester County Health Department and the Chester County Water Resources Authority to determine if wastewater components, including inorganic constituents and selected organic wastewater compounds, such as detergents, considered to be emerging contaminants, were present in ground water and stream base flow in areas with on-site wastewater disposal. The study area was a small watershed (about 7.1 square miles) of mixed land use drained by Broad Run in central Chester County, Pa. The area is underlain by fractured metamorphic rocks that form aquifers recharged by precipitation. Surface- and ground-water sampling was done in areas with and without on-site wastewater disposal for comparison, including a relatively densely populated village with cesspools and septic systems, a residential area with septic systems, a residential area served by sewers, and agricultural land. Samples were collected in May-June and September 2005 from eight headwater stream sites under base-flow conditions and in June 2005 from eight wells and two springs. Samples were analyzed for major ions, nutrients, boron, bacteria, and a suite of organic wastewater compounds. Several emerging contaminant wastewater compounds, including detergent components, insect repellents, and flame retardants, were detected in base-flow and ground-water samples. Stream base-flow samples generally contained more compounds and higher concentrations of those compounds than did ground-water samples, and of the ground-water samples, samples from springs contained more compounds and higher concentrations than samples from wells. Concentrations of nitrate, chloride, and boron (inorganic constituents associated with wastewater) generally were all elevated in base-flow and ground-water samples in areas with relatively high densities of on-site wastewater disposal (septic systems or cesspools) compared to other areas sampled. Results of this pilot study should be considered preliminary because of limited data.

Evidence for population bottlenecks and subtle genetic structure in the yellow rail

USGS Publications Warehouse

Popper, Kenneth J.; Miller, Leonard F.; Green, Michael; Haig, Susan M.; Mullins, Thomas D.

2012-01-01

The Yellow Rail (Coturnicops noveboracencis) is among the most enigmatic and least studied North American birds. Nesting exclusively in marshes and wetlands, it breeds largely east of the Rocky Mountains in the northern United States and Canada, but there is an isolated population in southern Oregon once believed extirpated. The degree of connectivity of the Oregon population with the main population is unknown. We used mitochondrial DNA sequences (mtDNA) and six microsatellite loci to characterize the Yellow Rail's genetic structure and diversity patterns in six areas. Our mtDNA-based analyses of genetic structure identified significant population differentiation, but pairwise comparison of regions identified no clear geographic trends. In contrast, microsatellites suggested subtle genetic structure differentiating the Oregon population from those in the five regions sampled in the Yellow Rail's main breeding range. The genetic diversity of the Oregon population was also the lowest of the six regions sampled, and Oregon was one of three regions that demonstrated evidence of recent population bottlenecks. Factors that produced population reductions may include loss of wetlands to development and agricultural conversion, drought, and wildfire. At this time, we are unable to determine if the high percentage (50%) of populations having experienced bottlenecks is representative of the Yellow Rail's entire range. Further genetic data from additional breeding populations will be required for this issue to be addressed.

Estimation of mortality for stage-structured zooplankton populations: What is to be done?

NASA Astrophysics Data System (ADS)

Ohman, Mark D.

2012-05-01

Estimation of zooplankton mortality rates in field populations is a challenging task that some contend is inherently intractable. This paper examines several of the objections that are commonly raised to efforts to estimate mortality. We find that there are circumstances in the field where it is possible to sequentially sample the same population and to resolve biologically caused mortality, albeit with error. Precision can be improved with sampling directed by knowledge of the physical structure of the water column, combined with adequate sample replication. Intercalibration of sampling methods can make it possible to sample across the life history in a quantitative manner. Rates of development can be constrained by laboratory-based estimates of stage durations from temperature- and food-dependent functions, mesocosm studies of molting rates, or approximation of development rates from growth rates, combined with the vertical distributions of organisms in relation to food and temperature gradients. Careful design of field studies guided by the assumptions of specific estimation models can lead to satisfactory mortality estimates, but model uncertainty also needs to be quantified. We highlight additional issues requiring attention to further advance the field, including the need for linked cooperative studies of the rates and causes of mortality of co-occurring holozooplankton and ichthyoplankton.

Rationale and Methodology for a Community-Based Study of Diabetic Retinopathy in an Indonesian Population with Type 2 Diabetes Mellitus: The Jogjakarta Eye Diabetic Study in the Community.

PubMed

Sasongko, Muhammad B; Agni, Angela N; Wardhana, Firman S; Kotha, Satya P; Gupta, Prateek; Widayanti, Tri W; Supanji; Widyaputri, Felicia; Widyaningrum, Rifa; Wong, Tien Y; Kawasaki, Ryo; Wang, Jie Jin; Pawiroranu, Suhardjo

2017-02-01

There are no available data about diabetic retinopathy (DR) in the Indonesian population. This report summarizes the rationale and study design of the Jogjakarta Eye Diabetic Study in the Community (JOGED.COM), a community-based study to estimate the prevalence and risk factors of DR in persons with type 2 diabetes in Jogjakarta, Indonesia. The JOGED.COM aimed to examine a cross-sectional sample of 1200 persons with type 2 diabetes aged 30 years and older residing in the study area. We identified 121 community health centers (CHCs) in Jogjakarta and listed 35 CHCs with non-communicable diseases facilities. Multi-stage, clustered random sampling was used to select 22 CHCs randomly. We included CHCs with coverage population >30,000, and excluded those classified as 100% rural. Lists of persons with diabetes confirmed by their family physician were provided from each CHC. Examinations procedures included detailed interviews, general and eye examinations, anthropometry and body composition scan, and dilated fundus photography. We collaborated with local health authorities, family physicians, and local health practitioners in the recruitment phase. A total of 1435 invitations were distributed, and 1184 people (82.5%) with type 2 diabetes participated in this study, of whom 1138 (79.3%) had completed data with gradable retinal images. JOGED.COM is the first epidemiologic study of DR in an Indonesian population. This study will provide key information about the prevalence and risk factors of DR in the community. These data are very important for future health promotion programs to reduce the burden of DR in the population.

Correction of Population Stratification in Large Multi-Ethnic Association Studies

PubMed Central

Serre, David; Montpetit, Alexandre; Paré, Guillaume; Engert, James C.; Yusuf, Salim; Keavney, Bernard; Hudson, Thomas J.; Anand, Sonia

2008-01-01

Background The vast majority of genetic risk factors for complex diseases have, taken individually, a small effect on the end phenotype. Population-based association studies therefore need very large sample sizes to detect significant differences between affected and non-affected individuals. Including thousands of affected individuals in a study requires recruitment in numerous centers, possibly from different geographic regions. Unfortunately such a recruitment strategy is likely to complicate the study design and to generate concerns regarding population stratification. Methodology/Principal Findings We analyzed 9,751 individuals representing three main ethnic groups - Europeans, Arabs and South Asians - that had been enrolled from 154 centers involving 52 countries for a global case/control study of acute myocardial infarction. All individuals were genotyped at 103 candidate genes using 1,536 SNPs selected with a tagging strategy that captures most of the genetic diversity in different populations. We show that relying solely on self-reported ethnicity is not sufficient to exclude population stratification and we present additional methods to identify and correct for stratification. Conclusions/Significance Our results highlight the importance of carefully addressing population stratification and of carefully “cleaning” the sample prior to analyses to obtain stronger signals of association and to avoid spurious results. PMID:18196181

Facebook Ads Recruit Parents of Children with Cancer for an Online Survey of Web-Based Research Preferences

PubMed Central

Akard, Terrah Foster; Wray, Sarah; Gilmer, Mary

2014-01-01

Background Studies involving samples of children with life-threatening illnesses and their families face significant challenges, including inadequate sample sizes and limited diversity. Social media recruitment and web-based research methods may help address such challenges yet have not been explored in pediatric cancer populations. Objective This study examined the feasibility of using Facebook ads to recruit parent caregivers of children and teens with cancer. We also explored the feasibility of web-based video recording in pediatric palliative care populations by surveying parents of children with cancer regarding (a) their preferences for research methods and (b) technological capabilities of their computers and phones. Methods Facebook's paid advertising program was used to recruit parent caregivers of children currently living with cancer to complete an electronic survey about research preferences and technological capabilities. Results The advertising campaign generated 3,897,981 impressions which resulted in 1050 clicks at a total cost of $1129.88. Of 284 screened individuals, 106 were eligible. Forty-five caregivers of children with cancer completed the entire electronic survey. Parents preferred and had technological capabilities for web-based and electronic research methods. Participant survey responses are reported. Conclusion Facebook was a useful, cost-effective method to recruit a diverse sample of parent caregivers of children with cancer. Web-based video recording and data collection may be feasible and desirable in samples of children with cancer and their families. Implications for Practice Web-based methods (e.g., Facebook, Skype) may enhance communication and access between nurses and pediatric oncology patients and their families. PMID:24945264

Microbial community dynamics of an urban drinking water distribution system subjected to phases of chloramination and chlorination treatments.

PubMed

Hwang, Chiachi; Ling, Fangqiong; Andersen, Gary L; LeChevallier, Mark W; Liu, Wen-Tso

2012-11-01

Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (<21.2 h) had no apparent effects on the microbial compositions of samples from most time points. Microbial community analysis revealed that among major core populations, Cyanobacteria, Methylobacteriaceae, Sphingomonadaceae, and Xanthomonadaceae were more abundant in chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (<0.1% of total pyrosequences), which were likely present in source water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine.

Microbial Community Dynamics of an Urban Drinking Water Distribution System Subjected to Phases of Chloramination and Chlorination Treatments

PubMed Central

Hwang, Chiachi; Ling, Fangqiong; Andersen, Gary L.; LeChevallier, Mark W.

2012-01-01

Water utilities in parts of the U.S. control microbial regrowth in drinking water distribution systems (DWDS) by alternating postdisinfection methods between chlorination and chloramination. To examine how this strategy influences drinking water microbial communities, an urban DWDS (population ≅ 40,000) with groundwater as the source water was studied for approximately 2 years. Water samples were collected at five locations in the network at different seasons and analyzed for their chemical and physical characteristics and for their microbial community composition and structure by examining the 16S rRNA gene via terminal restriction fragment length polymorphism and DNA pyrosequencing technology. Nonmetric multidimension scaling and canonical correspondence analysis of microbial community profiles could explain >57% of the variation. Clustering of samples based on disinfection types (free chlorine versus combined chlorine) and sampling time was observed to correlate to the shifts in microbial communities. Sampling location and water age (<21.2 h) had no apparent effects on the microbial compositions of samples from most time points. Microbial community analysis revealed that among major core populations, Cyanobacteria, Methylobacteriaceae, Sphingomonadaceae, and Xanthomonadaceae were more abundant in chlorinated water, and Methylophilaceae, Methylococcaceae, and Pseudomonadaceae were more abundant in chloraminated water. No correlation was observed with minor populations that were detected frequently (<0.1% of total pyrosequences), which were likely present in source water and survived through the treatment process. Transient microbial populations including Flavobacteriaceae and Clostridiaceae were also observed. Overall, reversible shifts in microbial communities were especially pronounced with chloramination, suggesting stronger selection of microbial populations from chloramines than chlorine. PMID:22941076

Sexual Orientation and School Discipline: New Evidence from a Population-Based Sample

ERIC Educational Resources Information Center

Mittleman, Joel

2018-01-01

Sexual minorities' risk for exclusionary discipline is a commonly cited indicator of the challenges that these students face. The current study addresses this issue by introducing a new data source for research on sexual minority students: the Fragile Families and Childhood Wellbeing Study. In this geographically diverse, population-based sample,…

The prevalence of ADHD in a population-based sample

PubMed Central

Rowland, Andrew S.; Skipper, Betty J.; Umbach, David M.; Rabiner, David L.; Campbell, Richard A.; Naftel, A. Jack; Sandler, Dale P.

2014-01-01

Objective Few studies of ADHD prevalence have used population-based samples, multiple informants, and DSM-IV criteria. In addition, children who are asymptomatic while receiving ADHD mediction often have been misclassified. Therefore, we conducted a population-based study to estimate the prevalence of ADHD in elementary school children using DSM-IV critera. Methods We screened 7587 children for ADHD. Teachers of 81% of the children completed a DSM-IV checklist. We then interviewed parents using a structured interview (DISC). Of these, 72% participated. Parent and teacher ratings were combined to determine ADHD status. We also estimated the proportion of cases attributable to other conditions. Results Overall, 15.5% of our sample (95% confidence interval (C.I.) 14.6%-16.4%) met DSM-IV-TR criteria for ADHD. Over 40% of cases reported no previous diagnosis. With additional information, other conditions explained about 9% of cases. Conclusions The prevalence of ADHD in this population-based sample was higher than the 3-7% commonly reported. To compare study results, the methods used to implement the DSM criteria need to be standardized. PMID:24336124

Adaptive sampling in research on risk-related behaviors.

PubMed

Thompson, Steven K; Collins, Linda M

2002-11-01

This article introduces adaptive sampling designs to substance use researchers. Adaptive sampling is particularly useful when the population of interest is rare, unevenly distributed, hidden, or hard to reach. Examples of such populations are injection drug users, individuals at high risk for HIV/AIDS, and young adolescents who are nicotine dependent. In conventional sampling, the sampling design is based entirely on a priori information, and is fixed before the study begins. By contrast, in adaptive sampling, the sampling design adapts based on observations made during the survey; for example, drug users may be asked to refer other drug users to the researcher. In the present article several adaptive sampling designs are discussed. Link-tracing designs such as snowball sampling, random walk methods, and network sampling are described, along with adaptive allocation and adaptive cluster sampling. It is stressed that special estimation procedures taking the sampling design into account are needed when adaptive sampling has been used. These procedures yield estimates that are considerably better than conventional estimates. For rare and clustered populations adaptive designs can give substantial gains in efficiency over conventional designs, and for hidden populations link-tracing and other adaptive procedures may provide the only practical way to obtain a sample large enough for the study objectives.

How have researchers studied multiracial populations? A content and methodological review of 20 years of research.

PubMed

Charmaraman, Linda; Woo, Meghan; Quach, Ashley; Erkut, Sumru

2014-07-01

The U.S. Census shows that the racial-ethnic makeup of over 9 million people (2.9% of the total population) who self-identified as multiracial is extremely diverse. Each multiracial subgroup has unique social and political histories that may lead to distinct societal perceptions, economic situations, and health outcomes. Despite the increasing academic and media interest in multiracial individuals, there are methodological and definitional challenges in studying the population, resulting in conflicting representations in the literature. This content and methods review of articles on multiracial populations provides a comprehensive understanding of which multiracial populations have been included in research and how they have been studied, both to recognize emerging research and to identify gaps for guiding future research on this complex but increasingly visible population. We examine 125 U.S.-based peer-reviewed journal articles published over the past 20 years (1990 to 2009) containing 133 separate studies focused on multiracial individuals, primarily from the fields of psychology, sociology, social work, education, and public health. Findings include (a) descriptive data regarding the sampling strategies, methodologies, and demographic characteristics of studies, including which multiracial subgroups are most studied, gender, age range, region of country, and socioeconomic status; (b) major thematic trends in research topics concerning multiracial populations; and (c) implications and recommendations for future studies.

Medical Decision-Making for Adults Who Lack Decision-Making Capacity and a Surrogate: State of the Science.

PubMed

Kim, Hyejin; Song, Mi-Kyung

2018-01-01

Adults who lack decision-making capacity and a surrogate ("unbefriended" adults) are a vulnerable, voiceless population in health care. But little is known about this population, including how medical decisions are made for these individuals. This integrative review was to examine what is known about unbefriended adults and identify gaps in the literature. Six electronic databases were searched using 4 keywords: "unbefriended," "unrepresented patients," "adult orphans," and "incapacitated patients without surrogates." After screening, the final sample included 10 data-based articles for synthesis. Main findings include the following: (1) various terms were used to refer to adults who lack decision-making capacity and a surrogate; (2) the number of unbefriended adults was sizable and likely to grow; (3) approaches to medical decision-making for this population in health-care settings varied; and (4) professional guidelines and laws to address the issues related to this population were inconsistent. There have been no studies regarding the quality of medical decision-making and its outcomes for this population or societal impact. Extremely limited empirical data exist on unbefriended adults to develop strategies to improve how medical decisions are made for this population. There is an urgent need for research to examine the quality of medical decision-making and its outcomes for this vulnerable population.

Labor Force Participation Rates among Working-Age Individuals with Visual Impairments

ERIC Educational Resources Information Center

Kelly, Stacy M.

2013-01-01

The present study analyzes four consecutive years of monthly labor force participation rates reported by the Current Population Survey that included nationally representative samples of the general U.S. population and nationally representative samples of the U.S. population with specifically identified disabilities. Visual impairment is one of the…

The Genome Austria Tissue Bank (GATiB).

PubMed

Asslaber, M; Abuja, P M; Stark, K; Eder, J; Gottweis, H; Trauner, M; Samonigg, H; Mischinger, H J; Schippinger, W; Berghold, A; Denk, H; Zatloukal, K

2007-01-01

In the context of the Austrian Genome Program, a tissue bank is being established (Genome Austria Tissue Bank, GATiB) which is based on a collection of diseased and corresponding normal tissues representing a great variety of diseases at their natural frequency of occurrence from a non-selected Central European population of more than 700,000 patients. Major emphasis is put on annotation of archival tissue with comprehensive clinical data, including follow-up data. A specific IT infrastructure supports sample annotation, tracking of sample usage as well as sample and data storage. Innovative data protection tools were developed which prevent sample donor re-identification, particularly if detailed medical and genetic data are combined. For quality control of old archival tissues, new techniques were established to check RNA quality and antigen stability. Since 2003, GATiB has changed from a population-based tissue bank to a disease-focused biobank comprising major cancers such as colon, breast, liver, as well as metabolic liver diseases and organs affected by the metabolic syndrome. Prospectively collected tissues are associated with blood samples and detailed data on the sample donor's disease, lifestyle and environmental exposure, following standard operating procedures. Major emphasis is also placed on ethical, legal and social issues (ELSI) related to biobanks. A specific research project and an international advisory board ensure the proper embedding of GATiB in society and facilitate international networking. (c) 2007 S. Karger AG, Basel.

Differential expression analysis for RNAseq using Poisson mixed models.

PubMed

Sun, Shiquan; Hood, Michelle; Scott, Laura; Peng, Qinke; Mukherjee, Sayan; Tung, Jenny; Zhou, Xiang

2017-06-20

Identifying differentially expressed (DE) genes from RNA sequencing (RNAseq) studies is among the most common analyses in genomics. However, RNAseq DE analysis presents several statistical and computational challenges, including over-dispersed read counts and, in some settings, sample non-independence. Previous count-based methods rely on simple hierarchical Poisson models (e.g. negative binomial) to model independent over-dispersion, but do not account for sample non-independence due to relatedness, population structure and/or hidden confounders. Here, we present a Poisson mixed model with two random effects terms that account for both independent over-dispersion and sample non-independence. We also develop a scalable sampling-based inference algorithm using a latent variable representation of the Poisson distribution. With simulations, we show that our method properly controls for type I error and is generally more powerful than other widely used approaches, except in small samples (n <15) with other unfavorable properties (e.g. small effect sizes). We also apply our method to three real datasets that contain related individuals, population stratification or hidden confounders. Our results show that our method increases power in all three data compared to other approaches, though the power gain is smallest in the smallest sample (n = 6). Our method is implemented in MACAU, freely available at www.xzlab.org/software.html. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

[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.

The Distribution of and Factors Associated with Intimate Terrorism and Situational Couple Violence among a Population-Based Sample of Urban Women in the United States

ERIC Educational Resources Information Center

Frye, Victoria; Manganello, Jennifer; Campbell, Jacquelyn C.; Walton-Moss, Benita; Wilt, Susan

2006-01-01

It has been proposed that two distinct forms of intimate partner violence exist: intimate terrorism and situational couple violence. This article describes the distribution of factors that characterize intimate terrorism and situational couple violence, including controlling behaviors, violence escalation, and injury, among a representative sample…

The Impact of Attention-Deficit/Hyperactivity Disorder on Preadolescent Adjustment May Be Greater for Girls than for Boys

ERIC Educational Resources Information Center

Elkins, Irene J.; Malone, Steve; Keyes, Margaret; Iacono, William G.; McGue, Matt

2011-01-01

Whether gender differences exist in the impairment associated with attention-deficit/hyperactivity disorder (ADHD) is still largely unknown, because most samples have few affected girls or include only one sex. The current study evaluated whether ADHD affects adjustment differently for girls than boys in a population-based cohort of 11-year-olds…

The iPSYCH2012 case–cohort sample: new directions for unravelling genetic and environmental architectures of severe mental disorders

PubMed Central

Pedersen, C B; Bybjerg-Grauholm, J; Pedersen, M G; Grove, J; Agerbo, E; Bækvad-Hansen, M; Poulsen, J B; Hansen, C S; McGrath, J J; Als, T D; Goldstein, J I; Neale, B M; Daly, M J; Hougaard, D M; Mors, O; Nordentoft, M; Børglum, A D; Werge, T; Mortensen, P B

2018-01-01

The Integrative Psychiatric Research (iPSYCH) consortium has established a large Danish population-based Case–Cohort sample (iPSYCH2012) aimed at unravelling the genetic and environmental architecture of severe mental disorders. The iPSYCH2012 sample is nested within the entire Danish population born between 1981 and 2005, including 1 472 762 persons. This paper introduces the iPSYCH2012 sample and outlines key future research directions. Cases were identified as persons with schizophrenia (N=3540), autism (N=16 146), attention-deficit/hyperactivity disorder (N=18 726) and affective disorder (N=26 380), of which 1928 had bipolar affective disorder. Controls were randomly sampled individuals (N=30 000). Within the sample of 86 189 individuals, a total of 57 377 individuals had at least one major mental disorder. DNA was extracted from the neonatal dried blood spot samples obtained from the Danish Neonatal Screening Biobank and genotyped using the Illumina PsychChip. Genotyping was successful for 90% of the sample. The assessments of exome sequencing, methylation profiling, metabolome profiling, vitamin-D, inflammatory and neurotrophic factors are in progress. For each individual, the iPSYCH2012 sample also includes longitudinal information on health, prescribed medicine, social and socioeconomic information, and analogous information among relatives. To the best of our knowledge, the iPSYCH2012 sample is the largest and most comprehensive data source for the combined study of genetic and environmental aetiologies of severe mental disorders. PMID:28924187

What is a representative brain? Neuroscience meets population science.

PubMed

Falk, Emily B; Hyde, Luke W; Mitchell, Colter; Faul, Jessica; Gonzalez, Richard; Heitzeg, Mary M; Keating, Daniel P; Langa, Kenneth M; Martz, Meghan E; Maslowsky, Julie; Morrison, Frederick J; Noll, Douglas C; Patrick, Megan E; Pfeffer, Fabian T; Reuter-Lorenz, Patricia A; Thomason, Moriah E; Davis-Kean, Pamela; Monk, Christopher S; Schulenberg, John

2013-10-29

The last decades of neuroscience research have produced immense progress in the methods available to understand brain structure and function. Social, cognitive, clinical, affective, economic, communication, and developmental neurosciences have begun to map the relationships between neuro-psychological processes and behavioral outcomes, yielding a new understanding of human behavior and promising interventions. However, a limitation of this fast moving research is that most findings are based on small samples of convenience. Furthermore, our understanding of individual differences may be distorted by unrepresentative samples, undermining findings regarding brain-behavior mechanisms. These limitations are issues that social demographers, epidemiologists, and other population scientists have tackled, with solutions that can be applied to neuroscience. By contrast, nearly all social science disciplines, including social demography, sociology, political science, economics, communication science, and psychology, make assumptions about processes that involve the brain, but have incorporated neural measures to differing, and often limited, degrees; many still treat the brain as a black box. In this article, we describe and promote a perspective--population neuroscience--that leverages interdisciplinary expertise to (i) emphasize the importance of sampling to more clearly define the relevant populations and sampling strategies needed when using neuroscience methods to address such questions; and (ii) deepen understanding of mechanisms within population science by providing insight regarding underlying neural mechanisms. Doing so will increase our confidence in the generalizability of the findings. We provide examples to illustrate the population neuroscience approach for specific types of research questions and discuss the potential for theoretical and applied advances from this approach across areas.

What is a representative brain? Neuroscience meets population science

PubMed Central

Falk, Emily B.; Hyde, Luke W.; Mitchell, Colter; Faul, Jessica; Gonzalez, Richard; Heitzeg, Mary M.; Keating, Daniel P.; Langa, Kenneth M.; Martz, Meghan E.; Maslowsky, Julie; Morrison, Frederick J.; Noll, Douglas C.; Patrick, Megan E.; Pfeffer, Fabian T.; Reuter-Lorenz, Patricia A.; Thomason, Moriah E.; Davis-Kean, Pamela; Monk, Christopher S.; Schulenberg, John

2013-01-01

The last decades of neuroscience research have produced immense progress in the methods available to understand brain structure and function. Social, cognitive, clinical, affective, economic, communication, and developmental neurosciences have begun to map the relationships between neuro-psychological processes and behavioral outcomes, yielding a new understanding of human behavior and promising interventions. However, a limitation of this fast moving research is that most findings are based on small samples of convenience. Furthermore, our understanding of individual differences may be distorted by unrepresentative samples, undermining findings regarding brain–behavior mechanisms. These limitations are issues that social demographers, epidemiologists, and other population scientists have tackled, with solutions that can be applied to neuroscience. By contrast, nearly all social science disciplines, including social demography, sociology, political science, economics, communication science, and psychology, make assumptions about processes that involve the brain, but have incorporated neural measures to differing, and often limited, degrees; many still treat the brain as a black box. In this article, we describe and promote a perspective—population neuroscience—that leverages interdisciplinary expertise to (i) emphasize the importance of sampling to more clearly define the relevant populations and sampling strategies needed when using neuroscience methods to address such questions; and (ii) deepen understanding of mechanisms within population science by providing insight regarding underlying neural mechanisms. Doing so will increase our confidence in the generalizability of the findings. We provide examples to illustrate the population neuroscience approach for specific types of research questions and discuss the potential for theoretical and applied advances from this approach across areas. PMID:24151336

Evaluation of an osteoporosis and fall risk intervention program for community-dwelling elderly. A quasi-experimental study of behavioral modifications.

PubMed

Grahn Kronhed, Ann-Charlotte; Blomberg, Carina; Löfman, Owe; Timpka, Toomas; Möller, Margareta

2006-06-01

Osteoporosis and fall fractures are increasing problems amongst the elderly. The aim of this study was to explore whether combined population-based and individual interventions directed at risk factors for osteoporosis and falls result in behavioral changes in an elderly population. A quasi-experimental design was used for the study. Persons aged >or=65 years were randomly selected in the intervention and control community. An intervention program was managed from the primary health care center and delivered to the community. Health education was designed to increase awareness of risk factors for the development of osteoporosis and falling. Questionnaires about lifestyle, health, previous fractures, safety behavior and physical activity level were distributed at baseline in 1989 and at the follow-ups in 1992 and 1994 in both communities. There was a difference of 17.7% between the dual intervention (receiving both population-based and individual interventions) and the control samples regarding the self-reported use of shoe/cane spikes, and a difference of 20.5% regarding the reported "moderate level" of physical activity in 1994. There was an increase in the number of participants in the dual intervention sample who, at baseline, had not reported equipping their homes with non-slip mats and removing loose rugs but who did report these changes in 1994. The increase in the reported use of shoe/cane spikes in the dual intervention sample was observed mainly for the period 1992-1994. A public health intervention model, including both population-based and individual interventions, can contribute to behavioral changes in the prevention of falls and changed physical activity patterns amongst elderly people.

Which Sámi? Sámi inclusion criteria in population-based studies of Sámi health and living conditions in Norway – an exploratory study exemplified with data from the SAMINOR study

PubMed Central

Pettersen, Torunn; Brustad, Magritt

2013-01-01

Background In a situation where national censuses do not record information on ethnicity, studies of the indigenous Sámi people's health and living conditions tend to use varying Sámi inclusion criteria and categorizations. Consequently, the basis on which Sámi study participants are included and categorized when Sámi health and living conditions are explored and compared differs. This may influence the results and conclusions drawn. Objective To explore some numerical consequences of applying principles derived from Norway's Sámi Act as a foundation for formalized inclusion criteria in population-based Sámi studies in Norway. Design We established 1 geographically based (G1) and 3 individual-based Sámi example populations (I1–I3) by applying diverse Sámi inclusion criteria to data from 17 rural municipalities in Norway north of the Arctic Circle. The data were collected for a population-based study of health and living conditions in 2003–2004 (the SAMINOR study). Our sample consisted of 14,797 participants aged 36–79 years. Results The size of the individual-based populations varied significantly. I1 (linguistic connection Sámi) made up 35.5% of the sample, I2 (self-identified Sámi) made up 21.0% and I3 (active language Sámi) 17.7%. They were also noticeably unevenly distributed between the 5 Sámi regions defined for this study. The differences for the other characteristics studied were more ambiguous. For the population G1 (residents in the Sámi language area) the only significant difference found between the Sámi and the corresponding non-Sámi population was for household income (OR=0.69, 95% CI: 0.63–0.74). For the populations I1–I3 there were significant differences on all measures except for I2 and education (OR=1.09, 95% CI: 0.99–1.21). Conclusions The choice of Sámi inclusion criterion had a clear impact on the size and geographical distribution of the defined populations but lesser influence on the selected characteristics for the Sámi populations relative to the respective non-Sámi ones. PMID:24282785

Japanese population structure, based on SNP genotypes from 7003 individuals compared to other ethnic groups: effects on population-based association studies.

PubMed

Yamaguchi-Kabata, Yumi; Nakazono, Kazuyuki; Takahashi, Atsushi; Saito, Susumu; Hosono, Naoya; Kubo, Michiaki; Nakamura, Yusuke; Kamatani, Naoyuki

2008-10-01

Because population stratification can cause spurious associations in case-control studies, understanding the population structure is important. Here, we examined Japanese population structure by "Eigenanalysis," using the genotypes for 140,387 SNPs in 7003 Japanese individuals, along with 60 European, 60 African, and 90 East-Asian individuals, in the HapMap project. Most Japanese individuals fell into two main clusters, Hondo and Ryukyu; the Hondo cluster includes most of the individuals from the main islands in Japan, and the Ryukyu cluster includes most of the individuals from Okinawa. The SNPs with the greatest frequency differences between the Hondo and Ryukyu clusters were found in the HLA region in chromosome 6. The nonsynonymous SNPs with the greatest frequency differences between the Hondo and Ryukyu clusters were the Val/Ala polymorphism (rs3827760) in the EDAR gene, associated with hair thickness, and the Gly/Ala polymorphism (rs17822931) in the ABCC11 gene, associated with ear-wax type. Genetic differentiation was observed, even among different regions in Honshu Island, the largest island of Japan. Simulation studies showed that the inclusion of different proportions of individuals from different regions of Japan in case and control groups can lead to an inflated rate of false-positive results when the sample sizes are large.

MaCH-Admix: Genotype Imputation for Admixed Populations

PubMed Central

Liu, Eric Yi; Li, Mingyao; Wang, Wei; Li, Yun

2012-01-01

Imputation in admixed populations is an important problem but challenging due to the complex linkage disequilibrium (LD) pattern. The emergence of large reference panels such as that from the 1,000 Genomes Project enables more accurate imputation in general, and in particular for admixed populations and for uncommon variants. To efficiently benefit from these large reference panels, one key issue to consider in modern genotype imputation framework is the selection of effective reference panels. In this work, we consider a number of methods for effective reference panel construction inside a hidden Markov model and specific to each target individual. These methods fall into two categories: identity-by-state (IBS) based and ancestry-weighted approach. We evaluated the performance on individuals from recently admixed populations. Our target samples include 8,421 African Americans and 3,587 Hispanic Americans from the Women’s Health Initiative, which allow assessment of imputation quality for uncommon variants. Our experiments include both large and small reference panels; large, medium, and small target samples; and in genome regions of varying levels of LD. We also include BEAGLE and IMPUTE2 for comparison. Experiment results with large reference panel suggest that our novel piecewise IBS method yields consistently higher imputation quality than other methods/software. The advantage is particularly noteworthy among uncommon variants where we observe up to 5.1% information gain with the difference being highly significant (Wilcoxon signed rank test P-value < 0.0001). Our work is the first that considers various sensible approaches for imputation in admixed populations and presents a comprehensive comparison. PMID:23074066

Pre-Whaling Genetic Diversity and Population Ecology in Eastern Pacific Gray Whales: Insights from Ancient DNA and Stable Isotopes

PubMed Central

Alter, S. Elizabeth; Newsome, Seth D.; Palumbi, Stephen R.

2012-01-01

Commercial whaling decimated many whale populations, including the eastern Pacific gray whale, but little is known about how population dynamics or ecology differed prior to these removals. Of particular interest is the possibility of a large population decline prior to whaling, as such a decline could explain the ∼5-fold difference between genetic estimates of prior abundance and estimates based on historical records. We analyzed genetic (mitochondrial control region) and isotopic information from modern and prehistoric gray whales using serial coalescent simulations and Bayesian skyline analyses to test for a pre-whaling decline and to examine prehistoric genetic diversity, population dynamics and ecology. Simulations demonstrate that significant genetic differences observed between ancient and modern samples could be caused by a large, recent population bottleneck, roughly concurrent with commercial whaling. Stable isotopes show minimal differences between modern and ancient gray whale foraging ecology. Using rejection-based Approximate Bayesian Computation, we estimate the size of the population bottleneck at its minimum abundance and the pre-bottleneck abundance. Our results agree with previous genetic studies suggesting the historical size of the eastern gray whale population was roughly three to five times its current size. PMID:22590499

A Population-based survey of the prevalence of HIV, syphilis, hepatitis B and hepatitis C infections and associated risk factors among young women in Vitória, Brazil

PubMed Central

Miranda, Angelica Espinosa; Figueiredo, Nínive Camilo; Schmidt, Renylena; Page-Shafer, Kimberly

2017-01-01

Objective To estimate the prevalence of HIV, hepatitis B (HBV) and C (HCV) and syphilis infections and associated risk exposures in a population-based sample of young women in Vitória, Brazil. Methods From March to December 2006, a cross-sectional sample of women aged 18 to 29 years was recruited into a single stage, population-based study. Serological markers of HIV, HBV, HCV, and syphilis infections and associated risk exposures were assessed. Results Of 1,200 eligible women, 1,029 (85.8%) enrolled. Median age was 23 (interquartile range [IQR] 20, 26) years; 32.2% had ≤ 8 years of education. The survey weighted prevalence estimates were: HIV, 0.6% (95% CI), 0.1%, 1.1%); anti-HBc, 4.2% (3.0%, 5.4%); HBsAg, 0.9% (0.4%, 1.6%); anti-HCV, 0.6% (0.1%, 1.1%) and syphilis 1.2% (0.5%, 1.9%). Overall, 6.1% had at least one positive serological marker for any of the tested infection. A majority (87.9%) was sexually active, of whom 12.1% reported a previously diagnosed sexually transmitted infection (STI) and 1.4% a history of commercial sex work. Variables independently associated with any positive serological test included: older age (≥25 vs. <25 years), low monthly income (≤ 4× vs. >4× minimum wage), previously diagnosed STI, ≥ 1 sexual partner, and any illicit drug use. Conclusions These are the first population-based estimates of the prevalence of exposure to these infectious diseases and related risks in young women, a population for whom there is a scarcity of data in Brazil. PMID:18401700

The Prevalence of Amblyopia and Its Determinants in a Population-based Study.

PubMed

Faghihi, Mohammad; Hashemi, Hassan; Nabovati, Payam; Saatchi, Mohammad; Yekta, Abbasali; Rafati, Shokoofeh; Ostadimoghaddam, Hadi; Khabazkhoob, Mehdi

2017-12-01

To determine the prevalence of amblyopia and its determinants in a population-based study in Mashhad County, Iran. This cross-sectional, population-based study was conducted on the population of Mashhad County aged >1 year using randomized stratified cluster sampling. Examinations were performed after selection of the participants and their free transportation to the sampling site. The examinations included the measurement of uncorrected and corrected visual acuity, cycloplegic and non-cycloplegic refraction, cover testing, slit-lamp biomicroscopy, and ophthalmoscopy. In this study, amblyopia was defined as best corrected visual acuity (BCVA) of 20/30 or less or 2-line interocular optotype acuity differences with no pathology. After considering the exclusion criteria, the data of 2739 individuals, 65.6% of whom were women, were analyzed. The mean age of the participants was 29.5±17.5 years. The prevalence of amblyopia was 4.6% (95% CI: 3.77%-5.43%) in the total population. The lowest prevalence was 2.24% in the age group 5-15 years (95% CI: 0.99%-3.48%) and the highest prevalence was 7.14% in the age group 55-65 years (95% CI: 2.64%-11.56%). Anisometropic amblyopia was observed in 45.24% of the amblyopic participants. Isometropic, mixed (strabismic/anisometropic), and strabismic amblyopia were other common causes of amblyopia, with a prevalence of 24.6%, 16.67%, and 13.49% in amblyopic patients, respectively. The odds ratio (OR) of having amblyopia for each 1-year increase in age was 1.02 (95% CI: 1.01-1.03). Amblyopia was less common in people with better socioeconomic status. This study showed the prevalence of amblyopia in all age groups in a population-based study for the first time. The findings of this study regarding the relatively high prevalence of amblyopia in the older population and its lower prevalence in young people indicate attention to amblyopia in recent years.

Authentication of Closely Related Fish and Derived Fish Products Using Tandem Mass Spectrometry and Spectral Library Matching.

PubMed

Nessen, Merel A; van der Zwaan, Dennis J; Grevers, Sander; Dalebout, Hans; Staats, Martijn; Kok, Esther; Palmblad, Magnus

2016-05-11

Proteomics methodology has seen increased application in food authentication, including tandem mass spectrometry of targeted species-specific peptides in raw, processed, or mixed food products. We have previously described an alternative principle that uses untargeted data acquisition and spectral library matching, essentially spectral counting, to compare and identify samples without the need for genomic sequence information in food species populations. Here, we present an interlaboratory comparison demonstrating how a method based on this principle performs in a realistic context. We also increasingly challenge the method by using data from different types of mass spectrometers, by trying to distinguish closely related and commercially important flatfish, and by analyzing heavily contaminated samples. The method was found to be robust in different laboratories, and 94-97% of the analyzed samples were correctly identified, including all processed and contaminated samples.

Changes in attitudes, intended behaviour, and mental health literacy in the Swedish population 2009-2014: an evaluation of a national antistigma programme.

PubMed

Hansson, L; Stjernswärd, S; Svensson, B

2016-08-01

Public stigma of mental illness is still a major problem where numerous population studies during the last decade have mainly shown no improvements. A Swedish national antistigma campaign has been running 2010-2014. The aim of this study was to investigate changes in public stigma during this period as compared to baseline in 2009. Yearly population surveys were made between 2009 and 2014 including assessments of mental health literacy, attitudes, and intended future behaviour. Two surveys were made, one including a nationally representative sample and one including a representative sample from three original campaign regions. Multiple regression analyses, also including age, gender, education, and familiarity with mental illness were made to investigate yearly changes in public stigma compared to baseline. Mental health literacy improved significantly in the campaign regions between 2009 and 2014, as did intended future behaviour. Attitudes toward mental illness also improved significantly. Improvements were also shown in the national population surveys, but the time pattern of these compared to that of the original campaign regions indicated that these changes took place mainly after the campaign had been extended to a further five Swedish regions. The results of our surveys suggest that a campaign primarily based on social contact theory and involving people with lived experience of mental illness may, even in a rather short-term perspective, have a significant positive impact on mental health literacy, attitudes, and intentions of social contact with people with mental illness. © 2016 The Authors. Acta Psychiatrica Scandinavica Published by John Wiley & Sons Ltd.

Development of a novel cell sorting method that samples population diversity in flow cytometry.

PubMed

Osborne, Geoffrey W; Andersen, Stacey B; Battye, Francis L

2015-11-01

Flow cytometry based electrostatic cell sorting is an important tool in the separation of cell populations. Existing instruments can sort single cells into multi-well collection plates, and keep track of cell of origin and sorted well location. However currently single sorted cell results reflect the population distribution and fail to capture the population diversity. Software was designed that implements a novel sorting approach, "Slice and Dice Sorting," that links a graphical representation of a multi-well plate to logic that ensures that single cells are sampled and sorted from all areas defined by the sort region/s. Therefore the diversity of the total population is captured, and the more frequently occurring or rarer cell types are all sampled. The sorting approach was tested computationally, and using functional cell based assays. Computationally we demonstrate that conventional single cell sorting can sample as little as 50% of the population diversity dependant on the population distribution, and that Slice and Dice sorting samples much more of the variety present within a cell population. We then show by sorting single cells into wells using the Slice and Dice sorting method that there are cells sorted using this method that would be either rarely sorted, or not sorted at all using conventional single cell sorting approaches. The present study demonstrates a novel single cell sorting method that samples much more of the population diversity than current methods. It has implications in clonal selection, stem cell sorting, single cell sequencing and any areas where population heterogeneity is of importance. © 2015 International Society for Advancement of Cytometry.

Out of sight, out of mind? The inclusion and identification of people with intellectual disability in public health research.

PubMed

Brooker, Katie; van Dooren, Kate; Tseng, Chih-Han; McPherson, Lyn; Lennox, Nick; Ware, Robert

2015-07-01

Adults with intellectual disability experience substantial health inequities. Public health research aiming to improve the lives of this population group is needed. We sought to investigate the extent to which a sample of international public health research includes and identifies people with intellectual disability. In this systematic review, we examined a select number of public health journals to determine (1) how often people with intellectual disability are explicitly included in randomised controlled trials (RCTs) and cohort studies and (2) how the presence of intellectual disability is identified and reported. Among eligible articles in these selected public health journals, it was found that cohort studies passively exclude people with intellectual disability, while RCTs actively exclude this population. Most general population articles that explicitly identified people with intellectual disability did so through self-report or proxy report and databases. A more extensive and adequate evidence base relating to the health of this overlooked population group is needed. A useful first step would be for researchers specialising in intellectual disability to identify how we can best assist mainstream researchers to include and identify people with intellectual disability in their population-level studies. © Royal Society for Public Health 2014.

Psychological Abuse between Parents: Associations with Child Maltreatment from a Population-Based Sample

ERIC Educational Resources Information Center

Chang, Jen Jen; Theodore, Adrea D.; Martin, Sandra L.; Runyan, Desmond K.

2008-01-01

Objective: This study examined the association between partner psychological abuse and child maltreatment perpetration. Methods: This cross-sectional study examined a population-based sample of mothers with children aged 0-17 years in North and South Carolina (n = 1,149). Mothers were asked about the occurrence of potentially neglectful or abusive…

Heritability of Autism Spectrum Disorder in a UK Population-Based Twin Sample

PubMed Central

Colvert, Emma; Tick, Beata; McEwen, Fiona; Stewart, Catherine; Curran, Sarah R.; Woodhouse, Emma; Gillan, Nicola; Hallett, Victoria; Lietz, Stephanie; Garnett, Tracy; Ronald, Angelica; Plomin, Robert; Rijsdijk, Frühling; Happé, Francesca; Bolton, Patrick

2016-01-01

IMPORTANCE Most evidence to date highlights the importance of genetic influences on the liability to autism and related traits. However, most of these findings are derived from clinically ascertained samples, possibly missing individuals with subtler manifestations, and obtained estimates may not be representative of the population. OBJECTIVES To establish the relative contributions of genetic and environmental factors in liability to autism spectrum disorder (ASD) and a broader autism phenotype in a large population-based twin sample and to ascertain the genetic/environmental relationship between dimensional trait measures and categorical diagnostic constructs of ASD. DESIGN, SETTING, AND PARTICIPANTS We used data from the population-based cohort Twins Early Development Study, which included all twin pairs born in England and Wales from January 1, 1994, through December 31, 1996. We performed joint continuous-ordinal liability threshold model fitting using the full information maximum likelihood method to estimate genetic and environmental parameters of covariance. Twin pairs underwent the following assessments: the Childhood Autism Spectrum Test (CAST) (6423 pairs; mean age, 7.9 years), the Development and Well-being Assessment (DAWBA) (359 pairs; mean age, 10.3 years), the Autism Diagnostic Observation Schedule (ADOS) (203 pairs; mean age, 13.2 years), the Autism Diagnostic Interview–Revised (ADI-R) (205 pairs; mean age, 13.2 years), and a best-estimate diagnosis (207 pairs). MAIN OUTCOMES AND MEASURES Participants underwent screening using a population-based measure of autistic traits (CAST assessment), structured diagnostic assessments (DAWBA, ADI-R, and ADOS), and a best-estimate diagnosis. RESULTS On all ASD measures, correlations among monozygotic twins (range, 0.77-0.99) were significantly higher than those for dizygotic twins (range, 0.22-0.65), giving heritability estimates of 56% to 95%. The covariance of CAST and ASD diagnostic status (DAWBA, ADOS and best-estimate diagnosis) was largely explained by additive genetic factors (76%-95%). For the ADI-R only, shared environmental influences were significant (30% [95% CI, 8%-47%]) but smaller than genetic influences (56% [95% CI, 37%-82%]). CONCLUSIONS AND RELEVANCE The liability to ASD and a more broadly defined high-level autism trait phenotype in this large population-based twin sample derives primarily from additive genetic and, to a lesser extent, nonshared environmental effects. The largely consistent results across different diagnostic tools suggest that the results are generalizable across multiple measures and assessment methods. Genetic factors underpinning individual differences in autismlike traits show considerable overlap with genetic influences on diagnosed ASD. PMID:25738232

Assessment of fracture risk: value of random population-based samples--the Geelong Osteoporosis Study.

PubMed

Henry, M J; Pasco, J A; Seeman, E; Nicholson, G C; Sanders, K M; Kotowicz, M A

2001-01-01

Fracture risk is determined by bone mineral density (BMD). The T-score, a measure of fracture risk, is the position of an individual's BMD in relation to a reference range. The aim of this study was to determine the magnitude of change in the T-score when different sampling techniques were used to produce the reference range. Reference ranges were derived from three samples, drawn from the same region: (1) an age-stratified population-based random sample, (2) unselected volunteers, and (3) a selected healthy subset of the population-based sample with no diseases or drugs known to affect bone. T-scores were calculated using the three reference ranges for a cohort of women who had sustained a fracture and as a group had a low mean BMD (ages 35-72 yr; n = 484). For most comparisons, the T-scores for the fracture cohort were more negative using the population reference range. The difference in T-scores reached 1.0 SD. The proportion of the fracture cohort classified as having osteoporosis at the spine was 26, 14, and 23% when the population, volunteer, and healthy reference ranges were applied, respectively. The use of inappropriate reference ranges results in substantial changes to T-scores and may lead to inappropriate management.

Sexual minority youth and depressive symptoms or depressive disorder: A systematic review and meta-analysis of population-based studies.

PubMed

Lucassen, Mathijs Fg; Stasiak, Karolina; Samra, Rajvinder; Frampton, Christopher Ma; Merry, Sally N

2017-08-01

Research has suggested that sexual minority young people are more likely to have depressive symptoms or depressive disorder, but to date most studies in the field have relied on convenience-based samples. This study overcomes this limitation by systematically reviewing the literature from population-based studies and conducting a meta-analysis to identify whether depressive disorder and depressive symptoms are elevated in sexual minority youth. A systematic review and meta-analysis were conducted and informed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement to determine if rates of depressive symptoms or depressive disorder differ for sexual minority youth, relative to heterosexual adolescents. MEDLINE, PsycINFO, EMBASE and ERIC databases were searched. Studies reporting depressive symptom data or the prevalence of depressive disorder in population-based samples of adolescents, which included sexual minority youth and heterosexual young people, were included in the review. A meta-analysis was conducted to examine differences between groups. Twenty-three articles met the inclusion criteria. The proportion of sexual minority youth in the studies ranged from 2.3% to 12%. Sexual minority youth reported higher rates of depressive symptoms and depressive disorder (odds ratio = 2.94, p < 0.001 and standardized mean difference, d = 0.39, p < 0.001) in comparison to heterosexual young people. Female sexual minority youth were more likely to report depressive symptoms when compared to male sexual minority youth (standardized mean difference, d = 0.34, p < 0.001). Limitations included variations in how sexuality was operationalized and how depressive symptoms or depressive disorder was measured. There is robust evidence that rates of depressive disorder and depressive symptoms are elevated in sexual minority youth in comparison to heterosexual young people. Despite the elevated risk of depressive symptoms or depressive disorder for sexual minority youth, the treatment for this group of young people has received little attention.

An illicit economy: scavenging and recycling of medical waste.

PubMed

Patwary, Masum A; O'Hare, William Thomas; Sarker, M H

2011-11-01

This paper discusses a significant illicit economy, including black and grey aspects, associated with medical waste scavenging and recycling in a megacity, considering hazards to the specific group involved in scavenging as well as hazards to the general population of city dwellers. Data were collected in Dhaka, Bangladesh, using a variety of techniques based on formal representative sampling for fixed populations (such as recycling operatives) and adaptive sampling for roaming populations (such as scavengers). Extremely hazardous items (including date expired medicines, used syringes, knives, blades and saline bags) were scavenged, repackaged and resold to the community. Some HCE employees were also observed to sell hazardous items directly to scavengers, and both employees and scavengers were observed to supply contaminated items to an informal plastics recycling industry. This trade was made possible by the absence of segregation, secure storage and proper disposal of medical waste. Corruption, a lack of accountability and individual responsibility were also found to be contributors. In most cases the individuals involved with these activities did not understand the risks. Although motivation was often for personal gain or in support of substance abuse, participants sometimes felt that they were providing a useful service to the community. Copyright © 2011 Elsevier Ltd. All rights reserved.

Single-Phase Mail Survey Design for Rare Population Subgroups

ERIC Educational Resources Information Center

Brick, J. Michael; Andrews, William R.; Mathiowetz, Nancy A.

2016-01-01

Although using random digit dialing (RDD) telephone samples was the preferred method for conducting surveys of households for many years, declining response and coverage rates have led researchers to explore alternative approaches. The use of address-based sampling (ABS) has been examined for sampling the general population and subgroups, most…

The rationale/design of the Guimarães/Vizela study: a multimodal population-based cohort study to determine global cardiovascular risk and disease.

PubMed

Cunha, Pedro Guimarães; Cotter, Jorge; Oliveira, Pedro; Vila, Isabel; Sousa, Nuno

2014-06-01

Cardiovascular disease and dementia are growing medical and social problems in aging societies. Appropriate knowledge of cardiovascular disease and cognitive decline risk factors (RFs) are critical for global CVR health preventive intervention. Many epidemiological studies use case definition based on data collected/measured in a single visit, a fact that can overestimate prevalence rates and distant from clinical practice demanding criteria. Portugal displays an elevated stroke mortality rate. However, population's global CV risk characterization is limited, namely, considering traditional/nontraditional RF and new intermediate phenotypes of CV and renal disease. Association of hemodynamic variables (pulse wave velocity and central blood pressure) with global CVR stratification, cognitive performance, and kidney disease are practically inexistent at a dwelling population level. After reviewing published data, we designed a population-based cohort study to analyze the prevalence of these cardiovascular RFs and intermediate phenotypes, using random sampling of adult dwellers living in 2 adjacent cities. Strict definition of phenotypes was planned: subjects were observed twice, and several hemodynamic and other biological variables measured at least 3 months apart. Three thousand thirty-eight subjects were enrolled, and extensive data collection (including central and peripheral blood pressure, pulse wave velocity), sample processing, and biobank edification were carried out. One thousand forty-seven cognitive evaluations were performed. Seeking for CV risk reclassification, early identification of subjects at risk, and evidence of early vascular aging and cognitive and renal function decline, using the strict daily clinical practice criteria, will lead to better resource allocation in preventive measures at a population level.

DSM-IV and DSM-5 Prevalence of Social Anxiety Disorder in a Population Sample of Older People.

PubMed

Karlsson, Björn; Sigström, Robert; Östling, Svante; Waern, Margda; Börjesson-Hanson, Anne; Skoog, Ingmar

2016-12-01

To examine the prevalence of social anxiety disorders (SAD) with (DSM-IV) and without (DSM-5) the person's own assessment that the fear was unreasonable, in a population sample of older adults. Further, to determine whether clinical and sociodemographic correlates of SAD differ depending on the criteria applied. Cross-sectional. General population in Gothenburg, Sweden. A random population-based sample of 75- and 85-year olds (N = 1200) without dementia. Psychiatric research nurses carried out a semi-structured psychiatric examination including the Comprehensive Psychopathological Rating Scale. DSM-IV SAD was diagnosed with the Mini International Neuropsychiatric Interview. SAD was diagnosed according to DSM-IV and DSM-5 criteria. The 6-month duration criterion in DSM-5 was not applied because of lack of information. Other assessments included the Global Assessment of Functioning (GAF), the Brief Scale for Anxiety (BSA), and the Montgomery Åsberg Depression Rating Scale (MADRS). The 1-month prevalence of SAD was 2.5% (N = 30) when the unreasonable fear criterion was defined in accordance with DSM-IV and 5.1% (N = 61) when the DSM-5 criterion was applied. Clinical correlates (GAF, MADRS, and BSA) were worse in SAD cases identified by either procedure compared with all others, and ratings for those reporting unreasonable fear suggested greater (albeit nonsignificant) overall psychopathology. Shifting the judgment of how reasonable the fear was, from the individual to the clinician, doubled the prevalence of SAD. This indicates that the DSM-5 version might increase prevalence rates of SAD in the general population. Further studies strictly applying all DSM-5 criteria are needed in order to confirm these findings. Copyright © 2016 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Mental Health Service Need and Use in the Aftermath of Hurricane Sandy: Findings in a Population-Based Sample of New York City Residents.

PubMed

Lowe, Sarah R; Sampson, Laura; Gruebner, Oliver; Galea, Sandro

2016-01-01

The majority of disaster survivors suffering from psychiatric disorders do not utilize mental health services. Only one study to date has explored postdisaster service use after Hurricane Sandy, and the disaster literature is further limited by a lack of attention to survivors' perceived need for services. We drew on data from a population-based sample of adults living in New York City neighborhoods that were most severely affected by Hurricane Sandy (N = 454). Less than 10 % of participants reported service needs (7.8 %) and service use (4.4 %) since the hurricane, 5.9 % were classified as having unmet needs (i.e., needs without use), and 2.5 % as using services without needs. Predictors of unmet mental health service needs included younger age, male gender, higher education, and exposure to more disaster-related stressors. The results suggest that efforts to reduce unmet postdisaster service needs could focus on reaching survivors with these characteristics.

Molecular analysis and genetic diversity of Aedes albopictus (Diptera, Culicidae) from China.

PubMed

Ruiling, Zhang; Peien, Leng; Xuejun, Wang; Zhong, Zhang

2018-05-01

Aedes albopictus is one of the most invasive species, which can carry Dengue virus, Yellow fever virus and more than twenty arboviruses. Based on mitochondrial gene cytochrome c oxidase I (COI) and samples collected from 17 populations, we investigated the molecular character and genetic diversity of Ae. albopictus from China. Altogether, 25 haplotypes were detected, including 10 shared haplotypes and 15 private haplotypes. H1 was the dominant haplotype, which is widely distributed in 13 populations. Tajima'D value of most populations was significantly negative, demonstrating that populations experienced rapid range expansion recently. Most haplotypes clustered together both in phylogenetic and median-joining network analysis without clear phylogeographic patterns. However, neutrality tests revealed shallow divergences among Hainan and Guangxi with other populations (0.15599 ≤ F ST ≤ 0.75858), which probably due to interrupted gene flow, caused by geographical isolations. In conclusion, Ae. albopictus populations showed low genetic diversity in China.

A comparison of home care clients and nursing home residents: can community based care keep the elderly and disabled at home?

PubMed

Shugarman, L R; Fries, B E; James, M

1999-01-01

Admission cohorts from the Michigan Medicaid Home and Community-Based Waiver program and Ohio nursing homes were compared on measures of resource utilization including a modified Resource Utilization Groups (RUG-III) system, Activities of Daily Living (ADLs), and overall case mix. We found that, contrary to previous research, the two samples were remarkably similar across RUG-III categories. However, the nursing home sample was more functionally impaired on measures of ADL functioning and overall case mix. Results of this study may inform policymakers and providers of the potential for maintaining the appropriate population in the home with government-funded home care.

Neurocognitive performance in family-based and case-control studies of schizophrenia

PubMed Central

Gur, Ruben C.; Braff, David L.; Calkins, Monica E.; Dobie, Dorcas J.; Freedman, Robert; Green, Michael F.; Greenwood, Tiffany A.; Lazzeroni, Laura C.; Light, Gregory A.; Nuechterlein, Keith H.; Olincy, Ann; Radant, Allen D.; Seidman, Larry J.; Siever, Larry J.; Silverman, Jeremy M.; Sprock, Joyce; Stone, William S.; Sugar, Catherine A.; Swerdlow, Neal R.; Tsuang, Debby W.; Tsuang, Ming T.; Turetsky, Bruce I.; Gur, Raquel E.

2014-01-01

Background Neurocognitive deficits in schizophrenia (SZ) are established and the Consortium on the Genetics of Schizophrenia (COGS) investigated such measures as endophenotypes in family-based (COGS-1) and case-control (COGS-2) studies. By requiring family participation, family-based sampling may result in samples that vary demographically and perform better on neurocognitive measures. Methods The Penn computerized neurocognitive battery (CNB) evaluates accuracy and speed of performance for several domains and was administered across sites in COGS-1 and COGS-2. Most tests were included in both studies. COGS-1 included 328 patients with SZ and 497 healthy comparison subjects (HCS) and COGS-2 included 1195 patients and 1009 HCS. Results Demographically, COGS-1 participants were younger, more educated, with more educated parents and higher estimated IQ compared to COGS-2 participants. After controlling for demographics, the two samples produced very similar performance profiles compared to their respective controls. As expected, performance was better and with smaller effect sizes compared to controls in COGS-1 relative to COGS-2. Better performance was most pronounced for spatial processing while emotion identification had large effect sizes for both accuracy and speed in both samples. Performance was positively correlated with functioning and negatively with negative and positive symptoms in both samples, but correlations were attenuated in COGS-2, especially with positive symptoms. Conclusions Patients ascertained through family-based design have more favorable demographics and better performance on some neurocognitive domains. Thus, studies that use case-control ascertainment may tap into populations with more severe forms of illness that are exposed to less favorable factors compared to those ascertained with family-based designs. PMID:25432636

Gradient-free MCMC methods for dynamic causal modelling

DOE PAGES

Sengupta, Biswa; Friston, Karl J.; Penny, Will D.

2015-03-14

Here, we compare the performance of four gradient-free MCMC samplers (random walk Metropolis sampling, slice-sampling, adaptive MCMC sampling and population-based MCMC sampling with tempering) in terms of the number of independent samples they can produce per unit computational time. For the Bayesian inversion of a single-node neural mass model, both adaptive and population-based samplers are more efficient compared with random walk Metropolis sampler or slice-sampling; yet adaptive MCMC sampling is more promising in terms of compute time. Slice-sampling yields the highest number of independent samples from the target density -- albeit at almost 1000% increase in computational time, in comparisonmore » to the most efficient algorithm (i.e., the adaptive MCMC sampler).« less

Genotyping faecal samples of Bengal tiger Panthera tigris tigris for population estimation: a pilot study.

PubMed

Bhagavatula, Jyotsna; Singh, Lalji

2006-10-17

Bengal tiger Panthera tigris tigris the National Animal of India, is an endangered species. Estimating populations for such species is the main objective for designing conservation measures and for evaluating those that are already in place. Due to the tiger's cryptic and secretive behaviour, it is not possible to enumerate and monitor its populations through direct observations; instead indirect methods have always been used for studying tigers in the wild. DNA methods based on non-invasive sampling have not been attempted so far for tiger population studies in India. We describe here a pilot study using DNA extracted from faecal samples of tigers for the purpose of population estimation. In this study, PCR primers were developed based on tiger-specific variations in the mitochondrial cytochrome b for reliably identifying tiger faecal samples from those of sympatric carnivores. Microsatellite markers were developed for the identification of individual tigers with a sibling Probability of Identity of 0.005 that can distinguish even closely related individuals with 99.9% certainty. The effectiveness of using field-collected tiger faecal samples for DNA analysis was evaluated by sampling, identification and subsequently genotyping samples from two protected areas in southern India. Our results demonstrate the feasibility of using tiger faecal matter as a potential source of DNA for population estimation of tigers in protected areas in India in addition to the methods currently in use.

Iron Age and Anglo-Saxon genomes from East England reveal British migration history

PubMed Central

Schiffels, Stephan; Haak, Wolfgang; Paajanen, Pirita; Llamas, Bastien; Popescu, Elizabeth; Loe, Louise; Clarke, Rachel; Lyons, Alice; Mortimer, Richard; Sayer, Duncan; Tyler-Smith, Chris; Cooper, Alan; Durbin, Richard

2016-01-01

British population history has been shaped by a series of immigrations, including the early Anglo-Saxon migrations after 400 CE. It remains an open question how these events affected the genetic composition of the current British population. Here, we present whole-genome sequences from 10 individuals excavated close to Cambridge in the East of England, ranging from the late Iron Age to the middle Anglo-Saxon period. By analysing shared rare variants with hundreds of modern samples from Britain and Europe, we estimate that on average the contemporary East English population derives 38% of its ancestry from Anglo-Saxon migrations. We gain further insight with a new method, rarecoal, which infers population history and identifies fine-scale genetic ancestry from rare variants. Using rarecoal we find that the Anglo-Saxon samples are closely related to modern Dutch and Danish populations, while the Iron Age samples share ancestors with multiple Northern European populations including Britain. PMID:26783965

Indian Craniometric Variability and Affinities

PubMed Central

Raghavan, Pathmanathan; Bulbeck, David; Pathmanathan, Gayathiri; Rathee, Suresh Kanta

2013-01-01

Recently published craniometric and genetic studies indicate a predominantly indigenous ancestry of Indian populations. We address this issue with a fuller coverage of Indian craniometrics than any done before. We analyse metrical variability within Indian series, Indians' sexual dimorphism, differences between northern and southern Indians, index-based differences of Indian males from other series, and Indians' multivariate affinities. The relationship between a variable's magnitude and its variability is log-linear. This relationship is strengthened by excluding cranial fractions and series with a sample size less than 30. Male crania are typically larger than female crania, but there are also shape differences. Northern Indians differ from southern Indians in various features including narrower orbits and less pronounced medial protrusion of the orbits. Indians resemble Veddas in having small crania and similar cranial shape. Indians' wider geographic affinities lie with “Caucasoid” populations to the northwest, particularly affecting northern Indians. The latter finding is confirmed from shape-based Mahalanobis-D distances calculated for the best sampled male and female series. Demonstration of a distinctive South Asian craniometric profile and the intermediate status of northern Indians between southern Indians and populations northwest of India confirm the predominantly indigenous ancestry of northern and especially southern Indians. PMID:24455409

Game On: Past Year Gambling, Gambling-Related Problems, and Fantasy Sports Gambling Among College Athletes and Non-athletes.

PubMed

Martin, Ryan J; Nelson, Sarah E; Gallucci, Andrew R

2016-06-01

College students experience higher rates of gambling-related problems than most other population segments, including the general population. Although Division I (D1) athletes often have more at stake than the average student if and when they gamble (e.g., the potential to lose their athletic eligibility), relatively few studies have assessed the gambling behavior of this population and none have specifically assessed fantasy sports gambling. We conducted a study to examine gambling behavior (past-year gambling, gambling-related problems, and fantasy sport gambling) among a sample (N = 692) of college students at a private religiously affiliated university in the Southwest US. The sample for our study was unique in that approximately 30 % of the participants were D1 athletes. We compared the gambling behavior among three groups based on the athlete status: D1 athletes, club/intramural/recreational (CIR) athletes, and non-athletes (NAs). Compared to females in our sample, males observed higher rates of past year gambling, fantasy sports participation, fantasy sports gambling, and gambling-related problems. Among males, we found that CIR athletes observed the highest rates of past year gambling and fantasy sports participation and D1 athletes observed higher rates than NAs. We did not find differences in fantasy sport gambling and past year gambling-related problems based on athlete status in males or females.

Movement and capture efficiency of radio-tagged salmonids sampled by electrofishing

Treesearch

Michael K. Young; David A. Schmetterling

2012-01-01

Electrofishing-based estimates of fish abundance are common. Most population models assume that samples are drawn froma closed population, but population closure is sometimes difficult to achieve. Consequently, we individually electrofished 103 radio-tagged trout of two species, westslope cutthroat trout Oncorhynchus clarkii lewisi and brook trout Salvelinus fontinalis...

Analysis of genetic data on Jewish populations. I. Historical background, demographic features, and genetic markers.

PubMed Central

Bonné-Tamir, B; Karlin, S; Kenett, R

1979-01-01

Part I describes the data sets on which the analysis of Part II is based. This covers the nature of the populations sampled, the extent to which the samples are representative, and a brief review of historical and demographic facts on the populations involved. PMID:380329

Population-based prevalence of smoking in psychiatric inpatients: a focus on acute suicide risk and major diagnostic groups.

PubMed

Lineberry, Timothy W; Allen, Josiah D; Nash, Jessica; Galardy, Christine W

2009-01-01

The aim of the study was to define the extent of current and lifetime smoking by diagnostic groups and suicide risk as reason for admission in a geographically defined psychiatric inpatient cohort. The study used a population-based retrospective chart review. Smoking status and discharge diagnoses for Olmsted County, Minnesota, inpatients aged 18 to 65 admitted for psychiatric hospitalization in 2004 and 2005 were abstracted from the electronic medical record. Diagnostic groups were compared to each other using chi(2) tests and Fisher exact test to analyze smoking status within the inpatient sample with significance defined as P

Prevalence and risk factors of intestinal protozoan infections: a population-based study in rural areas of Boyer-Ahmad district, Southwestern Iran.

PubMed

Sarkari, Bahador; Hosseini, Ghasem; Motazedian, Mohammad Hossein; Fararouei, Mohammad; Moshfe, Abdolali

2016-11-25

Parasitic infections are still a significant health problem in rural areas in developing countries including Iran. There is no recent population-based data about the prevalence of human intestinal parasites in most rural areas of Iran. The current study aimed to determine the prevalence of intestinal protozoan infection in inhabitants of rural areas of Boyer-Ahmad district, Southwestern Iran. A total of 1025 stool samples were collected from the inhabitant of 50 randomly selected villages in Boyer-Ahmad Township. The stool samples were evaluated by parasitological methods including, direct wet-mounting, formalin ethyl acetate concentration, zinc sulfate floatation, and Trichrome permanent stain for detection of protozoan infections. Diarrheic samples were further evaluated with a modified Ziehl-Neelsen staining method for detection of coccidian parasites. The prevalence of both pathogenic and nonpathogenic intestinal parasites in the population was 37.5% (385 out of 1025 cases), some individual with multiple infections. Giardia lamblia was detected in 179 (17.46%), Blastocystis hominis in 182 (17.76%), Entamoeba histolytica/dispar in 9 (0.87%), Endolimax nana in 216 (21.07%), Entamoeba coli in 151 (14.73%), Ioedamoeba butschlii in 45 (4.39%), Chillomastix mesnili in 22 (2.14%), Trichomonas hominis in 2 (0.19%) and Dientamoeba fragillis in 2 (0.19%) of cases. Multivariate logistic regression revealed significant associations between protozoan infection (pathogenic protozoa) and contact with animals (OR yes/no = 2.22, p < 0.001) and educational status (OR higher/illiterate = 0.40, P = 0.01). Findings of this study demonstrated that protozoan infection rate in rural areas of southwestern Iran is still high and remained as a challenging health problem in these areas.

Normative values of cognitive and physical function in older adults: findings from the Irish Longitudinal Study on Ageing.

PubMed

Kenny, Rose Anne; Coen, Robert F; Frewen, John; Donoghue, Orna A; Cronin, Hilary; Savva, George M

2013-05-01

To provide normative values of tests of cognitive and physical function based on a large sample representative of the population of Ireland aged 50 and older. Data were used from the first wave of The Irish Longitudinal Study on Ageing (TILDA), a prospective cohort study that includes a comprehensive health assessment. Health assessment was undertaken at one of two dedicated health assessment centers or in the study participant's home if travel was not practicable. Five thousand eight hundred ninety-seven members of a nationally representative sample of the community-living population of Ireland aged 50 and older. Those with severe cognitive impairment, dementia, or Parkinson's disease were excluded. Measurements included height and weight, normal walking speed, Timed Up-and-Go, handgrip strength, Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Color Trails Test, and bone mineral density. Normative values were estimated using generalized additive models for location shape and scale (GAMLSS) and are presented as percentiles, means, and standard deviations. Generalized additive models for location shape and scale fit the observed data well for each measure, leading to reliable estimates of normative values. Performance on all tasks decreased with age. Educational attainment was a strong determinant of performance on all cognitive tests. Tests of walking speed were dependent on height. Distribution of body mass index did not change with age, owing to simultaneous declines in weight and height. Normative values were found for tests of many aspects of cognitive and physical function based on a representative sample of the general older Irish population. © 2013, Copyright the Authors Journal compilation © 2013, The American Geriatrics Society.

Impact of in-Sewer Degradation of Pharmaceutical and Personal Care Products (PPCPs) Population Markers on a Population Model.

PubMed

O'Brien, Jake William; Banks, Andrew Phillip William; Novic, Andrew Joseph; Mueller, Jochen F; Jiang, Guangming; Ort, Christoph; Eaglesham, Geoff; Yuan, Zhiguo; Thai, Phong K

2017-04-04

A key uncertainty of wastewater-based epidemiology is the size of the population which contributed to a given wastewater sample. We previously developed and validated a Bayesian inference model to estimate population size based on 14 population markers which: (1) are easily measured and (2) have mass loads which correlate with population size. However, the potential uncertainty of the model prediction due to in-sewer degradation of these markers was not evaluated. In this study, we addressed this gap by testing their stability under sewer conditions and assessed whether degradation impacts the model estimates. Five markers, which formed the core of our model, were stable in the sewers while the others were not. Our evaluation showed that the presence of unstable population markers in the model did not decrease the precision of the population estimates providing that stable markers such as acesulfame remained in the model. However, to achieve the minimum uncertainty in population estimates, we propose that the core markers to be included in population models for other sites should meet two additional criteria: (3) negligible degradation in wastewater to ensure the stability of chemicals during collection; and (4) < 10% in-sewer degradation could occur during the mean residence time of the sewer network.

Relation of type 2 diabetes mellitus with gender, education, and marital status in an Iranian urban population.

PubMed

Rahmanian, Karamatollah; Shojaei, Mohammad; Sotoodeh Jahromi, Abdolreza

2013-04-01

Type 2 diabetes mellitus is one of the most important cardiovascular risk factors. This study was performed to assess the relationship of diabetes with gender, education, and marital status in an Iranian urban population. A total of 892 men and women aged 30-85 were recruited using a cluster-stratified sampling method from an urban population. Using a questionnaire, demographical data including gender, education, and marital status were collected. A blood sample after fasting for at least eight hours was collected from each subject. Associations of type 2 diabetes mellitus and studied variables were tested for significance. The prevalence of diabetes mellitus was 11.6%; 11.1% in men and 12.1% in women with no significant difference between them. Diabetes mellitus was most prevalent in the oldest age (age more than 60 years, 22.9%) and low education groups (17.9%, P < 0.001). Marital status was not significantly related to diabetes mellitus (P= 0.37). The prevalence of diabetes mellitus is related to education within the Iranian population. Thus preventive strategies should be based on the affective factors.

Simulated rRNA/DNA Ratios Show Potential To Misclassify Active Populations as Dormant

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

Steven, Blaire; Hesse, Cedar; Soghigian, John

The use of rRNA/DNA ratios derived from surveys of rRNA sequences in RNA and DNA extracts is an appealing but poorly validated approach to infer the activity status of environmental microbes. To improve the interpretation of rRNA/DNA ratios, we performed simulations to investigate the effects of community structure, rRNA amplification, and sampling depth on the accuracy of rRNA/DNA ratios in classifying bacterial populations as “active” or “dormant.” Community structure was an insignificant factor. In contrast, the extent of rRNA amplification that occurs as cells transition from dormant to growing had a significant effect (P < 0.0001) on classification accuracy, withmore » misclassification errors ranging from 16 to 28%, depending on the rRNA amplification model. The error rate increased to 47% when communities included a mixture of rRNA amplification models, but most of the inflated error was false negatives (i.e., active populations misclassified as dormant). Sampling depth also affected error rates (P < 0.001). Inadequate sampling depth produced various artifacts that are characteristic of rRNA/DNA ratios generated from real communities. These data show important constraints on the use of rRNA/DNA ratios to infer activity status. Whereas classification of populations as active based on rRNA/DNA ratios appears generally valid, classification of populations as dormant is potentially far less accurate.« less

[Genetic Differentiation of Sockeye Salmon Oncorhynchus nerka from Kamchatka River Basin and the Lake-River Systems of the West Coast of the Bering Sea as Inferred from Data on Single Nucleotide Polymorphism].

PubMed

Khrustaleva, A M; Klovach, N V; Vedischeva, E V; Seeb, J E

2015-10-01

The variability of 45 single nucleotide polymorphism loci (SNP) was studied in sockeye salmon from the Kamchatka River basin and four lake-river systems of the west coast of the Bering Sea. Based on the genetic differentiation estimates for the largest sockeye salmon populations of Eastern Kamchatka and Chukotka, the examined samples were combined into two regional groups represented by the population of the Kamchatka River drainage, which included numerous local subpopulations and seasonal races, and the northern population grouping from the rivers of Olutorsko-Navarinsky raion, wherein the sockeye salmon from Maynypilginskaya Lake-River system was relatively isolated. Considerable divergence was observed between the island (Sarannoe Lake, Bering Island) and continental populations. Genetic heterogeneity was revealed and groups of early- and late-maturing individuals were isolated in the sample of late-run sockeye salmon from Kamchatka River. In Apuka River, subdivision of the spawning run into two genetically distinct spatial and temporal groupings was also observed. The results suggest that the differentiation of sockeye salmon samples by single nucleotide substitution frequencies was largely due to differences in the direction and strength of local selection at some loci in the population complexes and intrapopulation groupings from the examined river basins of Eastern Kamchatka, Chukotka, and Commander Islands.

Simulated rRNA/DNA Ratios Show Potential To Misclassify Active Populations as Dormant

DOE PAGES

Steven, Blaire; Hesse, Cedar; Soghigian, John; ...

2017-03-31

The use of rRNA/DNA ratios derived from surveys of rRNA sequences in RNA and DNA extracts is an appealing but poorly validated approach to infer the activity status of environmental microbes. To improve the interpretation of rRNA/DNA ratios, we performed simulations to investigate the effects of community structure, rRNA amplification, and sampling depth on the accuracy of rRNA/DNA ratios in classifying bacterial populations as “active” or “dormant.” Community structure was an insignificant factor. In contrast, the extent of rRNA amplification that occurs as cells transition from dormant to growing had a significant effect (P < 0.0001) on classification accuracy, withmore » misclassification errors ranging from 16 to 28%, depending on the rRNA amplification model. The error rate increased to 47% when communities included a mixture of rRNA amplification models, but most of the inflated error was false negatives (i.e., active populations misclassified as dormant). Sampling depth also affected error rates (P < 0.001). Inadequate sampling depth produced various artifacts that are characteristic of rRNA/DNA ratios generated from real communities. These data show important constraints on the use of rRNA/DNA ratios to infer activity status. Whereas classification of populations as active based on rRNA/DNA ratios appears generally valid, classification of populations as dormant is potentially far less accurate.« less

Estimating mean change in population salt intake using spot urine samples.

PubMed

Petersen, Kristina S; Wu, Jason H Y; Webster, Jacqui; Grimes, Carley; Woodward, Mark; Nowson, Caryl A; Neal, Bruce

2017-10-01

Spot urine samples are easier to collect than 24-h urine samples and have been used with estimating equations to derive the mean daily salt intake of a population. Whether equations using data from spot urine samples can also be used to estimate change in mean daily population salt intake over time is unknown. We compared estimates of change in mean daily population salt intake based upon 24-h urine collections with estimates derived using equations based on spot urine samples. Paired and unpaired 24-h urine samples and spot urine samples were collected from individuals in two Australian populations, in 2011 and 2014. Estimates of change in daily mean population salt intake between 2011 and 2014 were obtained directly from the 24-h urine samples and by applying established estimating equations (Kawasaki, Tanaka, Mage, Toft, INTERSALT) to the data from spot urine samples. Differences between 2011 and 2014 were calculated using mixed models. A total of 1000 participants provided a 24-h urine sample and a spot urine sample in 2011, and 1012 did so in 2014 (paired samples n = 870; unpaired samples n = 1142). The participants were community-dwelling individuals living in the State of Victoria or the town of Lithgow in the State of New South Wales, Australia, with a mean age of 55 years in 2011. The mean (95% confidence interval) difference in population salt intake between 2011 and 2014 determined from the 24-h urine samples was -0.48g/day (-0.74 to -0.21; P < 0.001). The corresponding result estimated from the spot urine samples was -0.24 g/day (-0.42 to -0.06; P = 0.01) using the Tanaka equation, -0.42 g/day (-0.70 to -0.13; p = 0.004) using the Kawasaki equation, -0.51 g/day (-1.00 to -0.01; P = 0.046) using the Mage equation, -0.26 g/day (-0.42 to -0.10; P = 0.001) using the Toft equation, -0.20 g/day (-0.32 to -0.09; P = 0.001) using the INTERSALT equation and -0.27 g/day (-0.39 to -0.15; P < 0.001) using the INTERSALT equation with potassium. There was no evidence that the changes detected by the 24-h collections and estimating equations were different (all P > 0.058). Separate analysis of the unpaired and paired data showed that detection of change by the estimating equations was observed only in the paired data. All the estimating equations based upon spot urine samples identified a similar change in daily salt intake to that detected by the 24-h urine samples. Methods based upon spot urine samples may provide an approach to measuring change in mean population salt intake, although further investigation in larger and more diverse population groups is required. © The Author 2016; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

Family-based association study between monoamine oxidase A (MAOA) gene promoter VNTR polymorphism and Tourette's syndrome in Chinese Han population.

PubMed

Liu, Shiguo; Wang, Xueqin; Xu, Longqiang; Zheng, Lanlan; Ge, Yinlin; Ma, Xu

2015-02-01

To clarify the association of monoamine oxidase A- variable number of tandem repeat (MAOA-pVNTR) with susceptibility to Tourette's syndrome (TS) in Chinese Han population we discuss the genetic contribution of MAOA-VNTR in 141 TS patients including all their parents in Chinese Han population using transmission disequilibrium test (TDT) design. Our results revealed that no significant association was found in the MAOA gene promoter VNTR polymorphism and TS in Chinese Han population (TDT = 1.515, df = 1, p > 0.05). The negative result may be mainly due to the small sample size, but we don't deny the role of gene coding serotonergic or monoaminergic structures in the etiology of TS.

HormoneBase, a population-level database of steroid hormone levels across vertebrates

PubMed Central

Vitousek, Maren N.; Johnson, Michele A.; Donald, Jeremy W.; Francis, Clinton D.; Fuxjager, Matthew J.; Goymann, Wolfgang; Hau, Michaela; Husak, Jerry F.; Kircher, Bonnie K.; Knapp, Rosemary; Martin, Lynn B.; Miller, Eliot T.; Schoenle, Laura A.; Uehling, Jennifer J.; Williams, Tony D.

2018-01-01

Hormones are central regulators of organismal function and flexibility that mediate a diversity of phenotypic traits from early development through senescence. Yet despite these important roles, basic questions about how and why hormone systems vary within and across species remain unanswered. Here we describe HormoneBase, a database of circulating steroid hormone levels and their variation across vertebrates. This database aims to provide all available data on the mean, variation, and range of plasma glucocorticoids (both baseline and stress-induced) and androgens in free-living and un-manipulated adult vertebrates. HormoneBase (www.HormoneBase.org) currently includes >6,580 entries from 476 species, reported in 648 publications from 1967 to 2015, and unpublished datasets. Entries are associated with data on the species and population, sex, year and month of study, geographic coordinates, life history stage, method and latency of hormone sampling, and analysis technique. This novel resource could be used for analyses of the function and evolution of hormone systems, and the relationships between hormonal variation and a variety of processes including phenotypic variation, fitness, and species distributions. PMID:29786693

Long‐term trends in fall age ratios of black brant

USGS Publications Warehouse

Ward, David H.; Amundson, Courtney L.; Stehn, Robert A.; Dau, Christian P.

2018-01-01

Accurate estimates of the age composition of populations can inform past reproductive success and future population trajectories. We examined fall age ratios (juveniles:total birds) of black brant (Branta bernicla nigricans; brant) staging at Izembek National Wildlife Refuge near the tip of the Alaska Peninsula, southwest Alaska, USA, 1963 to 2015. We also investigated variation in fall age ratios associated with sampling location, an index of flock size, survey effort, day of season, observer, survey platform (boat‐ or land‐based) and tide stage. We analyzed data using logistic regression models implemented in a Bayesian framework. Mean predicted fall age ratio controlling for survey effort, day of year, and temporal and spatial variation was 0.24 (95% CL = 0.23, 0.25). Overall trend in age ratios was −0.6% per year (95% CL = −1.3%, 0.2%), resulting in an approximate 26% decline in the proportion of juveniles over the study period. We found evidence for variation across a range of variables implying that juveniles are not randomly distributed in space and time within Izembek Lagoon. Age ratios varied by location within the study area and were highly variable among years. They decreased with the number of birds aged (an index of flock size) and increased throughout September before leveling off in early October and declining in late October. Age ratios were similar among tide stages and observers and were lower during boat‐based (offshore) than land‐based (nearshore) surveys. Our results indicate surveys should be conducted annually during early to mid‐October to ensure the entire population is present and available for sampling, and throughout Izembek Lagoon to account for spatiotemporal variation in age ratios. Sampling should include a wide range of flock sizes representative of their distribution and occur in flocks located near and off shore. Further research evaluating the cause of declining age ratios in the fall population is necessary to inform management and predict long‐term population dynamics of brant.

Evaluating Nicotine Replacement Therapy and Stage-Based Therapies in a Population-Based Effectiveness Trial

ERIC Educational Resources Information Center

Velicer, Wayne F.; Friedman, Robert H.; Fava, Joseph L.; Gulliver, Suzy B.; Keller, Stefan; Sun, Xiaowu; Ramelson, Harley; Prochaska, James O.

2006-01-01

Pharmacological interventions for smoking cessation are typically evaluated using volunteer samples (efficacy trials) but should also be evaluated in population-based trials (effectiveness trials). Nicotine replacement therapy (NRT) alone and in combination with behavioral interventions was evaluated on a population of smokers from a New England…

A Venue-Based Approach to Reaching MSM, IDUs and the General Population with VCT: A Three Study Site in Kenya

PubMed Central

Singh, Kavita; Brodish, Paul; Mbai, Fiona; Kingola, Nzioki; Rinyuri, Agnes; Njeru, Carol; Mureithi, Patrick; Sambisa, William; Weir, Sharon

2014-01-01

A venue-based HIV prevention study which included Voluntary Counseling and Testing (VCT) was conducted in three diverse areas of Kenya— Malindi, Nanyuki and Rachounyo. Aims of the study were to: 1) assess the acceptability of VCT for the general population, men who have sex with men (MSM), and injecting drug users (IDUs) within the context of a venue-based approach; 2) determine if there were differences between those agreeing and not agreeing to testing; and 3) study factors associated with being HIV positive. Approximately 98% of IDUs and 97% of MSM agreed to VCT, providing evidence that populations with little access to services and whose behaviors are stigmatized and often considered illegal in their countries can be reached with needed HIV prevention services. Acceptability of VCT in the general population ranged from 60% in Malindi to 48% in Nanyuki. There were a few significant differences between those accepting and declining testing. Notably in Rachuonyo and Malindi those reporting multiple partners were more likely to accept testing. There was also evidence that riskier sexual behavior was associated with being HIV positive for both men in Rachounyo and women in Malindi. Overall HIV prevalence was higher among the individuals in this study compared to individuals sampled in the 2008–2009 Kenya Demographic and Health Survey, indicating the method is an appropriate means to reach the highest risk individuals including stigmatized populations. PMID:22198312

Genetic Diversity and Geographic Population Structure of Bovine Neospora caninum Determined by Microsatellite Genotyping Analysis

PubMed Central

Regidor-Cerrillo, Javier; Díez-Fuertes, Francisco; García-Culebras, Alicia; Moore, Dadín P.; González-Warleta, Marta; Cuevas, Carmen; Schares, Gereon; Katzer, Frank; Pedraza-Díaz, Susana; Mezo, Mercedes; Ortega-Mora, Luis M.

2013-01-01

The cyst-forming protozoan parasite Neospora caninum is one of the main causes of bovine abortion worldwide and is of great economic importance in the cattle industry. Recent studies have revealed extensive genetic variation among N . caninum isolates based on microsatellite sequences (MSs). MSs may be suitable molecular markers for inferring the diversity of parasite populations, molecular epidemiology and the basis for phenotypic variations in N . caninum , which have been poorly defined. In this study, we evaluated nine MS markers using a panel of 11 N . caninum -derived reference isolates from around the world and 96 N . caninum bovine clinical samples and one ovine clinical sample collected from four countries on two continents, including Spain, Argentina, Germany and Scotland, over a 10-year period. These markers were used as molecular tools to investigate the genetic diversity, geographic distribution and population structure of N . caninum . Multilocus microsatellite genotyping based on 7 loci demonstrated high levels of genetic diversity in the samples from all of the different countries, with 96 microsatellite multilocus genotypes (MLGs) identified from 108 N . caninum samples. Geographic sub-structuring was present in the country populations according to pairwise F ST. Principal component analysis (PCA) and Neighbor Joining tree topologies also suggested MLG segregation partially associated with geographical origin. An analysis of the MLG relationships, using eBURST, confirmed that the close genetic relationship observed between the Spanish and Argentinean populations may be the result of parasite migration (i.e., the introduction of novel MLGs from Spain to South America) due to cattle movement. The eBURST relationships also revealed genetically different clusters associated with the abortion. The presence of linkage disequilibrium, the co-existence of specific MLGs to individual farms and eBURST MLG relationships suggest a predominant clonal propagation for Spanish N . caninum MLGs in cattle. PMID:23940816

Science Achievement of Elementary and Secondary School Students in Japan: The Results of the IEA Study. NIER Occasional Paper 01/89.

ERIC Educational Resources Information Center

Miyake, Misao

This document reports the state of science achievement of Japanese students based on the Second International Science study conducted in 1983-84. Results are compared to the first study conducted in 1970. The target populations, samples, and structure of the second study are described. Test results including score distribution and high and low…

Sex Differences in Left-Handedness Are Also Evident in Scandinavia and in Twins: Comment on Papadatou-Pastou, Martin, Munafo, and Jones (2008)

ERIC Educational Resources Information Center

Vuoksimaa, Eero; Kaprio, Jaakko

2010-01-01

The lack of sex difference in left-handedness in Scandinavian countries reported by Papadatou-Pastou, Martin, Munafo, and Jones (2008) is questioned. We investigated the sex difference in left-handedness in two Finnish, one Norwegian, and one Swedish population-based sample not included in the Papadatou-Pastou et al. (2008) meta-analysis. The…

Prevalence and risk factors of excessive daytime sleepiness in a community sample of young children: the role of obesity, asthma, anxiety/depression, and sleep.

PubMed

Calhoun, Susan L; Vgontzas, Alexandros N; Fernandez-Mendoza, Julio; Mayes, Susan D; Tsaoussoglou, Marina; Basta, Maria; Bixler, Edward O

2011-04-01

We investigated the prevalence and association of excessive daytime sleepiness (EDS) with a wide range of factors (e.g., medical complaints, obesity, objective sleep [including sleep disordered breathing], and parent-reported anxiety/depression and sleep difficulties) in a large general population sample of children. Few studies have researched the prevalence and predictors of EDS in young children, none in a general population sample of children, and the results are inconsistent. Cross-sectional Population -based. 508 school-aged children from the general population. N/A. Children underwent a 9-hour polysomnogram (PSG), physical exam, and parent completed health, sleep and psychological questionnaires. Children were divided into 2 groups: those with and without parent reported EDS. The prevalence of subjective EDS was approximately 15%. Significant univariate relationships were found between children with EDS and BMI percentile, waist circumference, heartburn, asthma, and parent reported anxiety/depression, and sleep difficulties. The strongest predictors of EDS were waist circumference, asthma, and parent-reported symptoms of anxiety/depression and trouble falling asleep. All PSG sleep variables including apnea/hypopnea index, caffeine consumption, and allergies were not significantly related to EDS. It appears that the presence of EDS is more strongly associated with obesity, asthma, parent reported anxiety/depression, and trouble falling asleep than with sleep disordered breathing (SDB) or objective sleep disruption per se. Our findings suggest that children with EDS should be thoroughly assessed for anxiety/depression, nocturnal sleep difficulties, asthma, obesity, and other metabolic factors, whereas objective sleep findings may not be as clinically useful.

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.

COMPACT GALACTIC PLANETARY NEBULAE: AN HST /WFC3 MORPHOLOGICAL CATALOG, AND A STUDY OF THEIR ROLE IN THE GALAXY

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

Stanghellini, Letizia; Shaw, Richard A.; Villaver, Eva

We present the images of a Hubble Space Telescope ( HST /WFC3) snapshot program of angularly compact Galactic planetary nebulae (PNe), acquired with the aim of studying their size, evolutionary status, and morphology. PNe that are smaller than ∼4″ are underrepresented in most morphological studies, and today they are less well studied than their immediate evolutionary predecessors, the pre-planetary nebulae. The images have been acquired in the light of [O iii] λ 5007, which is commonly used to classify the PN morphology, in the UV continuum with the aim of detecting the central star unambiguously, and in the I -bandmore » to detect a cool stellar companion, if present. The sample of 51 confirmed PNe exhibits nearly the full range of primary morphological classes, with the distribution more heavily weighted toward bipolar PNe, but with the total of aspherical PNe almost identical to that of the general Galactic sample. A large range of microstructures is evident in our sample as well, with many nebulae displaying attached shells, halos, ansae, and internal structure in the form of arcs, rings, and spirals. Various aspherical structures in a few PNe, including detached arcs, suggest an interaction with the ISM. We studied the observed sample of compact Galactic PNe in the context of the general Galactic PN population, and explore whether their physical size, spatial distribution, reddening, radial metallicity gradient, and possible progenitors are peculiar within the population of Galactic PNe. We found that these compact Galactic PNe, which have been selected based on apparent dimensions, constitute a diverse Galactic PN population that is relatively uniformly distributed across the Galactic disk, including the outskirts of our Galaxy. This unique sample will be used in the future to probe the old Galactic disk population.« less

Australian health-related quality of life population norms derived from the SF-6D.

PubMed

Norman, Richard; Church, Jody; van den Berg, Bernard; Goodall, Stephen

2013-02-01

To investigate population health-related quality of life norms in an Australian general sample by age, gender, BMI, education and socioeconomic status. The SF-36 was included in the 2009/10 wave of the Household, Income and Labour Dynamics in Australia (HILDA) survey (n=17,630 individuals across 7,234 households), and converted into SF-6D utility scores. Trends across the various population subgroups were investigated employing population weights to ensure a balanced panel, and were all sub-stratified by gender. SF-6D scores decline with age beyond 40 years, with decreasing education and by higher levels of socioeconomic disadvantage. Scores were also lower at very low and very high BMI levels. Males reported higher SF-6D scores than females across most analyses. This study reports Australian population utility data measured using the SF-6D, based on a national representative sample. These results can be used in a range of policy settings such as cost-utility analysis or exploration of health-related inequality. In general, the patterns are similar to those reported using other multi-attribute utility instruments and in different countries. © 2013 The Authors. ANZJPH © 2013 Public Health Association of Australia.

Intimate Partner Violence and Depression in a Population-Based Sample of Women: Can Social Support Help?

ERIC Educational Resources Information Center

Mburia-Mwalili, Adel; Clements-Nolle, Kristen; Lee, William; Shadley, Meri; Wei Yang,

2010-01-01

Data from the 2006 Behavioral Risk Factor Surveillance System in Nevada was analyzed to determine whether social support is independently associated with depression in a population-based sample of women with a history of intimate partner violence (IPV). More than a quarter (27%) of the women who were randomly chosen to participate in the survey…

Men's and Women's Health Beliefs Differentially Predict Coronary Heart Disease Incidence in a Population-Based Sample

ERIC Educational Resources Information Center

Korin, Maya Rom; Chaplin, William F.; Shaffer, Jonathan A.; Butler, Mark J.; Ojie, Mary-Jane; Davidson, Karina W.

2013-01-01

Objective: To examine gender differences in the association between beliefs in heart disease preventability and 10-year incidence of coronary heart disease (CHD) in a population-based sample. Methods: A total of 2,688 Noninstitutionalized Nova Scotians without prior CHD enrolled in the Nova Scotia Health Study (NSHS95) and were followed for 10…

Predictors of health care seeking for irritable bowel syndrome: a population based study.

PubMed

Talley, N J; Boyce, P M; Jones, M

1997-09-01

It has been suggested that psychological factors rather than symptoms drive subjects with irritable bowel syndrome (IBS) to seek medical care, but this issue has not been tackled in a population based study. To identify whether psychological factors or abuse explain health care seeking for IBS. A sample of residents of Penrith (a Sydney suburb representative of the Australian population) selected randomly from the electoral rolls (that by law include the entire population > or = 18 years) was mailed a validated self-report questionnaire. Measured were gastrointestinal symptoms including the Manning (and Rome) criteria for IBS, health care seeking, neuroticism (Eysenck Personality Questionnaire), psychological morbidity (General Health Questionnaire: GHQ) and sexual, physical and emotional abuse (including the standardised Drossman questions). Among 730 subjects, 96 (13%, 95% confidence interval (CI) 11-16%) had IBS by the Manning criteria. Of those with IBS, 73% (95% CI 63-81%) had sought medical care for abdominal pain or discomfort. Only increasing pain severity (odds ratio (OR) = 2.10, 95% CI 1.11-3.95) and duration of pain (OR = 1.53, 95% CI 1.10-2.13) were independently associated with seeking health care for IBS. Pain severity was also predictive of recent care seeking (OR = 1.74, 95% CI 1.12-1.96). Neuroticism, psychological morbidity and abuse history were not significant predictors. Psychological factors do not seem to explain health care seeking among community subjects with IBS.

Paternal genetic affinity between western Austronesians and Daic populations

PubMed Central

2008-01-01

Background Austronesian is a linguistic family spread in most areas of the Southeast Asia, the Pacific Ocean, and the Indian Ocean. Based on their linguistic similarity, this linguistic family included Malayo-Polynesians and Taiwan aborigines. The linguistic similarity also led to the controversial hypothesis that Taiwan is the homeland of all the Malayo-Polynesians, a hypothesis that has been debated by ethnologists, linguists, archaeologists, and geneticists. It is well accepted that the Eastern Austronesians (Micronesians and Polynesians) derived from the Western Austronesians (Island Southeast Asians and Taiwanese), and that the Daic populations on the mainland are supposed to be the headstream of all the Austronesian populations. Results In this report, we studied 20 SNPs and 7 STRs in the non-recombining region of the 1,509 Y chromosomes from 30 China Daic populations, 23 Indonesian and Vietnam Malayo-Polynesian populations, and 11 Taiwan aboriginal populations. These three groups show many resemblances in paternal lineages. Admixture analyses demonstrated that the Daic populations are hardly influenced by Han Chinese genetically, and that they make up the largest proportion of Indonesians. Most of the population samples contain a high frequency of haplogroup O1a-M119, which is nearly absent in other ethnic families. The STR network of haplogroup O1a* illustrated that Indonesian lineages did not derive from Taiwan aborigines as linguistic studies suggest, but from Daic populations. Conclusion We show that, in contrast to the Taiwan homeland hypothesis, the Island Southeast Asians do not have a Taiwan origin based on their paternal lineages. Furthermore, we show that both Taiwan aborigines and Indonesians likely derived from the Daic populations based on their paternal lineages. These two populations seem to have evolved independently of each other. Our results indicate that a super-phylum, which includes Taiwan aborigines, Daic, and Malayo-Polynesians, is genetically educible. PMID:18482451

Post-traumatic stress disorder in older adults: a systematic review of the psychotherapy treatment literature.

PubMed

Dinnen, Stephanie; Simiola, Vanessa; Cook, Joan M

2015-01-01

Older adults represent the fastest growing segment of the US and industrialized populations. However, older adults have generally not been included in randomized clinical trials of psychotherapy for post-traumatic stress disorder (PTSD). This review examined reports of psychological treatment for trauma-related problems, primarily PTSD, in studies with samples of at least 50% adults aged 55 and older using standardized measures. A systematic review of the literature was conducted on psychotherapy for PTSD with older adults using PubMed, Medline, PsychInfo, CINAHL, PILOTS, and Google Scholar. A total of 42 studies were retrieved for full review; 22 were excluded because they did not provide at least one outcome measure or results were not reported by age in the case of mixed-age samples. Of the 20 studies that met review criteria, there were: 13 case studies or series, three uncontrolled pilot studies, two randomized clinical trials, one non-randomized concurrent control study and one post hoc effectiveness study. Significant methodological limitations in the current older adult PTSD treatment outcome literature were found reducing its internal validity and generalizability, including non-randomized research designs, lack of comparison conditions and small sample sizes. Select evidence-based interventions validated in younger and middle-aged populations appear acceptable and efficacious with older adults. There are few treatment studies on subsets of the older adult population including cultural and ethnic minorities, women, the oldest old (over 85), and those who are cognitively impaired. Implications for clinical practice and future research directions are discussed.

Marsh birds and the North American Breeding Bird Survey: judging the value of a landscape level survey for habitat specialist species with low detection rates

USGS Publications Warehouse

Sauer, J.R.

1999-01-01

The North American Breeding Bird Survey was started in 1966, and provides information on population change for >400 species of birds. it covers the continental United States, Canada, and Alaska, and is conducted once each year, in June, by volunteer observers. A 39.4 kIn roadside survey route is driven starting 30 min before sunrise, and a 3 min point count is conducted at each of 50 stops spaced every 0.8 kIn. Existing analyses of the data are internet-based (http://www.mbr-pwrc.usgs.govlbbslbbs.html), and include maps of relative abundance, estimates of population change including trends (%/yr), composite annual indices (pattern in time), and maps of population trend (pattern in space). At least 36 species of marsh birds are encountered on the BBS, and the survey provides estimates with greatly varying levels of efficiency for the species. It is often difficult to understand how well the BBS surveys a species. Often, efficiency is judged by estimating trend and its variance for a species, then by calculating power and needed samples to detect a prespecified trend over some time period (e.g., a 2%/yr trend over 31 yr). Unfortunately, this approach is not always valid, as estimated trends and variances can be of little use if the population is poorly sampled. Lurking concerns with BBS data include (1) incomplete coverage of species range; (2) undersampling of habitats; and (3) low and variable visibility of birds during point counts. It is difficult to evaluate these concerns, because known populations do not exist for comparison with counts, and detection rates are time-consuming and costly to estimate. I evaluated the efficiency of the BBS for selected rails (Rallidae) and snipes (Scolopacidae), presenting estimates of population trend over 1966-1996 (T), power to detect 2%/yr trend over 31 yr, needed samples to achieve power of 0.75 with alpha= 0.1, number of survey routes with data for the species (N), average abundance on survey routes (RA), and maps of relative abundance. Examples include Yellow Rail (Coturnicops noveboracensis) (T=12 %/yr; P= 0.0085; N =28; routes; RA=0.05; Power=0.37; Needed samples=85), Black Rail (Laterallus jamaicensis) (No trend data or power information available, N =8), Clapper Rail (Rallus longirostris) (T=1.9%/yr; P=0.55; N =64; RA=0.31; Power=0.35; Needed samples=590), King Rail (Rallus elegans) (T=-4.2 %/yr; P= 0.03; N =76; Power=0.41; Needed samples=159), Sora (Porzana carolina) (T=0.98 %/yr; P= 0.24; N =720; RA= 0.92; Power=0.69; Needed samples= 377), and Common Snipe (Gallinago gallinago) (T=-0.24 %/yr; P= 0.54; N =1412; RA= 2.19; Power=0.98; Needed samples=205). With regard to quality of BBS data, marsh birds fall into 3 categories: (1) almost never encountered on BBS routes; (2) encountered at extremely low abundances on BBS routes; and (3) probably fairly well sampled by BBS roadside counts. BBS data can provide useful information for many marsh bird species, but users should be aware of the limitations of the BBS sample for monitoring species that have low visibility from point counts and prefer habitats not often encountered on roadsides.

Effects of sampling conditions on DNA-based estimates of American black bear abundance

USGS Publications Warehouse

Laufenberg, Jared S.; Van Manen, Frank T.; Clark, Joseph D.

2013-01-01

DNA-based capture-mark-recapture techniques are commonly used to estimate American black bear (Ursus americanus) population abundance (N). Although the technique is well established, many questions remain regarding study design. In particular, relationships among N, capture probability of heterogeneity mixtures A and B (pA and pB, respectively, or p, collectively), the proportion of each mixture (π), number of capture occasions (k), and probability of obtaining reliable estimates of N are not fully understood. We investigated these relationships using 1) an empirical dataset of DNA samples for which true N was unknown and 2) simulated datasets with known properties that represented a broader array of sampling conditions. For the empirical data analysis, we used the full closed population with heterogeneity data type in Program MARK to estimate N for a black bear population in Great Smoky Mountains National Park, Tennessee. We systematically reduced the number of those samples used in the analysis to evaluate the effect that changes in capture probabilities may have on parameter estimates. Model-averaged N for females and males were 161 (95% CI = 114–272) and 100 (95% CI = 74–167), respectively (pooled N = 261, 95% CI = 192–419), and the average weekly p was 0.09 for females and 0.12 for males. When we reduced the number of samples of the empirical data, support for heterogeneity models decreased. For the simulation analysis, we generated capture data with individual heterogeneity covering a range of sampling conditions commonly encountered in DNA-based capture-mark-recapture studies and examined the relationships between those conditions and accuracy (i.e., probability of obtaining an estimated N that is within 20% of true N), coverage (i.e., probability that 95% confidence interval includes true N), and precision (i.e., probability of obtaining a coefficient of variation ≤20%) of estimates using logistic regression. The capture probability for the larger of 2 mixture proportions of the population (i.e., pA or pB, depending on the value of π) was most important for predicting accuracy and precision, whereas capture probabilities of both mixture proportions (pA and pB) were important to explain variation in coverage. Based on sampling conditions similar to parameter estimates from the empirical dataset (pA = 0.30, pB = 0.05, N = 250, π = 0.15, and k = 10), predicted accuracy and precision were low (60% and 53%, respectively), whereas coverage was high (94%). Increasing pB, the capture probability for the predominate but most difficult to capture proportion of the population, was most effective to improve accuracy under those conditions. However, manipulation of other parameters may be more effective under different conditions. In general, the probabilities of obtaining accurate and precise estimates were best when p≥ 0.2. Our regression models can be used by managers to evaluate specific sampling scenarios and guide development of sampling frameworks or to assess reliability of DNA-based capture-mark-recapture studies.

Clouded leopard phylogeny revisited: support for species recognition and population division between Borneo and Sumatra

PubMed Central

Wilting, Andreas; Buckley-Beason, Valerie A; Feldhaar, Heike; Gadau, Jürgen; O'Brien, Stephen J; Linsenmair, K Eduard

2007-01-01

Background The clouded leopard (Neofelis nebulosa) is one of the least known cat species and depletion of their forested habitats puts it under heavy pressure. Recently reclassification of Bornean clouded leopards (N. nebulosa diardi) to species level (N.diardi) was suggested based on molecular and morphological evidence. Since the genetic results were based solely on three Bornean samples we re-evaluated this partition using additional samples of Bornean clouded leopards (N = 7) and we were also able to include specimens from Sumatra (N = 3), which were lacking in previous analysis. Results We found strong support for the distinction between N. nebulosa and N. diardi based on three fragments of mtDNA (900 bp) and 18 microsatellites. Forty-one fixed mitochondrial nucleotide differences and non-overlapping allele sizes in 8 of 18 microsatellite loci distinguished N. nebulosa and N. diardi. This is equivalent to the genetic divergence among recognized species in the genus Panthera. Sumatran clouded leopards clustered with specimens from Borneo, suggesting that Sumatran individuals also belong to N. diardi. Additionally, a significant population subdivision was apparent among N. diardi from Sumatra and Borneo based on mtDNA and microsatellite data. Conclusion Referring to their origin on two Sunda Islands we propose to give N. diardi the common name "Sundaland clouded leopard". The reduced gene flow between Borneo and Sumatra might suggest the recognition of two subspecies of N. diardi. Based on this reclassification of clouded leopards not only species, but also the populations on Borneo and Sumatra should be managed separately and a higher priority should be placed to protect the different populations from extinction. PMID:17535420

Genome-wide analysis of the diversity and ancestry of Korean dogs.

PubMed

Choi, Bong Hwan; Wijayananda, Hasini I; Lee, Soo Hyun; Lee, Doo Ho; Kim, Jong Seok; Oh, Seok Il; Park, Eung Woo; Lee, Cheul Koo; Lee, Seung Hwan

2017-01-01

There are various hypotheses on dog domestication based on archeological and genetic studies. Although many studies have been conducted on the origin of dogs, the existing literature about the ancestry, diversity, and population structure of Korean dogs is sparse. Therefore, this study is focused on the origin, diversity and population structure of Korean dogs. The study sample comprised four major categories, including non-dogs (coyotes and wolves), ancient, modern and Korean dogs. Selected samples were genotyped using an Illumina CanineHD array containing 173,662 single nucleotide polymorphisms. The genome-wide data were filtered using quality control parameters in PLINK 1.9. Only autosomal chromosomes were used for further analysis. The negative off-diagonal variance of the genetic relationship matrix analysis depicted, the variability of samples in each population. FIS (inbreeding rate within a population) values indicated, a low level of inbreeding within populations, and the patterns were in concordance with the results of Nei's genetic distance analysis. The lowest FST (inbreeding rate between populations) values among Korean and Chinese breeds, using a phylogenetic tree, multi-dimensional scaling, and a TreeMix likelihood tree showed Korean breeds are highly related to Chinese breeds. The Korean breeds possessed a unique and large diversity of admixtures compared with other breeds. The highest and lowest effective population sizes were observed in Korean Jindo Black (485) and Korean Donggyeong White (109), respectively. The historical effective population size of all Korean dogs showed declining trend from the past to present. It is important to take immediate action to protect the Korean dog population while conserving their diversity. Furthermore, this study suggests that Korean dogs have unique diversity and are one of the basal lineages of East Asian dogs, originating from China.

Genome-wide analysis of the diversity and ancestry of Korean dogs

PubMed Central

Lee, Doo Ho; Kim, Jong Seok; Oh, Seok Il; Park, Eung Woo; Lee, Cheul Koo; Lee, Seung Hwan

2017-01-01

There are various hypotheses on dog domestication based on archeological and genetic studies. Although many studies have been conducted on the origin of dogs, the existing literature about the ancestry, diversity, and population structure of Korean dogs is sparse. Therefore, this study is focused on the origin, diversity and population structure of Korean dogs. The study sample comprised four major categories, including non-dogs (coyotes and wolves), ancient, modern and Korean dogs. Selected samples were genotyped using an Illumina CanineHD array containing 173,662 single nucleotide polymorphisms. The genome-wide data were filtered using quality control parameters in PLINK 1.9. Only autosomal chromosomes were used for further analysis. The negative off-diagonal variance of the genetic relationship matrix analysis depicted, the variability of samples in each population. FIS (inbreeding rate within a population) values indicated, a low level of inbreeding within populations, and the patterns were in concordance with the results of Nei’s genetic distance analysis. The lowest FST (inbreeding rate between populations) values among Korean and Chinese breeds, using a phylogenetic tree, multi-dimensional scaling, and a TreeMix likelihood tree showed Korean breeds are highly related to Chinese breeds. The Korean breeds possessed a unique and large diversity of admixtures compared with other breeds. The highest and lowest effective population sizes were observed in Korean Jindo Black (485) and Korean Donggyeong White (109), respectively. The historical effective population size of all Korean dogs showed declining trend from the past to present. It is important to take immediate action to protect the Korean dog population while conserving their diversity. Furthermore, this study suggests that Korean dogs have unique diversity and are one of the basal lineages of East Asian dogs, originating from China. PMID:29182674

Considering the needs of English language learner populations: an examination of the population validity of reading intervention research.

PubMed

Moore, Brooke A; Klingner, Janette K

2014-01-01

This article synthesizes reading intervention research studies intended for use with struggling or at-risk students to determine which studies adequately address population validity, particularly in regard to the diverse reading needs of English language learners. An extensive search of the professional literature between 2001 and 2010 yielded a total of 67 reading intervention studies targeting at-risk elementary students. Findings revealed that many current research studies fail to adequately describe the sample, including the accessible and target populations, and to disaggregate their findings based on demographic characteristics. When population validity issues are not addressed, researchers cannot generalize findings to other populations of students, and it becomes unclear what intervention strategies work, especially with English language learner student populations. However, 25 studies did specifically recognize and address the needs of English language learners, indicating more researchers are taking into consideration the diverse needs of other struggling student populations. © Hammill Institute on Disabilities 2012.

Limits of Generalizing in Education Research: Why Criteria for Research Generalization Should Include Population Heterogeneity and Uses of Knowledge Claims

ERIC Educational Resources Information Center

Ercikan, Kadriye; Roth, Wolff-Michael

2014-01-01

Context: Generalization is a critical concept in all research designed to generate knowledge that applies to all elements of a unit (population) while studying only a subset of these elements (sample). Commonly applied criteria for generalizing focus on experimental design or representativeness of samples of the population of units. The criteria…

Parent-based diagnosis of ADHD is as accurate as a teacher-based diagnosis of ADHD.

PubMed

Bied, Adam; Biederman, Joseph; Faraone, Stephen

2017-04-01

To review the literature evaluating the psychometric properties of parent and teacher informants relative to a gold-standard ADHD diagnosis in pediatric populations. We included studies that included both a parent and teacher informant, a gold-standard diagnosis, and diagnostic accuracy metrics. Potential confounds were evaluated. We also assessed the 'OR' and the 'AND' rules for combining informant reports. Eight articles met inclusion criteria. The diagnostic accuracy for predicting gold standard ADHD diagnoses did not differ between parents and teachers. Sample size, sample type, participant drop-out, participant age, participant gender, geographic area of the study, and date of study publication were assessed as potential confounds. Parent and teachers both yielded moderate to good diagnostic accuracy for ADHD diagnoses. Parent reports were statistically indistinguishable from those of teachers. The predictive features of the 'OR' and 'AND' rules are useful in evaluating approaches to better integrating information from these informants.

The Generation R Study: Biobank update 2015.

PubMed

Kruithof, Claudia J; Kooijman, Marjolein N; van Duijn, Cornelia M; Franco, Oscar H; de Jongste, Johan C; Klaver, Caroline C W; Mackenbach, Johan P; Moll, Henriëtte A; Raat, Hein; Rings, Edmond H H M; Rivadeneira, Fernando; Steegers, Eric A P; Tiemeier, Henning; Uitterlinden, Andre G; Verhulst, Frank C; Wolvius, Eppo B; Hofman, Albert; Jaddoe, Vincent W V

2014-12-01

The Generation R Study is a population-based prospective cohort study from fetal life until adulthood. The study is designed to identify early environmental and genetic causes and causal pathways leading to normal and abnormal growth, development and health from fetal life, childhood and young adulthood. In total, 9,778 mothers were enrolled in the study. Data collection in children and their parents include questionnaires, interviews, detailed physical and ultrasound examinations, behavioural observations, Magnetic Resonance Imaging and biological samples. Efforts have been conducted for collecting biological samples including blood, hair, faeces, nasal swabs, saliva and urine samples and generating genomics data on DNA, RNA and microbiome. In this paper, we give an update of the collection, processing and storage of these biological samples and available measures. Together with detailed phenotype measurements, these biological samples provide a unique resource for epidemiological studies focused on environmental exposures, genetic and genomic determinants and their interactions in relation to growth, health and development from fetal life onwards.

Gaps in Survey Data on Cancer in American Indian and Alaska Native Populations: Examination of US Population Surveys, 1960–2010

PubMed Central

Duran, Tinka; Stimpson, Jim P.; Smith, Corey

2013-01-01

Introduction Population-based data are essential for quantifying the problems and measuring the progress made by comprehensive cancer control programs. However, cancer information specific to the American Indian/Alaska Native (AI/AN) population is not readily available. We identified major population-based surveys conducted in the United States that contain questions related to cancer, documented the AI/AN sample size in these surveys, and identified gaps in the types of cancer-related information these surveys collect. Methods We conducted an Internet query of US Department of Health and Human Services agency websites and a Medline search to identify population-based surveys conducted in the United States from 1960 through 2010 that contained information about cancer. We used a data extraction form to collect information about the purpose, sample size, data collection methods, and type of information covered in the surveys. Results Seventeen survey sources met the inclusion criteria. Information on access to and use of cancer treatment, follow-up care, and barriers to receiving timely and quality care was not consistently collected. Estimates specific to the AI/AN population were often lacking because of inadequate AI/AN sample size. For example, 9 national surveys reviewed reported an AI/AN sample size smaller than 500, and 10 had an AI/AN sample percentage less than 1.5%. Conclusion Continued efforts are needed to increase the overall number of AI/AN participants in these surveys, improve the quality of information on racial/ethnic background, and collect more information on treatment and survivorship. PMID:23517582

A comparison of temporal and location-based sampling strategies for global positioning system-triggered electronic diaries.

PubMed

Törnros, Tobias; Dorn, Helen; Reichert, Markus; Ebner-Priemer, Ulrich; Salize, Hans-Joachim; Tost, Heike; Meyer-Lindenberg, Andreas; Zipf, Alexander

2016-11-21

Self-reporting is a well-established approach within the medical and psychological sciences. In order to avoid recall bias, i.e. past events being remembered inaccurately, the reports can be filled out on a smartphone in real-time and in the natural environment. This is often referred to as ambulatory assessment and the reports are usually triggered at regular time intervals. With this sampling scheme, however, rare events (e.g. a visit to a park or recreation area) are likely to be missed. When addressing the correlation between mood and the environment, it may therefore be beneficial to include participant locations within the ambulatory assessment sampling scheme. Based on the geographical coordinates, the database query system then decides if a self-report should be triggered or not. We simulated four different ambulatory assessment sampling schemes based on movement data (coordinates by minute) from 143 voluntary participants tracked for seven consecutive days. Two location-based sampling schemes incorporating the environmental characteristics (land use and population density) at each participant's location were introduced and compared to a time-based sampling scheme triggering a report on the hour as well as to a sampling scheme incorporating physical activity. We show that location-based sampling schemes trigger a report less often, but we obtain more unique trigger positions and a greater spatial spread in comparison to sampling strategies based on time and distance. Additionally, the location-based methods trigger significantly more often at rarely visited types of land use and less often outside the study region where no underlying environmental data are available.

Operationalizing multimorbidity and autonomy for health services research in aging populations - the OMAHA study

PubMed Central

2011-01-01

Background As part of a Berlin-based research consortium on health in old age, the OMAHA (Operationalizing Multimorbidity and Autonomy for Health Services Research in Aging Populations) study aims to develop a conceptual framework and a set of standardized instruments and indicators for continuous monitoring of multimorbidity and associated health care needs in the population 65 years and older. Methods/Design OMAHA is a longitudinal epidemiological study including a comprehensive assessment at baseline and at 12-month follow-up as well as brief intermediate telephone interviews at 6 and 18 months. In order to evaluate different sampling procedures and modes of data collection, the study is conducted in two different population-based samples of men and women aged 65 years and older. A geographically defined sample was recruited from an age and sex stratified random sample from the register of residents in Berlin-Mitte (Berlin OMAHA study cohort, n = 299) for assessment by face-to-face interview and examination. A larger nationwide sample (German OMAHA study cohort, n = 730) was recruited for assessment by telephone interview among participants in previous German Telephone Health Surveys. In both cohorts, we successfully applied a multi-dimensional set of instruments to assess multimorbidity, functional disability in daily life, autonomy, quality of life (QoL), health care services utilization, personal and social resources as well as socio-demographic and biographical context variables. Response rates considerably varied between the Berlin and German OMAHA study cohorts (22.8% vs. 59.7%), whereas completeness of follow-up at month 12 was comparably high in both cohorts (82.9% vs. 81.2%). Discussion The OMAHA study offers a wide spectrum of data concerning health, functioning, social involvement, psychological well-being, and cognitive capacity in community-dwelling older people in Germany. Results from the study will add to methodological and content-specific discourses on human resources for maintaining quality of life and autonomy throughout old age, even in the face of multiple health complaints. PMID:21352521

Seasonal Variability of Salt Marsh Foraminifera at the Narrow River, Rhode Island, USA

NASA Astrophysics Data System (ADS)

Amelse, C. M.; Engelhart, S. E.; Halavik, B.; Kemp, A.

2016-12-01

Salt-marsh foraminifera are commonly used as proxies for producing high-resolution relative sea-level reconstructions over the Holocene. These reconstructions are based on the analogy between modern and fossil assemblages of foraminifera, in which modern assemblages were characterized using surface sediment samples collected on a single day. This approach implicitly assumes that instantaneous sampling of modern salt-marsh foraminifera is adequate to characterize the relationship between foraminiferal assemblages and tidal elevation. However, foraminiferal populations may vary during a year in response to seasonal changes, which may affect the reliability of relative sea-level reconstructions. The effect of seasonality on salt marsh foraminiferal populations has been studied in the United Kingdom as well as on the Pacific coast of the USA, but is absent on the Atlantic coast of the USA. To address this, we investigated the role of seasonality on foraminiferal distributions from a salt marsh environment at the Narrow River (Rhode Island, USA). We analyzed living and dead foraminiferal species from 48 samples through a full year during all four seasons. Common species included Trochammina inflata, Jadammina macrescens, Tiphotrocha comprimata, Miliammina fusca, Reophax spp., and Haplophragmoides spp. Other species included Siphotrochammina lobata, Arenoparella mexicana, Textularia spp., Ammobaculites spp., and Eggerella advena. Low marsh samples were dominated by Miliammina fusca and Reophax spp., while high marsh samples are identified by high abundances of Haplophragmoides spp. Statistical analyses of these samples enables us to identify the influence of seasonality on modern foraminiferal distributions.

Evaluation of European Schizophrenia GWAS Loci in Asian Populations via Comprehensive Meta-Analyses.

PubMed

Xiao, Xiao; Luo, Xiong-Jian; Chang, Hong; Liu, Zichao; Li, Ming

2017-08-01

Schizophrenia is a severe and highly heritable neuropsychiatric disorder. Recent genetic analyses including genome-wide association studies (GWAS) have implicated multiple genome-wide significant variants for schizophrenia among European populations. However, many of these risk variants were not largely validated in other populations of different ancestry such as Asians. To validate whether these European GWAS significant loci are associated with schizophrenia in Asian populations, we conducted a systematic literature search and meta-analyses on 19 single nucleotide polymorphisms (SNPs) in Asian populations by combining all available case-control and family-based samples, including up to 30,000 individuals. We employed classical fixed (or random) effects inverse variance weighted methods to calculate summary odds ratios (ORs) and 95 % confidence intervals (CIs). Among the 19 GWAS loci, we replicated the risk associations of nine markers (e.g., SNPs at VRK2, ITIH3/4, NDST3, NOTCH4) surpassing significance level (two-tailed P < 0.05), and three additional SNPs in MIR137 and ZNF804A also showed trend associations (one-tailed P < 0.05). These risk associations are in the same directions of allelic effects between Asian replication samples and initial European GWAS findings, and the successful replications of these GWAS loci in a different ethnic group provide stronger evidence for their clinical associations with schizophrenia. Further studies, focusing on the molecular mechanisms of these GWAS significant loci, will become increasingly important for understanding of the pathogenesis to schizophrenia.

Six rapid assessments of alcohol and other substance use in populations displaced by conflict

PubMed Central

2011-01-01

Background Substance use among populations displaced by conflict is a neglected area of public health. Alcohol, khat, benzodiazepine, opiate, and other substance use have been documented among a range of displaced populations, with wide-reaching health and social impacts. Changing agendas in humanitarian response-including increased prominence of mental health and chronic illness-have so far failed to be translated into meaningful interventions for substance use. Methods Studies were conducted from 2006 to 2008 in six different settings of protracted displacement, three in Africa (Kenya, Liberia, northern Uganda) and three in Asia (Iran, Pakistan, and Thailand). We used intervention-oriented qualitative Rapid Assessment and Response methods, adapted from two decades of experience among non-displaced populations. The main sources of data were individual and group interviews conducted with a culturally representative (non-probabilistic) sample of community members and service providers. Results Widespread use of alcohol, particularly artisanally-produced alcohol, in Kenya, Liberia, Uganda, and Thailand, and opiates in Iran and Pakistan was believed by participants to be linked to a range of health, social and protection problems, including illness, injury (intentional and unintentional), gender-based violence, risky behaviour for HIV and other sexually transmitted infection and blood-borne virus transmission, as well as detrimental effects to household economy. Displacement experiences, including dispossession, livelihood restriction, hopelessness and uncertain future may make communities particularly vulnerable to substance use and its impact, and changing social norms and networks (including the surrounding population) may result in changed - and potentially more harmful-patterns of use. Limited access to services, including health services, and exclusion from relevant host population programmes, may exacerbate the harmful consequences. Conclusions The six studies show the feasibility and value of conducting rapid assessments in displaced populations. One outcome of these studies is the development of a UNHCR/WHO field guide on rapid assessment of alcohol and other substance use among conflict-affected populations. More work is required on gathering population-based epidemiological data, and much more experience is required on delivering effective interventions. Presentation of these findings should contribute to increased awareness, improved response, and more vigorous debate around this important but neglected area. PMID:21310092

Usefulness of autosomal STR polymorphisms beyond forensic purposes: data on Arabic- and Berber-speaking populations from central Morocco.

PubMed

Gaibar, Maria; Esteban, María Esther; Via, Marc; Harich, Nourdin; Kandil, Mostafa; Fernández-Santander, Ana

2012-07-01

This work describes, for the first time, the profile of Middle Atlas Berbers and Arabic-speaking central Moroccans for 15 autosomal STR loci widely used in forensic sciences. The main objectives were to determine the degree of heterogeneity among different Moroccan samples to identify geographic or linguistic patterns and to evaluate the usefulness of forensic STRs in anthropological studies. Blood samples were collected from 71 Arabic-speakers and 75 Berbers from the regions of Doukkala (central-west coast) and Khenifra (Middle Atlas), respectively. The AmpFlSTR Identifier kit was used to genotype 15 autosomal STR in both samples. Middle Atlas Berbers showed slightly higher genetic variation values compared to Arabic-speakers, both in the number of alleles and heterozygosity. In order to assess population relationships, data from Morocco, Algeria, Tunisia, Libya, Egypt, Kuwait, Qatar, Palestine, Syria, South-Spain and Turkey were included in the analysis. Within Morocco, genetic distances followed a clear geographic pattern. In the Arabic-speaking sample the genetic proportion of 'Arabian' admixture was estimated in 13%. The low value of admixture suggests that the Arabization of Morocco had a reduced demographic impact, which should be taken with caution because it is based on autosomal STRs with low inter-population variation levels.

kWIP: The k-mer weighted inner product, a de novo estimator of genetic similarity.

PubMed

Murray, Kevin D; Webers, Christfried; Ong, Cheng Soon; Borevitz, Justin; Warthmann, Norman

2017-09-01

Modern genomics techniques generate overwhelming quantities of data. Extracting population genetic variation demands computationally efficient methods to determine genetic relatedness between individuals (or "samples") in an unbiased manner, preferably de novo. Rapid estimation of genetic relatedness directly from sequencing data has the potential to overcome reference genome bias, and to verify that individuals belong to the correct genetic lineage before conclusions are drawn using mislabelled, or misidentified samples. We present the k-mer Weighted Inner Product (kWIP), an assembly-, and alignment-free estimator of genetic similarity. kWIP combines a probabilistic data structure with a novel metric, the weighted inner product (WIP), to efficiently calculate pairwise similarity between sequencing runs from their k-mer counts. It produces a distance matrix, which can then be further analysed and visualised. Our method does not require prior knowledge of the underlying genomes and applications include establishing sample identity and detecting mix-up, non-obvious genomic variation, and population structure. We show that kWIP can reconstruct the true relatedness between samples from simulated populations. By re-analysing several published datasets we show that our results are consistent with marker-based analyses. kWIP is written in C++, licensed under the GNU GPL, and is available from https://github.com/kdmurray91/kwip.

Bias of health estimates obtained from chronic disease and risk factor surveillance systems using telephone population surveys in Australia: results from a representative face-to-face survey in Australia from 2010 to 2013.

PubMed

Dal Grande, Eleonora; Chittleborough, Catherine R; Campostrini, Stefano; Taylor, Anne W

2016-04-18

Emerging communication technologies have had an impact on population-based telephone surveys worldwide. Our objective was to examine the potential biases of health estimates in South Australia, a state of Australia, obtained via current landline telephone survey methodologies and to report on the impact of mobile-only household on household surveys. Data from an annual multi-stage, systematic, clustered area, face-to-face population survey, Health Omnibus Survey (approximately 3000 interviews annually), included questions about telephone ownership to assess the population that were non-contactable by current telephone sampling methods (2006 to 2013). Univariable analyses (2010 to 2013) and trend analyses were conducted for sociodemographic and health indicator variables in relation to telephone status. Relative coverage biases (RCB) of two hypothetical telephone samples was undertaken by examining the prevalence estimates of health status and health risk behaviours (2010 to 2013): directory-listed numbers, consisting mainly of landline telephone numbers and a small proportion of mobile telephone numbers; and a random digit dialling (RDD) sample of landline telephone numbers which excludes mobile-only households. Telephone (landline and mobile) coverage in South Australia is very high (97%). Mobile telephone ownership increased slightly (7.4%), rising from 89.7% in 2006 to 96.3% in 2013; mobile-only households increased by 431% over the eight year period from 5.2% in 2006 to 27.6% in 2013. Only half of the households have either a mobile or landline number listed in the telephone directory. There were small differences in the prevalence estimates for current asthma, arthritis, diabetes and obesity between the hypothetical telephone samples and the overall sample. However, prevalence estimate for diabetes was slightly underestimated (RCB value of -0.077) in 2013. Mixed RCB results were found for having a mental health condition for both telephone samples. Current smoking prevalence was lower for both hypothetical telephone samples in absolute differences and RCB values: -0.136 to -0.191 for RDD landline samples and -0.129 to -0.313 for directory-listed samples. These findings suggest landline-based sampling frames used in Australia, when appropriately weighted, produce reliable representative estimates for some health indicators but not for all. Researchers need to be aware of their limitations and potential biased estimates.

Sampling Methods in Cardiovascular Nursing Research: An Overview.

PubMed

Kandola, Damanpreet; Banner, Davina; O'Keefe-McCarthy, Sheila; Jassal, Debbie

2014-01-01

Cardiovascular nursing research covers a wide array of topics from health services to psychosocial patient experiences. The selection of specific participant samples is an important part of the research design and process. The sampling strategy employed is of utmost importance to ensure that a representative sample of participants is chosen. There are two main categories of sampling methods: probability and non-probability. Probability sampling is the random selection of elements from the population, where each element of the population has an equal and independent chance of being included in the sample. There are five main types of probability sampling including simple random sampling, systematic sampling, stratified sampling, cluster sampling, and multi-stage sampling. Non-probability sampling methods are those in which elements are chosen through non-random methods for inclusion into the research study and include convenience sampling, purposive sampling, and snowball sampling. Each approach offers distinct advantages and disadvantages and must be considered critically. In this research column, we provide an introduction to these key sampling techniques and draw on examples from the cardiovascular research. Understanding the differences in sampling techniques may aid nurses in effective appraisal of research literature and provide a reference pointfor nurses who engage in cardiovascular research.

Polymerase chain reaction-based detection of B-cell monoclonality in cytologic specimens.

PubMed

Chen, Y T; Mercer, G O; Chen, Y

1993-11-01

Thirty-seven cytologic cell blocks were evaluated for B-cell monoclonality by polymerase chain reaction (PCR), 16 of them cytologically positive for lymphoma, and 21 suspicious for lymphoma but morphologically nondiagnostic. Of 37 specimens, 13 (35%) showed B-cell monoclonality, including six of 16 cytologically positive samples and seven of 21 cytologically suspicious ones. Of these 13 positive samples, seven were positive using crude lysates as substrates, and six additional positive samples were identified only when DNAs were purified and concentrated. Analysis of the DNAs further revealed poor polymerase chain reaction amplifiability and low DNA yield in many samples, indicating that cell block materials are suboptimal for this assay. We concluded that B-cell monoclonality can be detected in ethanol-fixed cytologic samples, and usage of unembedded material will likely improve the sensitivity. In specimens cytologically suspicious for lymphoma, polymerase chain reaction-based identification of monoclonal B-cell population supports the diagnosis of B-cell lymphoma and is a potentially useful test in solving this diagnostic dilemma.

Prevalence of depression: Comparisons of different depression definitions in population-based samples of older adults.

PubMed

Sjöberg, Linnea; Karlsson, Björn; Atti, Anna-Rita; Skoog, Ingmar; Fratiglioni, Laura; Wang, Hui-Xin

2017-10-15

Depression prevalence in older adults varies largely across studies, which probably reflects methodological rather than true differences. This study aims to explore whether and to what extent the prevalence of depression varies when using different diagnostic criteria and rating scales, and various samples of older adults. A population-based sample of 3353 individuals aged 60-104 years from the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K) were examined in 2001-2004. Point prevalence of depression was estimated by: 1) diagnostic criteria, ICD-10 and DSM-IV-TR/DSM-5; 2) rating scales, MADRS and GDS-15; and 3) self-report. Depression prevalence in sub-samples by dementia status, living place, and socio-demographics were compared. The prevalence of any depression (including all severity grades) was 4.2% (moderate/severe: 1.6%) for ICD-10 and 9.3% (major: 2.1%) for DSM-IV-TR; 10.6% for MADRS and 9.2% for GDS-15; and 9.1% for self-report. Depression prevalence was lower in the dementia-free sample as compared to the total population. Furthermore, having poor physical function, or not having a partner were independently associated with higher depression prevalence, across most of the depression definitions. The response rate was 73.3% and this may have resulted in an underestimation of depression. Depression prevalence was similar across all depression definitions except for ICD-10, showing much lower figures. However, independent of the definition used, depression prevalence varies greatly by dementia status, physical functioning, and marital status. These findings may be useful for clinicians when assessing depression in older adults and for researchers when exploring and comparing depression prevalence across studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Smoking relapse situations among a community-recruited sample of Spanish daily smokers.

PubMed

Piñeiro, Bárbara; López-Durán, Ana; Martínez-Vispo, Carmela; Fernández Del Río, Elena; Martínez, Úrsula; Rodríguez-Cano, Rubén; Míguez, M Carmen; Becoña, Elisardo

2017-12-01

Relapse is a common factor within the behavior change process. However, there is scarce and limited knowledge of smoking relapse situations in population-based samples. The aim of this study was to identify smoking relapse situations among a sample of Spanish relapsers from the general population. A sample of 775 relapsers was recruited among the general population using a snowball method. Participants completed a survey including sociodemographic, smoking-related and psychopathology variables. Smoking relapse situations were identified through specific questions assessing different aspects related to the last relapse episode. The majority of smoking relapse situations were attributed to positive affect (36.6%) and negative affect (34.3%), followed by lack of control (10.1%), smoking habit (6.7%), craving or nicotine withdrawal (6.3%), and social pressure (5.9%). Being unemployed and having a mental disorder in the past increased the likelihood of relapse in situations of negative affect. Being single and having quit smoking to save money were associated with an increased likelihood of relapse in situations of positive affect. Affect plays a significant role in smoking relapse among a community sample of unassisted Spanish smokers. Relapse may be much more of an affective and situational process than a habit, physiological or social pressure. Findings from this study may help develop tailored community smoking relapse prevention strategies or programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gradient-free MCMC methods for dynamic causal modelling.

PubMed

Sengupta, Biswa; Friston, Karl J; Penny, Will D

2015-05-15

In this technical note we compare the performance of four gradient-free MCMC samplers (random walk Metropolis sampling, slice-sampling, adaptive MCMC sampling and population-based MCMC sampling with tempering) in terms of the number of independent samples they can produce per unit computational time. For the Bayesian inversion of a single-node neural mass model, both adaptive and population-based samplers are more efficient compared with random walk Metropolis sampler or slice-sampling; yet adaptive MCMC sampling is more promising in terms of compute time. Slice-sampling yields the highest number of independent samples from the target density - albeit at almost 1000% increase in computational time, in comparison to the most efficient algorithm (i.e., the adaptive MCMC sampler). Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

The epidemiological information system of the French national electricity and gas company: the SI-EPI project.

PubMed

Goldberg, M; Chevalier, A; Imbernon, E; Coing, F; Pons, H

1996-01-01

SI-EPI is epidemiological information system set up in 1978 in the national electricity and gas company, Electricité de France-Gaz de France (EDF-GDF). The worker population comprises about 150,000 individuals, involved in production, transmission and distribution of energy. SI-EPI was developed by the epidemiologists of the Occupational Health Department (180 physicians), and of the Sécurité Sociale Department (120 physicians). Several data bases constitute SI-EPI. The population data base contains demographic, socioeconomic and professional data about each worker. The health data base is an exhaustive register of sick leave, accidents, permanent disabilities, compensated diseases, causes of death and cancer incidence among active workers. The Occupational Exposure and Working Conditions data base includes the MATEX job-exposure matrix (30 potentially carcinogenic agents) and FINDEX files which record data obtained from the systematic individual surveillance of workers. The GAZEL cohort data base concerns a sample of more than 20,000 volunteer workers, followed since 1989; in addition to data from the data bases, it contains information collected from other different sources, including self-questionnaires. Numerous epidemiological studies based on SI-EPI data have been conducted by in-house epidemiologists as well as by external research groups. They include mortality and morbidity studies and address various topics and health problems. Their results are used for internal information, as well as for epidemiological research purposes.

Substance Abuse Among Blacks Across the Diaspora

PubMed Central

Lacey, Krim K.; Mouzon, Dawne M.; Govia, Ishtar O.; Matusko, Niki; Forsythe-Brown, Ivy; Abelson, Jamie M.; Jackson, James S.

2016-01-01

Background Lower rates of substance abuse are found among Black Americans compared to Whites, but little is known about differences in substance abuse across ethnic groups within the black population. Objectives We examined prevalence rates of substance abuse among Blacks across three geographic regions (US, Jamaica, Guyana). The study also sought to ascertain whether length of time, national context and major depressive episodes (MDE) were associated with substance abuse. Methods We utilized three different data sources based upon probability samples collected in three different countries. The samples included 3,570 African Americans and 1,621 US Caribbean Black adults from the 2001–2003 National Survey of American Life (NSAL). An additional 1,142 Guyanese Blacks and 1,176 Jamaican Blacks living in the Caribbean region were included from the 2005 NSAL replication extension study, Family Connections Across Generations and Nations (FCGN). Mental disorders were based upon DSM-IV criteria. For the analysis, we used descriptive statistics, chi-square, and multivariate logistic regression analytic procedures. Results Prevalence of substance abuse varied by national context, with higher rates among Blacks within the United States compared to the Caribbean region. Rates of substance abuse were lower overall for women, but differ across cohorts by nativity and length of time in the United States, and in association with major depressive episode. Conclusions The study highlights the need for further examination of how substance abuse disparities between US-based and Caribbean-based populations may become manifested. PMID:27191862

Validity of a computerized population registry of dementia based on clinical databases.

PubMed

Mar, J; Arrospide, A; Soto-Gordoa, M; Machón, M; Iruin, Á; Martinez-Lage, P; Gabilondo, A; Moreno-Izco, F; Gabilondo, A; Arriola, L

2018-05-08

The handling of information through digital media allows innovative approaches for identifying cases of dementia through computerized searches within the clinical databases that include systems for coding diagnoses. The aim of this study was to analyze the validity of a dementia registry in Gipuzkoa based on the administrative and clinical databases existing in the Basque Health Service. This is a descriptive study based on the evaluation of available data sources. First, through review of medical records, the diagnostic validity was evaluated in 2 samples of cases identified and not identified as dementia. The sensitivity, specificity and positive and negative predictive value of the diagnosis of dementia were measured. Subsequently, the cases of living dementia in December 31, 2016 were searched in the entire Gipuzkoa population to collect sociodemographic and clinical variables. The validation samples included 986 cases and 327 no cases. The calculated sensitivity was 80.2% and the specificity was 99.9%. The negative predictive value was 99.4% and positive value was 95.1%. The cases in Gipuzkoa were 10,551, representing 65% of the cases predicted according to the literature. Antipsychotic medication were taken by a 40% and a 25% of the cases were institutionalized. A registry of dementias based on clinical and administrative databases is valid and feasible. Its main contribution is to show the dimension of dementia in the health system. Copyright © 2018 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

Systematic review of the use of online questionnaires of older adults.

PubMed

Remillard, Meegan L; Mazor, Kathleen M; Cutrona, Sarah L; Gurwitz, Jerry H; Tjia, Jennifer

2014-04-01

To describe methodological approaches to population targeting and sampling and to summarize limitations of Internet-based questionnaires in older adults. Systematic literature review. Studies using online questionnaires in older adult populations. English-language articles using search terms for geriatric, age 65 and over, Internet survey, online survey, Internet questionnaire, and online questionnaire in PubMed and EBSCO host between 1984 and July 2012. Inclusion criteria were study population mean age 65 and older and use of an online questionnaire for research. Review of 336 abstracts yielded 14 articles for full review by two investigators; 11 articles met inclusion criteria. Articles were extracted for study design and setting, participant characteristics, recruitment strategy, country, and study limitations. Eleven articles were published after 2001. Studies had populations with a mean age of 65 to 78, included descriptive and analytical designs, and were conducted in the United States, Australia, and Japan. Recruiting methods varied widely from paper fliers and personal e-mails to use of consumer marketing panels. Investigator-reported study limitations included the use of small convenience samples and limited generalizability. Online questionnaires are a feasible method of surveying older adults in some geographic regions and for some subsets of older adults, but limited Internet access constrains recruiting methods and often limits study generalizability. © 2014, Copyright the Authors Journal compilation © 2014, The American Geriatrics Society.

SNP-based heritability estimates of the personality dimensions and polygenic prediction of both neuroticism and major depression: findings from CONVERGE.

PubMed

Docherty, A R; Moscati, A; Peterson, R; Edwards, A C; Adkins, D E; Bacanu, S A; Bigdeli, T B; Webb, B T; Flint, J; Kendler, K S

2016-10-25

Biometrical genetic studies suggest that the personality dimensions, including neuroticism, are moderately heritable (~0.4 to 0.6). Quantitative analyses that aggregate the effects of many common variants have recently further informed genetic research on European samples. However, there has been limited research to date on non-European populations. This study examined the personality dimensions in a large sample of Han Chinese descent (N=10 064) from the China, Oxford, and VCU Experimental Research on Genetic Epidemiology study, aimed at identifying genetic risk factors for recurrent major depression among a rigorously ascertained cohort. Heritability of neuroticism as measured by the Eysenck Personality Questionnaire (EPQ) was estimated to be low but statistically significant at 10% (s.e.=0.03, P=0.0001). In addition to EPQ, neuroticism based on a three-factor model, data for the Big Five (BF) personality dimensions (neuroticism, openness, conscientiousness, extraversion and agreeableness) measured by the Big Five Inventory were available for controls (n=5596). Heritability estimates of the BF were not statistically significant despite high power (>0.85) to detect heritabilities of 0.10. Polygenic risk scores constructed by best linear unbiased prediction weights applied to split-half samples failed to significantly predict any of the personality traits, but polygenic risk for neuroticism, calculated with LDpred and based on predictive variants previously identified from European populations (N=171 911), significantly predicted major depressive disorder case-control status (P=0.0004) after false discovery rate correction. The scores also significantly predicted EPQ neuroticism (P=6.3 × 10 -6 ). Factor analytic results of the measures indicated that any differences in heritabilities across samples may be due to genetic variation or variation in haplotype structure between samples, rather than measurement non-invariance. Findings demonstrate that neuroticism can be significantly predicted across ancestry, and highlight the importance of studying polygenic contributions to personality in non-European populations.

How Generalizable Is Your Experiment? An Index for Comparing Experimental Samples and Populations

ERIC Educational Resources Information Center

Tipton, Elizabeth

2014-01-01

Although a large-scale experiment can provide an estimate of the average causal impact for a program, the sample of sites included in the experiment is often not drawn randomly from the inference population of interest. In this article, we provide a generalizability index that can be used to assess the degree of similarity between the sample of…

Microsatellite-based genetic diversity patterns in disjunct populations of a rare orchid.

PubMed

Pandey, Madhav; Richards, Matt; Sharma, Jyotsna

2015-12-01

We investigated the patterns of genetic diversity and structure in seven disjunct populations of a rare North American orchid, Cypripedium kentuckiense by including populations that represented the periphery and the center of the its range. Eight nuclear and two chloroplast microsatellites were used. Genetic diversity was low across the sampled populations of C. kentuckiense based on both nuclear (average An = 4.0, Ho = 0.436, He = 0.448) and cpDNA microsatellites (average An = 1.57, Nh = 1.57 and H = 0.133). The number of private alleles ranged from one to four per population with a total of 17 private alleles detected at five nuclear microsatellites. One private allele at one cpDNA microsatellite was also observed. Although the absolute values for nuclear microsatellite based population differentiation were low (Fst = 0.075; ϕPT = 0.24), they were statistically significant. Pairwise Fst values ranged from 0.038 to 0.123 and each comparison was significant. We also detected isolation by distance with nDNA microsatellites based on the Mantel test (r(2) = 0.209, P = 0.05). STRUCTURE analysis and the neighbor joining trees grouped the populations similarly whereby the geographically proximal populations were genetically similar. Our data indicate that the species is genetically depauperate but the diversity is distributed more or less equally across its range. Population differentiation and isolation by distance were detectable, which indicates that genetic isolation is beginning to manifest itself across the range in this rare species.

Monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm on permanent plots: sampling methods and statistical properties of data

Treesearch

A.R. Mason; H.G. Paul

1994-01-01

Procedures for monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience in sampling these species in eastern Oregon and Washington. It is shown that statistically reliable estimates of larval density can be made for a population by sampling host trees in a series of permanent plots in a...

Comparison of Online Survey Recruitment Platforms for Hard-to-Reach Pregnant Smoking Populations: Feasibility Study.

PubMed

Ibarra, Jose Luis; Agas, Jessica Marie; Lee, Melissa; Pan, Julia Lily; Buttenheim, Alison Meredith

2018-04-16

Recruiting hard-to-reach populations for health research is challenging. Web-based platforms offer one way to recruit specific samples for research purposes, but little is known about the feasibility of online recruitment and the representativeness and comparability of samples recruited through different Web-based platforms. The objectives of this study were to determine the feasibility of recruiting a hard-to-reach population (pregnant smokers) using 4 different Web-based platforms and to compare participants recruited through each platform. A screener and survey were distributed online through Qualtrics Panel, Soapbox Sample, Reddit, and Amazon Mechanical Turk (mTurk). Descriptive statistics were used to summarize results of each recruitment platform, including eligibility yield, quality yield, income, race, age, and gestational age. Of the 3847 participants screened for eligibility across all 4 Web-based platforms, 535 were eligible and 308 completed the survey. Amazon mTurk yielded the fewest completed responses (n=9), 100% (9/9) of which passed several quality metrics verifying pregnancy and smoking status. Qualtrics Panel yielded 14 completed responses, 86% (12/14) of which passed the quality screening. Soapbox Sample produced 107 completed surveys, 67% (72/107) of which were found to be quality responses. Advertising through Reddit produced the highest completion rate (n=178), but only 29.2% (52/178) of those surveys passed the quality metrics. We found significant differences in eligibility yield, quality yield, age, number of previous pregnancies, age of smoking initiation, current smokers, race, education, and income (P<.001). Although each platform successfully recruited pregnant smokers, results varied in quality, cost, and percentage of complete responses. Moving forward, investigators should pay careful attention to the percentage yield and cost of online recruitment platforms to maximize internal and external validity. ©Jose Luis Ibarra, Jessica Marie Agas, Melissa Lee, Julia Lily Pan, Alison Meredith Buttenheim. Originally published in JMIR Research Protocols (http://www.researchprotocols.org), 16.04.2018.

Sampling Migrants from their Social Networks: The Demography and Social Organization of Chinese Migrants in Dar es Salaam, Tanzania.

PubMed

Merli, M Giovanna; Verdery, Ashton; Mouw, Ted; Li, Jing

2016-07-01

The streams of Chinese migration to Africa are growing in tandem with rising Chinese investments and trade flows in and to the African continent. In spite of the high profile of this phenomenon in the media, there are few rich and broad descriptions of Chinese communities in Africa. Reasons for this include the rarity of official statistics on foreign-born populations in African censuses, the absence of predefined sampling frames required to draw representative samples with conventional survey methods and difficulties to reach certain segments of this population. Here, we use a novel network-based approach, Network Sampling with Memory, which overcomes the challenges of sampling 'hidden' populations in the absence of a sampling frame, to recruit a sample of recent Chinese immigrants in Dar es Salaam, Tanzania and collect information on the demographic characteristics, migration histories and social ties of members of this sample. These data reveal a heterogeneous Chinese community composed of "state-led" migrants who come to Africa to work on projects undertaken by large Chinese state-owned enterprises and "independent" migrants who come on their own accord to engage in various types of business ventures. They offer a rich description of the demographic profile and social organization of this community, highlight key differences between the two categories of migrants and map the structure of the social ties linking them. We highlight needs for future research on inter-group differences in individual motivations for migration, economic activities, migration outcomes, expectations about future residence in Africa, social integration and relations with local communities.

Sampling Migrants from their Social Networks: The Demography and Social Organization of Chinese Migrants in Dar es Salaam, Tanzania

PubMed Central

Merli, M. Giovanna; Verdery, Ashton; Mouw, Ted; Li, Jing

2016-01-01

The streams of Chinese migration to Africa are growing in tandem with rising Chinese investments and trade flows in and to the African continent. In spite of the high profile of this phenomenon in the media, there are few rich and broad descriptions of Chinese communities in Africa. Reasons for this include the rarity of official statistics on foreign-born populations in African censuses, the absence of predefined sampling frames required to draw representative samples with conventional survey methods and difficulties to reach certain segments of this population. Here, we use a novel network-based approach, Network Sampling with Memory, which overcomes the challenges of sampling ‘hidden’ populations in the absence of a sampling frame, to recruit a sample of recent Chinese immigrants in Dar es Salaam, Tanzania and collect information on the demographic characteristics, migration histories and social ties of members of this sample. These data reveal a heterogeneous Chinese community composed of “state-led” migrants who come to Africa to work on projects undertaken by large Chinese state-owned enterprises and “independent” migrants who come on their own accord to engage in various types of business ventures. They offer a rich description of the demographic profile and social organization of this community, highlight key differences between the two categories of migrants and map the structure of the social ties linking them. We highlight needs for future research on inter-group differences in individual motivations for migration, economic activities, migration outcomes, expectations about future residence in Africa, social integration and relations with local communities. PMID:27746912

Electronic media use and addiction among youth in psychiatric clinic versus school populations.

PubMed

Baer, Susan; Saran, Kelly; Green, David A; Hong, Irene

2012-12-01

Electronic media use is highly prevalent among today's youth, and its overuse in the general population has been consistently associated with the presence of psychiatric symptoms. In contrast, little information exists about electronic media use among youth with psychiatric disorders. Our study aims to compare patterns of television and computer and gaming station use among youth in psychiatric clinic and community-based school populations. Surveys were completed by 210 youth and parents, from school (n = 110) and psychiatric clinic (n = 100) populations. Duration and frequency of television, video gaming, and nongaming computer activities were ascertained, along with addictive features of use. Descriptive and comparative analyses were conducted, with a statistical threshold of P < 0.05. Quantitative and qualitative differences were identified between the patterns of use reported by the 2 groups. The mean reported daily duration of exposure to electronic media use was 6.6 hours (SD 4.1) for the clinic sample and 4.6 hours (SD 2.6) for the school sample (P < 0.01). Self-reported rates of addictive patterns related to computer and gaming station use were similar between the 2 populations. However, the clinically based sample favoured more violent games, with 29% reporting playing mature-rated games, compared with 13% reported by the school-based sample (P = 0.02). Youth with externalizing disorders expended greater time video gaming, compared with youth with internalizing disorders (P = 0.01). Clinically based samples of youth with mental illnesses spend more time engaged in electronic media activities and are more likely to play violent video games, compared with youth in the general population. Further research is needed to determine the long-term implications of these differences.

Methodology of the Singapore Indian Chinese Cohort (SICC) eye study: quantifying ethnic variations in the epidemiology of eye diseases in Asians.

PubMed

Lavanya, Raghavan; Jeganathan, V Swetha E; Zheng, Yingfeng; Raju, Prema; Cheung, Ning; Tai, E Shyong; Wang, Jie Jin; Lamoureux, Ecosse; Mitchell, Paul; Young, Terri L; Cajucom-Uy, Howard; Foster, Paul J; Aung, Tin; Saw, Seang Mei; Wong, Tien Y

2009-01-01

Current knowledge of ethnic variability in the epidemiology of major eye diseases in Asia is limited. This report summarizes the rationale and study design of the Singapore Indian Chinese Cohort (SICC) Eye Study, a population-based study of ethnic South Asian (Indians) and East Asian (Chinese) older adults in Singapore. The SICC examined a population-based cross-sectional sample of 3,300 ethnic Indians and 3,300 ethnic Chinese aged 40-80+ years residing in the South-Western part of Singapore. From two lists of 12,000 names of each ethnic group provided by the Ministry of Home Affairs, age-stratified random sampling was used to select 6,350 names in each group, with a target sample size of 3,300. Invitations were sent to attend a central clinic using letters, telephone calls and home visits. Examination procedures included interviews, measurement of blood pressure, anthropometry, presenting and best-corrected visual acuity, subjective refraction, ocular biometry, Goldmann applanation tonometry, slit-lamp biomicroscopy, optic disc imaging and digital photography of the lens and retina, using a standardized protocol. Selected participants underwent gonioscopic examination, visual field testing, and anterior and posterior segment optical coherence tomography. Blood, tear, and urine samples were collected for biochemical analyses, and stored for genetic and proteomic studies. In conjunction with the Singapore Malay Eye Study, the SICC study will permit an in-depth evaluation of the prevalence, risk factors, and impact of major eye diseases in Chinese, Indians and Malays, three distinct Asian ethnic groups, whose combined numbers represent half the world's population.

Selection bias in population-based cancer case-control studies due to incomplete sampling frame coverage.

PubMed

Walsh, Matthew C; Trentham-Dietz, Amy; Gangnon, Ronald E; Nieto, F Javier; Newcomb, Polly A; Palta, Mari

2012-06-01

Increasing numbers of individuals are choosing to opt out of population-based sampling frames due to privacy concerns. This is especially a problem in the selection of controls for case-control studies, as the cases often arise from relatively complete population-based registries, whereas control selection requires a sampling frame. If opt out is also related to risk factors, bias can arise. We linked breast cancer cases who reported having a valid driver's license from the 2004-2008 Wisconsin women's health study (N = 2,988) with a master list of licensed drivers from the Wisconsin Department of Transportation (WDOT). This master list excludes Wisconsin drivers that requested their information not be sold by the state. Multivariate-adjusted selection probability ratios (SPR) were calculated to estimate potential bias when using this driver's license sampling frame to select controls. A total of 962 cases (32%) had opted out of the WDOT sampling frame. Cases age <40 (SPR = 0.90), income either unreported (SPR = 0.89) or greater than $50,000 (SPR = 0.94), lower parity (SPR = 0.96 per one-child decrease), and hormone use (SPR = 0.93) were significantly less likely to be covered by the WDOT sampling frame (α = 0.05 level). Our results indicate the potential for selection bias due to differential opt out between various demographic and behavioral subgroups of controls. As selection bias may differ by exposure and study base, the assessment of potential bias needs to be ongoing. SPRs can be used to predict the direction of bias when cases and controls stem from different sampling frames in population-based case-control studies.

Passive Range of Motion in a Population-Based Sample of Children with Spastic Cerebral Palsy Who Walk

ERIC Educational Resources Information Center

McDowell, Brona C.; Salazar-Torres, Jose J.; Kerr, Claire; Cosgrove, Aidan P.

2012-01-01

-While passive range of motion (PROM) is commonly used to inform decisions on therapeutic management, knowledge of PROM of children with spastic cerebral palsy (CP) is limited. A population-based sample of 178 children with spastic CP (110 male; unilateral, n = 94; bilateral, n = 84; age range 4-17 years) and 68 typically developing children (24…

Measuring the Frequency Occurrence of Handwriting and Handprinting Characteristics^.

PubMed

Johnson, Mark E; Vastrick, Thomas W; Boulanger, Michèle; Schuetzner, Ellen

2017-01-01

The premise of this study was to take a valid population sampling of handwriting and handprinting and assess how many times each of the predetermined characteristic is found in the samples. Approximately 1500 handwriting specimens were collected from across the United States and pared to obtain a representative sample of the U.S. adult population according to selected demographics based on age, sex, ethnicity, handedness, education level, and location of lower-grade school education. This study has been able to support a quantitative assessment of extrinsic and intrinsic effects in handwriting and handprinting for the six subgroups. Additional results include analyses of the interdependence of characteristics. This study found that 98.55% of handprinted characteristics and 97.39% of cursive characteristics had an independence correlation of under 0.2. The conclusions support use of the product rule in general, but with noted caveats. Finally, this study provides frequency occurrence proportions for 776 handwriting and handprinting characteristics. © 2016 American Academy of Forensic Sciences.

Effects of sample size on estimates of population growth rates calculated with matrix models.

PubMed

Fiske, Ian J; Bruna, Emilio M; Bolker, Benjamin M

2008-08-28

Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities.

Population Education in Science: Some Sample Lessons.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Bangkok (Thailand). Regional Office for Education in Asia and Oceania.

This science teacher's manual contains nine sample population education lessons adapted from materials produced in several countries in Asia and Oceania. Activities are designed for lower primary through high school students. Included are class discussions, small group activities, and a role-playing situation. Food chains, human dependence upon…

Two-stage sequential sampling: A neighborhood-free adaptive sampling procedure

USGS Publications Warehouse

Salehi, M.; Smith, D.R.

2005-01-01

Designing an efficient sampling scheme for a rare and clustered population is a challenging area of research. Adaptive cluster sampling, which has been shown to be viable for such a population, is based on sampling a neighborhood of units around a unit that meets a specified condition. However, the edge units produced by sampling neighborhoods have proven to limit the efficiency and applicability of adaptive cluster sampling. We propose a sampling design that is adaptive in the sense that the final sample depends on observed values, but it avoids the use of neighborhoods and the sampling of edge units. Unbiased estimators of population total and its variance are derived using Murthy's estimator. The modified two-stage sampling design is easy to implement and can be applied to a wider range of populations than adaptive cluster sampling. We evaluate the proposed sampling design by simulating sampling of two real biological populations and an artificial population for which the variable of interest took the value either 0 or 1 (e.g., indicating presence and absence of a rare event). We show that the proposed sampling design is more efficient than conventional sampling in nearly all cases. The approach used to derive estimators (Murthy's estimator) opens the door for unbiased estimators to be found for similar sequential sampling designs. ?? 2005 American Statistical Association and the International Biometric Society.

True lemurs…true species - species delimitation using multiple data sources in the brown lemur complex

PubMed Central

2013-01-01

Background Species are the fundamental units in evolutionary biology. However, defining them as evolutionary independent lineages requires integration of several independent sources of information in order to develop robust hypotheses for taxonomic classification. Here, we exemplarily propose an integrative framework for species delimitation in the “brown lemur complex” (BLC) of Madagascar, which consists of seven allopatric populations of the genus Eulemur (Primates: Lemuridae), which were sampled extensively across northern, eastern and western Madagascar to collect fecal samples for DNA extraction as well as recordings of vocalizations. Our data base was extended by including museum specimens with reliable identification and locality information for skull shape and pelage color analysis. Results Between-group analyses of principal components revealed significant heterogeneity in skull shape, pelage color variation and loud calls across all seven populations. Furthermore, post-hoc statistical tests between pairs of populations revealed considerable discordance among different data sets for different dyads. Despite a high degree of incomplete lineage sorting among nuclear loci, significant exclusive ancestry was found for all populations, except for E. cinereiceps, based on one mitochondrial and three nuclear genetic loci. Conclusions Using several independent lines of evidence, our results confirm the species status of the members of the BLC under the general lineage concept of species. More generally, the present analyses demonstrate the importance and value of integrating different kinds of data in delimiting recently evolved radiations. PMID:24159931

Young adults' recreational social environment as a predictor of ecstasy use initiation: findings of a population-based prospective study.

PubMed

Smirnov, Andrew; Najman, Jake M; Hayatbakhsh, Reza; Wells, Helene; Legosz, Margot; Kemp, Robert

2013-10-01

To examine prospectively the contribution of the recreational social environment to ecstasy initiation. Population-based retrospective/prospective cohort study. Data from screening an Australian young adult population to obtain samples of users and non-users of ecstasy. A sample of 204 ecstasy-naive participants aged 19-23 years was obtained, and a 6-month follow-up identified those who initiated ecstasy use. We assessed a range of predictors of ecstasy initiation, including elements of participants' social environment, such as ecstasy-using social contacts and involvement in recreational settings. More than 40% of ecstasy-naive young adults reported ever receiving ecstasy offers. Ecstasy initiation after 6 months was predicted independently by having, at recruitment, many ecstasy-using social contacts [adjusted relative risk (ARR) 3.15, 95% confidence interval (CI): 1.57, 6.34], attending electronic/dance music events (ARR 6.97, 95% CI: 1.99, 24.37), receiving an ecstasy offer (ARR 4.02, 95% CI: 1.23, 13.10), early cannabis use (ARR 4.04, 95% CI: 1.78, 9.17) and psychological distress (ARR 5.34, 95% CI: 2.31, 12.33). Adjusted population-attributable fractions were highest for ecstasy-using social contacts (17.7%) and event attendance (15.1%). In Australia, ecstasy initiation in early adulthood is associated predominantly with social environmental factors, including ecstasy-using social contacts and attendance at dance music events, and is associated less commonly with psychological distress and early cannabis use, respectively. A combination of universal and targeted education programmes may be appropriate for reducing rates of ecstasy initiation and associated harms. © 2013 Society for the Study of Addiction.

A synthesis of convenience survey and other data to estimate undiagnosed HIV infection among men who have sex with men in England and Wales.

PubMed

Walker, Kate; Seaman, Shaun R; De Angelis, Daniela; Presanis, Anne M; Dodds, Julie P; Johnson, Anne M; Mercey, Danielle; Gill, O Noel; Copas, Andrew J

2011-10-01

Hard-to-reach population subgroups are typically investigated using convenience sampling, which may give biased estimates. Combining information from such surveys, a probability survey and clinic surveillance, can potentially minimize the bias. We developed a methodology to estimate the prevalence of undiagnosed HIV infection among men who have sex with men (MSM) in England and Wales aged 16-44 years in 2003, making fuller use of the available data than earlier work. We performed a synthesis of three data sources: genitourinary medicine clinic surveillance (11 380 tests), a venue-based convenience survey including anonymous HIV testing (3702 MSM) and a general population sexual behaviour survey (134 MSM). A logistic regression model to predict undiagnosed infection was fitted to the convenience survey data and then applied to the MSMs in the population survey to estimate the prevalence of undiagnosed infection in the general MSM population. This estimate was corrected for selection biases in the convenience survey using clinic surveillance data. A sensitivity analysis addressed uncertainty in our assumptions. The estimated prevalence of undiagnosed HIV in MSM was 2.4% [95% confidence interval (95% CI 1.7-3.0%)], and between 1.6% (95% CI 1.1-2.0%) and 3.3% (95% CI 2.4-4.1%) depending on assumptions; corresponding to 5500 (3390-7180), 3610 (2180-4740) and 7570 (4790-9840) men, and undiagnosed fractions of 33, 24 and 40%, respectively. Our estimates are consistent with earlier work that did not make full use of data sources. Reconciling data from multiple sources, including probability-, clinic- and venue-based convenience samples can reduce bias in estimates. This methodology could be applied in other settings to take full advantage of multiple imperfect data sources.

Population genetic structure of traditional populations in the Peruvian Central Andes and implications for South American population history.

PubMed

Cabana, Graciela S; Lewis, Cecil M; Tito, Raúl Y; Covey, R Alan; Cáceres, Angela M; Cruz, Augusto F De La; Durand, Diana; Housman, Genevieve; Hulsey, Brannon I; Iannacone, Gian Carlo; López, Paul W; Martínez, Rolando; Medina, Ángel; Dávila, Olimpio Ortega; Pinto, Karla Paloma Osorio; Santillán, Susan I Polo; Domínguez, Percy Rojas; Rubel, Meagan; Smith, Heather F; Smith, Silvia E; Massa, Verónica Rubín de Celis; Lizárraga, Beatriz; Stone, Anne C

2014-01-01

Molecular-based characterizations of Andean peoples are traditionally conducted in the service of elucidating continent-level evolutionary processes in South America. Consequently, genetic variation among "western" Andean populations is often represented in relation to variation among "eastern" Amazon and Orinoco River Basin populations. This west-east contrast in patterns of population genetic variation is typically attributed to large-scale phenomena, such as dual founder colonization events or differing long-term microevolutionary histories. However, alternative explanations that consider the nature and causes of population genetic diversity within the Andean region remain underexplored. Here we examine population genetic diversity in the Peruvian Central Andes using data from the mtDNA first hypervariable region and Y-chromosome short tandem repeats among 17 newly sampled populations and 15 published samples. Using this geographically comprehensive data set, we first reassessed the currently accepted pattern of western versus eastern population genetic structure, which our results ultimately reject: mtDNA population diversities were lower, rather than higher, within Andean versus eastern populations, and only highland Y-chromosomes exhibited significantly higher within-population diversities compared with eastern groups. Multiple populations, including several highland samples, exhibited low genetic diversities for both genetic systems. Second, we explored whether the implementation of Inca state and Spanish colonial policies starting at about ad 1400 could have substantially restructured population genetic variation and consequently constitute a primary explanation for the extant pattern of population diversity in the Peruvian Central Andes. Our results suggest that Peruvian Central Andean population structure cannot be parsimoniously explained as the sole outcome of combined Inca and Spanish policies on the region's population demography: highland populations differed from coastal and lowland populations in mtDNA genetic structure only; highland groups also showed strong evidence of female-biased gene flow and/or effective sizes relative to other Peruvian ecozones. Taken together, these findings indicate that population genetic structure in the Peruvian Central Andes is considerably more complex than previously reported and that characterizations of and explanations for genetic variation may be best pursued within more localized regions and defined time periods.

Share2Quit: Web-Based Peer-Driven Referrals for Smoking Cessation

PubMed Central

2013-01-01

Background Smoking is the number one preventable cause of death in the United States. Effective Web-assisted tobacco interventions are often underutilized and require new and innovative engagement approaches. Web-based peer-driven chain referrals successfully used outside health care have the potential for increasing the reach of Internet interventions. Objective The objective of our study was to describe the protocol for the development and testing of proactive Web-based chain-referral tools for increasing the access to Decide2Quit.org, a Web-assisted tobacco intervention system. Methods We will build and refine proactive chain-referral tools, including email and Facebook referrals. In addition, we will implement respondent-driven sampling (RDS), a controlled chain-referral sampling technique designed to remove inherent biases in chain referrals and obtain a representative sample. We will begin our chain referrals with an initial recruitment of former and current smokers as seeds (initial participants) who will be trained to refer current smokers from their social network using the developed tools. In turn, these newly referred smokers will also be provided the tools to refer other smokers from their social networks. We will model predictors of referral success using sample weights from the RDS to estimate the success of the system in the targeted population. Results This protocol describes the evaluation of proactive Web-based chain-referral tools, which can be used in tobacco interventions to increase the access to hard-to-reach populations, for promoting smoking cessation. Conclusions Share2Quit represents an innovative advancement by capitalizing on naturally occurring technology trends to recruit smokers to Web-assisted tobacco interventions. PMID:24067329

RECRUITING FOR A LONGITUDINAL STUDY OF CHILDREN'S HEALTH USING A HOUSEHOLD-BASED PROBABILITY SAMPLING APPROACH

EPA Science Inventory

The sampling design for the National Children¿s Study (NCS) calls for a population-based, multi-stage, clustered household sampling approach (visit our website for more information on the NCS : www.nationalchildrensstudy.gov). The full sample is designed to be representative of ...

Modelling population distribution using remote sensing imagery and location-based data

NASA Astrophysics Data System (ADS)

Song, J.; Prishchepov, A. V.

2017-12-01

Detailed spatial distribution of population density is essential for city studies such as urban planning, environmental pollution and city emergency, even estimate pressure on the environment and human exposure and risks to health. However, most of the researches used census data as the detailed dynamic population distribution are difficult to acquire, especially in microscale research. This research describes a method using remote sensing imagery and location-based data to model population distribution at the function zone level. Firstly, urban functional zones within a city were mapped by high-resolution remote sensing images and POIs. The workflow of functional zones extraction includes five parts: (1) Urban land use classification. (2) Segmenting images in built-up area. (3) Identification of functional segments by POIs. (4) Identification of functional blocks by functional segmentation and weight coefficients. (5) Assessing accuracy by validation points. The result showed as Fig.1. Secondly, we applied ordinary least square and geographically weighted regression to assess spatial nonstationary relationship between light digital number (DN) and population density of sampling points. The two methods were employed to predict the population distribution over the research area. The R²of GWR model were in the order of 0.7 and typically showed significant variations over the region than traditional OLS model. The result showed as Fig.2.Validation with sampling points of population density demonstrated that the result predicted by the GWR model correlated well with light value. The result showed as Fig.3. Results showed: (1) Population density is not linear correlated with light brightness using global model. (2) VIIRS night-time light data could estimate population density integrating functional zones at city level. (3) GWR is a robust model to map population distribution, the adjusted R2 of corresponding GWR models were higher than the optimal OLS models, confirming that GWR models demonstrate better prediction accuracy. So this method provide detailed population density information for microscale citizen studies.

Mental health differences between German gay and bisexual men and population-based controls.

PubMed

Sattler, Frank A; Franke, Gabriele H; Christiansen, Hanna

2017-07-21

International studies have revealed that gay and bisexual men present more mental health problems than the general male population. Furthermore, there is evidence that minority stress predicts mental health problems in gay and bisexual men. The aim of the present study is to provide initial data on mental health differences in Germany and to analyze the effect of minority stress. Mental health data on n = 1903 German gay and bisexual men and n = 958 men from a population-based sample were assessed using a shortened version of the SCL-90-S. The mental health of the two samples was compared. Furthermore, a linear regression was conducted for the gay and bisexual sample: mental health was used as the criterion and minority stressors as predictors. As compared to our population sample, gay and bisexual men demonstrated more mental health problems with a moderate effect size. In the regression, minority stress predicted mental health problems in the gay and bisexual sample. We observed pronounced mental health differences between gay and bisexual men versus the population sample. These differences could be at least partly due to the minority stress gay and bisexual men face. Research should focus on how to reduce and cope with minority stress.

EvoSNP-DB: A database of genetic diversity in East Asian populations.

PubMed

Kim, Young Uk; Kim, Young Jin; Lee, Jong-Young; Park, Kiejung

2013-08-01

Genome-wide association studies (GWAS) have become popular as an approach for the identification of large numbers of phenotype-associated variants. However, differences in genetic architecture and environmental factors mean that the effect of variants can vary across populations. Understanding population genetic diversity is valuable for the investigation of possible population specific and independent effects of variants. EvoSNP-DB aims to provide information regarding genetic diversity among East Asian populations, including Chinese, Japanese, and Korean. Non-redundant SNPs (1.6 million) were genotyped in 54 Korean trios (162 samples) and were compared with 4 million SNPs from HapMap phase II populations. EvoSNP-DB provides two user interfaces for data query and visualization, and integrates scores of genetic diversity (Fst and VarLD) at the level of SNPs, genes, and chromosome regions. EvoSNP-DB is a web-based application that allows users to navigate and visualize measurements of population genetic differences in an interactive manner, and is available online at [http://biomi.cdc.go.kr/EvoSNP/].

Viewing child pornography: prevalence and correlates in a representative community sample of young Swedish men.

PubMed

Seto, Michael C; Hermann, Chantal A; Kjellgren, Cecilia; Priebe, Gisela; Svedin, Carl Göran; Långström, Niklas

2015-01-01

Most research on child pornography use has been based on selected clinical or criminal justice samples; risk factors for child pornography use in the general population remain largely unexplored. In this study, we examined prevalence, risk factors, and correlates of viewing depictions of adult-child sex in a population-representative sample of 1,978 young Swedish men (17-20 years, Mdn = 18 years, overall response rate, 77 %). In an anonymous, school-based survey, participants self-reported sexual coercion experiences, attitudes and beliefs about sex, perceived peer attitudes, and sexual interests and behaviors; including pornography use, sexual interest in children, and sexually coercive behavior. A total of 84 (4.2 %) young men reported they had ever viewed child pornography. Most theory-based variables were moderately and significantly associated with child pornography viewing and were consistent with models of sexual offending implicating both antisociality and sexual deviance. In multivariate logistic regression analysis, 7 of 15 tested factors independently predicted child pornography viewing and explained 42 % of the variance: ever had sex with a male, likely to have sex with a child aged 12-14, likely to have sex with a child 12 or less, perception of children as seductive, having friends who have watched child pornography, frequent pornography use, and ever viewed violent pornography. From these, a 6-item Child Pornography Correlates Scale was constructed and then cross-validated in a similar but independent Norwegian sample.

Problems with sampling desert tortoises: A simulation analysis based on field data

USGS Publications Warehouse

Freilich, J.E.; Camp, R.J.; Duda, J.J.; Karl, A.E.

2005-01-01

The desert tortoise (Gopherus agassizii) was listed as a U.S. threatened species in 1990 based largely on population declines inferred from mark-recapture surveys of 2.59-km2 (1-mi2) plots. Since then, several census methods have been proposed and tested, but all methods still pose logistical or statistical difficulties. We conducted computer simulations using actual tortoise location data from 2 1-mi2 plot surveys in southern California, USA, to identify strengths and weaknesses of current sampling strategies. We considered tortoise population estimates based on these plots as "truth" and then tested various sampling methods based on sampling smaller plots or transect lines passing through the mile squares. Data were analyzed using Schnabel's mark-recapture estimate and program CAPTURE. Experimental subsampling with replacement of the 1-mi2 data using 1-km2 and 0.25-km2 plot boundaries produced data sets of smaller plot sizes, which we compared to estimates from the 1-mi 2 plots. We also tested distance sampling by saturating a 1-mi 2 site with computer simulated transect lines, once again evaluating bias in density estimates. Subsampling estimates from 1-km2 plots did not differ significantly from the estimates derived at 1-mi2. The 0.25-km2 subsamples significantly overestimated population sizes, chiefly because too few recaptures were made. Distance sampling simulations were biased 80% of the time and had high coefficient of variation to density ratios. Furthermore, a prospective power analysis suggested limited ability to detect population declines as high as 50%. We concluded that poor performance and bias of both sampling procedures was driven by insufficient sample size, suggesting that all efforts must be directed to increasing numbers found in order to produce reliable results. Our results suggest that present methods may not be capable of accurately estimating desert tortoise populations.

Measuring rural women's work and class position.

PubMed

Deere, C D; León de Leal, M

1979-01-01

On the basis of experience gained in researching the economic roles of rural women in a national level study in Colombia and in a regional level study in Peru, some of the methodological problems of measuring rural women's economic participation by sample survey are considered. The specific objective of the sample surveys was to quantify the existing sexual division of labor among the peasant population. The rural household was the unit of analysis, and the focus of measurement was the division of labor by sex in such activities as daily maintenance, household production, and income-generating activitives pursued outside the household. The focus of the survey questionnaire is on the sexual division of labor, but it necessarily must be related to another series of socioeconomic or cultural variables for analysis. The selection of these variables needs to be derived from the hypotheses guiding the study, yet much attention must be given to narrowing the range of inquiry. The time constraint on the length of the questionnaire requires that certain choices be made in terms of the complementary variables to be included. The most important problem in the design of a representative sample survey is the selection of the population to be sampled. The choice of population needs to be compatible with the theoretical framework. Since the interest was to measure the sexual division of labor in terms of class formation, the sample had to be representative of the different class strata in the rural areas. The measurement of access to means of production ideally should be quantitative and qualitative. The choice of the population to be sampled is also constrained by the available data base, a particular problem in rural areas.

Error baseline rates of five sample preparation methods used to characterize RNA virus populations.

PubMed

Kugelman, Jeffrey R; Wiley, Michael R; Nagle, Elyse R; Reyes, Daniel; Pfeffer, Brad P; Kuhn, Jens H; Sanchez-Lockhart, Mariano; Palacios, Gustavo F

2017-01-01

Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic "no amplification" method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a "targeted" amplification method, sequence-independent single-primer amplification (SISPA) as a "random" amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced "no amplification" method, and Illumina TruSeq RNA Access as a "targeted" enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4-5) of all compared methods.

Error baseline rates of five sample preparation methods used to characterize RNA virus populations

PubMed Central

Kugelman, Jeffrey R.; Wiley, Michael R.; Nagle, Elyse R.; Reyes, Daniel; Pfeffer, Brad P.; Kuhn, Jens H.; Sanchez-Lockhart, Mariano; Palacios, Gustavo F.

2017-01-01

Individual RNA viruses typically occur as populations of genomes that differ slightly from each other due to mutations introduced by the error-prone viral polymerase. Understanding the variability of RNA virus genome populations is critical for understanding virus evolution because individual mutant genomes may gain evolutionary selective advantages and give rise to dominant subpopulations, possibly even leading to the emergence of viruses resistant to medical countermeasures. Reverse transcription of virus genome populations followed by next-generation sequencing is the only available method to characterize variation for RNA viruses. However, both steps may lead to the introduction of artificial mutations, thereby skewing the data. To better understand how such errors are introduced during sample preparation, we determined and compared error baseline rates of five different sample preparation methods by analyzing in vitro transcribed Ebola virus RNA from an artificial plasmid-based system. These methods included: shotgun sequencing from plasmid DNA or in vitro transcribed RNA as a basic “no amplification” method, amplicon sequencing from the plasmid DNA or in vitro transcribed RNA as a “targeted” amplification method, sequence-independent single-primer amplification (SISPA) as a “random” amplification method, rolling circle reverse transcription sequencing (CirSeq) as an advanced “no amplification” method, and Illumina TruSeq RNA Access as a “targeted” enrichment method. The measured error frequencies indicate that RNA Access offers the best tradeoff between sensitivity and sample preparation error (1.4−5) of all compared methods. PMID:28182717

Addressing Underrepresentation in Sex Work Research: Reflections on Designing a Purposeful Sampling Strategy.

PubMed

Bungay, Vicky; Oliffe, John; Atchison, Chris

2016-06-01

Men, transgender people, and those working in off-street locales have historically been underrepresented in sex work health research. Failure to include all sections of sex worker populations precludes comprehensive understandings about a range of population health issues, including potential variations in the manifestation of such issues within and between population subgroups, which in turn can impede the development of effective services and interventions. In this article, we describe our attempts to define, determine, and recruit a purposeful sample for a qualitative study examining the interrelationships between sex workers' health and the working conditions in the Vancouver off-street sex industry. Detailed is our application of ethnographic mapping approaches to generate information about population diversity and work settings within distinct geographical boundaries. Bearing in mind the challenges and the overwhelming discrimination sex workers experience, we scope recommendations for safe and effective purposeful sampling inclusive of sex workers' heterogeneity. © The Author(s) 2015.

Challenges of DNA-based mark-recapture studies of American black bears

USGS Publications Warehouse

Settlage, K.E.; Van Manen, F.T.; Clark, J.D.; King, T.L.

2008-01-01

We explored whether genetic sampling would be feasible to provide a region-wide population estimate for American black bears (Ursus americanus) in the southern Appalachians, USA. Specifically, we determined whether adequate capture probabilities (p >0.20) and population estimates with a low coefficient of variation (CV <20%) could be achieved given typical agency budget and personnel constraints. We extracted DNA from hair collected from baited barbed-wire enclosures sampled over a 10-week period on 2 study areas: a high-density black bear population in a portion of Great Smoky Mountains National Park and a lower density population on National Forest lands in North Carolina, South Carolina, and Georgia. We identified individual bears by their unique genotypes obtained from 9 microsatellite loci. We sampled 129 and 60 different bears in the National Park and National Forest study areas, respectively, and applied closed mark–recapture models to estimate population abundance. Capture probabilities and precision of the population estimates were acceptable only for sampling scenarios for which we pooled weekly sampling periods. We detected capture heterogeneity biases, probably because of inadequate spatial coverage by the hair-trapping grid. The logistical challenges of establishing and checking a sufficiently high density of hair traps make DNA-based estimates of black bears impractical for the southern Appalachian region. Alternatives are to estimate population size for smaller areas, estimate population growth rates or survival using mark–recapture methods, or use independent marking and recapturing techniques to reduce capture heterogeneity.

Predicting Health Care Utilization in Marginalized Populations: Black, Female, Street-based Sex Workers

PubMed Central

Varga, Leah M.; Surratt, Hilary L.

2014-01-01

Background Patterns of social and structural factors experienced by vulnerable populations may negatively affect willingness and ability to seek out health care services, and ultimately, their health. Methods The outcome variable was utilization of health care services in the previous 12 months. Using Andersen’s Behavioral Model for Vulnerable Populations, we examined self-reported data on utilization of health care services among a sample of 546 Black, street-based female sex workers in Miami, Florida. To evaluate the impact of each domain of the model on predicting health care utilization, domains were included in the logistic regression analysis by blocks using the traditional variables first and then adding the vulnerable domain variables. Findings The most consistent variables predicting health care utilization were having a regular source of care and self-rated health. The model that included only enabling variables was the most efficient model in predicting health care utilization. Conclusions Any type of resource, link, or connection to or with an institution, or any consistent point of care contributes significantly to health care utilization behaviors. A consistent and reliable source for health care may increase health care utilization and subsequently decrease health disparities among vulnerable and marginalized populations, as well as contribute to public health efforts that encourage preventive health. PMID:24657047

Brief Report: The Prevalence of Neurofibromatosis Type 1 among Children with Autism Spectrum Disorder Identified by the Autism and Developmental Disabilities Monitoring Network

ERIC Educational Resources Information Center

Bilder, Deborah A.; Bakian, Amanda V.; Stevenson, David A.; Carbone, Paul S.; Cunniff, Christopher; Goodman, Alyson B.; McMahon, William M.; Fisher, Nicole P.; Viskochil, David

2016-01-01

Neurofibromatosis type 1 (NF1) is an inherited neurocutaneous disorder associated with neurodevelopmental disorders including autism spectrum disorder (ASD). The frequency of ASD/NF1 co-occurrence has been subject to debate since the 1980s. This relationship was investigated in a large population-based sample of 8-year-old children identified with…

Longitudinal Study of Language and Speech of Twins at 4 and 6 Years: Twinning Effects Decrease, Zygosity Effects Disappear, and Heritability Increases

ERIC Educational Resources Information Center

Rice, Mabel L.; Zubrick, Stephen R.; Taylor, Catherine L.; Hoffman, Lesa; Gayán, Javier

2018-01-01

Purpose: This study investigates the heritability of language, speech, and nonverbal cognitive development of twins at 4 and 6 years of age. Possible confounding effects of twinning and zygosity, evident at 2 years, were investigated among other possible predictors of outcomes. Method: The population-based twin sample included 627 twin pairs and 1…

Genetic Diversity and Population Structure of Leishmania infantum from Southeastern France: Evaluation Using Multi-Locus Microsatellite Typing

PubMed Central

Pomares, Christelle; Marty, Pierre; Bañuls, Anne Laure; Lemichez, Emmanuel; Pratlong, Francine; Faucher, Benoît; Jeddi, Fakhri; Moore, Sandy; Michel, Grégory; Aluru, Srikanth; Piarroux, Renaud; Hide, Mallorie

2016-01-01

In the south of France, Leishmania infantum is responsible for numerous cases of canine leishmaniasis (CanL), sporadic cases of human visceral leishmaniasis (VL) and rare cases of cutaneous and muco-cutaneous leishmaniasis (CL and MCL, respectively). Several endemic areas have been clearly identified in the south of France including the Pyrénées-Orientales, Cévennes (CE), Provence (P), Alpes-Maritimes (AM) and Corsica (CO). Within these endemic areas, the two cities of Nice (AM) and Marseille (P), which are located 150 km apart, and their surroundings, concentrate the greatest number of French autochthonous leishmaniasis cases. In this study, 270 L. infantum isolates from an extended time period (1978–2011) from four endemic areas, AM, P, CE and CO, were assessed using Multi-Locus Microsatellite Typing (MLMT). MLMT revealed a total of 121 different genotypes with 91 unique genotypes and 30 repeated genotypes. Substantial genetic diversity was found with a strong genetic differentiation between the Leishmania populations from AM and P. However, exchanges were observed between these two endemic areas in which it seems that strains spread from AM to P. The genetic differentiations in these areas suggest strong epidemiological structuring. A model-based analysis using STRUCTURE revealed two main populations: population A (consisting of samples primarily from the P and AM endemic areas with MON-1 and non-MON-1 strains) and population B consisting of only MON-1 strains essentially from the AM endemic area. For four patients, we observed several isolates from different biological samples which provided insight into disease relapse and re-infection. These findings shed light on the transmission dynamics of parasites in humans. However, further data are required to confirm this hypothesis based on a limited sample set. This study represents the most extensive population analysis of L. infantum strains using MLMT conducted in France. PMID:26808522

Evidence-based practice guidelines for instructing individuals with neurogenic memory impairments: what have we learned in the past 20 years?

PubMed

Ehlhardt, Laurie A; Sohlberg, McKay Moore; Kennedy, Mary; Coelho, Carl; Ylvisaker, Mark; Turkstra, Lyn; Yorkston, Kathryn

2008-06-01

This article examines the instructional research literature pertinent to teaching procedures or information to individuals with acquired memory impairments due to brain injury or related conditions. The purpose is to evaluate the available evidence in order to generate practice guidelines for clinicians working in the field of cognitive rehabilitation. A systematic review of the instructional literature from 1986 to 2006 revealed 51 studies meeting search criteria. Studies were analysed and coded within the following four key domains: Population Sample, Intervention, Study Design, and Treatment Outcomes. Coding included 17 characteristics of the population sample; seven intervention parameters; five study design features; and five treatment outcome parameters. Interventions that were evaluated included systematic instructional techniques such as method of vanishing cues and errorless learning. The majority of the studies reported positive outcomes in favour of systematic instruction. However, issues related to the design and execution of effective instruction lack clarity and require further study. The interaction between the target learning objective and the individual learner profile is not well understood. The evidence review concludes with clinical recommendations based on the instructional literature and a call to clinicians to incorporate these methods into their practice to maximise patient outcomes.

Toward Robust Estimation of the Components of Forest Population Change

Treesearch

Francis A. Roesch

2014-01-01

Multiple levels of simulation are used to test the robustness of estimators of the components of change. I first created a variety of spatial-temporal populations based on, but more variable than, an actual forest monitoring data set and then sampled those populations under a variety of sampling error structures. The performance of each of four estimation approaches is...

Common needs but divergent interventions for U.S. homeless and foster care children: results from a systematic review.

PubMed

Zlotnick, Cheryl; Tam, Tammy; Zerger, Suzanne

2012-09-01

Many children living in homeless situations in the U.S. have temporary stays in foster care, and both populations suffer disproportionately higher rates of physical, psychological and social difficulties compared with other children. However, very little is known about which specific interventions achieve the best outcomes for children in these overlapping transitional living situations. To address this gap, we review existing literature to identify the most promising practices for children living in transition. A standardised vocabulary specific to each of three electronic databases (i.e. Medline, PsychINFO and CINAHL) was employed to identify studies that described an intervention specifically targeting foster care or homeless children and families. Separate systematic searches were conducted for homeless and foster children, and only studies published in English between January 1993 and February 2009 were selected. The final sample (n = 43) of articles described interventions that fell into two categories: mental health (n = 17) and case management (n = 26). No article included a sample containing both homeless and foster care children, and most studies on homeless children used case management interventions while most studies on foster care children focused on mental health interventions. Few articles employed rigorous study designs. Although repeatedly studies have demonstrated the overlap between populations of homeless and foster care children, studies focused on one population or the other. Virtually all studies on both homeless and foster children devised interventions to reduce trauma and family instability; yet, no evidence-based practice addresses the overlapping needs and potentially relevant evidence-based practice for these two populations. An important and vital next step is to establish an effective evidence-based intervention that reduces the impact of trauma on both U.S. populations of children living in transition. © 2012 Blackwell Publishing Ltd.

Methylenetetrahydrofolate reductase polymorphisms and susceptibility to acute lymphoblastic leukemia in a Chinese population: a meta-analysis.

PubMed

Xiao, Yi; Deng, Tao-Ran; Su, Chang-Liang; Shang, Zhen

2014-01-01

Although many epidemiologic studies have investigated the methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and their association with acute lymphoblastic leukemia (ALL), definitive conclusions cannot be drawn. To clarify the effects of MTHFR polymorphisms on the risk of ALL, a meta-analysis was performed in a Chinese population. A computerized literature search was carried out in PubMed, the Chinese Biomedicine (CBM) database, China National Knowledge Infrastructure (CNKI) platform, and the Wanfang database (Chinese) to collect relevant articles. A total of 11 articles including 1,738 ALL cases and 2,438 controls were included in this meta-analysis. Overall, a significantly decreased association was found between the MTHFR C677T polymorphism and ALL risk when all studies in Chinese populations were pooled into the meta-analysis. In subgroup analyses stratified by age, ethnicity, and source of controls, the same results were observed in children, in population-based studies, and in people with no stated ethnicity. However, a significantly increased association was also found for MTHFR C677T in hospital-based studies, and for MTHFR A1298C in people with no stated ethnicity. Our results suggest that the MTHFR C677T and A1298C polymorphisms may be potential biomarkers for ALL risk in Chinese populations, and studies with a larger sample size and wider population spectrum are required before definitive conclusions can be drawn. © 2014 S. Karger GmbH, Freiburg.

Demographic history and rare allele sharing among human populations.

PubMed

Gravel, Simon; Henn, Brenna M; Gutenkunst, Ryan N; Indap, Amit R; Marth, Gabor T; Clark, Andrew G; Yu, Fuli; Gibbs, Richard A; Bustamante, Carlos D

2011-07-19

High-throughput sequencing technology enables population-level surveys of human genomic variation. Here, we examine the joint allele frequency distributions across continental human populations and present an approach for combining complementary aspects of whole-genome, low-coverage data and targeted high-coverage data. We apply this approach to data generated by the pilot phase of the Thousand Genomes Project, including whole-genome 2-4× coverage data for 179 samples from HapMap European, Asian, and African panels as well as high-coverage target sequencing of the exons of 800 genes from 697 individuals in seven populations. We use the site frequency spectra obtained from these data to infer demographic parameters for an Out-of-Africa model for populations of African, European, and Asian descent and to predict, by a jackknife-based approach, the amount of genetic diversity that will be discovered as sample sizes are increased. We predict that the number of discovered nonsynonymous coding variants will reach 100,000 in each population after ∼1,000 sequenced chromosomes per population, whereas ∼2,500 chromosomes will be needed for the same number of synonymous variants. Beyond this point, the number of segregating sites in the European and Asian panel populations is expected to overcome that of the African panel because of faster recent population growth. Overall, we find that the majority of human genomic variable sites are rare and exhibit little sharing among diverged populations. Our results emphasize that replication of disease association for specific rare genetic variants across diverged populations must overcome both reduced statistical power because of rarity and higher population divergence.

Demographic history and rare allele sharing among human populations

PubMed Central

Gravel, Simon; Henn, Brenna M.; Gutenkunst, Ryan N.; Indap, Amit R.; Marth, Gabor T.; Clark, Andrew G.; Yu, Fuli; Gibbs, Richard A.; Bustamante, Carlos D.; Altshuler, David L.; Durbin, Richard M.; Abecasis, Gonçalo R.; Bentley, David R.; Chakravarti, Aravinda; Clark, Andrew G.; Collins, Francis S.; De La Vega, Francisco M.; Donnelly, Peter; Egholm, Michael; Flicek, Paul; Gabriel, Stacey B.; Gibbs, Richard A.; Knoppers, Bartha M.; Lander, Eric S.; Lehrach, Hans; Mardis, Elaine R.; McVean, Gil A.; Nickerson, Debbie A.; Peltonen, Leena; Schafer, Alan J.; Sherry, Stephen T.; Wang, Jun; Wilson, Richard K.; Gibbs, Richard A.; Deiros, David; Metzker, Mike; Muzny, Donna; Reid, Jeff; Wheeler, David; Wang, Jun; Li, Jingxiang; Jian, Min; Li, Guoqing; Li, Ruiqiang; Liang, Huiqing; Tian, Geng; Wang, Bo; Wang, Jian; Wang, Wei; Yang, Huanming; Zhang, Xiuqing; Zheng, Huisong; Lander, Eric S.; Altshuler, David L.; Ambrogio, Lauren; Bloom, Toby; Cibulskis, Kristian; Fennell, Tim J.; Gabriel, Stacey B.; Jaffe, David B.; Shefler, Erica; Sougnez, Carrie L.; Bentley, David R.; Gormley, Niall; Humphray, Sean; Kingsbury, Zoya; Koko-Gonzales, Paula; Stone, Jennifer; McKernan, Kevin J.; Costa, Gina L.; Ichikawa, Jeffry K.; Lee, Clarence C.; Sudbrak, Ralf; Lehrach, Hans; Borodina, Tatiana A.; Dahl, Andreas; Davydov, Alexey N.; Marquardt, Peter; Mertes, Florian; Nietfeld, Wilfiried; Rosenstiel, Philip; Schreiber, Stefan; Soldatov, Aleksey V.; Timmermann, Bernd; Tolzmann, Marius; Egholm, Michael; Affourtit, Jason; Ashworth, Dana; Attiya, Said; Bachorski, Melissa; Buglione, Eli; Burke, Adam; Caprio, Amanda; Celone, Christopher; Clark, Shauna; Conners, David; Desany, Brian; Gu, Lisa; Guccione, Lorri; Kao, Kalvin; Kebbel, Andrew; Knowlton, Jennifer; Labrecque, Matthew; McDade, Louise; Mealmaker, Craig; Minderman, Melissa; Nawrocki, Anne; Niazi, Faheem; Pareja, Kristen; Ramenani, Ravi; Riches, David; Song, Wanmin; Turcotte, Cynthia; Wang, Shally; Mardis, Elaine R.; Wilson, Richard K.; Dooling, David; Fulton, Lucinda; Fulton, Robert; Weinstock, George; Durbin, Richard M.; Burton, John; Carter, David M.; Churcher, Carol; Coffey, Alison; Cox, Anthony; Palotie, Aarno; Quail, Michael; Skelly, Tom; Stalker, James; Swerdlow, Harold P.; Turner, Daniel; De Witte, Anniek; Giles, Shane; Gibbs, Richard A.; Wheeler, David; Bainbridge, Matthew; Challis, Danny; Sabo, Aniko; Yu, Fuli; Yu, Jin; Wang, Jun; Fang, Xiaodong; Guo, Xiaosen; Li, Ruiqiang; Li, Yingrui; Luo, Ruibang; Tai, Shuaishuai; Wu, Honglong; Zheng, Hancheng; Zheng, Xiaole; Zhou, Yan; Li, Guoqing; Wang, Jian; Yang, Huanming; Marth, Gabor T.; Garrison, Erik P.; Huang, Weichun; Indap, Amit; Kural, Deniz; Lee, Wan-Ping; Leong, Wen Fung; Quinlan, Aaron R.; Stewart, Chip; Stromberg, Michael P.; Ward, Alistair N.; Wu, Jiantao; Lee, Charles; Mills, Ryan E.; Shi, Xinghua; Daly, Mark J.; DePristo, Mark A.; Altshuler, David L.; Ball, Aaron D.; Banks, Eric; Bloom, Toby; Browning, Brian L.; Cibulskis, Kristian; Fennell, Tim J.; Garimella, Kiran V.; Grossman, Sharon R.; Handsaker, Robert E.; Hanna, Matt; Hartl, Chris; Jaffe, David B.; Kernytsky, Andrew M.; Korn, Joshua M.; Li, Heng; Maguire, Jared R.; McCarroll, Steven A.; McKenna, Aaron; Nemesh, James C.; Philippakis, Anthony A.; Poplin, Ryan E.; Price, Alkes; Rivas, Manuel A.; Sabeti, Pardis C.; Schaffner, Stephen F.; Shefler, Erica; Shlyakhter, Ilya A.; Cooper, David N.; Ball, Edward V.; Mort, Matthew; Phillips, Andrew D.; Stenson, Peter D.; Sebat, Jonathan; Makarov, Vladimir; Ye, Kenny; Yoon, Seungtai C.; Bustamante, Carlos D.; Clark, Andrew G.; Boyko, Adam; Degenhardt, Jeremiah; Gravel, Simon; Gutenkunst, Ryan N.; Kaganovich, Mark; Keinan, Alon; Lacroute, Phil; Ma, Xin; Reynolds, Andy; Clarke, Laura; Flicek, Paul; Cunningham, Fiona; Herrero, Javier; Keenen, Stephen; Kulesha, Eugene; Leinonen, Rasko; McLaren, William M.; Radhakrishnan, Rajesh; Smith, Richard E.; Zalunin, Vadim; Zheng-Bradley, Xiangqun; Korbel, Jan O.; Stütz, Adrian M.; Humphray, Sean; Bauer, Markus; Cheetham, R. Keira; Cox, Tony; Eberle, Michael; James, Terena; Kahn, Scott; Murray, Lisa; Chakravarti, Aravinda; Ye, Kai; De La Vega, Francisco M.; Fu, Yutao; Hyland, Fiona C. L.; Manning, Jonathan M.; McLaughlin, Stephen F.; Peckham, Heather E.; Sakarya, Onur; Sun, Yongming A.; Tsung, Eric F.; Batzer, Mark A.; Konkel, Miriam K.; Walker, Jerilyn A.; Sudbrak, Ralf; Albrecht, Marcus W.; Amstislavskiy, Vyacheslav S.; Herwig, Ralf; Parkhomchuk, Dimitri V.; Sherry, Stephen T.; Agarwala, Richa; Khouri, Hoda M.; Morgulis, Aleksandr O.; Paschall, Justin E.; Phan, Lon D.; Rotmistrovsky, Kirill E.; Sanders, Robert D.; Shumway, Martin F.; Xiao, Chunlin; McVean, Gil A.; Auton, Adam; Iqbal, Zamin; Lunter, Gerton; Marchini, Jonathan L.; Moutsianas, Loukas; Myers, Simon; Tumian, Afidalina; Desany, Brian; Knight, James; Winer, Roger; Craig, David W.; Beckstrom-Sternberg, Steve M.; Christoforides, Alexis; Kurdoglu, Ahmet A.; Pearson, John V.; Sinari, Shripad A.; Tembe, Waibhav D.; Haussler, David; Hinrichs, Angie S.; Katzman, Sol J.; Kern, Andrew; Kuhn, Robert M.; Przeworski, Molly; Hernandez, Ryan D.; Howie, Bryan; Kelley, Joanna L.; Melton, S. Cord; Abecasis, Gonçalo R.; Li, Yun; Anderson, Paul; Blackwell, Tom; Chen, Wei; Cookson, William O.; Ding, Jun; Kang, Hyun Min; Lathrop, Mark; Liang, Liming; Moffatt, Miriam F.; Scheet, Paul; Sidore, Carlo; Snyder, Matthew; Zhan, Xiaowei; Zöllner, Sebastian; Awadalla, Philip; Casals, Ferran; Idaghdour, Youssef; Keebler, John; Stone, Eric A.; Zilversmit, Martine; Jorde, Lynn; Xing, Jinchuan; Eichler, Evan E.; Aksay, Gozde; Alkan, Can; Hajirasouliha, Iman; Hormozdiari, Fereydoun; Kidd, Jeffrey M.; Sahinalp, S. Cenk; Sudmant, Peter H.; Mardis, Elaine R.; Chen, Ken; Chinwalla, Asif; Ding, Li; Koboldt, Daniel C.; McLellan, Mike D.; Dooling, David; Weinstock, George; Wallis, John W.; Wendl, Michael C.; Zhang, Qunyuan; Durbin, Richard M.; Albers, Cornelis A.; Ayub, Qasim; Balasubramaniam, Senduran; Barrett, Jeffrey C.; Carter, David M.; Chen, Yuan; Conrad, Donald F.; Danecek, Petr; Dermitzakis, Emmanouil T.; Hu, Min; Huang, Ni; Hurles, Matt E.; Jin, Hanjun; Jostins, Luke; Keane, Thomas M.; Le, Si Quang; Lindsay, Sarah; Long, Quan; MacArthur, Daniel G.; Montgomery, Stephen B.; Parts, Leopold; Stalker, James; Tyler-Smith, Chris; Walter, Klaudia; Zhang, Yujun; Gerstein, Mark B.; Snyder, Michael; Abyzov, Alexej; Balasubramanian, Suganthi; Bjornson, Robert; Du, Jiang; Grubert, Fabian; Habegger, Lukas; Haraksingh, Rajini; Jee, Justin; Khurana, Ekta; Lam, Hugo Y. K.; Leng, Jing; Mu, Xinmeng Jasmine; Urban, Alexander E.; Zhang, Zhengdong; Li, Yingrui; Luo, Ruibang; Marth, Gabor T.; Garrison, Erik P.; Kural, Deniz; Quinlan, Aaron R.; Stewart, Chip; Stromberg, Michael P.; Ward, Alistair N.; Wu, Jiantao; Lee, Charles; Mills, Ryan E.; Shi, Xinghua; McCarroll, Steven A.; Banks, Eric; DePristo, Mark A.; Handsaker, Robert E.; Hartl, Chris; Korn, Joshua M.; Li, Heng; Nemesh, James C.; Sebat, Jonathan; Makarov, Vladimir; Ye, Kenny; Yoon, Seungtai C.; Degenhardt, Jeremiah; Kaganovich, Mark; Clarke, Laura; Smith, Richard E.; Zheng-Bradley, Xiangqun; Korbel, Jan O.; Humphray, Sean; Cheetham, R. Keira; Eberle, Michael; Kahn, Scott; Murray, Lisa; Ye, Kai; De La Vega, Francisco M.; Fu, Yutao; Peckham, Heather E.; Sun, Yongming A.; Batzer, Mark A.; Konkel, Miriam K.; Walker, Jerilyn A.; Xiao, Chunlin; Iqbal, Zamin; Desany, Brian; Blackwell, Tom; Snyder, Matthew; Xing, Jinchuan; Eichler, Evan E.; Aksay, Gozde; Alkan, Can; Hajirasouliha, Iman; Hormozdiari, Fereydoun; Kidd, Jeffrey M.; Chen, Ken; Chinwalla, Asif; Ding, Li; McLellan, Mike D.; Wallis, John W.; Hurles, Matt E.; Conrad, Donald F.; Walter, Klaudia; Zhang, Yujun; Gerstein, Mark B.; Snyder, Michael; Abyzov, Alexej; Du, Jiang; Grubert, Fabian; Haraksingh, Rajini; Jee, Justin; Khurana, Ekta; Lam, Hugo Y. K.; Leng, Jing; Mu, Xinmeng Jasmine; Urban, Alexander E.; Zhang, Zhengdong; Gibbs, Richard A.; Bainbridge, Matthew; Challis, Danny; Coafra, Cristian; Dinh, Huyen; Kovar, Christie; Lee, Sandy; Muzny, Donna; Nazareth, Lynne; Reid, Jeff; Sabo, Aniko; Yu, Fuli; Yu, Jin; Marth, Gabor T.; Garrison, Erik P.; Indap, Amit; Leong, Wen Fung; Quinlan, Aaron R.; Stewart, Chip; Ward, Alistair N.; Wu, Jiantao; Cibulskis, Kristian; Fennell, Tim J.; Gabriel, Stacey B.; Garimella, Kiran V.; Hartl, Chris; Shefler, Erica; Sougnez, Carrie L.; Wilkinson, Jane; Clark, Andrew G.; Gravel, Simon; Grubert, Fabian; Clarke, Laura; Flicek, Paul; Smith, Richard E.; Zheng-Bradley, Xiangqun; Sherry, Stephen T.; Khouri, Hoda M.; Paschall, Justin E.; Shumway, Martin F.; Xiao, Chunlin; McVean, Gil A.; Katzman, Sol J.; Abecasis, Gonçalo R.; Blackwell, Tom; Mardis, Elaine R.; Dooling, David; Fulton, Lucinda; Fulton, Robert; Koboldt, Daniel C.; Durbin, Richard M.; Balasubramaniam, Senduran; Coffey, Allison; Keane, Thomas M.; MacArthur, Daniel G.; Palotie, Aarno; Scott, Carol; Stalker, James; Tyler-Smith, Chris; Gerstein, Mark B.; Balasubramanian, Suganthi; Chakravarti, Aravinda; Knoppers, Bartha M.; Abecasis, Gonçalo R.; Bustamante, Carlos D.; Gharani, Neda; Gibbs, Richard A.; Jorde, Lynn; Kaye, Jane S.; Kent, Alastair; Li, Taosha; McGuire, Amy L.; McVean, Gil A.; Ossorio, Pilar N.; Rotimi, Charles N.; Su, Yeyang; Toji, Lorraine H.; TylerSmith, Chris; Brooks, Lisa D.; Felsenfeld, Adam L.; McEwen, Jean E.; Abdallah, Assya; Juenger, Christopher R.; Clemm, Nicholas C.; Collins, Francis S.; Duncanson, Audrey; Green, Eric D.; Guyer, Mark S.; Peterson, Jane L.; Schafer, Alan J.; Abecasis, Gonçalo R.; Altshuler, David L.; Auton, Adam; Brooks, Lisa D.; Durbin, Richard M.; Gibbs, Richard A.; Hurles, Matt E.; McVean, Gil A.

2011-01-01

High-throughput sequencing technology enables population-level surveys of human genomic variation. Here, we examine the joint allele frequency distributions across continental human populations and present an approach for combining complementary aspects of whole-genome, low-coverage data and targeted high-coverage data. We apply this approach to data generated by the pilot phase of the Thousand Genomes Project, including whole-genome 2–4× coverage data for 179 samples from HapMap European, Asian, and African panels as well as high-coverage target sequencing of the exons of 800 genes from 697 individuals in seven populations. We use the site frequency spectra obtained from these data to infer demographic parameters for an Out-of-Africa model for populations of African, European, and Asian descent and to predict, by a jackknife-based approach, the amount of genetic diversity that will be discovered as sample sizes are increased. We predict that the number of discovered nonsynonymous coding variants will reach 100,000 in each population after ∼1,000 sequenced chromosomes per population, whereas ∼2,500 chromosomes will be needed for the same number of synonymous variants. Beyond this point, the number of segregating sites in the European and Asian panel populations is expected to overcome that of the African panel because of faster recent population growth. Overall, we find that the majority of human genomic variable sites are rare and exhibit little sharing among diverged populations. Our results emphasize that replication of disease association for specific rare genetic variants across diverged populations must overcome both reduced statistical power because of rarity and higher population divergence. PMID:21730125

(I Can't Get No) Saturation: A simulation and guidelines for sample sizes in qualitative research.

PubMed

van Rijnsoever, Frank J

2017-01-01

I explore the sample size in qualitative research that is required to reach theoretical saturation. I conceptualize a population as consisting of sub-populations that contain different types of information sources that hold a number of codes. Theoretical saturation is reached after all the codes in the population have been observed once in the sample. I delineate three different scenarios to sample information sources: "random chance," which is based on probability sampling, "minimal information," which yields at least one new code per sampling step, and "maximum information," which yields the largest number of new codes per sampling step. Next, I use simulations to assess the minimum sample size for each scenario for systematically varying hypothetical populations. I show that theoretical saturation is more dependent on the mean probability of observing codes than on the number of codes in a population. Moreover, the minimal and maximal information scenarios are significantly more efficient than random chance, but yield fewer repetitions per code to validate the findings. I formulate guidelines for purposive sampling and recommend that researchers follow a minimum information scenario.

Methods and background characteristics of the TOHNN study: a population-based study of oral health conditions in northern Norway

PubMed Central

Holde, Gro Eirin; Oscarson, Nils; Tillberg, Anders; Marstrander, Peter; Jönsson, Birgitta

2016-01-01

Objectives The aim of the Tromstannen – Oral Health in Northern Norway (TOHNN) study was to investigate oral health and dental-related diseases in an adult population. This article provides an overview of the background of the study and a description of the sample characteristics and methods employed in data collection. Study design Cross-sectional population-based study including a questionnaire and clinical dental examination. Methods A randomly selected sample of 2,909 individuals (20–79 years old) drawn from the population register was invited to participate in the study. The data were collected between October 2013 and November 2014 in Troms County in northern Norway. The questionnaire focused on oral health-related behaviours and attitudes, oral health-related quality of life, sense of coherence, dental anxiety and symptoms from the temporomandibular joint. The dental examinations, including radiographs, were conducted by 11 dental teams in 5 dental offices. The examination comprised of registration of dental caries, full mouth periodontal status, temporomandibular disorders, mucosal lesions and height and weight. The participants were grouped by age (20–34, 35–49, 50–64 and 65–79) and ethnicity (Norwegian, Sámi, other European and other world). Results From the original sample of 2,909 individuals, 1,986 (68.3%) people participated, of whom 1,019 (51.3%) were women. The highest attendance rate was among women 20–34 years old (80.3%) and the lowest in the oldest age group of women (55.4%). There was no difference in response rate between rural and urban areas. There was a positive correlation between population size and household gross income (p < 0.001) and education level (p < 0.001). The majority of Sámi resided in smaller municipalities. In larger cities, most participants used private dental health care services, whereas, in rural areas, most participants used the public dental health care service. Conclusion The TOHNN study has the potential to generate new knowledge on a wide range of oral health conditions beneficial to the population in Troms County. Due to the high participation rate, generalization both nationally and to the circumpolar area ought to be possible. PMID:26900910

Prevalence of Mycoplasma genitalium in different population groups: systematic review andmeta-analysis.

PubMed

Baumann, Lukas; Cina, Manuel; Egli-Gany, Dianne; Goutaki, Myrofora; Halbeisen, Florian S; Lohrer, Gian-Reto; Ali, Hammad; Scott, Pippa; Low, Nicola

2018-06-01

Mycoplasma genitalium is a common cause of non-gonococcal non-chlamydial urethritis and cervicitis. Testing of asymptomatic populations has been proposed, but prevalence in asymptomatic populations is not well established. We aimed to estimate the prevalence of M. genitalium in the general population, pregnant women, men who have sex with men (MSM), commercial sex workers (CSWs) and clinic-based samples, METHODS: We searched Embase, Medline, IndMED, African Index Medicus and LILACS from 1 January 1991 to 12 July 2016 without language restrictions. We included studies with 500 participants or more. Two reviewers independently screened and selected studies and extracted data. We examined forest plots and conducted random-effects meta-analysis to estimate prevalence, if appropriate. Between-study heterogeneity was examined using the I 2 statistic and meta-regression. Of 3316 screened records, 63 were included. In randomly selected samples from the general population, the summary prevalence was 1.3% (95% CI 1.0% to 1.8%, I 2 41.5%, three studies, 9091 people) in countries with higher levels of development and 3.9% (95% CI 2.2 to 6.7, I 2 89.2%, three studies, 3809 people) in countries with lower levels. Prevalence was similar in women and men (P=0.47). In clinic based samples, prevalence estimates were higher, except in asymptomatic patients (0.8%, 95% CI 0.4 to 1.4, I 2 0.0%, three studies, 2889 people). Summary prevalence estimates were, in the following groups: pregnant women 0.9% (95% CI 0.6% to 1.4%, I 2 0%, four studies, 3472 people), MSM in the community 3.2% (95% CI 2.1 to 5.1, I 2 78.3%, five studies, 3012 people) and female CSWs in the community 15.9% (95% CI 13.5 to 18.9, I 2 79.9%, four studies, 4006 people). This systematic review can inform testing guidelines for M. genitalium . The low estimated prevalence of M. genitalium in the general population, pregnant women and asymptomatic attenders at clinics does not support expansion of testing to these groups. PROSPERO: CRD42015020420. © 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.

Reliable Quantification of the Potential for Equations Based on Spot Urine Samples to Estimate Population Salt Intake: Protocol for a Systematic Review and Meta-Analysis.

PubMed

Huang, Liping; Crino, Michelle; Wu, Jason Hy; Woodward, Mark; Land, Mary-Anne; McLean, Rachael; Webster, Jacqui; Enkhtungalag, Batsaikhan; Nowson, Caryl A; Elliott, Paul; Cogswell, Mary; Toft, Ulla; Mill, Jose G; Furlanetto, Tania W; Ilich, Jasminka Z; Hong, Yet Hoi; Cohall, Damian; Luzardo, Leonella; Noboa, Oscar; Holm, Ellen; Gerbes, Alexander L; Senousy, Bahaa; Pinar Kara, Sonat; Brewster, Lizzy M; Ueshima, Hirotsugu; Subramanian, Srinivas; Teo, Boon Wee; Allen, Norrina; Choudhury, Sohel Reza; Polonia, Jorge; Yasuda, Yoshinari; Campbell, Norm Rc; Neal, Bruce; Petersen, Kristina S

2016-09-21

Methods based on spot urine samples (a single sample at one time-point) have been identified as a possible alternative approach to 24-hour urine samples for determining mean population salt intake. The aim of this study is to identify a reliable method for estimating mean population salt intake from spot urine samples. This will be done by comparing the performance of existing equations against one other and against estimates derived from 24-hour urine samples. The effects of factors such as ethnicity, sex, age, body mass index, antihypertensive drug use, health status, and timing of spot urine collection will be explored. The capacity of spot urine samples to measure change in salt intake over time will also be determined. Finally, we aim to develop a novel equation (or equations) that performs better than existing equations to estimate mean population salt intake. A systematic review and meta-analysis of individual participant data will be conducted. A search has been conducted to identify human studies that report salt (or sodium) excretion based upon 24-hour urine samples and spot urine samples. There were no restrictions on language, study sample size, or characteristics of the study population. MEDLINE via OvidSP (1946-present), Premedline via OvidSP, EMBASE, Global Health via OvidSP (1910-present), and the Cochrane Library were searched, and two reviewers identified eligible studies. The authors of these studies will be invited to contribute data according to a standard format. Individual participant records will be compiled and a series of analyses will be completed to: (1) compare existing equations for estimating 24-hour salt intake from spot urine samples with 24-hour urine samples, and assess the degree of bias according to key demographic and clinical characteristics; (2) assess the reliability of using spot urine samples to measure population changes in salt intake overtime; and (3) develop a novel equation that performs better than existing equations to estimate mean population salt intake. The search strategy identified 538 records; 100 records were obtained for review in full text and 73 have been confirmed as eligible. In addition, 68 abstracts were identified, some of which may contain data eligible for inclusion. Individual participant data will be requested from the authors of eligible studies. Many equations for estimating salt intake from spot urine samples have been developed and validated, although most have been studied in very specific settings. This meta-analysis of individual participant data will enable a much broader understanding of the capacity for spot urine samples to estimate population salt intake.

Assessing the Validity of a Stage Measure on Physical Activity in a Population-Based Sample of Individuals with Type 1 or Type 2 Diabetes

ERIC Educational Resources Information Center

Plotnikoff, Ronald C.; Lippke, Sonia; Reinbold-Matthews, Melissa; Courneya, Kerry S.; Karunamuni, Nandini; Sigal, Ronald J.; Birkett, Nicholas

2007-01-01

This study was designed to test the validity of a transtheoretical model's physical activity (PA) stage measure with intention and different intensities of behavior in a large population-based sample of adults living with diabetes (Type 1 diabetes, n = 697; Type 2 diabetes, n = 1,614) and examine different age groups. The overall…

Evaluation of nitrite contamination in baby foods and infant formulas marketed in Turkey.

PubMed

Erkekoglu, Pinar; Baydar, Terken

2009-05-01

Nitrites are responsible for methemoglobinemia, to which infants younger than 6 months are thought to be the most susceptible population. This study aimed to detect whether there was any nitrite contamination in infant formulas and baby foods marketed in Turkey and to estimate possible toxicological risks in this sensitive physiological period. For this purpose, the samples were randomly collected and divided into four groups: milk-based, cereal-based, vegetable-based, and fruit-based. An easy and reliable spectrophotometric method was used by modifying the Griess method. The average nitrite contamination was found to be 204.07+/-65.80 microg/g in 42 samples, with 1,073 microg/g maximum. According to the results, baby and infant formulas include various nitrite levels; nitrite contamination might come from several sources during manufacturing, and so extreme attention must be given throughout the manufacturing process of food for infants.

Displacement and HIV: Factors Influencing Antiretroviral Therapy Use by Ethnic Shan Migrants in Northern Thailand

PubMed Central

Murray, Jordan K.; DiStefano, Anthony S.; Yang, Joshua S.; Wood, Michele M.

2016-01-01

Migrant populations face increased HIV vulnerabilities, including limited access to antiretroviral therapy (ART). Civil conflict in Myanmar has displaced thousands of people from the minority Shan ethnic group into northern Thailand, where they bear a disproportionate HIV burden. To identify barriers and facilitators of ART use in this population, we conducted a rapid ethnographic assessment and case study with a clinical sample of Shan migrants receiving treatment for HIV in a district hospital in Chiang Mai, Thailand, Thai nurses providing their care, and health care administrators (n = 23). Barriers included fears of arrest and deportation, communication difficulties, perceived social marginalization, limited HIV knowledge, and lack of finances. Facilitating factors included hospital-based migrant registration services and community outreach efforts involving support group mobilization, referral practices, and radio broadcasts. These findings provided a contextualized account to inform policies, community interventions, and nursing practice to increase treatment access for minority migrant groups. PMID:27188762

Psychometric Validation of the Parental Bonding Instrument in a U.K. Population-Based Sample: Role of Gender and Association With Mental Health in Mid-Late Life.

PubMed

Xu, Man K; Morin, Alexandre J S; Marsh, Herbert W; Richards, Marcus; Jones, Peter B

2016-08-01

The factorial structure of the Parental Bonding Instrument (PBI) has been frequently studied in diverse samples but no study has examined its psychometric properties from large, population-based samples. In particular, important questions have not been addressed such as the measurement invariance properties across parental and offspring gender. We evaluated the PBI based on responses from a large, representative population-based sample, using an exploratory structural equation modeling method appropriate for categorical data. Analysis revealed a three-factor structure representing "care," "overprotection," and "autonomy" parenting styles. In terms of psychometric measurement validity, our results supported the complete invariance of the PBI ratings across sons and daughters for their mothers and fathers. The PBI ratings were also robust in relation to personality and mental health status. In terms of predictive value, paternal care showed a protective effect on mental health at age 43 in sons. The PBI is a sound instrument for capturing perceived parenting styles, and is predictive of mental health in middle adulthood. © The Author(s) 2016.

Sampling methods to the statistical control of the production of blood components.

PubMed

Pereira, Paulo; Seghatchian, Jerard; Caldeira, Beatriz; Santos, Paula; Castro, Rosa; Fernandes, Teresa; Xavier, Sandra; de Sousa, Gracinda; de Almeida E Sousa, João Paulo

2017-12-01

The control of blood components specifications is a requirement generalized in Europe by the European Commission Directives and in the US by the AABB standards. The use of a statistical process control methodology is recommended in the related literature, including the EDQM guideline. The control reliability is dependent of the sampling. However, a correct sampling methodology seems not to be systematically applied. Commonly, the sampling is intended to comply uniquely with the 1% specification to the produced blood components. Nevertheless, on a purely statistical viewpoint, this model could be argued not to be related to a consistent sampling technique. This could be a severe limitation to detect abnormal patterns and to assure that the production has a non-significant probability of producing nonconforming components. This article discusses what is happening in blood establishments. Three statistical methodologies are proposed: simple random sampling, sampling based on the proportion of a finite population, and sampling based on the inspection level. The empirical results demonstrate that these models are practicable in blood establishments contributing to the robustness of sampling and related statistical process control decisions for the purpose they are suggested for. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alcohol consumption and cardiorespiratory fitness in five population-based studies.

PubMed

Baumeister, Sebastian E; Finger, Jonas D; Gläser, Sven; Dörr, Marcus; Markus, Marcello Rp; Ewert, Ralf; Felix, Stephan B; Grabe, Hans-Jörgen; Bahls, Martin; Mensink, Gert Bm; Völzke, Henry; Piontek, Katharina; Leitzmann, Michael F

2018-01-01

Background Poor cardiorespiratory fitness is a risk factor for cardiovascular morbidity. Alcohol consumption contributes substantially to the burden of disease, but its association with cardiorespiratory fitness is not well described. We examined associations between average alcohol consumption, heavy episodic drinking and cardiorespiratory fitness. Design The design of this study was as a cross-sectional population-based random sample. Methods We analysed data from five independent population-based studies (Study of Health in Pomerania (2008-2012); German Health Interview and Examination Survey (2008-2011); US National Health and Nutrition Examination Survey (NHANES) 1999-2000; NHANES 2001-2002; NHANES 2003-2004) including 7358 men and women aged 20-85 years, free of lung disease or asthma. Cardiorespiratory fitness, quantified by peak oxygen uptake, was assessed using exercise testing. Information regarding average alcohol consumption (ethanol in grams per day (g/d)) and heavy episodic drinking (5+ or 6+ drinks/occasion) was obtained from self-reports. Fractional polynomial regression models were used to determine the best-fitting dose-response relationship. Results Average alcohol consumption displayed an inverted U-type relation with peak oxygen uptake ( p-value<0.0001), after adjustment for age, sex, education, smoking and physical activity. Compared to individuals consuming 10 g/d (moderate consumption), current abstainers and individuals consuming 50 and 60 g/d had significantly lower peak oxygen uptake values (ml/kg/min) (β coefficients = -1.90, β = -0.06, β = -0.31, respectively). Heavy episodic drinking was not associated with peak oxygen uptake. Conclusions Across multiple adult population-based samples, moderate drinkers displayed better fitness than current abstainers and individuals with higher average alcohol consumption.

Population Genetics of Overwintering Monarch Butterflies, Danaus plexippus (Linnaeus), from Central Mexico Inferred from Mitochondrial DNA and Microsatellite Markers

PubMed Central

Pfeiler, Edward; Nazario-Yepiz, Nestor O.; Pérez-Gálvez, Fernan; Chávez-Mora, Cristina Alejandra; Laclette, Mariana Ramírez Loustalot; Rendón-Salinas, Eduardo

2017-01-01

Abstract Population genetic variation and demographic history in Danaus plexippus (L.), from Mexico were assessed based on analyses of mitochondrial cytochrome c oxidase subunit I (COI; 658 bp) and subunit II (COII; 503 bp) gene segments and 7 microsatellite loci. The sample of 133 individuals included both migratory monarchs, mainly from 4 overwintering sites within the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico (states of Michoacán and México), and a nonmigratory population from Irapuato, Guanajuato. Haplotype (h) and nucleotide (π) diversities were relatively low, averaging 0.466 and 0.00073, respectively, for COI, and 0.629 and 0.00245 for COII. Analysis of molecular variance of the COI data set, which included additional GenBank sequences from a nonmigratory Costa Rican population, showed significant population structure between Mexican migratory monarchs and nonmigratory monarchs from both Mexico and Costa Rica, suggesting limited gene flow between the 2 behaviorally distinct groups. Interestingly, while the COI haplotype frequencies of the nonmigratory populations differed from the migratory, they were similar to each other, despite the great physical distance between them. Microsatellite analyses, however, suggested a lack of structure between the 2 groups, possibly owing to the number of significant deviations from Hardy–Weinberg equilibrium resulting from heterzoygote deficiencies found for most of the loci. Estimates of demographic history of the combined migratory MBBR monarch population, based on the mismatch distribution and Bayesian skyline analyses of the concatenated COI and COII data set (n = 89) suggested a population expansion dating to the late Pleistocene (~35000–40000 years before present) followed by a stable effective female population size (Nef) of about 6 million over the last 10000 years. PMID:28003372

Population Genetics of Overwintering Monarch Butterflies, Danaus plexippus (Linnaeus), from Central Mexico Inferred from Mitochondrial DNA and Microsatellite Markers.

PubMed

Pfeiler, Edward; Nazario-Yepiz, Nestor O; Pérez-Gálvez, Fernan; Chávez-Mora, Cristina Alejandra; Laclette, Mariana Ramírez Loustalot; Rendón-Salinas, Eduardo; Markow, Therese Ann

2017-03-01

Population genetic variation and demographic history in Danaus plexippus (L.), from Mexico were assessed based on analyses of mitochondrial cytochrome c oxidase subunit I (COI; 658 bp) and subunit II (COII; 503 bp) gene segments and 7 microsatellite loci. The sample of 133 individuals included both migratory monarchs, mainly from 4 overwintering sites within the Monarch Butterfly Biosphere Reserve (MBBR) in central Mexico (states of Michoacán and México), and a nonmigratory population from Irapuato, Guanajuato. Haplotype (h) and nucleotide (π) diversities were relatively low, averaging 0.466 and 0.00073, respectively, for COI, and 0.629 and 0.00245 for COII. Analysis of molecular variance of the COI data set, which included additional GenBank sequences from a nonmigratory Costa Rican population, showed significant population structure between Mexican migratory monarchs and nonmigratory monarchs from both Mexico and Costa Rica, suggesting limited gene flow between the 2 behaviorally distinct groups. Interestingly, while the COI haplotype frequencies of the nonmigratory populations differed from the migratory, they were similar to each other, despite the great physical distance between them. Microsatellite analyses, however, suggested a lack of structure between the 2 groups, possibly owing to the number of significant deviations from Hardy-Weinberg equilibrium resulting from heterzoygote deficiencies found for most of the loci. Estimates of demographic history of the combined migratory MBBR monarch population, based on the mismatch distribution and Bayesian skyline analyses of the concatenated COI and COII data set (n = 89) suggested a population expansion dating to the late Pleistocene (~35000-40000 years before present) followed by a stable effective female population size (Nef) of about 6 million over the last 10000 years. © The American Genetic Association 2016.

Confidence intervals for the population mean tailored to small sample sizes, with applications to survey sampling.

PubMed

Rosenblum, Michael A; Laan, Mark J van der

2009-01-07

The validity of standard confidence intervals constructed in survey sampling is based on the central limit theorem. For small sample sizes, the central limit theorem may give a poor approximation, resulting in confidence intervals that are misleading. We discuss this issue and propose methods for constructing confidence intervals for the population mean tailored to small sample sizes. We present a simple approach for constructing confidence intervals for the population mean based on tail bounds for the sample mean that are correct for all sample sizes. Bernstein's inequality provides one such tail bound. The resulting confidence intervals have guaranteed coverage probability under much weaker assumptions than are required for standard methods. A drawback of this approach, as we show, is that these confidence intervals are often quite wide. In response to this, we present a method for constructing much narrower confidence intervals, which are better suited for practical applications, and that are still more robust than confidence intervals based on standard methods, when dealing with small sample sizes. We show how to extend our approaches to much more general estimation problems than estimating the sample mean. We describe how these methods can be used to obtain more reliable confidence intervals in survey sampling. As a concrete example, we construct confidence intervals using our methods for the number of violent deaths between March 2003 and July 2006 in Iraq, based on data from the study "Mortality after the 2003 invasion of Iraq: A cross sectional cluster sample survey," by Burnham et al. (2006).

Periodontitis is related to lung volumes and airflow limitation: a cross-sectional study.

PubMed

Holtfreter, Birte; Richter, Stefanie; Kocher, Thomas; Dörr, Marcus; Völzke, Henry; Ittermann, Till; Obst, Anne; Schäper, Christoph; John, Ulrich; Meisel, Peter; Grotevendt, Anne; Felix, Stephan B; Ewert, Ralf; Gläser, Sven

2013-12-01

This study aimed to assess the potential association of periodontal diseases with lung volumes and airflow limitation in a general adult population. Based on a representative population sample of the Study of Health in Pomerania (SHIP), 1463 subjects aged 25-86 years were included. Periodontal status was assessed by clinical attachment loss (CAL), probing depth and number of missing teeth. Lung function was measured using spirometry, body plethysmography and diffusing capacity of the lung for carbon monoxide. Linear regression models using fractional polynomials were used to assess associations between periodontal disease and lung function. Fibrinogen and high-sensitivity C-reactive protein (hs-CRP) were evaluated as potential intermediate factors. After full adjustment for potential confounders mean CAL was significantly associated with variables of mobile dynamic and static lung volumes, airflow limitation and hyperinflation (p<0.05). Including fibrinogen and hs-CRP did not change coefficients of mean CAL; associations remained statistically significant. Mean CAL was not associated with total lung capacity and diffusing capacity of the lung for carbon monoxide. Associations were confirmed for mean probing depth, extent measures of CAL/probing depth and number of missing teeth. Periodontal disease was significantly associated with reduced lung volumes and airflow limitation in this general adult population sample. Systemic inflammation did not provide a mechanism linking both diseases.

The facilitators and barriers of physical activity among Aboriginal and Torres Strait Islander regional sport participants.

PubMed

Péloquin, Claudie; Doering, Thomas; Alley, Stephanie; Rebar, Amanda

2017-10-01

Disparities in health perspectives between Indigenous and non-Indigenous populations are major concerns in many of the world's well-developed nations. Indigenous populations are largely less healthy, more prone to chronic diseases, and have an earlier overall mortality than non-Indigenous populations. Low levels of physical activity (PA) contribute to the high levels of disease in Indigenous Australians. Qualitative analysis of structured one-on-one interviews discussing PA in a regional setting. Participants were 12 Indigenous Australian adults, and 12 non-Indigenous Australian adults matched on age, sex, and basketball division. Most participants reported engaging in regular exercise; however, the Indigenous group reported more barriers to PA. These factors included cost, time management and environmental constraints. The physical facilitators identified by our Indigenous sample included social support, intrinsic motivation and role modelling. Findings describe individual and external factors that promote or constraint PA as reported by Indigenous Australian adults. Results indicate that Indigenous people face specific barriers to PA when compared to a non-Indigenous sample. Implications for public health: This study is the first to compare the perspective of Indigenous Australians to a matched group of non-Indigenous Australians and provides useful knowledge to develop public health programs based on culturally sensitive data. © 2017 The Authors.

Validation of a Cost-Efficient Multi-Purpose SNP Panel for Disease Based Research

PubMed Central

Hou, Liping; Phillips, Christopher; Azaro, Marco; Brzustowicz, Linda M.; Bartlett, Christopher W.

2011-01-01

Background Here we present convergent methodologies using theoretical calculations, empirical assessment on in-house and publicly available datasets as well as in silico simulations, that validate a panel of SNPs for a variety of necessary tasks in human genetics disease research before resources are committed to larger-scale genotyping studies on those samples. While large-scale well-funded human genetic studies routinely have up to a million SNP genotypes, samples in a human genetics laboratory that are not yet part of such studies may be productively utilized in pilot projects or as part of targeted follow-up work though such smaller scale applications require at least some genome-wide genotype data for quality control purposes such as DNA “barcoding” to detect swaps or contamination issues, determining familial relationships between samples and correcting biases due to population effects such as population stratification in pilot studies. Principal Findings Empirical performance in classification of relative types for any two given DNA samples (e.g., full siblings, parental, etc) indicated that for outbred populations the panel performs sufficiently to classify relationship in extended families and therefore also for smaller structures such as trios and for twin zygosity testing. Additionally, familial relationships do not significantly diminish the (mean match) probability of sharing SNP genotypes in pedigrees, further indicating the uniqueness of the “barcode.” Simulation using these SNPs for an African American case-control disease association study demonstrated that population stratification, even in complex admixed samples, can be adequately corrected under a range of disease models using the SNP panel. Conclusion The panel has been validated for use in a variety of human disease genetics research tasks including sample barcoding, relationship verification, population substructure detection and statistical correction. Given the ease of genotyping our specific assay contained herein, this panel represents a useful and economical panel for human geneticists. PMID:21611176

General Constraints on Sampling Wildlife on FIA Plots

Treesearch

Larissa L. Bailey; John R. Sauer; James D. Nichols; Paul H. Geissler

2005-01-01

This paper reviews the constraints to sampling wildlife populations at FIA points. Wildlife sampling programs must have well-defined goals and provide information adequate to meet those goals. Investigators should choose a State variable based on information needs and the spatial sampling scale. We discuss estimation-based methods for three State variables: species...

Observational studies of patients in the emergency department: a comparison of 4 sampling methods.

PubMed

Valley, Morgan A; Heard, Kennon J; Ginde, Adit A; Lezotte, Dennis C; Lowenstein, Steven R

2012-08-01

We evaluate the ability of 4 sampling methods to generate representative samples of the emergency department (ED) population. We analyzed the electronic records of 21,662 consecutive patient visits at an urban, academic ED. From this population, we simulated different models of study recruitment in the ED by using 2 sample sizes (n=200 and n=400) and 4 sampling methods: true random, random 4-hour time blocks by exact sample size, random 4-hour time blocks by a predetermined number of blocks, and convenience or "business hours." For each method and sample size, we obtained 1,000 samples from the population. Using χ(2) tests, we measured the number of statistically significant differences between the sample and the population for 8 variables (age, sex, race/ethnicity, language, triage acuity, arrival mode, disposition, and payer source). Then, for each variable, method, and sample size, we compared the proportion of the 1,000 samples that differed from the overall ED population to the expected proportion (5%). Only the true random samples represented the population with respect to sex, race/ethnicity, triage acuity, mode of arrival, language, and payer source in at least 95% of the samples. Patient samples obtained using random 4-hour time blocks and business hours sampling systematically differed from the overall ED patient population for several important demographic and clinical variables. However, the magnitude of these differences was not large. Common sampling strategies selected for ED-based studies may affect parameter estimates for several representative population variables. However, the potential for bias for these variables appears small. Copyright © 2012. Published by Mosby, Inc.

Genome sequencing elucidates Sardinian genetic architecture and augments association analyses for lipid and blood inflammatory markers

PubMed Central

Zoledziewska, Magdalena; Mulas, Antonella; Pistis, Giorgio; Steri, Maristella; Danjou, Fabrice; Kwong, Alan; Ortega del Vecchyo, Vicente Diego; Chiang, Charleston W. K.; Bragg-Gresham, Jennifer; Pitzalis, Maristella; Nagaraja, Ramaiah; Tarrier, Brendan; Brennan, Christine; Uzzau, Sergio; Fuchsberger, Christian; Atzeni, Rossano; Reinier, Frederic; Berutti, Riccardo; Huang, Jie; Timpson, Nicholas J; Toniolo, Daniela; Gasparini, Paolo; Malerba, Giovanni; Dedoussis, George; Zeggini, Eleftheria; Soranzo, Nicole; Jones, Chris; Lyons, Robert; Angius, Andrea; Kang, Hyun M.; Novembre, John; Sanna, Serena; Schlessinger, David; Cucca, Francesco; Abecasis, Gonçalo R

2015-01-01

We report ~17.6M genetic variants from whole-genome sequencing of 2,120 Sardinians; 22% are absent from prior sequencing-based compilations and enriched for predicted functional consequence. Furthermore, ~76K variants common in our sample (frequency >5%) are rare elsewhere (<0.5% in the 1000 Genomes Project). We assessed the impact of these variants on circulating lipid levels and five inflammatory biomarkers. Fourteen signals, including two major new loci, were observed for lipid levels, and 19, including two novel loci, for inflammatory markers. New associations would be missed in analyses based on 1000 Genomes data, underlining the advantages of large-scale sequencing in this founder population. PMID:26366554

[Overweight and obesity: prevalence and determining social factors of overweight in the Peruvian population (2009-2010)].

PubMed

Álvarez-Dongo, Doris; Sánchez-Abanto, Jose; Gómez-Guizado, Guillermo; Tarqui-Mamani, Carolina

2012-01-01

Estimate the prevalence of overweight, obesity and the determining social factors of overweight in the Peruvian population. A cross-cut study was conducted which included family members from homes in the sample of the National Household Survey, 2009-2010. Stratified random and multistage sampling was used. The sample included 69 526 members; the anthropometric measurements were done based on the international methodology. To evaluate overweight and obesity, weight-for-height (children <5 years), BMI for age (children and teenagers from 5 to 19 years old), and BMI for adults were used. An analysis of complex samples was made in SPSS and the weighting factor was adjusted. Descriptive statistics and logistic regression were calculated with a 95% confidence interval. Overweight and obesity were higher in young adults (62.3%) and lower in children <5 years old (8.2%). The determining social factors for overweight according to age group were: not being poor (child <5 years old, children 5-9 years old, teenagers and the elderly), living in urban areas (child <5 years old, teenagers, young adults, adults and the elderly) and being a woman (children 5-9 years old, adults and the elderly). Overweight and obesity are indeed a public health issue in Peru. Not being poor and living in urban areas are determining social factors of overweight among Peruvian people.

Feasibility of the music therapy assessment tool for awareness in disorders of consciousness (MATADOC) for use with pediatric populations.

PubMed

Magee, Wendy L; Ghetti, Claire M; Moyer, Alvin

2015-01-01

Measuring responsiveness to gain accurate diagnosis in populations with disorders of consciousness (DOC) is of central concern because these patients have such complex clinical presentations. Due to the uncertainty of accuracy for both behavioral and neurophysiological measures in DOC, combined assessment approaches are recommended. A number of standardized behavioral measures can be used with adults with DOC with minor to moderate reservations relating to the measures' psychometric properties and clinical applicability. However, no measures have been standardized for use with pediatric DOC populations. When adapting adult measures for children, confounding factors include developmental considerations for language-based items included in all DOC measures. Given the lack of pediatric DOC measures, there is a pressing need for measures that are sensitive to the complex clinical presentations typical of DOC and that can accommodate the developmental levels of pediatric populations. The music therapy assessment tool for awareness in disorders of consciousness (MATADOC) is a music-based measure that has been standardized for adults with DOC. Given its emphasis on non-language based sensory stimuli, it is well-suited to pediatric populations spanning developmental stages. In a pre-pilot exploratory study, we examined the clinical utility of this measure and explored trends for test-retest and inter-rater agreement as well as its performance against external reference standards. In several cases, MATADOC items in the visual and auditory domains produced outcomes suggestive of higher level functioning when compared to outcomes provided by other DOC measures. Preliminary findings suggest that the MATADOC provides a useful protocol and measure for behavioral assessment and clinical treatment planning with pediatric DOC. Further research with a larger sample is warranted to test a version of the MATADOC that is refined to meet developmental needs of pediatric DOC populations.

Feasibility of the music therapy assessment tool for awareness in disorders of consciousness (MATADOC) for use with pediatric populations

PubMed Central

Magee, Wendy L.; Ghetti, Claire M.; Moyer, Alvin

2015-01-01

Measuring responsiveness to gain accurate diagnosis in populations with disorders of consciousness (DOC) is of central concern because these patients have such complex clinical presentations. Due to the uncertainty of accuracy for both behavioral and neurophysiological measures in DOC, combined assessment approaches are recommended. A number of standardized behavioral measures can be used with adults with DOC with minor to moderate reservations relating to the measures’ psychometric properties and clinical applicability. However, no measures have been standardized for use with pediatric DOC populations. When adapting adult measures for children, confounding factors include developmental considerations for language-based items included in all DOC measures. Given the lack of pediatric DOC measures, there is a pressing need for measures that are sensitive to the complex clinical presentations typical of DOC and that can accommodate the developmental levels of pediatric populations. The music therapy assessment tool for awareness in disorders of consciousness (MATADOC) is a music-based measure that has been standardized for adults with DOC. Given its emphasis on non-language based sensory stimuli, it is well-suited to pediatric populations spanning developmental stages. In a pre-pilot exploratory study, we examined the clinical utility of this measure and explored trends for test-retest and inter-rater agreement as well as its performance against external reference standards. In several cases, MATADOC items in the visual and auditory domains produced outcomes suggestive of higher level functioning when compared to outcomes provided by other DOC measures. Preliminary findings suggest that the MATADOC provides a useful protocol and measure for behavioral assessment and clinical treatment planning with pediatric DOC. Further research with a larger sample is warranted to test a version of the MATADOC that is refined to meet developmental needs of pediatric DOC populations. PMID:26074850

Confidence intervals for population allele frequencies: the general case of sampling from a finite diploid population of any size.

PubMed

Fung, Tak; Keenan, Kevin

2014-01-01

The estimation of population allele frequencies using sample data forms a central component of studies in population genetics. These estimates can be used to test hypotheses on the evolutionary processes governing changes in genetic variation among populations. However, existing studies frequently do not account for sampling uncertainty in these estimates, thus compromising their utility. Incorporation of this uncertainty has been hindered by the lack of a method for constructing confidence intervals containing the population allele frequencies, for the general case of sampling from a finite diploid population of any size. In this study, we address this important knowledge gap by presenting a rigorous mathematical method to construct such confidence intervals. For a range of scenarios, the method is used to demonstrate that for a particular allele, in order to obtain accurate estimates within 0.05 of the population allele frequency with high probability (> or = 95%), a sample size of > 30 is often required. This analysis is augmented by an application of the method to empirical sample allele frequency data for two populations of the checkerspot butterfly (Melitaea cinxia L.), occupying meadows in Finland. For each population, the method is used to derive > or = 98.3% confidence intervals for the population frequencies of three alleles. These intervals are then used to construct two joint > or = 95% confidence regions, one for the set of three frequencies for each population. These regions are then used to derive a > or = 95%% confidence interval for Jost's D, a measure of genetic differentiation between the two populations. Overall, the results demonstrate the practical utility of the method with respect to informing sampling design and accounting for sampling uncertainty in studies of population genetics, important for scientific hypothesis-testing and also for risk-based natural resource management.

Examining weight and eating behavior by sexual orientation in a sample of male veterans.

PubMed

Bankoff, Sarah M; Richards, Lauren K; Bartlett, Brooke; Wolf, Erika J; Mitchell, Karen S

2016-07-01

Eating disorders are understudied in men and in sexual minority populations; however, extant evidence suggests that gay men have higher rates of disordered eating than heterosexual men. The present study examined the associations between sexual orientation, body mass index (BMI), disordered eating behaviors, and food addiction in a sample of male veterans. Participants included 642 male veterans from the Knowledge Networks-GfK Research Panel. They were randomly selected from a larger study based on previously reported trauma exposure; 96% identified as heterosexual. Measures included the Eating Disorder Diagnostic Scale, the Yale Food Addiction Scale, and self-reported height and weight. Heterosexual and sexual minority men did not differ significantly in terms of BMI. However, gay and bisexual men (n=24) endorsed significantly greater eating disorder symptoms and food addiction compared to heterosexual men. Our findings that sexual minority male veterans may be more likely to experience eating disorder and food addiction symptoms compared to heterosexual male veterans highlight the importance of prevention, assessment, and treatment efforts targeted to this population. Published by Elsevier Inc.

Child mental health differences amongst ethnic groups in Britain: a systematic review

PubMed Central

Goodman, Anna; Patel, Vikram; Leon, David A

2008-01-01

Background Inter-ethnic differences have been reported for many mental health outcomes in the UK, but no systematic review on child mental health has been published. The aim of this review is to compare the population-based prevalence of child mental disorders between ethnic groups in Britain, and relate these findings to ethnic differences in mental health service use. Methods A systematic search of bibliographic databases for population-based and clinic-based studies of children aged 0–19, including all ethnic groups and the main child mental disorders. We synthesised findings by comparing each minority group to the White British study sample. Results 31 population-based and 18 clinic-based studies met the inclusion criteria. Children in the main minority groups have similar or better mental health than White British children for common disorders, but may have higher rates for some less common conditions. The causes of these differences are unclear. There may be unmet need for services among Pakistani and Bangladeshi children. Conclusion Inter-ethnic differences exist but are largely unexplained. Future studies should address the challenges of cross-cultural psychiatry and investigate reasons for inter-ethnic differences. PMID:18655701

SAS procedures for designing and analyzing sample surveys

USGS Publications Warehouse

Stafford, Joshua D.; Reinecke, Kenneth J.; Kaminski, Richard M.

2003-01-01

Complex surveys often are necessary to estimate occurrence (or distribution), density, and abundance of plants and animals for purposes of re-search and conservation. Most scientists are familiar with simple random sampling, where sample units are selected from a population of interest (sampling frame) with equal probability. However, the goal of ecological surveys often is to make inferences about populations over large or complex spatial areas where organisms are not homogeneously distributed or sampling frames are in-convenient or impossible to construct. Candidate sampling strategies for such complex surveys include stratified,multistage, and adaptive sampling (Thompson 1992, Buckland 1994).

Probability Sampling Method for a Hidden Population Using Respondent-Driven Sampling: Simulation for Cancer Survivors.

PubMed

Jung, Minsoo

2015-01-01

When there is no sampling frame within a certain group or the group is concerned that making its population public would bring social stigma, we say the population is hidden. It is difficult to approach this kind of population survey-methodologically because the response rate is low and its members are not quite honest with their responses when probability sampling is used. The only alternative known to address the problems caused by previous methods such as snowball sampling is respondent-driven sampling (RDS), which was developed by Heckathorn and his colleagues. RDS is based on a Markov chain, and uses the social network information of the respondent. This characteristic allows for probability sampling when we survey a hidden population. We verified through computer simulation whether RDS can be used on a hidden population of cancer survivors. According to the simulation results of this thesis, the chain-referral sampling of RDS tends to minimize as the sample gets bigger, and it becomes stabilized as the wave progresses. Therefore, it shows that the final sample information can be completely independent from the initial seeds if a certain level of sample size is secured even if the initial seeds were selected through convenient sampling. Thus, RDS can be considered as an alternative which can improve upon both key informant sampling and ethnographic surveys, and it needs to be utilized for various cases domestically as well.

Harmful practices in the management of childhood diarrhea in low- and middle-income countries: a systematic review.

PubMed

Carter, Emily; Bryce, Jennifer; Perin, Jamie; Newby, Holly

2015-08-18

Harmful practices in the management of childhood diarrhea are associated with negative health outcomes, and conflict with WHO treatment guidelines. These practices include restriction of fluids, breast milk and/or food intake during diarrhea episodes, and incorrect use of modern medicines. We conducted a systematic review of English-language literature published since 1990 to assess the documented prevalence of these four harmful practices, and beliefs, motivations, and contextual factors associated with harmful practices in low- and middle-income countries. We electronically searched PubMed, Embase, Ovid Global Health, and the WHO Global Health Library. Publications reporting the prevalence or substantive findings on beliefs, motivations, or context related to at least one of the four harmful practices were included, regardless of study design or representativeness of the sample population. Of the 114 articles included in the review, 79 reported the prevalence of at least one harmful practice and 35 studies reported on beliefs, motivations, or context for harmful practices. Most studies relied on sub-national population samples and many were limited to small sample sizes. Study design, study population, and definition of harmful practices varied across studies. Reported prevalence of harmful practices varied greatly across study populations, and we were unable to identify clearly defined patterns across regions, countries, or time periods. Caregivers reported that diarrhea management practices were based on the advice of others (health workers, relatives, community members), as well as their own observations or understanding of the efficacy of certain treatments for diarrhea. Others reported following traditionally held beliefs on the causes and cures for specific diarrheal diseases. Available evidence suggests that harmful practices in diarrhea treatment are common in some countries with a high burden of diarrhea-related mortality. These practices can reduce correct management of diarrheal disease in children and result in treatment failure, sustained nutritional deficits, and increased diarrhea mortality. The lack of consistency in sampling, measurement, and reporting identified in this literature review highlights the need to document harmful practices using standard methods of measurement and reporting for the continued reduction of diarrhea mortality.

Prevalence of human papillomavirus infection in women in Portugal: the CLEOPATRE Portugal study.

PubMed

Pista, Angela; de Oliveira, Carlos Freire; Cunha, Maria João; Paixao, Maria Teresa; Real, Odete

2011-08-01

Human papillomavirus (HPV) is responsible for a range of diseases, including cervical cancer. The primary objectives of the CLEOPATRE Portugal study were to estimate the overall and age-stratified prevalence of cervical HPV infection and to assess HPV prevalence and type-specific distribution by cytological results among women aged 18 to 64 years, who reside in mainland Portugal. This cross-sectional population-based study recruited women aged 18 to 64 years, according to an age-stratified sampling strategy, who attended gynecology/obstetrics or sexually transmitted disease clinics across the 5 regional health administrations in mainland Portugal between 2008 and 2009. Liquid-based cytology samples were collected and analyzed centrally for HPV genotyping (clinical array HPV 2 assay) and cytology. Prevalence estimates were adjusted for age using 2007 Portuguese census data. A total of 2326 women were included in the study. The overall prevalence of HPV infection in the study was 19.4% (95% confidence interval, 17.8%-21.0%), with the highest prevalence in women aged 18 to 24 years. High-risk HPV types were detected in 76.5% of infections, of which 36.6% involved multiple types. The commonest high-risk type was HPV-16. At least 1 of the HPV types 6/11/16/18 was detected in 32.6% of infections. The HPV prevalence in normal cytology samples was 16.5%. There was a statistically significant association between high-risk infection and cytological abnormalities (P < 0.001). This is the first population-based study to quantify and describe cervical HPV infection in mainland Portugal. This study provides baseline data for future assessment of the impact of HPV vaccination programs.

Transmission efficiency of the sigma virus in natural populations of its host, Drosophila melanogaster.

PubMed

Fleuriet, A

1982-01-01

A study of the viral samples collected in French natural populations of Drosophila melanogaster since 1969, indicates that natural populations include, as expected, both stabilized and non stabilized infected individuals. In agreement with previous observations made on other characters of the virus, the viral samples collected appear to be homogeneous for the efficiency of the hereditary transmission. However, this efficiency is greater than the average value observed with virus perpetuated in infected laboratory fly strains. One sample collected in Gabon and three in the U.S.A. appear to differ from the French samples for one at least of the traits studied in these experiments.

[Ethical considerations in genomic cohort study].

PubMed

Choi, Eun Kyung; Kim, Ock-Joo

2007-03-01

During the last decade, genomic cohort study has been developed in many countries by linking health data and genetic data in stored samples. Genomic cohort study is expected to find key genetic components that contribute to common diseases, thereby promising great advance in genome medicine. While many countries endeavor to build biobank systems, biobank-based genome research has raised important ethical concerns including genetic privacy, confidentiality, discrimination, and informed consent. Informed consent for biobank poses an important question: whether true informed consent is possible in population-based genomic cohort research where the nature of future studies is unforeseeable when consent is obtained. Due to the sensitive character of genetic information, protecting privacy and keeping confidentiality become important topics. To minimize ethical problems and achieve scientific goals to its maximum degree, each country strives to build population-based genomic cohort research project, by organizing public consultation, trying public and expert consensus in research, and providing safeguards to protect privacy and confidentiality.

Hibernating black holes revealed by photometric mass functions

NASA Astrophysics Data System (ADS)

Casares, Jorge

2018-02-01

We present a novel strategy to uncover the Galactic population of quiescent black holes (BHs). This is based on a new concept, the photometric mass function (PMF), which opens up the possibility of an efficient identification of dynamical BHs in large fields-of-view. This exploits the width of the disc H α emission line, combined with orbital period information. We here show that H α widths can be recovered using a combination of customized H α filters. By setting a width cut-off at 2200 km s-1 we are able to cleanly remove other Galactic populations of H α emitters, including ∼99.9 per cent of cataclysmic variables (CVs). Only short-period (Porb <2.1 h) eclipsing CVs and AGNs will contaminate the sample but these can be easily flagged through photometric variability and, in the latter case, also mid-IR colours. We also describe the strategy of a deep (r = 22) Galactic plane survey based on the concept of PMFs: HAWKs, the HAlpha-Width Kilo-deg Survey. We estimate that ∼800 deg2 are required to unveil ∼50 new dynamical BHs, a three-fold improvement over the known population. For comparison, a century would be needed to produce an enlarged sample of 50 dynamical BHs from X-ray transients at the current discovery rate.

Pattern of relative growth in cockle Anadara antiquata in Ihamahu coastal waters, Central Maluku

NASA Astrophysics Data System (ADS)

Siahainenia, L.; Tuhumury, S. F.; Uneputty, P. A.; Tuhumury, N. C.

2018-03-01

Anadara antiquata is economically important species for fisheries and belong to phylum mollusc which also found in Maluku. However, the density of population begins to decrease recently due to high exploitation by people. The objective of the present study was to analyze relative growth pattern of A. antiquata including size distribution and growth pattern based on shell dimensions. The study was conducted from December 2016 to February 2017 in Ihamahu coastal waters. Data were collected by using purposive random sampling. All the individuals of A. antiquata found were measured the length, width and height by using a vernier caliper to the nearest 0.01mm. Data were analyzed by using SPSS 20 and Microsoft Excel software. The results indicated that the A. antiquata mostly found in seagrass bed with a muddy substrate. The size distribution of shell dimensions was different during sampling. Overall, the length ranged from 15.87 mm to 57.5 mm, the width from 15.50 mm to 48.60 mm and the height was from 9.36 mm to 35.9 mm. The population of A. antiquata consisted of juvenile and mature size. The mature size (> 30 mm) was more dominant in the population. The A. antiquata showed allometric relative growth pattern based on shell dimensions.

Application of multivariate statistics to the Steroidal Module of the Athlete Biological Passport: A proof of concept study.

PubMed

Alladio, Eugenio; Caruso, Roberto; Gerace, Enrico; Amante, Eleonora; Salomone, Alberto; Vincenti, Marco

2016-05-30

The Technical Document TD2014EAAS was drafted by the World Anti-Doping Agency (WADA) in order to fight the spread of endogenous anabolic androgenic steroids (EAAS) misuse in several sport disciplines. In particular, adoption of the so-called Athlete Biological Passport (ABP) - Steroidal Module allowed control laboratories to identify anomalous EAAS concentrations within the athletes' physiological urinary steroidal profile. Gas chromatography (GC) combined with mass spectrometry (MS), indicated by WADA as an appropriate technique to detect urinary EAAS, was utilized in the present study to develop and fully-validate an analytical method for the determination of all EAAS markers specified in TD2014EAAS, plus two further markers hypothetically useful to reveal microbial degradation of the sample. In particular, testosterone, epitestosterone, androsterone, etiocholanolone, 5α-androstane-3α,17β-diol, 5β-androstane-3α,17β-diol, dehydroepiandrosterone, 5α-dihydrotestosterone, were included in the analytical method. Afterwards, the multi-parametric feature of ABP profile was exploited to develop a robust approach for the detection of EAAS misuse, based on multivariate statistical analysis. In particular, Principal Component Analysis (PCA) was combined with Hotelling T(2) tests to explore the EAAS data obtained from 60 sequential urine samples collected from six volunteers, in comparison with a reference population of single urine samples collected from 96 volunteers. The new approach proved capable of identifying anomalous results, including (i) the recognition of samples extraneous to each of the individual urine series and (ii) the discrimination of the urine samples collected from individuals to whom "endogenous" steroids had been administrated with respect to the rest of the samples population. The proof-of-concept results presented in this study will need further extension and validation on a population of sport professionals. Copyright © 2016 Elsevier B.V. All rights reserved.

Evaluating and improving count-based population inference: A case study from 31 years of monitoring Sandhill Cranes

USGS Publications Warehouse

Gerber, Brian D.; Kendall, William L.

2017-01-01

Monitoring animal populations can be difficult. Limited resources often force monitoring programs to rely on unadjusted or smoothed counts as an index of abundance. Smoothing counts is commonly done using a moving-average estimator to dampen sampling variation. These indices are commonly used to inform management decisions, although their reliability is often unknown. We outline a process to evaluate the biological plausibility of annual changes in population counts and indices from a typical monitoring scenario and compare results with a hierarchical Bayesian time series (HBTS) model. We evaluated spring and fall counts, fall indices, and model-based predictions for the Rocky Mountain population (RMP) of Sandhill Cranes (Antigone canadensis) by integrating juvenile recruitment, harvest, and survival into a stochastic stage-based population model. We used simulation to evaluate population indices from the HBTS model and the commonly used 3-yr moving average estimator. We found counts of the RMP to exhibit biologically unrealistic annual change, while the fall population index was largely biologically realistic. HBTS model predictions suggested that the RMP changed little over 31 yr of monitoring, but the pattern depended on assumptions about the observational process. The HBTS model fall population predictions were biologically plausible if observed crane harvest mortality was compensatory up to natural mortality, as empirical evidence suggests. Simulations indicated that the predicted mean of the HBTS model was generally a more reliable estimate of the true population than population indices derived using a moving 3-yr average estimator. Practitioners could gain considerable advantages from modeling population counts using a hierarchical Bayesian autoregressive approach. Advantages would include: (1) obtaining measures of uncertainty; (2) incorporating direct knowledge of the observational and population processes; (3) accommodating missing years of data; and (4) forecasting population size.

Asthma caused by occupational exposures is common – A systematic analysis of estimates of the population-attributable fraction

PubMed Central

Torén, Kjell; Blanc, Paul D

2009-01-01

Background The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures Methods We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review. Results The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%. Conclusion Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents. PMID:19178702

Molecular diversity and population structure of the forage grass Hemarthria compressa (Poaceae) in south China based on SRAP markers.

PubMed

Huang, L-K; Zhang, X-Q; Xie, W-G; Zhang, J; Cheng, L; Yan, H D

2012-08-16

Hemarthria compressa is one of the most important and widely utilized forage crops in south China, owing to its high forage yield and capability of adaptation to hot and humid conditions. We examined the population structure and genetic variation within and among 12 populations of H. compressa in south China using sequence-related amplified polymorphism (SRAP) markers. High genetic diversity was found in these samples [percentage polymorphic bands (PPB) = 82.21%, Shannon's diversity index (I) = 0.352]. However, there was relatively low level of genetic diversity at the population level (PPB = 29.17%, I = 0.155). A high degree of genetic differentiation among populations was detected based on other measures and molecular markers (Nei's genetic diversity analysis: G(ST) = 54.19%; AMOVA analysis: F(ST) = 53.35%). The SRAP markers were found to be more efficient than ISSR markers for evaluating population diversity. Based on these findings, we propose changes in sampling strategies for appraising and utilizing the genetic resources of this species.

Post-traumatic Stress Disorder Is Associated With Irritable Bowel Syndrome in African Americans.

PubMed

Iorio, Natalya; Makipour, Kian; Palit, Amiya; Friedenberg, Frank K

2014-10-30

Psychosocial stressors likely play an important role in irritable bowel syndrome (IBS). The association between IBS and post-trau-matic stress disorder (PTSD) in non-minorities has been described. Our aim was to investigate the potential association between IBS and PTSD in an urban African American population. Our institution maintains a longitudinal population-based survey of African Americans (AA). The survey utilizes a complex, stratified sampling design. The study group consisted of adult AA meeting Rome III criteria for IBS of any subtype. The 4-item Primary Care PTSD screener was administered; score of≥ 3 (range, 0-4) was considered positive for PTSD. Depression (Public Health Questionnaire-9 depression) and anxiety (generalized anxiety disorder-7) levels were measured using standardized scales. To assess quality of life, norm-based physical and mental component summary scores from the short-form 36 health survey ver-sion 2 were obtained. Descriptive and inferential statistics were calculated using Complex Sample Module of SPSS after weight-ing of the study sample. Four hundred nineteen subjects included corresponded to a weighted 21,264 (95% CI, 19,777-22,751) individuals. The preva-lence of IBS in our sample of urban AA was 8.2%. In multivariate regression analysis, female gender, age > 40, higher educa-tional attainment and divorce were independently associated with IBS. Those with IBS were considerably more likely to suffer from PTSD (OR, 4.54; 95% CI, 4.07-5.06). PTSD was independently associated with depression, anxiety, harmful drinking and substance abuse. In AA, PTSD is independently associated with IBS. PTSD has a significantly negative impact on physical and mental self-assess-ment of quality of life. Evaluation of minorities presenting with functional gastrointestinal disorders should include screening for PTSD.(J Neurogastroenterol Motil 2014;20:523-530).

Subgroups of musculoskeletal pain patients and their psychobiological patterns - the LOGIN study protocol.

PubMed

Gerhardt, Andreas; Hartmann, Mechthild; Tesarz, Jonas; Janke, Susanne; Leisner, Sabine; Seidler, Günter; Eich, Wolfgang

2012-08-03

Pain conditions of the musculoskeletal system are very common and have tremendous socioeconomic impact. Despite its high prevalence, musculoskeletal pain remains poorly understood and predominantly non-specifically and insufficiently treated.The group of chronic musculoskeletal pain patients is supposed to be heterogeneous, due to a multitude of mechanisms involved in chronic pain. Psychological variables, psychophysiological processes, and neuroendocrine alterations are expected to be involved. Thus far, studies on musculoskeletal pain have predominantly focused on the general aspects of pain processing, thus neglecting the heterogeneity of patients with musculoskeletal pain. Consequently, there is a need for studies that comprise a multitude of mechanisms that are potentially involved in the chronicity and spread of pain. This need might foster research and facilitate a better pathophysiological understanding of the condition, thereby promoting the development of specific mechanism-based treatments for chronic pain. Therefore, the objectives of this study are as follows: 1) identify and describe subgroups of patients with musculoskeletal pain with regard to clinical manifestations (including mental co-morbidity) and 2) investigate whether distinct sensory profiles or 3) distinct plasma levels of pain-related parameters due to different underlying mechanisms can be distinguished in various subgroups of pain patients. We will examine a population-based chronic pain sample (n = 100), a clinical tertiary care sample (n = 100) and pain-free patients with depression or post-traumatic stress disorder and pain-free healthy controls (each n = 30, respectively). The samples will be pain localisation matched by sex and age to the population-based sample. Patients will undergo physical examination and thorough assessments of mental co-morbidity (including psychological trauma), perceptual and central sensitisation (quantitative sensory testing), descending inhibition (conditioned pain modulation, the diffuse noxious inhibitory control-like effect), as well as measurement of the plasma levels of nerve growth factor and endocannabinoids. The identification of the underlying pathophysiologic mechanisms in different subgroups of chronic musculoskeletal pain patients will contribute to a mechanism-based subgroup classification. This will foster the development of mechanism-based treatments and holds promise to treat patients more sufficient.

Population genomics of C. melanopterus using target gene capture data: demographic inferences and conservation perspectives

PubMed Central

Maisano Delser, Pierpaolo; Corrigan, Shannon; Hale, Matthew; Li, Chenhong; Veuille, Michel; Planes, Serge; Naylor, Gavin; Mona, Stefano

2016-01-01

Population genetics studies on non-model organisms typically involve sampling few markers from multiple individuals. Next-generation sequencing approaches open up the possibility of sampling many more markers from fewer individuals to address the same questions. Here, we applied a target gene capture method to deep sequence ~1000 independent autosomal regions of a non-model organism, the blacktip reef shark (Carcharhinus melanopterus). We devised a sampling scheme based on the predictions of theoretical studies of metapopulations to show that sampling few individuals, but many loci, can be extremely informative to reconstruct the evolutionary history of species. We collected data from a single deme (SID) from Northern Australia and from a scattered sampling representing various locations throughout the Indian Ocean (SCD). We explored the genealogical signature of population dynamics detected from both sampling schemes using an ABC algorithm. We then contrasted these results with those obtained by fitting the data to a non-equilibrium finite island model. Both approaches supported an Nm value ~40, consistent with philopatry in this species. Finally, we demonstrate through simulation that metapopulations exhibit greater resilience to recent changes in effective size compared to unstructured populations. We propose an empirical approach to detect recent bottlenecks based on our sampling scheme. PMID:27651217

Population genomics of C. melanopterus using target gene capture data: demographic inferences and conservation perspectives.

PubMed

Maisano Delser, Pierpaolo; Corrigan, Shannon; Hale, Matthew; Li, Chenhong; Veuille, Michel; Planes, Serge; Naylor, Gavin; Mona, Stefano

2016-09-21

Population genetics studies on non-model organisms typically involve sampling few markers from multiple individuals. Next-generation sequencing approaches open up the possibility of sampling many more markers from fewer individuals to address the same questions. Here, we applied a target gene capture method to deep sequence ~1000 independent autosomal regions of a non-model organism, the blacktip reef shark (Carcharhinus melanopterus). We devised a sampling scheme based on the predictions of theoretical studies of metapopulations to show that sampling few individuals, but many loci, can be extremely informative to reconstruct the evolutionary history of species. We collected data from a single deme (SID) from Northern Australia and from a scattered sampling representing various locations throughout the Indian Ocean (SCD). We explored the genealogical signature of population dynamics detected from both sampling schemes using an ABC algorithm. We then contrasted these results with those obtained by fitting the data to a non-equilibrium finite island model. Both approaches supported an Nm value ~40, consistent with philopatry in this species. Finally, we demonstrate through simulation that metapopulations exhibit greater resilience to recent changes in effective size compared to unstructured populations. We propose an empirical approach to detect recent bottlenecks based on our sampling scheme.

Caste- and ethnicity-based inequalities in HIV/AIDS-related knowledge gap: a case of Nepal.

PubMed

Atteraya, Madhu; Kimm, HeeJin; Song, In Han

2015-05-01

Caste- and ethnicity-based inequalities are major obstacles to achieving health equity. The authors investigated whether there is any association between caste- and ethnicity-based inequalities and HIV-related knowledge within caste and ethnic populations. They used the 2011 Nepal Demographic and Health Survey, a nationally represented cross-sectional study data set. The study sample consisted of 11,273 women between 15 and 49 years of age. Univariate and logistic regression models were used to examine the relationship between caste- and ethnicity-based inequalities and HIV-related knowledge. The study sample was divided into high Hindu caste (47.9 percent), "untouchable" caste (18.4 percent), and indigenous populations (33.7 percent). Within the study sample, the high-caste population was found to have the greatest knowledge of the means by which HIV is prevented and transmitted. After controlling for socioeconomic and demographic characteristics, untouchables were the least knowledgeable. The odds ratio for incomplete knowledge about transmission among indigenous populations was 1.27 times higher than that for high Hindu castes, but there was no significant difference in knowledge of preventive measures. The findings suggest the existence of a prevailing HIV knowledge gap. This in turn suggests that appropriate steps need to be implemented to convey complete knowledge to underprivileged populations.

General Factors of the Korean Exposure Factors Handbook

PubMed Central

Kim, So-Yeon; Kim, Sun-Ja; Lee, Kyung-Eun; Cheong, Hae-Kwan; Kim, Eun-Hye; Choi, Kyung-Ho; Kim, Young-Hee

2014-01-01

Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion. PMID:24570802

Small Bowel Volvulus in the Adult Populace of the United States: Results From a Population-Based Study

PubMed Central

Coe, Taylor M.; Chang, David C.; Sicklick, Jason K.

2015-01-01

Background Small bowel volvulus is a rare entity in Western adults. Greater insight into epidemiology and outcomes may be gained from a national database inquiry. Methods The Nationwide Inpatient Sample (1998–2010), a 20% stratified sample of United States hospitals, was retrospectively reviewed for small bowel volvulus cases (ICD-9 560.2 excluding gastric/colonic procedures) in patients ≥18-years old. Results There were 2,065,599 hospitalizations for bowel obstruction (ICD-9 560.x). Of those, there were 20,680 (1.00%) small bowel volvulus cases; 169 were attributable to intestinal malrotation. Most cases presented emergently (89.24%) and operative management was employed more frequently than non-operative (65.21% vs. 34.79%, P<0.0001). Predictors of mortality included age >50-years, Charlson comorbidity index ≥1, emergent admission, peritonitis, acute vascular insufficiency, coagulopathy, and non-operative management (P<0.0001). Conclusions As the first population-based epidemiological study of small bowel volvulus, our findings provide a robust representation of this rare cause of small bowel obstruction in American adults. PMID:26002189

The Association Between Perceived Discrimination and Obesity in a Population-Based Multiracial and Multiethnic Adult Sample

PubMed Central

Williams, David R.

2009-01-01

Objectives. We examined whether perceived chronic discrimination was related to excess body fat accumulation in a random, multiethnic, population-based sample of US adults. Methods. We used multivariate multinomial logistic regression and logistic regression analyses to examine the relationship between interpersonal experiences of perceived chronic discrimination and body mass index and high-risk waist circumference. Results. Consistent with other studies, our analyses showed that perceived unfair treatment was associated with increased abdominal obesity. Compared with Irish, Jewish, Polish, and Italian Whites who did not experience perceived chronic discrimination, Irish, Jewish, Polish, and Italian Whites who perceived chronic discrimination were 2 to 6 times more likely to have a high-risk waist circumference. No significant relationship between perceived discrimination and the obesity measures was found among the other Whites, Blacks, or Hispanics. Conclusions. These findings are not completely unsupported. White ethnic groups including Polish, Italians, Jews, and Irish have historically been discriminated against in the United States, and other recent research suggests that they experience higher levels of perceived discrimination than do other Whites and that these experiences adversely affect their health. PMID:18923119

Frequency of Dental Caries in Four Historical Populations from the Chalcolithic to the Middle Ages

PubMed Central

Grimoud, A.-M.; Lucas, S.; Sevin, A.; Georges, P.; Passarrius, O.; Duranthon, F.

2011-01-01

The majority of dental carie studies over the course of historical period underline mainly the prevalence evolution, the role of carbohydrates consumption and the impact of access to dietary resources. The purpose of the present investigation was to compare population samples from two archaeological periods the Chacolithic and Middle Age taking into account the geographical and socio economical situation. The study concerned four archaelogical sites in south west France and population samples an inlander for the Chalcolithic Age, an inlander, an costal and urban for the Middle Age. The materials studied included a total of 127 maxillaries, 103 mandibles and 3316 teeth. Data recorded allowed us to display that the Chalcolithic population sample had the lowest carie percentage and the rural inlander population samples of Middle Age the highest; in all cases molars were teeth most often affected. These ones differences could be explained according to time period, carious lesions were usually less recorded in the Chalcolithic Age than the Middle because of a lesser cultivation of cereals like in les Treilles Chacolithic population sample. In the Middle Age population samples, the rural inland sample Marsan showed the highest frequency of caries and ate more cereal than the coastal Vilarnau and the poor urban St Michel population samples, the first one ate fish and Mediterranean vegetal and fruits and the second one met difficulties to food access, in both cases the consumption of carbohydrates was lesser than Marsan population sample who lived in a geographical land convice to cereals cultivation. PMID:22145000

Non-invasive genetic censusing and monitoring of primate populations.

PubMed

Arandjelovic, Mimi; Vigilant, Linda

2018-03-01

Knowing the density or abundance of primate populations is essential for their conservation management and contextualizing socio-demographic and behavioral observations. When direct counts of animals are not possible, genetic analysis of non-invasive samples collected from wildlife populations allows estimates of population size with higher accuracy and precision than is possible using indirect signs. Furthermore, in contrast to traditional indirect survey methods, prolonged or periodic genetic sampling across months or years enables inference of group membership, movement, dynamics, and some kin relationships. Data may also be used to estimate sex ratios, sex differences in dispersal distances, and detect gene flow among locations. Recent advances in capture-recapture models have further improved the precision of population estimates derived from non-invasive samples. Simulations using these methods have shown that the confidence interval of point estimates includes the true population size when assumptions of the models are met, and therefore this range of population size minima and maxima should be emphasized in population monitoring studies. Innovations such as the use of sniffer dogs or anti-poaching patrols for sample collection are important to ensure adequate sampling, and the expected development of efficient and cost-effective genotyping by sequencing methods for DNAs derived from non-invasive samples will automate and speed analyses. © 2018 Wiley Periodicals, Inc.

Reliability and longitudinal change of detrital-zircon age spectra in the Snake River system, Idaho and Wyoming: An example of reproducing the bumpy barcode

NASA Astrophysics Data System (ADS)

Link, Paul Karl; Fanning, C. Mark; Beranek, Luke P.

2005-12-01

Detrital-zircon age-spectra effectively define provenance in Holocene and Neogene fluvial sands from the Snake River system of the northern Rockies, U.S.A. SHRIMP U-Pb dates have been measured for forty-six samples (about 2700 zircon grains) of fluvial and aeolian sediment. The detrital-zircon age distributions are repeatable and demonstrate predictable longitudinal variation. By lumping multiple samples to attain populations of several hundred grains, we recognize distinctive, provenance-defining zircon-age distributions or "barcodes," for fluvial sedimentary systems of several scales, within the upper and middle Snake River system. Our detrital-zircon studies effectively define the geochronology of the northern Rocky Mountains. The composite detrital-zircon grain distribution of the middle Snake River consists of major populations of Neogene, Eocene, and Cretaceous magmatic grains plus intermediate and small grain populations of multiply recycled Grenville (˜950 to 1300 Ma) grains and Yavapai-Mazatzal province grains (˜1600 to 1800 Ma) recycled through the upper Belt Supergroup and Cretaceous sandstones. A wide range of older Paleoproterozoic and Archean grains are also present. The best-case scenario for using detrital-zircon populations to isolate provenance is when there is a point-source pluton with known age, that is only found in one location or drainage. We find three such zircon age-populations in fluvial sediments downstream from the point-source plutons: Ordovician in the southern Beaverhead Mountains, Jurassic in northern Nevada, and Oligocene in the Albion Mountains core complex of southern Idaho. Large detrital-zircon age-populations derived from regionally well-defined, magmatic or recycled sedimentary, sources also serve to delimit the provenance of Neogene fluvial systems. In the Snake River system, defining populations include those derived from Cretaceous Atlanta lobe of the Idaho batholith (80 to 100 Ma), Eocene Challis Volcanic Group and associated plutons (˜45 to 52 Ma), and Neogene rhyolitic Yellowstone-Snake River Plain volcanics (˜0 to 17 Ma). For first-order drainage basins containing these zircon-rich source terranes, or containing a point-source pluton, a 60-grain random sample is sufficient to define the dominant provenance. The most difficult age-distributions to analyze are those that contain multiple small zircon age-populations and no defining large populations. Examples of these include streams draining the Proterozoic and Paleozoic Cordilleran miogeocline in eastern Idaho and Pleistocene loess on the Snake River Plain. For such systems, large sample bases of hundreds of grains, plus the use of statistical methods, may be necessary to distinguish detrital-zircon age-spectra.

How Does Paying Attention Improve Sexual Functioning in Women? A Review of Mechanisms.

PubMed

Arora, Nikita; Brotto, Lori A

2017-07-01

Female sexual dysfunction (FSD), consisting of a constellation of distressing sexual symptoms, is highly prevalent worldwide. Given the central role played by psychological factors in the development of FSD, psychologically and in particular mindfulness-based interventions have arisen as potential treatment options for women. Although mindfulness-based interventions have been evaluated in samples of women with gynecologic cancer; a history of sexual abuse; multiple sclerosis; and spinal cord injury; and provoked vestibulodynia, the mechanisms by which mindfulness leads to improvements in sexual functioning are largely unstudied. To summarize the literature on mechanisms of mindfulness interventions in general and to hypothesize which mechanisms most likely apply to samples of women with FSD. Medline was searched with terms such as mindfulness, meditation, mediator, mode, moderator, mechanism, sex, and sexual dysfunction. Only studies that conducted a formal mediation or moderation analysis were included. We also conducted a broader review on mechanisms in other populations, with slightly modified inclusion criteria: the terms sex and sexual dysfunction were removed and only studies from 2012 to 2016 and studies that included an active mindfulness intervention were included. In general populations, trait mindfulness and decentering were the most common mechanisms identified for the efficacy of mindfulness. In four studies that examined mediators of improvement in samples with FSD, the following mediators were found to be significant: relationship satisfaction, genital self-image, interoceptive awareness, depressed mood, anxiety, and trait mindfulness, of which interoceptive awareness had the most supporting evidence. Clinicians and researchers can use the identified mediators of improvement (ie, interoceptive awareness, depression, and trait mindfulness) when making decisions about which patient might be more likely to benefit from a mindfulness-based approach to treating sexual dysfunction. Future work should examine these mediators and other putative mediators and moderators in randomized controlled trials of mindfulness. Arora N, Brotto LA. How Does Paying Attention Improve Sexual Functioning in Women? A Review of Mechanisms. Sex Med Rev 2017;5:266-274. Copyright © 2017. Published by Elsevier Inc.

The effects of land use on fluvial sediment chemistry for the conterminous U.S. - Results from the first cycle of the NAWQA Program: Trace and major elements, phosphorus, carbon, and sulfur

USGS Publications Warehouse

Horowitz, A.J.; Stephens, V.C.

2008-01-01

In 1991, the U.S. Geological Survey (USGS) began the first cycle of its National Water Quality Assessment (NAWQA) Program. The Program encompassed 51 river basins that collectively accounted for more than 70% of the total water use (excluding power generation), and 50% of the drinking water supply in the U.S. The basins represented a variety of hydrologic settings, rock types (geology), land-use categories, and population densities. One aspect of the first cycle included bed sediment sampling; sites were chosen to represent baseline and important land-use categories (e.g., agriculture, urban) in each basin. In total, over 1200 bed sediment samples were collected. All samples were size-limited (< 63????m) to facilitate spatial and/or temporal comparisons, and subsequently analyzed for a variety of chemical constituents including major (e.g., Fe, Al,) and trace elements (e.g., Cu, Zn, Cd), nutrients (e.g., P), and carbon. The analyses yielded total (??? 95% of the concentrations present), rather than total-recoverable chemical data. Land-use percentages, upstream underlying geology, and population density were determined for each site and evaluated to asses their relative influence on sediment chemistry. Baseline concentrations for the entire U.S. also were generated from a subset of all the samples, and are based on material collected from low population (??? 27??p km- 2) density, low percent urban (??? 5%), agricultural or undeveloped areas. The NAWQA baseline values are similar to those found in other national and global datasets. Further, it appears that upstream/underlying rock type has only a limited effect (mostly major elements) on sediment chemistry. The only land-use category that appears to substantially affect sediment chemistry is percent urban, and this result is mirrored by population density; in fact, the latter appears more consistent than the former.

Creating a sampling frame for population-based veteran research: representativeness and overlap of VA and Department of Defense databases.

PubMed

Washington, Donna L; Sun, Su; Canning, Mark

2010-01-01

Most veteran research is conducted in Department of Veterans Affairs (VA) healthcare settings, although most veterans obtain healthcare outside the VA. Our objective was to determine the adequacy and relative contributions of Veterans Health Administration (VHA), Veterans Benefits Administration (VBA), and Department of Defense (DOD) administrative databases for representing the U.S. veteran population, using as an example the creation of a sampling frame for the National Survey of Women Veterans. In 2008, we merged the VHA, VBA, and DOD databases. We identified the number of unique records both overall and from each database. The combined databases yielded 925,946 unique records, representing 51% of the 1,802,000 U.S. women veteran population. The DOD database included 30% of the population (with 8% overlap with other databases). The VHA enrollment database contributed an additional 20% unique women veterans (with 6% overlap with VBA databases). VBA databases contributed an additional 2% unique women veterans (beyond 10% overlap with other databases). Use of VBA and DOD databases substantially expands access to the population of veterans beyond those in VHA databases, regardless of VA use. Adoption of these additional databases would enhance the value and generalizability of a wide range of studies of both male and female veterans.

An Evaluation of Population Density Mapping and Built up Area Estimates in Sri Lanka Using Multiple Methodologies

NASA Astrophysics Data System (ADS)

Engstrom, R.; Soundararajan, V.; Newhouse, D.

2017-12-01

In this study we examine how well multiple population density and built up estimates that utilize satellite data compare in Sri Lanka. The population relationship is examined at the Gram Niladhari (GN) level, the lowest administrative unit in Sri Lanka from the 2011 census. For this study we have two spatial domains, the whole country and a 3,500km2 sub-sample, for which we have complete high spatial resolution imagery coverage. For both the entire country and the sub-sample we examine how consistent are the existing publicly available measures of population constructed from satellite imagery at predicting population density? For just the sub-sample we examine how well do a suite of values derived from high spatial resolution satellite imagery predict population density and how does our built up area estimate compare to other publicly available estimates. Population measures were obtained from the Sri Lankan census, and were downloaded from Facebook, WorldPoP, GPW, and Landscan. Percentage built-up area at the GN level was calculated from three sources: Facebook, Global Urban Footprint (GUF), and the Global Human Settlement Layer (GHSL). For the sub-sample we have derived a variety of indicators from the high spatial resolution imagery. Using deep learning convolutional neural networks, an object oriented, and a non-overlapping block, spatial feature approach. Variables calculated include: cars, shadows (a proxy for building height), built up area, and buildings, roof types, roads, type of agriculture, NDVI, Pantex, and Histogram of Oriented Gradients (HOG) and others. Results indicate that population estimates are accurate at the higher, DS Division level but not necessarily at the GN level. Estimates from Facebook correlated well with census population (GN correlation of 0.91) but measures from GPW and WorldPop are more weakly correlated (0.64 and 0.34). Estimates of built-up area appear to be reliable. In the 32 DSD-subsample, Facebook's built- up area measure is highly correlated with our built-up measure (correlation of 0.9). Preliminary regression results based on variables selected from Lasso-regressions indicate that satellite indicators have exceptionally strong predictive power in predicting GN level population level and density with an out of sample r-squared of 0.75 and 0.72 respectively.

The Drosophila genome nexus: a population genomic resource of 623 Drosophila melanogaster genomes, including 197 from a single ancestral range population.

PubMed

Lack, Justin B; Cardeno, Charis M; Crepeau, Marc W; Taylor, William; Corbett-Detig, Russell B; Stevens, Kristian A; Langley, Charles H; Pool, John E

2015-04-01

Hundreds of wild-derived Drosophila melanogaster genomes have been published, but rigorous comparisons across data sets are precluded by differences in alignment methodology. The most common approach to reference-based genome assembly is a single round of alignment followed by quality filtering and variant detection. We evaluated variations and extensions of this approach and settled on an assembly strategy that utilizes two alignment programs and incorporates both substitutions and short indels to construct an updated reference for a second round of mapping prior to final variant detection. Utilizing this approach, we reassembled published D. melanogaster population genomic data sets and added unpublished genomes from several sub-Saharan populations. Most notably, we present aligned data from phase 3 of the Drosophila Population Genomics Project (DPGP3), which provides 197 genomes from a single ancestral range population of D. melanogaster (from Zambia). The large sample size, high genetic diversity, and potentially simpler demographic history of the DPGP3 sample will make this a highly valuable resource for fundamental population genetic research. The complete set of assemblies described here, termed the Drosophila Genome Nexus, presently comprises 623 consistently aligned genomes and is publicly available in multiple formats with supporting documentation and bioinformatic tools. This resource will greatly facilitate population genomic analysis in this model species by reducing the methodological differences between data sets. Copyright © 2015 by the Genetics Society of America.

Population genetic structure of the blue-fronted Amazon (Amazona aestiva, Psittacidae: Aves) based on nuclear microsatellite loci: implications for conservation.

PubMed

Leite, K C E; Seixas, G H F; Berkunsky, I; Collevatti, R G; Caparroz, R

2008-09-09

The blue-fronted Amazon (Amazona aestiva) is a widely distributed Neotropical parrot and one of the most captured parrots in nature to supply the illegal trade of wild animals. The objectives of the present study were to analyze the genetic structure of A. aestiva to identify management units and support conservation planning and to verified if A. aestiva populations have undergone a recent bottleneck due to habitat loss and capture for the pet trade. The genetic structure was accessed by analyzing six microsatellite loci in 74 individuals of A. aestiva, including samples from the two subspecies (A. a. aestiva and A. a. xanthopteryx), from five populations: four in Brazil and one in Argentina. A significant genetic differentiation (theta = 0.007, p = 0.005) could be detected only between the most distant populations, Tocantins and Argentina, localized at the northeast and southwest limits of the sample sites, respectively. There was no evidence of inbreeding within or between populations, suggesting random mating among individuals. These results suggest a clinal distribution of genetic variability, as observed for variation in plumage color of the two A. aestiva subspecies. Bottleneck analysis did not show a recent reduction in population size. Thus, for the management and conservation of the species, the populations from Argentina and Tocantins should be considered as different management units, and the other populations from the center of the geographical distribution as another management unit.

Does beekeeping reduce genetic variability in Melipona scutellaris (Apidae, Meliponini)?

PubMed

Carvalho-Zilse, G A; Costa-Pinto, M F F; Nunes-Silva, C G; Kerr, W E

2009-06-30

Many factors have contributed to reductions in wild populations of stingless bees, such as: deforestation, displacement and destruction of nests by honey gatherers, as well as use of insecticides and other agrochemicals. All of these can potentially affect the populational structure of native species. We analyzed genetic variability and populational structure of Melipona scutellaris, based on five microsatellite loci, using heterologous primers of M. bicolor. Samples were taken from 43 meliponaries distributed among 30 sites of four northeastern states of Brazil (Pernambuco, Alagoas, Sergipe, and Bahia). Thirty-one alleles were found to be well distributed among the populations, with sizes ranging from 85 to 146 bp. In general, there was a variable distribution and frequency of alleles among populations, with either exclusive and/or fixed alleles at some sites. The population of Pernambuco was the most polymorphic, followed by Bahia, Alagoas and Sergipe. The heterozygosity was Ho = 0.36 on average, much lower than what has been reported for M. bicolor (Ho = 0.65). Most populations were not under Hardy-Weinberg equilibrium. We found a higher variation within rather than among populations, indicating no genetic structuring in those bees maintained in meliponaries. This apparent homogenization may be due to intense beekeeping activity, including exchange of genetic material among beekeepers. Based on our findings, we recommend more studies of meliponaries and of wild populations in order to help orient management and conservation of these native pollinators.

Incidence of utilization- and symptom-defined COPD exacerbations in hospital- and population-recruited patients.

PubMed

Erdal, Marta; Johannessen, Ane; Eagan, Tomas Mikal; Bakke, Per; Gulsvik, Amund; Grønseth, Rune

2016-01-01

The objectives of this study were to estimate the impact of recruitment source and outcome definition on the incidence of acute exacerbations of COPD (AECOPD) and explore possible predictors of AECOPD. During a 1-year follow-up, we performed a baseline visit and four telephone interviews of 81 COPD patients and 132 controls recruited from a population-based survey and 205 hospital-recruited COPD patients. Both a definition based on health care utilization and a symptom-based definition of AECOPD were applied. For multivariate analyses, we chose a negative binomial regression model. COPD patients from the population- and hospital-based samples experienced on average 0.4 utilization-defined and 2.9 symptom-defined versus 1.0 and 5.9 annual exacerbations, respectively. The incidence rate ratios for utilization-defined AECOPD were 2.45 (95% CI 1.22-4.95), 3.43 (95% CI 1.59-7.38), and 5.67 (95% CI 2.58-12.48) with Global Initiative on Obstructive Lung Disease spirometric stages II, III, and IV, respectively. The corresponding incidence rate ratios for the symptom-based definition were 3.08 (95% CI 1.96-4.84), 3.45 (95% CI 1.92-6.18), and 4.00 (95% CI 2.09-7.66). Maintenance therapy (regular long-acting muscarinic antagonists, long-acting beta-2 agonists, inhaled corticosteroids, or theophylline) also increased the risk of AECOPD with both exacerbation definitions (incidence rate ratios 1.65 and 1.73, respectively). The risk of AECOPD was 59%-78% higher in the hospital sample than in the population sample. If externally valid conclusions are to be made regarding incidence and predictors of AECOPD, studies should be based on general population samples or adjustments should be made on account of a likely higher incidence in other samples. Likewise, the effect of different AECOPD definitions should be taken into consideration.

Potential Information Loss Due to Categorization of Minimum Inhibitory Concentration Frequency Distributions.

PubMed

Mazloom, Reza; Jaberi-Douraki, Majid; Comer, Jeffrey R; Volkova, Victoriya

2018-01-01

A bacterial isolate's susceptibility to antimicrobial is expressed as the lowest drug concentration inhibiting its visible growth, termed minimum inhibitory concentration (MIC). The susceptibilities of isolates from a host population at a particular time vary, with isolates with specific MICs present at different frequencies. Currently, for either clinical or monitoring purposes, an isolate is most often categorized as Susceptible, Intermediate, or Resistant to the antimicrobial by comparing its MIC to a breakpoint value. Such data categorizations are known in statistics to cause information loss compared to analyzing the underlying frequency distributions. The U.S. National Antimicrobial Resistance Monitoring System (NARMS) includes foodborne bacteria at the food animal processing and retail product points. The breakpoints used to interpret the MIC values for foodborne bacteria are those relevant to clinical treatments by the antimicrobials in humans in whom the isolates were to cause infection. However, conceptually different objectives arise when inference is sought concerning changes in susceptibility/resistance across isolates of a bacterial species in host populations among different sampling points or times. For the NARMS 1996-2013 data for animal processing and retail, we determined the fraction of comparisons of susceptibility/resistance to 44 antimicrobial drugs of twelve classes of a bacterial species in a given animal host or product population where there was a significant change in the MIC frequency distributions between consecutive years or the two sampling points, while the categorization-based analyses concluded no change. The categorization-based analyses missed significant changes in 54% of the year-to-year comparisons and in 71% of the slaughter-to-retail within-year comparisons. Hence, analyses using the breakpoint-based categorizations of the MIC data may miss significant developments in the resistance distributions between the sampling points or times. Methods considering the MIC frequency distributions in their entirety may be superior for epidemiological analyses of resistance dynamics in populations.

IDENTIFYING A POPULATION-BASED SAMPLE OF WOMEN OF REPRODUCTIVE AGE FOR ENVIRONMENTAL STUDIES USING A COMMERCIAL TELEPHONE DIRECTORY

EPA Science Inventory

Environmental studies examining reproductive endpoints such as spontaneous abortion or fertility often rely on very select study groups (i.e., convenience samples, highly exposed, etc.) that cannot be easily generalized to the overall population. For exposures limited to a parti...

Awareness of cervical cancer risk factors and symptoms: cross-sectional community survey in post-conflict northern Uganda.

PubMed

Mwaka, Amos D; Orach, Christopher G; Were, Edward M; Lyratzopoulos, Georgios; Wabinga, Henry; Roland, Martin

2016-08-01

Lack of awareness of risk factors and symptoms for cancer may lead to late diagnosis and poor prognosis. We assessed community awareness about cervical cancer risk factors and symptoms and perceptions about prevention and cure of cervical cancer in order to contribute data to inform interventions to improve cervical cancer survival. Cross-sectional population-based survey. We conducted this study in Gulu, a post-conflict district in Uganda in 2012. The sample included 448 persons aged 18 years and above, selected through a multi-stage stratified cluster sampling process. We collected data using a pretested structured questionnaire. Logistic regressions were used to determine magnitudes of associations between socio-demographic and outcome variables. Most participants (444/448) had heard about cervical cancer. Known risk factors including multiple sexual partners, human papillomavirus infection, and early onset of sexual activity, were recognized by 88%, 82%, and 78% of respondents respectively. 63% of participants believed that prolonged use of family planning pills and injections caused cervical cancer. The majority of participants recognized symptoms of cervical cancer including inter-menstrual bleeding (85%), post-menopausal bleeding (84%), and offensive vaginal discharge (83%). 70% of participants believed that cervical cancer is preventable and 92% believed that it could be cured if diagnosed at an early stage. Recognition of cervical cancer risk factors and symptoms was high among study participants. Targeted interventions including increasing availability of HPV vaccination, population-based cervical screening and diagnostic services can translate high awareness into actual benefits. © 2015 The Authors. Health Expectations Published by John Wiley & Sons Ltd.

The Use of Genetics for the Management of a Recovering Population: Temporal Assessment of Migratory Peregrine Falcons in North America

PubMed Central

Johnson, Jeff A.; Talbot, Sandra L.; Sage, George K.; Burnham, Kurt K.; Brown, Joseph W.; Maechtle, Tom L.; Seegar, William S.; Yates, Michael A.; Anderson, Bud; Mindell, David P.

2010-01-01

Background Our ability to monitor populations or species that were once threatened or endangered and in the process of recovery is enhanced by using genetic methods to assess overall population stability and size over time. This can be accomplished most directly by obtaining genetic measures from temporally-spaced samples that reflect the overall stability of the population as given by changes in genetic diversity levels (allelic richness and heterozygosity), degree of population differentiation (F ST and D EST), and effective population size (N e). The primary goal of any recovery effort is to produce a long-term self-sustaining population, and these genetic measures provide a metric by which we can gauge our progress and help make important management decisions. Methodology/Principal Findings The peregrine falcon in North America (Falco peregrinus tundrius and anatum) was delisted in 1994 and 1999, respectively, and its abundance will be monitored by the species Recovery Team every three years until 2015. Although the United States Fish and Wildlife Service makes a distinction between tundrius and anatum subspecies, our genetic results based on eleven microsatellite loci suggest limited differentiation that can be attributed to an isolation by distance relationship and warrant no delineation of these two subspecies in its northern latitudinal distribution from Alaska through Canada into Greenland. Using temporal samples collected at Padre Island, Texas during migration (seven temporal time periods between 1985–2007), no significant differences in genetic diversity or significant population differentiation in allele frequencies between time periods were observed and were indistinguishable from those obtained from tundrius/anatum breeding locations throughout their northern distribution. Estimates of harmonic mean N e were variable and imprecise, but always greater than 500 when employing multiple temporal genetic methods. Conclusions/Significance These results, including those from simulations to assess the power of each method to estimate N e, suggest a stable or growing population, which is consistent with ongoing field-based monitoring surveys. Therefore, historic and continuing efforts to prevent the extinction of the peregrine falcon in North America appear successful with no indication of recent decline, at least from the northern latitude range-wide perspective. The results also further highlight the importance of archiving samples and their use for continual assessment of population recovery and long-term viability. PMID:21124969

The international growth standard for preadolescent and adolescent children: statistical considerations.

PubMed

Cole, T J

2006-12-01

This article discusses statistical considerations for the design of a new study intended to provide an International Growth Standard for Preadolescent and Adolescent Children, including issues such as cross-sectional, longitudinal, and mixed designs; sample-size derivation for the number of populations and number of children per population; modeling of growth centiles of height, weight, and other measurements; and modeling of the adolescent growth spurt. The conclusions are that a mixed longitudinal design will provide information on both growth distance and velocity; samples of children from 5 to 10 sites should be suitable for an international standard (based on political rather than statistical arguments); the samples should be broadly uniform across age but oversampled during puberty, and should include data into adulthood. The LMS method is recommended for constructing measurement centiles, and parametric or semiparametric approaches are available to estimate the timing of the adolescent growth spurt in individuals. If the new standard is to be grafted onto the 2006 World Health Organization (WHO) reference, caution is needed at the join point of 5 years, where children from the new standard are likely to be appreciably more obese than those from the WHO reference, due to the rising trends in obesity and the time gap in data collection between the two surveys.

Are great apes able to reason from multi-item samples to populations of food items?

PubMed

Eckert, Johanna; Rakoczy, Hannes; Call, Josep

2017-10-01

Inductive learning from limited observations is a cognitive capacity of fundamental importance. In humans, it is underwritten by our intuitive statistics, the ability to draw systematic inferences from populations to randomly drawn samples and vice versa. According to recent research in cognitive development, human intuitive statistics develops early in infancy. Recent work in comparative psychology has produced first evidence for analogous cognitive capacities in great apes who flexibly drew inferences from populations to samples. In the present study, we investigated whether great apes (Pongo abelii, Pan troglodytes, Pan paniscus, Gorilla gorilla) also draw inductive inferences in the opposite direction, from samples to populations. In two experiments, apes saw an experimenter randomly drawing one multi-item sample from each of two populations of food items. The populations differed in their proportion of preferred to neutral items (24:6 vs. 6:24) but apes saw only the distribution of food items in the samples that reflected the distribution of the respective populations (e.g., 4:1 vs. 1:4). Based on this observation they were then allowed to choose between the two populations. Results show that apes seemed to make inferences from samples to populations and thus chose the population from which the more favorable (4:1) sample was drawn in Experiment 1. In this experiment, the more attractive sample not only contained proportionally but also absolutely more preferred food items than the less attractive sample. Experiment 2, however, revealed that when absolute and relative frequencies were disentangled, apes performed at chance level. Whether these limitations in apes' performance reflect true limits of cognitive competence or merely performance limitations due to accessory task demands is still an open question. © 2017 Wiley Periodicals, Inc.

Cortical morphology as a shared neurobiological substrate of attention-deficit/hyperactivity symptoms and executive functioning: a population-based pediatric neuroimaging study

PubMed Central

Mous, Sabine E.; White, Tonya; Muetzel, Ryan L.; El Marroun, Hanan; Rijlaarsdam, Jolien; Polderman, Tinca J.C.; Jaddoe, Vincent W.; Verhulst, Frank C.; Posthuma, Danielle; Tiemeier, Henning

2017-01-01

Background Attention-deficit/hyperactivity symptoms have repeatedly been associated with poor cognitive functioning. Genetic studies have demonstrated a shared etiology of attention-deficit/hyperactivity disorder (ADHD) and cognitive ability, suggesting a common underlying neurobiology of ADHD and cognition. Further, neuroimaging studies suggest that altered cortical development is related to ADHD. In a large population-based sample we investigated whether cortical morphology, as a potential neurobiological substrate, underlies the association between attention-deficit/hyperactivity symptoms and cognitive problems. Methods The sample consisted of school-aged children with data on attention-deficit/hyperactivity symptoms, cognitive functioning and structural imaging. First, we investigated the association between attention-deficit/hyperactivity symptoms and different domains of cognition. Next, we identified cortical correlates of attention-deficit/hyperactivity symptoms and related cognitive domains. Finally, we studied the role of cortical thickness and gyrification in the behaviour–cognition associations. Results We included 776 children in our analyses. We found that attention-deficit/hyperactivity symptoms were associated specifically with problems in attention and executive functioning (EF; b = −0.041, 95% confidence interval [CI] −0.07 to −0.01, p = 0.004). Cortical thickness and gyrification were associated with both attention-deficit/hyperactivity symptoms and EF in brain regions that have been previously implicated in ADHD. This partly explained the association between attention-deficit/hyperactivity symptoms and EF (bindirect = −0.008, bias-corrected 95% CI −0.018 to −0.001). Limitations The nature of our study did not allow us to draw inferences regarding temporal associations; longitudinal studies are needed for clarification. Conclusion In a large, population-based sample of children, we identified a shared cortical morphology underlying attention-deficit/hyperactivity symptoms and EF. PMID:27673503

Self-esteem and Mortality: Prospective Evidence from a Population-based Study

PubMed Central

STAMATAKIS, KATHERINE A.; LYNCH, JOHN; EVERSON, SUSAN A.; RAGHUNATHAN, TRIVELLORE; SALONEN, JUKKA T.; KAPLAN, GEORGE A.

2011-01-01

OBJECTIVE Self-esteem is considered to be importantly associated with both psychosocial states such as depression as well as physical health. There are no population-based studies that examine the association between self-esteem and mortality. The objective of this study was to assess whether low self-esteem was prospectively associated with increased risk of death in a population-based sample of Finnish men. METHODS A sample of 2682 male residents of Kuopio, Finland were interviewed and followed prospectively as part of the Kuopio Ischemic Heart Disease Risk Factor Study (KIHD). Characteristics of the KIHD sample at baseline included self-esteem, measured by the Rosenberg ten-item scale, socioeconomic factors, behavioral risk factors, other psychosocial characteristics, and prevalent diseases. Mortality was ascertained through linkage to the Finnish national death registry. We assessed the relationship between self-esteem and all-cause mortality using Cox proportional hazards models. RESULTS Low self-esteem was associated with a two-fold [hazard ratio (HR) = 2.0, 95% confidence interval (CI) = 1.3–3.2] increase in age-adjusted mortality. This relationship was partially explained by behavioral and socioeconomic factors, and prevalent diseases, and fully explained by other psychosocial characteristics (hopelessness, depression, cynical hostility, and sullenness). When adjusted for hopelessness alone there was no increased risk associated with low self-esteem (HR = 1.3, 95% CI = 0.8–2.2). CONCLUSIONS This study found no association between self-esteem and all-cause mortality after adjustment for other psychosocial characteristics, primarily hopelessness. Our understanding of the observed relationships between some psychosocial factors and mortality may be improved by simultaneous measurement of multiple psychosocial domains, thus diminishing the potential for residual confounding. PMID:14664781

Cortical morphology as a shared neurobiological substrate of attention-deficit/hyperactivity symptoms and executive functioning: a population-based pediatric neuroimaging study.

PubMed

Mous, Sabine E; White, Tonya; Muetzel, Ryan L; El Marroun, Hanan; Rijlaarsdam, Jolien; Polderman, Tinca J C; Jaddoe, Vincent W; Verhulst, Frank C; Posthuma, Danielle; Tiemeier, Henning

2017-03-01

Attention-deficit/hyperactivity symptoms have repeatedly been associated with poor cognitive functioning. Genetic studies have demonstrated a shared etiology of attention-deficit/hyperactivity disorder (ADHD) and cognitive ability, suggesting a common underlying neurobiology of ADHD and cognition. Further, neuroimaging studies suggest that altered cortical development is related to ADHD. In a large population-based sample we investigated whether cortical morphology, as a potential neurobiological substrate, underlies the association between attention-deficit/hyperactivity symptoms and cognitive problems. The sample consisted of school-aged children with data on attention-deficit/hyperactivity symptoms, cognitive functioning and structural imaging. First, we investigated the association between attention-deficit/ hyperactivity symptoms and different domains of cognition. Next, we identified cortical correlates of attention-deficit/hyperactivity symptoms and related cognitive domains. Finally, we studied the role of cortical thickness and gyrification in the behaviour-cognition associations. We included 776 children in our analyses. We found that attention-deficit/hyperactivity symptoms were associated specifically with problems in attention and executive functioning (EF; b = -0.041, 95% confidence interval [CI] -0.07 to -0.01, p = 0.004). Cortical thickness and gyrification were associated with both attention-deficit/hyperactivity symptoms and EF in brain regions that have been previously implicated in ADHD. This partly explained the association between attention-deficit/hyperactivity symptoms and EF (b indirect = -0.008, bias-corrected 95% CI -0.018 to -0.001). The nature of our study did not allow us to draw inferences regarding temporal associations; longitudinal studies are needed for clarification. In a large, population-based sample of children, we identified a shared cortical morphology underlying attention-deficit/hyperactivity symptoms and EF.

Population-based multicase-control study in common tumors in Spain (MCC-Spain): rationale and study design.

PubMed

Castaño-Vinyals, Gemma; Aragonés, Nuria; Pérez-Gómez, Beatriz; Martín, Vicente; Llorca, Javier; Moreno, Victor; Altzibar, Jone M; Ardanaz, Eva; de Sanjosé, Sílvia; Jiménez-Moleón, José Juan; Tardón, Adonina; Alguacil, Juan; Peiró, Rosana; Marcos-Gragera, Rafael; Navarro, Carmen; Pollán, Marina; Kogevinas, Manolis

2015-01-01

We present the protocol of a large population-based case-control study of 5 common tumors in Spain (MCC-Spain) that evaluates environmental exposures and genetic factors. Between 2008-2013, 10,183 persons aged 20-85 years were enrolled in 23 hospitals and primary care centres in 12 Spanish provinces including 1,115 cases of a new diagnosis of prostate cancer, 1,750 of breast cancer, 2,171 of colorectal cancer, 492 of gastro-oesophageal cancer, 554 cases of chronic lymphocytic leukaemia (CLL) and 4,101 population-based controls matched by frequency to cases by age, sex and region of residence. Participation rates ranged from 57% (stomach cancer) to 87% (CLL cases) and from 30% to 77% in controls. Participants completed a face-to-face computerized interview on sociodemographic factors, environmental exposures, occupation, medication, lifestyle, and personal and family medical history. In addition, participants completed a self-administered food-frequency questionnaire and telephone interviews. Blood samples were collected from 76% of participants while saliva samples were collected in CLL cases and participants refusing blood extractions. Clinical information was recorded for cases and paraffin blocks and/or fresh tumor samples are available in most collaborating hospitals. Genotyping was done through an exome array enriched with genetic markers in specific pathways. Multiple analyses are planned to assess the association of environmental, personal and genetic risk factors for each tumor and to identify pleiotropic effects. This study, conducted within the Spanish Consortium for Biomedical Research in Epidemiology & Public Health (CIBERESP), is a unique initiative to evaluate etiological factors for common cancers and will promote cancer research and prevention in Spain. Copyright © 2014 SESPAS. Published by Elsevier Espana. All rights reserved.

Y-chromosomal diversity of the Valachs from the Czech Republic: model for isolated population in Central Europe

PubMed Central

Ehler, Edvard; Vaněk, Daniel; Stenzl, Vlastimil; Vančata, Václav

2011-01-01

Aim To evaluate Y-chromosomal diversity of the Moravian Valachs of the Czech Republic and compare them with a Czech population sample and other samples from Central and South-Eastern Europe, and to evaluate the effects of genetic isolation and sampling. Methods The first sample set of the Valachs consisted of 94 unrelated male donors from the Valach region in northeastern Czech Republic border-area. The second sample set of the Valachs consisted of 79 men who originated from 7 paternal lineages defined by surname. No close relatives were sampled. The third sample set consisted of 273 unrelated men from the whole of the Czech Republic and was used for comparison, as well as published data for other 27 populations. The total number of samples was 3244. Y-short tandem repeat (STR) markers were typed by standard methods using PowerPlex® Y System (Promega) and Yfiler® Amplification Kit (Applied Biosystems) kits. Y-chromosomal haplogroups were estimated from the haplotype information. Haplotype diversity and other intra- and inter-population statistics were computed. Results The Moravian Valachs showed a lower genetic variability of Y-STR markers than other Central European populations, resembling more to the isolated Balkan populations (Aromuns, Csango, Bulgarian, and Macedonian Roma) than the surrounding populations (Czechs, Slovaks, Poles, Saxons). We illustrated the effect of sampling on Valach paternal lineages, which includes reduction of discrimination capacity and variability inside Y-chromosomal haplogroups. Valach modal haplotype belongs to R1a haplogroup and it was not detected in the Czech population. Conclusion The Moravian Valachs display strong substructure and isolation in their Y chromosomal markers. They represent a unique Central European population model for population genetics. PMID:21674832

Perceived stigmatization and discrimination of people with mental illness: A survey-based study of the general population in five metropolitan cities in India.

PubMed

Böge, Kerem; Zieger, Aron; Mungee, Aditya; Tandon, Abhinav; Fuchs, Lukas Marian; Schomerus, Georg; Tam Ta, Thi Minh; Dettling, Michael; Bajbouj, Malek; Angermeyer, Matthias; Hahn, Eric

2018-01-01

India faces a significant gap between the prevalence of mental illness among the population and the availability and effectiveness of mental health care in providing adequate treatment. This discrepancy results in structural stigma toward mental illness which in turn is one of the main reasons for a persistence of the treatment gap, whereas societal factors such as religion, education, and family structures play critical roles. This survey-based study investigates perceived stigma toward mental illness in five metropolitan cities in India and explores the roles of relevant sociodemographic factors. Samples were collected in five metropolitan cities in India including Chennai ( n = 166), Kolkata ( n = 158), Hyderabad ( n = 139), Lucknow ( n = 183), and Mumbai ( n = 278). Stratified quota sampling was used to match the general population concerning age, gender, and religion. Further, sociodemographic variables such as educational attainment and strength of religious beliefs were included in the statistical analysis. Participants displayed overall high levels of perceived stigma. Multiple linear regression analysis found a significant effect of gender ( P < 0.01), with female participants showing higher levels of perceived stigma compared to male counterparts. Gender differences in cultural and societal roles and expectations could account for higher levels of perceived stigma among female participants. A higher level of perceived stigma among female participants is attributed to cultural norms and female roles within a family or broader social system. This study underlines that while India as a country in transition, societal and gender rules still impact perceived stigma and discrimination of people with mental illness.

Incorporating GIS and remote sensing for census population disaggregation

NASA Astrophysics Data System (ADS)

Wu, Shuo-Sheng'derek'

Census data are the primary source of demographic data for a variety of researches and applications. For confidentiality issues and administrative purposes, census data are usually released to the public by aggregated areal units. In the United States, the smallest census unit is census blocks. Due to data aggregation, users of census data may have problems in visualizing population distribution within census blocks and estimating population counts for areas not coinciding with census block boundaries. The main purpose of this study is to develop methodology for estimating sub-block areal populations and assessing the estimation errors. The City of Austin, Texas was used as a case study area. Based on tax parcel boundaries and parcel attributes derived from ancillary GIS and remote sensing data, detailed urban land use classes were first classified using a per-field approach. After that, statistical models by land use classes were built to infer population density from other predictor variables, including four census demographic statistics (the Hispanic percentage, the married percentage, the unemployment rate, and per capita income) and three physical variables derived from remote sensing images and building footprints vector data (a landscape heterogeneity statistics, a building pattern statistics, and a building volume statistics). In addition to statistical models, deterministic models were proposed to directly infer populations from building volumes and three housing statistics, including the average space per housing unit, the housing unit occupancy rate, and the average household size. After population models were derived or proposed, how well the models predict populations for another set of sample blocks was assessed. The results show that deterministic models were more accurate than statistical models. Further, by simulating the base unit for modeling from aggregating blocks, I assessed how well the deterministic models estimate sub-unit-level populations. I also assessed the aggregation effects and the resealing effects on sub-unit estimates. Lastly, from another set of mixed-land-use sample blocks, a mixed-land-use model was derived and compared with a residential-land-use model. The results of per-field land use classification are satisfactory with a Kappa accuracy statistics of 0.747. Model Assessments by land use show that population estimates for multi-family land use areas have higher errors than those for single-family land use areas, and population estimates for mixed land use areas have higher errors than those for residential land use areas. The assessments of sub-unit estimates using a simulation approach indicate that smaller areas show higher estimation errors, estimation errors do not relate to the base unit size, and resealing improves all levels of sub-unit estimates.

An integrated modeling approach to estimating Gunnison Sage-Grouse population dynamics: combining index and demographic data.

USGS Publications Warehouse

Davis, Amy J.; Hooten, Mevin B.; Phillips, Michael L.; Doherty, Paul F.

2014-01-01

Evaluation of population dynamics for rare and declining species is often limited to data that are sparse and/or of poor quality. Frequently, the best data available for rare bird species are based on large-scale, population count data. These data are commonly based on sampling methods that lack consistent sampling effort, do not account for detectability, and are complicated by observer bias. For some species, short-term studies of demographic rates have been conducted as well, but the data from such studies are typically analyzed separately. To utilize the strengths and minimize the weaknesses of these two data types, we developed a novel Bayesian integrated model that links population count data and population demographic data through population growth rate (λ) for Gunnison sage-grouse (Centrocercus minimus). The long-term population index data available for Gunnison sage-grouse are annual (years 1953–2012) male lek counts. An intensive demographic study was also conducted from years 2005 to 2010. We were able to reduce the variability in expected population growth rates across time, while correcting for potential small sample size bias in the demographic data. We found the population of Gunnison sage-grouse to be variable and slightly declining over the past 16 years.

Detection of Genital HPV Infection Using Urine Samples: a Population Based Study in India.

PubMed

Sabeena, Sasidharanpillai; Bhat, Parvati; Kamath, Veena; Mathew, Mary; Aswathyraj, Sushama; Devadiga, Santhosha; Prabhu, Suresha; Hindol, Maity; Chameetachal, Akhil; Krishnan, Anjana; Arunkumar, Govindakarnavar

2016-01-01

Cervical cancer is the second commonest cancer among Indian women and its association with human papilloma virus (HPV) is well established. This preventable cancer accounts for the maximum number of cancer related deaths among rural Indian women. Unlike in developed countries there are no organized cervical cancer screening programmes in India due to lack of resources and manpower. To detect genital HPV infection using urine samples among asymptomatic rural women in the age group of 18-65 years. The study area chosen was Perdoor village in Udupi Taluk, Karnataka State and all the women in the age group of 18-65 years formed the study cohort. A cross sectional study was conducted by house visits and 1,305 women were enrolled in the study. After taking written informed consent a data sheet was filled and early stream random urine samples were collected, transported to a laboratory at 4OC and aliquoted. Samples were tested using nested HPV PCR with PGMY09/11 and GP5+/6+ primers. Positive cases were genotyped by sequence analysis. Study participants included 1,134 sexually active and 171 unmarried women with a mean age at marriage of 22.1 (SD=3.9) years. Study area showed high female literacy rate of 86.6%. Five urine samples tested positive for HPV DNA (0.4%). We found very low genital HPV infection rate among women from monogamous community. This is the first major population based study carried out among asymptomatic rural women to detect genital HPV infectio from Karnataka using urine samples.

Association of sex hormones with physical, laboratory, and imaging markers of anthropometry in men and women from the general population.

PubMed

Seyfart, Tom; Friedrich, Nele; Kische, Hanna; Bülow, Robin; Wallaschofski, Henri; Völzke, Henry; Nauck, Matthias; Keevil, Brian G; Haring, Robin

2018-01-01

The aim of this study was to evaluate the association of sex hormones with anthropometry in a large population-based cohort, with liquid chromatography-mass spectrometry (LCMS)-based sex hormone measurements and imaging markers. Cross-sectional data from 957 men and women from the population-based Study of Health in Pomerania (SHIP) were used. Associations of a comprehensive panel of LCMS-measured sex hormones with anthropometric parameters, laboratory, and imaging markers were analyzed in multivariable regression models for the full sample and stratified by sex. Sex hormone measures included total testosterone (TT), free testosterone (fT), estrone and estradiol, androstenedione (ASD), dehydroepiandrosterone sulfate (DHEAS), and sex hormone-binding globulin (SHBG). Domains of anthropometry included physical measures (body-mass-index (BMI), waist circumference, waist-to-height-ratio, waist-to-hip-ratio, and hip circumference), laboratory measures of adipokines (leptin and vaspin), and magnet resonance imaging-based measures (visceral and subcutaneous adipose tissue). In men, inverse associations between all considered anthropometric parameters with TT were found: BMI (β-coefficient, standard error (SE): -0.159, 0.037), waist-circumference (β-coefficient, SE: -0.892, 0.292), subcutaneous adipose tissue (β-coefficient, SE: -0.156, 0.023), and leptin (β-coefficient, SE: -0.046, 0.009). In women TT (β-coefficient, SE: 1.356, 0.615) and estrone (β-coefficient, SE: 0.014, 0.005) were positively associated with BMI. In analyses of variance, BMI and leptin were inversely associated with TT, ASD, and DHEAS in men, but positively associated with estrone. In women, BMI and leptin were positively associated with all sex hormones. The present population-based study confirmed and extended previously reported sex-specific associations between sex hormones and various anthropometric markers of overweight and obesity.

Influence of CRTC1 polymorphisms on body mass index and fat mass in psychiatric patients and the general adult population.

PubMed

Choong, Eva; Quteineh, Lina; Cardinaux, Jean-René; Gholam-Rezaee, Mehdi; Vandenberghe, Frederik; Dobrinas, Maria; Bondolfi, Guido; Etter, Manuela; Holzer, Laurent; Magistretti, Pierre; von Gunten, Armin; Preisig, Martin; Vollenweider, Peter; Beckmann, Jacques S; Pralong, François P; Waeber, Gerard; Kutalik, Zoltan; Conus, Philippe; Bochud, Murielle; Eap, Chin B

2013-10-01

There is a high prevalence of obesity in psychiatric patients, possibly leading to metabolic complications and reducing life expectancy. The CREB-regulated transcription coactivator 1 (CRTC1) gene is involved in energy balance and obesity in animal models, but its role in human obesity is unknown. To determine whether polymorphisms within the CRTC1 gene are associated with adiposity markers in psychiatric patients and the general population. Retrospective and prospective data analysis and population-based samples at Lausanne and Geneva university hospitals in Switzerland and a private clinic in Lausanne, Switzerland. The effect of 3 CRTC1 polymorphisms on body mass index (BMI) and/or fat mass was investigated in a discovery cohort of psychiatric outpatients taking weight gain-inducing psychotropic drugs (sample 1, n = 152). The CRTC1 variant that was significantly associated with BMI and survived Bonferroni corrections for multiple comparison was then replicated in 2 independent psychiatric samples (sample 2, n = 174 and sample 3, n = 118) and 2 white population-based samples (sample 4, n = 5338 and sample 5, n = 123,865). Noninterventional studies. Difference in BMI and/or fat mass between CRTC1 genotype groups. Among the CRTC1 variants tested in the first psychiatric sample, only rs3746266A>G was associated with BMI (P(adjusted) = .003). In the 3 psychiatric samples, carriers of the rs3746266 G allele had a lower BMI than noncarriers (AA genotype) (sample 1, P = .001; sample 2, P = .05; and sample 3, P = .0003). In the combined analysis, excluding patients taking other weight gain-inducing drugs, G allele carriers (n = 98) had a 1.81-kg/m² lower BMI than noncarriers (n = 226; P < .0001). The strongest association was observed in women younger than 45 years, with a 3.87-kg/m² lower BMI in G allele carriers (n = 25) compared with noncarriers (n = 48; P < .0001), explaining 9% of BMI variance. In the population-based samples, the T allele of rs6510997C>T (a proxy of the rs3746266 G allele; r² = 0.7) was associated with lower BMI (sample 5, n = 123,865; P = .01) and fat mass (sample 4, n = 5338; P = .03). The strongest association with fat mass was observed in premenopausal women (n = 1192; P = .02). These findings suggest that CRTC1 contributes to the genetics of human obesity in psychiatric patients and the general population. Identification of high-risk subjects could contribute to a better individualization of the pharmacological treatment in psychiatry.

Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples.

PubMed

Marsh, Alan J; O'Sullivan, Orla; Hill, Colin; Ross, R Paul; Cotter, Paul D

2014-04-01

Kombucha is a sweetened tea beverage that, as a consequence of fermentation, contains ethanol, carbon dioxide, a high concentration of acid (gluconic, acetic and lactic) as well as a number of other metabolites and is thought to contain a number of health-promoting components. The sucrose-tea solution is fermented by a symbiosis of bacteria and yeast embedded within a cellulosic pellicle, which forms a floating mat in the tea, and generates a new layer with each successful fermentation. The specific identity of the microbial populations present has been the focus of attention but, to date, the majority of studies have relied on culture-based analyses. To gain a more comprehensive insight into the kombucha microbiota we have carried out the first culture-independent, high-throughput sequencing analysis of the bacterial and fungal populations of 5 distinct pellicles as well as the resultant fermented kombucha at two time points. Following the analysis it was established that the major bacterial genus present was Gluconacetobacter, present at >85% in most samples, with only trace populations of Acetobacter detected (<2%). A prominent Lactobacillus population was also identified (up to 30%), with a number of sub-dominant genera, not previously associated with kombucha, also being revealed. The yeast populations were found to be dominated by Zygosaccharomyces at >95% in the fermented beverage, with a greater fungal diversity present in the cellulosic pellicle, including numerous species not identified in kombucha previously. Ultimately, this study represents the most accurate description of the microbiology of kombucha to date. Copyright © 2013 Elsevier Ltd. All rights reserved.

A new urban landscape in East-Southeast Asia, 2000-2010

NASA Astrophysics Data System (ADS)

Schneider, A.; Mertes, C. M.; Tatem, A. J.; Tan, B.; Sulla-Menashe, D.; Graves, S. J.; Patel, N. N.; Horton, J. A.; Gaughan, A. E.; Rollo, J. T.; Schelly, I. H.; Stevens, F. R.; Dastur, A.

2015-03-01

East-Southeast Asia is currently one of the fastest urbanizing regions in the world, with countries such as China climbing from 20 to 50% urbanized in just a few decades. By 2050, these countries are projected to add 1 billion people, with 90% of that growth occurring in cities. This population shift parallels an equally astounding amount of built-up land expansion. However, spatially-and temporally-detailed information on regional-scale changes in urban land or population distribution do not exist; previous efforts have been either sample-based, focused on one country, or drawn conclusions from datasets with substantial temporal/spatial mismatch and variability in urban definitions. Using consistent methodology, satellite imagery and census data for >1000 agglomerations in the East-Southeast Asian region, we show that urban land increased >22% between 2000 and 2010 (from 155 000 to 189 000 km2), an amount equivalent to the area of Taiwan, while urban populations climbed >31% (from 738 to 969 million). Although urban land expanded at unprecedented rates, urban populations grew more rapidly, resulting in increasing densities for the majority of urban agglomerations, including those in both more developed (Japan, South Korea) and industrializing nations (China, Vietnam, Indonesia). This result contrasts previous sample-based studies, which conclude that cities are universally declining in density. The patterns and rates of change uncovered by these datasets provide a unique record of the massive urban transition currently underway in East-Southeast Asia that is impacting local-regional climate, pollution levels, water quality/availability, arable land, as well as the livelihoods and vulnerability of populations in the region.

The German Version of the Dutch Eating Behavior Questionnaire: Psychometric Properties, Measurement Invariance, and Population-Based Norms

PubMed Central

Hilbert, Anja; de Zwaan, Martina; Braehler, Elmar; Kersting, Anette

2016-01-01

The Dutch Eating Behavior Questionnaire is an internationally widely used instrument assessing different eating styles that may contribute to weight gain and overweight: emotional eating, external eating, and restraint. This study aimed to evaluate the psychometric properties of the 30-item German version of the DEBQ including its measurement invariance across gender, age, and BMI-status in a representative German population sample. Furthermore, we examined the distribution of eating styles in the general population and provide population-based norms for DEBQ scales. A representative sample of the German general population (N = 2513, age ≥ 14 years) was assessed with the German version of the DEBQ along with information on sociodemographic characteristics and body weight and height. The German version of the DEQB demonstrates good item characteristics and reliability (restraint: α = .92, emotional eating: α = .94, external eating: α = .89). The 3-factor structure of the DEBQ could be replicated in exploratory and confirmatory factor analyses and results of multi-group confirmatory factor analyses supported its metric and scalar measurement invariance across gender, age, and BMI-status. External eating was the most prevalent eating style in the German general population. Women scored higher on emotional and restrained eating scales than men, and overweight individuals scored higher in all three eating styles compared to normal weight individuals. Small differences across age were found for external eating. Norms were provided according to gender, age, and BMI-status. Our findings suggest that the German version of the DEBQ has good reliability and construct validity, and is suitable to reliably measure eating styles across age, gender, and BMI-status. Furthermore, the results demonstrate a considerable variation of eating styles across gender and BMI-status. PMID:27656879

The German Version of the Dutch Eating Behavior Questionnaire: Psychometric Properties, Measurement Invariance, and Population-Based Norms.

PubMed

Nagl, Michaela; Hilbert, Anja; de Zwaan, Martina; Braehler, Elmar; Kersting, Anette

The Dutch Eating Behavior Questionnaire is an internationally widely used instrument assessing different eating styles that may contribute to weight gain and overweight: emotional eating, external eating, and restraint. This study aimed to evaluate the psychometric properties of the 30-item German version of the DEBQ including its measurement invariance across gender, age, and BMI-status in a representative German population sample. Furthermore, we examined the distribution of eating styles in the general population and provide population-based norms for DEBQ scales. A representative sample of the German general population (N = 2513, age ≥ 14 years) was assessed with the German version of the DEBQ along with information on sociodemographic characteristics and body weight and height. The German version of the DEQB demonstrates good item characteristics and reliability (restraint: α = .92, emotional eating: α = .94, external eating: α = .89). The 3-factor structure of the DEBQ could be replicated in exploratory and confirmatory factor analyses and results of multi-group confirmatory factor analyses supported its metric and scalar measurement invariance across gender, age, and BMI-status. External eating was the most prevalent eating style in the German general population. Women scored higher on emotional and restrained eating scales than men, and overweight individuals scored higher in all three eating styles compared to normal weight individuals. Small differences across age were found for external eating. Norms were provided according to gender, age, and BMI-status. Our findings suggest that the German version of the DEBQ has good reliability and construct validity, and is suitable to reliably measure eating styles across age, gender, and BMI-status. Furthermore, the results demonstrate a considerable variation of eating styles across gender and BMI-status.

Within-Family Effects of Smoking during Pregnancy on ADHD: the Importance of Phenotype.

PubMed

Marceau, Kristine; Cinnamon Bidwell, L; Karoly, Hollis C; Evans, Allison Schettini; Todorov, Alexandre A; Palmer, Rohan H; Heath, Andrew C; Knopik, Valerie S

2018-05-01

We sought to test within- and between- family associations of smoking during pregnancy (SDP) and attention deficit-hyperactivity disorder (ADHD) symptoms using a structured interview based on the conventional Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) symptoms and the Strengths and Weaknesses of ADHD-Symptoms and Normal-Behavior (SWAN) scale, which is a population based measure that grew out of the notion that an ADHD diagnosis exists on the extreme end of a continuum of normative behaviors and includes both above- and below- average performance on attention and activity. We used a sibling-comparison approach in a sample of 173 families including siblings aged 7-16 years (52% male) drawn from the state of Missouri, USA, wherein mothers smoked during one pregnancy but not the other. There was a within-family effect of smoking during pregnancy on SWAN hyperactivity/impulsivity and SWAN total ADHD behaviors. The associations between SDP and DSM-IV-based ADHD symptom dimensions as well as SWAN inattention were explained by familial confounds. These findings suggest that SDP exerts a potentially causal effect on increased ADHD hyperactive/impulsive behaviors and that this SDP effect is best captured when hyperactivity/impulsivity is assessed more normatively across the population, rather than specifically assessing problematic behaviors via DSM symptoms. Thus, any potentially causal effect of SDP on ADHD symptom dimensions may be restricted to hyperactive/impulsive behaviors rather than inattention, and normative, non-DSM-IV based behavioral measures may provide a more sensitive test of mechanisms of SDP-ADHD symptom associations, particularly in non-clinical samples.

Perinatal factors and the risk of bipolar disorder in Finland.

PubMed

Chudal, Roshan; Sourander, Andre; Polo-Kantola, Päivi; Hinkka-Yli-Salomäki, Susanna; Lehti, Venla; Sucksdorff, Dan; Gissler, Mika; Brown, Alan S

2014-02-01

Complications during the perinatal period have been associated with neurodevelopmental disorders like schizophrenia and autism. However, similar studies on bipolar disorder (BPD) have been limited and the findings are inconsistent. The aim of this study was to examine the association between perinatal risk factors and BPD. This nested case-control study, based on the Finnish Prenatal Study of Bipolar Disorders (FIPS-B), identified 724 cases and 1419 matched controls from population based registers. Conditional logistic regression was used to examine the associations between perinatal factors and BPD adjusting for potential confounding due to maternal age, psychiatric history and educational level, place of birth, number of previous births and maternal smoking during pregnancy. Children delivered by planned cesarean section had a 2.5-fold increased risk of BPD (95% CI: 1.32-4.78, P<0.01). No association was seen between other examined perinatal risk factors and BPD. The limitations of this study include: the restriction in the sample to treated cases of BPD in the population, and usage of hospital based clinical diagnosis for case ascertainment. In addition, in spite of the large sample size, there was low power to detect associations for certain exposures including the lowest birth weight category and pre-term birth. Birth by planned cesarean section was associated with risk of BPD, but most other perinatal risk factors examined in this study were not associated with BPD. Larger studies with greater statistical power to detect less common exposures and studies utilizing prospective biomarker-based exposures are necessary in the future. © 2013 Published by Elsevier B.V.

Total and regional brain volumes in a population-based normative sample from 4 to 18 years: the NIH MRI Study of Normal Brain Development.

PubMed

2012-01-01

Using a population-based sampling strategy, the National Institutes of Health (NIH) Magnetic Resonance Imaging Study of Normal Brain Development compiled a longitudinal normative reference database of neuroimaging and correlated clinical/behavioral data from a demographically representative sample of healthy children and adolescents aged newborn through early adulthood. The present paper reports brain volume data for 325 children, ages 4.5-18 years, from the first cross-sectional time point. Measures included volumes of whole-brain gray matter (GM) and white matter (WM), left and right lateral ventricles, frontal, temporal, parietal and occipital lobe GM and WM, subcortical GM (thalamus, caudate, putamen, and globus pallidus), cerebellum, and brainstem. Associations with cross-sectional age, sex, family income, parental education, and body mass index (BMI) were evaluated. Key observations are: 1) age-related decreases in lobar GM most prominent in parietal and occipital cortex; 2) age-related increases in lobar WM, greatest in occipital, followed by the temporal lobe; 3) age-related trajectories predominantly curvilinear in females, but linear in males; and 4) small systematic associations of brain tissue volumes with BMI but not with IQ, family income, or parental education. These findings constitute a normative reference on regional brain volumes in children and adolescents.

Forensic efficiency parameters of the Investigator Argus X-12 kit in women from two Mestizo and seven Amerindian populations from Mexico.

PubMed

Cortés-Trujillo, I; Ramos-González, B; Salas-Salas, O; Zuñiga-Chiquette, F; Zetina Hernández, A; Martínez-Cortés, G; Ruiz-Hernández, M; González-Martín, A; Ferragut, J F; Rangel-Villalobos, H

2017-05-01

Allele frequency distribution and statistical parameters of forensic efficiency concerning the Investigator Argus X-12 kit (Qiagen, Hilden, Germany) were determined in a total sample of 641 unrelated Mexican females, including two Mestizo-admixed- populations (n=309) and seven Amerindian groups (n=332) from the main regions of the country. Most of the 12 X-STRs were in agreement with Hardy-Weinberg expectations in all nine Mexican populations. The power of discrimination in females (PD) and Median exclusion chance for trios (MEC T ) and duos (MEC D ) of this genetic system based on X-STRs were >99.99%. Although Mexican populations showed significant pairwise differentiation, a closer relationship was evident between Amerindian groups and nearby Mestizos, in agreement with historical records, previous genetic studies, and X-linked inheritance pattern expectations. Copyright © 2017 Elsevier B.V. All rights reserved.

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples..

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Estimation of pyrethroid pesticide intake using regression modeling of food groups based on composite dietary samples.

EPA Science Inventory

Population-based estimates of pesticide intake are needed to characterize exposure for particular demographic groups based on their dietary behaviors. Regression modeling performed on measurements of selected pesticides in composited duplicate diet samples allowed (1) estimation ...

Prevalence of modifiable cardiovascular risk factors among tea garden and general population in Dibrugarh, Assam, India.

PubMed

Mahanta, Tulika G; Joshi, Rajnish; Mahanta, Bhupendra N; Xavier, Denis

2013-09-01

Risk factors for cardiovascular disease (CVD) are multifactorial. Previous research has reported a high prevalence of CVD risk factors in tea-garden workers. This study was conducted to assess prevalence and level of modifiable cardiovascular risk factors among tea-garden and general population in Dibrugarh, Assam. A community-based cross-sectional study using the World Health Organization's (WHO) Stepwise methodology was conducted in Dibrugarh District of Assam. A multistep random sampling was done to include adults aged 35 years and above, with an intended equal sampling from tea-garden and general population. INTERHEART modifiable non-laboratory based risk score was estimated. Salt consumption was estimated using questionnaire-based methods in both subgroups. A total of 2826 individuals participated in the study (1231 [43.6%] tea-garden workers; 1595 [56.4%] general population). Tobacco consumption was higher in tea-garden workers as compared with general population (85.2% vs. 41.7% (p < 0.0001). Mean daily per-capita salt consumption was also significantly higher among tea-garden workers (29.60 vs. 22.89 g, p = 0.0001). Overall prevalence of hypertension was similar (44.4% vs. 45.2%), but among those who had hypertension, prevalence of undiagnosed hypertension was higher in tea-garden workers (82.8% vs. 74.4%, p < 0.0001). Tea-garden workers had lower BMI, were more physically active, and had a lower prevalence of diabetes mellitus and metabolic syndrome. Their INTERHEART modifiable risk score was also lower (1.44 [2.5] vs. 1.79 [2.8], p = 0.001). High prevalence of modifiable risk factors like tobacco consumption, high salt intake and high prevalence of hypertension indicates the need for early implementation of preventive actions in this population. Copyright © 2013 Ministry of Health, Saudi Arabia. Published by Elsevier Ltd. All rights reserved.

The prevalence of crash risk factors in a population-based study of motorcycle riders.

PubMed

de Rome, Liz; Fitzharris, Michael; Baldock, Matthew; Fernandes, Ralston; Ma, Alice; Brown, Julie

2016-09-01

Motorcyclists represent an increasing proportion of road traffic casualties but, while factors associated with crashes are readily identifiable, little is known about the prevalence of those risk factors in the motorcycling population. A stratified random-sampling frame was used to survey the population of registered motorcycles owners in New South Wales (NSW) when they attended motor registry offices. The postal codes in the State database of registered motorcycle were used to stratify the population into quartiles based on socioeconomic characteristics and to determine sample weights. Participants (n=506) represented 47% of eligible riders approached. On average participants were aged 43, rode 7h/week and had 17 years of riding experience. Estimates based on multiple ownership rates suggest motorcycle registration numbers exceed the active riding population by approximately 15%. Less than half rode under 101km/week, 25% rode over 300km/week and just 42% rode every day. More rode frequently for leisure (70%) than for commuting (53%) and over half rarely rode in dark (52%) or wet (67%) conditions. Most wore protective clothing - helmets (100%), jackets (82%), pants (56%), boots (57%) and gloves (73%). Those with traffic infringements (32%) were mostly for driving (25%), not riding (10%) offences. In the past year, 13% had one or more motorcycle crashes including minor spills and 76% one or more near-crash experiences. The youngest riders (15-19) reported the highest rates of exposure in kilometres, hours, frequency of riding and commuting. They also reported lower crash involvement (3%) but more near-crashes (80%). This study provides an account of the prevalence of key risk factors across age groups in a population of active motorcycle riders in NSW. Novice riders were represented in all age groups although most novices were under 40 years. These data can be used to guide the development of targeted countermeasures aimed at improving motorcycling safety for riders of different age groups. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Forensic genetic analyses in isolated populations with examples of central European Valachs and Roma.

PubMed

Ehler, Edvard; Vanek, Daniel

2017-05-01

Isolated populations present a constant threat to the correctness of forensic genetic casework. In this review article we present several examples of how analyzing samples from isolated populations can bias the results of the forensic statistics and analyses. We select our examples from isolated populations from central and southeastern Europe, namely the Valachs and the European Roma. We also provide the reader with general strategies and principles to improve the laboratory practice (best practice) and reporting of samples from supposedly isolated populations. These include reporting the precise population data used for computing the forensic statistics, using the appropriate θ correction factor for calculating allele frequencies, typing ancestry informative markers in samples of unknown or uncertain ethnicity and establishing ethnic-specific forensic databases. Copyright © 2017 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Sampling considerations for disease surveillance in wildlife populations

USGS Publications Warehouse

Nusser, S.M.; Clark, W.R.; Otis, D.L.; Huang, L.

2008-01-01

Disease surveillance in wildlife populations involves detecting the presence of a disease, characterizing its prevalence and spread, and subsequent monitoring. A probability sample of animals selected from the population and corresponding estimators of disease prevalence and detection provide estimates with quantifiable statistical properties, but this approach is rarely used. Although wildlife scientists often assume probability sampling and random disease distributions to calculate sample sizes, convenience samples (i.e., samples of readily available animals) are typically used, and disease distributions are rarely random. We demonstrate how landscape-based simulation can be used to explore properties of estimators from convenience samples in relation to probability samples. We used simulation methods to model what is known about the habitat preferences of the wildlife population, the disease distribution, and the potential biases of the convenience-sample approach. Using chronic wasting disease in free-ranging deer (Odocoileus virginianus) as a simple illustration, we show that using probability sample designs with appropriate estimators provides unbiased surveillance parameter estimates but that the selection bias and coverage errors associated with convenience samples can lead to biased and misleading results. We also suggest practical alternatives to convenience samples that mix probability and convenience sampling. For example, a sample of land areas can be selected using a probability design that oversamples areas with larger animal populations, followed by harvesting of individual animals within sampled areas using a convenience sampling method.

A school-based strategy to assess children's environmental exposures and related health effects in economically disadvantaged urban neighborhoods.

PubMed

Sexton, K; Greaves, I A; Church, T R; Adgate, J L; Ramachandran, G; Tweedie, R L; Fredrickson, A; Geisser, M; Sikorski, M; Fischer, G; Jones, D; Ellringer, P

2000-01-01

The School Health Initiative: Environment, Learning, Disease (SHIELD) study is a novel school-based investigation of children's environmental health in economically disadvantaged urban neighborhoods of Minneapolis. This article describes the study design and summarizes lessons learned about recruiting and monitoring this historically understudied population. The SHIELD study focused on measuring children's exposures to multiple environmental stressors [volatile organic chemicals (VOCs), environmental tobacco smoke, allergens, bioaerosols, metals, pesticides, polychlorinated biphenyls (PCB), phthalates] and exploring related effects on respiratory health (e.g., lung function) and learning outcomes (e.g., standardized test scores, academic achievement). It involved intensive exposure monitoring, including environmental measurements inside and outside the children's schools and inside their homes, personal measurements with passive dosimeters worn by the children, and biological marker measurements in blood and urine. The SHIELD participants comprised a stratified random sample of 153 "index" children and 51 of their siblings enrolled in grades 2-5 at two adjacent elementary schools. The Minneapolis Public Schools (MPS) assisted with identifying, contacting, recruiting, and monitoring this population, which traditionally is difficult to study because families/children are highly mobile, speak a diversity of languages, frequently do not have a telephone, endure economic hardships, often do not trust researchers, and have a spectrum of unconventional lifestyles and living arrangements. Using a school-based approach, the overall SHIELD enrollment (response) rate was 56.7%, with a wide disparity between English-speaking (41.7%) and non-English-speaking (71.0%) families/children. Most children remained involved in the study through both monitoring sessions and exhibited an acceptable degree of compliance with study protocols, including providing blood and urine samples. Results indicate that it is both practical and affordable to conduct probability-based exposure studies in this population, but that it is also important to improve our understanding of factors (e.g., cultural, economic, psychological, social) affecting the willingness of families/children to participate in such studies, with special emphasis on developing cost-effective recruitment methods.

(I Can’t Get No) Saturation: A simulation and guidelines for sample sizes in qualitative research

PubMed Central

2017-01-01

I explore the sample size in qualitative research that is required to reach theoretical saturation. I conceptualize a population as consisting of sub-populations that contain different types of information sources that hold a number of codes. Theoretical saturation is reached after all the codes in the population have been observed once in the sample. I delineate three different scenarios to sample information sources: “random chance,” which is based on probability sampling, “minimal information,” which yields at least one new code per sampling step, and “maximum information,” which yields the largest number of new codes per sampling step. Next, I use simulations to assess the minimum sample size for each scenario for systematically varying hypothetical populations. I show that theoretical saturation is more dependent on the mean probability of observing codes than on the number of codes in a population. Moreover, the minimal and maximal information scenarios are significantly more efficient than random chance, but yield fewer repetitions per code to validate the findings. I formulate guidelines for purposive sampling and recommend that researchers follow a minimum information scenario. PMID:28746358

A general unified framework to assess the sampling variance of heritability estimates using pedigree or marker-based relationships.

PubMed

Visscher, Peter M; Goddard, Michael E

2015-01-01

Heritability is a population parameter of importance in evolution, plant and animal breeding, and human medical genetics. It can be estimated using pedigree designs and, more recently, using relationships estimated from markers. We derive the sampling variance of the estimate of heritability for a wide range of experimental designs, assuming that estimation is by maximum likelihood and that the resemblance between relatives is solely due to additive genetic variation. We show that well-known results for balanced designs are special cases of a more general unified framework. For pedigree designs, the sampling variance is inversely proportional to the variance of relationship in the pedigree and it is proportional to 1/N, whereas for population samples it is approximately proportional to 1/N(2), where N is the sample size. Variation in relatedness is a key parameter in the quantification of the sampling variance of heritability. Consequently, the sampling variance is high for populations with large recent effective population size (e.g., humans) because this causes low variation in relationship. However, even using human population samples, low sampling variance is possible with high N. Copyright © 2015 by the Genetics Society of America.

Who gets how much: funding formulas in federal public health programs.

PubMed

Buehler, James W; Holtgrave, David R

2007-01-01

Federal public health programs use a mix of formula-based and competitive methods to allocate funds among states and other constituent jurisdictions. Characteristics of formula-based allocations used by a convenience sample of four programs, three from the Centers for Disease Control and Prevention and one from the Health Resources and Services Administration, are described to illustrate formula-based allocation methods in public health. Data sources in these public health formulas include population counts and funding proportions based on historical precedent. None include factors that adjust allocations based on variations in the availability of local resources or the cost of delivering services. Formula-funded activities are supplemented by programs that target specific prevention needs or encourage development of innovative methods to address emerging problems, using set-aside funds. A public health finance research agenda should address ways to improve the fit between funding allocation formulas and program objectives.

Difference in drug resistance patterns between minor HIV-1 populations in cerebrospinal fluid and plasma.

PubMed

Bergroth, T; Ekici, H; Gisslén, M; Hagberg, L; Sönnerborg, A

2009-02-01

The aim of the study was to determine to what extent unique drug resistance patterns appear in minor and major HIV-1 quasispecies in cerebrospinal fluid (CSF) as compared with blood. Forty-four plasma and CSF samples from 13 multi-treatment-experienced patients, seven of whom provided longitudinal samples, were included in the study. The subjects had failed antiretroviral therapy including lamivudine. The reverse transcriptase (RT) gene was examined by selective real-time polymerase chain reaction (SPCR), which can detect M184I/V mutants down to 0.2% of the viral population. SPCR revealed differences at amino acid position 184 in the plasma/CSF populations in 12 paired samples from eight patients. One plasma sample was positive by SPCR where direct sequencing showed wild-type M184. The other 11 paired samples showed quantitative differences in the mixed populations of the mutant or wild-type M184 quasispecies. Differences in other resistance-associated mutations between plasma and CSF viruses were also found by direct sequencing. In multi-treatment-experienced patients with therapy failure, differences in drug resistance patterns were found frequently between plasma and CSF in both minor and major viral populations. To what extent this was a true biological phenomenon remains to be established, and the clinical relevance of these findings is yet to be determined.

Prevalence of pfhrp2 and pfhrp3 gene deletions in Puerto Lempira, Honduras.

PubMed

Abdallah, Joseph F; Okoth, Sheila Akinyi; Fontecha, Gustavo A; Torres, Rosa Elena Mejia; Banegas, Engels I; Matute, María Luisa; Bucheli, Sandra Tamara Mancero; Goldman, Ira F; de Oliveira, Alexandre Macedo; Barnwell, John W; Udhayakumar, Venkatachalam

2015-01-21

Recent studies have demonstrated the deletion of the histidine-rich protein 2 (PfHRP2) gene (pfhrp2) in field isolates of Plasmodium falciparum, which could result in false negative test results when PfHRP2-based rapid diagnostic tests (RDTs) are used for malaria diagnosis. Although primary diagnosis of malaria in Honduras is determined based on microscopy, RDTs may be useful in remote areas. In this study, it was investigated whether there are deletions of the pfhrp2, pfhrp3 and their respective flanking genes in 68 P. falciparum parasite isolates collected from the city of Puerto Lempira, Honduras. In addition, further investigation considered the possible correlation between parasite population structure and the distribution of these gene deletions by genotyping seven neutral microsatellites. Sixty-eight samples used in this study, which were obtained from a previous chloroquine efficacy study, were utilized in the analysis. All samples were genotyped for pfhrp2, pfhrp3 and flanking genes by PCR. The samples were then genotyped for seven neutral microsatellites in order to determine the parasite population structure in Puerto Lempira at the time of sample collection. It was found that all samples were positive for pfhrp2 and its flanking genes on chromosome 8. However, only 50% of the samples were positive for pfhrp3 and its neighboring genes while the rest were either pfhrp3-negative only or had deleted a combination of pfhrp3 and its neighbouring genes on chromosome 13. Population structure analysis predicted that there are at least two distinct parasite population clusters in this sample population. It was also determined that a greater proportion of parasites with pfhrp3-(and flanking gene) deletions belonged to one cluster compared to the other. The findings indicate that the P. falciparum parasite population in the municipality of Puerto Lempira maintains the pfhrp2 gene and that PfHRP2-based RDTs could be considered for use in this region; however continued monitoring of parasite population will be useful to detect any parasites with deletions of pfhrp2.

New insights into the correlation structure of DSM-IV depression symptoms in the general population v. subsamples of depressed individuals.

PubMed

Foster, S; Mohler-Kuo, M

2018-06-01

Previous research failed to uncover a replicable dimensional structure underlying the symptoms of depression. We aimed to examine two neglected methodological issues in this research: (a) adjusting symptom correlations for overall depression severity; and (b) analysing general population samples v. subsamples of currently depressed individuals. Using population-based cross-sectional and longitudinal data from two nations (Switzerland, 5883 young men; USA, 2174 young men and 2244 young women) we assessed the dimensions of the nine DSM-IV depression symptoms in young adults. In each general-population sample and each subsample of currently depressed participants, we conducted a standardised process of three analytical steps, based on exploratory and confirmatory factor and bifactor analysis, to reveal any replicable dimensional structure underlying symptom correlations while controlling for overall depression severity. We found no evidence of a replicable dimensional structure across samples when adjusting symptom correlations for overall depression severity. In the general-population samples, symptoms correlated strongly and a single dimension of depression severity was revealed. Among depressed participants, symptom correlations were surprisingly weak and no replicable dimensions were identified, regardless of severity-adjustment. First, caution is warranted when considering studies assessing dimensions of depression because general population-based studies and studies of depressed individuals generate different data that can lead to different conclusions. This problem likely generalises to other models based on the symptoms' inter-relationships such as network models. Second, whereas the overall severity aligns individuals on a continuum of disorder intensity that allows non-affected individuals to be distinguished from affected individuals, the clinical evaluation and treatment of depressed individuals should focus directly on each individual's symptom profile.

Statistical sex determination from craniometrics: Comparison of linear discriminant analysis, logistic regression, and support vector machines.

PubMed

Santos, Frédéric; Guyomarc'h, Pierre; Bruzek, Jaroslav

2014-12-01

Accuracy of identification tools in forensic anthropology primarily rely upon the variations inherent in the data upon which they are built. Sex determination methods based on craniometrics are widely used and known to be specific to several factors (e.g. sample distribution, population, age, secular trends, measurement technique, etc.). The goal of this study is to discuss the potential variations linked to the statistical treatment of the data. Traditional craniometrics of four samples extracted from documented osteological collections (from Portugal, France, the U.S.A., and Thailand) were used to test three different classification methods: linear discriminant analysis (LDA), logistic regression (LR), and support vector machines (SVM). The Portuguese sample was set as a training model on which the other samples were applied in order to assess the validity and reliability of the different models. The tests were performed using different parameters: some included the selection of the best predictors; some included a strict decision threshold (sex assessed only if the related posterior probability was high, including the notion of indeterminate result); and some used an unbalanced sex-ratio. Results indicated that LR tends to perform slightly better than the other techniques and offers a better selection of predictors. Also, the use of a decision threshold (i.e. p>0.95) is essential to ensure an acceptable reliability of sex determination methods based on craniometrics. Although the Portuguese, French, and American samples share a similar sexual dimorphism, application of Western models on the Thai sample (that displayed a lower degree of dimorphism) was unsuccessful. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Optimal designs for population pharmacokinetic studies of the partner drugs co-administered with artemisinin derivatives in patients with uncomplicated falciparum malaria.

PubMed

Jamsen, Kris M; Duffull, Stephen B; Tarning, Joel; Lindegardh, Niklas; White, Nicholas J; Simpson, Julie A

2012-07-11

Artemisinin-based combination therapy (ACT) is currently recommended as first-line treatment for uncomplicated malaria, but of concern, it has been observed that the effectiveness of the main artemisinin derivative, artesunate, has been diminished due to parasite resistance. This reduction in effect highlights the importance of the partner drugs in ACT and provides motivation to gain more knowledge of their pharmacokinetic (PK) properties via population PK studies. Optimal design methodology has been developed for population PK studies, which analytically determines a sampling schedule that is clinically feasible and yields precise estimation of model parameters. In this work, optimal design methodology was used to determine sampling designs for typical future population PK studies of the partner drugs (mefloquine, lumefantrine, piperaquine and amodiaquine) co-administered with artemisinin derivatives. The optimal designs were determined using freely available software and were based on structural PK models from the literature and the key specifications of 100 patients with five samples per patient, with one sample taken on the seventh day of treatment. The derived optimal designs were then evaluated via a simulation-estimation procedure. For all partner drugs, designs consisting of two sampling schedules (50 patients per schedule) with five samples per patient resulted in acceptable precision of the model parameter estimates. The sampling schedules proposed in this paper should be considered in future population pharmacokinetic studies where intensive sampling over many days or weeks of follow-up is not possible due to either ethical, logistic or economical reasons.

Estimating the probability that the sample mean is within a desired fraction of the standard deviation of the true mean.

PubMed

Schillaci, Michael A; Schillaci, Mario E

2009-02-01

The use of small sample sizes in human and primate evolutionary research is commonplace. Estimating how well small samples represent the underlying population, however, is not commonplace. Because the accuracy of determinations of taxonomy, phylogeny, and evolutionary process are dependant upon how well the study sample represents the population of interest, characterizing the uncertainty, or potential error, associated with analyses of small sample sizes is essential. We present a method for estimating the probability that the sample mean is within a desired fraction of the standard deviation of the true mean using small (n<10) or very small (n < or = 5) sample sizes. This method can be used by researchers to determine post hoc the probability that their sample is a meaningful approximation of the population parameter. We tested the method using a large craniometric data set commonly used by researchers in the field. Given our results, we suggest that sample estimates of the population mean can be reasonable and meaningful even when based on small, and perhaps even very small, sample sizes.

Genome-wide analysis of signatures of selection in populations of African honey bees (Apis mellifera) using new web-based tools.

PubMed

Fuller, Zachary L; Niño, Elina L; Patch, Harland M; Bedoya-Reina, Oscar C; Baumgarten, Tracey; Muli, Elliud; Mumoki, Fiona; Ratan, Aakrosh; McGraw, John; Frazier, Maryann; Masiga, Daniel; Schuster, Stephen; Grozinger, Christina M; Miller, Webb

2015-07-10

With the development of inexpensive, high-throughput sequencing technologies, it has become feasible to examine questions related to population genetics and molecular evolution of non-model species in their ecological contexts on a genome-wide scale. Here, we employed a newly developed suite of integrated, web-based programs to examine population dynamics and signatures of selection across the genome using several well-established tests, including F ST, pN/pS, and McDonald-Kreitman. We applied these techniques to study populations of honey bees (Apis mellifera) in East Africa. In Kenya, there are several described A. mellifera subspecies, which are thought to be localized to distinct ecological regions. We performed whole genome sequencing of 11 worker honey bees from apiaries distributed throughout Kenya and identified 3.6 million putative single-nucleotide polymorphisms. The dense coverage allowed us to apply several computational procedures to study population structure and the evolutionary relationships among the populations, and to detect signs of adaptive evolution across the genome. While there is considerable gene flow among the sampled populations, there are clear distinctions between populations from the northern desert region and those from the temperate, savannah region. We identified several genes showing population genetic patterns consistent with positive selection within African bee populations, and between these populations and European A. mellifera or Asian Apis florea. These results lay the groundwork for future studies of adaptive ecological evolution in honey bees, and demonstrate the use of new, freely available web-based tools and workflows ( http://usegalaxy.org/r/kenyanbee ) that can be applied to any model system with genomic information.

The Value of a College Degree for Foster Care Alumni: Comparisons with General Population Samples

ERIC Educational Resources Information Center

Salazar, Amy M.

2013-01-01

Higher education is associated with substantial adult life benefits, including higher income and improved quality of life, among others. The current study compared adult outcomes of 250 foster care alumni college graduates with two samples of general population graduates to explore the role higher education plays in these young adults' lives.…

The efficacy of respondent-driven sampling for the health assessment of minority populations.

PubMed

Badowski, Grazyna; Somera, Lilnabeth P; Simsiman, Brayan; Lee, Hye-Ryeon; Cassel, Kevin; Yamanaka, Alisha; Ren, JunHao

2017-10-01

Respondent driven sampling (RDS) is a relatively new network sampling technique typically employed for hard-to-reach populations. Like snowball sampling, initial respondents or "seeds" recruit additional respondents from their network of friends. Under certain assumptions, the method promises to produce a sample independent from the biases that may have been introduced by the non-random choice of "seeds." We conducted a survey on health communication in Guam's general population using the RDS method, the first survey that has utilized this methodology in Guam. It was conducted in hopes of identifying a cost-efficient non-probability sampling strategy that could generate reasonable population estimates for both minority and general populations. RDS data was collected in Guam in 2013 (n=511) and population estimates were compared with 2012 BRFSS data (n=2031) and the 2010 census data. The estimates were calculated using the unweighted RDS sample and the weighted sample using RDS inference methods and compared with known population characteristics. The sample size was reached in 23days, providing evidence that the RDS method is a viable, cost-effective data collection method, which can provide reasonable population estimates. However, the results also suggest that the RDS inference methods used to reduce bias, based on self-reported estimates of network sizes, may not always work. Caution is needed when interpreting RDS study findings. For a more diverse sample, data collection should not be conducted in just one location. Fewer questions about network estimates should be asked, and more careful consideration should be given to the kind of incentives offered to participants. Copyright © 2017. Published by Elsevier Ltd.

Exploring cardiovascular health: the Healthy Life in Suriname (HELISUR) study. A protocol of a cross-sectional study

PubMed Central

Diemer, Frederieke S; Aartman, Jet Q; Karamat, Fares A; Baldew, Sergio M; Jarbandhan, Ameerani V; van Montfrans, Gert A; Oehlers, Glenn P; Brewster, Lizzy M

2014-01-01

Introduction Obesity, hypertension and diabetes are on a dramatic rise in low-income and middle-income countries, and this foretells an overwhelming increase in chronic disease burden from cardiovascular disease. Therefore, rapid action should be taken through preventive population-based programmes. However, in these regions, data on the population distribution of cardiovascular risk factors, and of intermediate and final end points for cardiovascular disease are scarce. The Healthy Life in Suriname (HELISUR) study is a cardiovascular population study in Suriname, which is part of the Caribbean Community. The HELISUR study is dedicated to provide data on risk factors and prevalent cardiovascular disease in the multiethnic population, which is mainly of African and Asian descent. Methods and analysis In a cross-sectional, observational population-based setting, a random representative sample of 1800 citizens aged between 18 and 70 years will be selected using a cluster household sampling method. Self-reported demographic, socioeconomic and (cardiovascular) health-related data will be collected. Physical examination will include the assessment of cardiovascular risk factors and prevalent cardiovascular disease. In addition, we will study cardiovascular haemodynamics non-invasively, as a novel intermediate outcome. Finally, fasting blood and overnight urine samples will be collected to monitor cardiometabolic risk factors. The main outcome will be descriptive in reporting the prevalence of risk factors and measures of (sub) clinical end organ damage, stratified for ethnicity and sex-age groups. Ethics and dissemination Ethical approval has been obtained from the State Secretary of Health. Data analysis and manuscript submission are scheduled for 2016. Findings will be disseminated in peer-reviewed journals, and at national, regional and international scientific meetings. Importantly, data will be presented to Surinamese policymakers and healthcare workers, to develop preventive strategies to combat the rapid rise of cardiovascular disease. PMID:25537786

Exploring cardiovascular health: the Healthy Life in Suriname (HELISUR) study. A protocol of a cross-sectional study.

PubMed

Diemer, Frederieke S; Aartman, Jet Q; Karamat, Fares A; Baldew, Sergio M; Jarbandhan, Ameerani V; van Montfrans, Gert A; Oehlers, Glenn P; Brewster, Lizzy M

2014-12-23

Obesity, hypertension and diabetes are on a dramatic rise in low-income and middle-income countries, and this foretells an overwhelming increase in chronic disease burden from cardiovascular disease. Therefore, rapid action should be taken through preventive population-based programmes. However, in these regions, data on the population distribution of cardiovascular risk factors, and of intermediate and final end points for cardiovascular disease are scarce. The Healthy Life in Suriname (HELISUR) study is a cardiovascular population study in Suriname, which is part of the Caribbean Community. The HELISUR study is dedicated to provide data on risk factors and prevalent cardiovascular disease in the multiethnic population, which is mainly of African and Asian descent. In a cross-sectional, observational population-based setting, a random representative sample of 1800 citizens aged between 18 and 70 years will be selected using a cluster household sampling method. Self-reported demographic, socioeconomic and (cardiovascular) health-related data will be collected. Physical examination will include the assessment of cardiovascular risk factors and prevalent cardiovascular disease. In addition, we will study cardiovascular haemodynamics non-invasively, as a novel intermediate outcome. Finally, fasting blood and overnight urine samples will be collected to monitor cardiometabolic risk factors. The main outcome will be descriptive in reporting the prevalence of risk factors and measures of (sub) clinical end organ damage, stratified for ethnicity and sex-age groups. Ethical approval has been obtained from the State Secretary of Health. Data analysis and manuscript submission are scheduled for 2016. Findings will be disseminated in peer-reviewed journals, and at national, regional and international scientific meetings. Importantly, data will be presented to Surinamese policymakers and healthcare workers, to develop preventive strategies to combat the rapid rise of cardiovascular disease. 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.

Population-wide weight loss and regain in relation to diabetes burden and cardiovascular mortality in Cuba 1980-2010: repeated cross sectional surveys and ecological comparison of secular trends.

PubMed

Franco, Manuel; Bilal, Usama; Orduñez, Pedro; Benet, Mikhail; Morejón, Alain; Caballero, Benjamín; Kennelly, Joan F; Cooper, Richard S

2013-04-09

To evaluate the associations between population-wide loss and gain in weight with diabetes prevalence, incidence, and mortality, as well as cardiovascular and cancer mortality trends, in Cuba over a 30 year interval. Repeated cross sectional surveys and ecological comparison of secular trends. Cuba and the province of Cienfuegos, from 1980 to 2010. Measurements in Cienfuegos included a representative sample of 1657, 1351, 1667, and 1492 adults in 1991, 1995, 2001, and 2010, respectively. National surveys included a representative sample of 14 304, 22 851, and 8031 participants in 1995, 2001, and 2010, respectively. Changes in smoking, daily energy intake, physical activity, and body weight were tracked from 1980 to 2010 using national and regional surveys. Data for diabetes prevalence and incidence were obtained from national population based registries. Mortality trends were modelled using national vital statistics. Rapid declines in diabetes and heart disease accompanied an average population-wide loss of 5.5 kg in weight, driven by an economic crisis in the mid-1990s. A rebound in population weight followed in 1995 (33.5% prevalence of overweight and obesity) and exceeded pre-crisis levels by 2010 (52.9% prevalence). The population-wide increase in weight was immediately followed by a 116% increase in diabetes prevalence and 140% increase in diabetes incidence. Six years into the weight rebound phase, diabetes mortality increased by 49% (from 9.3 deaths per 10 000 people in 2002 to 13.9 deaths per 10 000 people in 2010). A deceleration in the rate of decline in mortality from coronary heart disease was also observed. In relation to the Cuban experience in 1980-2010, there is an association at the population level between weight reduction and death from diabetes and cardiovascular disease; the opposite effect on the diabetes and cardiovascular burden was seen on population-wide weight gain.

[Genetic variability and differentiation of three Russian populations of yellow potato cyst nematode Globodera rostochiensis as revealed by nuclear markers].

PubMed

Khrisanfova, G G; Kharchevnikov, D A; Popov, I O; Zinov'eva, S V; Semenova, S K

2008-05-01

Genetic variability of yellow potato cyst nematode G. rostochiensis from three Russian populations (Karelia, Vladimir oblast, and Moscow oblast) was investigated using two types of nuclear markers. Using RAPD markers identified with the help of six random primers (P-29, OPA-10, OPT-14, OPA-11, OPB-11, and OPH-20), it was possible to distinguish Karelian population from the group consisting of the populations from two adjacent regions (Moscow oblast and Vladimir oblast). Based on the combined matrix, containing 294 RAPD fragments, dendrogram of genetic differences was constructed, and the indices of genetic divergence and partition (P, H, and G(st)), as well as the gene flow indices N(m) between the nematode samples examined, were calculated. The dendrogram structure, genetic diversity indices, and variations of genetic distances between single individuals in each population from Karelia and Central Russia pointed to genetic isolation and higher genetic diversity of the nematodes from Karelia. Based on polymorphism of rDNA first intergenic spacer ITS1, attribution of all populations examined to the species G. rostochiensis was proved. Small variations of the ITS1 sequence in different geographic populations of nematodes from different regions of the species world range did not allow isolation of separate groups within the species. Possible factors (including interregional transportations of seed potato) affecting nematode population structure in Russia are discussed.

Estimating numbers of females with cubs-of-the-year in the Yellowstone grizzly bear population

USGS Publications Warehouse

Keating, K.A.; Schwartz, C.C.; Haroldson, M.A.; Moody, D.

2001-01-01

For grizzly bears (Ursus arctos horribilis) in the Greater Yellowstone Ecosystem (GYE), minimum population size and allowable numbers of human-caused mortalities have been calculated as a function of the number of unique females with cubs-of-the-year (FCUB) seen during a 3- year period. This approach underestimates the total number of FCUB, thereby biasing estimates of population size and sustainable mortality. Also, it does not permit calculation of valid confidence bounds. Many statistical methods can resolve or mitigate these problems, but there is no universal best method. Instead, relative performances of different methods can vary with population size, sample size, and degree of heterogeneity among sighting probabilities for individual animals. We compared 7 nonparametric estimators, using Monte Carlo techniques to assess performances over the range of sampling conditions deemed plausible for the Yellowstone population. Our goal was to estimate the number of FCUB present in the population each year. Our evaluation differed from previous comparisons of such estimators by including sample coverage methods and by treating individual sightings, rather than sample periods, as the sample unit. Consequently, our conclusions also differ from earlier studies. Recommendations regarding estimators and necessary sample sizes are presented, together with estimates of annual numbers of FCUB in the Yellowstone population with bootstrap confidence bounds.

Gene flow and genetic structure of Bactrocera carambolae (Diptera, Tephritidae) among geographical differences and sister species, B. dorsalis, inferred from microsatellite DNA data.

PubMed

Aketarawong, Nidchaya; Isasawin, Siriwan; Sojikul, Punchapat; Thanaphum, Sujinda

2015-01-01

The Carambola fruit fly, Bactrocera carambolae, is an invasive pest in Southeast Asia. It has been introduced into areas in South America such as Suriname and Brazil. Bactrocera carambolae belongs to the Bactrocera dorsalis species complex, and seems to be separated from Bactrocera dorsalis based on morphological and multilocus phylogenetic studies. Even though the Carambola fruit fly is an important quarantine species and has an impact on international trade, knowledge of the molecular ecology of Bactrocera carambolae, concerning species status and pest management aspects, is lacking. Seven populations sampled from the known geographical areas of Bactrocera carambolae including Southeast Asia (i.e., Indonesia, Malaysia, Thailand) and South America (i.e., Suriname), were genotyped using eight microsatellite DNA markers. Genetic variation, genetic structure, and genetic network among populations illustrated that the Suriname samples were genetically differentiated from Southeast Asian populations. The genetic network revealed that samples from West Sumatra (Pekanbaru, PK) and Java (Jakarta, JK) were presumably the source populations of Bactrocera carambolae in Suriname, which was congruent with human migration records between the two continents. Additionally, three populations of Bactrocera dorsalis were included to better understand the species boundary. The genetic structure between the two species was significantly separated and approximately 11% of total individuals were detected as admixed (0.100 ≤ Q ≤ 0.900). The genetic network showed connections between Bactrocera carambolae and Bactrocera dorsalis groups throughout Depok (DP), JK, and Nakhon Sri Thammarat (NT) populations. These data supported the hypothesis that the reproductive isolation between the two species may be leaky. Although the morphology and monophyly of nuclear and mitochondrial DNA sequences in previous studies showed discrete entities, the hypothesis of semipermeable boundaries may not be rejected. Alleles at microsatellite loci could be introgressed rather than other nuclear and mitochondrial DNA. Bactrocera carambolae may be an incipient rather than a distinct species of Bactrocera dorsalis. Regarding the pest management aspect, the genetic sexing Salaya5 strain (SY5) was included for comparison with wild populations. The SY5 strain was genetically assigned to the Bactrocera carambolae cluster. Likewise, the genetic network showed that the strain shared greatest genetic similarity to JK, suggesting that SY5 did not divert away from its original genetic makeup. Under laboratory conditions, at least 12 generations apart, selection did not strongly affect genetic compatibility between the strain and wild populations. This knowledge further confirms the potential utilization of the Salaya5 strain in regional programs of area-wide integrated pest management using SIT.

Gene flow and genetic structure of Bactrocera carambolae (Diptera, Tephritidae) among geographical differences and sister species, B. dorsalis, inferred from microsatellite DNA data

PubMed Central

Aketarawong, Nidchaya; Isasawin, Siriwan; Sojikul, Punchapat; Thanaphum, Sujinda

2015-01-01

Abstract The Carambola fruit fly, Bactrocera carambolae, is an invasive pest in Southeast Asia. It has been introduced into areas in South America such as Suriname and Brazil. Bactrocera carambolae belongs to the Bactrocera dorsalis species complex, and seems to be separated from Bactrocera dorsalis based on morphological and multilocus phylogenetic studies. Even though the Carambola fruit fly is an important quarantine species and has an impact on international trade, knowledge of the molecular ecology of Bactrocera carambolae, concerning species status and pest management aspects, is lacking. Seven populations sampled from the known geographical areas of Bactrocera carambolae including Southeast Asia (i.e., Indonesia, Malaysia, Thailand) and South America (i.e., Suriname), were genotyped using eight microsatellite DNA markers. Genetic variation, genetic structure, and genetic network among populations illustrated that the Suriname samples were genetically differentiated from Southeast Asian populations. The genetic network revealed that samples from West Sumatra (Pekanbaru, PK) and Java (Jakarta, JK) were presumably the source populations of Bactrocera carambolae in Suriname, which was congruent with human migration records between the two continents. Additionally, three populations of Bactrocera dorsalis were included to better understand the species boundary. The genetic structure between the two species was significantly separated and approximately 11% of total individuals were detected as admixed (0.100 ≤ Q ≤ 0.900). The genetic network showed connections between Bactrocera carambolae and Bactrocera dorsalis groups throughout Depok (DP), JK, and Nakhon Sri Thammarat (NT) populations. These data supported the hypothesis that the reproductive isolation between the two species may be leaky. Although the morphology and monophyly of nuclear and mitochondrial DNA sequences in previous studies showed discrete entities, the hypothesis of semipermeable boundaries may not be rejected. Alleles at microsatellite loci could be introgressed rather than other nuclear and mitochondrial DNA. Bactrocera carambolae may be an incipient rather than a distinct species of Bactrocera dorsalis. Regarding the pest management aspect, the genetic sexing Salaya5 strain (SY5) was included for comparison with wild populations. The SY5 strain was genetically assigned to the Bactrocera carambolae cluster. Likewise, the genetic network showed that the strain shared greatest genetic similarity to JK, suggesting that SY5 did not divert away from its original genetic makeup. Under laboratory conditions, at least 12 generations apart, selection did not strongly affect genetic compatibility between the strain and wild populations. This knowledge further confirms the potential utilization of the Salaya5 strain in regional programs of area-wide integrated pest management using SIT. PMID:26798262

Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards.

PubMed

Bornstein, Marc H; Jager, Justin; Putnick, Diane L

2013-12-01

Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study's target population, whether they yield representative and generalizable estimates of subsamples within a study's target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce "noise" related to variation in subsamples and whether that "noise" can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting.

Sampling in Developmental Science: Situations, Shortcomings, Solutions, and Standards

PubMed Central

Bornstein, Marc H.; Jager, Justin; Putnick, Diane L.

2014-01-01

Sampling is a key feature of every study in developmental science. Although sampling has far-reaching implications, too little attention is paid to sampling. Here, we describe, discuss, and evaluate four prominent sampling strategies in developmental science: population-based probability sampling, convenience sampling, quota sampling, and homogeneous sampling. We then judge these sampling strategies by five criteria: whether they yield representative and generalizable estimates of a study’s target population, whether they yield representative and generalizable estimates of subsamples within a study’s target population, the recruitment efforts and costs they entail, whether they yield sufficient power to detect subsample differences, and whether they introduce “noise” related to variation in subsamples and whether that “noise” can be accounted for statistically. We use sample composition of gender, ethnicity, and socioeconomic status to illustrate and assess the four sampling strategies. Finally, we tally the use of the four sampling strategies in five prominent developmental science journals and make recommendations about best practices for sample selection and reporting. PMID:25580049

A comparison of the views of extension agents and farmers regarding extension education courses in Dezful, Iran

NASA Astrophysics Data System (ADS)

Nazarzadeh Zare, Mohsen; Dorrani, Kamal; Gholamali Lavasani, Masoud

2012-11-01

Background and purpose : This study examines the views of farmers and extension agents participating in extension education courses in Dezful, Iran, with regard to problems with these courses. It relies upon a descriptive methodology, using a survey as its instrument. Sample : The statistical population consisted of 5060 farmers and 50 extension agents; all extension agents were studied owing to their small population and a sample of 466 farmers was selected based on the stratified ratio sampling method. For the data analysis, statistical procedures including the t-test and factor analysis were used. Results : The results of factor analysis on the views of farmers indicated that these courses have problems such as inadequate use of instructional materials by extension agents, insufficient employment of knowledgeable and experienced extension agents, bad and inconvenient timing of courses for farmers, lack of logical connection between one curriculum and prior ones, negligence in considering the opinions of farmers in arranging the courses, and lack of information about the time of courses. The findings of factor analysis on the views of extension agents indicated that these courses suffer from problems such as use of consistent methods of instruction for teaching curricula, and lack of continuity between courses and their levels and content. Conclusions : Recommendations include: listening to the views of farmers when planning extension courses; providing audiovisual aids, pamphlets and CDs; arranging courses based on convenient timing for farmers; using incentives to encourage participation; and employing extension agents with knowledge of the latest agricultural issues.

Sequential sampling of ribes populations in the control of white pine blister rust (Cronartium ribicola Fischer) in California

Treesearch

Harold R. Offord

1966-01-01

Sequential sampling based on a negative binomial distribution of ribes populations required less than half the time taken by regular systematic line transect sampling in a comparison test. It gave the same control decision as the regular method in 9 of 13 field trials. A computer program that permits sequential plans to be built readily for other white pine regions is...

Microsatellite genetic distances between oceanic populations of the humpback whale (Megaptera novaeangliae).

PubMed

Valsecchi, E; Palsbøll, P; Hale, P; Glockner-Ferrari, D; Ferrari, M; Clapham, P; Larsen, F; Mattila, D; Sears, R; Sigurjonsson, J; Brown, M; Corkeron, P; Amos, B

1997-04-01

Mitochondrial DNA haplotypes of humpback whales show strong segregation between oceanic populations and between feeding grounds within oceans, but this highly structured pattern does not exclude the possibility of extensive nuclear gene flow. Here we present allele frequency data for four microsatellite loci typed across samples from four major oceanic regions: the North Atlantic (two mitochondrially distinct populations), the North Pacific, and two widely separated Antarctic regions, East Australia and the Antarctic Peninsula. Allelic diversity is a little greater in the two Antarctic samples, probably indicating historically greater population sizes. Population subdivision was examined using a wide range of measures, including Fst, various alternative forms of Slatkin's Rst, Goldstein and colleagues' delta mu, and a Monte Carlo approximation to Fisher's exact test. The exact test revealed significant heterogeneity in all but one of the pairwise comparisons between geographically adjacent populations, including the comparison between the two North Atlantic populations, suggesting that gene flow between oceans is minimal and that dispersal patterns may sometimes be restricted even in the absence of obvious barriers, such as land masses, warm water belts, and antitropical migration behavior. The only comparison where heterogeneity was not detected was the one between the two Antarctic population samples. It is unclear whether failure to find a difference here reflects gene flow between the regions or merely lack of statistical power arising from the small size of the Antarctic Peninsula sample. Our comparison between measures of population subdivision revealed major discrepancies between methods, with little agreement about which populations were most and least separated. We suggest that unbiased Rst (URst, see Goodman 1995) is currently the most reliable statistic, probably because, unlike the other methods, it allows for unequal sample sizes. However, in view of the fact that these alternative measures often contradict one another, we urge caution in the use of microsatellite data to quantify genetic distance.